Canon EF 70-200mm f/2.8L IS II USM Telephoto Zoom Lens for Canon SLR Cameras 70-200 mm focal length and 1:2.8 maximum aperture Lens construction consists of 23 elements in 19 groups (1 fluorite and 5 UD elements) 34-Degree - 12-Degree diagonal angle of view Inner focusing system with USM and full-time manual focus option 77 mm filter size. Extenders Compatible