I'm sorry, after looking at dolina's reply and the chart for A7rii, I don't see how those answers correspond. I have an A7, the curve looks linear throughout (except from 50-100), does that mean that I'll just get equivalent noise gain as I move up the iso range and I can avoid the whole (160, 320, etc) stepping from my Canon days?
edit- I looked at Canon 5d and 5dii, I think I'm right