I was given a Sigma lens for a Nikon 70 (film SLR) years ago, and then started using it on my Nikon D80 (digital SLR) this past year with mixed results. I won’t go into why I felt short-handed with the old lens, but will say that I was not entirely unhappy when I dropped the camera right on the lens while cavorting with the dogs down by the Yellowstone River. The ground was pretty soft, and the D80 is unscathed, thank goodness. However, I now have an excuse to buy a new and better lens. (I will confess that I am neither a patient or a gifted amateur photographer, but I know very well that...