The Sigma 800mm f/5.6 EX DG APO HSM is an apochromatic extreme-telephoto lens with a fast f/5.6 maximum aperture. The ultra-quiet Hyper Sonic Motor (H.S.M.) and Internal Focusing features assist autofocus speed and handling. The improved DG lens design corrects for various aberrations. This lens is specially coated to get the best color balance whilst cutting down on ghosting caused by reflections from the digital image sensor. This lens is ideal for capturing wildlife and sports photography.