Incidence height

Height of incidence in an optical image with a plano-convex lens ${\displaystyle H}$

In the case of optical imaging, the height of incidence is the distance between a light beam parallel to the optical axis . ${\displaystyle H}$

The back focal length of the refracted beam usually depends on the height of the entrance and therefore causes circles of confusion in the focal plane , which in some circumstances show up as errors in the image . The height of incidence and thus also such aperture errors can be limited by stopping down (see also critical aperture ).

In symmetrical systems, the entrance pupil is twice as large as the maximum height of incidence : ${\displaystyle D}$ ${\displaystyle H_{\mathrm {max} }}$

${\displaystyle D=2\cdot H_{\mathrm {max} }}$

literature

• Dietrich Kühlke: Optics. Basics and Applications. 2nd, revised and expanded edition. Harri Deutsch, Frankfurt am Main 2004, ISBN 3-8171-1741-8 , p. 94 (Chapter 2.5.1 Aperture errors (spherical aberration) ).