Versatile Fast-Aperture Prime. The Sigma 20mm f/1.4 DG DN Art’s fast f/1.4 aperture makes it ideal for shooting in low light, achieving shallow depth of field, and providing ample background separation for portraiture. The rounded eleven-blade diaphragm helps produce large, pleasing bokeh. Using an APS-C sensor camera? You’ll have a focal length equivalent to 30mm.

Optimized for Astrophotography. In addition to its large maximum aperture, the 20mm f/1.4 has a range of features that make it a fantastic choice for astrophotography. Its optical design and in-camera corrections keep distortion reined in, producing extremely well-controlled sagittal flare that yields pin-point stars from edge to edge while limiting ghosting. A new Manual Focus Lock switch disables the focus ring so that your focus never changes even if you’re shooting under the night sky for hours. While this lens accepts 82mm front filters—itself a rarity on ultra-wide primes—it also includes a rear filter holder that accepts sheet-type filters that are often used by astrophotographers to produce various artistic effects.

Inner Focus Autofocus System. The 20mm’s autofocus system uses a stepping motor to provide fast, smooth, and nearly silent focusing for stills and video alike. You can also just rotate the focus ring at any point for manual-focus override. A built-in Autofocus-Lock button can be assigned additional functions, giving you more options and capabilities, while the above-mentioned Manual Focus Lock feature disables the focus ring entirely. This lens is compatible with select Sony E-mount cameras’ AF Assist function.

Advanced Optical Design. This lens’s fifteen-group/seventeen-element optical design includes three aspherical elements, two Special Low-Dispersion elements, and one concave double-sided aspherical element to minimize chromatic aberrations, distortion, and vignetting while providing maximum sharpness, color accuracy, and clarity. The elements have a Super Multilayer Coating that helps prevent flare and produce contrasty, color-neutral images, even when you’re shooting in backlit conditions.

High-Quality Build. The Sigma 20mm’s Thermally Stable Composite build is dust- and splash-resistant, so that you can use it in adverse conditions. It also boasts a brass bayonet mount for maximum durability. An included petal-type hood helps to prevent flare and protect the lens’s front element.