Problem: irregular timing with Intervalometer/Bulb Ramping on 5Dmkii

[AndyB]

Hi there, I am new to this forum, and to Magic Lantern, so apologies if this query is posted in the wrong place.

I have a ML problem, and I would love to hear if anyone else has experienced this and what any thoughts you might have on the issue.

In short, when shooting timelapses with the Intervalometer and Bulb Ramping options the timing of the shots frequently goes haywire, missing a shot, then seemingly firing the next two off in quick succession as if trying to catch up.

The other night I had the Intervalometer set for 5 second intervals. There would be frequent intervals during the shoot when the timing of the shots would go something like this: 5s, 5s, 10s, 3s, 2s, 5s, 5s...etc. You get the idea. The end result is a stuttering effect in the timelapse which is distracting and also renders the sequence useless.

I don't think that this is a problem with not being able to write to the card quick enough. I am using a 5D mkii with a 32Mb SanDisk Extreme 60mb/s UDMA CF card, and there is no bottleneck with writing the raw files to the card.

I am using ML version 2.3.5D2.212.

If anyone has any thoughts I would appreciate hearing from you.

Cheers,
Andy

[a1ex]

This happens when snapping a picture takes longer than intervalometer delay.

Did you have some sort of noise reduction enabled? this takes time.

[AndyB]

Long Exposure Noise Reduction was off, as I never use it.

The exposure times ranged from 0.125 to 1 second for the majority of shoot (it was sunset/twilight), so I would be surprised if ML didn't have time to do its stuff after the image had been written to the card.

If it turns out that there is a minimum amount of time that ML needs to compute the Bulb Ramping data and set the exposure for the next shot then fair enough, I can work with that. I would just like to know what it is though!

On the other hand, 5 seconds is really a very common interval for timelapse stuff so I am surprised that I experienced these issues.

Anyway, thanks for your comments and thoughts, Alex.   

[filmthatsheet]

I recently posted a question about this.  I was experiencing the same thing with AutoETTR Always On.  No noise reduction was activated.   Pictures were 10 seconds apart with my shutter no slower than 1 second.

Have there been any developments regarding this issue?

[a1ex]

I've tried it right now:

5D2, auto ETTR, M mode, shutter speed 2 seconds, raw zebras, raw histogram, post deflicker on or off, around 50 test shots.

Timing was perfectly consistent. The intervalometer countdown was starting from 5 seconds, so there was plenty of idle time.

Can you record a video of the camera screen that shows the issue?

[filmthatsheet]

This was the best I could do...  I held up my macbook with an online stopwatch running next to my camera. 

http://youtu.be/xIknZYbnvk8

The moment where I start the stopwatch is approx 5 minutes after I started the intervalometer.  You can see that it progressively takes longer and longer (never noticed that before) and that's probably what happens before my camera gets into it's strange cadence.  Not quite as sporadic as the other guy's camera, but more like... 

10 sec, 10 sec, 10 sec, 14 sec, 2 sec, and repeat... 

What I've noticed is that there's always a photo that's taken quickly (about 2 sec after the one before it) right after the first noticeably delayed photo.  In this example, I only let the camera run for about 7 minutes, and did not experience the weird "delayed shot/quick shot" issue.  When I noticed it originally, it was after running approx 20 minutes with the same settings a few days ago.  Didn't have time to do a lengthy test. 


Sidenote.. While I was exporting the video above, camera started up again out of the blue.  I had accidentally left it on after I stopped the timelapse.  15 minutes later... http://youtu.be/ODJOgqSqqus

[a1ex]

Fixed the 11-second waiting instead of 10 (was caused by post deflicker running with a very high priority - so the internal clock was no longer updating while post deflicker was running). This bug also tricked me into thinking that post deflicker only needs 0.12 seconds to run, when it was requiring around 1 second.

Could not reproduce the irregular cadence though. Here, it was taking a picture every 11 seconds, but it was regular.

About camera starting up again... that's very likely a sign of memory corruption. That's going to be hard to troubleshoot, but if you can find a way to reproduce it, will help a lot.