Timelapse Questions

Started by limey, November 08, 2016, 11:34:25 PM

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limey

I have a lot of experience shooting timelapses with ML now for a few years. However, I'm about to embark on a month long timelapse. I think the cameras (3) will run 24 hours a day with plugin adapters.

What I want to know is will AutoETTR be the best method? I have done some timelapses where the AutoETTR looks like its failing and not adjusting the exposure properly. Particularly from daytime to Sunset. Is it something to just keep the faith in and let it be or will it need to be massaged?

limey

Additional info. These cameras will be largely unmanned for the month, however, I plan to check on them every 3 days. I'm wondering if a timer on the outlet would be a good idea since no activity will occur at night so no point firing shots.

If I used this timer, would it not allow the timelapse to restart when the power came back on? Unfortunately I don't have time to test it.
https://www.amazon.com/Enover-Programmable-Digital-3-prong-Appliances/dp/B0191ZGELS/

PaulHarwood856

Hey limey,

     I'm not quite sure about the second post, but if you shoot time lapses with ML, I would enable Post DeFlicker if you can. This might be able to fix any issues that come up with Auto ETTR. Also, have you considered HDR video at all? For extended dynamic range?

- Paul Harwood

a1ex

Figuring out how much to adjust an overexposed picture is much harder than the other way.

Therefore, you may want to underexpose a bit (reduce exposure target, increase highlight ignore) and use the SNR limits for shadows and midtones (they are easy to meter and statistically robust).

Mixing dual iso will most likely give trouble; either keep it enabled at say 100/1600 all the time, or keep it off (this depends on whether you will have DR issues with your scene). Keeping it off is probably the best choice.

The longest ETTR timelapse I've tried was about 24 hours.

The intervalometer auto-restarts when power gets back. If you will cut the power, make sure modules will reload after a crash (Debug menu). Also make sure you will not be cutting the power while saving an image to card (this may cause problems with the filesystem and result in data loss - didn't try).

Maybe it's best to have a backup camera in auto mode.

If you can attach some images where ETTR failed, I may be able to give better diagnostics.

The CHDK forum also has very good advice on very timelapses. Starting points:
https://chdk.setepontos.com/index.php?topic=6764.0
https://chdk.setepontos.com/index.php?topic=11437.0

Another possible issue is overflow in internal timers. CHDK workaround is to restart the camera periodically:
http://chdk.wikia.com/wiki/Ultimate_Intervalometer#Days_between_resets
https://chdk.setepontos.com/index.php?topic=9969.msg124791#msg124791

I didn't do any timer overflow handling in ML, but shutting down the camera at night should already take care of this.

limey

No dual iso for sure don't want to deal with the extra post processing.

I'm wondering if I should shoot live view or not. The timer idea is interesting if it works it could be huge.

a1ex

LiveView will heat up the sensor (more noise) and will double the number of shutter actuations if you are not using Canon's silent shooting mode (since the camera must return to LiveView after taking each picture).

It will also affect ETTR metering if you choose Always On (metering on the LiveView image instead of the previous still image). This may help if exposure changes a lot (as it will get a chance to try various exposure parameters until it settles), or may hurt in low light (it's hard to meter a long exposure from a 1/30s LiveView frame).

limey

Quote from: a1ex on November 09, 2016, 05:27:45 PM
LiveView will heat up the sensor (more noise) and will double the number of shutter actuations if you are not using Canon's silent shooting mode (since the camera must return to LiveView after taking each picture).

It will also affect ETTR metering if you choose Always On (metering on the LiveView image instead of the previous still image). This may help if exposure changes a lot (as it will get a chance to try various exposure parameters until it settles), or may hurt in low light (it's hard to meter a long exposure from a 1/30s LiveView frame).

Great tips. I am not using live view on this project. I switched the cameras to silent mode as well.

Additional question that might be magic lantern related it might not be. I have three cameras running continuously for the next 22 days. Everyday I go and check the cameras and notice they are turned off. Is there anything in ML and the intravalometer that would turn the camera off? Seems to be happening after around 15hrs of shooting.

I have the camera set to not shut off on the canon menu - that wouldn't be this anyways, but just saying.

I was also wondering if it's the power source which is a Chinese knockoff dummy battery power AC adapter.

These 3 cameras are running 1.23.


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a1ex

Shouldn't happen. Was it normal shutdown or crash?

You can tell the difference if you choose not to load modules after a crash.

If you send me a copy of the ML folder from your card, I can try to reproduce it.

limey

Hmm I don't have any of the cameras handy as they are at the place shooting right now and started new timelapse this morning.

I have a new theory though.

Looking at two different cameras the time lapses are stopping once they reach 9999.

However, I see now that this may be only one reason the camera stopped. As one camera turned off well before hitting this number.

When I go there tomorrow I'll swap the sd card. I'm sure the camera will turn off again.


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limey

I didn't have to reenable modules so I assume it was regular crash or potential power outage or these power supplies are failing around the 15hr mark.

I ordered new power supplies I'll be able to test on Monday to rule it out.


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limey

Here is my ML folder.
https://www.dropbox.com/s/x2slyxcjii90vfv/ML.zip?dl=0

What I'm seeing is either around the 15-16 hour mark or 4000+ shots the camera shuts off.

a1ex

Quote
I didn't have to reenable modules so I assume it was regular crash or potential power outage or these power supplies are failing around the 15hr mark.

If there is a power outage, ML can't tell the difference and will consider it a crash. Since you didn't have to re-enable the modules, the camera was shut down cleanly. Figure out why...

Quote from: limey on November 13, 2016, 07:13:35 PM
What I'm seeing is either around the 15-16 hour mark or 4000+ shots the camera shuts off.

My timelapse attempts didn't exceed about 1000 frames (a 64GB card can store about 2000 frames), but some of them were longer than 24 hours. Both regular and silent.

The longest one was from 01/07/2016 5:40pm to 04/07/2016 08:30am, 1109 frames (CR2). I've used 5D3 1.1.3, Auto ETTR, Dual ISO (mixed with regular pictures, as decided by ETTR). Didn't manage to develop the timelapse yet, but there were no crashes or unexpected events on the camera side.

limey

Is there a difference in what type of power outage would cause a different reaction in ml?


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a1ex

Both taking the battery out and plugging out the power adapter would be interpreted as a crash (because ML shutdown sequence doesn't run). Repeating the action will not change the outcome.

I'm not sure what happens after an ERR screen if left for a long time (if the camera restarts automatically, it will most likely be a clean shutdown, but you should see an error log on the card).

limey

I just replaced the dummy battery power supply with a better brand.

If I decided to try the canon intravalometer, could use that in conjunction with auto ettr or does the 3pin intravalometer screw up magic lantern? If it works I might try this and bypass the ml intravalometer.


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limey

Update: power supply seems to be the culprit. Now my next issue is the cards aren't auto switching despite that being set to on.


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a1ex

Quote from: limey on November 16, 2016, 02:58:41 AM
If I decided to try the canon intravalometer, could use that in conjunction with auto ettr or does the 3pin intravalometer screw up magic lantern? If it works I might try this and bypass the ml intravalometer.

Didn't try, but I don't see why it wouldn't work. ETTR is triggered by the Quick Review screen after taking a picture.

Quote from: limey on November 16, 2016, 04:01:22 PM
Now my next issue is the cards aren't auto switching despite that being set to on.

Reproduced.

The issue is that Canon firmware reports 0 pictures available in the buffer, and ML waits for a non-zero value before attempting to take a picture. However, this check times out after about 1 minute, and the card gets switched.

limey

I'm seeing Err 4 - which equals card full.

Based on your reply above the cards should switch, however, they are not. I wonder if it's because i have the preferred card set to CF.

limey

So to clarify: ML can't auto switch the card as it fills up one card while running the intravalometer?

a1ex

Works fine here; the only issue is a 1-minute delay in the process.