Abstract: In a finder optic system having the structure in which a tiltable mirror, in its reflecting position, reflects light entering through the camera objective upward onto a focusing screen where an image of the object to be photographed is formed and light from the image is radiated upward through the condenser lens and a pentaprism into an eyepiece, a light meter arrangement in accordance with an embodiment of the invention comprises a single photo-cell and a glass plate provided with an angular surface formed therein for acceptance of the photo-cell.

Abstract: An automatic exposure control apparatus of electric type for a photographic camera having an exposure control parameter setting means cooperative with a geometrical progression scale in isometric graduation is provided with a resistor device. The device includes a variable resistor having a grounded slider associated with the setting means upon movement thereof for providing a resistor value proportional to the amount of movement of the setting means, but to the reciprocal logarithm of the preselected parameter value. In order to minimize the complexity of a computer circuit responsive to the various outputs of the resistor device for performing photographic Appex computation, a bias voltage is applied to each of the variable resistors in a manner to produce a signal in the form of current proportional to the reciprocal of the amount of movement of the setting means.

Abstract: An exposure control system for a camera capable of deriving more reliable and accurate exposure values over an extended range of scene luminance despite variation of the ambient temperature of the system than was previously possible. The exposure control system is characterized by the use of a photovoltaic cell and a logarithmic converter connected thereto in combination with a voltage stabilizer for providing output current signals of which the values are independent of temperature to the automatic camera diaphragm aperture regulating mechanism. The logarithmic converter consists of an operational amplifier with a feedback diode connected between the input and the output of the operational amplifier.

Abstract: A camera having an indication system to determine suitable diaphragm aperture value by measuring the light penetrating through a photographing lens and to indicate the same digitally, wherein when said diaphragm aperture value exceeds the limit value of exposure control of a camera, a warning indication is given by the indication means to indicate the fact that the diaphragm aperture value is outside of control limit, and the number of input/output lead wires to the indication means is reduced. Thus simplifying the set-up.

Abstract: An exposure control apparatus which can set accurate shutter speed constantly irrespective of changes in ambient temperature and which can eliminate not only an error in shutter speed caused by an expansion semiconductor element but also an error in shutter speed caused by the variation in output characteristics due to variation in temperature of a compression circuit.