The EF 100-400mm f/4.5-5.6L IS II USM Lens from Canon is a L-series super telephoto zoom offering a versatile focal length range along with a constant maximum aperture for consistent performance throughout the zoom range. The optical design incorporates one fluorite element and one UD element, which help to achieve impressive sharpness and clarity while minimizing chromatic aberrations and distortions. Also, a Subwavelength Coating has been applied to reduce ghosting and flaring for increased contrast and color fidelity when working in strong lighting conditions. The optical design incorporates one fluorite element and one UD element, which help to achieve impressive sharpness and clarity while minimizing chromatic aberrations and distortions. Also, a Subwavelength Coating has been applied to reduce ghosting and flaring for increased contrast and color fidelity when working in strong lighting conditions.