GB1259086A - - Google Patents

Abstract

1,259,086. Photographic objective. CARL ZEISS JENA VEB. Feb.13, 1970, No.6977/70. Heading G2J. A five-component lens of the modified Gauss type has a relative aperture of 1:1À8 and an image angle of 46 degrees, the distance between the lens vertex and image being greater than 0À72 times the entire focal length, and consists of six elements as follows, a dispersive element IV on the image side of a diaphragm, a dispersive component on the object side of the diaphragm made up of a biconvex element II and a biconcave element III cemented together, the stronger race of elements III and IV facing the diaphragm, and the lens half on the image side of the diaphragm further consisting of a converging meniscus V and biconvex VI elements, the lens half on the object side of the diaphragm further consisting of a converging meniscus element I, the following conditions applying: - 1) The air-space 1 3 separating elements IV and V has a thickness of between 0À028 and 0À048 F, and a dispersing effect which is greater than 5% but less than 20% that of element IV 2) The sum of the absolute values of the radii (r 3 , r 5 , r 6 , r 9 )>1À5F but <1À8F 3) The difference of the refractive indices of elements II and III for #=587À6nm is between 0À07 and 0À09; the differences of their Abbe numbers is between 18 and 22, and the difference between the Abbe numbers of elements V and IV is between 21 and 25. Optical data is given for one example.