OPTICAL SYSTEM, IMAGE PICKUP APPARATUS, IN-VEHICLE SYSTEM, AND MOVING APPARATUS

An optical system includes, in order from an enlargement conjugate side to a reduction conjugate side, a front unit including a plurality of lenses, an aperture stop, and a rear unit including a plurality of lenses. A projection characteristic of the optical system representing a relationship between a half angle of view and an image height on an image plane satisfies a predetermined condition.