| 摘要 |
PURPOSE:To realize a zoom lens of four-group type which has about six-time zooming ratio, it bright with F1:1.2 aperture ratio and has high performance by constituting the IV-th lens group of six elements, positive, negative, positive, negative and positive from the object side as a relay lens part and satisfying the specific condition equations. CONSTITUTION:This lens is constituted of six-groups six-elements in which the 1st lens group consists, from an object side, of a negative meniscus lens, positive lens and positive lens, the II-nd lens group consists, from the object side, of a negative meniscus lens and a combined lens of a biconcave lens and a positive lens convex on the object side, the III-rd lens groups consists simply of a single negative lens concave on the object side and the IV-th lens group consists, from the object side, of a positive lens having the image side face convex on the image side and large curvature, positive lens having the object side face convex on the object side and large curvature, negative lens having the object side concave on the object side and large curvature, positive lens having the object side face convex on the object side and large curvature, negative lens having the image side face concave on the image side and large curvature and biconvex positive lens. The lens is so constituted as to satisfy the nine condition equations. |
