The Canon EF-mount Sigma 70-200mm f/2.8 DG OS HSM Sports Lens is a flexible telephoto zoom characterized by its bright and sophisticated design. The fast constant f/2.8 maximum aperture excels in difficult lighting conditions and also offers increased control over the depth of field for isolating subjects. Regarding the optical layout, an impressive 10 low-dispersion elements are used to greatly reduce chromatic aberrations and color fringing for improved clarity and color accuracy.A Hyper Sonic Motor is also used to provide quick and quiet autofocus performance along with full-time manual focus override. The physical design of the lens also incorporates several seals to guard against dust and moisture, and a water- and oil-repellent coating has been applied to the exposed elements to prevent moisture, fingerprints, or smudges from sticking to the surface. As part of the Sports line within Sigma's Global Vision series, this lens is designed to offer excellent optical performance, speed, and other customizable features that make it an ideal choice for wildlife, sports, action, and other fast-moving subjects. Constant f/2.8 maximum aperture is well-suited for working in low-light conditions and also provides greater control over the focus position when using shallow depth-of-field techniques. A Super Multi-Layer Coating has been applied to lens elements to minimize lens flare and ghosting and contribute to producing contrast-rich and color-neutral imagery, even in backlit conditions. The rounded 11-blade diaphragm contributes to a smooth and pleasing bokeh quality. An Intelligent Optical Stabilizer system minimizes the appearance of camera shake to benefit from making sharper imagery when shooting handheld. This lens is compatible with the optional Sigma USB Dock for fine-tuning different lens characteristics and updating its firmware.