This all-new full-frame premium compact prime for mirrorless systems is the latest addition to Sigma's I series lineup, combining a bright maximum aperture of F2, an ultra-wide 20mm focal length and stunning optical performance. The lens boasts an exceptionally small form factor, weighing in at just 370g and measuring just 72.4mm in length, which makes it a highly practical optic that is portable enough for everyday shooting.It's ideal for landscapes, wide-angle portraits, weddings and interiors, and is particularly well-suited to astrophotography owing to its very well-controlled sagittal coma flare. It is the fourth I series lens with an F2 aperture, joining a 24mm, 35mm and 65mm, which together make a well-matched lens set for L-Mount and Sony E-mount users.Remarkably, the 20mm F2 Dg Dn | Contemporary is almost identical in size and weight to the very compact Sigma 24mm F2 I series.