SMC Pentax FA 50mm f/1.4 Compact, Standard Lens Extremely Large F/1.4 Aperture Allows Extra-fast Shutter Speeds & Wonderful Depth Of Field Control Focal Length Equivalent To 75mm When Used On A Pentax(r) Digital SLR Camera Body (1.5x Crop Factor) Pentax(r) Super Multi-coating For Very Low Light Loss Compatible With All Pentax(r) Film & Digital SLR Cameras Only 1.5 inches and 7.8 ounces 47 degree angle of view Fixed 50mm focal length Fully automatic diaphragm Lens construction of 6 elements in 5 groups