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Proceedings Paper

An Improved Zoom Lens With External Entrance Pupil
Author(s): Karl M. Bystricky; Paul R. Yoder
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Paper Abstract

In order to minimize the overall length and diameter of a zoom objective system with non-trivial magnification change, when the entrance pupil must be located in front of the first element, an intermediate image should be formed, a field lens located at or near that image, and a zoom relay used to produce the focal length change. Usually such lens systems compensate image shift by moving all or part of the front element or by dividing the zoom relay into two independently moving parts. In this paper we describe an improved approach in which the tasks of focal length change and image shift compensation are shared by movements of the field lens and of the relay. This facilitates the optical design, allows the internal pupil to be favorably located, creates the possibility of fixing the exit pupil in size and position, reduces the overall size of the system, and allows a more favorable optical and mechanical design of the compensating parts. The advantages of the new concept are discussed, thin lens examples given, and potential applications to specific types of instruments suggested.

Paper Details

Date Published: 1 March 1974
PDF: 6 pages
Proc. SPIE 0039, Applications of Geometrical Optics II, (1 March 1974); doi: 10.1117/12.953797
Show Author Affiliations
Karl M. Bystricky, The Perkin-Elmer Corporation (United States)
Paul R. Yoder, The Perkin-Elmer Corporation (United States)

Published in SPIE Proceedings Vol. 0039:
Applications of Geometrical Optics II
Warren J. Smith, Editor(s)

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