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Proceedings Paper

Camera Viewfinder Using Tilted Concave Mirror Erecting Elements
Author(s): Donald DeJager
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Paper Abstract

The camera viewfinder would consist of a two-element objective lens, a field stop, a tilted concave mirror, an aperture stop, a second tilted concave mirror, and a two-element eyepiece. This forms a Z shaped configuration with the mirrors at the corners of the Z. The two mirrors, with the aperture stop midway between them, form a 1:1 telescopic erecting relay system. Two types of mirrors are studied: spherical and parabolic. The main problems encountered in the spherical mirror system are axial astigmatism and field tilt, both caused by the tilted mirrors. By using confocal, coaxial, decentered parabolic mirrors, with the aperture stop at the common focal point, the axial astigmatism can be eliminated; however, the field tilt problem is aggravated. By rotating the axis of the second parabolic mirror about the common focal point, the field tilt can be minimized, and the astigmatism in all beams eliminated. This last configuration is, however, plagued by distortion and coma. We conclude that none of these systems is satisfactory for image quality.

Paper Details

Date Published: 16 September 1980
PDF: 7 pages
Proc. SPIE 0237, 1980 International Lens Design Conference, (16 September 1980); doi: 10.1117/12.959096
Show Author Affiliations
Donald DeJager, Eastman Kodak Company (United States)

Published in SPIE Proceedings Vol. 0237:
1980 International Lens Design Conference
Robert E. Fischer, Editor(s)

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