75-300mm f/4-5.6 III EF telephoto lens * effective focal length: * 75-300mm with 35mm film or full-frame sensor digital cameras * 120-480mm with APS-C sensor Canon cameras * compatible with all Canon autofocus film and digital SLR cameras * Micro USM (Ultrasonic Motor) * constructed of 13 elements in 9 groups * lens is 5-3/8 long, 2-13/16 in diameter * more info