| 摘要 |
A rear focusing type zoom lens system which comprises, as arrayed sequentially when viewed from the object side, a first lens group having a positive refracting power, second and third lens groups having negative refracting powers, respectively, and serving for zooming function when moved along an optical axis, a fourth lens group having a positive refracting power and constantly fixed stationarily, and a fifth lens group having a positive refracting power and serving for image formation function, wherein focusing is performed by moving a single lens element of the fifth lens group along the optical axis. Due to this arrangement, the number of the lens elements required to move for focusing can be reduced while assuring a high variable magnification power and a smaller F-value.
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