Shooting an Event in Low Light with Multiple Cameras

[Chris Barker]

Hello,

I need to shoot an event that will be in fairly low light with multiple cameras and am concerned about getting clean footage that matches the scene, and with the rest of the film.

I am thinking of using a fast prime for the A camera (Canon 24mm or 35mm f1.4 L II), and the B camera pretty much has to be a telephoto zoom. I am concerned that using what I have, the Canon f2.8 70-200mm II, will be too slow in comparison with the faster lens. If the exposure for the event on the day should be f1.8 at 250 ISO (using a RED Gemini and I like to go as clean as possible), I suppose it would be best to shoot both cameras at f2.8, 500(ish) ISO to match the amount of noise?

The only faster telephoto zoom I could find is a ANGENIEUX EZ1 30-90mm T2.0, but I'm concerned that it's not long enough, and that using a different brand will create another mismatch. Even if the A cam was one too, I will still be cutting with elements from the rest of the film, which will all be shot with Canon L lenses (outside of a few speciality shots perhaps).

Another issue is getting some shots at 60fps with the slower lens, which will exacerbate the low light issue.

Any thoughts on navigating this situation would be greatly appreciated.

[Nathan Walters]

I'm sure someone can chime in who is more technically savvy than me.  But my thought is this.

Shooting on a RED Gemini, a sensor with dual native ISO, and limiting it to 250 ISO seems like an unnecessary hindrance.  Wouldn't shooting at its native ISO of 800 or 3200 actually give it the cleanest images and optimal dynamic range?  I would do some low light tests at higher ISOs and re-evaluate that decision.

[David Mullen ASC]

The more you overexpose, the lower the ISO, the cleaner the image gets -- but then you start limiting dynamic range and headroom latitude. When a manufacturer recommends an ISO like 800, that's because it is considered an optimal compromise between noise, dynamic range, and distribution of information between shadows and highlights.

[Chris Barker]

Thanks very much for the responses.

I have done a number of ISO tests on the Gemini and generally find that 250 is extremely clean, noise becomes more noticable at around 500 and at 800+ it becomes bothersome to me. Perhaps I am looking too hard for it though.

On a RED Tech video there was some advice saying if you want a clean look and you don't need much highlight protection you may want to shoot at a low ISO, like 400.

I rarely need to protect highlights as I tend to shoot interiors with available light and exteriors around dawn and dusk. So, my strategy for this project was to keep the ISO as low as possible (usually keeping at 250 unless the light is very low/boosting a bit to avoid straying from a lens' sweet spot where possible). I'm not sure if that's tenable or if I'm going low to the extreme or overlooking anything.

I'm also concerned that if I boost to say 800 for certain scenes these might stand out, ditto with using a Angeniuex PL lens for our Steadicam scenes when the bulk of the film will be shot on Canon L EF lenses.

Edited October 19, 2023 by Chris Barker

[David Mullen ASC]

You can't have everything, so find an ISO that works for all your lenses and light levels, or increase the light level or don't use the slower zoom. 

The only variation I can think of is to boost the ISO of the camera with the zoom by 1/3-stop and increase the shutter angle by 1/3-stop for an effective 2/3-stop increase, the difference in noise and motion blur should be undetectable.