| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens system that is extremely thin when stored, has a wide field angle at the wide angle end and a zooming ratio of approximately three times, and to provide an imaging apparatus and a camera. SOLUTION: The zoom lens system includes a first lens group of negative power, a second lens group of positive power, and a third lens group of positive power. The first lens group has a first lens element of negative power which has a concave face on the image side and a second lens element of positive power which has a convex face on the object side. The second lens group comprises a first cemented lens element composed of two lens elements of powers of different signs, and a second cemented lens element composed of two lens elements of powers of different signs. For zooming, the first to third lens groups move along an optical axis. The zoom lens system satisfies the following conditions: 5.0<αi<SB>w</SB><20.0 and (n<SB>11</SB>-1)×(n<SB>12</SB>-1)≥0.84 (wherein 3.2<f<SB>T</SB>/f<SB>w</SB>,ω<SB>w</SB>>35,αi<SB>w</SB>represents an angle at which the principal light ray of the maximum height image at the wide angle end enters the imaging element, n<SB>11</SB>and n<SB>11</SB>each represent the refractive index of the second lens element,ω<SB>w</SB>represents a half field angle at the wide angle end, f<SB>T</SB>represents the focal distance of the entire system at the telephoto end, and f<SB>w</SB>represents the focal distance of the entire system at the wide angle end). The imaging apparatus and camera are also provided. COPYRIGHT: (C)2009,JPO&INPIT
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