Abstract: A flash device having a charging circuit which is arranged to be capable of changing between a flyback-type boosting action and a forward-type boosting action. The flyback-type boosting action is performed in the initial stage of a charging process and, after that, is changed over to the forward-type boosting action. The arrangement permits a charging action to be efficiently carried out.

Abstract: A capacitor charging apparatus includes a DC/DC converter for stepping up the voltage of a battery and charging the capacitor; a detection circuit that determines whether a primary current of the DC/DC converter reaches a predetermined limit current; a control circuit that controls the DC/DC converter according to a detection signal received from the detection circuit; and a battery-information detection circuit that detects battery information of the battery. The control circuit performs a predetermined calculation using the battery information received from the battery-information detection circuit to determine the predetermined limit current and to vary the primary current of the DC/DC converter so as to control the DC/DC converter each time the capacitor is charged by the DC/DC converter.

Abstract: In a flash apparatus, when it is determined that the oscillation of a voltage boosting circuit is stopped before it is controlled so as to stop, it is possible to continuously charge a voltage to a main capacitor by causing the voltage boosting circuit to continue oscillation by providing a control circuit for oscillating the voltage boosting circuit again. Further, the flash apparatus includes a charged current detecting circuit for detecting the current charged in a main capacitor using an auxiliary power source as a power source. The charged current detecting circuit is simply arranged with a passive element for bypassing a part of the current charged in the main capacitor from a loop through the above-mentioned auxiliary power source.

Abstract: A flash device having a charging circuit which is arranged to be capable of changing between a flyback-type boosting action and a forward-type boosting action. The flyback-type boosting action is performed in the initial stage of a charging process and, after that, is changed over to the forward-type boosting action. The arrangement permits a charging action to be efficiently carried out.

Abstract: An electronic apparatus capable of selectively using a plurality of kinds of batteries includes a battery discriminating circuit for making a discrimination of the kind of the battery used, and a current change-over circuit for changing over a supply current of the battery used, in accordance with a result of the discrimination made by the battery discriminating circuit.

Abstract: In a flash device of the kind preventing a main capacitor from being overcharged by inhibiting a charging action on the main capacitor when the voltage of the main capacitor reaches a predetermined first level, detecting the voltage of the main capacitor by a voltage reference diode and allowing light emission when the voltage of the main capacitor reaches a second level which is higher than the first level, an element having a negative temperature characteristic is connected in series to the voltage reference diode. The arrangement ensures an apposite operation of the flash device irrespective of temperature variations.

Abstract: The invention relates to a visual axis detection apparatus and the like which is constituted by light receiving device for receiving image of an observer's eye, read-out device for reading out the photoelectric conversion signals from the light receiving device, information processing device for extracting a plurality of characteristic information on the basis of the signals read out by the read-out device and outputting information regarding the direction of the observer's visual axis and restricting device for giving a restriction to the read-out area of the light receiving device.

Abstract: An electronic flash device includes a first DC--DC converter circuit of separately-excited type, a second DC--DC converter circuit of separately-excited type, a capacitor to be charged by the first DC--DC converter circuit and the second DC--DC converter circuit, and a discharge tube which converts charging energy charged to the capacitor into light energy. The first DC--DC converter circuit includes a first switching element having a first control electrode, and an a first oscillation transformer to which energization is controlled by the first switching element. A first control pulse signal is supplied to the first control electrode. The second DC--DC converter circuit includes a second switching element having a second control electrode, and an a second oscillation transformer to which energization is controlled by the second switching element. A second control pulse signal is supplied to the second control electrode.

Abstract: An optical apparatus with the visual axis detecting function is comprised of an imaging optical system, visual axis detecting means for detecting to which of a plurality of areas in the field of view of the optical system a visual axis is directed, and focusing means responsive to the output of the visual axis detecting means to detect defocus regarding the area to which the visual axis is directed, and adjust the optical system so as to correct the defocus, the focusing means continuously effecting the detection of the defocus and the adjustment of the optical system when the area to which the visual axis is directed after the correction of the defocus is a moving object.

Abstract: This invention relates to a camera havingsight line detection means for detecting the line of sight of an observer,focus detection means having plural focus detection areas and capable of focus detection in each focus detecting area, andselection means for selecting at least one of the plural focus detecting areas, based on the information of the line of sight detected by the sight line detection means, wherein the selection means is adapted to select the focus detecting area based on the result of focus detection by the focus detection means, according to the state of detection of the line of sight by the sight line detection means.

Abstract: Apparatus with focus detection circuitry and sight axis detection circuitry includes multi-point focus state detection circuitry for detecting focus states of an objective lens for a plurality of areas in a field of view. Sight point detection circuitry is provided for detecting a sight point state (e.g., visual axis) of an observer. Control circuitry is provided for executing, in parallel, a detection operation of the multi-point focus state detection circuitry and a detection operation of the sight point detection circuitry.

Abstract: A camera includes a line-of-sight sensing circuit for sensing a position of a photographer's line-of-sight, and a processing circuit for controlling each of (i) the line-of-sight sensing operation and (ii) at least one other photographic processing operation. The processing circuit controls the line-of-sight sensing circuit to sense the photographer's line-of-sight in parallel with the at least one other photographic processing operation.

Abstract: A focus detection apparatus includes an optical system for forming first and second optical distributions associated with object images whose relative positional relationship is changed in accordance with an imaging state of an imaging optical system subjected to focus detection, a photoelectric conversion element, having a plurality of picture elements, for outputting first and second signals respectively corresponding to the first and second optical distributions, and a calculating unit for performing filter processing of the first and second signals, sequentially displacing the first and second signals relative to each other on the calculation basis, calculating an evaluation amount representing a coincidence between the first and second signals at the relatively displaced positions, obtaining positional deviations between the first and second object images on the basis of a change in evaluation amount, and detecting the imaging state of the imaging optical system on the basis of the deviations.

Abstract: A camera having a camera-shake detecting device is arranged to make a display indicating that a shake of the camera is undetectable only in cases where the camera shake is consecutively found to be undetectable for a given number of times while a camera-shake detecting action is repeatedly performed. This arrangement effectively prevents the display from being flickered by alternate displays of an undetectable state and a detectable state if the undetectable state is displayed every time the undetectable state of camera shake takes place.

Abstract: A camera with focus detecting and hand trembling detecting apparatus includes a focus detecting device for automatic focusing and a hand trembling detection circuit for detecting the hand trembling state of the camera. At the hand trembling detection by the hand trembling detection circuit, the automatic focusing is automatically switched from the servo mode to the one-shot mode, thus enabling exact hand trembling detection.

Abstract: An optical system driving device for a camera includes a displacement mechanism for actuating a photo-taking optical system by displacement; a driving mechanism arranged to alternately take first and second states, to shift the displacement mechanism to a first given degree in a given direction when the first state changes to the second state and to shift the displacement mechanism to a second given degree which is less than the first given degree when the second state a changes to the first state; first stopping mechanism for stopping the driving means in the first state; a second stopping mechanism for stopping the driving means in the second state and photographing means for performing photography under a condition that the driving means is stopped by the first and second stopping means.

Abstract: Disclosed is a focus adjustment information forming device of the kind arranged to measure distances at a plurality of distance measuring areas on a picture plane specified by optical means which has its focal point being adjusted and to form information on adjustment of the focal point, the plurality of distance measuring areas including a center distance area located approximately in the center of the picture plane.

Abstract: A camera of the kind operating under the control of a computer is arranged to shift an operating state of the computer from a normal mode to a hold mode for saving electric energy by detecting a drop in the voltage level of power supply during a load driving process or when an operation member is operated; and to prevent a faulty operation by varying, according to the kind of a load to be driven, a voltage-level-drop detecting level which is set for shifting the computer to the hold mode.

Abstract: The present invention provides a photographic lighting apparatus for illuminating a photographic object in taking the object with a camera such as a television camera or an 8 mm movie camera. The photographic lighting apparatus is capable of illuminating the object practically at a fixed intensity of illumination regardless of the variation of the distance between the object and the lamp thereof by reducing the brightness of the lamp when the object is located near to the lamp and increasing the same when the object is located remotely. The brightness of the lamp is regulated by controlling the conduction angle of a thyristor connected to the lamp according to the output signal of a photometric circuit which measures the intensity of illumination of the object.

Abstract: Disclosed is a focus adjustment information forming device of the kind arranged to measure distances at a plurality of distance measuring areas on a picture plane specified by optical means which has its focal point being adjusted and to form information on adjustment of the focal point, the plurality of distance measuring areas including a center distance area located approximately in the center of the picture plane.