| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens that covers an entire scaling range with high variable power ratio and has high optical performance over an entire screen and to obtain optical equipment having the zoom lens. SOLUTION: A first lens group L1 having positive refractive power, a second lens group L2, a third lens group L3 of having positive refractive power, and a fourth lens group L4 having negative refractive power is provided in order from an object side. The interval between the first lens group L1 and the second lens group L2 at a telephoto end is large to a wide-angle end. Variable power is made by moving the lens groups so that the interval between the third and fourth lens groups L3 and L4 becomes small. The third lens group L3 comprises two of negative and positive lenses in order from the object side and meets the condition of 3.8 < ft/fw < 5.5 1.5 < f1/fw < 3.0 0.6 < f3/fw < 0.9 0.4 < l f4/fw l < 0.7 when the focus distance of an entire system at wide-angle and telephoto ends is set to be fw, ft each and that of an ith lens group is set to be fi. COPYRIGHT: (C)2004,JPO
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