| 摘要 |
PROBLEM TO BE SOLVED: To provide a small-size wide-angle lens with a large aperture which is suitable for a photographing lens of a compact camera, which has first to fourth lenses components with negative, positive, positive and negative powers from the object side, respectively, which has a Y/f larger than 0.77, the F<SB>NO</SB>smaller than 2.8, and which has a compact configuration with a number of lenses as small as 6 or 7, a small lens diameter and a short back focus, but high performance, and to provide a camera equipped with the above lens. SOLUTION: The lens includes, from the object side, a first lens component I having negative refractive power and comprising a concave lens with a concave face opposing the object side, a second lens component II having positive refractive power and comprising a joined lens of a dual convex lens and a concave lens, a diaphragm, a third lens component III having positive refractive power and comprising a concave lens with an aspheric surface where the power of the concave increases to the periphery and a convex meniscus lens with a convex face opposing the image side, and a fourth lens component IV having negative refractive power and comprising a concave lens with an aspheric surface where the concave power decreases to the periphery and an aspheric surface where the convex power increases to the periphery, and a concave lens with a concave face opposing to the object side. The small-size wide angle lens with a large aperture satisfies conditions such as (1) 1.7<F<SB>NO</SB><2.8, (2) 0.77<Y/f<1.1, (3) -2<f<SB>1</SB>/f<-0.95 and (4) -1.1<f<SB>4</SB>/f<-0.7. COPYRIGHT: (C)2006,JPO&NCIPI
|
