Pentax D Fa 645 55Mm F2.8 Al[If] Sdm Aw Lens

This Pentax-D FA 645 55mm f/2.8 AL[IF] SDM AW Lens is the first model of the Pentax-D FA 645 lens series created for the Pentax 645D digital medium-format camera. With a focal length that's equivalent to a 43.5mm standard lens (in 35mm), it features optics optimized for digital photography to assure exceptional performance, and also provides an image circle covering the image area of existing 645-format film SLR cameras. It has dependable, dust-proof, weather-resistant construction for active outdoor photography. 

This lens features a Supersonic Direct-drive Motor (SDM) autofocus drive and Quick-Shift for instant autofocus/manual focus switching,  Aero Bright coating to help prevent flare and ghost images, and it's Pentax's first 645 system lens to incorporate a rounded diaphragm for improved bokeh (the aesthetic quality of the blur in the out-of-focus areas of an image).