[Skip to Content]
[Skip to Content Landing]
Article
September 1939

A MEMORY SCHEME FOR THE CARDINAL POINTS

Arch Ophthalmol. 1939;22(3):448-449. doi:10.1001/archopht.1939.00860090114014

This article is only available in the PDF format. Download the PDF to view the article, as well as its associated figures and tables.

Abstract

Every optical system has six important points, called cardinal points, associated with, and inherent in, the system. These are two principal focal points, F1 and F2, two principal points, P1 and P2, and two nodal points, N1 and N2. In the simplest optical system, such as a curved spherical mirror, these six cardinal points are reduced to three, as each pair of points coincide; i. e., F1 coincides with F2, P1 with P2 and N1 with N2. In a slightly more complex optical system, such as a single refracting surface, the six cardinal points are reduced to four, as two pairs of points coincide, i. e., P1 with P2 and N1 with N2. In a lens situated in air, the six cardinal points also are reduced to four but by a different kind of coincidence.

First Page Preview View Large
First page PDF preview
First page PDF preview
×