GB1020462A - - Google Patents

Abstract

1,020,462. Photographic objectives. CARL ZEISS-SHIFTUNG [trading as CARL-ZEISS]. April 17,1964 [April 20,1963; June 26,1963], No. 16095/64. Heading G2J. The objective consists of eight lenses arranged as six members characterized by:- (a) the front member is a meniscus concave to the second member and consists of two cemented lenses L I , L II of opposite refracting power wherein the refractive index n s of the positive lens and n z of the negative one satisfying the Abbey number v s of the positive lens and v z of the negative lens satisfying the sum of the refractive powers of the surfaces of the front member lie within the limits (b) the second member is a meniscus positive lens convex to the front member (c) the third member is a meniscus negative lens concave to the stop (d) the aperture stop is between the third and fourth members (e) the fourth member is a meniscus negative lens concave to the stop and consists of two cemented lenses of opposite refractive powers the glass of the negative lens having a greater chromatic dispersion than the glass of the positive lens (f) the fifth member is an asymmetrical positive lens having the refractive power b v of its front surface and b h of its rear surface satisfying (g) the sixth member is a positive lens Numerical data are provided for the example shown wherein the front member has positive refractive power and also for a second example, Fig. 2, (not shown) in which the front member has negative refractive power.