Abstract: In an optical system having a lens with adjustable focal length, an adjustable aperture plate, and a light-meter device attached to the aperture plate adjustment device, apparatus for connecting the focal-length adjustment device so that the aperture opening is limited by the focal length adjustment device. Additionally, a signalling device emits a signal of the aperture opening defined by the focal-length adjusting device is smaller than the opening if the aperture plate controlled by the light-meter device. In another embodiment an additional variable aperture is located in front of the light-meter device and the adjustment device for this additional aperture is also connected to the focal-length adjustment device.

Abstract: Motion picture camera, with an objective, in the light path of which, two exposure control devices, on the one hand a diaphragm and on the other hand a shutter, are adjustable by means of a common adjustment drive according to a predetermined program for changing of the light quantity which falls on a film per picture. An additional override, adjustment device is provided for at least one of said two exposure control devices for adjustment thereof independent of the predetermined program.