Sigma EF 85mm f/1.4 DG HSM Art

Sigma looked to create a peak portrait prime with the 85mm f/1.4 DG HSM Art Lens, and they delivered an optic with high performance, a large f/1.4 aperture, and a variety of technologies. Available here with a Canon EF mount, this lens offers a super-fast f/1.4 aperture that is great for getting images with an exceptionally shallow depth of field and smooth bokeh. It also uses two SLD elements, one anomalous partial dispersion/high-refractive index element, and one aspherical element that minimize aberrations and ensures a crisp, clear image. A Super Multi-Layer coating helps by suppressing flare and ghosting.

Complementing the optical performance is an equally adept Hyper Sonic Motor, which provides fast, smooth, and near-silent autofocus performance. This focusing motor also enables full-time manual focus override at any time just by rotating the focus ring for refined manual control and focusing as close as 10.9". The lens barrel is constructed using a Thermally Stable Composite material, which supports working in a wide variety of temperatures and conditions, and the lens mount is constructed from brass for long-term durability and mounting accuracy. Additionally, this lens is also compatible with the optional Sigma USB Dock for fine-tuned control over focusing parameters and other lens characteristics.

Exclusive low-dispersion glass
The degree to which light is refracted by glass depends on the light's wavelength. This fact causes different colors of light to focus at slightly different points. The result is chromatic aberration, the color 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.

Focus

• A large HSM, AF with full-time manual focus and all of SIGMA’s latest design and manufacturing technologies help deliver an entirely new visual experience.
• The large hypersonic motor (HSM) delivers ample torque to the focusing group for outstanding speed, ensuring exceptionally stable performance even at lower speeds. Along with the optimized AF algorithm, this feature delivers fast autofocus photography.
• Full-time manual focus function allows the lens to be switched to manual focus simply by rotating the focus ring.