The blue bundle of rays does the same thing, converging at the blue circle.
The green bundle of rays sees the same feature, but as viewed from the bottom edge of the camera's aperture.
First we derive aberration functions of Seidel and Buchdahl types for a bundle of rays converging to dispersed Gaussian images.
It is easy to imagine representing a narrow beam of light by a collection of parallel arrows a bundle of rays.
If you follow the red bundle of rays in the applet, they start (at left) in the scene, pass through the top of the main lens, and are focused by Micro Lens 1 onto CCD 1.
As the beam of light moves from one medium to another, reflects off surfaces, disperses, or comes to a focus, the bundle of rays traces the beam's progress in a simple geometrical manner.
Modern studies of this subject employ a contact lens fitting on to the globe; on the lens is a small plane mirror, and a parallel bundle of rays is reflected off this mirror onto a moving film.
The principal and focal points may be defined as follows: Figure 5 shows a lens system of any construction, with a bundle of rays entering from the left in a direction parallel to the lens axis.
If you follow the red bundle of rays in the applet, they start at an unseen object lying on the optical axis (black horizontal line) to the left of the applet, pass through the main lens, and reconverge on the optical axis.
The red bundle of rays start from the in-focus plane on the left edge of the applet, diverge for a while, pass through the green lens (remember that we're ignoring the close-up filter), then bend and follow the green lines, reconverging at the red circle on the sensor (vertical gray bar).
