Compact zoom lens

Abstract

Abstract PURPOSE:To reduce the variation of an aberration in the course of variable power, and to set a zoom ratio to about two, by forming the front group and the rear group by a negative lens and a positive lens, and a positive lens and a negative lens, respectively, in a lens system which consists of the front group having positive refracting power and the rear group having negative refracting power in order from an object side, and executes variable power by changing an interval between the front group and the rear group. CONSTITUTION:The titled zoom lens is constituted of the front group F and the rear group R in order from an object side, and the front group F consists of a first lens being a concave meniscus lens whose convex surface is turned to the object side, and a second lens being a biconvex lens. The rear group R consists of a third lens being a convex meniscus lens whose concave surface is turned to the object side and a fourth lens being concave meniscus lens whose concave surface is turned to the object side. Also, this zoom lens is a two-group zoom lens in which the front group F and the rear group R move in the course of variable power and a group interval decreases extending from the wide angle end to the telephoto end. In such a way, although the number of lens pieces is four pieces, various aberrations are corrected enough, and even in the course of variable power, the aberration is scarcely varied, a zoom ratio is about two times, and a compact lens system having a large aperture ratio is obtained.

Inventors

• 👤 Norihiko Aoki
• 👤 青木　法彦

Bibliographic Details