| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact, high variable-power zoom lens which satisfactorily compensates chromatic aberration from a visible region to a near-infrared region, especially, for a monitoring purpose. SOLUTION: The zoom lens includes, in order from an object side: a first group 10 having negative refractive power; a diaphragm St; and a second group 20 having positive refractive power. The power is varied from a wide angle end to a telephoto end by moving the second group 20 to the object side along the optical axis, and the image surface is corrected according as the power is varied by moving the first group 10 along the optical axis. The second group 20 includes, in order from the object side: a 21th lens L21 having at least one aspherical surface, and having positive refractive power; a cemented lens constituted of a 22th lens L22 having positive refractive power and a 23th lens L23 having negative refractive power; a 24th lens L24 having negative refractive power; and a 25th lens L25 having positive refractive power. COPYRIGHT: (C)2008,JPO&INPIT
|
