Sigma 800mm f/5.6 APO DG EX HSM is an ultra telephoto lens designed for full frame sensors, but for use with APS-C size sensors with a corresponding effective increase in focal length to about 1200mm. This telephoto lens employs a larger aperture and ELD (extraordinary low dispersion) glass for optimum color correction and sharpness. Its Super Multi-layer coating minimizes flare and ghosting. The lens houses Hyper Sonic Motor to ensure precise, quiet and fast autofocusing. The 800mm f/5.6 is an exceptional lens for sports and wildlife photography.