• 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

Clarity and Contrast Problems causing Flicker in LR

Offline
#1 sketch2099
Apologies if this has already been discussed.

I've been doing  long exposure, night time lapses for several months now, and keep running into a problem with flicker.  A problem that no amount of deflickering can solve.

This is because I keep seeing frames that are exposed identically next to each other in a sequence with varying brightness in the center of the image versus the perimeter.  

Because of these frames, I would often run into great difficulties in the deflickering process.  Two frames can have the same Visual Luminance value, even though the edge and center luminance values vary.  Shifting the reference area does not help, as the deflickering process tries to correct for a level of brightness in one part of the frame, it makes other areas of the frame flicker instead.

I do not use the Dehaze slider, as it's an adaptive process that can apply different effects to different areas of a picture, relative to the next picture in a sequence that may be panned a fraction of a degree.

This got me thinking that I must be running into this problem with one or more of the sliders.  

Turns out, after much experimentation, both the Contrast and Clarity sliders work the same way.  A frame is analyzed and adjusted based on that frame only.  These sliders can have drastically different results on two different pictures in a sequence that appear to be identical in every way.  They may create a vignette or hotspot on one, and not alter the next photo at all! 

As much as I love using these sliders for stills, I will now only do so with great hesitation, and will have to check for any flickering problems they may cause in future night timelapses.

Thought this might be of interest to others.

Frame 1 of 2 with Contrast and Clarity Sliders Utilized
   

Frame 2 of 2 with Contrast and Clarity Sliders Utilized (Hotspot in middle of frame) 
   

Frame 1 of 2 without Contrast and Clarity Sliders
   

Frame 2 of 2 without Contrast and Clarity Sliders (No varying level of brightness in different areas of frame)
   


...now to the next issue, how to get rid of all the damn purple from the A7S
Offline
#2 Gunther
Yes, unfortunately in those cases the Camera Raw algorithms can really be a pita.
The only option then is to use a rather "flat" editing in LR/LRT, deflicker as good as it gets, then render as ProRes and do some more color grading and contrast editing in video editing.
Subscribe to: LRTimelapse Newsletter, Youtube Channel, Instagram, Facebook.
Offline
#3 sketch2099
Thanks for the input Gunther.

That's exactly what I ended up doing.  

I just exported 16-bit Tiffs instead of my usual 8 bit jpeg method so I could get the full 10bit usage out of Prores files when doing further contrast adjustments to the video file.

Too bad there's no clarity slider in Premier Pro's color correction tool.  I have to take the files into Davinci Resolve and use it's "midtone detail" if I want to get some of that clarity pop back into the video.

...also check out: