Abstract: The present invention relates to an electronic flash device which, even if the charged voltage of a main capacitor is low, can securely effect a trigger operation by making a trigger voltage higher than the charged voltage of the main capacitor.

Abstract: In a flash photographing system having a light receiving circuit arranged to receive a reflected light from an object caused by a light flux emitted from a flash tube and controlling the amount of flash light emission according to the amount of light thus received, the output of the light receiving circuit is inputted to an analog-to-digital conversion circuit to be converted into digital values at intervals of a predetermined period, and an adding process on the digital values is performed to detect the amount of received light, so that the amount of flash light emission is controlled.

Abstract: There is provided a flash device to which a construction for starting a flash emission without depending on the turning-on of an X-sync contact is added without increasing the number of interfaces between a camera body and the flash device. In the flash device, a change of a clock signal inputted next to emission mode data communicated to the flash device through a serial communication line between the camera body and the flash device is detected and recognized as a flash emission start signal, so that flash emission start control is performed without depending on the turning-on of the X-sync contact and without setting a special interface.

Abstract: A drive frequency control system is used for a vibration driven motor including a vibrating member which generates a vibration therein upon application of a frequency signal to an electro-mechanical energy conversion element therein, and which uses the vibration as a driving force. The system includes a power supply circuit for supplying an electric power to the vibration driven motor, and a detection circuit for detecting a power supply voltage level of the electric power supplied by the power supply circuit, the detection circuit determining whether the power supply voltage level is less than a predetermined voltage level. A control circuit performs frequency control of the frequency signal of the basis of the determination of the detection circuit.

Abstract: A frequency signal control circuit for a vibration type motor apparatus, which uses as a driving force a vibration generated by application of a frequency signal to an electro-mechanical energy conversion element thereof, inhibits a shift operation of the frequency signal to a lower frequency when a detector detects that a voltage level of a power supply is less than or equal to a predetermined first level, and shifts the frequency to a higher frequency when the detector detects that the voltage level is less than or equal to a second level, the second level being lower than the first level.

Abstract: The present invention relates to an apparatus for sequentially controlling a plurality of vibration driven motors by a microcomputer. The present invention provides a control apparatus for constantly monitoring a vibration state of each motor, and when a motor is close to a resonance state, preferentially controlling the motor in a state near resonance by interrupt processing even if the computer is currently controlling another motor.

Abstract: In an information processing device which obtains, by computation, an address corresponding to input information obtained from an input device and reads out data from the computed address, instead of performing an address computing operation every time a data reading action is required, data is directly read out by using a previously computed address in cases where the input information obtained at the time of a current data reading action is judged to be unchanged from input information obtained at the time of a preceding data reading action. The address computing operation is required only when the input information currently obtained differs from input information previously obtained at the time of the preceding data reading action.

Abstract: An optical instrument system has an optical instrument body and an optical accessory instrument. The optical instrument body is capable of accommodating an electric power source and includes a supply circuit for supplying an electric power from the electric power source and a body side circuit for performing digital information communication.