One of the sharpest lenses in the entire EOS system, and a brilliant all-round telephoto lens that can focus to true life size (1x) with a working distance of almost 10 inches (0.25m) from the subject! Three UD-glass elements, a floating optical system, and internal focusing assure superb performance at any distance. It's even compatible with the EF 1.4x II and 2x II tele extenders. A powerful ring-type USM means fast and silent AF, along with full-time manual focus. It includes a tripod collar and detachable lens hood.