Sigma bolsters its top-end EX range with the announcement of a HSM focusing-motor-equipped 50mm f/1.4 lens. Offering a moderate telephoto field of view on APS-C cameras, Sigma's DG designation means it will also work as a standard lens on full-frame digital cameras. We believe this is the first time a 50mm f/1.4 lens has been offered with a ring-type focus motor. Pricing and availability information to follow as soon as we have it.

Source: News: Digital Photography Review (dpreview.com)