| 摘要 |
PROBLEM TO BE SOLVED: To obtain a three-group zoom lens for a digital camera or a video camera, where a 1st lens group is constituted of a negative lens and a positive lens, on at least either of which an aspherical surface expressed by an aspherical expression having values in the terms of an odd-numbered order and an even-numbered order is formed, and further satisfies a specified conditional expression, whereby aberration including lateral chromatic aberration in the case of attaining a wide angle is restrained to be small, and further whose entire length at the collapsing time is shortened. SOLUTION: In the zoom lens, respective negative, positive and positive lens groups G<SB>1</SB>, G<SB>2</SB>and G<SB>3</SB>are arranged from an object side, and the lens groups G<SB>1</SB>and G<SB>2</SB>are moved so that space between them may be decreased at the time of varying power to a telephoto side, and the lens group G<SB>3</SB>is moved to the object side at the time of focusing to a short distance side. The lens group G<SB>1</SB>is constituted by arranging the negative lens L<SB>1</SB>and the positive lens L<SB>2</SB>from the object side. It satisfies following expressions. 36.0<θw<41.0 andν<SB>d1</SB>-ν<SB>d2</SB>>20.5: provided thatθw is a half viewing angle at a wide angle end andν<SB>d1</SB>andν<SB>d2</SB>are the Abbe numbers (d-line) of the 1st and the 2nd lenses. COPYRIGHT: (C)2005,JPO&NCIPI
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