| 摘要 |
An optical system includes, in order from an object side to an image side, a front unit having a positive refractive power, an aperture diaphragm, and a rear unit. The front unit includes a first lens unit having a positive refractive power. The rear unit includes a second unit adjacent to the aperture diaphragm and configured to move in focusing. The first lens unit includes n (which is an integer of 2 or higher) positive lenses and one or more negative lenses. The materials of at least two positive lenses in the first lens unit satisfy 0.0100<DeltathetagF where DeltathetagF is an abnormal partial dispersion of each material. The material of the one or more positive lenses satisfies 0.0272<DeltathetagF. Additional conditional expressions are satisfied.
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