| 摘要 |
923,634. Vari-focal objective. CARL ZEISSSTIFTUNG, [trading as CARL ZEISS, [Firm of]]. May 19, 1959 [Sept. 17, 1958], No. 16876/59. Class 97 (1). A variable focal length objective comprises a positive lens Group I, a negative lens Group II and positive and negative lens Groups III, IV. The focal length is varied by axial movement of lens Group II, the positive lens Groups I, III also being moved so as to maintain the image position in one plane. Preferably, the distance between the lens Groups I and III is maintained constant. Lens Group I may have an additional movement for forming on objects at different distances. French Specifications 1,112,979 and 1,120,271 are referred to. |
