| 摘要 |
PROBLEM TO BE SOLVED: To make a video camera and a digital camera drastically thinner by using a zooming system which has a smaller number of lens pieces, can be easily made smaller and simpler and has high image formation performance. SOLUTION: A zoom lens consists of a negative first group G1, an aperture diaphragm S, a positive second group G2, and a positive third group G3. In performing power variation from a wide angle end to a telephoto end, the second group G2 is moved only to an object side, and the third group G3 is moved while changing its interval with the second group G2. The second group G2 consists of a positive lens, a negative lens, a positive lens and a negative lens. At least either a positive lens or a negative lens of an image side in the second group G2 has an aspheric surface, and satisfies a condition (1) concerning the ratio of a radius of curvature on the optical axis of the surface of the object side of the positive lens of the object side of the second group G2 to that of the surface of an image side of the negative lens of the object side.
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