I like to go out shooting wildlife, but my current lens (SIGMA 50-500mm) gives me great dissapointment, because things at a distance (say 200 yards) are never quite as sharp as I'd like. Yes, I use a tripod when I can, but I'm still dissapointed; even sharpening in Photoshop doesn't do what I'd like. I've heard that one problem is that becuase of the range, there is just too much glass in the lens, and that I should switch to 200-500MM. I'm using a Minolta Maxxum 7D and I get splendid results with other lenses. So, do you think I will see any discernible difference if I switch to a 200-500MM?