| 摘要 |
A zoom lens includes, in order from an object side, a positive first lens unit which does not move for zooming, a negative second lens unit which moves in an optical axis direction for zooming, a negative third lens unit which moves in the optical axis direction for zooming so as to correct image plane variation due to zooming, and a positive fourth lens unit which does not move for zooming. The fourth lens unit includes, in an order from the object side, a positive first sub lens unit and a positive second sub lens unit, which are separated by a largest air interval in the fourth lens unit. Abbe constants, partial dispersion ratios, and coefficients of the refractive index variation due to the temperature variation are appropriately set for lens materials forming the third lens unit, the first sub lens unit, and the second sub lens unit.
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