Sigma 50mm f/1.4 EX DG HSM Autofocus Lens for Sony & Minolta Designed for use with full frame digital cameras. May also be used with smaller APS-c size sensors with a corresponding effective increase in focal length to about 90mm with most cameras Designed with molded glass aspherical lens elements for superior corrections of chromatic aberration & high image quality at all working distances 9-blade diaphragm creates a pleasant out-of-focus- effect on backgrounds