The Leica Summaron 35mm f/3.5 is a vintage classic wide-angle rangefinder lens produced by Ernst Leitz GmbH from 1946 to 1960.While initially made in Leica Thread Mount (LTM/M39), a native Leica M-mount version was introduced around 1956, sometimes available with “goggles” designed specifically to correct the 50mm viewfinder framelines on early Leica M3 bodies to a 35mm field of view.