In the late seventies, Leitz explored the idea of providing the Available-Light fans among M photographers with a high-speed telephoto lens. However, it soon transpired that the targeted speed of f/1.4 could not be realised within a 90 mm focal length – the lens would have become so large that it would have blocked much of the viewfinder.
For this reason, the focal length of 75 mm was introduced into the M system. What may have begun as a compromise soon proved to be anything but: better at drawing the eye towards the main subject than a 50 mm, while offering a more understated tele-effect than a 90 mm, the new focal length soon became the standard-selection of choice for many M photographers.
In 2004, Leica achieved great success with their Apo-Summicron M 75 mm f/2 Asph. The small tele lens combines high light sensitivity with consistently excellent quality across the entire image plane, while still offering a very compact design.