The Sigma 20mm f/1.4 DG DN Art Lens offers incredible imaging performance from corner to corner, with a large maximum aperture that makes it ideal for use in low-light environments, particularly under dark skies where its new features are especially useful. Additionally, a new Manual Focus Lock (MFL) switch disables the focus ring, ensuring that focus never changes, even after hours of shooting under chilly, dark skies. The lens has also been developed to accept 82mm front filters, a rarity on ultrawide primes, and another unique feature that includes a rear filter holder, which accommodates sheet filters for various creative effects. Prime wide-angle 20mm f/1.4 lens is designed for full-frame format Sony E-mount mirrorless cameras and can also be used with APS-C models where it provides a 30mm equivalent focal length. Two SLD and three aspherical elements have been incorporated within the lens design to correct for chromatic aberrations throughout the entire focusing range and to ensure exceptional clarity and contrast. This optical design also helps to control distortion and limit vignetting. A Super Multilayer Coating has been applied to lens elements to minimize lens flare while producing contrast-rich and color-neutral imagery, even in backlit conditions. Optimized for astrophotography, a new MFL (Manual Focus Lock) switch disables the focus ring, ensuring that focus never changes, even after hours of shooting under chilly, dark skies.A petal-shaped lens hood helps to reduce lens flare when working in strong lighting conditions and offers some protection to the front element of the lens.