| 摘要 |
PROBLEM TO BE SOLVED: To provide a system of small-diameter wide-angle zoom lenses of which angle of field at a short focal length end is about 100°or wider and of which zoom ratio is as high as about 2.9 times. SOLUTION: The system of wide-angle zoom lenses are composed of 5 groups of negative, positive, positive, negative, and positive in order from an object. At the time of zooming from a short focal length end to a long focal length end, the first lens group moves toward the image side at first, and then makes a U-turn toward the object side. The interval between the first lens group and the second lens group narrows, the interval between the second lens group and the third lens group narrows, the interval between the third lens group and the fourth lens group widens, and the interval between the fourth lens group and the fifth lens group narrows, so that zooming is implemented, in which case the following formula (1) is met. The formula (1): 0.3<dL<SB>1-2</SB>/dL<SB>2-3</SB><5.0, where dL<SB>1-2</SB>: difference between the interval at the short focal length end and the interval at the long focal point end of the first and second lens groups, and dL<SB>2-3</SB>: difference between the interval at the short focal length end and the interval at the long focal point end of the second and third lens groups. COPYRIGHT: (C)2004,JPO&NCIPI
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