In the mid-seventies, sales figures for Leica's rangefinder cameras had reached rock-bottom. Distribution numbers for the Leica M5 stagnated at around 6,000 units a year – not enough to warrant maintaining an entire factory plant. As a result, part of the camera production was relocated to Midland, Canada, based on financial considerations.
In response to these changes, Leica shifted their production focus from cameras to lenses, with the aim to re-invent the M series as Available Light reportage cameras. The focal length of 75 mm was deemed the optimal choice for this purpose.
The resulting Summilux 75 mm f/1.4 consisted of 7 elements divided into 5 groups – the essential framework of its optical construction was based on the Summilux 50 mm f/1.4 (II).
The production run of the Summilux 75 mm f/1.4 continued for almost 25 years (1980 to 2004), during which time around 13,000 units were sold.