[SOLVED] 5D III Pulsing RAW images

Started by markodarko, May 19, 2016, 12:18:19 AM

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markodarko

UPDATE: It is definitely to do with Exposure Override when at certain apertures (f/6.4 & f/4.5 for me). Easiest solution is to ensure that you have Exposure Override set to "OFF" and you shouldn't come across this problem.

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Hi guys,

After a search all I could find on pulsing images was a long time ago here and that seemed to be for H.264.

Having just returned from a day's shoot (in the rain) for a short film I'm working on, I was disappointed to see that a long shot (a 3 minute shot of fields and clouds) was "pulsing" at around 100bpm (according to my tap tempo metronome) in MLRawViewer. So, I thought I'd see what it was like after conversion in AE, and same problem.

It's not a "flickering", it's definitely a "pulsing" phenomenon so MLVFS's deflicker feature doesn't seem to do anything with it no matter what values I put into the deflicker box.

So, a couple of questions, if I may...

1. What I would like to know is the cause of this so that I can avoid it in future. According to the link above it's to do with setting Exposure Override to "ON" and using specific aperture settings. Is this correct? If so I'll just set that to "OFF" and not worry about it (I have currently got it set to ON). However, if it is something else then I'd appreciate it if someone could provide pointers for how to avoid this pulsing in future as the footage I have as it stands now requires a re-shoot unless I can somehow fix it.

2. Is it possible to fix this so I don't have to re-shoot? I've tried AE's Color Stabilizer set to "Brightness" and that removed the pulsing but left flicker, so I'll play around with that in the meantime, but if anyone has a magic trick for fixing this pulsing I'd dearly appreciate it.

Incidentally, the lens used today was a Canon 35mm f/2.0 IS and the footage with pulsing (I've not checked all footage yet) was shot at f/6.4.

Thanks for your help with this,

Mark.

dmilligan

Quote from: markodarko on May 19, 2016, 12:18:19 AM
It's not a "flickering", it's definitely a "pulsing" phenomenon so MLVFS's deflicker feature doesn't seem to do anything with it no matter what values I put into the deflicker box.
The deflicker algorithm just equalizes exposure, so it doesn't matter if the change in exposure is slow or fast, it just tries to match the exposure of each frame to a target. Just to make sure it's actually doing something at all, put a low value in the box and verify all the images get darker. If not, perhaps either the software you are using doesn't respect the metadata field MLVFS sets to achieve the deflicker, or images have been cached and aren't getting reloaded (I should probably make it where changing a setting automatically clears MLVFS's internal image caches).

markodarko

Ah. Could it be that MLRawViewer doesn't support that metadata? Basically I was changing the deflicker number in MLVFS and opening the cDNG sequence in MLRV to see if anything changed (as this is the only place I can playback RAW files in realtime on my machine).

I can try directly in AE but I have to render each time to see it play in realtime. What value would you recommend I try with?

As an aside, does the deflicker metadata stay with the cDNG files if I copy them out of the mounted folder to my HD? I don't normally do this but the clip I shot is very long and is 21Gb. I only really need the middle 8Gb so I was going to copy out a chunk from the MLV.


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dmilligan

Quote from: markodarko on May 19, 2016, 11:57:35 AM
Could it be that MLRawViewer doesn't support that metadata?
Probably. ACR is the only thing I'm aware of currently that doesn't ignore it.

Quote from: markodarko on May 19, 2016, 11:57:35 AM
I can try directly in AE but I have to render each time to see it play in realtime. What value would you recommend I try with?
Usually around 3000-4000 is good. You can always just adjust exposure in ACR if the value you chose made it to dark or bright.

Quote from: markodarko on May 19, 2016, 11:57:35 AM
As an aside, does the deflicker metadata stay with the cDNG files if I copy them out of the mounted folder to my HD?
Yes

markodarko

Thanks for your help with that @dmilligan, I shall try that when I'm back from my walk.

Need to do some experiments to see if it was the exposure override causing the pulsing before I go out next too.


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markodarko

I can confirm that it is definitely linked to the Exposure Override function. After re-reading the old post I linked to they mentioned that they were able to see the pulsing live on the LCD screen, so I've just tried it with the same exact settings and lens as I had yesterday (Canon 35mm f/2.0 IS @ f/6.4 & f/4.5) and you can indeed see it - if you look for it - but it's not easy to see live. The best way I found to see it was to zoom in at 10x and move the joystick to a mid grey part of a scene that's not quite in focus.

I turned Exposure Override to OFF and the pulsing stopped. Yey! At least I now know.

So, as the clouds seem to be OK I'm going to re-shoot what I shot yesterday safe in the knowledge that I won't have that pulse when I return to see my footage. Whether or not the footage is any good is another matter. :-P

All the best,

Mark.