Summicron 2/35mm 11309 Thorium for US Military *
Startpreis
6.000 €
Gebote: 0
12.000 – 14.000 €
Versandnformation
As early as 1952/53, Leica began developing advanced optical coatings and special glass formulations, including elements enriched with thorium oxide (ThO₂). This so-called thorium glass offered excellent optical properties, such as a high refractive index and low dispersion, but also exhibits slight natural radioactivity.
By the late 1960s and early 1970s, the use and manufacture of thorium-containing glass were completely discontinued in Germany and much of Europe due to new regulations. From that point onward, the production of optical glass containing thorium oxide was no longer permitted, affecting not only photographic optics but also other precision industries.
In 1972/73, in connection with the later-legendary KE-7A project, Leica received a request from the U.S. Government to develop a special lens incorporating thorium glass. As such production was already prohibited in Germany, even for special commissions, the development and manufacture were transferred to Ernst Leitz Canada (ELCAN).
Although the project never entered series production, several fully functional prototype lenses were produced for testing and evaluation. One of these extremely rare prototypes is offered in the present auction. Preserved in very good original condition, the lens shows the characteristic slight yellowing associated with thorium glass.
An exceptionally rare and historically significant Leica prototype, representing a unique military and governmental special development and an important collector’s item.