Motion-picture camera programmed for fadeover effects

In a motion-picture camera of the type including a film transport motor, an adjustable diaphragm, and light-sensitive negative-feedback diaphragm control means operative for adjusting the diaphragm setting in dependence upon scene light, including a stepper motor coupled to the diaphragm, and a control circuit operative for operating the stepper motor by generating stepper-motor drive pulses and including components forming a time-constant circuit operative for establishing the repetition frequency of the stepper-motor drive pulses, a novel arrangement for producing fadeover effects, the arrangement comprising, in combination, means for establising m different repetition frequencies for the stepper-motor drive pulses, the first through the mth frequencies being successively higher, including m semiconductor switches each connected to the time-constant circuit for changing the time-constant thereof;

• program-step counting means operative for receiving program-step-change signals and counting in dependence thereon, the program-step counting means being a 1-out-of-n binary counter having n outputs of which successive single ones carry a signal in response to successively received program-step-change signals, the n outputs including first, second and third output groups respectively constituting a fade-out output group, a rewind output group and a fade-in output group, the number of outputs in each group being equal to m;
• means for applying program-step-change signals to the input of the program-step counting means in dependence upon film transport effected by the film transport motor;
• logic circuit means connected to the outputs of the program-step counting means, connected to the negative-feedback diaphragm control means and connected to the film transport motor and operative in dependence upon the count registered on the program-step counting means for effecting a fade-out followed by a limited film rewind followed by a fade-in, by imbalancing the negative-feedback diaphragm control means and controlling the operation of the film transport motor;
• and connecting means connecting respective ones of the first through the mth semiconductor switches to respective ones of the first through the mth outputs of the fade-out output group, and connecting respective ones of the first through the mth semiconductor switches to respective ones of the mth through the first outputs of the fade-in output group, for controlling the conduction of the switches in dependence upon the signals carried on the outputs of the fade-out and fade-in output groups and causing the repetition frequency of the stepper motor drive pulses to increase during the course of a fade-out and decrease during the course of the subsequent fade-in.