FeaturesCompatible with Canon EF mountOptical stabilizer (OS) systemSuper multi-layer coatingUltra-telephoto lensFour SLD glass lens elementsThe Sigma 100-400mm f/5-6.3 DG OS HSM I Contemporary Lens for Canon EF Mount has an ultra-telephoto lens with an optical stabilizer (OS) system that has several advantages. The OS allows the photographer to take photographs in unstable circumstances. The narrow-angle of view makes it possible to dramatically compress perspective and flexible handling of the background. The photographer can thereby make the subject appear to jump out of the image, with the area in focus impressively sharp and clear. This lens offers the compact size, lightweight, and high-cost performance of a 70-300mm lens while delivering 400mm telephoto performance. This approach results in a tempting new ultra-telephoto choice for photographers. Offering a combination of stunning image quality and outstanding functionality, this lens satisfies the needs of pros and amateurs alike.Compact packaging with uncompromising image quality In designing this lens, SIGMA strived to push both compactness and image quality to the limit. Four SLD glass lens elements and an optimized power distribution help minimize optical aberrations. Moreover, by taking special care to minimize transverse chromatic aberration, which cannot be corrected via aperture control, SIGMA has ensured outstanding image quality throughout the zoom range. Telephoto plus macro functionality With a minimum shooting distance of 160cm and a maximum magnification ratio of 1:3.8, this lens can shoot either from a distance or up close. Exclusive low-dispersion glassThe degree to which light is refracted by glass depends on the light\'s wavelength. This fact causes different colours of light to focus at slightly different points. The result is a chromatic aberration, the colour fringing that is particularly noticeable in telephoto lenses. Most chromatic aberration can be removed by combining a high-refractivity convex lens element with a low-refractivity concave element. Yet residual chromatic aberration known as the secondary spectrum may still remain. To minimize this secondary spectrum, which can be a serious issue with conventional lenses, SIGMA lenses feature up to three types of exclusive low-dispersion glass offering superior performance: ELD (Extraordinary Low Dispersion), SLD (Special Low Dispersion) and FLD (F Low Dispersion). In particular, FLD glass offers ultra-low dispersion in combination with high transmittance and the anomalous dispersion characteristics of fluorite. Meticulous deployment of these types of exclusive low-dispersion glass and optimization of power distribution gives SIGMA lenses superlative image rendition undiminished by residual chromatic aberration. Designed to minimize flare and ghosting Sigmas Super Multi-Layer Coating helps further reduce flare and ghosting and provide sharp, high-contrast images even in backlit conditions. All-new optical stabilizer (OS) unit with an exclusive algorithm Featuring a newly developed gyroscopic sensor and a new and exclusive algorithm, the all-new OS unit provides a powerful stabilization effect. An acceleration sensor detects camera shake in any direction - horizontal, vertical, or diagonal. This technology allows the OS to stabilize the image very effectively, regardless of whether the camera is being held in a horizontal or vertical orientation. Push/pull zoom mechanism incorporated For quick control of the angle of view, the zoom ring incorporates a push/pull mechanism in addition to the regular twist mechanism. The exclusive lens hood has also been designed to accommodate push/pull zooming and overall lens manoeuvrability. By making it possible to adjust the angle of view instantly, this lens gives photographers an even better chance of getting that crucial shot. Rounded diaphragm The 9-blade rounded diaphragm creates an attractive blur in the out-of-focus areas of the image. Smoother AF operation The HSM (Hyper Sonic Motor) ensures high speed and quiet AF. The updated algorithm enables smoother AF operation. High-precision, rugged brass bayonet mount The brass mount combines high precision with rugged construction. Its treated surfaces and enhanced strength contribute to the exceptional durability of the lens. Dust-proof and splash-proof mount. The lens mount incorporates rubber sealing* to protect the mount from dust and water drops. * Except for the SIGMA mount