Exposing Slog3 during night time and/or low light scenes

[anthony eynard]

Hey everyone. I apologize if this is an elementary question, but it's something I've been wrestling with for some time. There's a ton of info out there on exposing S-Log 3 based on a few tools, including: ETTR, the controversial expose to 1.7 using multi meter, using zebras set to 55+/- for skin tones or 94+/- to avoid blowing out highlights, and using false colors or middle grey card to ensure skin tones are exposed properly. 

I get all of this when shooting in daylight or well lit scenes (I for one rely on zebras or false color), but I can't wrap my head around how you would "properly" expose a scene using these methods, with or without a human subject in lowlight or night scenes. i.e living room scene at night, with subject lit only by a lamp and the distant glow of a television, or on the street at night with subject or scene lit only by street light, nearby signage etc. 

Following the standard rules/tools above, exposing the skin tones or even a middle gray card in these settings with zebras set to 55 +/- for examples would expose the rest of the scene in a way that is to bright and inaccurate..?

Then, for night time/low lit scenes without a human subject, how do properly expose these with S-Log 3? I sometimes use zebras at 94+ and aim to not blow out the light source (such as the lamp, or street lights from the examples above) But is this accurate?

Maybe I'm overcomplicating this because I'm not seeing a ton of info on it, but I would love a good breakdown of how to expose in these scenarios. Thanks in advance!

[Adrian Sierkowski]

A lot of this depends on the camera. Some SLOG3 cameras are 8 bit and generally pretty not great to work with in SLOG. But, if you are over-exposing everything; then you just over-expose your night scene too-- which means you have to light it. The idea being you'd then bring down the entire scene later on (thus crushing the noise down) and getting an "appropriate" night exposure. If you aren't lighting then perhaps SLOG is the wrong choice for night shooting-- but you will need to actually test this for your situation.

Personally, I don't care if a light bulb blows out, especially at night. But in the case of a "character lit only by a lamp" i would re-globe the lamp down low (11 or 25w or an NYX) and then mimic the lamp light with a different unit (like a litemat 4) coming form a similar direction as the lamp. Same with a TV. This depends on the shot you're doing though; but often this stuff will be hidden just off frame.

I just recently shot SLOG 3 on an Fs7MKii, which I haven't used in ages. We had some night scenes, and some of these situations as well. I will say I never exposed to the right (on any camera really.. outside of 500T film) and I just looked at the scene via a SLOG3 to REC Lut on my monitor and judged exposure based on that. Occasionally I'd toggle over to LOG to see what the camera sees, and look at the waveform on the camera, keeping the image from crushing the blacks too much. Putting the footage into resolve later on to make some proxies for the director, i didn't notice any real noise. But SLOG in an FS7 is "meatier" than SLOG you'd get in an A7s for example (which is 8bit if memory serves)

 

Also highly recommend using false colors when you can. Personally I like the use them from the camera (some prefer to use it on their monitor but I don't trust camera live outputs fidelity). It really is an extremely useful exposure tool especially for digital.