Rare Leica M6 “electronic“ prototype with typical serial number 1234567 in nice condition with functional shutter (/100), complete with prototype motor drive no. 00008 and extremely rare Leica prototype lens Elmarit - M 28mm f/2.8 with built-in sunshade, of which only two examples are known to exist. Lens with clean optics and prototype number 5001632. By end of the 1970s it was one of the most important challenges for the Leitz designers, to integrate a TTL metering into the Leica M camera. Leitz designer Peter Loseries had the idea of using the Leica R4 with its Seiko shutter as a basis. Mirror box and pentaprism were taken off and instead a rangefinder was added on top. The result was a Leica M with TTL metering, optional automatic exposure and a large camera rear door opening horizontally. The R4 data back, as well as winder and drive were compatible. What sounds so simple, in fact was almost an entirely new design. For various reasons this camera never went into commercial production. Only a few complete sample units do exist.