The Sigma 800mm F5.6 EX APO DG HSM is a ultra telephoto zoom designed for Full Frame Sensors but may also be used with smaller APS-C size sensors with a corresponding effective increase in focal length to about 1200 with most cameras. A Hyper Sonic Motor (HSM) ensures quiet, high speed and accurate autofocusing while Super Multi-Layer Coating reduces flare and ghosting. Two ELD (Extraordinary Low Dispersion) glass elements provide optimum color correction and sharpness throughout the entire zoom range. A new multi-layer lens coating technology and lens design formula reduces flare and ghosting. Rear insertion 46mm filters with provision for easy rotation of polarizing filters. Compatible with the Sigma’s APO dedicated Tele converter 1.4x and 2x to provide additional focal length as a 1120mm F8 MF or 1600mm F11MF lens respectively. The Sigma 800mm F5.6 is a superb lens for sports and wildlife photography.