The Design of Photographic Objectives of the Triplet Family. II. The Initial Design of Compound Triplet Systems

Abstract

Part II. The general method developed for the type 111 triplet is extended to the initial design of triplet systems having compound components. The possibility of replacing a single lens by an equivalent doublet or triplet allows the single lens to be regarded as not being restricted to values of N and V associated with known glass types. It follows that the glass parameters oc, ~, y, and ~ may be treated as continuously variable over limited ranges. The general effects of the variation of these parameters on the powers and separations of the basic initial solutions are shown in a set of diagrams. As an example, the initial design of a triplet with compound members is given in detail.