GB933437A - Photographic objective - Google Patents

Abstract

933,437. Photographic objectives. CARL ZEISS-STIFTUNG, [trading as C. ZEISS, [Firm of]]. Oct. 5, 1959 [Oct. 10, 1958], No. 33736/59. Class 97 (1). A photographic objective comprises two simple collective components L I , L VII enclosing two dispersive components located on opposite sides of a diaphragm. The front one of these components is a simple lens L II , while the rear one comprises two elements L v and L VI which are cemented together or are in broken contact. The adjacent surfaces of these two components are inwardly concave and have radii between 0.18F and 0.4F and are axially separated by a distance greater than the arithmetical mean of the radii R4 and R8 but less than twice the arithmetical mean. Between these dispersive components is a dispersive meniscus doublet L III , L IV which is concave towards the rear and consists of a convergent lens L III and a dispersive lens L IV . The surface R7 is concave towards the diaphragm and has a radius between 0.5F and 2F, and lens L IV has an Abbe number less than that of the lens L III . The cemented surface R6 is convex towards the rear. Preferably, the difference of radii of the surfaces R5 and R7 lies within the limits 0.2F and 2.5F. Optical data are given for one example of the objective shown.