The Sigma 50mm f/1.4 EX DG HSM Autofocus Lens is a standard lens that provides a large maximum aperture of f/1.4. It is the ideal prime lens for use with all Canon digital or film SLR cameras. When used on Canon digital SLR cameras with the APS-C size sensor, the equivalent focal length of this lens will be 80mm, which makes it an excellent choice as a bright medium telephoto lens. Its large f/1.4 aperture allows for sharply defined contrasty images against a nicely blurred background. The lens offers superior peripheral brightness even at the maximum aperture, and corrects for possible flare.