I keep getting images like the attached one that just appear soft for some reason (this is straight out of camera). I thought it might have been camera shake, but I was shooting at 1/1600th, and I'm typically a very stable person. Any thoughts? It was taken on a 70-200mm f/2.9 is ii usm with a 5d mk iii body. I'm just about ready to send the lens in but figured I'd post here first. Thanks!!