Metrogon
From Wikipedia, the free encyclopedia
The Metrogon is an extra-wide field photographic lens used extensively by the US military for use in aerial photography. The design is by Bausch and Lomb based on the Topogon design by Zeiss. It is composed of two Gauss lenses with an extremely curved meniscus to provide a 90° field of view. The lens is symmetrical front to back. The two outer positive elements are of high index crown glass while the two inner negative elements are of a high index flint glass.
