Alright, now you have true RAW histogram and zebras. 5D2 only.
Very cool. Great work.
Would it be possible to have "Automatic ETTR" capability? It would perhaps select the maximum exposure that only blew out one of the RGBG channels. That would let ACR PV2012 do its magic at a near optimal level.
The photographer would obviously be responsible for not including a specular highlight, such as the sun or chrome, etc.
For my "use case" on panoramas, I'd pick a bright frame that excluded specular highlights, determine the suggested, automatic ETTR exposure from ML, and then set the camera on Manual with that exposure.
And what would ML adjust to increase exposure, shutter, aperture or ISO? You might be happy with ISO, others with shutter etc.
I don't see how this would be much faster then doing it in live view.
And what would ML adjust to increase exposure, shutter, aperture or ISO? You might be happy with ISO, others with shutter etc.
Got it working.
This will probably convince me to shoot in auto ETTR, because it exposes exactly the way I want.
Going to try it this weekend at a small local event.
If your picture is overexposed, it has no way to know by how much. So, start with an underexposed one and will get it right in one step.In big changes of light it take three steps. When I go from dark ground to something with sky it takes three shots.
rename 's/UFR$/ufraw/' *
ufraw-batch *.ufraw --out-type=jpeg
I've got a question on the RAW histogram. So as I understand, before that the histogram was created from a jpg-like presentation...so you didn't get an idea of the headroom which you are able to recover in the shadows / highlights. Is it right, that now in the RAW histogram it shows the whole range of information? That would be so much better. ^^
Auto ETTR needs just a little bit of time, is it already optimized for speed? Maybe it would be helpful when there is a indicator that the Auto ETTR "has just set the values". Like a beep or something.
Auto ETTR can be assigned to some shortcut, but I'm not sure which is the best way to do it. The * button is hard to detect, we can't tell the difference between it and half-shutter.
Another tip: combine this with Post Deflicker from shoot menu. This one will save exposure compensation info in sidecar files, so when you develop the raw shots, all your pictures will appear equally exposed.
Greetings, I was hoping that someone could tell me how to implement the auto ETTR feature on the 500d, I am using the latest nightly and could not find the feature in the menus. Thanks so much to all the devs who work on this awesome software.
NOTE: If you set your intervalometer at 30 seconds and your slowest shutter speed at 30 sec, you will have problems. Set the intervalometer at least = Slowest Shutter speed plus the review image setting, in Canon Menu, plus 3 more seconds.Would it be possible, to change the interval during the course of a shooting? So i start during daytime with short intervals, giving a lot of frames to work with and only if the shutter gets to slow, the intervals get longer.
Shouldn't the midtones be 13-18% luminance? 3EV below important highlights.
How it works:
- If the midtones get too noisy, the ETTR algorithm will stop underexposing.
- Same thing if the shadows get too noisy.
I have the histogram always enabled for that (the ETTR hint from there uses the parameters from auto ETTR).
Canon exposure value is not much better than random from what I've noticed. But you can use it, just flip to some auto mode.
The histogram is there in photo mode too.
But you can use it, just flip to some auto mode.
I prefer to let the user choose whatever settings he wants, and just print a warning.In C1 (shutter priority) if I put ISO in some manual value, then AutoETTR module does nothing and reaches a limit. If I flip to Auto ISO then AETTR works but Midtones and Shadows system does not work.
The hardest part is to think where I should put that in the menu.
In C1 (shutter priority)
Um, just add a Tigger Mode "Always warn" with the help line explaining that it beeps when the highlights are blown according to the ettr settings? The decisive part for me here is that I'd not need to look away from the vf.
Try Tv mode rather then a custom mode.
Good idea. Being able to set a warning for the midtones/shadows would be very handy too.
Just started playing with this one and I may be missing something ...
Id like to use it instead of Canon's metering all the time, it is something I was reading about before ML and it's a great feature.
Maybe something like "adjust settings if Canon meter shows a difference of 2 stops or more" would work better. If any of you wants to try, I can share a patch.
From a photography standpoint, autosnap is probably the best option to use. If your exposure settings were already correct before autosnap, you get your photo. Else, you still get photos while AETTR is doing its calculations. ie: You don't miss your moments.
Is it possible to change the "Link to Dual ISO" option so that it'll use Dual ISO just for ettr pictures and not for the ones taken with out ettr without having to go back to the menu to turn Dual ISO on and off every time?
I have 6d 1.1.3 (October) Tragic Lantern, but in ETTR settings I dont find Shadow SNR and Midtones SNR... Anybody knows why???
The only way it can do so is by increasing the ISO to ridiculous levels (3200, 6400), which kind of defeats the purpose of avoiding noise.
on-topic: change auto ISO limit in Canon menu.
I have yet to see a higher ISO noisier than a lower one (in electrons).
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.
Can someone explain why the option is not available.The camera behaves differently when in these modes and so they would need to be reverse engineered (like everything else in ML).
PaulJBis: You said in your post above that you "just finished another sunset timelapse using AutoETTR, and at the end (when it was dark), it blew my highlights to the point that now I can't recover them in post. Thus, I'd like to know if there's a way to ramp EV so that, at the end of the timelapse, the software aims for a different value than at the beginning."
When you say "ramp EV exposure," are you talking about the "Exposure target" parameter in AutoETTR? How have your sunset/sunrise timelapses come along so far with AutoETTR? I'm trying to learn all that I can so any help or tips would be appreciated.
Can/does this apply when recording raw video?
a) will ettr always ensure we capture a good exposure and
b) will going over ettr allow us to reduce exposure in post and give a better image?
Also, can't get LE-ETTR to trigger in M mode.
PS half press doesn't trigger in M mode
do a full shutter press if you are in M
Bulb timer doesn't get reset after an LE-ETTR capture.
Higher ISO is noiserSounds like you didn't read the link a1ex posted in the previous response.
I have some problem, when I using ETTR with 1/2 stop for shooting timelapse and postprocess it with LRTimelapse. LRTimelapse can work only with step 1/3 stop. Can I change some settings ETTR for change step from 1/2 to 1/3?
The smaller the steps, the better the results
The transition between day and night is more smooth.
That said, we have our own deflickering tools that do not use the EXIF info at all. Some examples:
- Deflicker module (http://www.magiclantern.fm/forum/index.php?topic=10496) (original version, not very practical, as deflickering is best done in post)
- Bridge script (http://www.magiclantern.fm/forum/index.php?topic=8850) (similar algorithm, but requires proprietary software)
- mlvfs --deflicker (http://www.magiclantern.fm/forum/index.php?topic=13152) and mlv_dump --deflicker (http://www.magiclantern.fm/forum/index.php?topic=18975) (for MLV timelapse, e.g. silent pics or raw video)
The same deflickering algorithm is available in Darktable.
You'll have to change the code, and it's not trivial. You'll need to disallow 1/2-stop exposures and account for the rounding used in 1/3-stop mode (actually 3/8 and 5/8).
For me, the end goal is not to provide a finished product that everybody can consume. I'd rather see it as an open software platform where others can program their own enhancements and share them with the community
Exposure matching is exposure matching. Doesn't matter how different the images are, whether those images are captured with 1/3 stop or 1/2 stop exposure settings
If I were to create these recordings with ETTR then you could probably correct it but then I would lose a lot of information especially in the dark areas.
Last week I had some time to play with ETTR and I think I've found a way to avoid the severe underexposure in scenes with high dynamic range (e.g. like this (http://www.magiclantern.fm/forum/index.php?topic=7835)).
https://bitbucket.org/hudson/magic-lantern/commits/fcdc23eb5d7d
How it works:
- If the midtones get too noisy, the ETTR algorithm will stop underexposing.
- Same thing if the shadows get too noisy.
How to quantify "too noisy"?
For midtones it's easy: 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.
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.
Keep in mind that 5% is bigger than you may think, since it refers to image area, not linear size. The linear percentage is roughly 22% (1/4.5).
So, you can choose 2 noise limits, one for midtones and one for shadows, and the image will not get noisier than that (but you may lose some highlights). This setting has the highest priority, so it will sacrifice highlights even if you disallow clipping from the other settings.
I'm not yet sure what are some good defaults for this new trick, so it's turned off by default.
if (overexposed_percentage > 0 && (auto_ettr_midtone_snr_limit || auto_ettr_shadow_snr_limit) && !dual_iso)I enabled DualISO, to test, whether this is the source of problem - and it disappeared. What i found: as long, as i reduce light, the image on LCD gets more pixelated,
If you have attempted to meter long exposures from 1/30" LiveView frames... I'm not sure what I can do.Yes, it's seems that is the point: ETTR (not me) tries to calculate exposure from that mess.
I think it's unnecessary to upload the perfectly black DNG.
if (!lv)
{
if (is_module_enabled("silent"))
{
/* at ISO 160, 320 etc, the white level is decreased by -1/3 EV */
/* in LiveView, it doesn't change */
int iso = 0;
if (!iso) iso = lens_info.raw_iso;
if (!iso) iso = lens_info.raw_iso_auto;
static int last_iso = 0;
if (!iso) iso = last_iso;
last_iso = iso;
if (!iso) return 0;
int iso_rounded = COERCE((iso + 3) / 8 * 8, 72, 200);
float iso_digital = (iso - iso_rounded) / 8.0f;
if (iso_digital <= 0)
{
raw_info.white_level -= raw_info.black_level;
raw_info.white_level *= powf(2, iso_digital);
raw_info.white_level += raw_info.black_level;
}
raw_info.white_level = autodetect_white_level(raw_info.white_level);
raw_info.dynamic_range = compute_dynamic_range(black_mean, black_stdev_x100, raw_info.white_level);
}
else
{
/* start at Canon's white level, and autodetect from there
* Canon's guess may be up to 0.38 EV below the true value - or maybe more?
* http://www.magiclantern.fm/forum/index.php?topic=20579.msg190437#msg190437
*/
int canon_white = shamem_read(0xC0F12054) >> 16;
raw_info.white_level = autodetect_white_level(canon_white);
raw_info.dynamic_range = compute_dynamic_range(black_mean, black_stdev_x100, raw_info.white_level);
printf("White level: %d -> %d\n", canon_white, raw_info.white_level);
}
}
That fixes the problem, but... now it occasionally ens up stuck with "Raw error". now it occasionally ens up stuck with "Raw error".
else if (QR_MODE) // image review after taking pics
/* for debugging: if black check fails, save the bad frame as DNG */