The first version of the Summilux (7/5) is extremely rare and was only produced for fewer than two years before it was by an up dated second formulation.
It was Leica's first f1.4 "normal" and it was an extrapolated formulation of the F1.5 Schneider/LEITZ Sumarit, a modified double Gaussian formulation with four central cemented elements; it has a front singlet and a split rear element.
It was, however, a lens that people inside Leitz/Leica felt that had to be introduced since the international competition already had extremely credible offerings in this regime. The updated basic lens formulation dates back to the 1936 Schneider Xenon original double Gauss formula. It was an extended dimension reformulation with new glass technology. it had the shortest life span (two years) of any commercial Leica camera lens. Less than a total of 9,000 of the first version were produced including about 300 in screw mounts.
The second formulation,
two years later and a Canadian original design, is more worthy of the Leica product brand and lasted into into the 1990's. It is as if Leica did not want to acknowledge how egregious the original 50mm f1.4 is. Leica very quietly changed to the new (7/5) without any apparent lens body design changes or announcement for over five years until 1966. The second optical reformulation onsets with serial number 1,844,001 and weighs 360g, a full 35g more than the first.
Approximately in 1980, Leica updated the lens coatings with advanced multi coating technology improving effective contrast and overall transmissivity.
In 1995 the third optical version in a new physical mount was introduced:
The new optical formula is highly similar to the previous one but employs new glass formulations to very great advantage and according to Ghester Sartorius yields: "Outstanding optical results, excellent resolving power and contrast with unwanted reflections reduced." The new mount employs new materials and mechanics to great advantage and though it adds a built-in telescoping hood, it weighs almost 25% less than the previous version. The newer optical formulation permits focusing to 70cm (27in).
