Telephoto lens series pentax smc fa lens mounts pentax k pentax kaf lens speed 18 focal length 77 mm suitable for sensor types aps c full frame construction prime lens area of use night photography astrophotography portrait photography action photography focus auto focus manual focus af motor no internal af motor max magnification 17 closest focusing distance 70 cm focal length equivalent to 35mm camera 116 mm lens type aspherical lens constructi