In use 'single strokes' are generally much preferred, but some old timers are adamant that the 'double strokes' are smoother and even last longer because each stroke puts less stress on the gearing.ĩ19,251 (1958) Depth of field indicators placed in the Rangefinder. In terms of serial numbers here is a guide from Cameraquestħ85,801 (1955) added Viewfinder Frame Selector LeverĨ44,001 (1957) glass film pressure plate changed to metalĩ19,251 (1958) Lever advance changed from two to single stroke. There are many variants of M3s as there were changes made as new technology developed.
