FS7: Slog3 yellow color error

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Niekbraam

Member
When shooting Slog3, XAVC-I, 3840x2160 25p cine-EI, yellow really stands out in the gamma. When grading or de-saturating, it even shows something like dead pixels or very noisy area's. Just look at the yellow objects in the background in the full image.
I'm grading with Davinci Resolve. Is this common?

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You haven't provided enough information.

What is your S-gamut choice when shooting? There are two options on the camera.

How are you grading it in Resolve? There are probably a dozen different ways to grade S-LOG in Resolve.

How are you exposing? It all looks overexposed to me, but hard to sa for sure from these frames.
 
Hi Doug,

I shoot in S-gamut3. The grading is not significant when looking at the raw footage. You can see the yellow color really sticking out. Because S-log3 loves light, I always shoot 1 stop overexposed. Like explained by Alister Chapman
 
SGamut3 requires more post production than SGamut3.cine.

If you're delivering to rec709 there doesn't seem much point using anything other than sgamut3.cine not to mention shooting internally with XAVC you'll soon find you hit a barrier with the compression posterisation so you can't do a massive amount of grading before the image falls apart like those noisy areas.

You might also consider burning a LUT.
 
I’m unclear what your issue is. Where is the color error? Yes, the yellow is quite bright in the shots you showed us, but that’s because it was bright in the original scene. And the problem is…?
 
Ha eens kijken hoeveel mensen dit kunnen lezen!
Volgens mij zie ik daar een heel gele portaalkraan in de achtergrond niet veel mis mee.
Ik gebruik slog3cine werkt inderdaad net effe wat makkelijker.
 
It looks like a post problem, perhaps your primaries aren't correct in resolve - you're grading in a smaller colorspace than the SGamut is giving you, therefore any saturated colours in SGamut will be even more saturated and possibly clipped.

You'll need a suitable transform from SGamut into Rec709 somewhere in your grade.

cheers
Paul
 
Yes, I believe you are correct. That's why I asked how he had graded/handled/processed it in Resolve but we didn't get a specific answer. Hard to help if someone doesn't say specifically what they did to the footage, step-by-step if necessary. BTW, no real answer on how it was exposed either. Information such as "I always shoot 1 stop overexposed" is not helpful when trying to track down a problem. How was the exposure determined on these shots?
 
I've seen something similar, but much more drastic - orange/red LED lights behaving the same way the A7s burns out some blue LED lights.

The bright yellows could potentially be something in post
-> Do you see it that way when you are shooting it? While viewing a LUT? Burning in a LUT? etc
 
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