sonofstan I actually wrote this before I had a chance to test the autofocus. I was comparing what 10 steps translated to (on the fine focus wheel) compared to what I would do when focusing manually with a bahtinov mask, and it seemed huge. In practice however, it works fine, as the AAP takes several exposures at various focus points, and then goes to the bottom of the curve, even if that point is between the steps used to take the measurements. I am actually quite content with this, now that I understand it better. I am imaging at f4.7 though, I could see how these steps might still be too big for someone imaging around f/2.