| 摘要 |
A zoom lens sequentially includes, along an optical axis from the object (to be imaged) side, a first lens group which has positive refracting power and is always fixed at a position in the optical axis direction in zooming and focusing, a second lens group having negative refracting power, a third lens group having positive refracting power, and a fourth lens group having positive refracting power. Zooming is performed by moving at least the second lens group and fourth lens group. Focusing is performed by moving at least the fourth lens group. The first lens group includes an optical element having an effect of bending the optical path of a light beam and satisfies the following conditional expression: <?in-line-formulae description="In-line Formulae" end="lead"?>2.0<f1/fw<4.5<?in-line-formulae description="In-line Formulae" end="tail"?> where f1 is the focal length of the first lens group and fw is the focal length of the zoom lens at the wide-angle end.
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