Photographic lens system
AssigneeOlympus Optical Co., Ltd.
InventorsToshihiro Imai, Hiroshi Takase
Life of this patent
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Abstract
A photographic lens system is constituted of four lens components and four lens elements, comprising a first lens component of a meniscus positive lens with its convex surface on the object side, a second lens component of a biconcave lens, a third lens component of a biconvex lens and a fourth lens component of a meniscus negative lens with its convex on the image side. It is so arranged that the shortening of the focal length in such a manner that the image quality is kept good over a wide angle of field of view and the reducing of the telephoto ratio are well balanced so as to enable provision of a very compact photographic lens system having superior characteristics.
Claims6
A photographic lens system comprising a first lens component of a meniscus positive lens with its convex surface on the object side, a second lens component of a biconcave lens, a third lens component of a biconvex lens and a fourth lens component of a meniscus negative lens with its convex surface on the image side, the said lens system satisfying the following conditions:
- 1.5<f/f.sub.123 <1.7 (1)
- -1.3<f/f.sub.4 <-1.0 (2)
- 0.07<d.sub.5 f<0.11 (3)
- 0.14<d.sub.6 /f<0.19 (4)
- wherein the reference symbol f represents the focal length of the total lens system, the symbol f.sub.123 represents the composite focal length of the first, second and third lens components, the symbol f.sub.4 represents the focal length of the fourth lens component, the symbol d.sub.5 represents the axial thickness of the third lens component and the symbol d.sub.6 represents the axial air space between the third and fourth lens components, respectively.
Dependencies are inferred from the claim text.