A device for setting an optical transmission comprises a first side, a second side and an optical component between the first and second sides. The optical component comprises a first optical element and an adjustment mechanism for moving at least the first optical element. The adjustment mechanism is designed to modify the transmission of the optical component by moving at least the first optical element between the first and second sides such that a light intensity on the second side can be set by the movement of the at least first optical element. The adjustment mechanism is designed to move at least the first optical element such that the optical transmission can be adapted with a switching time of less than 1 s, such as less than 1 ms, for example less than 1 s. A system comprises such a device and light source that emits light in a beam path.