Posterior iris zoom lens

Abstract

Abstract PURPOSE: To obtain the zoom lens of good aberration characteristics by adding the specified conditions to the lens system consisting of the front group having negative refracting power and the rear group which has positive refracting power and whose iris is fixed in the outward rear direction which move in respectively the opposite directions on the optical axis. CONSTITUTION: The front group having negative refracting power consists of two negative lens and positive lens and the rear group having positive refracting power consists of three positive meniscus lens, negative lens and positive lens, wherein an iris is fixed in the rear part of the rear group. Selecting the focal length FA and radius of curavature r of the front group so as to satisfy formulas (1) thru (5) enables astigmatism and coma aberrations produced by the posterior iris to be corrected well together with other aberrations and enables the miniature two group zoom to be obtained. The incorporation of the posterio iris makes possible the use of the electron-controlled shutter. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Ryoichi Doi
• 👤 Yutaka Sakai
• 👤 Kazunori Ono

Bibliographic Details