| 摘要 |
932,950. Photographic objectives. CARL ZEISS STIFTUNG, [trading as C. ZEISS, [firm of]] Dec. 15, 1959 [Jan. 21, 1959], No. 42620/59. Class 97 (1). A photographic objective of the kind having five simple lenses, an angle of field of about Œ16 degrees, a backfocal length less than the equivalent focal length and an iris diaphragm positioned between the fourth and the fifth lenses at a point which is distant from the rear focal point between 0.5F and 0.7F, is characterized in that the first lens L 1 is a dispersive meniscus concave towards the diaphragm, the second lens L II is a collective meniscus concave towards the diaphragm, the third lens L III is an asymmetrical collective lens having its more deeply curved surface convex towards the second lens, the fourth L IV is an asymmetrical dispersive lens having its more deeply curved surface concave towards the diaphragm, the fifth lens L v is a meniscus-shaped collective lens concave towards the rear, and the v-value of the first lens Ll is less than that of the second lens L II . Preferably, the first and second lenses are cemented together, as also are the third and fourth lenses. Optical data are given for one embodiment of the objective illustrated in which the lenses L I , L II and the lenses L III , L IV are cemented together. |
