The Summicron-M 50 mm f/2 (IV) was first introduced in 1979. The fact that it is still on the market today firmly proves its outstanding quality. While the contrast rendition is similar to that of its predecessor, the most distinguishing improvement is the lens' detail resolution, resulting in bright, crisp images. Even after almost 35 years on the market, the Summicron-M 50 mm f/2 (IV) still represents a qualitative benchmark against which new lenses must be measured.
The fourth-generation 50 mm Summicron also differed from its predecessor in terms of its optical construction. The new design was rooted in the doctoral dissertation of Canadian Leica engineer Walter Mandler, which explored the concept of the Double Gauss lens.
The glass types used in the Summicron incidentally also made it possible to produce the Noctilux without aspherical elements.