Looking for a little information about Exposure to the Right, here are some articles that will help to explain the benefits of this exposure technique.
http://www.luminous-landscape.com/tutorials/expose-right.shtml
http://www.luminous-landscape.com/tutorials/optimizing_exposure.shtml
The luminous-landscape information was provided thanks to Michael Reichmann.
Loading the moduleTo use this feature, you must first load the module in the module tab:
(https://s22.postimg.cc/rzw8srhb3/Load.png?dl=1)
After restarting the camera, you will now find the module located in the Expo tab:
(https://s22.postimg.cc/xo2jjntdb/Expo.jpg?dl=1)
Using the moduleFirst, lets take a look at the default options:
(https://s22.postimg.cc/5b71t6s7j/ETTR.png?dl=1)
Trigger Mode:
- Always On: AETTR is always active. In photo mode through the viewfinder, this means that AETTR is always inspecting the exposure in the image review, and setting the exposure settings for the next shot. In Live View, this means that AETTR is always looking at the image in the live view, and adjusting the exposure settings as necessary.
- Auto Snap: After taking a shot, AETTR will take another shot if necessary.
- Press Set: AETTR activates by pressing the SET button. In photo mode through the viewfinder, AETTR will turn on live view, determine the correct exposure settings, and return to photo mode. In live view modes, AETTR will determine the correct exposure settings.
- HalfS DblClick: This functionality is exactly like Press Set above, except the trigger button is half pressing the shutter button twice.
Slowest shutter:
- Set the slowest shutter speed that AETTR is allowed to use.
Highlight ignore:
- Set the amount of pixels in the image, that are allowed to be overexposed.
- This works like an specular highlight control.
Midtone SNR limit:
- Set the minimum Signal to Noise Ratio of the median brightness level.
- "The median "brightness" gives you the signal level, so we can use the SNR. So, when I say the midtone SNR is 5 EV, this means half of the image has a SNR less than 5 EV, and the other half has a SNR higher than 5 EV. Pretty easy and statistically robust".
- http://www.magiclantern.fm/forum/index.php?topic=5200.msg70012#msg70012
- Note: This setting by itself, overrides the overexposure control of AETTR. This means, that AETTR will overexpose the image as needed, to hit the SNR limit set here.
Shadow SNR limit:
- Set the minimum Signal to Noise Ratio of the shadows.
- "For shadows, I've chosen the 5% percentile. So, in this context, the shadows having a SNR of 3 EV means 5% of the image pixels have a SNR lower than 3 EV, and the other pixels will be brighter than that".
- http://www.magiclantern.fm/forum/index.php?topic=5200.msg70012#msg70012
- Note: This setting by itself, overrides the overexposure control of AETTR. This means, that AETTR will overexpose the image as needed, to hit the SNR limit set here.
Link to Dual ISO
- Let ETTR change Dual ISO settings so you get the SNR values in mids & shadows. It will disable dual ISO if not needed.
- With the SNR limits above, instead of simply allowing overexposure to reach the set SNR limits, this will enable dual ISO instead, allowing you to retain full highlight detail (minus dual ISO deficiencies), while still capturing the required SNR in the midtones and/or shadows.
Advanced settings(https://s22.postimg.cc/fl9gsf2nj/Advanced.png?dl=1)
Exposure target:
- Where to place the highlights with respect to overexposure.
Allow Clipping:
- Off: Only allow overexposure as per the highlight ignore setting.
- Green Channel: Ignore the green channel, and calculate exposure settings from the other channels.
- Any Channel: Allow some overexposure, over and above the highlight ignore setting, in any channel.
Link to Canon shutter
- Set the slowest shutter speed AETTR is allowed to use, via Canon exposure settings.
- This allows you to set the slowest shutter speed with the scroll wheel/main dial.
Show metered areas
- Show where the white point and SNR levels are metered (what exactly is considered highlight, midtone and shadow).
- Colored zebras represent those areas.
Show debug info
Hey mate, good job. I was going to have a go at this, but you did a much better job. I'll add some more information as time permits.
A couple of things to note.
Quote from: RenatoPhoto on May 25, 2013, 07:24:06 PM
ETTR BENEFITS SUMMARY: The great advantages of ETTR, in case that all of this reading was way above your head here are the potential benefits:
1. Reduce the noise in the underexposed areas.
2. Capture more detail and less noise. i.e. The amount of usable information (signal) is higher than the noise, improving the Signal-to-Noise Ratio.
3. In most cases ETTR allows to use lower ISOs since more light is reaching the sensor for example by lowering the shutter speed.
4. ETTR in RAW mode is more accurate and the implementation of histograms in jpeg.
5. Also posted by one of our colleagues, there should more color accuracy as noted here:
http://www.magiclantern.fm/forum/index.php?topic=5149.msg31285#msg31285
ETTR does not capture less noise. The logarithmic curve of SNR remains the same for all ISO's. We are merely pushing the signal to the right of the curve where the SNR ratio is greater. The noise however, has remained the same.
In most cases, ETTR requires a higher ISO. ETTR requires a longer exposure time, if you are already at the minimum shutter and aperture that the shot requires, a higher ISO is needed.
At POTN, they call it HAMSTTR (http://"http://photography-on-the.net/forum/showthread.php?p=8534003#post8534003") to take into account the ISO changes.
Great post man!
@ Audionut
I followed the epic HAMSTTR thread and wanted to proof to myself that lower ISO is better for ETTR so I setup a test where the camera calculated the ETTR amount using the ETTR hint provided in the histogram. According to the algorithms programmed by A1lex the ETTR hint tells you how many EV you need to change the exposure to reach optimum ETTR.
So first I setup the ETTR at the following values i.e.
ETTR percentile 98%
ETTR target level -05. EV
Clipping mode No clipping
Camera 5D3 with 180mm f/3.5
First image (top right) is in AV mode to hold the aperture at 6,3 and ISO in AUTO MODE. The camera chose 1/200 with ISO 1250. At this settings the ETTR hint from ML calculated that I could have overexposed by +1.9 EV
In the next images I set the camera in manual mode and found some settings at different ISO where the ETTR hint was close to zero. This would mean that for those settings the image was correctly exposed based on ETTR theory. I went from ISO 4000 all the way to ISO 100.
The images were processed with Photoshop and all were set to Auto exposure so tha ACR would find its optimal level of correction and have all images looking the same. Then I cropped at 400% to show the noise and small details.
(http://s20.postimg.org/v0xpyay0d/Comparison_ettr.jpg)
It is quite clear that lowering the ISO also greatly lowers the noise. It is also quite amazing how much noise can be removed by the ETTR technique by comparing the first image with the one below at ISO 1600.
Next I enabled the ETTR feature and set my Slowest shutter at 1/2. Took some shots an noticed that ETTR ON it did not immediately drive the settings towards ISO 100. With the current algorithms the ETTR system will change the exposure to obtain E=0 but it will not change ISO set manually in the camera unless the required EV change should be more that +- 3 EV.
For example if I manually changed the ISO to 4000 and the shutter to 250, which the camera interpreted a properly exposed by looking at the Exposure Level indicator = 0. The ETTR system would only change the shutter speed to 160 and leave the ISO at 4000. Now if I set the speed so that my Exposure Level indicator >= 3, the the ISO would change. For example set the speed to 1/40 (EL=3) and the I
set the ISO=4000, the camera would automatically lower the ISO to 1000 and leave the speed to 1/40 which showed E=0.
Conclusion 1 = Lower ISO produce better ETTR images that higher ISOs.
Conclusion 2: The ETTR system is doing a great job but it is not exploring the possibility of lowering the speed all the way down to my setting of 1/2 sec. Some people, such as those found in the HAMSTTR thread do believe that higher ISO is better, but IMHO they are partially wrong. If you cannot lower the shutter speed then you must raise the ISO to obtain proper ETTR, and in this case a higher ISO is better. But if you can lower the shutter speed and reach a lower ISO, and do the same proper ETTR at that lower ISO, the image will be much better.
Quote from: RenatoPhoto on May 26, 2013, 09:48:08 PM
Conclusion 2: If you cannot lower the shutter speed then you must raise the ISO to obtain proper ETTR, and in this case a higher ISO is better. But if you can lower the shutter speed and reach a lower ISO, and do the same proper ETTR at that lower ISO, the image will be much better.
This is correct, but I think your understanding of what I was explaining is flawed :)
When ascertaining the results of shutter/aperture/ISO (exposure triangle), only 1 option can be examined at a time, the other 2 must remain the same.
ETTR works by increasing exposure to the sensor saturation point.
So by saying the lower ISO is better, and showing the results of this with a slower shutter speed also, the result is flawed, as the lower ISO also has the advantage of a longer exposure from a slower shutter speed.
A true test of ISO (in ETTR) is to have a set shutter and aperture that doesn't change.
Below is a quick test showing my dirty table.
All shots were with a shutter of 1/15 and an aperture of f/4.0. Note: A minimum shutter and aperture must be taken into account. In the field, we cannot just set whatever shutter/aperture we want, as we are limited by our DOF requirements and minimum shutter if handheld etc.
note: The post exposure results are direct from ML and performed in post, and the image sizes are the crops.
ISO 100 - post exposure +2.25EV - 211.05KB(https://s15.postimg.cc/5e3fac7ln/100.jpg)
ISO 200 - post exposure +1.26EV - 174.39KB(https://s15.postimg.cc/4okmxzmhn/200.jpg)
ISO 400 - post exposure +0.22EV - 154.07KB(https://s15.postimg.cc/thu6yq5iz/400.jpg)
ISO 800 - post exposure -0.77EV - 146.94KB(https://s15.postimg.cc/iv0dt8ki3/800.jpg)
ISO 1600 - post exposure -1.79EV - 143.27KB(https://s15.postimg.cc/rd9txkjaz/1600.jpg)
ISO 3200 - post exposure - -2.79EV - 142.42KB(https://s15.postimg.cc/y3qb723wr/3200.jpg)
And some examples from a copped area that was further in the shadows.
Exposure results are the same.
ISO 100 - 212.03KB(https://s15.postimg.cc/v9n5tmwln/100-1.jpg)
ISO 200 - 171.75KB(https://s15.postimg.cc/uk4dh6w17/200-1.jpg)
ISO 400 - 148.30KB(https://s15.postimg.cc/uwvrnfywb/400-1.jpg)
ISO 800 - 143.48KB(https://s15.postimg.cc/eyn1x84nf/800-1.jpg)
ISO 1600 - 135.01KB(https://s15.postimg.cc/6t4zz3qp7/1600-1.jpg)
ISO 3200 - 134.02KB(https://s15.postimg.cc/3z1ulqgu3/3200-1.jpg)
Some more points to note.
Some ISO's are underexposed in camera and increased in post as I wanted a minimum shutter of 1/15. 1/15 is below the handhold capability of most body/lens/user combos, but felt is was a good speed (with the available light I had for the test) to highlight my point.
Of course a slower shutter would have been better, but it highlights that sometimes you must use a higher ISO for correct exposure, you can't just keep slowing the shutter.
Conclusion.The shadows are where all the action is! The highlights have enough Signal To Noise ratio at almost all ISO's.
It gets hard to see the differences in noise in some of the test results. Hint: Look at the file sizes. They keep reducing the higher the ISO (less noise).
Note, the results below reference a Canon 5D3. The results hold true for all cameras, it's just that other bodies will have different SNR results for different light levels.
The SNR of an ISO bump reduces by 3dB for almost all ISO's. Reference this DXO chart.
(https://s15.postimg.cc/xe7iuog7v/SNR18.png)
In other words, the noise doubles for every doubling of ISO.
Now reference the SNR of all ISO's at all light levels.
(https://s15.postimg.cc/5e3faga7f/SNR.png)
Here we can see again, that in the highlights, even ISO 6400 still has a SNR of 30dB, which is greater (by 6dB) then the SNR of ISO 100 @ 1% light level.
And here is where it gets interesting. If we have an exposure @ ISO 100 that results in our shadows being around the 0.1% light level, we can see that we only have 6dB of SNR (ouch).
Now if we take the same scene and increase ISO to 200, we double the exposure, so that 0.1% light level now lies at 0.2% exposure on the Full SNR scale.
ISO 400 0.4%
ISO 800 0.8%
ISO 1600 1.6%
ISO 3200 3.2%
ISO 6400 6.4%
And at 6.4% light level, ISO 6400 has a SNR of around 18dB vs the 6dB of the same shot at ISO 100. Yes, the highlights and midtones will have a higher noise level (lower SNR), but our shadows (where lets face it, all the noise actually is, or more correctly, where the noise is noticeable due to low SNR) OMG. We gained 12dB of SNR just from using a higher ISO. And these results are reflected in the sample images above.
Yes we can lower shutter speed and/or reduce the aperture to achieve the same results, and if the situation allows you to do so, this is the best way to ETTR, but when you can no longer reduce shutter and/or aperture, hopefully I've shown that increasing the ISO can actually be beneficial. It's not simply a case of higher ISO = more noise.
It's better to increase ISO to gain the best exposure, then to increase exposure in post.
And herein lies the advantage of ETTR. Bring those shadows out of the noise (higher SNR) and then as an added benefit, reduce the entire exposure (and the noise ;)) in post. Win all the way.
There is a lot of physics going on here. I commend these two articles to those who wish to have a greater understanding of their sensors:
http://www.clarkvision.com/articles/iso/
And for the 5DIII owners
http://www.clarkvision.com/articles/evaluation-canon-5diii/
Cheers
Very good thread.
I have been a huge supporter of ETTR during the years as it's another way of making the most out of our cameras.
@audionut: sorry for breaking the thread flow but apparently (from the cigarette package i see) you are from Australia.
What area?
Quote from: garry23 on May 27, 2013, 06:41:45 AM
I commend these two articles to those who wish to have a greater understanding of their sensors:
Excellent read. Thanks.
Quote from: ilguercio on May 27, 2013, 07:02:46 AM
What area?
SEQ. Not Brisbane :)
I'm sorry but after reading this thread and all the linked articles I think I am even more confused. If I understand correctly ETTR only makes sense if shooting raw and not 8bit, is that correct? Since I am not shooting raw where does that leave me, ETTR , expose in the center or ETTL and does picture style make any difference when setting exposure? If I am using a "neutral" or "flat" picture style would I set my exposure using that picture style or set exposure with a standard style and than shoot "neutral"? Thanks in advance.
@newsense.
When shooting in JPG or H.264 where post processing is destructive, I would recommend shooting with the correct exposure (0EV on the meter) in camera.
Excellent thread! I guess this is why cameras like the Red uprate their preffered operating ISO? Around 800ISO at the moment from memory.
@audionut
Very nice info. Why not make a frontpage article from this nice info and show this great new feature to the public. I can help you with that if needed.
Thanks bart. It was RenatoPhoto who got the thread started with another excellent OP.
My biggest issue with tackling something like this is making it legible for new users. And of course, finding the time to compile all the information. It's a rather large topic that requires some brief descriptions of lots of related subjects. I'll ask DXO if we can use a couple of their graphs, if they answer yes, it will give me some incentive to get in and get it done ;)
Yes I see that now. And I see RenatoPhoto, squig and you are doing a fine job with forum maintenance and build testing. Very nice.
Thank you for the information. Great job!
I tried to activate this feature on my 5D3 but it is not available in the Expo menu. Any idea?
Does the feature work in the RAW video mode as well?
Thanks for the help.
Quote from: Audionut on May 27, 2013, 05:01:37 AM
And at 6.4% light level, ISO 6400 has a SNR of around 18dB vs the 6dB of the same shot at ISO 100. Yes, the highlights and midtones will have a higher noise level (lower SNR), but our shadows (where lets face it, all the noise actually is, or more correctly, where the noise is noticeable due to low SNR) OMG.
Interesting read, thanks, but for your general conclusion, I'm not so sure. I understand you're saying that a higher SNR in the shadows is more important than in the midtones (where do the midtones start?). I say this heavily depends on the scene, because probably the shadows won't be important at all, in the background or even clipped by postprocessing to get more punch, while noisy midtones might bother much more if they are smudged by noise reduction.
Also the color rendition goes downhill with higher iso, that's why I'm still not so sure if a properly/ettr exposed shot @iso1600 something on the 18mp sensor is always better than iso800 underexposed. Plus of course if the lighting changes you'll quickly run into blown highlights when you're exposing for ettr, while some underexposure gives a safety margin.
Quote from: Audionut on June 04, 2013, 04:04:55 AM
@newsense.
When shooting in JPG or H.264 where post processing is destructive, I would recommend shooting with the correct exposure (0EV on the meter) in camera.
Not arguing your point but what uses do the waveform and histogram have if canon's EV meter is the best exposure tool? I just shot 4 videos. One exposing at 0EV on Canon's EV meter, one using ETTR making sure not to clip any RGB channels or luma using ML histogram, one using ETTR making sure not to clip luma using ML histogram and one using the ML histogram and exposing in the center. All were shot using neutral PS and before CC they don't look that much different besides the one where I used ETTR and made sure not clip any RGB channels, that one looks pretty underexposed. Maybe after CC I can come up with the best way to expose.
WOW! Thanks for all this information its been so helpful for video (i'll get to using it for pictures soon).
It really improves the footage!
Quote from: newsense on June 07, 2013, 02:27:09 AM
Not arguing your point but what uses do the waveform and histogram have if canon's EV meter is the best exposure tool?
It's not. But if you want to
limit yourself to JPG/H.264, them's the brakes. (http://www.urbandictionary.com/define.php?term=Them%27s%20the%20breaks)
Quote from: newsense on June 07, 2013, 02:27:09 AM
where I used ETTR and made sure not clip any RGB channels, that one looks pretty underexposed
You should brush up a little on exposure and how to read a histogram. There was a strong highlight in your scene that was triggering the overexposure warning in the histogram, causing the overall scene brightness to be low.
If you can retest with the same scene, enable zebras so you can see exactly what is being overexposed. Use the same settings as the Canon exposure meter (0EV) and have a look at what's being overexposed. Determine if that highlight is important. If it is, then technically, ETTR was not underexposing, the Canon metering was overexposing. If that highlight is not important, keep adjusting exposure until an important highlight does start overexposing.
Quote from: Audionut on June 07, 2013, 06:20:53 PM
It's not. But if you want to limit yourself to JPG/H.264, them's the brakes. (http://www.urbandictionary.com/define.php?term=Them%27s%20the%20breaks)
You should brush up a little on exposure and how to read a histogram. There was a strong highlight in your scene that was triggering the overexposure warning in the histogram, causing the overall scene brightness to be low.
If you can retest with the same scene, enable zebras so you can see exactly what is being overexposed. Use the same settings as the Canon exposure meter (0EV) and have a look at what's being overexposed. Determine if that highlight is important. If it is, then technically, ETTR was not underexposing, the Canon metering was overexposing. If that highlight is not important, keep adjusting exposure until an important highlight does start overexposing.
Thanks for responding. Exposure seems to be a problem for me since I got my DSLR. Mainly due to a lot of conflicting information i've came across. I would shoot RAW but I only have a 650D so I am limited to H264 for now. I guess my biggest misunderstanding is should I expose based on luma or RGB? I read somewhere that even if luma channel isn't clipping individual RGB channels clipping can throw away color data. I understand what you mean by only worrying about important highlights clipping, I generally ignore clipped bright windows. From your response I assume you suggest ETTR based on readings from the ML histogram rather than the canon EV meter? Sorry if my questions seem a little noobish but I am fairly new to DSLR and thanks for your time.
@Marsu42
First of all, I'd like to point out that life is a compromise.
I honestly am not sure, on how best to communicate with you. So I'll just be me, and if you take offense at my responses them's the brakes. (http://www.urbandictionary.com/define.php?term=Them%27s%20the%20breaks)
Quote from: Marsu42 on June 06, 2013, 08:50:55 PM
I say this heavily depends on the scene, because probably the shadows won't be important at all, in the background or even clipped by postprocessing to get more punch, while noisy midtones might bother much more if they are smudged by noise reduction.
Generally (most of the time) my exposures are in the higher part of the histogram (ETTR for the win), as I generally don't shot scenes with a large dynamic range, in which case, yeah, I don't give a shit about the shadows either.
But I respect that
some other people do appreciate having clean shadow detail.
I explained reasonably clearly I thought, how the Signal to Noise Ratio worked through the exposure. It makes sense (to me at least) that if you value your midtones more importantly, you would adjust your settings appropriately. The same goes for,
Quote from: Marsu42 on June 06, 2013, 08:50:55 PM
Plus of course if the lighting changes you'll quickly run into blown highlights when you're exposing for ettr, while some underexposure gives a safety margin.
If you place a higher priority on your highlight detail, you would adjust your settings appropriately in this situation also.
Also, I used the shadows in my example as they show a greater benefit with ETTR. Midtones also show a benefit with ETTR. This much should be obvious in the samples crops in my post above. Those crops aren't of extreme shadows ;)
You're trying to find flaws in my specific examples referencing all manner of different situations. A little of the grey matter is needed.
This isn't a guide on exposure, histograms, how to take a photo. It's a guide on how to push your exposure to the right, and the benefits that can be obtained through this practice. Some prior knowledge of exposure is needed.
Quote from: Marsu42 on June 06, 2013, 08:50:55 PM
Also the color rendition goes downhill with higher iso, that's why I'm still not so sure if a properly/ettr exposed shot @iso1600 something on the 18mp sensor is always better than iso800 underexposed.
Look at the data. Bear in mind that the data for ISO 1600 only goes to a luminance of 70, and it's logical to assume that as the color accuracy increases from luminance 30 through 70, it continues to increase through luminance 100.
(https://dl.dropboxusercontent.com/u/34113196/Camera%20stuff/ETTR/ISO800.PNG)
(https://dl.dropboxusercontent.com/u/34113196/Camera%20stuff/ETTR/ISO1600.PNG)
Quote from: newsense on June 07, 2013, 06:38:14 PM
Thanks for responding. Exposure seems to be a problem for me since I got my DSLR. Mainly due to a lot of conflicting information i've came across. I would shoot RAW but I only have a 650D so I am limited to H264 for now.
Everyone has an opinion ;) I would highly recommend that you shot raw photos though. With non-destructive editing, it's much easier IMO to see the effects of exposure changes. And if you want to ETTR, you really have no other choice then to shoot raw.
Quote from: newsense on June 07, 2013, 06:38:14 PM
I guess my biggest misunderstanding is should I expose based on luma or RGB? I read somewhere that even if luma channel isn't clipping individual RGB channels clipping can throw away color data.
I would recommend RGB as it's more accurate. The luma reading sort of mixes all the channels up and gives you an overall exposure reading. As you read, it can often show no over exposure warning when in fact, one of the RGB channels has indeed clipped.
Quote from: newsense on June 07, 2013, 06:38:14 PM
From your response I assume you suggest ETTR based on readings from the ML histogram rather than the canon EV meter?
ETTR is much much easier to do when you understand the histogram. It can be done with the Canon meter, but takes some testing to determine where on Canon's exposure meter, overexposure happens.
Exposure is quite a detailed subject. There are plenty of good resources out there you can read to help increase your understanding (and honestly, they'll probably explain it a lot more accurately and understandable then I can). You really need to understand it better before attempting to ETTR. IMO, you will just confuse yourself further.
Some good reading.
http://www.luminous-landscape.com/tutorials/understanding-series/understandexposure.shtml
http://www.luminous-landscape.com/tutorials/understanding-series/understanding-histograms.shtml
Feel free to fire off more questions. I'll do my best to answer them as clearly and understandable as possible :)
I guess my only question right now is since I am shooting H264 is my best bet for trying to get a good exposure to use ML histogram set to RGB and try to expose to the center? I will most likely have questions after I follow the links you posted
IMO yes. Any editing done to a h.264 stream will be destructive. So the benefits of ettr can't be exploited.
I would recommend using the Canon exposure meter until you have a good understanding of the histogram.
For the purposes of ETTR in raw video... could a picture profile be created to display a lower exposure (so clients don't freak out when they see everything is "blown out").
Dave
Look in image finetuning -> digital ISO. In raw video, it will only affect the preview, not the recorded image.
Quote from: Audionut on June 07, 2013, 06:49:25 PM
You're trying to find flaws in my specific examples referencing all manner of different situations.
Not at all, I was just commenting that your theory "The shadows are where all the action is" is not a general truth, but you just ack'ed that yourself and maybe I misunderstood what you were trying to say.
But this matter is very important to me, because with my 60d I always struggle between underexposing iso800 (with the added benefit of preventing clipped specular highlights) or properly exposing something between iso1000 and iso1600. And my personal observation from the past seem to square with your observations as I understand them: higher iso gives noisier midtones but cleaner shadows, so unless I expect to raise the shadows in post I'm usually sticking with iso800. But I'm very open to suggestions :-)
Also this thread is important to tell two different uses of ettr from each other that might be confused:
1. properly expose for max. use of the available dynamic range, i.e. collecting *more* photons
2. collecting the *same* amount of photons but at different iso levels
Quote from: Audionut on June 07, 2013, 06:49:25 PM
Look at the data.
Interesting - where did you get that from?
Quote2. collecting the *same* amount of photons but at different iso levels
Here it's all about the analog amplifier between the sensor and the ADC. If that amplifier is less noisy than digital gain (e.g. multiplying underexposed data by 2), you can start thinking to increase the ISO.
For digic 4, the analog amplification from ISO 1600 to 3200 is just as noisy as the digital one, so there's no point in going above ISO 1600.
Sure, by raising ISO you lose some dynamic range. You increase ISO by 1 stop => you lose 1 stop of DR from ADC saturation and you gain less than 1 stop of DR because of cleaner shadow noise. So, if you can increase shutter or aperture, do that first (because you don't lose DR by doing that, you just shift it).
But if you have more DR than your scene needs, you can throw away some of it, and increase ISO to get better results.
I recommend reading this: http://www.guillermoluijk.com/article/isos5dmkii/index.htm
Quote from: Marsu42 on June 08, 2013, 12:02:36 PM
Not at all, I was just commenting that your theory "The shadows are where all the action is" is not a general truth, but you just ack'ed that yourself and maybe I misunderstood what you were trying to say.
Shadows are where the biggest gains will be made, as they are closet to the camera noise floor. I tried to emphasis this point, as there are a large number of users who appreciate clean shadows. I guess it's sort of easy to keep your midtones clean, as they should be fine if you have a good exposure (not necessarily ETTR), and the highlights, unless you are severely underexposing them, they will almost always be clean, because they are at the right hand side of the histogram (where SNR is best).
So, to put it differently, any ol tom dick and harry (http://idioms.thefreedictionary.com/any+Tom,+Dick,+and+Harry) can make clean highlights and midtones, getting your shadows clean is where the
real challenge is.
I was honest when I stated that an understanding of exposure is needed to fully appreciate ETTR. That's not directed at you personally, it's a general statement that I wanted to revisit. In fact, I'd go as fare as to say, to fully appreciate ETTR, you also need a good understanding of your cameras sensor response (how it responds to light), and it's noise characteristics.
Quote from: Marsu42 on June 08, 2013, 12:02:36 PM
But this matter is very important to me, because with my 60d I always struggle between underexposing iso800 (with the added benefit of preventing clipped specular highlights) or properly exposing something between iso1000 and iso1600. And my personal observation from the past seem to square with your observations as I understand them: higher iso gives noisier midtones but cleaner shadows, so unless I expect to raise the shadows in post I'm usually sticking with iso800. But I'm very open to suggestions :-)
It's important to point out that highlights are the brightest parts of the scene. Whether that is a candle or the sun. Then from there, the midtones are around 18% of those highlights, and from there, the shadows extend down to pitch black.
By attempting to retain specular (https://en.wikipedia.org/wiki/Specular_highlight) highlight detail, you are increasing the dynamic range requirements of the camera by a
spectacular ;) amount.
Cameras have a limited ability to capture bright whites and dark blacks (dynamic range). If you are attempting to shot a scene with a dynamic range in excess of that of your camera, no amount of ETTR is going to help.
I can blabber on with fancy graphs and fancy dB readings all day long, but the best way to understand your camera, and the benefits of ETTR is to go and try it.
Find a scene with a limited dynamic range to test, as this will highlight the benefits of ETTR. From there you will have a better understanding on how ETTR and dynamic range interact.
A bare wall very slightly out of focus is a good test. Noise is more prominent (http://www.thefreedictionary.com/prominent) where detail is less.
Noise can actually increase the perceived detail when viewed at sufficient viewing distances. Anyway, that's a different topic :)
Shot @ ISO 800 @ 0EV on the Canon meter. Then increase ISO to 1600 and reduce shutter speed until you start to overexpose the image. I also recommend using RawDigger (http://www.rawdigger.com/) to determine true overexposure in the shot. Or thanks to the absolutely marvelous advancements with ML, use the Raw histogram in LV for quicker results.
Take a look at both images. The ISO 800 shot we'll call underexposed (even at 0EV on the Canon meter), and the ISO 1600 shot we'll call ETTR. Which one has the least noise? Cameras generally have around 3EV of highlight headroom (detail capturing ability above 0EV), so take a shot @ ISO 400 @ 0EV on the camera also. Compare it to the ISO 1600 shot. Which has less noise? ;)
It all boils down to how much dynamic range the scene contains, and where 18% (middle grey) (or 12% or 13%, take your pick (https://www.google.com.au/search?q=camera+middle+grey&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a)) of the overall luminance level of the shot is. With a large dynamic range scene, 0EV on the Canon meter is going to be accurate, because it's got lots of detail (data) to determine precisely where the correct (18%) exposure is.
On scenes with limited dynamic range, there often might not be enough detail (data)/(information) for the camera to determine where a correct exposure is. And it will tend to underexpose, or, more precisely, not push the exposure to the right hand side of the histogram where the sensor is performing at it's best. In this case, ETTR will net you a much better (cleaner, and more accurate color rendition) shot of the scene.
As a1ex points out, best case is using shutter and/or aperture to push the exposure to the right. You're increasing the photon capturing ability of the sensor, without all the side effects that come from increasing that sensitivity via analog gain (ISO).
But if you take a look at the sample images I posted on page 1 of this thread, I show where ISO can be increased, and results in less overall noise in the photo. Noise increases
constantly with analog sensor gain (lower ISO's),
but, noise
decreases exponentially with increased luminance (in the shadows at least, the roll off is less at higher luminance levels).
Quote from: Marsu42 on June 08, 2013, 12:02:36 PM
Interesting - where did you get that from?
DxOMark (http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Database/Canon/EOS-60D).
The link a1ex gave above makes for good reading.
Note: There's some words in there with links to meaning. This isn't directed sorely at you, but is included for the benefit of other readers, particular those without English as their first language.
a1ex pointed out in another thread that you can use image finetuning to display the "correct" exposure on the display in liveview without affecting the raw recording.
I tried shooting an h.264 this way, and the .mov file was tuned correctly... without noise!
So it seems this can be applied to h.264 recording as long as you're tuning the image correctly in camera.
Right, the digital ISO from image finetuning is effectively exposure compensation applied "in post" (after the raw data has been captured). But since it's applied before H.264 compression, it can help a lot.
I've pointed this out one year ago I think, but it got buried in the google groups :P
A little scratchpad (feel free to polish it, fix mistakes and turn it into a nice article): http://magiclantern.wikia.com/wiki/ISO . That one represents my opinion from one year ago, so take it with a grain of salt.
I'm sorry to ask for more of an explanation after such in depth descriptions, but I'm still left with questions.
With auto ETTR on, it is controlling ISO and shutter, meaning if I try to change either it automatically replaces it where it thinks it should be. So, is the only adjust to make the % of highlight to ignore?
Is the idea to get the White # inside the histogram to balance out to 0?
When ETTR is on, and the image is still underexposed, I'm assuming it's because I have a blown out window in the frame (for example). Is this correct? If so what is the correct procedure to compensate?
I'm currently uploading some video I shot with ETTR to show you where I'm at. I'll add it as soon as its uploaded.
Thanks for the help.
Quote from: duncanidaho25 on July 10, 2013, 02:57:52 AM
With auto ETTR on, it is controlling ISO and shutter, meaning if I try to change either it automatically replaces it where it thinks it should be.
AutoETTR adjusts shutter/ISO only. Aperture is left for the user to control.
Depending on settings (AutoETTR), if you adjust shutter/ISO, AutoETTR will adjust the shutter/ISO again.
Quote from: duncanidaho25 on July 10, 2013, 02:57:52 AM
So, is the only adjust to make the % of highlight to ignore?
Also the exposure target. IIRC, this determines how close to full saturation to ETTR.
And clipping mode. You can clip the green channel for instance and recover the lost detail from that channel in post processing.
Quote from: duncanidaho25 on July 10, 2013, 02:57:52 AM
Is the idea to get the White # inside the histogram to balance out to 0?
Digital cameras have a maximum pixel saturation. After pixel saturation (blowout/clipping), detail is lost.
ETTR is about pushing the exposure as bright as possible without saturating the pixels.
Quote from: duncanidaho25 on July 10, 2013, 02:57:52 AM
When ETTR is on, and the image is still underexposed, I'm assuming it's because I have a blown out window in the frame (for example). Is this correct? If so what is the correct procedure to compensate?
Correct. You can adjust highlight ignore to try and compensate for specular highlights (or other detail you don't mind being blown), otherwise you are left to manually adjusting the exposure as needed.
Raw based zebras will show the areas of overexposure (pixel saturation). Use these to determine if wanted detail is being blown.
With your blown out window frame for example, AutoETTR is trying to maintain all detail (subject to it's settings), but since the window frame retaining detail is resulting in underexposure of your scene, you could use raw zebras to keep increasing exposure as desired while monitoring wanted detail to ensure it's not being blown out.
Here's me trying to figure out ETTR. https://vimeo.com/69923344
I processed using:
RAW2CDNG
Resolve - with Hunter's LUT (https://vimeo.com/67970827)
exported as QT 4:4:4
I then played around with the colorgrading (colorista, fast color corrector) I probably would have been better off just to leave it as is though.
then exported h.264
I noticed some heavy aliasing (on the medicine bottles) that vimeo introduced. (I think I exported with the wrong settings for vimeo).
*Side note, watch out that in 3X crop mode that you shoot in the middle of your frame. As you can see I was too far left on a few shots.
Anyway, as you can see I'm struggling getting the correct exposure. I'll try again after your response. (Thanks by the way).
I have yet to install ML onto my camera but interested in both Auto-ETTR and raw histograms.
Is there any way to have Auto-ETTR and Raw histogram features when shooting still images without using live-view? I typically shoot using AI Servo mode tracking subjects where using live view is not an option.
Ideally, the raw histogram would replace the jpg histogram when reviewing images and the Auto-ETTR hint would be visible in the viewfinder when shooting in Manual Exposure mode telling you how many EV you are off.
In photo mode, Raw based histograms/zebras/spotmeter only work in quick review (the image shown immediately after a shot).
If you press the play button to view images, these will not have raw based histograms/zebras/spotmeter.
Each line in the raw histogram represents 1EV. You can also enable ETTR hint which will give you a numerical value of how far EV is from maximum.
AutoETTR works in photo mode just fine. Here you adjust trigger mode in AutoETTR settings. Always ON will adjust the camera settings after taking a reference pic, and will continue to adjust settings as needed for all shots. Auto Snap will take consecutive shots until the best settings are found. Press SET allows you to press the SET button to engage liveview and find the best settings. The same also applies for HalfS DblClick, obviously this will happen with a double press of the shutter rather then the SET button.
No Magic Lantern information is available through the viewfinder.
If you need visual confirmation through the viewfinder of the best ETTR settings, your only choice is the Canon exposure meter at the bottom. Put the camera in manual mode with SPOT metering. Find a plain wall. Adjust settings so that the Canon exposure meter is showing +2EV. Take a shot and inspect the photo with a raw utility such as RawDigger (http://www.rawdigger.com/), or the raw based data from Magic Lantern.
Is there overexposure? There should not be. In which case, adjust settings so that the Canon meter shows +2.3EV, take another test shot. Continue until you find the Canon meter reading which starts to result in overexposure. This should be around +3 to +3.5EV.
If +3EV is the maximum Canon meter reading that results in no overexposure of your shot, you have found how to manually ETTR with the Canon meter.
Stick in spot meter mode and use your spot meter to judge exposure. Taking a landscape, spot meter off a bright cloud at +3EV. Done!
Doing a wedding and want to ensure the white dress is the maximum luminance and retains detail. Spot meter it at +2.6EV (leave a little headroom). Done!
Want to nail a correct exposure of a pale skinned person, spot meter them at +1EV. Highlights will fall where they fall, shadows also. But the skin will be correct ;)
Here is my ETTR test:
I probably should have tested without the motion. It wasn't very smooth, and even warp stabilizer didn't salvage it.
I did 5 shots. I used the AUTO ETTR settings for shots 1 & 3, the others I did not use the settings suggested ( I used the 2 times half shutter mode).
Can someone help me understand how to read and use the E # and RGB #s.
I did grade these. I guess I should have left them alone for a more accurate test. Again, Thanks for your help!
**also, how do you use vimeo video embedding correctly in this forum?
SETTINGS for the 5 shots:
Shot 1:
ISO: 800
Shutter: 48
fstop: 2.8
ETTR= 1.4 R-1 G-4 B-2
Shot2:
ISO: 100
fstop: 2.8
shutter: 48
ETTR=4.1 RGB = _ _ _(all blank)
Shot 3
ISO 800
Shutter: 48
fstop 2.8
ETTR= 1 RGB=264
Shot 4
ISO: 1600
fstop: 5.6
shutter: 48
ETTR=2.0 RGB=121
Shot 5
ISO 100
fstop 1.4
shutter: 48
ETTR= 2.7 RGB= _1_
Quote from: duncanidaho25 on July 22, 2013, 01:42:14 AM
**also, how do you use vimeo video embedding correctly in this forum?
You need to remove the s from https and embed the link in the vimeo tags. I've edited your post. Click the modify button on your post and check how I've done it.
What exactly is it that you're trying to test? I understand your using ETTR, but how? What do you want it to accomplish?
Where are you getting these ETTR and RGB numbers from?
I'm just trying to understand how to use the Auto ETTR module. I'm only trying to accomplish good exposure and get the wide dynamic range I should get with shooting raw.
I got the numbers from the RAW histogram in Magic Lantern.
Inside there is a Red#, Green#, Blue# and a "White E#"
Thanks for the embed tip. I've got it now.
Quote from: duncanidaho25 on July 22, 2013, 03:56:38 AM
I got the numbers from the RAW histogram in Magic Lantern.
Inside there is a Red#, Green#, Blue# and a "White E#"
The RGB numbers represent the percentage of overexposure in each channel. So for instance, Green 4 is reporting 4% of the pixels in the green channel have become white (overexposed).
The White E represents the amount of EV until overexposure. Or the amount of
-EV for no overexposure.
Quote from: duncanidaho25 on July 22, 2013, 03:56:38 AM
I'm just trying to understand how to use the Auto ETTR module. I'm only trying to accomplish good exposure and get the wide dynamic range I should get with shooting raw.
AutoETTR is only helping with the white (brightest) point of your exposure. If you have a scene with a low dynamic range (difference between brightest part of the exposure, and darkest part), AutoETTR will be extremely useful as it will push the exposure to the right, and the camera will capture the scene with the highest Signal to Noise Ratio and best color rendition.
On scenes with large dynamic range, things get a little more complicated. Do you want a bright light to remain exposed (not pushed to white), which will underexpose the rest of your scene, or do you want to ensure the correct exposure for one part of your scene (skin tones for example), which will result in other parts of the scene becoming overexposed.
AutoETTR doesn't know what you want. All it's doing is ensuring that nothing gets overexposed (within the limits of its settings). You need to make a conscious decision on what to do with your exposure.
On scenes with large dynamic range, use the Zebras. Zebras will show what areas are being overexposed, and what areas are being underexposed and pushed into the noise floor of the camera. This will allow you to make the best decision on what to do with the exposure.
This is a big help. Thank you.
Thanks for the info Audionut!! Do you know how long the camera takes after each shot to process the Raw histogram? Would enabling raw histograms be practical when shooting an event where you are shooting many consecutive frames using AI servo mode? I noticed that in a different thread, you have asked for the priority of the raw histogram to be lowered to allow the camera to be responsive more quickly.
I would guess that Auto-ETTR might not be practical as it may do several shots back to back and then evaluate what exposure is ideal in that situation.
Quote from: ronl on July 24, 2013, 09:54:15 PM
Thanks for the info Audionut!! Do you know how long the camera takes after each shot to process the Raw histogram? Would enabling raw histograms be practical when shooting an event where you are shooting many consecutive frames using AI servo mode? I noticed that in a different thread, you have asked for the priority of the raw histogram to be lowered to allow the camera to be responsive more quickly.
To be fair, it was only a very narrow period (of time) where shooting became unresponsive. a1ex has recently fixed it. Raw histogram no longer effects shooting response.
Quote from: ronl on July 24, 2013, 09:54:15 PM
I would guess that Auto-ETTR might not be practical as it may do several shots back to back and then evaluate what exposure is ideal in that situation.
It will only take consecutive shots when the trigger mode is set to Auto Snap.
It may need several shots to settle on accurate settings.
Like everything, it has it's uses, but is not the be all and end all of correct exposure ;)
Audionut,so if i have the camera on tripod for landscape photography,I just have to choose press SET and that will calculate the exposure?Correct?
Been using ETTR for a few days... do not use for portraits if your background is bright like the sky/sunny... ETTR will try to expose for sky/highlights and your portrait will be recoverable but the result is horrible.
@ouuzi
You can trigger the ETTR calculation as you see fit. The end result will be the same.
@ShootingStars
That's been explained in this thread already. AutoETTR only considers the white point!
I read the thread, but can't seem to find a confirmation of this. It seems the ETTR module works only by changing the ISO and shutter speed, is that correct? Or is there a way to make it set the aperture (and ISO)?
Thanks
It does not adjust aperture at all.
AutoETTR will use lowest ISO as priority, and then adjust shutter speed as required. You can set the slowest shutter speed used in the AutoETTR menu.
If you need to force a slow shutter speed, you can either increase aperture manually, or control exposure entirely yourself.
Thanks for the detailed steps.
I have a question about the Trigger mode.
What's the meanings of Always ON Auto Snap, Press SET, HalfS DblClick?
For "press set", I understand it. When press set button, the camera will change to liveview automacticly. And measure how to adjust the iso or shutter, then return to the normal mode, let you to take pictures.
For "auto snap", it seems that when you finish one picture taken, ML will calcurate this picture to get the params, and then trigger another shoot automacticly(Am I right?).
For always on and halfs dblclick, I'm getting confused.
Halfs dblclick, does it means that I point the camera to the subject, and click the shutter button half twice. Then ML will calcurate the params, wait for seconds, I can click the shutter button fully to take the picture?
Thanks and sorry for these questions
That's correct tankvps.
And always on means that it continually calculates the exposure based on the previous shot.
Quote from: Audionut on August 18, 2013, 02:18:17 PM
That's correct tankvps.
And always on means that it continually calculates the exposure based on the previous shot.
Thanks.
But for Halfs dblclick, After I half click the shutter button twice, and then full click to shoot, no magic happens. How long should we wait for the calcuration?
Double click half shutter should produce the same actions as the set button option.
I am having a problem with the slowest shutter speed.It keeps changing.I shoot landscape and I need the ISO to 100,so usually I set the slowest shutter speed to 32" since I do not mind because of the tripod.Is there a way to make ML to remember the settings?
Does it change in the ETTR module, or when shooting?
It does change in ETTR module settings.I have kept it at 32" but yesterday I tried to shoot some landscapes and because the shutter speed was set at 1/2 by it's own ,it increased the ISO to get proper exposure.
Hi ETTR guys.
I must be doing something wrong...
I tried ETTR on my 7d and followed the instructions from the first page of this post.
But I get a wrong result : exposing to the left.
An example :
- first picture 1/60, 4,5, iso 400, Manual mode, ETTR always on -3EV. The exposure is normal and the histogram center and left
- second picture calculated by the 7d : 1/250, 4,5, iso 100. The histogram is completely on the left.
Shouldn't it be the contrary and the 7d shouldn't have calculated an over exposition like 1/60, 4,5, iso 800 or more ?
I'm completely confused.
Thierry
You have to set how many highlights you are willing to clip.
The values are :
Trigger mode : always on
Exposure target : -3EV
Highlight ignore : 0,2%
Clipping mode : no clipping
Slowest shutter : 1/44
The rest : OFF
Thierry
QuoteExposure target : -3EV
Read the help ;)
Ok, I tried with -0,5EV, 0,2% Highlight ignore, no clipping, Slowest shutter 1/8.
I took a picture Iso 400, 1/125, 5.6. The histogram is centered.
The second picture with the ML settings was exactly the same,
The third one was 1/250, 5.6. The histogram is on the left with a pike on the right. The +/- ont he top of the screen shows -1, and when I go on the Quick menu of the 7d, The exposure correction shows -1.
And when I go to the Canon Menu the Exposure correction has been modified to -1 (I've never changed that value !). When I put this value to 0 and I take pictures with ETTR on, the value is modified to -1.
Thierry
Let it ignore more highlights, maybe let it clip some channels too. Or shoot something with less dynamic range.
Or set the SNR limits if you use a recent version.
I'll try tomorrow in the sun.
Thierry
I'm using Auto ETTR on 50D. This build (https://bitbucket.org/andy600/tl50d/downloads/Tragic.Lantern-2.0-Andy600.Build.2013Aug27.50D109.zip), based on Tragic Lantern 2.0, makes it possible to use Auto Snap feature and does not require entering LV mode. Normal nightly builds (checked yesterday) won't do it.
1. What is different between these builds? I see Tragic Lantern is merged into nightlies from time to time (later than the mentioned build anyway).
2. Quite often I see "exposure out of range" (or similar) message. A1ex mentioned that it's possible to use Auto-ETTR in very low light conditions (cave - http://www.magiclantern.fm/forum/index.php?topic=6554.msg59368#msg59368) outside LV. What else is needed to get 50D to work in larger range? It is larger than old builds now, but still I can't use it in low light (not to mention caves) or in bright scenes.
Quote from: akumiszcza on September 05, 2013, 07:34:03 AM
I'm using Auto ETTR on 50D. This build (https://bitbucket.org/andy600/tl50d/downloads/Tragic.Lantern-2.0-Andy600.Build.2013Aug27.50D109.zip), based on Tragic Lantern 2.0, makes it possible to use Auto Snap feature and does not require entering LV mode. Normal nightly builds (checked yesterday) won't do it.
The main development line has those features. Check the OP of this thread ;)
Quote from: Audionut on September 10, 2013, 02:55:16 AM
The main development line has those features. Check the OP of this thread ;)
I don't see anything in opening post about this. Settings are fine, the same for TL50D build and nightlies. Auto Snap just doesn't take another photo on my 50D in nightly build (at least several days ago). Or maybe is there a place where I can download newest ettr module alone?
Quote from: akumiszcza on September 05, 2013, 07:34:03 AM
1. What is different between these builds? I see Tragic Lantern is merged into nightlies from time to time (later than the mentioned build anyway).
I dont know specifically what is different but each developer can be testing or using different code that can make the camera behave differently. When a code is acceptable to be merged with the unified then it will show up in the nightly build.
http://builds.magiclantern.fm/#/
Quote from: Audionut on September 10, 2013, 03:01:13 PM
http://builds.magiclantern.fm/#/
I know where nightlies are, Audionut. Anyways I've downloaded latest 50D nightly just now and always on/auto snap does not work. They work fine in two last TL builds. I'm just saying there is something there that should be probably included in main builds.
Quote from: RenatoPhoto on May 25, 2013, 07:24:06 PM
Updated September 15th 2013..
In case that you know nothing about ETTR then go read here:
http://www.luminous-landscape.com/tutorials/expose-right.shtml
and then here:
http://www.luminous-landscape.com/tutorials/optimizing_exposure.shtml
The luminous-landscape information was provided thanks to Michael Reichmann.
Wow! Lovely articles. Thank you for posting the links.
I am noticing a slow down of ettr in the latest build.Is something changed ?I am using 5/10 build and I have set the trigger to Halfs DBC, I was using this till now.After double click it takes noticeably more time to end calculations(it goes to ettr(5) if this makes a difference),I have also noticed that I see something like a thin line of pixels scanning down the screen from top to bottom.
My setting are:
Defaults all except link to dual iso and SNR limits off both.
http://www.catb.org/esr/faqs/smart-questions.html#beprecise
Quote from: ouuzi on October 05, 2013, 10:05:47 PM
I am noticing a slow down of ettr in the latest build.Is something changed ?I am using 5/10 build and I have set the trigger to Halfs DBC, I was using this till now.After double click it takes noticeably more time to end calculations(it goes to ettr(5) if this makes a difference),I have also noticed that I see something like a thin line of pixels scanning down the screen from top to bottom.
My setting are:
Defaults all except link to dual iso and SNR limits off both.
As for this scanning – I've noticed it in October 3 nightly (see this post http://www.magiclantern.fm/forum/index.php?topic=8322.msg80410#msg80410) and it was connected with RAW zebras I think. Sometimes almost all of the photo was overlaid by it, as you can see in the screenshot there. Anyway, the problem disappeared in later nightly for me.
I picked up a 50d a few days ago and the zebras are borked. Histogram seems accurate though.
When I get some time I'll have a look.
The only time I have noticed AETTR being slower is when the debug/show metered areas options are enabled. This is to be expected afaik.
I just updated to the latest build by a.d. for 5d2, A. ETTR module is loaded but it appears grayed out, what can be the reason? I have tried all sorts of settings but can't seem to get it to work...
EDIT: Please ignore the above... image quality was set to jpg for RAW recording...
I shoot a 5DM2 & am trying to get into this AutoETTR thing ~ The 5d seems to be going through the paces ie when I press the SET Button it Beeps, the Mirror & Shutter sequence, followed by another Beep ~ But ~ the Exposure that I take next does not ETTR ~ anybody have any ideas ~ I'm guessing I'm doing something wrong just don't know what.
ORR ~ DeanB
Hi there
I am a new ML user and a bit lost in regards to versions and modules loaded.
RenatoPhoto wrote in his post on 2013-05-26, 03:24:06
>>>>
Are you ready for the easy stuff now?
ETTR in RAW images - Camera Options available
This functionality has been ported to all of the supported cameras.
PLEASE BE ADVISED THAT THESE MODULES ONLY WORK IF YOU HAVE ENABLED THE BOOTFLAG IN YOUR CAMERA.
If your camera has these features then you will find them here:
In the Expo Tab (Exposure Menu of ML) you will find Auto ETTR. For this to work you must be in Manual mode and also the ISO must be in manual. If you meet these requirements you will be able to enable it by pressing the Set button (depends on camera).
<<<<<
Am I right in assuming that a daily build after Magic Lantern v2.3 has to be loaded to actually display ETTR functions in the Exposure Tab?
Thank you in advance
You are correct.. you must use a Nightly build after ML 2.3. Copy the nightly files over and you'll be good to go.
Quote from: RenatoPhoto on May 25, 2013, 07:24:06 PM
[...]
RAW histogram on the bottom right is a small graph.
a. Inside this histogram you may see near the top-left of the graph, in white lettering, the letter E followed by a number which represents how far you can go, in EV numbers, to reach ETTR, i.e E1.2
[...]
I did a quick test on 6d and I cannot see the 'E', only R/G/B are there. I used TL zip from NOV09, any hint?
You must load the module and shoot in RAW !
Quote from: vertigopix on November 27, 2013, 04:28:49 PM
You must load the module and shoot in RAW !
OK - must be full RAW mode, not M-RAW/S-RAW.
I extracted the info in the forum threads and added documentation on Auto ETTR to the dokuwiki:
http://wiki.magiclantern.fm/ettr
Feedback welcome!
Nice!
Probably a good idea to have a page like this for most major modules (maybe also for smaller features like zebras?).
Maybe even split the user guide into pages, and then having a master page that collects them all?
(just thinking out loud)
OT: about the image with zebras... how did you get that 3.4GB overlaid on it? (that thing should have been reported as bug)
Hey guys, long time lurker here, just wanted to say the hugest thanks to all the developers on this project, it really is a thing of beauty to see so many people collaborating so selflessly for the benefit of the film-making community.
I'm still trying to wrap my head around ETTR, and can't find an answer anywhere on here -
- When I do auto ETTR by pressing the set button it changes my shutter speed from 48 to 53. Any idea why / how I can keep my shutter speed at 1/48?
If you could shed some light on this, I'd really appreciate it!
Jeb
Edit - I've fixed this with the shutter tweak!
Hey guys! I just tested the ETTR feature on my 5d mark iii and i get a "Raw error" message. Sorry if this has been discussed but i found nothing about this. It doesn't happen always but at least 6/10 times i take a photo with ETTR.
ML last version for 5d 1.2.3
Raw enabled from Canon menu
ETTR Always on (i didn't change nothing else, just followed the instructions)
*In cases that ettr works and i don't get the "raw error" message, the photos get about 3 stops overexposed and all highlights get blown out. Any ideas?
Thanks in advance.
I took around 10000 pictures on 5D3 after upgrading to 1.2.3, most of them with ETTR, and I have yet to see this error message during actual use. A video showing the error and the settings should help.
Overexposure may happen if SNR limits are too high, or - with "always on" outside LiveView - when moving from a dark scene to a bright one, until it converges.
Quote from: D.Stasinos on May 18, 2014, 03:33:08 PM
Hey guys! I just tested the ETTR feature on my 5d mark iii and i get a "Raw error" message.
Do you also have jpeg enabled next to raw? That's the culprit on 6d.
Quote from: Marsu42 on May 19, 2014, 09:04:28 AM
Do you also have jpeg enabled next to raw? That's the culprit on 6d.
No, only raw is enabled.
Quote from: a1ex on May 18, 2014, 08:57:47 PM
I took around 10000 pictures on 5D3 after upgrading to 1.2.3, most of them with ETTR, and I have yet to see this error message during actual use. A video showing the error and the settings should help.
Overexposure may happen if SNR limits are too high, or - with "always on" outside LiveView - when moving from a dark scene to a bright one, until it converges.
A1ex thanks for your feedback. And by the way thanks for all the nice tools you brought to our hands! The first time i got the "raw error" message was when i moved the camera outdoors (i moved from a dark place to a bright one). I am trying to find a certain way to reproduce this cause its a bit random. LiveView is always enabled on my tests.
And a quick question: when i half press the shutter button, is this the moment when ETTR needs some time (3 secs as RenatoPhoto pointed out) to make proper calculations about the exposure?
Today I was in a short trip, so I used ETTR always on in LiveView. I've got "raw error" 3 or 4 times, but I've narrowed down all of them to the changes from this branch (https://bitbucket.org/hudson/magic-lantern/pull-request/484/black-level-fix), which is not included in the nightly builds. So, if you were using the nightly, I still have no clue about how to reproduce the error (it means the raw backend was not available for some reason).
When you press the shutter halfway, ETTR finishes the current iteration and then it gets paused. You will notice a big slowdown if you use the "zoom on half-shutter" option, but I'm going to speed it up.
Hello everyone, another ML first time user here! I've installed it mainly to play around with ETTR. I have a couple of beginner questions; if you can be patient with me as I have not been able to find the information through a search of the forums:
1) It is possible to disable the beeps? (I am thinking of discreet situations when shooting from the hip and trying not to attract attention)
2) Am I right is thinking that this only works in Liveview, i.e. it is not possible to replace Canon's default metering algorithms outside of liveview?
I'm having a lot of fun playing around with ML, so thanks for all the hard work!
Top of page -> User Guide -> FAQ and User Guide.
Quote from: Walter Schulz on June 01, 2014, 01:14:26 PM
Top of page -> User Guide -> FAQ and User Guide.
Thanks, but there is nothing in neither the user guide nor the FAQ about disabling beeps in ETTR. I guess I should clarify by stating that I am referring to the two methods of using the SET button or the half-press to ETTR.
Please correct me if I am wrong.
I'm running ML on 650D and 7D. First one doesn't give sound with ETTR, second does.
Would be fine to have sound confirmation optional.
Good point - I should have said that I am running ML on the 5D mk ii.
Try Audio tab -> Beep, test tones -> Enable Beeps -> OFF
Quote from: Walter Schulz on June 01, 2014, 05:56:38 PM
Try Audio tab -> Beep, test tones -> Enable Beeps -> OFF
Ah, brilliant - thanks! I was just reading the instructions for the ETTR part. Sorry for the bother.
I used AUTO ETTR, Always ON.
Auto Exposure was also ON and I realized that both could not coexist.
When I disabled Auto Exposure, Auto ETTR was working perfectly.
I think this should be handled by ML.
Quote from: Quentin on June 10, 2014, 04:08:17 PM
I think this should be handled by ML.
Since these are both modules, they don't "know" about each other. Perhaps something like a "Conflicts" tag could be added for https://bitbucket.org/hudson/magic-lantern/pull-request/407/module-tags-ratings-wip That could also be used for mlv_rec, raw_rec.
Right, I've tried searching the forums having no luck.
Having read this thread, my understanding on ETTR is that it really shines when recording RAW (highlight recovery etc.) but if the sensor is linear and most colour information is captured at the bright end of the sensor, surely ETTR should be used with H.264 recording as well? Or am I missing something here?
I saw someone commenting that editing H.264 in post is destructive, which of course is the case, but wouldn't using ETTR still produce better results than 'correct' exposure (providing no clipping, or acceptable clipping occurs)? Wouldn't this yield better SN ratio and thus less noise in the shadows for the H.264 too?
And on another note, should ETTR be used if recording to higher bitrate codec (i.e. ProRes 422 HQ) through HDMI?
I mostly shoot video in very controlled environment so knowing this would be helpful.
Thanks,
PJ
The concept of ETTR should be used with H.264, of course, but this ETTR module and it's specific implementation uses the raw histogram and raw data to calculate the clipping level and other things (like SNR levels). If you are doing H.264, that means that the calculation will be incorrect => something that isn't clipped in the raw data, might very well be in the h.264 data.
So, if you're shooting H.264, yes you should "ETTR", you just wont be able to use the AutoETTR module to do that for you automatically. You can do it manually with any of the non-raw exposure aids (like zebras, histogram, spotmeter, etc.)
In H.264, I'd say you should use ETTR only if you find the footage noisy. The exact exposure choice for H.264 can be different from RAW though (you mentioned it - editing 8-bit data after compression is not going to be funny).
A good option would be to ETTR just as you would do in RAW (to maximize the SNR of the input data), then use ML digital ISO (the one from image fine-tuning) to get something close to your final look. In RAW, the digital ISO is ignored (you apply it in post), so ETTR ignores it completely. But for H.264, digital ISO is essential, because it's like an editing step done before the conversion to 8-bit.
A good rule of thumb is to set a full-stop ISO from Canon menu, and set your digital gain of around -0.3 or -0.5 EV. Darkening more than that will create pink highlights (but if you don't have any, or if you can fix them easily in post, just go ahead and darken a little more).
One thing to be aware of - Canon does not use any highlight recovery for JPEG/H.264 (so, depending on your white balance, around 1 stop from red and blue will get clipped). So, the exposure choice for H.264 may have to be a little darker than with RAW.
Excellent, thank you Alex & dmilligan, very helpful!
For recording HDMI to ProRes, would the same principle apply? Or does the ML digital ISO not affect HDMI (I assume it does)?
Does Auto ETTR work real time in Video Mode ?
I dont think so because its a hard procedure that takes time, hard to capture and store at the same time.
When I record video, which is the last valid calculation ?
When I press the Button ?
Thanks for the illumination
It works fine in real time, in video mode. You just may not like the exposure jumps.
Quote from: a1ex on June 11, 2014, 07:28:25 PM
A good option would be to ETTR just as you would do in RAW (to maximize the SNR of the input data), then use ML digital ISO (the one from image fine-tuning) to get something close to your final look.
Never thought of this. :)
And BTW, this thread in 4th on a google search for ETTR, it's probably time I cleaned this sticky up a little.
edit: Oh, I could have sworn it worked the last time I tried it (about 12 months ago :( )
Right now it stops adjusting as soon as you press record - to avoid the exposure jumps.
It can be made to work while recording. However, it will require a deflickering algorithm when extracting the DNGs, or a fast (real-time) algorithm to tweak ML digital ISO on the fly for H.264.
There is real-time access to Canon's YUV histogram data, which could be used for this purpose.
I hope there will be switch for this.
Sometimes you know that you will shoot and the lighting is steady and predictable so dynamic ETTR is not essential.
Sometimes you have a complex shot with cast changes in lighting conditions where a dynamic ETTR is necessary.
Thanks in advance for the Magic!
Big thanks to RenatoPhoto for the original OP, however it was probably a little long in the tooth, and more importantly, outdated.
I have edited down to the specific information, and updated it for the latest changes in the module. Let me know if I have missed something, or made a mistake.
Quote from: ilguercio on May 27, 2013, 07:02:46 AM
Very good thread.
I have been a huge supporter of ETTR during the years as it's another way of making the most out of our cameras.
@audionut: sorry for breaking the thread flow but apparently (from the electronic cigarettes (http://www.ecigfiend.com/) package i see) you are from Australia.
What area?[/color]
Definitely it was pretty nice thread so from which region he belonged?
I have a question. If I use zebras for exposure, technically, can't I achieve the same result and ETTR myself?
Thank you,
Mr D
You can use any of the raw based exposure guides (http://www.magiclantern.fm/forum/index.php?topic=12096.0) and ETTR manually.
@Audionut thank! (From the wrong black Level thread).
I have read all the thread and I will to trust in ETTR!
It's a wonderful tool!
I've been using ML intervalometer to create regular time-lapses (i.e., not day-to-night time-lapse or vice versa; just plain old vanilla ones). After discovering and watching a few time-lapses created by other ML users, I found that they used AutoETTR and ML other features to create their time-lapse. I'm striving to reach their level of expertise and I've been diligently reading the following articles to understand AutoETTR:
http://wiki.magiclantern.fm/ettr
http://www.magiclantern.fm/forum/index.php?topic=5693.0
http://www.luminous-landscape.com/tutorials/expose-right.shtml
http://www.luminous-landscape.com/tutorials/optimizing_exposure.shtml
These articles have been very helpful in helping me (kind of) understand AutoETTR. But all the technical talk has made it very confusing and difficult for a beginner or intermediate DSLR user that has no background in computer science, physics, optics, digital signal processing, etc., (like myself) to fully understand what AutoETTR is, what each ETTR parameter means, how to adjust each ETTR parameter to achieve the desired result, etc. I feel like I need an advance degree just to keep up with the discussion.
So I'm politely asking the ML community and DEVs, please, can someone explain AutoETTR to me in layman terms. I have a Canon 600D and my main focus is to use AutoETTR to shoot time-lapses; particularly, holy-grail time-lapses. I would very much like to create a time-lapse similar to these guys:
https://vimeo.com/100595820
https://vimeo.com/72521286
Here I go with my very basic understanding and questions.
(1) Tigger Mode: From what I gathered through my reading, and for my particular interest (time-lapse), the "Trigger Mode" should be set to "Always On." This feature essentially means that the camera will always analyze its surroundings to adjust the ISO and shutter speed for the next shot. In other words, the camera will take a picture, analyze its surroundings after taking the picture, adjust the ISO and shutter based on the analysis, and take another picture using the new adjustments. These steps are repeated for each shot. Is my understanding correct? And is the camera analyzing its surroundings to adjust the ISO and shutter, or is it analyzing the last picture taken to adjust the ISO and shutter?
(2) Slowest Shutter: As the parameter implies, this is where you adjust your slowest shutter speed. But I'm not completely sure why you need to set your slowest shutter for AutoETTR to use. So, for example, I'm shooting a day-to-night time-lapse. The shutter speed during the day shots are at 1/1000. As the sun goes down, the ISO and shutter speed would be automatically adjusted by AutoETTR to compensate for the decrease in light. The shutter speed eventually reaches 1/16 (i.e., the speed I set for the "Slowest Shutter" parameter). What would reaching my set limit do to AutoETTR? What significance does "Slowest Shutter" have? What does increasing or decreasing the shutter speed do in terms of AutoETTR? What is the slowest shutter speed recommended for day-to-night time-lapses? Can someone place explain this in layman terms.
(3) Exposure Target: The description of this parameter on the first page of this thread says "Where to place the highlights with respect to overexposure." I'm not really sure what that means. For example, I have highlights that are overexposed, such as the sun. My "Exposure Target" is set to -1EV. Now what? Where is the highlight "placed" with respect to overexposure? Where does increasing or decreasing the EV place the highlights with respect to overexposure? What EV is recommended for day-to-night time-lapses?
(4) Highlight Ignore: From my understanding, this parameter is used to ignore a highlight in your frame, right? So if I'm taking a picture of the sun, "Highlight Ignore" will ignore the sun? Can someone please explain this and how it can be used for day-to-night time-lapses.
My brain is fried from reading all day and trying to understand all this before asking. So that's all the questions I have for today. Any help would be great. Thanks.
It's important to first have a good understanding of what ETTR is, what it's benefits are, how it works. It's probably a good idea to read some stuff about histograms also, so you understand what a histogram represents.
1. You're understanding is correct. In live view modes, it always has data to analyse, when shooting through the viewfinder, it only has the data from the last image taken.
2. Shutter is motion control, pure and simple. Since it also controls exposure, ideally you probably want the shutter to remain open for as long as possible, subject to motion. ISO is post exposure gain. It's a little hard to explain without technobabble, but suffice to say, ISO is not an exposure control! ML knows this, so it will open the shutter for longer periods, subject to the slowest shutter setting, before increasing ISO.
3. Exposure target is where to place the highlights. It's probably best set at 0.5 EV, for maximum ETTR, until you have a good understanding of the theory, and the operation of AutoETTR.
4. I think of highlight ignore as an specular highlight control. The value set here describes the percentage of pixels in the entire image, allowed to be overexposed (or more correctly, above the limits set via AutoETTR). So for instance, if you're shooting a scene with a specular reflection, this control allows you to compensate for that reflection, so that AutoETTR will ignore it, and ETTR the important areas of the scene. Since this is based on a percentage, it's value depends highly on the scene being shot.
Thanks milligan for responding to my PM. Audionut, thank you for responding to my questions and trying to dumb it down so that I could understand, although I am still confused. Please bear with my ignorance, I'm really trying my best to understand the camera's sensor, the ML modules, and how to use these modules to create a sunset/sunrise holy grail timelapse.
To answer milligan's PM question, yes I read the thread: http://www.magiclantern.fm/forum/index.php?topic=5705.0. I also read this thread: http://www.magiclantern.fm/forum/index.php?topic=5693.0, as well as a number of other threads about ETTR. But after reading these threads, I was even more confused. I think it's because of my lack of understanding of how the camera's sensor works and the technical details of photography. I really want to learn and strive to be an expert in timelapse photography, so please help me achieve this goal.
Just to give you an idea of how I shoot my regular timelapses (i.e., not sunset/sunrise timelapses). First, I set my ISO to 100 for daytime timelapses. Then I set my shutter speed to what I believe will give me the right amount of motion blur so that the final timelapse is not too choppy or have a staccato effect. I take a test picture and see how much motion blur is in the picture. If I'm happy with the amount of motion blur, I set the ML intervalometer to a certain interval based on how fast the subject(s) are moving in the frame. For fast moving clouds, cars, or people, I typically set the intervalometer to 2-3 seconds. For slower moving subjects, I set the intervalometer to 4-6 seconds. The outcome of my timelapse is typically a smooth clip, with little to no staccato effect.
Now I'm trying to learn how to shoot sunset/sunrise timelapses; the holy grail of all timelapses. I have some options to achieve this. I can follow Gunther's instructions from LRTimelapse by manually increasing my ISO or decreasing my shutter speed (for sunset) when the light meter shows that the picture is underexposed. Conversely, I can decrease the ISO or increase the shutter speed (for sunrise) when the light meter shows that the picture is becoming overexposed. I can do this manually via the buttons on the camera, which is not preferable since it might cause camera shake; or I can do this wirelessly through DSLRDashboard. Post-processing for deflickering and stitching the pictures together would be done through LRTimelapse. By this method, it requires that I buy the full version of LRTimelapse and a wireless router for my camera. I'm trying to avoid increasing my expenses for this hobby. As an aside, is my method of creating regular timelapses the correct way or the incorrect way?
Also, someone told me about the 180 degree rule, where the shutter speed is half the interval time. So for example, if I set my interval to 2 seconds for fast moving clouds, that means (based on this 180 degree method) I have to set my shutter speed to 1 second. Wouldn't this cause too much motion blur? And wouldn't this cause a lot of information to be lost between each frame? Some clarification on this would be awesome.
The second option for me is to use Magic Lantern (ML), and I prefer this option because (apparently) all of the above can be done using the AutoETTR, deflicker, XMP, ramping, etc., modules from ML, not to mention I don't need to spend additional money on software and gadgets to make a holy grail timelapse. I want to start my studies on holy grail timelapses by learning AutoETTR. So, the following is my understanding of AutoETTR and its parameter after reading the threads suggested by others.
Trigger Mode:
I know that I need to set my "Trigger Mode" to "Always on" for timelapses. From my understanding, this allows the camera to analyze what's happening in the frame and to automatically adjust the ISO and shutter speed accordingly to compensate the light during a sunset or sunrise. When I enable Live-View, I see the RAW histogram and what is being overexposed. The RAW histogram has an "E" number and three color-coded circles (i.e., R, G, B circles with numbers inside of them).
Here are my questions for "Trigger Mode" and the "RAW Histogram":
1) Do I need to take test shots in Live-View so that AutoETTR works correctly? I read somewhere that I have to take 2-3 test shots so that AutoETTR can perform it's analysis.
2) What does the "E" number mean on the RAW histogram?
3) Is there anything I need to adjust or re-adjust after seeing the "E" number? If so, what parameters do I need to adjust or re-adjust?
4) I know that the R, G, B circles are the red, green, and blue channels, respectively. But what does the number inside the circles mean?
5) Is there anything I need to adjust or re-adjust after seeing the number inside the R, G, B, circles? If so, what parameters do I need to adjust or re-adjust?
Slowest Shutter:
I understand that during a sunset or sunrise timelapse, AutoETTR will change the ISO and shutter speed to compensate for the transition. In order to ensure that AutoETTR works correctly, I have to set the "Slowest Shutter" to be 2-3 seconds shorter than the interval time.
Here are my questions for "Slowest Shutter":
1) When the sun is setting, the interval should be fast, maybe around 3-5 seconds? The interval needs to be longer as it becomes darker, maybe 10 seconds during twilight, and maybe 15-30 seconds to properly expose the stars? In this respect, is there a way to automatically increase the length of the interval?
2) Also, I assume that the "Slowest Shutter" in AutoETTR would also need to be adjusted, or else AutoETTR won't work. Is there a way to automatically adjust the "Slowest Shutter"?
Highlight Ignore:
I think this parameter ignores the amount of highlight that is being clipped in the frame. So, for example, "Highlight Ignore" can be set to a certain percentage to ignore the clipping that occurs in a sunrise or sunset timelapse.
Here are my questions for "Highlight Ignore":
1) "Highlight Ignore" is sent based on percentage. In sunset timelapses, how do I know how many percentage, or the approximate percentage, to set "Highlight Ignore" so that AutoETTR ignores the clipping in the sun without making everything else dark?
2) Do I adjust the percentage of "Highlight Ignore" based on the RAW historgram? If so, what do I look at in the RAW histogram to know how many percentage to set "Highlight Ignore"?
That's all the questions I have for now. I apologize if I sound stupid or simply clueless, but I am so determined to learn how to shoot sunset/sunrise timelapses that not knowing how to is driving me nuts. I hope someone can answer my questions as if they were explaining it to a 10 year old. Once I have a good grip on how to shoot a holy grail timelapse using ML, I promise to create a thread that explains everything in the simplest terms possible.
Thank you everyone for your patience.
1) Technically no, but the first few frames of your timelapse may jump around in exposure until it settles. If you take a few frames first or simply set the exposure correctly then you can avoid this, hence the suggestion
2) it's the ETTR hint, it tells you how many EVs you need to move the exposure to get a "correct" ETTR exposure. This is the same as AETTR's calculation. When AETTR is 'always on' it will adjust exposure by this much for the next shot.
3) see #2
4) the higher the number the more overexposed pixels there are on that channel.
5) it means you have clipped some channels (overexposed) so you might want to reduce the exposure
Slowest shutter:
One thing that's very hard to do with this type of timelapse is keeping relatively normal or constant shutter angle. You just pretty much have to accept this and keep the interval time constant, say around 30s (there may be some more advanced ways to get around this, but I strong advise you to keep it simple for now to get the hang of it). At the beginning when the sun is still out, this means you're going to have a very tiny shutter angle which theoretically makes for very bad motion blur, but in practice it's really not so bad, esp if you're careful about choosing your subject (for example, landscapes don't have very much motion, so it's not really a big deal). Basically you just can't have your cake and eat it too.
You don't set highlight ignore based on the histogram, you set it based on your scene. For example you can't possibly hope to not clip the sun. It's a 'specular' highlight and you want to ignore it. So a certain number of pixels taken up by the sun (if it's in the frame) need to be ignored. In general the default is pretty good. If you have some type of scene with lots of specular highlights (perhaps a city scene with lots and lots of bright street lights that are 'specular'), you may have to bump up the highlight ignore percent, otherwise just leave it alone.
Milligan, thank you SO much. That made some sense to me. Wow, that felt good to learn a little more and have some questions answered.
I'm going to read your reply a few more times, and then go back and read those threads again to see if they make more sense to me now.
Do you mind teaching me more after I re-read everything?
Thanks again for the help, it's really appreciated.
dmilligan: I just got home and re-read your reply a few times to make sure I really understand what you're saying.
So the "E" displayed on the RAW histogram in Live-View is a "hint" that basically suggests how much EV I need to add to get a "correct" ETTR exposure. Is this what you were saying in #2 and #3 of your reply? Also, I think you were saying that ML's Auto-ETTR will automatically apply that "E" amount displayed on the RAW histogram to the next shot in order to get the "correct" ETTR exposure, right?
Regarding #4 and #5 of your reply, the number in the circles represents the number of overexposed pixels of a particular channel, right? You also said that I would need to reduce the exposure to make sure that these pixels are not clipped. But doesn't AutoETTR do this for me, since it automatically changes the ISO and shutter speed based on the amount of light that is changing in the scene?
About shooting timelapses. You said that the interval length that I initially set for a timelapse has to be constant throughout the duration of taking the timelapse, right? Can you elaborate on this a little more? When I first started out shooting timelapses, I read somewhere that a long interval will result in information being lost between each frame, causing a staccato effect. For example, if there are fast moving clouds in a sunset timelapse, setting the interval to 30 seconds will cause a staccato effect in the clouds.
For "Highlight Ignore," there is no way we can not clip the sun, since doing so will make everything else dark. I live in NYC and plan on shooting regular and sunset timelapses. There are tons of street lights and other bright lights in NYC. I think these are "specular" highlights right? In order to make sure that these "specular" highlights are ignored, I need to increase the percentage, or else Auto-ETTR will try to expose these "specular" highlights, which will cause the rest of the scene to be dark.
My goal is to make a timelapse similar to this guy (https://vimeo.com/98262776) using only ML. But I have some questions about his settings. He said he started with a 1/8000 second exposure? I'm not really sure what he means by a 1/8000 second exposure. Is he talking about his shutter speed, interval length, or something else? And how did he get the clouds to be so smooth if the length of his interval is long. Like you said, the interval should be constant, so he must have set a long interval at the beginning of his timelapse in order to capture the stars at night.
Thanks again, dmilligan. I'll be doing more research and then probably try out what I learned this coming weekend.
Quote from: tetsusaiga on September 01, 2014, 05:41:32 AM
So the "E" displayed on the RAW histogram...
Correct
Quote from: tetsusaiga on September 01, 2014, 05:41:32 AM
Regarding #4 and #5 of your reply, the number in the circles represents the number of overexposed pixels of a particular channel, right?
I don't think it's the number of pixels exactly, but it's proportional to the number of pixels (maybe it's percent? IDK).
Quote from: tetsusaiga on September 01, 2014, 05:41:32 AM
You also said that I would need to reduce the exposure to make sure that these pixels are not clipped. But doesn't AutoETTR do this for me, since it automatically changes the ISO and shutter speed based on the amount of light that is changing in the scene?
Right, so if AETTR is on, then you shouldn't even see this happen b/c AETTR would adjust the exposure down for you. If AETTR is off, and you're 'ETTRing' manually, then this is what you would do.
Quote from: tetsusaiga on September 01, 2014, 05:41:32 AM
About shooting timelapses. You said that the interval length that I initially set for a timelapse has to be constant throughout the duration of taking the timelapse, right? Can you elaborate on this a little more?
Not really, it has to be constant. I don't know what more I can say about that. It's just the way you have to do it (or at least it's the way you SHOULD do it for now, b/c it's simpler).
Quote from: tetsusaiga on September 01, 2014, 05:41:32 AM
When I first started out shooting timelapses, I read somewhere that a long interval will result in information being lost between each frame, causing a staccato effect. For example, if there are fast moving clouds in a sunset timelapse, setting the interval to 30 seconds will cause a staccato effect in the clouds.
In theory yes, these type of settings would look "bad". But in practice it's really not so bad, and: *you don't have any choice*
The only way I can really think of overcoming this limitation would be some kind of automated, very strong, variable ND filter. That's way too much complication. Just deal with the 'staccato' it really doesn't look as bad as you think: https://www.youtube.com/watch?v=qyAL2_TrzDI
Quote from: tetsusaiga on September 01, 2014, 05:41:32 AM
There are tons of street lights and other bright lights in NYC. I think these are "specular" highlights right? In order to make sure that these "specular" highlights are ignored, I need to increase the percentage, or else Auto-ETTR will try to expose these "specular" highlights, which will cause the rest of the scene to be dark.
Correct
Quote from: tetsusaiga on September 01, 2014, 05:41:32 AM
My goal is to make a timelapse similar to this guy (https://vimeo.com/98262776) using only ML. But I have some questions about his settings. He said he started with a 1/8000 second exposure? I'm not really sure what he means by a 1/8000 second exposure. Is he talking about his shutter speed, interval length, or something else?
If you see a time and a reference to exposure you can be sure the person is talking shutter speed.
Quote from: tetsusaiga on September 01, 2014, 05:41:32 AM
And how did he get the clouds to be so smooth if the length of his interval is long.
Like I said, it's really not as bad as you'd think. Have you actually tried settings like this too see what it looks like? Clouds move very slowly, so with clouds, it's really not a noticeable difference (in my timelapse I posted above, do you see any real difference in cloud motion from day to night? I used a constant interval, so the shutter angle varies drastically from near 0 in the day to near 360 at night). Where you get bad "staccato" effect is with faster moving things like people, birds, cars, etc.
I had replied to tetsusaiga privately, but for the benefit of any newbies, I'll repost here what I wrote to him about what ETTR is, with a bit of expansion:
Basically, and to summarize: digital sensors have more noise in the shadows; therefore, in order to avoid noise, you overexpose your shots as much as possible (without clipping), so that most of your picture is in the brighter side of the histogram (the right). If you prefer the picture darker, you can always darken it later (because you are shooting RAW). That's what ETTR is.
What is AutoETTR? Well, it's a module that calculates automatically what's the highest exposure you can make in any given picture without clipping the highlights. What's considered an "acceptable" amount of clipping? That's what all those parameters and buttons are for, to tune that to your preference.
Why is AutoETTR relevant to day-to-night timelapses? Because in these, the exposure changes with time, and you don't know in advance what the right exposure will be (unless you stay all day and night with a light meter and write down the values for each hour before your shoot ;) ). So you use AutoETTR and let it expose for you.
Will this cause flicker, when AutoETTR changes ISO or shutter? Well, yes, but then you just have to deflicker later using dmilligan's script.
Hope this solves any doubts.
Quote from: dmilligan on September 01, 2014, 04:26:02 PM
I don't think it's the number of pixels exactly, but it's proportional to the number of pixels (maybe it's percent? IDK).
Quote from: Audionut on May 29, 2014, 05:41:00 PM
The colored circles in the histogram, warn of overexposure in the color channel. Small circles show a very small amount of exposure, with the circles increasing in size. When at least 1 % of the pixels of a channel are overexposed, the numbers inside these colored circles, describe the percentage of pixels that have been overexposed in that color channel.
Also, rather then PM'ing a bunch of different people, it would be highly preferable to simply ask questions in this thread. This solves a number of problems, firstly, you don't duplicate the time from numerous members, and the answers are available in public for everyone to benefit.
Hi Everybody.
I shoot videos with Mark III MLV RAW, and I will use AETTR.
My worst case scenery is the next: in the street, I ignore specular lights from the street moving the camera out from light spot. I put the T (F) 1.5 (the widest in my lens) I press SET and I get and ISO 6400 and 31/1. I read in other post about don't get panic with that high ISO in Mark III by A1ex.
Do you recommend shot in that ISO or put a maximum of 3200 - downloading the recommended by ETTR - and overexposed in post?
As you know over ISO 1600 the differences it's huge.
Thanks.
Higher ISOs have less noise (per photo-electron). Shooting ISO6400 (which I understand is actually analog on the 5D3, on others it's digital so this advice would be different) is going to be less noisy than shooting ISO3200 or ISO1600 and bumping up to the same level in post.
If you can't get more light to the sensor somehow (wider aperture, slower shutter, add light source to the scene), then it's always going to be best to use the highest (analog) ISO as necessary. In fact this is the whole point of ETTR.
Sorry about PM-ing a number of people to get help, but I was really eager to find out some answers to my questions. I figured that some my not see my post, but will see my PM. I'll post in the thread from now on. Sorry for the trouble.
dmilligan: Thanks for confirming and answering my questions. I watched your timelapses and they all look really good. So I'm guessing in each of the day-to-night timelapses you had a constant interval throughout the whole time? What was your interval and shutter speed for the Fall Creek timelapse? I'm going to try my best to find some time tomorrow and try out a long interval time and shutter speed to see how the timelapse comes out. Do you have a recommendation for setting the shutter speed and interval for slow, medium, and fast moving clouds? If not, I can wing it and see how the timelapse comes out.
PaulJBis: Thanks for answering my questions. While we were talking about staccato, I was shocked that you said your interval was anywhere from 15 seconds to 30 seconds throughout a single timelapse. The reason I was shocked is because I kind of pieced a lot of information from my research and it said to use faster intervals for medium to fast moving subjects. For instance, this timelapse tutorial (https://www.youtube.com/watch?v=W4SzZXLiyvk) at 3:41 to 4:45 makes the distinction between smooth and jerky timelapses. He states, essentially, that fast moving subjects require a shorter interval to obtain a smooth timelapse, while a longer interval will result in a more jerky/choppy timelapse. This is what I was talking about in my cloud example in our PM and, having made smooth timelapses in this way, I was shocked to hear that a smooth timelapse can also be achieved through a long interval. I'm going to shoot a timelapse, any suggestions for slow, medium, and fast moving clouds?
By the way, I'm currently using the trial version of LRTimelapse to make my regular timelapses. Do you guys suggest buying the full version of LRTimelapse? I was thinking of purchasing it because I'm capped at 400 frames and I'm not sure that's enough for a day-to-night timelapse. On the flip side, do you guys suggest I subscribe to Adobe CC instead?
Thanks again for everyone's help and patience.
Quote from: tetsusaiga on September 03, 2014, 05:28:52 AM
PaulJBis: Thanks for answering my questions. While we were talking about staccato, I was shocked that you said your interval was anywhere from 15 seconds to 30 seconds throughout a single timelapse.
No, that's not what I said. I said that I normally use intervals of 30 sec. or 1 min., but what I do NOT do is to change interval times within a single timelapse. If I start with a 30 sec. interval, I stick to it until the end.
Edit: or, in other words, what dmilligan said.
Quote from: tetsusaiga on September 03, 2014, 05:28:52 AM
What was your interval and shutter speed for the Fall Creek timelapse?
details in this post: http://www.magiclantern.fm/forum/index.php?topic=12330.0
(I'm pretty sure the shutter speed varied from 1/8000 all the way to 32", so the entire range of what the camera is capable of)
Quote from: tetsusaiga on September 03, 2014, 05:28:52 AM
Do you have a recommendation for setting the shutter speed and interval for slow, medium, and fast moving clouds?
I wouldn't really say clouds move slow, medium or fast, I would say they move slow, very slow, or very very slow. That's why I would say you will almost never have an issue with this, clouds just move too slowly for it to matter.
You seem to me to be overly concerned with setting your interval to get "good/smooth motion". For me, I consider this a secondary goal that is subservient to other more important things. For example, it's called a time-
lapse for a reason, time is lapsing. In general the more time that lapses, the more interesting the time-lapse is. I would much rather see an interesting, fast moving time-lapse that is "choppy", than a slow boring one that is "smooth".
I will always set my interval first without regard to shutter speed or motion, based on how much time I want to capture or feel that the scene calls for being captured. Then after I decide that, I can try to get "good" motion with a shutter speed that gives me reasonable shutter angle (the goal being 180, i.e. interval time = 2 * shutter speed). Maybe I can achieve that by adjusting aperture or using an ND filter. But if I can't then I just let it be. My interval that I select does not serve the purpose of "good motion", instead the shutter speed serves the interval I've chosen and "good motion". And if I can't get the shutter speed there, well then I don't worry about it.
In general I never use any interval time less than around 15 to 30s when timelapsing nature or landscapes (any slower and I just feel the result is too boring). The only thing that might call for a shorter interval is something that changes more rapidly, such as people moving about, cars, boats, vehicles, building or assembling things (like a guy building a lego set, etc.), or perhaps a fast moving storm.
It helps to have a good strong ND filter.
Of course all of this is just my subjective opinion, so take what you will and disregard the rest.
PaulJBis: Sorry, I should have phrased what I said a little differently. What I meant to say is that I was shocked your interval was either 15 seconds OR 30 seconds for a single timelapse. That was my mistake for phrasing it incorrectly. But I now understand that a single timelapse can have a long interval, as opposed to my initial misconception of setting a short interval to make sure I capture enough information. Thanks for clearing that up for me.
dmilligan: You're right that clouds do move slow, very slow, or very very slow :D . To answer your implied question, yes, I am overly concerned with getting "smooth" timelapses. I think my concern stems from the tutorial (https://www.youtube.com/watch?v=W4SzZXLiyvk (https://www.youtube.com/watch?v=W4SzZXLiyvk)) at 3:40 to 4:30. Maybe I interpreted this section of the tutorial incorrectly, or applied it to the wrong scenarios.
Your approach to what you set first in your timelapse is opposite of mine, which I now know is the incorrect way. I'll try to analyze what I'm shooting and then set my interval first, followed by the shutter speed and ISO. I like taking timelapses of nature or landscape, so I'll remember to set my interval anywhere between 15 seconds to 30 seconds. I'm going to be camping in Pennsylvania, upstate New York, Lake George, or Delaware next month, so I kind of want to have this down before I go.
With respect to the 180 rule, I just want to make I sure understand it. For example, if my interval is set to 30 seconds, I should divide the interval by 2 to get my approximate shutter speed, right? In this example, an approximate shutter speed of 15 seconds. But this 180 rule shouldn't matter anymore once I learn how to use AutoETTR, right?, since AutoETTR automatically adjusts the shutter speed and ISO based on the available light in the scene.
My last question for the day is about your comment on the shutter speed varying from 1/8000 all the way to 32 seconds. I'm assuming that it was AutoETTR that varied your shutter speed, right?
Since everything I pieced together in the past year about timelapse has essentially went out the window, I'm going to try and shoot a regular daytime timelapse with everyone's' comments in mind. Hopefully the final product will come out to what I expect. I eventually want to learn how to shoot sunset/sunrise timelapses, and hopefully I will soon. Dmilligan, your timelapse link above is really nice, especially at the 30 second mark where the cloud appears out of now where and moves across the sky.
I hope that you guys can continue to educate me and correct me where I'm wrong, like you did above. Thanks again and it's really appreciated.
Write short, please. Too much emotional thinkings. Thanks.
There's no better way to learn, then getting out into the field and trying things.
I would suggest you take the knowledge you currently have, and try some some practice.
Sorry for the long posts, but I didn't know how to explain things without going into the nitty-gritty details. I'll do my best not to make it long.
I just went outside to my backyard to try and shoot a timelpase while the sun was setting. I wasn't sure if AutoETTR was working because the exposure wasn't automatically changing as the sun was setting. In other words, the sky was getting darker, and so was the pictures. It didn't seem like AutoEttr was exposing to the right. Here are my settings:
1) AutoETTR with the following parameters:
- Trigger Mode = Always On;
- Slowest Shutter = 16 second;
- Exposure Target = -0.5EV;
- Highlight Ignore = 0.1%;
- Midtone SNR Limit = 6EV;
- Shadow SNR Limit = 2EV; and
- Link to Dual ISO = On;
2) Post Deflicker with the following parameters:
- Sidecar File Type = UFRaw;
- Deflicker Percentile = 50%; and
- Deflicker Target Level = -4RV;
3) Intervalometer with the following parameters:
-Take a Pic Every = 20 seconds;
- Start After = 3 seconds;
- Stop After - Disabled; and
- Manual Focus Ramp = Off.
With these settings, I took a few test shots and was able to see what was being overexposed via the zebras in Live-View. After the test shots, I enabled the intervalometer and let the camera do its thing. I stood next to it the entire time and was checking the image preview and Live-View after each shot. As the sun was setting and the sky getting darker, the ISO and shutter speed didn't change at all. Then my battery died, which meant that it was game over for the night. What did I do wrong?
I would recommend not using LV for timelapse (probably why your battery died). Also did you have the quality set to raw? Did you hear the beeps from AETTR? Did you see the expo messages from AETTR? Did you see any errors, specifically "Raw Error"? Did you see the other raw overlays during QR, like the histogram(assuming you had them enabled)? Finally, what camera are you using (there have been reports of issues with AETTR not working correctly on certain cameras that aren't as well maintained)?
dmilligan: I think I can answer only some of your questions.
1) I thought I need to use LV to use AutoETTR? Guess not, after your comment. Not sure why I thought I had to us LV, but I will try again tomorrow without using LV.
2) The Canon and ML setting is set on RAW.
3) I didn't hear any beeps from AutoETTR at all. Didn't know I had to hear beeps actually. What do the beeps mean? And what do I need to do to hear the beeps?
4) I didn't see the expo messages from AutoETTR. What are the expo messages supposed to say? And what do I need to do to see the expo messages?
5) I did not see any errors or "Raw Errors."
6) I have the zebra and Raw Histogram enabled under the Overlay tab in ML. I only see zebras and the Raw Histogram.
7) I'm using a Canon 600D (T3i). I might have the wrong ML/TL nightly build installed on my camera. A while back, I installed TL [600D]NewMem.zip, which probably doesn't have a properly working AutoETTR. Which ML or nightly build should I be using on my camera?
Thanks again for the help.
Update: I just downloaded the most recent ML nightly build and it makes the beeping sounds and shows the messages you were talking about. I'll give it another try tomorrow after work and hopefully I'll be successful this time.
Sorry guys, but I was given a big project at work and didn't have time to test out the AutoETTR and other ML features in a timelapse. I'll get right on it when things at work die down a little.
Hi guys. I was able to find some time last night to shoot a day to night (sort of) sequence. Right off the bat, there's a lot of flicker, although it seems that AutoETTR has been working well after I downloaded the latest Magic Lantern Nightly Build. Here is the link to the timelapse: https://www.youtube.com/watch?v=NCNcF8tdY1g&feature=youtu.be. Below are my settings for this sequence:
1) Modules:
- raw_rec = On;
- deflick.mo = On;
- dual_iso.mo = On; and
- ettr_mo = On.
2) AutoETTR with the following parameters:
- Trigger Mode = Always On;
- Slowest Shutter = 32 seconds;
- Exposure Target = -0.5EV;
- Highlight Ignore = 0.1%;
- Midtone SNR Limit = 6EV;
- Shadow SNR Limit = 2EV; and
- Link to Dual ISO = On.
3) Post Deflicker with the following parameters:
- Sidecar File Type = UFRaw;
- Deflicker Percentile = 50%; and
- Deflicker Target Level = -4EV.
3) Intervalometer with the following parameters:
-Take a Pic Every = 35 seconds;
- Start After = 3 seconds;
- Stop After - Disabled; and
- Manual Focus Ramp = Off.
Although I enabled post-deflicker, I didn't use the sidecar file in this timelapse. I think this is a little too advance for me right not. I'll revisit post-deflicker when I get the basics down first.
So, I followed LRTimelpase (Gunther's) holy-grail tutorial but, as you can see, there's a bunch of flicker in the timelapse. Also, I'm not sure what that blip was around the 2 to 3 second mark of the timelapse. Is there something wrong with my settings? Any help to remedy this issue would be great.
If you don't use the deflicker sidecars, you're going to have lots of flicker. The whole point of the sidecars is to remove the flicker we're expecting to get.
If you're using Lightroom, then you need to use XMP sidecars not UFRaw. If you use the XMP sidecars, you should pretty much automatically end up with a deflickered sequence when you load it into LR.
The sidecars simply contain a correction/adjustment to the exposure, all you need to do to deflicker is to apply this correction. LR (ACR) automatically applies develop settings stored in XMP sidecars. You'll notice that the exposure slider has been moved around in all your images. All LRTimelapse does is create these sidecars with exposure corrections that it computes, so the workflow is basically identical, except the sidecars are created in camera by ML and you don't have to run a third party tool (you also don't have to pay for said tool).
Also, if you have Adobe Bridge, you can use my script that does basically the same thing (generates XMP sidecars with exposure corrections):
http://www.magiclantern.fm/forum/index.php?topic=8850.0
dmilligan: Thanks for the input. I'm going to switch the deflicker to XMP. So let me get this straight, I basically import the Raw files from my SD card and LR will automatically deflicker the Raw files using the XMP files? I'm going to give this a try in a few days. Thanks again.
Can some teeach me how to synchronize the XMP files with my raw files? I think I need to save the raw and XMP files onto my hard drive and then import the raw files into LR5. does the XMP files automatically get applied to the raw files upon import into LR5 from my hard drive?
Yes it should
thanks, I'll give it a try when the weather gets better here.
I have time over the weekend to try and shoot a sunset-holygrail timelapse.
This time I'll be enabling the deflicker module with sidecar XMP file.
But I have a questions about the XMP files created by the ML deflicker module.
So I basically save the CR2 file and ML XMP files onto my hard-drive.
Then I import both the CR2 files and XMP files into Lightroom.
I'm assuming this will change the exposure to reduce any flicker, right?
After this, I would be using LRTimelapse to create the timelapse video.
In this instance, can I actually use the deflicker program in LRTimelapse to do additional deflicker-ing? Or will this not work?
Thanks.
I'm trying to shoot a holygrail timelapse right now. When I take a test shot, the next picture comes out extremely under exposed. So I increase the highlight ignore to 3 and everything looks fine. But now it's getting dark out and the pictures are too bright - I.e., the pictures are way brighter than it really is outside. Did I do something wrong?
Quote from: tetsusaiga on October 04, 2014, 12:38:23 AM
I'm trying to shoot a holygrail timelapse right now. When I take a test shot, the next picture comes out extremely under exposed. So I increase the highlight ignore to 3 and everything looks fine.
Post a CR2. You probably don't want highlight ignore set to 3, unless you have a large amount of specular highlights.
Quote from: tetsusaiga on October 04, 2014, 12:38:23 AM
But now it's getting dark out and the pictures are too bright - I.e., the pictures are way brighter than it really is outside. Did I do something wrong?
If there is no overexposure, then you probably got the correct ETTR results. If you still have highlight ignore set to 3, you probably want to revisit that setting.
Audionut, thanks for replying. I'm still out trying to shoot the timelapse. I'm going to try and process the sequence through LR5 and LRTimelpase and see how the end result is like. I'll post a CR2 file after.
As an aside, the reason why I set highlight ignore to "3" is because the sun was in my frame, and I think ML was trying not to overexpose the sun, which made everything else really dark.
Yes, you will need to do that for the sun (never mind the cr2). I'm not sure how the guys transition from sun in frame to darkness with autoETTR.
I've bugged dmilligan previously about having highlight ignore as a rampable feature in his module.
use a wide enough angle lens and the sun is small enough it doesn't matter :P
dmilligan: LOL...thanks for that, I'm actually working on getting my hands on a wide angle lens; I need to save up some money first though. The 24-70 standard lens on my crop sensor is not capturing enough of what I want in the frame.
I just got home from the beach and I want to process the timelapse, but I ran into a problem already.
I used the deflicker and AutoETTR modules in ML, which gave me a bunch of XMP and CR2 files.
I imported the pictures into LR5 and the exposure of each picture is different, so I'm assuming the XMP files that ML created for deflickering works. But I'm stuck from this point on.
If I use LRTimelapse, the first thing I need to is "initialize." But if I do this, the exposure for each picture is set to zero, which means all the XMP deflickering files created by ML is useless.
Does anyone have a workflow for this?
By the way, how do I post a CR2 file so that you guys can download?
If you want to use ML's deflicking, then just export the CR2s to JPG or TIFF in Lr and compile those into a video. If you want to use LRT, it sounds like you'll have to throw out ML's derflicker and start from scratch and let LRT do the deflicking (you can always backup the XMPs from ML in case you need to use them later).
Just save up $300 http://www.amazon.com/Rokinon-FE14M-C-Ultra-Canon-Black/dp/B003VSGQPG#
Thanks to dmilligan, audionut, pauljbis, the ML team, Gunther from LRTimelapse, and everyone else that helped me with learning how to make a timelapse. I shot a sunset timelapse last night using Auto-Ettr and Deflickering modules, and it came out better than I expected (I was expecting a lot of flickering or over/under exposed timelapse). Here's my short timelapse clip (5 secs), which I'm sure can be improved, which I'm striving for: https://www.youtube.com/watch?v=QiwjuJS5Eto&feature=youtu.be
By the way, do you guys think setting my highlight ignore to 3 or 4 EV was the right move? Maybe I should have set it to 1 or 2 instead?
The highlight ignore parameter is a percentage of pixels in the frame, not an EV.
Use raw based zebras (http://www.magiclantern.fm/forum/index.php?topic=12096.0). Increase the highlight ignore value until wanted details in the scene start to overexpose. In other words, until something other then the sun is overexposed.
audionut...I have the raw histogram and zebra enabled. So are you saying I should over expose some things in my frame other than the sun? I set my highlight ignore to 3 or 4 because the default settings made the next picture really dark. I played around with highlight ignore until I was happy with the exposure of the next picture. Is this the correct way to do this? I might try again tomorrow.
The highlight ignore parameter says, ignore this percentage of pixels in the image.
The sun takes up some percentage of pixels in the image.
Using raw based zebras, you can adjust the highlight ignore setting so that the sun is completely ignored (overexposed), allowing the rest of the image to be ETTR'd correctly.
If you just randomly set the highlight ignore parameter to large, you may find wanted details in the image also being overexposed (rather then only the sun).
Thanks audionut. I'm going to give it a try again in a few days.
I have a questions about Auto-ETTR. When I was shooting the timelapse, I noticed it displayed "Auto ETTR Settled at 1/(shutter speed)" after each picture. What does it mean when Auto-ETTR settled at a shutter speed?
Also, I was wondering if there is any way to ramp the interval time? For example, I want the intervalometer to take a picture every 5 seconds. As the sun is setting and less less light, I want the intervalometer to take a picture every 10 seconds.
I felt that the sunset timelapse I made the other day was moving too fast.
Quote from: tetsusaiga on October 06, 2014, 02:09:21 AM
What does it mean when Auto-ETTR settled at a shutter speed?
"Hey, I've just looked at the scene you want me to ETTR, and I reckon this is the shutter speed you need. So I am going to settle on that shutter speed. Good luck"
Quote from: tetsusaiga on October 06, 2014, 02:09:21 AM
Also, I was wondering if there is any way to ramp the interval time? For example, I want the intervalometer to take a picture every 5 seconds. As the sun is setting and less less light, I want the intervalometer to take a picture every 10 seconds.
You should be able to do that with dmilligan' Advanced Intervalometer (http://www.magiclantern.fm/forum/index.php?topic=8431.0).
Audionut, thanks for replying. By the way, thanks dmilligan for creating adv_int.mo.
I read dmilligan's entire thread about adv_int.mo and I'm not really sure how to use this module. I'm not really sure what keyframes are and I'm not sure why it's set based on time.
From what I read, I think keyframes tell ML when to change certain exposure settings (e.g., ISO, shutter speed, and aperture) when the clock on the DSLR reaches that set time. But doesn't this require you to predict the time of when the sun is setting/rising?
Also, why does dimilligan's example of adv_int.mo change the aperture? Wouldn't this make something that is in focus, out of focus after the ramping?
Can someone explain to me in very simple terms how Auto-ETTR works alongside adv_int.mo, using the specific example of a sunset timelapse.
What I intend to use adv_int.mo for is to somewhat slow down the daytime portion of my sunset timelapse to kind of match the speed of the night-time portion of the timelapse. In my recent test with Auto-ETTR (https://www.youtube.com/watch?v=QiwjuJS5Eto&feature=youtu.be), the daytime portion was too fast for my liking, so I wanted to find a way to slow it down - i.e., taking more pictures during the day. My interval for my sunset timelapse was set to 30 seconds, so I wanted to slow it down by maybe setting the interval to 10 seconds.
I going to continue practicing with Auto-ETTR, deflicker, and dual_ISO, but I would love to move on to using adv_int.mo also.
Quote from: tetsusaiga on October 06, 2014, 09:23:05 PM
I'm not really sure what keyframes are and I'm not sure why it's set based on time.
http://en.wikipedia.org/wiki/Key_frame
Quote from: tetsusaiga on October 06, 2014, 09:23:05 PM
From what I read, I think keyframes tell ML when to change certain exposure settings when the clock on the DSLR reaches that set time.
Yes, in "global time" mode. In the other mode, it simply counts frames, so the keyframe "time" is just the frame number.
Quote from: tetsusaiga on October 06, 2014, 09:23:05 PM
But doesn't this require you to predict the time of when the sun is setting/rising?
I'm pretty sure that cavemen could do this, or at least the dudes who built Stonehenge...
http://aa.usno.navy.mil/data/docs/RS_OneYear.php
Quote from: tetsusaiga on October 06, 2014, 09:23:05 PM
Also, why does dimilligan's example of adv_int.mo change the aperture? Wouldn't this make something that is in focus, out of focus after the ramping?
It could, and that might be the point. Or, your subject may also easily fit in the smaller DOF of the larger aperture, in which case it wouldn't make any difference. For example: landscapes are typically hyperfocal at infinity even at large apertures, so when there's plenty of light we want to use a smaller aperture for sharper photos, most lenses perform best around f/8, and then when light is low, we sacrifice the extra sharpness for the extra light we get from having the lens wide open (~ f/1.8 or whatever).
Quote from: tetsusaiga on October 06, 2014, 09:23:05 PM
Can someone explain to me in very simple terms how Auto-ETTR works alongside adv_int.mo, using the specific example of a sunset timelapse.
I think of it like this:
AETTR sets the proper exposure, using shutter speed and ISO (or only ISO), automatically. adv_int sets more aesthetic or artistic properties such as aperture, focus, and interval time, that the photographer wants manual control over, based on his knowledge.
tetsusaiga, try this:
http://photoephemeris.com/
Thanks again to everyone for helping me out. I would never have thought I could make a partial sunset timelapse until you guys helped me. Once I get paid, I'm going to setup a PayPal account and make a donation.
I wish Canon would learn from you guys, instead of taking stupid (well, not so stupid since we still buy their products) marketing strategies to monetize from their devoted consumers. Just give us what we want, Canon!
As for increasing or decreasing the interval time, I see that the sun sets around 5 at where I live. I want to have an interval of about 5-10 seconds while the sun is out. But I want to increase the interval time to 15-25 seconds as the sun is setting, and 25-40 when the sun is basically completely set.
How can I predict when to set these keyframes and how do I do that?
Also, it's my understanding that, if I use ML deflicker, I need to compensate 3-5 seconds for the deflicker module to do its thing, in addition to the 2-3 seconds for the camera buffer to clear. That's a total of about 8 seconds just to do in-camera processing. Is this true?
Thanks again for everything. Once I get a hold of these modules, I want to contribute to the community by writing a thread for newbs like me.
Is possible to use auto ettr with bulb timer for day to night timelapses?
Yes you can create a picture style that has a lower curve so it looks under exposed compared to the normal picture styles.
Hello, I've been trying to use ETTR for the 1st time, I have a 6d, but I think I'm using wrong, coz I don't see any difference, and the histogram isn't changing much (to the right as I see in some photos ), and the highlight ignore isn't making any difference as well, I tried at 30% and 0.1%.
Any help or tips would be great. Thanks
Test setup for highlight ignore:
Put a white paper on a black cloth/paper and change highlight ignore percentage. At higher ignore levels ETTR will change exposure and overexpose your paper.
Ok so I did the test, and with higher highlights ignore value ETTR changed the Shutter speed from 1/40 to 10" and it did overexposed the paper as u said.
But I thought that this setting is so it doesn't over expose the highlights, to help with astro shots and light polution, no?
If you don't want to have any highlight overexposed you should use 0%.
Settings >0% are for landscape (for example) where the sun is in the frame. It would not make that much sense to have the sun exposed correctly. And for highlights in architecture where sun is reflected in small areas.
Oh ok I got it all wrong :/ thanks again for the help. So basically ettr module is just an auto mode to set the exposure time and iso for ur shot, did I get it right now?
Yes, that's all about.
May I ask where you got it wrong?
I thought it pushes ur graph to the right without long exposure. And the highlights ignore though that it blocks highlights from over exposing even at long exposure, that's why I talked about the night light pollution earlier.
Hello,
Is there a way to change the default lower ISO from say 100 to 160? I'm using a Canon 7D and I would like to have it be 160 ISO.
Thanks
Why would you want to do that? I can't think of any valid reasons. 160 is a digital ISO anyway.
"Why would you want to do that? I can't think of any valid reasons. 160 is a digital ISO anyway."
http://shootintheshot.joshsilfen.com/2010/05/13/canon-hd-dslr-native-iso/
http://www.magiclantern.fm/forum/index.php?topic=10111.0
Quote from: Audionut on March 18, 2015, 11:15:37 PM
http://www.magiclantern.fm/forum/index.php?topic=10111.0
Thanks for the info.
Thanks!
I'm trying to make a little test. I'm in low light ambient. If I press "set" for the ETTR there is a bip and than a message on the screen of my 7D that say "Expo limit reached".
When there is this message it means that the technique will not work?
thx
Access Auto-ETTR submenu and change exposure time limit.
I'm wondering if my understanding of ETTR and the resulting rule-of-thumb (ROT) is more or less correct. Or flawed?
And sorry if this has been addressed before within this 170+ post thread and 4 pages. I did read several pages and didn't notice it being addressed.
To me, if the camera's base ISO (typically 100 for Canon) isn't suitable, then ETTR may not be all that useful or appropriate. It's mostly an issue at lower light levels, like dusk, dawn, night, interiors, landscapes, etc.
This could involve a moving subject demanding a relatively high shutter speed to "freeze" the action, or not enough light (even with tripod), or perhaps too much wind for tripod and long exposure. The use of Dual-ISO is also a factor, and my impression is that Dual-ISO increases the advantages of using ETTR with ISO 100.
If ISO 100 isn't appropriate for a specific capture, then you can settle for the histogram not going all that far to the Right, or increase the ISO to get the histogram to the Right.
But when you increase the ISO, noise increases and the tonality quality decreases. It gets to be a trade-off of whether ISO is the priority, or shutter speed.
I think with an ISO-less sensor like Exmor's, you'd tend to favor ISO 100 and whatever shutter speed that results in, within reason. With Canon sensors not being ISO-less, it's less clear-cut what to do when you can't use ISO 100.
Or not? I find I learn more when someone "corrects the error of my ways".
Quote from: l_d_allan on April 24, 2015, 10:21:07 PM
But when you increase the ISO, noise increases and the tonality quality decreases.
This is actually completely incorrect. You're describing noise and bit depth here, I'll tackle bit depth first because it's the shortest explanation.
http://www.cambridgeincolour.com/tutorials/bit-depth.htm
14bit cameras are capable of producing 16,384 distinct shades of grey (colors). Unfortunately, this is only when the histogram is pushed to the right and it nears overexposure So as the histogram moves further to the left, there are less bits available to encode the data. So extreme shadows may only have 4 bits (16 shades of grey) or less. Since the reduction of luminance also reduces the possible number of colors, 4 bits may be enough.
The issue arises where there is wanted detail in these extreme shadows, and post processing is used to increase the luminance. As the luminance increases, more colors are capable of being reproduced, however since the original data may have only contained 16 colors, trying to generate (for instance) 120 distinct colors from 16 colors is a lesson in frustration.
Bit depth is only a concern to the user if he decides to post process.
Noise is a little more complicated since there are various sources in digital photography. There are two main sources of noise in everyday photography, shot noise and read noise.
http://theory.uchicago.edu/~ejm/pix/20d/tests/noise/index.html
The sun, a light bulb, or any other light source emits light. This light is made up of particles called photons. These photons bounce all over the place, with things like mirrors reflecting lots of the photons, and a black hole reflecting none.
The first thing a photo/videographer should understand is that ISO
does not control exposure. Period!
Exposure is the capture of light (photons) from a scene, and this can only be controlled with shutter and aperture. Aperture determining the size of the opening though which the photons travel through the lens, and shutter controlling the length of time that the sensor is exposed to the photons. Open the aperture and you create a bigger hole for the photons to flow through. Increase the shutter time and you create a longer time period for the photons to flow.
Your exposure settings control the shot noise. Shot noise is the square root of the number of photons. So shot noise actually increases with increasing light, but luckily for us, the number of photons increases faster then the level of noise. More light is better, always! So in terms of noise, a photographer should always attempt to capture as many photons as possible, only being limited by motion (shutter) and depth of field (aperture).
ISO is used to control the sensitivity of the sensor to light (read noise).
http://www.clarkvision.com/articles/iso/index.html
Bright Dark
Total dynamic range of scene [****************************************]
ISO 100 [*************************]
ISO 200 [************************]
ISO 400 [***********************]
ISO 800 [**********************]
ISO 1600 [*********************]So ISO 100 for example may be able to capture up to 80,000 photons of light, but since it is rather noisy on Canon cameras, once the photon count drops below 40, there isn't enough light to outweigh the noise produced by the camera. Whereas ISO 1600 for example may only be able to capture up to 5,000 photons, however, it can capture photon counts as low as 4 before the noise produced by the camera is greater then the number of photons captured. These are example numbers, but I'm sure you get the point.
So one thing that should becoming clear is that higher ISOs do not increase noise. In fact, higher ISOs are less noisy. Higher ISOs can capture a smaller number of photons, before that number of photons is less then the noise produced by the camera. Higher ISOs cannot capture the same amount of photons (light) as lower ISOs, but a photographer should only be using higher ISOs when the number of photons (the amount of light) is lower then the maximum for that ISO.
Where the lines get blurred is due to the shot noise. So we have a dark scene, we crank the ISO up, but the image appears to have more noise then an image taken at ISO 100, with the same
rendered brightness. That's simply because the light itself that has been captured, contains more noise. Darker scene = less light = less photons = more (shot) noise.
It is very easy to see that higher ISOs have less noise then lower ISOs. Using ETTR principles, take a shot with the camera set to ISO 1600, then without changing any other settings, take another shot at ISO 100. In post processing increase the ISO 100 shot by 4EV and observe the results.
TLDR: Set the shutter speed to capture the motion. Use ISO as necessary to ETTR.
Hi there.
I'm quite new with timelapses and never heard of ETTR before I came across this thread.
From the little I've read, the ETTR is the solution for timelapses where the exposure is changing a lot like sunrises/sunsets.
Did I get the basic part right? I hope so.
Anyways, I tried to follow the steps in this thread and some other instructions I found online in order to get a proper exposure during my timelapses, especially during sunset ones.
So far, I got bad results. Really bad ones.
The problem I've noticed is that the ETTR is over-compensating too much. So instead of the scene to go gradually darker it gets gradually lighter which is not natural and looks quite bad.
And I'm talking about very short timelapses here, not all day long. Like 5 seconds long. (120 frames, 24fps)
So far I didn't have time to play too much with it but first I used it on the default setting and then I tried tweaking it a bit hoping for better results which failed even more.
So the first frames are good (because it's the exposure I set). The contrast is good, the colors are good. Everything is fine. As the frames are passing, the scene gets lighter, the contrast is lowered and the colors become dull.
I'd post an example but I was so frustrated with the results that I deleted all those failed attempts.
I know this is not a thread about timelapses and that there are million of instructions online but I was just wondering if someone had some suggestions for me.
I have few timelapses shot in manual mode where the light didn't change and that's fine. No special skills are need there anyways.
But when the light changed a lot I tried using manual mode which resulted in the scene getting too dark very fast. I tried aperture priority where I got the best results but I wasn't able to correct the flickering in post production even using LRTimelapse software. And with ML and ETTR I got the worst results which I already mentioned.
Any advices would be much appreciated.
Thanks.
Daniel
@Danieloncareric
Go and watch the videos on the LRTimelapse site. For example.
You need to do some post processing.
I did watch the LRTimelapse tutorials from the original creator but I still couldn't get anything useful.
And I haven't found any video where he mentions the ETTR which is my main trouble and the essence of this thread.
> TLDR: Set the shutter speed to capture the motion. Use ISO as necessary to ETTR.
Thanks for the thorough explanation. As I expected, my "rule of thumb" was less-than-informed.
BTW: This issue is being written about on the DPR web-site:
"What's that noise?"
http://www.dpreview.com/articles/8189925268/what-s-that-noise-shedding-some-light-on-the-sources-of-noise
But don't blindly use ISO with ETTR.
Up go about 1600 on a 5DII, http://www.clarkvision.com/articles/iso/
Quote from: Danieloncarevic on April 26, 2015, 02:31:42 AM
The problem I've noticed is that the ETTR is over-compensating too much. So instead of the scene to go gradually darker it gets gradually lighter which is not natural and looks quite bad.
If ETTR is overexposing (non-specular highlights are getting clipped to white), then check your SNR limits, they're probably too high. If it just looks "too bright", but nothing is overexposed, well that's the point of ETTR. You will simply turn down the exposure in post to make it "look right", the result of this will be identical to using lower exposure in camera, except with less noise. This is the whole point of ETTR.
For deflickering you can try my bridge script (http://www.magiclantern.fm/forum/index.php?topic=8850.0), or the deflick.mo module (deflicker in camera).
Hi,
I've done my first AETTR night to day timelapse yesterday with my Canon 550D and ML v2.3 with an interval of 25sec and slowest shutter at 20sec. Everything went well except a little problem. The shutter speeds written in the EXIF data into the .CR2 files seems wrong for some pictures.
As an exemple here as some exemple of 2 consecutive pictures with different luminosity even the exif file show the same shutter speed value (that's not apertuer flickering cause I used the lens twist technique and the weather didn't change between these 2 pictures).
(http://106.imagebam.com/download/qOVDWNMNWihAi1K-gMCiww/41045/410447170/Exif%20infos.jpg)
Maybe AETTR use different shutter speeds than the ones from the 550D camera (with shorter interval than 1/3 EV) and that's the ones from the camera that are written in the EXIF data but it's just a supposition.
Is there a way to have the proper value in my CR2 files except using the deflicker module? (I don't want to apply deflicker in the camera cause I should increase my interval to let it calculate deflicker. Also I'm using LRTimelapse to postprocess my timelapses and I need to keep the exposure initial value at 0 to let me change it as I want on postprod). Or maybe there is a way to let the deflicker module only create the xmp files (with the correct shutter speed value) but without applying deflicker.
These bumps in luminosity without the right shutter speed value make LRtimelapse unable to find the right HolyGrail keyframes and induce big bumps after applying the HolyGrail compensation.
Here is what it looks like after the HolyGrail compensation. (The pink curve shouldn't have these crazy bumps with right shutter speed value in the CR2 files)
(http://107.imagebam.com/download/ISp9xRIZeM9ze2fCz0XfyA/41045/410447180/LRTimelapse%20luminance.jpg)
Any suggestion to sort that out will be great.
Thanks
Yannick
25 seconds is a long time. My guess is your scene luminance changed.
AETTR is not designed to produce the same overall exposure between shots. It's designed to ETTR.
The EXIF values in the CR2 are correct. There's really no way they could be wrong. ML does not interfere with this process in any way.
I noticed that in your screenshot it says f4, yet you say you used the lens twist trick. If that was true then the camera can't communicate to the lens and there shouldn't be any aperture EXIF information (normally you get something like f00). So how did this information get there?
Thanks for the answers.
I had to use 25 sec interval in order to shot the stars for the night part of the timelapse.
If the scene have changed (for exemple with a cloud going in front of the sun), the luminosity would only have change on the ground and not in the sky. Here, that's the overall luminosity that have changed and the sun was not even out at that time.
I've well understand the purpose of ETTR to change the overall exposure between shots but when the ETTR make changes, my shutter speed should have changed in the EXIF. Here, the values are the same. There are 24 consecutive pictures with a shutter speed of 1/200 sec and there's just a big bump after the 13 first ones. The same weird bump happen after 7 of the 19 pictures at 1/100 sec.
The next exact simlar bumps only happen when the ETTR change the shutter speed to 1/100, 1/125, 1/160, 1/200 or 1/250 (I only talk here of the small part of the all sequence)
That's why I was assuming ETTR may take pictures with shutter speed different from the Canon Camera like 1/115 or 1/225 and writting the wrong value in the EXIF. I should look at the code to understand it better.
But thanks for you suggestion even I don't think the problem comes from the scene that have changed.
Dmillihan,for the f0, you're right, I've change it afterwards in LRTimelapse and added it on the capture to show the lens original value.
(how can I active auto notification on the forum? I've activated it in the options, but don't see where I can switch it on a post, it doesn't appear in the "Attachement and other options")
It is only possible to use Canon shutter speeds (however the values Canon displays aren't always rounded correctly, e.g. what Canon calls 30" is actually 32")
The reason I asked the question I did was that I assumed you must have changed the metadata yourself, and so is there a possibility you also accidentally modified the shutter metadata as well?
If you really think that metadata is truly wrong from the camera, then find a way to reproduce the issue on a static scene and upload some untouched example CR2s.
(Email notifications don't work on this forum, AFAIK it's disabled due to bandwidth constraints on the mail server, with the exception of a few threads and PMs. You can, however, use the tapatalk app to get notifications.)
Quote from: yannick_c on May 19, 2015, 01:48:57 AM
If the scene have changed (for exemple with a cloud going in front of the sun), the luminosity would only have change on the ground and not in the sky. Here, that's the overall luminosity that have changed and the sun was not even out at that time.
25 seconds is an extremely long time for photons to hit the sensor. Your eyes won't notice the exposure difference you see in the images above, because you are there and the exposure change is gradual (your eyes/brain taking constant exposures). The camera on the other hand, only sees 25 second blocks of luminance, and it doesn't capture gradual changes to scene luminance during the exposure. It simply captures the total number of photons hitting the sensor during that time period.
During sunrise/sunset, scene luminance
constantly changes. In the brighter image, more photons hit the camera sensor.
I think I have spotted the problem. It comes from the file shoot.c
Looking at the source code, the shutter speed values are rounded like that :
int expo_value_rounding_ok(int raw, int is_aperture)
{
if (is_aperture)
if (raw == lens_info.raw_aperture_min || raw == lens_info.raw_aperture_max) return 1;
int r = ABS(raw) % 8;
if (r != 0 && r != 4 && r != 3 && r != 5)
return 0;
return 1;
}
int round_shutter(int tv, int slowest_shutter)
{
int tvr;
tv = MIN(tv, FASTEST_SHUTTER_SPEED_RAW);
tvr = MAX(tv , slowest_shutter); if (expo_value_rounding_ok(tvr, 0)) return tvr;
tvr = MAX(tv - 1, slowest_shutter); if (expo_value_rounding_ok(tvr, 0)) return tvr;
tvr = MAX(tv + 1, slowest_shutter); if (expo_value_rounding_ok(tvr, 0)) return tvr;
tvr = MAX(tv - 2, slowest_shutter); if (expo_value_rounding_ok(tvr, 0)) return tvr;
tvr = MAX(tv + 2, slowest_shutter); if (expo_value_rounding_ok(tvr, 0)) return tvr;
tvr = MAX(tv + 3, slowest_shutter); if (expo_value_rounding_ok(tvr, 0)) return tvr;
tvr = MAX(tv + 4, slowest_shutter); if (expo_value_rounding_ok(tvr, 0)) return tvr;
return 0;
}
It seems to do that in order to have shutter speed values that respect 1/3 or 1/2 EV increments (there is the same thing in lens.c but only in movie mode) so it let the choice between 4 shutter speed values for each 1EV step
if (r != 0 && r != 4 && r != 3 && r != 5)
On my Canon 550D (maybe it's not the same on other cameras) for each 1EV step, there are only 3 values possible : for exemple 1/100, 1/125 and 1/160
If I look at all my pictures, there are 4 bumps for each 1EV step (which is normal looking at the code) but there are only 3 values possible for the shutter speed in the EXIF data so there is one bump that is not repercuted in the EXIF cause the shutter speed value doesn't exist in the camera even it used by the ETTR. These non repercuted bumps happen at each stop with values like 1/50, 1/100, 1/200, 1/400, ...
Maybe the cause is the lens twist trick that let ETTR change the shutter speed value without being able to see if it's ok or not (I've seen some waiting for changes confirmation in lens.c)
But even if it's the lens trick that causes it, it would be great to let the camera only choose between the 3 values available for each step and not for 4.
Yannick
Quote from: yannick_c on May 19, 2015, 04:47:29 AM
On my Canon 550D (maybe it's not the same on other cameras) for each 1EV step, there are only 3 values possible : for exemple 1/100, 1/125 and 1/160
Change your Canon settings to 1/2 EV step instead of 1/3 EV step and you will see another possible value.
Quote from: yannick_c on May 19, 2015, 04:47:29 AM
cause the shutter speed value doesn't exist in the camera even it used by the ETTR.
This is not possible, ETTR cannot use a shutter speed that "doesn't exist in the camera". ETTR simply asks the Canon firmware to change the shutter speed (in essence, ETTR simply clicks some buttons for you). Sending the Canon firmware an invalid shutter speed can brick your camera, that's why values are rounded in ML code in the first place.
Thanks for the infos dmilligan, it's more and more clear in my head now. I've seen the 1/2 values and it seems that there are these values that are not repercuted in the EXIF data.
In the picture below, you can see the different bumps in luminance and the shutter speed values written in the EXIF. As you can see, there are bumps that are not repercuted. These bumps are corresponding to the 1/2 values. As you said, these values exist in the camera, ETTR use them, but the Camera seems unable to write the proper value in the EXIF data (and that's what I don't understand here). The Camera writes the next 1/3 value instead of the 1/2 one.
(http://108.imagebam.com/download/b_VpdLNdskiy7xsD2HiaJg/41066/410655284/Exif%20infos%20preview.jpg)
Yannick
edit : Preview clearer
I simulated a sunset timelapse with camera on tripod, and a constant light source that was moved away in small increments.
Results were as expected (6D). That is, exposure dropped as light source was moved away, until limit reached and next shutter value used. No half stops with camera set to 1/3rd.
For clarity yannick_c, those half stop bumps you marked in the image above should be at the marked exif boundaries. 1/160 > 1/180 > 1/200, but it looks like you mark 1/160 > 1/200 > 1/180 > 1/250.
Can you upload some unmolested CR2s, say from 1/160 through 1/320?
I've changed the preview for better comprehension. I'm uploading the CR2 files (1.4 Go, should be ok in 4 hours :( ) I have the original JPG also that are less big, but I think you will prefer the CR2.
I've uploaded 6 CR2 files (the first 3 that are obviously taken at shutter 1/180 (but tagged 1/200) and 3 after the bump that are tagged correctly are 1/200).
http://lets-fall.com/timelapse/Timelapse_shutter_180_200_bump.zip (http://lets-fall.com/timelapse/Timelapse_shutter_180_200_bump.zip)
I'll upload the 1.4 Go zip file with more CR2 tonight (it's 4am here).
Thanks for your help.
PS : it's a sunrise timelapse
And here are all the CR2 from shutter 1/160 to 1/320 : http://lets-fall.com/timelapse/Timelapse_cr2_shutter_160_to_320.zip (http://lets-fall.com/timelapse/Timelapse_cr2_shutter_160_to_320.zip) (1.4Go)
With your test reproducing indoor sunset, did you use the lens twist trick or not? Maybe it's the fact that the lens is disconnected that lets the ETTR module choose a shutter speed with 1/2 stop (even if the camera is set to 1/3rd). I don't remember hearing 2 beeps (just 1 beep) when ETTR changed the shutter speed value during my timelapse, it could be due to a non confirmation of the new shutter value by the lens.
The lens has nothing to do with the shutter and the lens does not "confirm" shutter speeds, so this explanation is unlikely.
One beep means that ETTR settled on a solution, two beeps means that another iteration is probably needed, three beeps means exposure limits reached.
Hi,
I tried to see what I can find in the EXIF Data (from Jeffrey's Exif Viewer online here : http://regex.info/exif.cgi (http://regex.info/exif.cgi))
I've uploaded the 2 jpg pictures where a bump happens between "assumed" shutter value of 1/180 and the next at 1/200 (the 2 pictures from the preview)
First, I didn't think that there were so much informations stored, there's a lot of interesting things.
Here what I've found in it (1st value for picture assumed taken at 1/180, 2nd value for picture after the bump to 1/200)
EXIF
- Shutter Speed Value : 1/197 - 1/197
- Exposure Time : 1/200 - 1/200
MakerNotes
- Target Exposure Time : 1/203 - 1/203
- Exposure Time : 1/181 - 1/203
- Exposure Time : 1/197 - 1/197
Composite
This block of data is computed based upon other items. Some of it may be wildly incorrect, especially if the image has been resized.
- Shutter Speed : 1/200 - 1/200
I don't know what these MakerNotes are and why there are 2 lines with Exposure Time but you can clearly see that the first is taken at around 1/180 and the second at around 1/200 even the two are tagged 1/200 in the EXIF Data.
I've tested with 3 pictures before and 3 after the bumps. The 3 before have that line "Exposure Time" = 1/181 and the 3 after have "Exposure Time" = 1/ 203 in the MakerNotes
Here are a zip with the jpg pictures (3 before the bump, 3 after) like the 6 CR2 I've uploaded before : http://lets-fall.com/timelapse/Timelapse_shutter_180_200_bump_original_jpg.zip (http://lets-fall.com/timelapse/Timelapse_shutter_180_200_bump_original_jpg.zip)
If there's nothing that can be done to get the correct value from camera, maybe an easy script could replace the wrong EXIF data with that correct stored value and write it in the xmp file.
Yannick
EDIT : the correct Shutter Speed Value is easily found with exiftool with the tag -Makernotes:ExposureTime
I have found a way to correct all my .CR2 EXIF Data with the correct Shutter Speed Value with a simple line of code :
exiftool "-EXIF:ExposureTime<Makernotes:ExposureTime" CR2_Directory
where CR2_Directory is the folder with all my CR2 files.
Maybe it's not the best to directly change the original CR2 source file like that ?
Here is the LRTimelapse preview for luminance (pink curve) with both non corrected and corrected EXIF shutter speed info.
(http://105.imagebam.com/download/BCYfRnp81Iwd67MnMID9Eg/41083/410827192/LRTimelapse%20luminance%20corrected.jpg)
LRTimelapse HolyGrail correction still have some problem when ETTR changes values every 1,2 or 3 pictures (the big bumps at the center) but if you look at the second part of the curve, it's more smooth now and the weird bumps with the 1/2 EV shutter values have now disapeared.
LRTimelapse will then do the job deflickering the all sequence (even with the non corrected version), but it's still better to start from right exif values (even if I don't know if the 1/181 and 1/203 are really the "real" exposition time but it's more accurate than 1/200 which I had before for both).
Hi everyone!
I'm pretty new to timelapses, but i have been using auto ettr successfully in the last weeks. My Question is: Is it possible to set a minimum aperture for the ettr tool? I'd like to get the maximum sharpness with my standard objective and thats just not possible at the widest open aperture.
camera: canon eos 600D
Any Tips would be great.
Paul
@Paul: auto ettr did not change aperture.
Hi, I use EOSM. I have a suggestion for AETTR in ML.
Like Bulb Ramping, can you add a Sunset/Sunrise option to let the exposure only decrease/increase?
I got some terrible flickers during changes occasionally. Say 4" to 5", it's like "...4,4,4,4,5,4,5,4,5,4,5,5,5,5..."
I have a problem during a sunset sequence in the city. It's hard to get both day (sunset) and night exposures correct.
In the beginning, both Highlight Ignore and SNR limit affect the brightness of a picture.
However, when night comes, it seems only SNR limit affect the brightness.
It matches the wiki: SNR has higher priority, but there comes a problem.
(I found that Shadow SNR didn't affect exposure as much as Midtone SNR. So I only discuss Midtone SNR below.)
With 5EV, it's ok at daytime (sunset), but too bright at night, inducing too much clips of city lights.
If I use 4EV instead, the clips are ok, but it's way too dark at daytime, even darker than a normal 0EV exposure.
City lights always have clips at night. If clips are too much, it's doomed. I can't control it now because of the priority.
I guess this can be solved if I can set Highlight Ignore with higher priority than SNR.
Is this conclusion correct? Or am I wrong on some points/settings which lead to the failure?
If the conclusion is correct, can you add a priority option on this? Thanks!
@gmr20
I believe the issue you are experiencing is one I found, which resulted in me 'restricting' ETTR by NOT using the SNR options.
I must emphasis that this in my workflow: it is nether right or wrong :-)
By using the SNR settings you are giving control to ML, ie SNR will force greater clipping etc.
IMHO the power of ETTR is to expose to the right WITHOUT clipping. If you use the SNR settings, you are not really using ETTR but a superior form of 'balanced' exposure control.
I am an ETTR purest, and hence I keep the two SNR settings at 0, and only use the clipping % and, if required, Dual-ISO.
Finally, as usual, the above is my experience and workflow. Others may disagree :-)
If you enable link to dual ISO, you should get the best of both worlds under most exposure conditions, not blown highlights, and less noisy midtones/shadows.
A nighttime scene with city lights is going to have an extreme dynamic range. You can see this when you try and use SNR settings. To get the same SNR in the midtones (as a daylight scene) means overexposing the lights. If you use dual ISO linking, you may be able to use the same SNR settings for day and night, without blowing the lights.
Hi,
i wanted to test ETTR, but it does not (70D).
(http://www2.pic-upload.de/img/28856414/VRAM2.png)
(http://www2.pic-upload.de/img/28856412/VRAM3.png)
(http://www2.pic-upload.de/img/28856413/VRAM4.png)
regards
starbase64
Try M mode ...
Same problem...
Restore ML defaults, activate ETTR module (and no other) and retry in M mode.
@Walter Schulz
always same problem...
Turn off ETTR, take a pic and link it here. Link contents of ML\Settings, too.
@Walter Schulz
Dropbox: https://www.dropbox.com/sh/3xufcfmjmoi6u0l/AAA6dUx25MYJGXPy_vbwvBPaa?dl=0
Cannot detect anything smelling fishy.
I suggest restoring cam to factory defaults via Canon menu. Don't forget C.Fn settings. If it doesn't work after (I'm afraid it won't) I'm out and must ask nikfreak to solve this riddle.
Thank you for your time...
Is it just the "Press SET" trigger mode that doesn't work? Do any of the other trigger modes work? Does press set work if you are already in LV? Do raw zebras/histogram work correctly in LV and QR?
This sounds like a bug - can you mention it in the 70D thread?
There are a few code paths that could return this error, so I'm not yet sure what's wrong.
@dmilligan
trigger "auto snap" with image review works
What is the best way to use Auto ETTR with a Controller plugged in?
I just bought a Rhino Timelapse slider with motion. http://rhinocameragear.com/collections/time-lapse-sliders
The motion controller for the slider syncs with the camera Via Bulb Mode on the Canon 6D. I want to use Auto Ettr for day to night shots, but i also bought the slider to add motion to my timelapses. Anyone know if there is any possible way of enabling Auto ETTR to work in Bulb Mode?
As of right now The slider doest sync properly in Manual Mode. And i am not sure if they will ever update the firmware for that.
Usually my workflow is to run a timelapse with Auto Ettr and then do a pass of Deflicker in Bridge in post before i export a video.
Do you think if i just shoot a timelapse with no Auto Ettr the deflicker pass in post will be enough to compensate for flicker?
Any help or workaround would be greatly appreciated. THANKS!
I have a quick question. I'm using ettr for sunset into night timelapses. It's worked amazing so far especially with the de flickering bridge script. But I ran into a problem i'm not sure that can be solved without stopping the intervalometer and turning ettr off after the sun sets. After the sun sets, and after twilight it starts to push my iso to 12,500 which I don't want at all. Is there a way to limit it? idealy I would like it to stop at 30 second exposures at iso 800-1200. Is there a way to do this?
ETTR uses maximum auto ISO limit from Canon menu (I know, not completely obvious).
I have been trying to use ETTR and it has been frustrating. Note I'm using a 70D beta-3 22/Dec version of ML.
The Wiki page (http://wiki.magiclantern.fm/ettr) says that you can use either Av or M mode:
"2. Put the camera in manual M mode or Av mode (either one since you must the aperture yourself), and set ISO to any number except in Auto. It wont work in auto! "
After much frustration using Av mode, I came across the following in the forum:
(http://www.magiclantern.fm/forum/index.php?topic=14948.msg144930#msg144930)
"- Put your camera to M and manual ISO."
I tried that (M mode) and tings got much better.
So which is correct? Should Av mode work? It seems like it should, but.... no joy when I try to use it.
Thoughts?
Thanks!
John P
I'm playing with ETTR right and I'm trying to use the Half Double Click mode. Sometimes when
I do the double click, ML does the exposure evaluation and is ready for me to take my photo.
Sometimes I do the double click but it does not trigger the exposure evaluation. If I change to
using the Set button, every time I push it it works. Half-Double Click? many times it works, many
times it doesn't.
Any ideas why Half Double Click is finicky?
I'm using the 12/23 70D Beta firmware.
Thanks!
John P
John
I also came to that conclusion and that is the reason I use SET.
I find half-shutter too 'finicky' as you say :)
Cheers
Garry
Ironically, the ETTR explanation in the ML user guide is critically flawed. lol
Feel free to replace flaws with wisdom.
hi
just getting my head around this so sorry if its basic stuff,
canon 5dmkii,
using the set button i get an "ettr failed" message no matter what settings i change, it is working in snap and always on mode,
when you have the link to dual-iso feature enabled switched on, am i correct in my understanding that it will only use the dual-iso feature if required? for this i am thinking of workflow, if half a set of images are dual-iso and half are not,
If I'm understanding this correctly, the ETTR function adjusts both shutter and ISO. You set the minimum shutter speed in the settings and it determines the optimal settings. How does this compare to setting both shutter and aperture and using Auto ISO from an image quality perspective?
Im having issues with ETTR set to always on when using the new 3.5k mode (5x zoom) in the experimental croprec build. It doesnt adjust.
Any ideas? Setting it to "SET" works fine but i noticed that it zooms out from the 5x, then back. Perhaps its not compatible with zoomed liveview recording modes?
Im using the 5D III and magiclantern-crop_rec_4k.2017Oct16.5D3113
I'm a little bit confused using AV Mode on 6D. Does ETTR only works on M Mode?
Wiki says 'Put the camera in manual M mode or Av mode'
What about drive modes. Can I use Silent mode or self-timer for ETTR?
It used to work in Av, but results were far from great (it was more like two very different metering methods fighting each other).
All drive modes should work fine, as long as you don't expect metering during a burst sequence (for now).
Thanks for answer...
What is that supposed to mean?
'the image is displayed in the LCD monitor with an analysis of the image'
On CHDK I used a RAW meter which analyzed the raw data with a histogram on 14bit RAW Data. The exposure for the following shoots has been corrected with this information. Is this something similar?
If in doubt, check ML help at the bottom of screen (that one is usually up to date).
Yes, this adjusts exposure for the next image, based on the raw histogram of previous image. Alternatively, it can meter from LiveView, but that's a bit of hit and miss, as raw exposure in LiveView doesn't quite match the one from CR2 and the exact amount may be model-specific.
I'm doing some tests with Auto ETTR, but It's resetting the slowest shutter by itself, I'm not sure why though.
Using on Canon 6D 1.1.6
Tried with nightly build feb04 and experimental 10bit_12bit jan31.
Both same result, here's what I'm doing.
Active ETTR, go to live view set the slowest, (ettr<=10" displayed on screen) take 1st shot, all good displays that it's settled to(...) but after taking a couple while moving (3-4) it changes the slowest shutter speed to the current speed and starts going up on the iso.
Hope this is clear, any idea what I'm doing wrong?
Thanks
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If you upload some LiveView frames (simple silent pictures) from the LiveView scene you are metering, it might become clear.
Best guess: at long exposure times, it might have something to do with how Canon code implements exposure simulation. It's hard to preview a 10-second exposure from a 1/30 LiveView frame, let alone meter the optimal exposure from it. If, after a certain exposure level, the LiveView does not brighten any more, or if the brightening is applied in the processing pipeline after the raw data (happens at very long exposures), Auto ETTR may believe the image is underexposed and keep raising the exposure settings. One such register was recently identified (https://www.magiclantern.fm/forum/index.php?topic=10111.msg191218#msg191218), but ETTR wasn't updated to make use of it.
For long exposures, try metering from actual images (outside LiveView).
If you are not metering a long exposure, the white level might be wrong; in this case, please run this test:
http://www.magiclantern.fm/forum/index.php?topic=16054.msg195395#msg195395
Quote from: a1ex on April 07, 2018, 03:18:58 PM
If, after a certain exposure level, the LiveView does not brighten any more, or if the brightening is applied in the processing pipeline after the raw data (happens at very long exposures), Auto ETTR may believe the image is underexposed and keep raising the exposure settings.
Yeah I though of that but actually i'm not doing 10 second exposure i'm just setting the maximum slow shutter for the AETTR, and the prob is that when the image gets a bit dark instead of having slower shutter speed it's resetting the value I set it in the begging and it's raising the ISO. I also tried setting it to 6 sec as slowest shutter speed same thing.
That raises another question, if it took a long exposure and the LiveView does not brighten any more doesn't it check the RawHistogram of the preview image after that? (histogram set to "Raw RGB" in "draw all modes" and the "Raw EV indicato"r to "ETTR hint" mode and i have 2 sec preview) or am I just mixing everything up now?
I'm not sure what u mean with the white balance @A1ex, the images seems fine when I open them no pink pixels on anything weird.
I have a question if the overall exposure changes quickly in like 3 images could that be the reason it's behaving like that?
Thanks again for you time
ok if I disable "link to canon shutter" and set the slowest shutter manually it works perfectly
What does the 'ETTR failed' message really mean? Does it mean that the algorithm simply cannon find an optimal setting for the scene, or that there is some genuine module error involved?
Checking the source, there are a variety of possible causes. The relevant code is in modules/ettr/ettr.c
There are some early ways to hit this error, shown here (similar in auto_ettr_on_request_task_slow()):
1122 static void auto_ettr_on_request_task_fast()
1123 {
1124 ettr_beep();
1125 int raw_requested = 0;
1126
1127 char* err_msg = "ETTR failed";
1128
1129 /* requires LiveView and ExpSim */
1130 if (!auto_ettr_prepare_lv(0, 1)) goto err;
1131 if (!auto_ettr_check_lv()) goto err;
1132
1133 if (get_halfshutter_pressed())
1134 {
1135 msleep(500);
1136 if (get_halfshutter_pressed()) goto err;
1137 }
There are some later ways too but that's too complex for me to try and list.
Unfortunately, that doesn't explain much to me. The thing is, I'm trying to make a FRSP timelapse with DualISO. And the way ETTR turns DualISO on and off seems inconsistent (like, three shots 20 seconds apart, the first and the last ones has DualISO while the middle one doesn't). Since I can't get any kind of log, I suspect that the ones without DualISO are probably the ones with 'ETTR failed' (because that's what I get in regular photos where ETTR fails - no DualISO setting).
Well, I answered your original question: the error message can have multiple causes, and they are complex.
It sounds like your actual problem is more likely something in DualISO than ETTR. Maybe some interaction between the two? I don't have any direct experience with either of these so I can't help, sorry. If you know a little C you could add some logging.