The Canon EF 135mm f/2L USM high image quality, high performance is designed to meet the needs of a wide range of advanced amateurs and professionals. A ten element optical formula with two UD-glass elements serves to correct residual aberrations,resulting in superb sharpness and high image quality. It is also able to obtain superior background blur with the f/2wide aperture. The EF 135mm f/2L USM is fully compatible for AF and AE Extenders 1.4x and 2x. Item Specifications: Product Description: Canon EF telephoto lens - 135 mm Lens System: Telephoto lens Mounting Type: Canon EF Lens Aperture: F/2.0 Focal Length: 135 mm Min Focus Range: 35.4 in Focus Adjustment: Automatic, manual Lens Construction: 8 group(s) / 10 element(s) Special Functions: Tele Filter Size: 72 mm Length: 4 in Weight: 26.5 oz