| 摘要 |
PROBLEM TO BE SOLVED: To provide an imaging lens in which various aberrations are satisfactorily corrected and which has a small F value and a comparatively wide angle of view.SOLUTION: The imaging lens comprises, in order from an object side to an image surface side, an aperture diaphragm ST, a biconvex first lens L1 having refractive power, a meniscus second lens L2 having a concave surface facing the object side in the vicinity of an optical axis and having negative refractive power, a meniscus third lens L3 having a concave surface facing the object side in the vicinity of the optical axis and having positive refractive power, and a fourth lens having a biconcave surface in the vicinity of the optical axis and having negative refractive power. The imaging lens satisfies a conditional expression (1): 0.6<f1/f<0.8 (1), where f1 is the focal length of the first lens and f is the focal length of the entire system of the imaging lens. |
