In a motion-picure camera, in combination, an adjustable diaphragm;
- light-sensitive negative-feedback diaphragm control means operative for automatically adjusting the diaphragm setting in dependence upon scene light, including an adjusting motor coupled to the diaphragm, a film-transport motor operative for transporting film and means for generating frame pulses indicative of the number of transported frames;
- pulse-generating means operative for generating a pulse train;
- gating means having an input connected to receive pulses from the pulse-generating means and including selecting means for selecting the gating duration of the gating means to provide at the output of the gating means a reference pulse packet consisting of a selected number of pulses;
- first counting means connected to receive the frame pulses and operative for counting in dependence thereon;
- second counting means;
- comparator means connected to the first and second counting means for generating a program-step-change signal when the counts on the first and second counting means are the same;
- program-step counting means having an input connected to the comparator means and operative for counting program steps in dependence upon program-step-change signals furnished by the comparator means;
- means operative for initiating a sequence of program steps, including means for causing the second counting means to register the pulses of the reference pulse packet;
- means operative at the end of each program step in response to a program-step-change signal from said comparator means for resetting the first counting means for performance of another counting cycle for the next program step;
- logic circuit means connected to the program-step counting means, connected to the negative-feedback diaphragm control means and connected to the film-transport motor and operative for implementing fade-out and fade-in operations by altering the balance of the negative-feedback control means and controlling the energization of the film-transport motor in dependence upon the counts registered by the program-step counting means;
- and adjusting-speed control means connected to the second counting means and to the negative-feedback diaphragm control means, operative for causing the extent to which the adjusting motor alters the diaphragm setting during the course of each counting cycle of the first counting means to be constant irrespective of the number of pulses in the reference pulse packet registered by the second counting means, by automatically setting the adjusting speed of the adjusting motor to a value inversely related to the number of pulses in the reference pulse packet.