GH4 V-LOG L noise reduction and color accuracy

Shian Storm said:
it's your grading procedure. V-log needs to be interpreted properly or you will introduce this artifacting. The Varicam LUT does not do a very good job, neither do any of the BMD LUTs, Cineon is too dense. Try "S-log to linear" and correct for the greencast, and then match there's a good chance you won't see this. Or wait for me to release my custom conversion LUTs, but I'm not having this problem at all, unless I try to grade by hand or use the other LUTs
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Nice, where can I find this "S-log to linear" LUT?
 
Batutta said:
I have not. Only Cine D with contrast dialled down to -5 and master pedestal +15. It has everything to do with V-log in 8-bit.
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Same issue. The more you have to push the image in post, the more you exaggerate this issue. What you are seeing are subtle MPEG encoding errors. You can even make the same green/magenta errors without your camera. Make a grey scale image, export it through an H264 encoder and then push the resultant file in your NLE of choice.
 
joe12south said:
Same issue. The more you have to push the image in post, the more you exaggerate this issue. What you are seeing are subtle MPEG encoding errors. You can even make the same green/magenta errors without your camera. Make a grey scale image, export it through an H264 encoder and then push the resultant file in your NLE of choice.
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So the issue is not present when using prores?
 
Shian Storm said:
it's your grading procedure. V-log needs to be interpreted properly or you will introduce this artifacting. The Varicam LUT does not do a very good job, neither do any of the BMD LUTs, Cineon is too dense. Try "S-log to linear" and correct for the greencast, and then match there's a good chance you won't see this. Or wait for me to release my custom conversion LUTs, but I'm not having this problem at all, unless I try to grade by hand or use the other LUTs
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The artifacts are encoded into the image, but yeah, different grades minimize or maximize how noticeable they are. I definitely think there is room for improvement over the standard V-LOG to 709 LUT. I was pretty easily able to do a better job than that LUT.

Please post back here when you have a custom LUT, would love to try it.
 
David Del Real said:
I have Resolve 12 and found SLog2 to Linear, is that what you mean? Yeah, I only work in Resolve now for coloring/grading.
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Yup. Will create a green cast. Doesn't place everything exactly where it;s supposed to go as accurately as SOLID, but it's a better starting point than the other LUTs
 
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Shian Storm said:
it's your grading procedure. V-log needs to be interpreted properly or you will introduce this artifacting. The Varicam LUT does not do a very good job, neither do any of the BMD LUTs, Cineon is too dense. Try "S-log to linear" and correct for the greencast, and then match there's a good chance you won't see this. Or wait for me to release my custom conversion LUTs, but I'm not having this problem at all, unless I try to grade by hand or use the other LUTs
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I was actually starting to think it might be the LUT, although no other LUT I threw at it yet has seemed to fix it.
 
Batutta said:
I was actually starting to think it might be the LUT, although no other LUT I threw at it yet has seemed to fix it.
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I have James Miller's V-Log LUTs and there are a few in there that suppress this well. Off hand, AA20 I remember looking good.
 
Zak Forsman said:
I have James Miller's V-Log LUTs and there are a few in there that suppress this well. Off hand, AA20 I remember looking good.
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Well I'll be a son of a *****! Still can detect it slightly but much better with Miller's LUT. Definitely usable. I'm using AA709A Native General. Thanks Zak...and thanks Shian for educating us 'idiots at dvxuser'. And quit using that varicam LUT people.
by3a.jpg
 
Wait a minute! I think I discovered something by accident. Zak recommended Miller's LUT AA20. I had an LUT on my system called AA709A Native General which I thought was Miller's. Turns out, I had downloaded it from Art Adams website. He made an LUT for Sony F cameras to match to Alexas that happens to be an almost perfect match for V-log. And it's free. Download link at the bottom of this page--

http://www.provideocoalition.com/lutcalc-trials-and-errors-plus-a-free-lut
 
in Art's description of the AA709A LUT: "This is a combination of Sony’s LC709A gamut and Panasonic’s V709 gamma curve."
 
Shian Storm said:
The S-log LUT comes standard in Davinci Resolve. If you are not grading in a 32 bit space, then God have mercy on your soul... and your footage.

https://www.flickr.com/photos/76276262@N04/albums/72157658753193921

http://www.personal-view.com/talks/discussion/comment/205908#Comment_205908
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What other NLE's allow us to edit in a 32 space? I know AE can be switched to it, but I don't know way FCPX runs in or if it can be changed. Or better yet, if you have an efficient workflow for going from FCPX to Davinci Resolve, that would be awesome.. Thanks in advance!
 
Frantikthegod said:
What other NLE's allow us to edit in a 32 space? I know AE can be switched to it, but I don't know way FCPX runs in or if it can be changed. Or better yet, if you have an efficient workflow for going from FCPX to Davinci Resolve, that would be awesome.. Thanks in advance!
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FCP X to Resolve is the easiest thing in the world. Export fcpxml, import into Resolve, grade, and export from Resolve. Also FCP-X is 32bit. But, without the Log conversion you're playing with fire. Maybe someday Apple will get their s*%t together, and have these options in the base package and not need a 3rd party LUT Utility
 
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Batutta said:
Wait a minute! I think I discovered something by accident. Zak recommended Miller's LUT AA20. I had an LUT on my system called AA709A Native General which I thought was Miller's. Turns out, I had downloaded it from Art Adams website. He made an LUT for Sony F cameras to match to Alexas that happens to be an almost perfect match for V-log. And it's free. Download link at the bottom of this page--

http://www.provideocoalition.com/lutcalc-trials-and-errors-plus-a-free-lut
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That LUT is the money for sure!!!
 
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