I was a little disappointed when I first received it from Ken Hansen and it was larger than my Rigid 50 summicron, but lighter. I actually LOVED the aperture ring though, nice smooth audible clicks. I shoot it on an M3 or M4, so I don't have the meter as well to check me if I change it, but I've never had the problem with even "spontaneously fast" focusing. The contrast in the out of focus areas and their rendering just floored me.