Designed for use with Digital SLR's the Sigma 50mm f 1. 4 EX DG HSM is a fast aperture prime lens ideal for portraiture work, particularly with APS-C size Sensor Digital SLRs where it is the equivalent of an 80mm lens. The Sigma 50mm f 1. 4 EX DG HSM lens produces vivid images on a pleasantly blurred background. The lens features optimum optical design & molded glass aspherical lens elements, which deliver excellent correction for all types of aberrations. With a minimum focusing distance of 45 cm (17. 7") & a maximum magnification of 1: 7.4, outstanding optical performance is ensured throughout the entire focusing range. Incorporating HSM (Hyper Sonic Motor), which ensures a quiet & high speed AF as well as full-time manual focus override, the Sigma 50mm f 1. 4 EX DG HSM lens performs to a high standard in all shooting situations.