Zeiss Tessar

The name Tessar derived from the greek word tetra to indicate the typical four lenses scheme.

The Tessar is an evolution of the Cooke Triplet design in which the rear element is replaced by a cemented achromatic doublet.

A Tessar comprises four elements in three groups, one positive crown glass element on the front, one negative flint glass element at the center and a negative flint glass element cemented with a positive crown glass element at the rear.