Photographic camera with through the lens exposure meter

US4180312A · kind A · utility

Assignee

• Ernst Leitz Wetzlar, GmbH · DE

Inventors

• Ewald Schmidt · Ludwigsburg, DE
• Willi Wiessner · Wetzlar, DE

Key dates

• Filing date: Jan 30, 1978
• Grant date: Dec 25, 1979
• Expiry date: Jan 30, 1998

Classification

• Technology area (CPC G): Physics
• CPC primary: G03B7/09972
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

Photographic camera with through the lens exposure metering where the exposure meter is equipped with a silicon- or gallium-arsenide-phosphorus-diode mounted in the space behind the objective and receiving the light. The exposure meter is switchable between integrating and selective metering mode. Two optical systems (12,13) are mounted in front of the light-sensitive diode (10) and are located in the illumination beam being measured. Either of the optical systems is selectively brought into position into the beam in front of the diode (10). One of the systems, namely (13), guides the light from almost the entire object space onto the diode (10). The other system (12) guides only light from a restricted sector of the object space onto the diode (10). By connecting a light intensity attenuator (13a) with the integrating metering system, where the attenuator is moved into the illumination beam being metered together with the integrating system, the attenuator serves to achieve equal illumination intensities on the diode (10) for both the integrated and the selective measurements.