Zoom lens
AssigneeCanon Kabushiki Kaisha
InventorKazuo Tanaka
Life of this patent
Estimating the term…
Abstract
A zoom lens comprises, in succession from the object side to the image side, a positive first lens group movable for focusing, a negative second lens group movable for zooming, a positive third lens group movable for zooming, a negative fourth lens group movable for zooming and moved with the second lens group, and a stationary fifth lens group. When .beta..sub.i is the lateral magnification of the ith lens group as counted from the object side, the lateral magnification of each of the lens groups satisfies at a point in zooming .beta..sub.2 <0, .beta..sub.4 <0, .beta..sub.2 .beta..sub.4 =1, .beta..sub.3 =-1 and satisfies at the point -1.3<.beta..sub.2 <-1.025.
Claims3
A zoom lens comprising, in succession from the object side to the image side, a positive first lens group movable for focusing, a negative second lens group movable for zooming, a positive third lens group movable for zooming, a negative fourth lens group movable for zooming and moved with said second lens group, and a stationary fifth lens group, and wherein when .beta..sub.i is the lateral magnification of the ith lens group as counted from the object side, the lateral magnification of each of said lens groups satisfies at a point in zooming of zooming integral curves
- .beta..sub.2 <0, .beta..sub.4 <0, .beta..sub.2 .beta..sub.4 =1, .beta..sub.3 =-1
- and satisfies at said point
- -1.3<.beta..sub.2 <-1.025.
Dependencies are inferred from the claim text.