Preventing Color/Luma Shifting When Processing DNGs in Adobe Camera RAW

Started by evoxio, May 26, 2013, 07:34:17 AM

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Fauxto

It's a problem for me as well. I've seen it happen big with a shot of kids playing with water under full sun.

I'm using Camera Raw 6.7 in AE CS.5.5. If I don't use recovery or fill light it doesn't happen at all.

I was planning on shooting a short film in a couple of weeks but now I'm having second thoughts.

senzazn12


hjfilmspeed

I have seen it too. From what ive seen it seems real subtle. Kind reminds me of film and how it would flicker a little.

jmanord

I have been trying to find ways to avoid the flicker as well. I haven't done extensive testing, but I'm wondering if the cause is more related to the same flicker that occurs in time lapse video from the aperture blades not closing, or staying closed, to the exact same diameter. I shot several videos today with a Rokinon lens and haven't noticed any flicker among the videos I've processed so far. Since the aperture blades are controlled manually, it should alleviate the problem. I am going to test with my autofocus lenses tomorrow by shooting them stopped down and wide open to see if this has any effect.

s---70

It doesn't have anything to do with the aperture blades. when taking photos they move into the right diameter for every frame and it does that with slight variations. during livewiev the aperture is obviously locked so that can't be the problem. We already know the why it flickers, it's just the algorithm of camera raw that was not designed to be used with video. Just don't use ACR highlight or shadow recovery and contrast in the 2012 process in the shots where the flickering occurs.

senzazn12

Quote from: s---70 on July 05, 2013, 05:22:29 PM
It doesn't have anything to do with the aperture blades. when taking photos they move into the right diameter for every frame and it does that with slight variations. during livewiev the aperture is obviously locked so that can't be the problem. We already know the why it flickers, it's just the algorithm of camera raw that was not designed to be used with video. Just don't use ACR highlight or shadow recovery and contrast in the 2012 process in the shots where the flickering occurs.

I am using process 2010 in AE ACR 6.7 and the same flickering happens when using fill light and recovery.  Is there a workflow other than Cineform, Ginger HDR or Resolve that can process these files withoug flicker?

1%


senzazn12

Quote from: 1% on July 05, 2013, 07:05:10 PM
Don't use those features and it won't flicker.

I see. But then how are we suppose to take advantage of the dynamic range if we can't use those features?

s---70

you can reover highlights by lowering exposure and then adjust curves to get the brightness back

senzazn12

Quote from: s---70 on July 06, 2013, 01:15:25 AM
you can reover highlights by lowering exposure and then adjust curves to get the brightness back

Thanks s---70. You are right. I forgot about doing it that way. I've been tackling this with such a one dimensional mind set using fill light and shadows sliders that I forgot about playing with curves. :D

squig


senzazn12

Quote from: squig on July 06, 2013, 05:56:38 AM
Exposure adjustments cause the flicker too.  :'(

I just tested using the curves to bring back highlights and shadows and while it does not flicker as bad, the only thing is that bringing back the highlights and shadows using the curves is a little bit inferior compared to using the sliders. Man, any more enlightenment on this issue would be helpful.

iunknown

Why not take it into resolve, an app that was designed for motion?

1%

Maybe need a list of what process and what ACR features cause the flicker. I.e. will auto WB do it? etc

squig

WB is ok, chroma controls appear to be ok. Contrast is ok too. Shadow and black level sliders are ok.

senzazn12

Quote from: squig on July 07, 2013, 05:22:56 AM
WB is ok, chroma controls appear to be ok. Contrast is ok too. Shadow and black level sliders are ok.

I can confirm with Squig. It seems like fill light, highlight recovery and recovery do cause the flicker. So far adjusting through curves is okay. However, you can't recover much through the curves method alone. It sucks that the exposure slider does cause the flicker as well. I was thinking we can try to save the highlights as much as we can through curves in ACR and then adjust the exposure in our NLE after exporting from After Effects or just nail our exposure in the ball park when filming. Any more suggestions? Even though we can't recover much to avoid the flickering, we still get the added benefit of increased resolution and finer noise I guess. It would be sweet if ACR can fix the issue with the flickering though. I can't use Resolve cause my GPU is not good enough. Maybe I will be upgrade it soon. However, I heard even the demosaic processing and highlight recovery in Resolve isn't nearly as good as ACR.

mikepa

Saw this in the RAWMagic thread. Looks like it could be a solution, if it could be implemented in one of the raw converter tools

"I have a suggestion, which may or may not be a good idea!

It concerns a possible fix for putting the CDNG's through ACR, which sometimes causes exposure variances, even with using Process 2010 in ACR. It seems that ACR needs the lightest and darkest points in the frame to be constant, otherwise any highlight or shadow recovery causes the exposure shifts.

If RawMagic could add another 2 lines to the image, say a pure white one at the top and a pure black one at the bottom, this would fool ACR into treating the high and low point of all the frames as the same (because they would be the same!)"

squig


Danne

Quote from: mikepa on July 08, 2013, 11:08:33 AM
Saw this in the RAWMagic thread. Looks like it could be a solution, if it could be implemented in one of the raw converter tools

"I have a suggestion, which may or may not be a good idea!

It concerns a possible fix for putting the CDNG's through ACR, which sometimes causes exposure variances, even with using Process 2010 in ACR. It seems that ACR needs the lightest and darkest points in the frame to be constant, otherwise any highlight or shadow recovery causes the exposure shifts.

If RawMagic could add another 2 lines to the image, say a pure white one at the top and a pure black one at the bottom, this would fool ACR into treating the high and low point of all the frames as the same (because they would be the same!)"

Could you do some testing on this? Do a short batch with light and dark points as suggested and compare with the regular acr workflow?

mvejerslev

I have no good footage displaying this flickering so far. But for those that do: Does it make a difference if you are careful not to clip either end of the histogram?

Also, I've created an entry at the Photoshop feature request site here: http://feedback.photoshop.com/photoshop_family/topics/camera_raw_flickering_and_raw_video_magic_lantern?rfm=1 - feel free to contribute.
5D Mark II, PC

iunknown

Here are my test.  This was shot in manual modes with no auto settings or ettr settings on.  The exposure shift is happening without any shadow/highlight or any post effects applied.  Rawanizer is causing the exposure shifts.

-If I export using raw2cdng, it does not cause the exposure shifts.  But aliasing is more prevalant than Alex's updated raw2dng.  And I suck at bringing back highlights using the qualifier controls in resolve to bring back highlights compared to lightroom/acr.

-Exporting using latest raw2dng and creating a DNxHD in rawanizer causes exposure shifts, image looks great otherwise.

-If I bring in those same dng's into after effects and export, it looks fine.

First clip is video file out of rawanizer, second is out of after effects cs6.




I guess if you want to apply heavy shadow/highlight effects use AE CS6, or render out to prores 444 and apply the effects to the exported file.

senzazn12

Does turning on exposure override, fps override or gradual exposure affect the luma shift too? Just wondering.

romeus

Did anyone test the DxO Smart lighting option ? it's like a shadow recovery

squig

Quote from: senzazn12 on July 09, 2013, 07:03:46 PM
Does turning on exposure override, fps override or gradual exposure affect the luma shift too? Just wondering.

It's a post issue.

Faringam