The Bell & Howell Cooke Varo Lens

A variable focus, variable magnification lens of new and outstanding design is described. The Varo is a “zoom” type lens, introducing the conception of a variable three-element system in place of the two-element variable telephoto system previously used for this type of work. A summary of the optical problems involved is presented, and a description of the lens showing how the mechanical design has been fitted to the optical specifications is given, together with a discussion of the relation of the rate of “zoom” to the loss of definition. The paper closes with a brief outline of the use of the lens in practice.

Print ISSN

0097-5834

Published

1932-10

Content type

Original Research

DOI

10.5594/J05480