Lumetri Log Noise Issue -- please help!

thefilmaddict

thefilmaddict

Veteran
I've been shooting a lot of Slog 3 footage with our Sony FS7. I edit the footage in the latest version of adobe premiere the following way:

I place the 4k footage on a timeline and tell it to match the clips settings (3840x2160 XAVC-I 24p is what I shot)
I add three way color corrector
I add ImpulZ Luts via lumetri effect
I tweak the 3 way color corrector if the image is under or over exposed

The issue I am running into is noise (small noise sometimes and bigger blocks other times).

Why is this happening? Is it a limitation of grading in premiere? Any way to get better results?

Here's the test video:

https://www.youtube.com/watch?v=93Q5iSg_JWo

It makes me afraid to shoot in slog3 (even though I love the possibilities it gives you in post).
 
I usually correct exposure before I apply luts. raising exposure in post will always reveal noise.
Is the same exposure noisy with the official Sony Slog3 luts?
It might be the Impulz luts raising portions that would be crushed down normally showing the noise. Have you tried over exposing a touch or dropping the EI down?
 
Yes I agree, always normalise an exposure first or use a LUT designed for over or underexposure.

Maybe try try the LC709TypeA LUT from Sony or export a custom LUT from Catalyst Browse rather than the impulz ones.
 
It could partially be that those Impulz luts are extra noisy. I will see if the Sony LUT helps out. I am pretty certain that the FS7 when shooting slog 3 is a lot cleaner when the image is brighter. Some of the shots that were really contrasty, I shot where I didn't let the highlights go past 95. That was a mistake. I shouldn't have protected them because it forced me to add a lot of gain in post and the highlights blew out anyway. The color corrector was before the LUT.
 
Now try going into Cat browse and export a LUT with the appropriate exposure change - just use the EI slider, then export to your LUT folder, then import that LUT in Premiere when you apply Lumetri. It works, trust me:-)
 
Liam Hall said:
Now try going into Cat browse and export a LUT with the appropriate exposure change - just use the EI slider, then export to your LUT folder, then import that LUT in Premiere when you apply Lumetri. It works, trust me:-)
Click to expand...

Can you go into more detail? I've never done this before. Eager to try.
 
Did you shoot this these clips CineEI or Custom?

Catalyst Browse reads the meta data and adjusts exposure to how you rated the camera. I personally export a lut to correct exposure in other applications that don't read the EI meta data like PP/Avid/Resolve.
 
Just export the a LUT with the settings you like in Cat Browse, then you can apply that LUT in Prem Pro via the Lumetri plug-in as you would any other LUT. Then, it will be much faster. I've made a bunch of LUTS with over and under exposure plus boosting saturation. Works really well.
 
I use Cat Browse to offload clips so for me it takes no time to export a quick exposure lut for the proper EI value and use it in the programs that don't read the meta data so at least you get properly exposed footage to cut.

Allister Chapman has some over/under luts for EI values and choice. I think they are over on his site.
 
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