Consensus on Sony A7SII Picture Profiles

Viscount Omega said:
I'm finding that too. I did a test a while ago where I shot in Rec. 709 color with s-log2 gamma, thinking I could skip the Rec. 709 conversion LUT, but it turns out the blue (and sometimes the red) channels can be blown out--even with the saturation set at zero. I don't see this problem yet with sgamut3.cine.

It's an extra step to add the Rec. 709 LUT, and it degrades the footage slightly but so far it's better.
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+1

I'm not a colourist, but Slog2/sgamut3.cine with film convert seems to work well on the A7sII.
 
Log images are supposed to be converted to other colours spaces via a technical LUT. Hand-grading from log and trying to guess by eye where something should be is a fool's errand.
 
Ben Scott said:
Log images are supposed to be converted to other colours spaces via a technical LUT. Hand-grading from log and trying to guess by eye where something should be is a fool's errand.
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I disagree - not with SGamut3.cine, as the main color dimensions are in line with REC709, they just capture a higher range than REC709. And this is exactly why I am not in favor of LUT's, as they typically degrade the image (depending on the accuracy level they provide) - every LUT is re-interpolating your scarse 8bit data. And you do certainly not want to have another step degrading your 8bit image. I have a couple of examples up on vimeo which I shot in SLOG2 using SGamut3.cine, graded in Resolve just using "hand grading by eye". Have a look here https://vimeo.com/170264332 or here https://vimeo.com/165249547 - I did not come across serious (if any) banding yet.
 
I'm not saying you cannot get decent results. I'm saying that's what log is meant for. It's not my opinion. That's a simple fact.

Now if you're doing a nice one-off project certainly you can choose to work that way, and your video looks great by the way. But signal level value A in log being converted to signal level X in REC709 or REC2020 is not something you can 'rough in by eye' with any degree of accuracy and repeatability.

And what happens when down the line you want to release your video in HDR/REC2020/wide Gamut/whatever the new standard is?

Do do you just grade it from scratch again with info on the new values?

with an output lut you can keep the underlying grade the same and change the lut for the destination colourspace.

And how is a 'manual transform' any less destructive?
 
@BenScott, of course, if your destination is not REC709 then a LUT comes in handy. I am just saying that for REC709 you do not need a LUT, and a LUT by nature is always destructive - not what you want with a fragile 8bit image. Have a look at Paul Curtis latest blog, very enlightening: The truth about LUTs http://blog.inventome.com/Blog/2016/...uth-about-LUTs
 
There is a big difference between a technical colourspace conversion LUT designed and released by the manufacturer of the camera and a 'look' LUT.
 
The problem I'm having is which s-log2 to Rec. 709 LUT to use--they all produce different results. I have 4-5 of them. Of those, I like one from some company called "ground control" but that one requires me to boost the shadows a ridiculous amount--so much it's very destructive.

I downloaded Sony's free Catalyst Browse software and tried transcoding to Rec. 709 with that. I had such high hopes--same company as my camera and my Vegas software and all. Saw the results. Will probably uninstall the software now.

Still looking for more S-log2 to Rec. 709 conversion LUT's.
 
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Well again, anything that isn't the Sony-released technical colourspace conversion LUT is possibly inserting its own 'flavour' to proceedings and is more often than not a variation of a 'look LUT' instead of a technical one.

If you expose to the published spec, or expose to the right (ie 90% at 75IRE instead of 61IRE) and compensate you will get solid repeatable results.

Using Look LUTs is a very different proposition and is the equivalent of using a Red Giant Magic Bullet preset on your footage i.e. more often than not a horrible and destructive decision, although in a pinch for super fast turnarounds capable of pulling the odd success out of the bag.
 
Hi, thanks for the explanation. Can you provide a link to the "Sony-released technical colourspace conversion LUT"? The Sony s-log2 to Rec 709 LUT for the A7s cameras?
 
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Sadly a quick look on Vimeo or YT will tell you that a lot people more posting videos have no idea what constitutes good or bad in this context than do.
 
S-Log is Slog, whether your S-log shooting camera of choices fills the container half way up or 90% up. You don't need an A7 specific one. Although with the mk1 there is scope to have a LUT dial out the slight green cast that isn't present in the mk2. This is something you could do with the original LUT and LUTCalc I guess.

If you can't find them here's the slog 2/sgamut and slog3/sgamut3.cine LUTs I have on dropbox. https://www.dropbox.com/s/jtvlmxr0s84k8z6/Sony S-LogLUTS.zip?dl=0
 
Ben Scott said:
S-Log is Slog, whether your S-log shooting camera of choices fills the container half way up or 90% up. You don't need an A7 specific one. Although with the mk1 there is scope to have a LUT dial out the slight green cast that isn't present in the mk2. This is something you could do with the original LUT and LUTCalc I guess.

If you can't find them here's the slog 2/sgamut and slog3/sgamut3.cine LUTs I have on dropbox. https://www.dropbox.com/s/jtvlmxr0s84k8z6/Sony S-LogLUTS.zip?dl=0
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It was very kind of you to post these.
Couple of questions if you don't mind:

1. What was the source of these LUTs (Sony, another website, LUTCalc)?
2. Do you use these LUTs with the A7S Mk1 -- or A7S Mk2?
3. Do you happen to have a SLog2/SGamut3.cine LUT (as this is a combination that seems commonly used by A7S Mk2 owners).

Thanks
 
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1) Sony
2) Used them with MK1 and now use with Mk2
3) No. Sorry. Very easy to make one from these in LUTCALC though
 
Because they are on my hard drive and have been for a couple of years and I can't be bothered to do your work for you. Simple.
 
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