(Taken directly from Sigma 50mm f/1.4: A new standard?: Digital Photography Review)

Quote Originally Posted by DPReview.com
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.

Press Release:



The Sigma Corporation is pleased to announce the new large aperture 50mm F1.4 EX DG HSM standard lens. For Sigma, Canon, Nikon, Pentax* and Sony*

Standard lens with large maximum aperture of F1.4.
  • It creates sharp images with high contrast and ensures superior peripheral brightness.
  • Incorporates molded glass aspherical lens, perfectly correcting coma aberration and creating superior image quality.
  • Super multi-layer coating reduces flare and ghosting.
  • Hyper Sonic Motor (HSM) ensuring silent, high-speed AF

This is a large aperture prime lens with a standard focal length of 50mm, ideal for digital cameras. This lens is perfectly suited for a wide range of subjects enabling outstanding, sharply defined images against a nicely blurred background. The fast, F1.4 aperture makes this lens desirable for use with Digital SLR cameras. This lens effectively becomes an 80mm medium telephoto lens on digital cameras with APS-C size image sensors. The optimum optical design and molded glass aspherical lens elements provide excellent correction for all types of aberrations. This lens has superior peripheral brightness and provides sharp, high contrast images even at the maximum aperture. Superior optical performance is also ensured throughout the focusing range. The super multi-layer lens coating reduces flare and ghosting. This lens has a minimum focusing distance of 45cm (17.7”) and has maximum magnification of 1:7.4. It creates a very attractive blur, even when a small aperture is used.

This lens incorporates HSM (Hyper Sonic Motor), which ensures a quiet and high-speed AF as
well as full-time manual focus override.

* If the camera body does not support HSM motor, AF does not work.
I guess saying "has good bokeh" at the end would just confuse people