> I'm not quite sure if near or farsightedness neither diopter adjustment > plays a role. I made up a thread with a very similar problem, and my > thoughts led me to the idea that focussing is always done on the > viewfinder screen, and diopter adjustment just makes me see the screen > better or worth, but doesn't influence focussing. I think it's two > different systems.
I do believe that this is true. Nearsightedness and farsightedness (and, in fact, presbyopia, astigmatism, etc.) only hinder one's ability to see the focus screen, and do not actually affect the focus, at least in the sense of somehow "skewing" focusing direction toward "too close" or "too far". The only negative effect (and I'm not really making light of this) of these eye conditions is merely to make focusing more difficult because seeing the focus screen becomes more difficult. Fred
