Sigma 120-300mm f/2.8 EX DG IF HSM APO Telephoto Zoom Lens for Canon SLR Cameras Features a large aperture of f/2.8 at the 300 millimeter focal length Multi-layer lens coating and lens design reduces flare and ghosting Features SLD (Special Low Dispersion) glass elements for superior correction of chromatic aberration Hyper Sonic Motor (HSM) for ultra-quiet shooting