Leica APO-Summicron 50mm ASPH (mislabelled Zeiss), widely considered the finest 50mm lens ever produced.
The Leica APO-Summicron-M 50mm f/2 ASPH is the current-production ultra-premium standard prime for the Leica M mount — APO = apochromatic, ASPH = aspherical. One of the finest 50mm lenses made. Note: canonical name has erroneous 'Zeiss' prefix. Leica M mount.
f/2 maximum aperture. 50mm focal length (full-frame standard prime). Apochromatic. ASPH element. Rangefinder-coupled. At approximately 320g. Leica M mount.
The APO-Summicron-M 50mm f/2 ASPH achieves near-perfect correction including apochromatic colour correction — essentially no lateral chromatic aberration at any aperture. A benchmark lens widely regarded as technically supreme at 50mm. Commands a significant price premium.
On the used market the Leica APO-Summicron-M 50mm f/2 ASPH is a premium lens commanding a high premium. Condition checks: front element, rangefinder coupling. Leica M mount.