The Sigma 105mm f2.8 EX Macro delivers superb, distortion-free images throughout its broad focus range, from infinity telephoto to 1:1 (life-size) macro, as close as 12.3" without accessories. Its non-rotating front lens group makes it easier to work with polarizing filters and has a focus limiter (eg. Full Range; - 15.8 in.; 14.6 in. - 12.3 in.). A "focus-free" mechanical design allows the lens to auto focus without any interference from the manual focus ring. This makes it easier to hold the lens without affecting the speed or normal operation of the autofocus function. Rugged mechanical construction also makes it durable enough for even the heaviest use required by professional photographers. The Sigma 105mm f2.8 EX Macro features the new deluxe external EX finish. These features and other Sigma optical advances, including an uncommonly broad range of focus, make this an ideal lens for a wide variety of applications, from nature photography to portraits. A handy optional screw-in type metal sunshade makes it easier to rotate a polarizing filter.