| 摘要 |
PROBLEM TO BE SOLVED: To provide a small imaging lens holding a satisfactory performance up to a periphery, because coma aberrations on the periphery are cut, by providing a diaphragm on the image side surface of the substrate of a cemented type compound lens.SOLUTION: Since a retrofocus type imaging lens has a high aperture efficiency, a lens sufficiently bright up to the periphery is obtained even if an outer circumferential side light ray incident on a first diaphragm SH1 or passing through the SH1 is cut. On the other hand, by disposing a second diaphragm SH2 so as to satisfy conditional expression (1) on the object side or image side surface of the second lens L2, coma aberrations and high order aberrations outside an axis harmful to performance are cut. Accordingly, a subject image, in which aberrations are satisfactorily corrected up to the periphery, is obtained. Thus, by disposing the second diaphragm on the second lens object side or image side surface, coma aberrations and high order aberrations are cut from a less image height, and satisfactory performance is obtained up to the periphery. An expression (1): Ra<H, wherein Ra is a radius of the second diaphragm, and His a distance from the optical axis of the point, at which the outmost light ray of the maximum image height passes through a surface in which the second diaphragm is formed. |
