US 4,392,727 A · Camera exposure control devices with smoothing circuit

Abstract

A controlling device that determines the diaphragm aperture of the camera in accordance with an output of a light measuring circuit, which detects a light from an object to be photographed being illuminated by a light which includes an alternatingly changing component and has its intensity maintained constant in effect for a given time period. The device is equipped with a smoothing circuit for smoothing the ripple component in the photoelectric output. The smoothing circuit is set to have a charge time constant smaller than the discharge time constant and generates an output equivalent to the peak value of the ripple component. The light that illuminates the photographic object can be generated from the electronic flash and the photoelectric detector may be arranged within the body of a camera to receive the light from the photographic object that passes through the diaphragm aperture of the camera.

Claims5

Dependent claims

A camera exposure control circuit, comprising:

a photoelectric circuit including a photoelectric element to receive light from an object to be photographed through the camera diaphragm aperture for generating a voltage output as a function of a brightness of an object to be photographed;
a control circuit for controlling the camera exposure in accordance with said voltage output including a comparison circuit for comparing said voltage output, at the time when the diaphragm aperture is being stopped-down, with a given voltage level, and providing an inverted output when said voltage output attains a specified relationship with said given voltage level, and further including means for stopping the stopping-down operation of the diaphragm in response to said inverted output;
and
a smoothing circuit connected between said photoelectric circuit and said control circuit and having a smaller charging time constant than the discharging time constant thereof.

1 more element

Dependencies are inferred from the claim text.

Camera exposure control devices with smoothing circuit

Life of this patent

Camera exposure control devices with smoothing circuit

Life of this patent

Abstract

Claims5