| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a zoom lens starting from a negative lens group, which yields an advantage in ensuring a field angle at a wide-angle end and reducing the size of the zoom lens, and also an advantage in ensuring a variable power ratio and brightness. Ž<P>SOLUTION: The zoom lens includes, in order from an object side, a first lens group of negative refractive power, a second lens group of positive refractive power, a third lens group of positive refractive power, and a fourth lens group of negative refractive power. When the zoom lens zooms from a wide-angle end to a tele-photo end, the second lens group moves so that the spacing between the first and second lens groups decreases and the spacings between the lens groups changes. The first lens group includes, in order from the object side, one negative lens component at least one face of which is aspherical, and one positive lens component. The fourth lens group includes one negative lens component the object side face which is concave, and satisfies a following conditional expression (1):-4<(R<SB>4a</SB>+R<SB>4b</SB>)/(R<SB>4a</SB>-R<SB>4b</SB>)<-0.5. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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