Sigma 20mm F1.4 DG HSM | Art (L-Mount)

The 20mm F1.4 DG HSM was the world's first 20mm f/1.4 for full frame, launched for DSLRs and later offered in a native L-Mount version. Its key part is a 59mm double-sided aspherical element at the front, backed by two FLD and five SLD elements to keep lateral colour down. It suits night landscapes, astro and dim interiors.

The L-Mount version keeps the SLR optics and extends the barrel to cover the flange difference, so it is 153.75mm long and weighs 1,035g. The bulbous front element sits behind a built-in hood, so there is no screw-in filter thread, and focus is driven by an HSM ring motor with manual override. Sigma now lists the L-Mount version as discontinued, replaced in practice by the much smaller 20mm F1.4 DG DN.