Wide-angle lens system
AssigneePENTAX Corporation
InventorJun Hirakawa
Life of this patent
Estimating the term…
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AssigneePENTAX Corporation
InventorJun Hirakawa
Estimating the term…
A wide-angle lens system includes a negative first lens group, a negative second lens group, and a positive third lens group. The negative first lens group includes at least two negative meniscus lens elements each having the convex surface facing toward the object, and a positive lens element provided on the image-side of the two negative meniscus lens elements. The negative second lens group includes cemented lens elements and a negative meniscus lens element having the convex surface facing toward the object. The wide-angle lens system satisfies the following conditions: f2-3/f>1.6 (1) f3/f>1.5 (2) (f2-3/f)/(f3/f)>1.0 (3) wherein f2-3 designates the combined focal length of the negative second lens group and the positive third lens group; f designates the focal length of the entire wide-angle lens system; and f3 designates the focal length of the positive third lens group.
A wide-angle lens system comprising a negative first lens group, a negative second lens group, and a positive third lens group, in this order from an object,
Dependencies are inferred from the claim text.