THREE-LENS SYSTEM PROVIDING A VARIABLE FOCAL POWER ALONG ONE PRINCIPAL MERIDIAN

摘要

THREE-LENS SYSTEM PROVIDING A VARIABLE FOCAL POWER ALONG ONE PRINCIPAL MERIDIAN Variable focal power along one principal meridian may be obtained by an optical system having two cylinder lenses at either end and their axis of cylinder in a single plans spaced along an optical axis. A moveable cylinder lens with its axis oriented 90.degree. to the plane is slideably mounted therebetween. A plano color correction plats substantially eliminates color aberrations which would otherwise be present in the system.