| 摘要 |
A compact zoom lens system with a high zooming ratio comprises, in order from the object side, a first lens group having a positive refracting power, a second lens group having a positive refracting power and a third lens group having a negative refracting power, in which the first lens group, the second lens group and the third lens group are respectively moved on the optical axis toward the object side during the zooming operation taking place from the wide-angle position as the reference point to the telephoto position, and at least one graded refractive index lens of an axial type which has the distribution of its refractive index in the direction of the optical axis is arranged in at least one lens group, so that the zooming ratio exceeds 2, the fluctuation of aberrations during the zooming operation is small and the flatness of the image surface is favorable.
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