FeaturesCompatible with Canon EF mountHyper Sonic Motor (HSM)SLD (Special Low Dispersion Glass)Super multi-layer coating14 lens elements in 12 groupsPortrait photographers demand the attractive bokeh effect that large-diameter lenses offer, as well as outstanding resolution. Fulfilling the exacting standards of the Art line, the Sigma 85mm f/1.4 DG HSM Art Lens for Canon EF Mount delivers both of these elements at the highest level. The bokeh effect is so precise, you can focus on the pupil of the subjects eye while blurring the eyelashes. Adding to the effect, the area in focus is extremely high-resolution while the bokeh area is very attractive in appearance. The SIGMA 85mm F1.4 DG HSM Art incorporates 14 lens elements in 12 groups, a remarkable structure that helps the lens deliver ultra-high-resolution. This lens is therefore an excellent match for full-frame DSLRs offering 50-megapixel or higher resolution.A design that prioritizes optical performance without compromise. Outstanding resolving power and minimized chromatic aberrations help make this the ultimate lens for portraits. To create a top-performing 85mm F1.4 lens, SIGMA leveraged its latest innovations in design and materials. The result is the ultimate lens for portraits. By taking chromatic aberrations to the absolute minimum, this lens offers performance that goes beyond, including incredibly sharp resolution and a beautiful bokeh effect. The beautiful bokeh effect that only a large-diameter lens can offer Elements made of SLD (Special Low Dispersion) glass and an optimized power distribution help minimize axial chromatic aberration. In the areas in front of and behind the point of focus, the optical system produces an attractive and natural bokeh effect by producing a smooth gradation of focus and minimizing streaking. 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 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 ghostingFrom the start of the design process, SIGMA measured flare and ghosting to establish an optical design that is resistant to strong incidental light sources such as backlight. In addition, SIGMAs Super Multi-Layer Coating helps further reduce flare and ghosting and provide sharp, high-contrast images even in backlit conditions. Newly designed HSM for nimble AF control The newly designed Hyper Sonic Motor (HSM) offers 1.3 times the torque of its predecessor. Even at low speeds, it offers exceptionally stable performance, and the updated AF algorithm helps ensure nimble autofocus performance. In addition, full-time manual focus override allows the lens to be switched to manual focus simply by rotating the focus ring even during continuous AF. The user can quickly find the perfect focus without needing to touch the focus mode switch. Mount with dust- and splash-proof constructionThe lens mount incorporates rubber sealing to protect the mount from dust and water drops. The front and rear lenses feature a water- and oil-repellent coating that is particularly useful when shooting in a drizzle, near ocean spray, and in a wide variety of other conditions. Rounded diaphragmThe 9-blade rounded diaphragm creates an attractive blur in the out-of-focus areas of the image. SpecificationsLens Construction: 14 elements in 12 groupsAngle of View (for SD1): 28.6 degreesNumber of Diaphragm Blades: 9 Blades (Rounded diaphragm) Minimum Aperture: F16Minimum Focusing Distance: 85 cm / 33.5in. Maximum Magnification: 1:8.5Filter Size: Diameter 86mmDimensions: Diameter 94.7mm x Length 126.2mm / 3.7in. x 5.0in. Weight: 1,130g / 39.9oz.