The Pentax smc FA 645 150-300mm f/5.6 ED [IF] Lens is a telephoto zoom lens designed for medium-format Pentax 645 mount cameras. It has an aperture range of f/5.6-45, and when used on 645 cameras, the lens has a 35mm equivalent focal length of 118.5-237mm. This gives you a wide, versatile range of telephoto focal lengths to choose from during shooting.
This lens has a construction of 15 elements in 13 groups that is designed for high quality images. It even has extra-low dispersion glass elements that minimize the effects of chromatic aberrations and provide high contrast images for maximum resolution. This is all protected by a Super Protect (SP) coating on the front element that lessens the possibility of scratches and makes it easier to clean.
During operation, the lens internally focuses, keeping the large lens as compact as possible, and it switches from auto to manual focus by sliding the focus ring forward or backward. The lens also has a minimum focus distance of 6.6' and a filter thread size of 67mm.
35mm focal length equivalent of 118.5-237mm
Aperture range of f/5.6 to f/45
Angle of view of 21° to 10.5° which equates to 17° to 8.5° on Pentax 645 digital cameras
Lens construction of 15 elements in 13 groups
Two extra-low dispersion glass elements help to minimize chromatic aberrations and maximize sharpness
Accepts 67mm threaded filters
Minimum focusing distance throughout the zoom range is 6.6'
Super Protect coating on the front element helps keeps your lens scratch free and easy to clean
Internal focusing keeps the lens as compact as possible during use
Works with both film and digital formats
Aperture ring and focusing distance scale
Eight diaphragm blades for smooth out-of-focus areas