[JJ_SO]

"it may focus faster and more accurately" - any source for this statement of belief?  Or just the usual Canon fanboy stuff? Besides, neither Canon, Nikon or Sigma have problems focusing fast enough. And if it comes to accuracy, the lens' part of Sigma is pretty well adjustable to the camera part of the AF process. Contrary to the big boys where you need to decide if you go for close distance accuracy or distant subjects.

 

Actually, I just shot a couple of wide open stuff in daylight where the subjects were as well in center as also at the borders - to me this situation is not that rare not to think about. But depending how quick I need to be to get the shot, it really doesn't matter if the edges are blurred because a lack of DoF or inaccurate focusing or blurred edges from the lens' side. However, I eventually get some sharp corners insteaf of being completely at the "sharp corners are impossible" side