Used the f2 for a while and not that impressed - OK for the money though I suppose
Ok if stopped down to 5.6 but the 1.4 seems to be in a class of it's own from the samples I've seen ( and the reviews)
I've currently got the f2 and find it a very sharp lens. I often shoot it wide open, with perfectly acceptable results. Stop down a little to f2.5 or f2.8 and the sharpness is excellent. The focus motor is an older design and not usm, but it is very accurate.
The f2 has actually become my most used lens. Because of this, and the fact that I do a lot of low light indoor pictures, I'm thinking of getting the f1.4 as well, but it's a tough call because the f2 is so good. I'd prefer it over the 50mm lenses any day. So much so that I think I'd still keep the f2 for lightweight outdoor walkabout use even if I get the f1.4. It's small and great for this purpose.


