Abstract: A motion picture camera wherein a rotary shutter can be arrested in a first or a second angular position in which its blade respectively overlies and is out of register with the light-admitting aperture. In order to terminate a long exposure which is started with stoppage of the shutter in the second angular position, the user must close an auxiliary switch serving to energize an electromagnet which starts an electric motor for the shutter and simultaneously withdraws a tooth of a pivotable intercepting lever from the path of movement of two projections on the shutter. The first projection approaches and engages the tooth when the shutter is to be arrested in the first position, and the second projection approaches and engages the tooth in the second position of the shutter.