The Canon EF 135mm f/2L USM 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/2 wide aperture. The EF 135mm f/2L USM is fully compatible for AF with Extenders 1.4x and 2x. A stellar portrait and available light lens.