Fixing massive green shift from LED stagelights?

[Greg Janza]

You probably could make improvements on those colors through the secondary color corrector which allows you to isolate individual colors.

I Hate Television. I Hate It As Much As Peanuts. But I Can’t Stop Eating Peanuts.
– Orson Welles

[Alan Okey]

This could be easily corrected in DaVinci Resolve. Try the hue vs. hue curves.

[Boris Dimitrov]

Hi Dave and thanks for your input!

After some research, it appears that the issue is specific to some Sony cameras that have irregular sensitivity to some variations of highly saturated purple/magenta and blue light, specifically from LED stage lighting (although I have found some mentions of the issue with architectural lighting as well). In case it’s of interest to you or anyone else, here is one of the more in-depth threads I have found:
https://www.eoshd.com/comments/topic/7172-sony-a7s-color-channel-clipping-issues/

TLDR:
when filming stage events with LED stage lighting with Sony cameras, stay at 5000K WB and one of the following creative style settings – “Clear”, “Deep”, “Light”, “Black & White”, “Sepia”, or “Autumn Leaves”. This will likely result in more postproduction work to get the right colors, but will minimize the risk of getting what is pretty much unusable footage with major color shifts and clipping.

It is unclear why this issue occurs and as far as I know, Sony have not taken any action to eliminate it despite it being a known issue for quite some time now.

I could probably live with the issue if it was just the color shift, but the horrible highlight rolloffs/clippings makes much of the footage unusable, like in the frame grabs below:
https://drive.google.com/file/d/1hfinBbIB84Fv17dNEPQIoNU8rE-J_CAx/view?usp=sharing
https://drive.google.com/file/d/1a0xNTAu0V-c72sbUnVQcb4jAFhgw8Bj8/view?usp=sharing
https://drive.google.com/file/d/1lziJPzyGSZi9nuji-nZZXSKRnKNGAQmI/view?usp=sharing

Thankfully we have some other cameras which will help us save this particular project, even if not with the best possible result. But definitely something we will be extra careful about in the future – never again will we agree to film without testing camera equipment with the full range of lighting that will be used for an event!

[Boris Dimitrov]

Hi Alan and thanks for the tip!

I envy your skills if this seems like an easy fix! ☺ I am a Premiere Pro/Lumetri/Colorista user and dont have any experience with DaVinci Resolve, but I’l definitely either try and find a corresponding hue vs hue curves tool thats available in Premiere or possibly even try out DaVinci itself.

[Alan Okey]

[Boris Dimitrov] “Hi Alan and thanks for the tip!

I envy your skills if this seems like an easy fix! ☺”

Thanks, but my skills aren’t really responsible for the ease of the fix. It’s just a question of selecting the right tool for the job!

Here’s a screen shot of the hue vs. hue curve correction in Resolve, comparing your Canon still to the corrected Sony shot. It only took a few seconds to get this result, and I’m sure with some finessing, it could be even better.

https://drive.google.com/open?id=13KGTrTaBvh1csLyi0oQfRW-HXgAKKPPD

[Boris Dimitrov]

Whoaah! You should have seen the look on my face, heh.

I think I should in theory be able to get a similar result using the HSL Secondary tool in Lumetri Color, but my last attempt was.. less than stellar. Relatedly, think you might slightly be on the modest side regarding your skills/feel for how to do the right edit ☺

I’ll definitely give it another shot now that you’ve shown me its possible, if i am able to get it even close to what you have achieved, I think i’ll will have pretty much solved my problem!

Massive thanks once again for essentially shining a light in the tunnel!

[Boris Dimitrov]

Just played around with HSL Secondary some more and also read into how the hue vs hue curve works in DaVinci.

From what I am able to work out right now, the HSL Secondary is alot less versatile in selection/correction in the way it is built.
You basically make a selection in hue/sat/lum with ‘rolloffs’ on each side (is it me or is there no way to make the two ‘rolloffs’ on each side of the selection a different length?).
You then apply global corrections (by global i mean they apply to the whole selection, falling off gradually where those ‘rolloffs’ of the selection are) in hue/sat and other adjustments.

For comparison, if I understand it correctly, the hue vs hue curve in DaVinci allows you to make different adjustments to the different hues that comprise the selection with very precise control. You can, as Alan has done, shift greens alot, cyans a little less, and blues ever so slightly.

That seems to be precisely whats needed for the edit I need to do on my footage, and I can’t seem to find a way to do it with Lumetri as of right now.

I did download DaVinci, though.. it’s getting late, but ill dive right in tomorrow! 🙂

[Alan Okey]

[Boris Dimitrov] “the hue vs hue curve in DaVinci allows you to make different adjustments to the different hues that comprise the selection with very precise control. You can, as Alan has done, shift greens alot, cyans a little less, and blues ever so slightly.

That seems to be precisely whats needed for the edit I need to do on my footage, and I can’t seem to find a way to do it with Lumetri as of right now.

I did download DaVinci, though.. it’s getting late, but ill dive right in tomorrow! :)”

Resolve is a great tool to have in your tool kit, and as the free version is extremely capable, there’s no reason not to dive right in. In addition to being a world-class color application, Resolve is also a great Swiss army knife that is useful for many non color-specific tasks such as transcoding dailies, adding window burns for timecode or other data, and syncing dual system sound. Since it greatly leverages GPU processing, it can perform some tasks much faster than other applications.

Enjoy exploring Resolve!