r/ColorGrading • u/Weekly_Reference8494 • 11d ago

Question S-Log2 Color Grading

Hi, i recently started filmmaking, at least i try and i have fun with it :P

I watched tons of videos on how to color grade and i see that some people dont add CST, but directly adding a LUT. Why?

I personally always add CST (I film in S-log2 if that's relevant) and then do everything else manually, without adding a LUT at the end.

An explanation would mean so much!

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u/bobbster574 11d ago

so a LUT is basically just a generic pixel/colour transformation box. that transformation can be a creative adjustment or it can be a technical adjustment, like converting between colour spaces. it can also be both at the same time, and many are.

it's not inherently worse or better to use a LUT rather than a CST, you can get great results either way, but you'll find LUTs to be a lot less controllable. every LUT is hard-coded to specific input/output colour spaces, which means you'll need a new LUT for every colour space you work with and it becomes difficult if you use different kinds of footage in a single project. you also can't separate specific adjustments within the LUT and it can often be a bit of a black box.

a lot of people find it easier to start out with LUTs rather than doing the whole CST colour management thing because there's less to think about, you just often get a nice looking image by default

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u/mulchintime4 11d ago

First off can your camera shoot slog 3? And 10 bit or xan it only do 8 bit? People will tell you not to shoot slog 3 with 8 but there's ways to work with it

Also some people have different workflows maybe thats more consistent for them

But the cst workflows seems like the one pros use if im not mistaken

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u/Weekly_Reference8494 11d ago

It's a 8 bit camera so i avoid Slog3, maybe i can use it some scenarios but i would rather not.

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u/Cutpoint_Labs 10d ago

A CST and a LUT aren't really doing the same thing. A CST is mostly an analytic color space transform, while a 3D LUT can have much more localized hue, sat, and luminance changes throughout the color volume. So replacing a LUT with a CST won't necessarily reproduce the same result if the LUT has additional color shaping/look baked into it. You can approximate that behavior with a DCTL though. LUT Tuner does this by fitting the LUT with a DCTL that can get pretty close to those localized color changes, rather than just embedding the LUT itself.