| 摘要 |
A wide angle lens (100) has a first lens (1), a second lens (2), a third lens (3), and an aperture (4) which are arranged in that order from the object side. The first lens (1) has negative power and is a spherical meniscus lens having a convex surface facing the object side. The second lens (2) has negative power on the optical axis, with the lens power turning from negative to positive farther off the optical axis, and is an aspheric meniscus lens having a convex surface facing the object side. The third lens (3) is a lens having positive power. The Abbe number of the second lens (2) is 30 or less. The ratio between the diagonal length D of an imaging element mounted on the image forming surface of a lens system and the focal length f of the entire lens system satisfies f/D = 0.26, and the ratio between the focal length f3 of the third lens (3) and the focal length f of the entire lens system satisfies f3/f < 1.5. Thus, even if having a reduced number of lenses, the wide lens can be produced easily and has reduced distortion. |
