GB927898A - Photographic objective - Google Patents

Abstract

927,898. Photographic objectives. CARL ZEISSSTIFTUNG, [trading as C. ZEISS Firm of]]. Oct. 8, 1959 [Oct. 10, 1958], No. 34206/59. Class 97 (1). A photographic objective for taking or reproduction consists of six lenses of which the first and the second each have collective refractive power, the third and the fourth each have dispersive power and the fifth and the sixth each have collective refractive power, the second lens and third lens being cemented to each other and all surfaces having a radius of curvature smaller than the equivalent focal length of the objective being concave towards a diaphragm placed between the third lens and the fourth lens, is characterized in that the following conditions are simultaneously satisfied: 1. 0.50.f < D s < 0,60.f 2. 1,20.rs < D s < 1,65.#r s 3. 0,35.f < #r s < 0,45. f 4. 0,22.f < D z < 0,33.f 5. 0,90.r z < D z < 1,10.r 2 6. 0,22. f < #r z < 0,33. f 7. 0,70. f < B < 0,80.f 8. 3,30 < n III +n v < 2.n IV 9. 1,80.#r z < D 8 < 2,2.#r z 10. 1,00.r 5 < |r 6 | < 1,40.r 5 11. 0,002. f < d 7 < 0,022.f 12. 0.08.f < d 3 + d 4 < 0.92.f 13. 0,08.f < d 6 + d 7 + d 8 < 0,20.f 14. 0,20.f < r 5 < 0,28.f 15. 0,26.f < |r 6 | < 0,33.f 16. 0,24. f < D s -d z < 0,30.f wherein the symbols have the following meanings: f = the focal length of the objective r s ¢ À(r 3 + | r 9 |) D s = the apical separation between surface 3 and surface 9 #r z ¢ À (r 5 + |r 6 |) D z = d 5 = the length of the diaphragm space B = the overall length of the objective d 3 = the axial separation between surface 3 and surface 4 d 4 = the axial separation between surface 4 and surface 5 d 6 = the axial separation between surface 6 and surface 7 d 7 = the axial separation between surface 7 and surface 8 d 8 = the axial separation between surface 8 and surface 9. Optical data are given for an example of the objective shown.