IMO you're confusing Depht Of Field (DOF) and focusing....
The two sets of images are not totally comparable as their magnification are different: in the first set the subjects were larger and the DOF were shallower than the 2nd set which has more background into focus which make the images appear to be sharper. As you'll find later shallow DOF is something quite desirable when you want to isolate the subject from the background as you'll gain more experience with 'faster' lenses
-> As to the rotation of the zoom, the Sigma is designed to fit multiple bodies so it has to pick one... If you had come from a Nikon family instead then its zoom rotation is in the same direction as the Nikkor I shoot with multiple bodies so it's something I just get use to
Last edited by NHL; Oct 20, 2009 at 8:26 PM.