The forerunner of the Summilux-M 50 mm f/1.4 – which bore the same name – was only part of the Leitz product line for two years, while the version that first appeared in 1961 was produced for 40 years – a record still unsurpassed today.
The fact that it remained in the range for so long proves that Leitz had come up with a first class design. At full aperture its contrast performance was relatively good, at least in the centre of the image, so that for a long time it alone set the standard for high-speed 50 mm lenses.
At the same time, this shows how complex it is to significantly improve spherical aberrations, in a challenge setting like an aperture ratio of 1:1.4. When the Summilux was conceived, Leitz was able to take advantage of computers for reducing optical aberrations – in fact, the company pioneered in this area.
However, in certain respects – as in the case of close-up performance – it continued to be a compromise, albeit at a very high level. The decisive break-through that finally made new computations worthwhile, came with the perfecting of asphere technology as of the nineteen nineties.