20mm F1.4 DG HSM

World’s first 20mm F1.4 lens —thanks to advanced large-diameter aspherical lens manufacturing technologies To offer an ultra-wide-angle 20mm focal length and F1.4 brightness at wide-open aperture, this lens incorporates a large double aspherical lens 59mm in diameter. Lenses of this type had been considered extremely difficult to manufacture, but Sigma took on the challenge to realize an F1.4 ultra-wide-angle lens that fulfills the strict performance requirements of the Sigma Art line. What made this breakthrough possible were Sigma’s advanced manufacturing technologies, which the company has developed over time by producing a wide range of ultra-wide-angle and large-aperture lenses. For example, milestone lenses such as Sigma 12-24mm F4.5-5.6 EX DG ASPHERICAL HSM, Sigma 8-16mm F4.5-5.6 DC HSM, and Sigma 18-35mm F1.8 DC HSM | Art were completely original products that helped Sigma develop outstanding design and production know-how and its current high-precision, high-efficiency production system. In turn, these advances made possible the new Sigma 20mm F1.4 DG HSM | Art. Moreover, Sigma’s advanced optical design minimizes distortion, transverse chromatic aberration, sagittal coma flare, and the reduction of brightness toward the edges of the image. Delivering top performance even at wide-open aperture, this lens can be considered the culmination of Sigma’s Art line. * Left side: The aspherical glass element incorporated in the Sigma 18-35mm F1.8 DC HSM | Art、Right side: The aspherical glass element incorporated in the Sigma 20mm F1.4 DG HSM | Art.

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.

A refined, integrated design made with the photographer in mind

The Hyper Sonic Motor (HSM) ensures silent, high-speed autofocusing, while the optimized AF algorithm helps realize even smoother AF performance. At any time during AF, users may access MF simply by rotating the focus ring. This feature makes faster focus adjustment possible, since there is no need to use the AF/MF focus mode switch. Also, the optional Sigma USB DOCK allows the user to set the lens to conventional full-time manual focus override.

Note: The operation of full-time MF may vary based on mount type.

The brass mount combines high precision with rugged construction. Its treated surfaces and enhanced strength contribute to the exceptional durability of the lens.

The I series lenses are accompanied by a dedicated magnetic metal lens cap, in addition to a normal plastic cap. This dedicated metal cap clips to the front surface of the lens magnetically. It is no exaggeration to say that this meticulously crafted cap represents the finishing touch for the I series.

The 14mm F1.4 DG | Art is equipped with a wealth of features to support starscape photography. This fully backs up the fun of starscape photography.