Leica Summitar 50mm f/2 (1939-1953)

This lens replaced Summar f/2.0  in 1939 and was later superceded by Summicron 50 f/2.0 in 1959. It's compact collapsible design and reputed having extreme center sharpness which softens towards the corners.  The specimen I have is a screwmount, attached to L39 to M adapter then mounted to the Sony A7S via a Metabones Leica M to Sony E adapter.

Cropped

Cropped

Cropped

Cropped, at f/2.8

Cropped, at f/5.6

Cropped, at f/11.0