The Optics of Motion Picture Projectors

The usual method employed in designing an optical system seems to consist in assembling a collection of lenses and trying them in various combinations and positions until either the patience of the experimenter is exhausted or an optimum condition seems to be reached. This criticism does not apply, of course, to the optical systems of telescopes or microscopes, but rather to systems like that of the motion picture projector where it is relatively easy to obtain satisfactory definition in the image but difficult to secure enough illumination on the screen. Curiously enough, this unsystematic method of design procedure seems to be peculiar to optics, and is certainly due in part to a lack of knowledge concerning the performance that could be expected of an ideal optical system. In other branches of physics, such as heat, for example, there is the well-known and widely employed concept of thermal efficiency. Every heat engine or other piece of thermal equipment is rated by the closeness of its approach to the performance of an ideal apparatus which is assumed to operate without losses. In a previous paper, the present author has attempted to establish a similar basis of comparison for optical systems based on the conservation of energy principle. The purpose of the present paper is to apply the results to motion picture projectors.

Print ISSN

0097-5834

Published

1930-03

Content type

Original Research

DOI

10.5594/J13079