| 摘要 |
PURPOSE:To correct satisfactorily various aberrations extending over the whole displacement area of zooming by constituting so that an optical system consisting of three lens groups having refractive powers of positive, negative and positive in order from an object side satisfies prescribed conditions. CONSTITUTION:A relay lens system consists of a front group containing positive and negative lens components, and a rear group containing negative convex meniscus and positive biconvex lens components at an image side, and the first group contains two positive lens components and one is a stuck component, the second group contains two negative components and one is a stuck component, and the third group contains at least one positive lens component. This optical system is made to satisfy each condition of an expression I - an expression IV. In this regard, in the expressions, fR denotes a composite focal distance of the relay lens system, ra, rb denote radiuses of curvature of surfaces of an object side and an image side of a negative meniscus lens which is convex to the image side of the rear group of the relay lens system, f1, f2 denote focal distances of the first and the second groups, respectively and rc, rd denote radiuses of curvature of surfaces of the object side and the image side of the negative lens component of the object side of the second group, respectively. |
