Verschlusseinrichtung mit automatischer Belichtungszeitsteuerung fuer einaeugige Reflexkamera mit Lichtmessung durch das Objektiv

摘要

A camera shutter timing network includes a photoconductor connected in series with a plurality of diodes, the voltage across the diodes which is a logarithmic function of the photoconductor incident light is amplified by a variable gain amplifier to produce a first voltage. A second diode network combined with variable resistors and an amplifier produces a second voltage which is a logarithmic function of the camera diaphragm opening and film speed rating. A memory capacitor is charged to the difference of the two voltages and a timing capacitor is charged through a diode type logarithmic expansion network at a constant rate dependent on the memory capacitor voltage. An electromagnet energized through a Schmitt type switch releases the shutter to closing upon a predetermined voltage on the timing capacitor. A meter indicates the difference between the first and second voltages and hence the shutter speed.