The Leica DG Nocticron 42.5mm f/1.2 ASPH. POWER O.I.S. is a fast portrait prime for Micro Four Thirds, giving an 85mm full-frame equivalent field of view at a maximum aperture of f/1.2 (aperture range f/1.2 to f/16). The optical design uses two aspherical elements plus one ED element and one Ultra High Refractive Index element, with Nano Surface Coating to suppress ghosting and flare. A stepping autofocus motor with internal focusing keeps focus fast and quiet, and POWER O.I.S. stabilises handheld shooting at the wide-open aperture. A manual aperture ring gives direct aperture control, and a rounded 9-blade diaphragm shapes background blur for portrait work on the Micro Four Thirds mount.