The Canon EF 70-200mm f/2.8L USM telephoto zoom lens is one of the finest telephoto zoom lenses in the EF line, comparable to a single focal length Lens. It has four ud-glass elements to correct chromatic aberrations. Its constant f/2.8 maximum aperture and superb image quality make it one of the most popular professional SLR Lenses in the world. Compatible with extender EF 1.4x II and 2x II. Features: EF mount, telephoto zoom lens ultra-low dispersion glass, inner focusing, full-time manual focus 70-200mm focal length F2.8 constant maximum apertureultrasonic motor (USM). Diagonal Angle of View: 34 - 12 degrees, Filter size: 77 mm, Closest Focusing Distance: 4.9 feet. One of the finest telephoto zoom lenses in Canon's EF line, this 70-200mm f/2.8 lens offers comparable optics to a single focal-length lens. The lens employs four UD-glass elements to minimize chromatic aberrations, creating sharp, high-quality images regardless of the application. The constant f/2.8 maximum aperture, meanwhile, makes the lens extremely popular among professionals. Other features include an inner focusing system with an Ultra Sonic Motor (USM), a 4.9-foot close focusing distance, and a 77mm filter size. The lens which is compatible with EF 1.4x II and 2x II extenders--carries a 1 year warranty.