Astigmatism.

A monochromatic Seidel aberration which causes focus problems in objects located away from the optical axis of the lens. Lenses with astigmatism have different effective focal lengths for rays of light entering off-centre. In human eyes astigmatism is caused by the cornea being unevenly curved.

cf. aberration, lens, Seidel aberrations.

Entry last updated 2002-05-08. Term 84 of 1487.

Previous term: aspherical.

Next term: astrophotography.

 

This document is copyright © 2002-2008 NK Guy, PhotoNotes.org. This information is provided with neither warranties nor claims of accuracy or completeness of any sort. Use this information at your own risk. All trademarks mentioned herein belong to their respective owners.

You may copy and print this document for your own personal use. You may not, however, reprint or republish this work, in whole or in part, without prior permission from me, the author. Such republication includes inclusion of this work in other Web sites, Web pages, FTP archives, books, magazines or other periodicals, CD-ROM and DVD-ROM compilations or any other form of publication or distribution. Please do not frame this site within another.

Please send comments or error reports using the feedback form.