Audio settings with XLR inputs
 

I'm shooting some drama sequences with actors where their voices will be recorded on booms or radio mics connected via the XLR inputs.

Is it best to use the auto setting for the sound levels? Or should I opt for manual? If manual, what levels are desirable?

Many thanks for your help.

It is a bit difficult to ride the levels using the tiny knobs on the side of the camera, so you'd want to use an external mixer with a dedicated sound person.
I only use the level controls on the camera when I'm shooting with very limited movement, like an interview.

Agreed, I've found it almost impossible to ride the levels manually while shooting anything that is not locked down.

Short of having a sound op I use the auto settings for run & gun. Not ideal but the next best thing if you're a one-man band. If you have the time, you could sound-check and set levels before taping each scene. There is a green dot on the audio level display that you can use as a guide to avoid clipping.

Ideally levels will peak above the green dot, average around the green dot or just below it, and not hit the the top of the scale. The exception to peaking might be impulsive sounds like a door slam or gun shot. But a lot depends on the program material, and what you are truing to achieve with the sound.

Auto gain can be a big help for one-person operations, but be careful yo do not rely on it to the point of overloading the input preamps. There are several related threads here and in other forums on this over the years that you may find of interest.