are natural skin tones achievable with the A7s without using LUTs?

Nicholas Natteau said:
Samuel, Michael, and pianoboy, thank you all very much as well. Will be sure to check out Kholi's cine profile. I haven't I tried that one yet. I just finished watching Philip Bloom's A7s seminar (42 min) on youtube:https://youtu.be/zeX-eZXaRtw

After 13:00, he discusses picture profiles, saying that for the CNN series "The Wonder List" he shot mostly in Cine 4 with S-Gamut (in daytime) and Cine 2 (at night), but avoiding S-Log2 in daylight (due to the 3200 ISO constraint). Will be posting my results shortly. Thanks again, everybody.
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I saw that as well and was really wondering! The cine gammas are there for quick correction with levels or lift/gamma/gain controls. S-Gamut needs color space conversion for Rec709 displays!
I'd rather use the usual suspects as a color matrix (Movie, Pro, ITU).


Samuel H said:
sgamut is highly non-linear (skin changes color depending on exposure, goes from green to magenta) and horrible according to almost everybody who has ran a controlled test
it must be used with the correct LUT-based workflow, or avoided
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Not if treated/converted properly. I also shot some tests and didn't encounter this. Was a more limited range though, from normal exposure (2 stops over, 3200 treated as 800) to 2 stops under (or "normal" S-Log2 exposure to 0).
If you want I can share the screenshots/results.


kostas said:
Personally, I find that the Sony delivers pleasing skin tones even without using PPs and LUTs.
I tend to use the flat profile with saturation set to -2, contrast to -1, and detail to -2, then use RGB curves to grade.
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Yeah that's right! Don't underestimate the PP off settings! Try STD, contrast -3, sat 0, sharpness -2. Almost a log like response and easy to grade/correct!
 
The thing about color checker cards/charts is that you will need to shoot them into each scene you shoot.
I got into them thinking it was going to be a little bit more of a "tune your camera and NLE once" kind of situation, but that's really not the case.
You also have to remember that your frames of the color charts will generally be lost to the edit if you don't color correct before you edit.

A great tool to be sure. But it does require a little bit of serious thought and consideration.
 
Nicholas Natteau said:
Thanks very much MichaelFischer for those samples. Unfortunately, I don't have a color chip chart, just a Lastolite EZbalance 18% grey on one side and white on the other. I was thinking of getting this chart here:

http://www.bhphotovideo.com/c/produ..._fbos_frontbox_oneshot_dailies_reference.html
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The DSC charts are the best choice of course, but I find them rather expensive. A full chorma du monde would be my dream, but I don't fancy putting down at least 1k for that.
I found a way to use the < 100 $/€ color checker to bring the footage to the specific color targets. It takes a bit to explain how to do this though, and I'd rather do this in article form. Have this on my TODO, but would be interesting to get some feedback if this will be useful?

DPStewart said:
The thing about color checker cards/charts is that you will need to shoot them into each scene you shoot.
I got into them thinking it was going to be a little bit more of a "tune your camera and NLE once" kind of situation, but that's really not the case.
You also have to remember that your frames of the color charts will generally be lost to the edit if you don't color correct before you edit.

A great tool to be sure. But it does require a little bit of serious thought and consideration.
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You are right, you should balance/profile your footage for each light source that you use (Sun, HMIs, Tungsten, LEDs, Fluorescents). But are you even doing this now?
If you do this once, with a more or less accurate profile, you can get rid of most of the cameras inherent look or color balance. For color critical work you definitely should shoot a color target for each new scene. For narratives it's usually not that critical and if you throw in a film print LUT at the end, most of the color correction work will be distorted again. But the base look will still shine through a little bit.
 
ReelWorksMedia said:
Yes, but I am interested in "great skin tones." Definitely possible to use a LUT in seconds and not achieve this. Just looking for an example in various situations.
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great skin tones is exactly what i was referring to. when i shoot with my rec709 lut as reference in SLOG2 with the shogun and then apply it in post, i get great skin every time. i typically always do a bit of skin-targeting in my work to smooth out blemishes a bit or whatever, but even if I didn't i think the LUTs sony provided for slog2 (which is what i based mine on) deliver very accurate and pleasing skin tones.

of course that is all assuming you had good lighting, correct WB, and the right picture profile, etc to begin with.
 
Hi Michael,

Sorry for the long delay in replying, but yes, I would very much like to know more about your method for getting great skin tones with the A7s and your use of color charts. You said in your previous reply:

"If you properly bring S-Gamut into the Rec709 color space, you will get great results IMHO. To do this I brought the S-Log2 signal to linear, applied the proper matrix and adjusted the Hues and Saturation to match the targets on the Color Checker, which you can see in the pictures and brought it back from linear to a nice gamma curve.
If you want to know in detail how I do this, let me know. I already prepared an article, but it needs some final touches...

"Did you finish that article? And if so could you share it with us? Interested to know your technique using the color chart. Thank you in advance.
 
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MichaelFischer.at said:
Okay guy's, just finished punching in the first article into my website:
http://www.michaelfischer.at/blog/85-resolve-workflow

Second one regarding color is coming soon and is building up on that! Feedback appreciated!
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Thanks for the write-up, a few notes:
Not convinced that bothering with the limited s-log precision is worth it if you consistently overexpose 2 stops. If I am gonna use a light meter and expose s-log at 800, might as well just shoot in one of the Cine gammas for the much better tonal precision with a similar highlights latitude. The plastic skin from shooting limited precision s-log is a much bigger issue than the somewhat compressed highlights in Cine curves (highlights compression is controllable through profile knee settings). And usually you are gonna compress highlights in s-log after processing anyway.

Yes, you can't linearize Cine as easy as s-log but so what? That's why one'd use a light meter in the first place - for consistent exposure in camera which mostly removes the need for significant exposure adjustments in post. Imo, the only excuse for shooting s-log is if you overexpose around 1 stop. Expose normal and noise is quite visible. Overexpose 2 stops and you lose highlights advantage over Cine curves. ~1 stop sort of makes sense.
 
If you're using LUTs, should the exposure level be at 0 in Manual Metering mode on the A7s? Just asking because I shot S-Log2 overexposing by 2 stops, according to the wolfcrow method. But when I apply any LUTs in post, the image becomes blown out and way oversaturated. Are LUTs therefore supposed to be used with the A7s MM exposure setting at 0? Thanks in advance to anyone who can clarify this for me.
 
What luts are you using? You'll have to pull them down in post unless you're using specific luts designed to be over exposed. Personally I think +1 is about right if you're going solely on the cameras meter and shooting in camera as opposed to externally.
 
Thanks for your help Casey. I have Alistair Chapman's two sets of LUTs (A7s film Luts, Slog2 to 709) and Impulz Pro's. Yes, I also discovered in my tests that overexposing by 2 stops appears to be too much. At that point I'm losing skin texture. I believe that's what Alistair Chapman argued in his A7s post here as well:

http://www.xdcam-user.com/2014/08/e...-on-the-sony-a7s-part-one-gamma-and-exposure/

So I don't think I'll push it past 1 stop from now on. Thanks again for your help.
 
Yeah he has specific luts for different exposures, so make sure you're using 0 or +1 or +2 depending on what you do, but yes I think you're right that you may not want to push past 1.
 
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