Pairing a favored super telephoto focal length with a bright f/2.8 maximum aperture, the EF 400mm f/2.8L IS II USM is a Canon L-series optic well-suited for outdoor, wildlife, and sports applications. The fast maximum aperture enables extensive control over depth of field for isolating subjects using selective focus, and it also benefits working in difficult lighting conditions. Two fluorite elements are used in the optical design to help reduce color fringing and chromatic aberrations for high clarity and color accuracy and a Sub Wavelength Coating has been applied to individual elements to suppress flare and ghosting for increased contrast and color neutrality when working in backlit conditions. Beyond the optical attributes, this 400mm f/2.8 is also characterized by its advanced four stop-effective Image Stabilizer system, which has three separate stabilization modes to suit various shooting applications. Also complementing handling is a sophisticated ring-type USM, which provides quick, quiet, and accurate autofocus performance along with full-time manual focus override. Additionally, this lens is weather-sealed for use in trying environmental conditions and it has a removable rotating tripod collar to benefit working atop a tripod or monopod. Super telephoto prime is designed for full-frame Canon EF-mount DSLRs, however can also be used with APS-C models where it provides a 640mm equivalent focal length. Fast f/2.8 maximum aperture benefits working in low-light conditions and also affords significant control over depth of field for working with selective focus techniques. Two fluorite elements are used to greatly reduce color fringing and chromatic aberrations in order to achieve greater clarity and color accuracy. A Sub Wavelength Coating has been applied to individual elements to control lens flare and ghosting for greater contrast and color fidelity when working in strong lighting conditions. An Optical Image Stabilizer helps to minimize the appearance of camera shake by up to four shutter speed stops to better enable working in low-light conditions and with slower shutter speeds. Three distinct IS modes are available: standard single-shot mode, a panning-optimized mode, and a mode that only activates the Image Stabilizer during the exposure. A ring-type Ultrasonic Motor (USM), along with optimized focusing algorithms and a high-speed CPU, is employed to deliver fast, precise, and quiet autofocus performance as well as full-time manual focus override. Focus Preset function is available to quickly recall a programmed focusing position. Focus Limiter switch lets you constrain the focusing to three different ranges to suit different applications: 8.9-23', 23'-infinity, or 8.9'-infinity. A Power Focus setting is available, and allows you to electronically and smoothly adjust your focus position to suit video recording. This setting utilizes a dedicated ring in front of the main focusing ring and allows you to use one of two different focusing speeds. Rounded nine-blade diaphragm contributes to a pleasing out of focus quality that benefits the use of shallow depth of field and selective focus techniques. As a member of the esteemed L-series, this lens is sealed against dust and moisture for working in inclement environmental conditions. Removable rotating tripod collar is included and benefits working with the lens atop a tripod or monopod. Compatible with optional EF 1.4X and EF 2X teleconverters.