| 摘要 |
PROBLEM TO BE SOLVED: To provide an image capturing lens which is compact and has a small F-number, and yet is well corrected for various aberrations and offers a wide view angle.SOLUTION: An image capturing lens comprises, in order from the object side; an aperture stop ST; a biconvex first lens L1 having positive refractive power; a second lens L2 having an object-side surface that is concave near an optical axis and negative refractive power; a meniscus-shaped third lens L3 having a convex surface on the image side and positive refractive power; and a meniscus-shaped bi-aspherical fourth lens L4 having an image-side surface that is concave near the optical axis and negative refractive power. The image capturing lens has an F-number less than 2.4 and satisfies the following conditional expressions: (1) 0.15<f12/f34<0.5, (2) 0.1<|r1/r2|<0.5, (3) 1.0<f1/f3<1.6, where f1 represents a focal length of the first lens, f3 represents a focal length of the third lens, f12 represents a composite focal length of the first and second lenses, f34 represents a composite focal length of the third and fourth lenses, r1 represents a curvature radius of the object-side surface of the first lens, and r2 represents a curvature radius of the image-side surface of the first lens. |
