| 摘要 |
PURPOSE: A zoom lens is provided to have a high magnification zoom ratio of more than 2 times, use inexpensive lens materials, and maintain a good aberration performance. CONSTITUTION: The zoom lens system comprises a first lens group(I) having a positive refractive power and a second lens group(II) having a negative refractive power. The distance between the first lens group(I) and the second lens group(II) varies during zooming. The first lens group includes first to fourth lenses(1-4). The first lens(1) has a positive refractive power with a shape of a meniscus lens convex toward an object. The second lens(2) has a negative refractive power with two concave sides. The third lens(3) has a positive refractive power with two convex sides. The fourth lens has a positive refractive power with two convex sides. The second lens group(II) includes a fifth lens(5) having a positive refractive power with a shape of a meniscus lens concave toward an object, a sixth lens(6) having a negative refractive power with a shape of a meniscus lens, and a seventh lens(7) having a negative refractive power.
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