The Pentax DA 50mm Lens is a fast f/1.8 lens for cameras with a Pentax K mount. Mounted to a camera with an APS-C sensor, this lens gives an angle of view equivalent to a 76.5mm telephoto lens--ideal for portraits. The wide f/1.8 aperture makes this an essential lens for working in low light, and it also delivers beautiful bokeh (the out-of-focus portion of a photograph). This lightweight (4.3 oz) lens is very compact--just 1.5" (3.8 cm) long. Features Very Fast f/1.8 Maximum Aperture Excellent Low-Light Lens Pleasing Bokeh (Out-of-Focus Areas) SP Coating Repels Dust, Water, Grease For APS-C Digital K-Mount Cameras