It’s sometimes hard to believe that there are focal length and aperture values that have yet to be paired, but such is the case with Sigma’s newest Art lens, which the company says is the world’s first 20mm f/1.4 lens. The full-frame lens is available in Nikon, Canon and Sigma mounts, and offers a 30mm angle of view for Nikon APS-C cameras and a 32mm angle of view for Canon APS-C cameras. There’s plenty of chemistry on hand to keep optical maladies to a minimum. There’s “F” Low Dispersion (FLD) glass and five Special Low Dispersion (SLD) glass elements to reduce spherical aberration, axial chromatic aberration and field curvature. Thanks to the use of Super Multi-Layer Coatings, the lens is also resistant to strong incidental light sources such as backlight. Focusing is driven by a hyper sonic motor for silent, speedy operation. It offers a nine-blade rounded aperture and a brass bayonet mount. While the 20mm has a bright f/1.4 aperture it can be stopped down to f/16 and has a minimum focusing distance of 10.9 inches. The 20mm Art lens is built from a Thermally Stable Composite compound which can endure extreme temperatures while not being overly heavy at 2.1 pounds. This lens is compatible with Sigma’s optional USB Dock, which allows photographers to update the lens’s firmware, adjust focus points and customize full-time manual focus over-ride function settings using Sigma’s Optimization Pro software.