I'm still torn as to which Biogon to get, f/2 or f/2.8. My instinct is to get the 2.8. It's smaller and the reviews I've heard are just fantastic. The thing is, I was hoping to do some low light photography with it, not serious low light stuff, but stuff like indoors without flash photography. Could I get away with the 2.8 in most circumstances like this with, say, pushing Tri-x to 1600?