Version I (circa 1953-62; serial numbers 1,459,000 - 1,650,000): Introduced in 1953 with the original DS M3 the original 90mm f2.0 Summicron the first optical formulation was produced until 1957 and sold by Leica as late as 1962. With 6 elements in five groups it appears very similar in design to and is a long focus recalculation of contemporaneous shorter focal length Summicrons.

Version II (circa 1963-80; serial numbers 1,651,000 - 3,013,000): This version is less than universally recognized; Dennis Laney, in his fine work "Leica Collectors Guide", lumps it together with the first version. Though the optical formulation appears very similar under casual observation; both versions are nearly symmetrical double Gaussian types with rearward of center pair cemented. Both are 6 elements in 5 groups; both versions are very similar in weight; but there are significant beneficial differences to the Midland Canada optimization of the original Wetzlar formulation. The new formulation employs new glass compositions, different lens element spacings, subtly altered glass/air interface curvatures and though it appears to be substantially the same lens, it performs very differently.

According to Erwin Puts: "...clear definition of coarse detail enhances the overall visual performance, compared to its predecessor. The lens is still sensitive to flare but less so. Finer detail is rendered with fuzzy edges, and gives the overall image a softer look...." ideal for a portrait lens.

Version III Summicron M (circa 1980- serial numbers 2,800,000 - 3,750,000): The third design is a complete departure. It bears more resemblance to the vintage 1970 Leica 90mm "R" Summicron and it is more of a telephoto in design than a long focus as were the previous designs. It is composed of a 3 group 4 element front set and a single element at the rear.