Important disclaimer: what I'm presenting here is my understanding of the matter - it may be extremely simplified and not completely accurate. Please let me know in the comments about any errors I made!
So, I've had tons of requests about optimal exposure time - but first, I want to clarify a bit about gain, offset, dynamic range, read noise, and how they're all linked together - and at the same time, how to choose the "right" values for them (there's no right values, but I'm lazy, so I just choose something that seems like it makes sense!). Hopefully this is helpful!
Dr Robin Glover videos: https://www.youtube.com/watch?v=3RH93UvP358
And the follow-up: https://www.youtube.com/watch?v=ub1HjvlCJ5Y
#astrophotography