The Sigma 50mm f/1.4 EX DG HSM is a standard prime lens with a large aperture ideal for various styles of photography. The Sigma 50 f/1.4 concerts sharp images with high contrast and promises ultimate peripheral brightness. The lens is coupled with molded glass aspherical lens elements, correcting chromatic aberration and producing high image quality. The HSM designation of the lens ensures silent, high-speed AF. The Sigma 50mm f/1.4 effectively becomes a 80mm medium telephoto lens on DSLRs with APS-C sized sensors.