JPS5476229A - Photometry circuit - Google Patents

Photometry circuit

Info

Publication number
JPS5476229A
JPS5476229A JP14357177A JP14357177A JPS5476229A JP S5476229 A JPS5476229 A JP S5476229A JP 14357177 A JP14357177 A JP 14357177A JP 14357177 A JP14357177 A JP 14357177A JP S5476229 A JPS5476229 A JP S5476229A
Authority
JP
Japan
Prior art keywords
output
brightness
immediately
becomes
amplifier
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP14357177A
Other languages
Japanese (ja)
Inventor
Tokuichi Tsunekawa
Toshio Sakane
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Canon Inc
Original Assignee
Canon Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Canon Inc filed Critical Canon Inc
Priority to JP14357177A priority Critical patent/JPS5476229A/en
Publication of JPS5476229A publication Critical patent/JPS5476229A/en
Pending legal-status Critical Current

Links

Landscapes

  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)
  • Exposure Control For Cameras (AREA)

Abstract

PURPOSE: To immediately stabilize the output of photometry circuit by providing a switch means which forms a charging path relative to the junction capacity of logarithmic conversion element of the photometry circuit, regulating the charging path based on the value of the photo-electric current, and immediately causing the charged amount to correspond to the brightness of an object to be photographed.
CONSTITUTION: In making electric power switchs SW1, SW2 ON, C1 and C2 are charged to make amplifier A, inoperative, but C1 and C2 immediately discharge due to switch S2 which maintins ON for the predetermined period of time after having been energized so that the amplifier A1 retruns to its operative state. However, C0 is short- circuited at S2, hence the output V0 of the amplifier A1 is lower than the output V1 corresponding to the brightness. After this state, S2 becomes OFF. Meanwhile, the photoelectric current which flows through the ploto-electric conversion element P1 becomes the electric current which corresponds to the brightness of the object L1, and the output of R1 becomes V1. Control circuit CC delivers its output during V0<V1 to make S3 ON. Hence the accumulated electric charge of C0 charged via S3 immediately becomes the charge level corresponding to the brightness, the output V0 of A1 increases to coincides with V1, and the output of photometry circuit is immediately stabilized to the output corresponding to the brightness after having energized thereto.
COPYRIGHT: (C)1979,JPO&Japio
JP14357177A 1977-11-30 1977-11-30 Photometry circuit Pending JPS5476229A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP14357177A JPS5476229A (en) 1977-11-30 1977-11-30 Photometry circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP14357177A JPS5476229A (en) 1977-11-30 1977-11-30 Photometry circuit

Publications (1)

Publication Number Publication Date
JPS5476229A true JPS5476229A (en) 1979-06-18

Family

ID=15341837

Family Applications (1)

Application Number Title Priority Date Filing Date
JP14357177A Pending JPS5476229A (en) 1977-11-30 1977-11-30 Photometry circuit

Country Status (1)

Country Link
JP (1) JPS5476229A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0022524A1 (en) * 1979-07-16 1981-01-21 Miles Laboratories, Inc. Sensor-integrator system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0022524A1 (en) * 1979-07-16 1981-01-21 Miles Laboratories, Inc. Sensor-integrator system

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