| 摘要 |
PURPOSE: A compact zoom lens is provided to have a compact size, high performance, and a high zoom lens ratio of at least 2 times, thereby providing arrangement which substantially obviates one or more of the limitations and disadvantages of prior art arrangements. CONSTITUTION: The zoom lens includes two lens groups(I,II). The first lens group(I) has an overall positive refractive power, and includes four lens units(1-4). The first lens unit(1) is a meniscus lens that is convex toward an object, and which has a positive refractive power. The second lens unit(2) is a biconcave lens having a negative refractive power. The third lens unit(3) is a biconvex lens having a positive refractive power, and is fixed to the second lens unit. The fourth lens unit(4) is a biconvex lens having a positive refractive power. The second lens group(II) has an overall negative refractive power, and includes three lens units(5-7). The fifth lens unit(5) which is a meniscus lens, is convex toward the object, and has a positive refractive power. The sixth lens unit(6) is a concave lens having a negative refractive power. The seventh lens unit(7) has a negative refractive power. The magnification of the system can be changed by varying a distance between the first lens group and the second lens group, wherein the following conditions are satisfied:.
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