The Sigma 20mm f/1.8 EX DG ASPHERICAL RF is a wide-angle lens designed for Canon EF mount cameras, suitable for both full-frame and APS-C sensors. Its bright f/1.8 maximum aperture allows you to capture images in low-light conditions and achieve a shallow depth of field, while the 82mm filter thread provides compatibility with a wide range of professional filters. Constructed in a black finish, this lens weighs 520 g and measures 89.5 mm in length with a diameter of 88.6 mm. It features a dual focus mechanism with a manual/auto focus clutch for quick transitions between focusing modes, complemented by an integrated aperture ring, distance scale, and depth of field scale to help you maintain precise control over your shots. This setup is well-suited for landscape and architectural photographers who need a wide perspective without sacrificing light intake, and it comes bundled with a lens hood and a protective pouch.