Auto brightness?

Hello lucky owners of the new Epix! I would like to ask if the brightness of the always on display is regulated automatically based on the ambient light intensity.

Like .. evening in a dark room it is darker then during a day.

If not .. how do you deal with that?

Also .. if you have some simple, mostly black, watchface, do you get longer battery life? By how much?

Thank you!

Best,

M