principal ray

In ray tracing, a ray traveling from an off-axis point in the field of view and directly through both principal points, appearing to pass straight through the center of a lens undeviated.

Related MicroscopyU Article

Geometrical Construction of Ray Diagrams

A popular method of representing a train of propagating light waves involves the application of geometrical optics to determine the size and location of images formed by a lens or multi-lens system. This tutorial explores how two representative light rays can establish the parameters of an imaging scenario.