The Sigma 20mm f/1.4 Art DG HSM Lens delivers outstanding large-aperture brightness and bokeh for ultra-wide-angle subjects such as landscapes and starry skies as well as snapshots in low light indoor photography portraits and much more. Two aspherical glass elements minimize distortion throughout the entire image. It features two FLD (F Low Dispersion) glass and five SLD (Special Low Dispersion) glass elements to minimize transverse chromatic aberration. Super Multi-Layer Coating reduces flare and ghosting to help photographers produce sharp and high contrast images even in backlit conditions. The Hyper Sonic Motor (HSM) ensures silent high-speed autofocusing while the optimized AF algorithm helps realize even smoother AF performance.