The Pentax smc FA 645 55-110mm f/5.6 Lens is a standard zoom lens designed for Pentax 645 mount medium format cameras, both film and digital. It is designed for general shooting and has a standard to medium telephoto field of view with a 35mm equivalent focal length of 43.5-87mm. Also, it has a constant minimum aperture of f/5.6 and can stop down to f/45.
The lens design features 9 elements in 9 groups which feature a Super Multi Coating that prevents ghosting and flaring. For optimal image quality, the 55-110mm uses extra-low dispersion glass elements to prevent chromatic aberrations and maximize contrast and sharpness. Also, the lens will focus as close as 2.6'.
For smooth out-of-focus areas, the lens has an eight blade aperture diaphragm. There is also an 82mm front filter thread.