FS7: How to create a 1D (M)LUT for Slog3/SGamut.cine - to - LC709A WITH tweaked saturation

jasonbrooks

jasonbrooks

Well-known member
Hi all,

As the title suggests, I'm wondering about the best approach to creating a slightly higher-sat version of a LUT to convert Slog3 to LC709A in my Zacuto GHD (hence the 1D requirement). I've currently got an exposure corrected (Native, 1-stop-over, 2-stops-over) set of straight Slog3-LC709A LUTs loaded, having created them easily and quickly using @Cameramanben's excellent LUTcalc app, and in general they work very well.

However, I can't find any way in LUTcalc to increase the saturation of the LUTs slightly (to aid in perception of incorrect WB settings during run and gun) whilst keeping a 1D export format. I imagine there might be a way to do it in DVR, but I've never exported LUTs from there, and given their pretty critical role in the whole process of shooting, I'm reluctant to experiment!

Anyone have any smart ideas (or even dumb ones) that could help me out with this?

Thanks!

jason
 
1D LUTs cannot alter saturation. So in fact you are not getting proper LC709A output if you are sending an S-Log3/S-Gamut3.Cine signal. You will be getting LC709A gamma, but the colour space will still be S-Gamut3.Cine. That is why your image looks desaturated. If you want to change gamut and/or saturation, you need a 3D LUT.
 
Nick_Shaw said:
1D LUTs cannot alter saturation. So in fact you are not getting proper LC709A output if you are sending an S-Log3/S-Gamut3.Cine signal. You will be getting LC709A gamma, but the colour space will still be S-Gamut3.Cine. That is why your image looks desaturated. If you want to change gamut and/or saturation, you need a 3D LUT.
Click to expand...

Brilliant, thanks for the clear and concise answer Nick. I was wondering if that might be the case (didn't seem like @Cameramanben to leave such a useful feature out of LUTcalc for no reason!).

I guess I'll just have to satisfy myself with cranking up the saturation on the GHD's internal display calibration, and live with the blindingly bright green elements on the OSD! I'll also try to bring it to Zacuto's attention that they should implement 3D LUTs ASAP!

Thanks again,

jason
 
Donny 123 said:
Sorry a bit off topic.. but how do the in camera LUT,s look on the Grat HD.. thanks..
Click to expand...

Sorry Donny, not exactly sure what you mean. If you're talking about applying a LUT in-camera, and then feeding the LUTted signal to the GHD, I'm not sure, as I've had the Grat since day one, and thus never had to step into the world of pain that FS-7 internal LUTs sound like!

Sorry not to be able to shed more light on things,

jason
 
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