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 three or more lenses, a diaphragm, and a rear unit including a plurality of lenses. The front unit includes a first positive lens closest to an enlargement conjugate position, and a second positive lens. A predetermined condition is satisfied.