"Sigma Japan has just announced the imminent launch of its 30mm F1.4 DC HSM Art lens for the Pentax and Sony mounts. This lens was released last year for Sigma, Canon, and Nikon cameras. It is the successor to the now-discontinued Sigma 30mm F1.4 EX DC HSM, one of the most popular Sigma primes previously available for Pentax.
This lens is designed exclusively for APS-C cameras, and as such it is rather compact, measuring 2.5" long (63mm, w/o hood) and weighing in at about a pound (435g). With a focal length of 30mm, it offers a "normal" field of view, delivers roughly the same magnification as what your eyes see. This makes it an excellent everyday prime lens, like 50mm lenses were in the film days. Its maximum aperture of F1.4 lets you go all out with the bokeh and means it will be a great choice for low-light photography."
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http://www.pentaxforums.com/#ixzz2t03M52hV