Focal length and maximum aperture: 75-300mm 1:4-5.6, Lens construction: 13 elements in 9 groups Diagonal angle of view: 32 Degree 11 ft. - 8 Degree 15 ft, Front group rotating extension system with USM focus adjustment Closest focusing distance: 1.5m/4.9 ft. 75-300mm telephoto zoom lens with f/4.5-5.6 maximum aperture for Canon SLR cameras Micro ultra-sonic monitor (USM) makes autofocusing quicker and quieter than before