Sony is on its second version of a pro-level 70-200mm f/2.8 G Master lens. Tamron recently released its second 70-180 f/2.8 G2 lens. A professional 70-200mm f/2.8 was one of the first lenses released by Panasonic for its Lumix full-frame bodies. And in all this time, where has Sigma been? Well, the wait is over. Sigma has finally released the 70-200mm f/2.8 DG DN OS Sports series lens, but was it worth the wait?