Featuring a unique optical design and paired with advanced image stabilization technologies, the Canon EF 400mm f/4 DO IS II USM Lens is a super telephoto lens designed for full-frame EOS DSLRs. Gapless dual-layer diffractive optics are employed within this lens' construction to produce a smaller, lighter weight 400mm option with enhanced correction for chromatic and spherical aberrations. Aspherical and UD elements are also utilized to further reduce distortions and optimized coatings contribute to increased clarity and contrast. Complementing the sophisticated optical layout, a four stop-effective Optical Image Stabilizer helps to minimize the appearance of camera shake and can be dedicated to different styles of shooting. Ideally positioned as a versatile option for sports and wildlife photographers, this lens' high-performance attributes and natural handling render this a viable telephoto option for a variety of applications. Housed within a weather-resistant barrel, this lens also features fluorine coatings on the front and rear elements for protection against fingerprints and other elements from affecting image quality. Focusing handling is complemented by the inclusion of AF stop buttons at the front of the lens, as well as full-time manual focus override and Power Focus mode for smooth shifting of focus.