This is the first Sigma 50mm f/1.4 prime lens for 4/3 DSLRs, a tele photo lens in the focal length of 100mm equivalent to portrait lens in medium distance. A superb lens of optical quality and design, fast focus in silent with HSM.

Fast aperature in f/1.4 with beautiful bokeh; Short lens barrel and well balance of weight by hand-held with camera body; Fast focus speed in silent with HSM

Similar in size, features, and price (though not format) to Sigma's 30mm f/1.4 high-speed "normal" prime for DSLRs with APS-C sensors, this 50mm full-framer ($500, street) also belongs to Sigma's EX family of pro-quality glass.

It is hard not to be drawn to a fast prime - the short, fat, solid-feeling lens with very low-light capability is very attractive. So, I don't find it surprising that the Sigma 50mm f/1.4 EX DG HSM Lens has received a lot of attention in the early days of its availability.

The pictures below illustrate the angles of view on 35mm full frame and APS-C (1.6x crop) camera bodies. Our observations indicate that the focal length is noticeably shorter than the specified 50mm (probably closer to 47mm):

Class-leading image quality; Relatively low vignetting even at wide apertures on full frame; Reasonably fast and positive autofocus; with full-time manual override; Very good build quality

Large and heavy for a 50mm F1.4; Expensive

The 50mm f/1.4 EX DG HSM is the first large-aperture 50mm prime lens to be manufactured by Sigma and the company has gone to considerable lengths to include the latest designs and technology.

Although zoom lenses are certainly versatile and convenient, they do have some drawbacks, including relatively small maximum apertures. A typical 28-90mm equivalent zoom may provide an aperture of f/3.5 at short focal lengths but it will be f/5.6-6.3 at longer zoom settings.