Telephoto zoom lens series pentax smc da lens mounts pentax k pentax kaf2 lens speed 28 focal length 50 135 mm zoom factor 27 times suitable for sensor type aps c construction zoom lens area of use indoor photography portrait photography close up photography night photography sports photography focus internal focus auto focus manual focus af motors ultrasonic motor usm supersonic dynamic motor sdm reduced frame size max magnification 15 9 di