The apparatus described serves as an electric drive of a motion picture camera. It permits, in contradistinction to other devices for the same purpose, the independent adjustment of the exposure time and the interval between the exposures. The former can be adjusted between 0.2 and 5 sec., the latter continuously over a range of a factor 5000. Two applications of this apparatus in the field of microcinematography are described, one being the determination of the falling speed of suspended colloid particles in an ultramicroscope, the other being the recording of the growth of etch figures on crystal planes produced by electrolysis.