| 摘要 |
PROBLEM TO BE SOLVED: To provide an imaging lens suitable for a long focal length lens used in a twin stereoscopic camera. SOLUTION: The imaging lens includes, sequentially from the object side, a first lens L1 having negative refractive power, a second lens L2 having positive refractive power, a diaphragm S, a third lens L3 having negative refractive power, a fourth lens L4 having positive refractive power, and a fifth lens L5 having positive refractive power. The first lens and the second lens are bonded to each other. A focal length f of the whole system, a back focus length BF, a distance OL from the object side surface of the first lens to the image side surface of a lens closest to the image side, a half value H<SB>L1</SB>of an optical effective diameter on the object side of the first lens, a common logarithm log¾fL12¾ of a numerical value representing a composite focal length of the first lens and the second lens fL<SB>12</SB>in mm, satisfy an expression (1): 0.3<(H<SB>L1</SB>/OL)*log¾fL<SB>12</SB>¾<1.0, and an expression (2): 0.7<Bf/f<1.0. COPYRIGHT: (C)2011,JPO&INPIT |
