| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a zoom lens having a high optical performance in a zoom range of a wide viewing angle. <P>SOLUTION: The zoom lens is composed of: a first lens group having negative refractive power; a second lens group having positive refractive power; a third lens group having negative refractive power; and a fourth lens group having positive refractive power in this order from an object side to an image side and zooms by varying the intervals between respective lens groups. In this case, the first lens group comprises a negative lens and a positive lens with a surface on the object side in a projecting shape in this order from the object side to the image side, and focal distance f1 of the first lens group, focal distance f3 of the third lens group, Abbe number νd1p of the material for the positive lens in the first lens group, focal distance f3i in the air of a single lens which is the "i"th counting from the object side included in the third lens group, and Abbe number νd3i for the material of the "i"th single lens counting from the object side included in the third lens group, sum Σ of the focal distance f3i and the Abbe number νd3i of all single lenses included in the third lens group, are respectively and suitably set. <P>COPYRIGHT: (C)2012,JPO&INPIT |
