ISO and Low Light

[JT Thurlow]

Hi there,

I'm wondering what is the recommended max ISO setting for getting clean images in low light?

On a current project I'm trying to use available light only and this is looking to be potentially problematic with certain lenses.

After shooting some full-face ECU tests (using the old Scarlet), they look good when boosted to 500 but too dark at 250. They seem to look okay on the editing monitor but not sure how they would hold up after grading/when exhibited. On my last project everything looked fine in that regard until I noticed noise in some scenes when it was shown in theaters. Hoping to get clean images with as little noise as possible.

Thanks!

 

[Michael Tiemann]

The general consensus (which you can find if you search) is to expose at ISO 320 (160 using new ISO calibration) if you want to minimize noise in low-key shots, or to expose at ISO 1600 (800 using new calibration) if you want to protect highlights in hi-key shots. The Skin-Tone/Highlight (STH) OLPF gives great colors at the cost of about 2/3 stop reduction in light hitting the sensor. The LowLight-Optimized (LLO) OLPF allows the most light to hit the sensor. If you shoot dark scenes at ISO 800 or above, you are asking for noise.

 

[James M. Holmes]

Thank you for the question and thank you for the answer. Good stuff to know.

 

[Aaron Lochert]

Scarlet Dragon or Scarlet-X?

Either way, as little noise as possible typically means shooting as low of an ISO as you're comfortable with, since that also means compromising your highlights.

I'm gonna give you the typical answer of "do your own testing," because no one can tell you the magic number as noise is quite subjective and what someone might consider clean, you might still consider too gritty, or vice versa. Your personal threshold for highlight detail might dictate this choice as well. And lastly, the existence of noise reduction software throws another possible variable into the mix.

Can you contact a theater and demo some test clips on an slow business day?