Title: Metering device for cameras

Abstract: In a metering device for cameras comprising an operational amplifier, a photodiode connected between the positive and the negative input terminal of the operational amplifier, and a logarithmic conversion diode connected between the negative input terminal and the output terminal of the operational amplifier, the electric charge stored in the capacity present in the photodiode due to noise may be discharged to a capacitor which is adapted to reduce its potential in synchronism with the output potential drop of the operational amplifier.

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Inventors: Watanabe, Sakuji (Yono, JA)

Application Number: 681506
Filing Date: 1976-04-29
Publication_date: 1977-08-30
Assignee: Nippon Kogaku K.K. (Tokyo, JA)
Primary Class(es): 356/223 250/205, 250/214L, 250/214P, 356/226, 396/228
Other Classes:
US Patent Ref:

3704950	Dec, 1972	Rosencrantz	356/223.
3781119	Dec, 1973	Mori	356/223.
3859519	Jan, 1975	Weischedel	250/214.
3928860	Dec, 1975	Numata et al.	354/60.
3977011	Aug, 1976	Matsuda	356/223.

Other Refs:
Primary Examiner: Corbin, John K.
Assistant Examiner: Levy, Stewart
Attorney: Fitzpatrick, Cella, Harper & Scinto