摘要:
A camera powered by a battery has a first memory area for storing first data used in operating the camera and for retaining the first data irrespective of a power source interruption in the camera, and a second memory area powered by the battery for storing second data which is dependent upon the first data. A power interruption in the camera, such as occurs when the battery is exhausted or replaced, is detected by comparing the first data stored in the first memory area with the second data stored in the second memory area. After detection of a power interruption, the camera is initialized and the first data stored in the first memory area is then copied into the second memory area. Since the first memory area and the second memory area are compared each time the camera is activated, the state of the battery can be reliably checked.
摘要:
A range meter for a camera includes a row of light sources for propagating light to a subject from different directions, and a receiver for receiving reflected light. The receiver provides an output corresponding to a spot thereon at which light is received. The light sources are energized selectively, so that the light sources at the end of the row emit less than the light sources at the center of the row.
摘要:
A distance measuring device may be constructed utilizing a reduced number of components by calculating distance on the basis of the duration of an integration. Pulsed light is projected toward an object. A selecting circuit selectively outputs one of a pair of output voltages from two current-voltage converting circuits, each of which is connected to a position sensitive device which is configured to receive light reflected from the object. A variable-gain amplifying circuit is used for amplifying the selected output voltage and for producing an amplified output voltage. The output voltage of the amplifying circuit is integrated by an integrating circuit. Reference voltage generating circuitry generates two reference voltages having different levels and a comparing circuit compares the output voltage of the integrating circuit with one of a pair of reference voltages. Gain selecting circuitry is used for determining the gain of the variable-gain amplifying circuit on the basis of the output result of the comparing circuit. The distance to the object is determined in accordance with the duration of time that integration is performed by the integrating circuit until the integrated output voltage exceeds one of the reference voltages. Thus, distance may be determined in accordance with the magnitude of the integrated output voltage, the number of times integration is performed or the number of light projections performed by the device.
摘要:
A camera system of the type having a lens shutter, a focal-plane shutter, an aperture defined by the lens shutter, and a camera lens, includes a selector circuit which sets an operation mode to either a lens shutter mode in which the lens shutter is operated as a programmed shutter or a focal-plane shutter mode in which the shutter speed is controlled by the focal-plane shutter and the aperture of the camera system is controlled by the lens shutter; a first driving system which controls the lens shutter; a second driving system which controls the time during which the focal-plane shutter is operated; a sequential control circuit which controls the timing of the first and second driving systems; a setting circuit which sets the focal length of the camera lens; an arithmetic circuit which produces an output signal in response to the brightness of the subject, the distance to the subject, the focal length of the lens and the sensitivity of the film; and a switching circuit which switches the operation mode to the focal-plane shutter mode irrespective of the setting of the selector circuit when the exposure value to be controlled exceeds the programmed exposure value of the lens shutter and for switching either the operation mode or the shutter speed in accordance with the set focal length to prevent photographic blurring during camera shake, in response to the output from the arithmetic circuit.