The Canon EF 100-400mm f/4.5-5.6 L IS USM - is an excellent professional telephoto zoom lens with a size and weight that still allows for quick handheld shooting. Sufficiently high aperture and built-in image stabilization allow you to shoot at relatively long exposures in low light conditions and without additional illumination. This makes it one of the most widely used and loved by photographers for sports and wildlife photography. The ring-shaped ultrasonic USM autofocus drive and the focusing itself due to the movement of the inner lens group make this process very fast, smooth and quiet. The floating lens system ensures that spherical aberration and coma are corrected when the focusing distance is changed, due to which the image sharpness remains excellent throughout the focal length range. At the same time, the minimum focusing distance is only 1.8 meters. The optical design of the lens is one of the most sophisticated in Canon's entire line of autofocus optics and contains 17 lenses. Of these, two are specifically designed to maximize the correction of chromatic aberration - the scourge of long lenses. One large-diameter artificial crystal fluorite lens is located in the first group of lenses, the second - made of optical extra-low dispersion glass - in the third group. The lens, without any reservations, is suitable for the most difficult and demanding professional photography, including those scenes for which the correct reproduction of similar color shades is crucial (for example, in advertising, portrait photography, shooting flowers and plants, shooting airports and airplanes). The FT-M mechanism allows you to quickly switch from autofocus to manual focusing. Remember that the lens is a pump lens series, i.e. zooming does not take place by turning the ring, as on most Canon lenses, but by moving out the front of the lens.