GB795001A - Improvements in or relating to anamorphosing systems - Google Patents

Abstract

795,001. Optical systems. PANAVISION, Inc. Aug. 5, 1955 [Aug. 11, 1954], No. 22598/55. Class 97(1) A system particularly for motion picture photography or projection comprises, in optical alignment, an objective, an anamorphoser and an astigmatic device correcting any astigmatism in the combination of objectives and anamorphoser such as is introduced when the focusing of the objective is varied. As shown the anamorphoser 2U comprises two glass prisms arranged before the objective 30 and arranged to give a compression of the image in the horizontal plane when the object is focused for infinity. The astigmatism produced by the system 20 when the objective is focused on near objects is corrected by an astigmatic device 10 comprising a plano-cylindrical convex lens 12 and a plano-cylindrical concave lens 14 rotatable in opposite directions about the optical axis to vary the astigmatic effect produced thereby. The rotation may be effected by a gear 19 driven from a control member 50 which simultaneously adjusts the focus of the objective 30 by a gear 32 to set the astigmatic correction automatically to the object in focus. The lenses 12 and 14 may be of equal or unequal power or may be both positive or both negative.