| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the entire optical length and a front ball diameter by properly correcting a spherical aberration, a field curvature, and a distortion aberration in a zoom area. <P>SOLUTION: A zoom lens comprises, in order from an object side, a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power. When varying the power from a wide-angle end to a telephoto end, each group is moved so as to increase the interval between the first lens group and the second lens group and decrease the interval between the second lens group and the third lens group. The first lens group comprises, in order from the object side, a negative lens having a meniscus shape and a positive lens whose both surfaces are convex. The second lens group comprises, in order from the object side, a negative lens, a negative lens whose both surfaces are concave and a positive lens. The third lens group comprises, in order from the object side, a positive lens, a negative lens, and a positive lens. The fourth lens group comprises a positive lens. <P>COPYRIGHT: (C)2013,JPO&INPIT |
