Fine focusing adjustments with the scroll wheel is impossible on the fly because the minimum number of clicks to register is 2 instead of 1. When I want to determine which of two settings (say .65 and .70) is the sharpest, I have to try my best to do 2 clicks instead of 3. That’s difficult when you’re trying to swap back and forth between two settings. Just one click is all I should need to register an input.