| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a zoom lens system, an imaging device and a camera individually having a wide angle of view at a wide angle end and high optical performance in spite of small sizes thereof. <P>SOLUTION: A zoom lens system comprises: a first lens group having negative power; a second lens group having positive power; and a third lens group having the positive power. The zoom lens system individually moves the first lens group, the second lens group and the third lens group along an optical axis in zooming so as to perform variable power. Individual lens groups have one or more lens elements satisfying the following conditional expressions: nd≤1.67, vd<59 and 0.000<PgF+0.002×vd-0.664, where nd represents a refractive index of the lens element with respect to a d line, vd represents the Abbe number with respect to the d line and PgF represents a partial dispersion ratio with respect to a g line and an F line, respectively. The zoom lens system, an imaging device and a camera satisfy the following conditional expressions: 0.31<Ir/√(¾f<SB POS="POST">G1</SB>×f<SB POS="POST">G2</SB>¾) and Ir=f<SB POS="POST">T</SB>×tan(ω<SB POS="POST">T</SB>), where f<SB POS="POST">T</SB>represents a focal distance of an entire system at a telephoto end, ω<SB POS="POST">T</SB>represents a half value of a maximum angle of view, f<SB POS="POST">G1</SB>represents a focal distance of the first lens group and f<SB POS="POST">G2</SB>represents a focal distance of the second lens group, respectively. <P>COPYRIGHT: (C)2012,JPO&INPIT |
