Zoom lens system
AssigneeHoya Corporation
InventorsToshiki Nakamura, Takayuki Ito
Life of this patent
Estimating the term…
Loading patent…
AssigneeHoya Corporation
InventorsToshiki Nakamura, Takayuki Ito
Estimating the term…
A zoom lens system includes a negative first lens group, a positive second lens group, and a positive third lens group functioning as a focusing lens group, in this order from the object. Upon zooming from the short focal length extremity to the long focal length extremity, the distance between the negative first lens group and the positive second lens group decreases, and the distance between the positive second lens group and the positive third lens group increases. The positive third lens group includes cemented lens elements having a positive lens element and a negative lens element. The zoom lens system satisfies the following condition: 0.2<f3−p/|f3−n|<0.35 (1) wherein f3−pdesignates the focal length of the positive lens element of the positive third lens group; and f3−ndesignates the focal length of the negative lens element of the positive third lens group.
A zoom lens system comprises a negative first lens group, a positive second lens group and a positive third lens group functioning as a focusing lens group, in this order from an object,
Dependencies are inferred from the claim text.