| 摘要 |
A zoom lens system includes, in order from the object side to the image side, four lens units having positive, negative, negative and positive refractive powers. A first lens unit includes, in order from the object side to the image side: a front subunit having a negative refractive power; a middle subunit that has a positive refractive power and moves during focusing; and a rear subunit having a positive refractive power. The zoom lens system further includes a variable apex angle prism disposed on the image side of the front subunit. An average Abbe number of materials of a negative lens element and a positive lens element included in the front subunit is set appropriately so as to suppress occurrence of decentering aberration accompanying a variation of a prism apex angle.
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