GB855754A - Photographic objective - Google Patents

Abstract

855,754. Photographic objectives. ZEISSSTIFTUNG C., [trading as ZEISS, C. (Firm of)]. April 13, 1959 [July 5, 1958], No. 12373/59. Class 97(1) A photographic objective comprises on each side of a central air space three components of which the front and middle one of the three simple components to the front of this air space are convergent and the rear one of these components is a divergent meniscus simple lens while the middle and rear ones of the three components to the rear of this air space are convergent and the front one of these components is a divergent meniscus. This divergent meniscus is cemented to the simple convergent element next to it and the dispersive surfaces bounding the central air space have radii with numerical values lying between 0À25F and 0À65F. The divergent simple meniscus to the front of the air space has a thickness between 0À04F and 0À18F and a front surface having a radius between 0À35F and 0À65F. Further the distance between the front surface of the front component and the rear surface of this divergent meniscus is between 0À28F and 0À42F. Preferably the two surfaces having the strongest refractive power in the objective are separated by a distance between 0À5F and 0À85F and also between M and 1À6M where M is the arithmetical mean of the numerical values of the radii of these two surfaces. It is also preferred that the cemented doublet to the rear of the air space should have a thickness between 0À25F and 0À45F. Optical data are given for two embodiments of the objective shown, wherein the divergent and convergent components Liv, Lv are cemented together, and the surfaces of highest refractive power are r5 and r10.