I am a really big fan of this lens, had it for a good long time. I use it mostly for for wildlife as seen from this picture of Roxy(which I have edited the background to lessen the effect of the fence that was in-between us). Perhaps only my copy, I can only take pictures at f2.8 to get sharp pictures as when I stop down the focus is almost always out at f3.2 to f7.1. Focus accuracy or perhaps just the DOF increase improves at f8 and f11.