Originally Posted By: ellenbr
...
Before WWII(beginning in Jena in 1846) Zeiss had facilities in Oberkochen and Jena. In the late 1880s, Jena Glass was used in Voigtlander photo systems and was probably the beginning of quality optics in sporting optics. The key in optics is light transmission and the discovery of adding an ar coating was the beginning of great advances of optics. Before WWII in the 1930s, an ar coating was added which lead to the mark of the Red "T" on Zeiss optics. I've read that advances in ar coatings were post WWII but also that a patent circa 1936 yielding the "T*" mark on Zeiss optics.
...


There are several "keys" in regard to lens development. Just a few that relate to what you mention.
1. Development of a true vacuum
2. Development of powdered metals
3. Determining the effect of a coating on a particular wavelength given the charisterics of the glass.

Here is a Zeiss copyright for producing metal powders.
http://www.google.com/patents?id=qqNcAAA...1960&num=50

Another Zeiss copyright for an improvement in vacuum technology.
http://www.google.com/patents?id=CgJbAAA...1960&num=50

The last piece had depended on a good optical bench. Today computer models make the determinations for lens design. The designer inputs the requirements of the lens and the computer determines the glass, coatings and grinding.

When they started using various marketing tactics such as a Red "T", I do not know.

Pete
Damascus-Barrels