The smc FA 645 150mm f/2.8 IF Lens from Pentax is a medium format, manual and autofocusing telephoto lens with a 35mm-equivalent focal length of 118mm. Its fairly fast f/2.8 maximum aperture enables effective low-light shooting with pretty shallow depth of field, and helps produce a natural out-of-focus (bokeh) effect for backgrounds. High-refraction and extra-low dispersion glass help minimize chromatic aberrations and allow for sharp imaging performance with high contrast and clarity. The Super Multi Coating also contributes to high sharpness and contrast. An inner focus system is used to minimize lens extension when focusing, allowing for a closer minimum focus distance. A large hood with a PL filter operation window is included to enable the use of a circular polarizing filter while checking the results through the camera's viewfinder.