| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens advantageous for satisfying both of the thinning of a lens system when being collapsed and housed and the securement of an f-number showing a bright condition. SOLUTION: When varying power from a wide angle end to a telephoto end, space between first and second lens groups G1 and G2 is narrowed and space between the second and the third lens groups G2 and G3 is widened. The first lens group G1 comprises one single lens, which is a biconcave negative lens, or two lenses, that is, a biconcave negative lens and a positive lens, and the second lens group comprises two positive lenses and one negative lens. At least either of the two positive lenses of the second lens group has an aspherical lens surface. The zoom lens satisfies a conditional expression (1): 16<C<SB>jw</SB>/h<SB>1w</SB><23 (provided that h<SB>1w</SB>means the height of an axial marginal light beam on the incident surface of the first lens group at the wide angle end in the longest distance focused state, and C<SB>jw</SB>means length on an optical axis to an image surface from the incident surface of the first lens group at the wide angle end in the longest distance focused state). COPYRIGHT: (C)2008,JPO&INPIT
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