ISO for two different scenes that will be intercut

[Nicolas POISSON]

Hi,

I am joining a short movie project with no budget and relying on hobbyists. A rather bright scene has already been shot with a Sony FX6 in Cine EI mode (Slog3). The team used mainly natural light. It was shot at 800 ISO, then they switched to 12800 + some ND at the end of the day when light started to miss.

I am to work on a bar scene, which will be inter-cut with the first already shot scene, although they are totally different visually. The bar will have a moody reddish atmosphere, and I expect most of the objects to fall in the lower IREs. The camera will be a Sony A7sIII in Slog3. We bring additional lighting on location but not that much. Given that the A7 is supposed to have the same sensor as the FX6 but has analogue gain, what would be the best strategy concerning ISO?

- stick to the native ISOs as in the first scene (640 or 12800 on the A7) ?

- or set the ISO to expose the bar scene properly?

My understanding is that the consistency in noise and dynamic range is already killed by the use of two different native ISOs for the first scene. I would choose one ISO for the bar scene that gives me enough exposure, not taking into account what was used before. Is this correct ?

Edited November 11, 2023 by Nicolas POISSON