The Pentax smc FA 645 80-160mm f/4.5 Lens is a medium telephoto zoom lens with a 35mm equivalent focal length of 63-126.5mm and a maximum aperture of f/4.5. The autofocus lens can stop down to f/32 and features multiple types of low dispersion glass elements throughout its 11 element and 10 group construction. This is benefited by the use of a Super Multi Coating that helps eliminate flare and ghosting.