Sigma 170-500mm f/5.0-5.3 DG Lens for Pentax Digital SLR Cameras Ultra-telephoto zoom up to 500 millimeters ideal for sport, nature, and landscapes Multi-layer lens coating and design reduces flare and ghosting Aspherical lenses and SLD glass corrects aberration throughout entire zoom range Rear focus system ensures fast autofocus For Pentax 35mm and digital SLR cameras; includes lens hood and removable tripod collar