Stabilization of pupils in a zoom lens with two independent movements.

A procedure for thin lens structural design of a new class of pupil stabilized zoom systems is presented. This is facilitated by an implementation of evolutionary programming that searches a multivariate hyperspace formed by design variables, namely, powers of individual components and intercomponent separations. Two coupled components in the lens system act as the variator for the zoom system, and another component in the system acts as the compensator. A fixed axial location of the image plane is achieved by moving the coupled variator and the compensator nonlinearly, while the entrance and the exit pupils are allowed small shifts in their axial locations over the zooming range. The latter relaxation opens up the possibility for effective two-conjugate zoom systems with only two independent component movements. Illustrative examples for thin lens structures of two-conjugate zoom systems are presented.