Sigma 500mm F4.5 EX DG HSM
The AF drive for Sigma SA, Canon and Nikon S.L.R. cameras features Sigma's ultra-quiet and high-speed Hyper Sonic Motor (HSM). It also features a drop-in 46mm filter holder in the rear part of the lens barrel, which can be rotated to facilitate the use of filters, including a polarizing filter. By adding an APO teleconverter (optional extra), you can use this lens as a 700mm f/6.3 MF ultra-telephoto lens with a 1.4X EX teleconverter, or as a 1000mm F9 MF ultra-telephoto lens with a 2X teleconverter.