new Slog gamma profiles

[Leonard Levy]

Now that we have sLog as a profile option I'm wondering if there are any suggestions for settings.
On first thought it seems to me that being able to color balance and use Kelvin presets is very valuable especially for on set monitoring, but most of the settings for black, black gain, knee, & gamma levels (is that even there now) are pretty pointless in Slog. What about detail and matrix settings which are now default - off?

I usually have my detail level around -17 and frequency and aperture up around 20 more or less as suggested by Alistair Chapman. Any reason not to use those settings for Slog as well?

Likewise most of us have matrix settings we liked in the normal and cine gammas. Is there any reason to keep matrix off in Slog? Alistair told me at NAB that saturation was kept low in Slog to avoid chroma clipping. Does that mean it needs to stay off altogether?

[Alister Chapman]

You can mix and match whatever you want in the picture profiles, but the question is... what are you trying to achieve?

S-Log is designed to capture the greatest possible dynamic range from the sensor in a way that gives the optimum flexibility in post. If you start boosting the saturation or adding back in detail correction you reduce your post production options as once added they are difficult to take back away again.

You can use the S-log gamma curve to make up a picture profile that has good contrast by using lots of negative black gamma, but I don't like the way skin tones are handled when doing this, as with conventional exposure levels faces etc end well up the curve in the more compressed region. IMHO S-Log is what it is and is best kept for what it was designed for. The cinegammas give a very good compromise between dynamic range and a good direct to air look.

I spent some time with a colourist last week on DaVinci Resolve and when used correctly, it is quite incredible what you can do with S-Log. One of the key things with a proper grading tool over grading in an NLE is the use of Log gain. If you adjust the signal levels using most NLE software the levels are adjusted evenly across the entire image, this can result in highlights blowing out as you bring up the mid range etc quite quickly. When you use a proper grading suite working in log mode the gain is applied differently, in sympathy with the log curve and the difference is quite striking. You can pull a lot more out of the image as a result. There is a lot more to learn about grading and working with log in post! When we tried some experimental profiles based on S-Log the colourist had a really hard time working with them as they no longer conformed to the standard log curve and were not like a conventional gamma either.

[Douglas Villalba]

Hello Alister,

So in your opinion the best way to start using Slog is to use one of the PP setting, reset it and then just add S log to the gamma settings?

[Leonard Levy]

Alistair,
Unfortunately I'm still grading in Final Cut and my old computer can't use Resolve. Is "Log Gain" a specific feature of Resolve and other higher end Correction software?

What I've been trying to do in FCP is use a combination of LUT Buddy using a curve from you, Abel Cine or Arri and coupling it with the 3 way to get the exposure centered where it belongs on the S curve (using the gamma adjustment) and adding a shadow-highlight filter to compress and keep the highlights. So far that tends to look pretty good but I hear what your saying about the gamma setting in the 3 way raising the highlights as well. I'm trying to compensate with the shadow highlight filter but it would be better to have something like log gain. Don't know if that can be accomplished in FC P though. Does Color have "Log gain"?

Also what do you think about detail settings in Slog? Any reason not to set them where you like instead of off. I find post sharpness settings kind of confusing and feel safer setting them in the camera.

[Douglas Villalba]

To really get those 7 - 13.5 stops within the standard specs you need a program that can work on a particular range without going into another too mush.

I know that color is good for it, but I haven't used it enough to tell you how to do it with it.

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