An optical system is provided and includes a fixed assembly, a movable element, a movable assembly, a driving module and a stopping assembly. The fixed assembly defines a main axis. The movable element is movable relative to the fixed assembly and is connected to a first optical element. The movable assembly is connected to the movable element. The driving module is configured to drive the movable assembly so as to drive the movable element to move relative to the fixed assembly. The stopping assembly is configured to limit the range of motion of the movable element.