Leica APO-Summicron-SL 90 f/2 ASPH.

The 90mm is the classic portrait focal length of the APO-Summicron-SL pair, launched alongside the 75mm and built to the same 102mm x 73mm barrel with a 67mm filter thread. Its eleven elements in nine groups include one aspherical element, and most are made of glass with anomalous partial dispersion for apochromatic correction, so colour fringing on high-contrast edges is kept to a minimum.

Autofocus is driven by stepping motors with Leica's Dual Syncro Drive, which Leica rates at around 250 milliseconds across the whole focus range. Close focus is 0.6m for a 1:5 reproduction ratio. The metal housing is sealed against dust and splash water, weighs 700g and has no switches on the barrel; aperture and focus mode are set on the camera.