An Art level 20mm f/1.4. The ultimate lens for astrophotography Highest optical performance on a new level Designed for perfect results even in the most demanding conditions Superb build quality and usability with uncompromising attention to detailOutstanding optical quality and a range of invaluable featuresThe ultimate astrophotography lens from the 20mm F1.4 pioneerThe F1.4 series represents the Sigma Art line, which pursues the highest optical performance and rich expression. The full-frame Sigma 20mm F1.4 Dg Dn | Art is a mirrorless version of the Sigma 20mm F1.4 Dg Hsm | Art the one and only lens with its unique specification of maximum aperture of 1.4 and an ultra-wide angle of 20mm. This lens offers photographers overwhelming optical performance and unlimited potential for ultra wide-angle creativity at a compact physical size.The exceptional F1.