JPS57109925A - Brightness warning device of camera - Google Patents

Brightness warning device of camera

Info

Publication number
JPS57109925A
JPS57109925A JP55186511A JP18651180A JPS57109925A JP S57109925 A JPS57109925 A JP S57109925A JP 55186511 A JP55186511 A JP 55186511A JP 18651180 A JP18651180 A JP 18651180A JP S57109925 A JPS57109925 A JP S57109925A
Authority
JP
Japan
Prior art keywords
brightness
level
charging
circuit
comparator
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
JP55186511A
Other languages
Japanese (ja)
Inventor
Ryuji Tokuda
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 JP55186511A priority Critical patent/JPS57109925A/en
Priority to US06/333,575 priority patent/US4482238A/en
Priority to DE3150889A priority patent/DE3150889C2/en
Publication of JPS57109925A publication Critical patent/JPS57109925A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B17/00—Details of cameras or camera bodies; Accessories therefor
    • G03B17/18—Signals indicating condition of a camera member or suitability of light

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Exposure Control For Cameras (AREA)
  • Indication In Cameras, And Counting Of Exposures (AREA)

Abstract

PURPOSE:To realize the accurate decision of brightness without using any special temperature compensating circuit, by charging a time constant capacitor and deciding the brightness based on the charging level. CONSTITUTION:When a release button is pushed down to the 1st stroke position, a low or high brightness warning decision mode is carried out by an SW1. Then a function instruction is given to a comparator 14 via a transistors TRs 12 and 15. If the brightness is higher than a prescribed level, the charging quantity of a capacitor increases for a certain period during which a TR10 is off. And the collector potential of a TR5 is reduced less than the reference potential VTK. As a reult, the comparator 14 delivers repetitively H and L level signals to transmit them to a signal processing circuit 17. The circuit 17 decides the output of the comparotor 14 when the signal given from a control circuit 18 changes from L to H level, and latches the L level signal to turn off a display element 20. In such a way, the brightness can be decided with higher accuracy.
JP55186511A 1980-12-27 1980-12-27 Brightness warning device of camera Pending JPS57109925A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
JP55186511A JPS57109925A (en) 1980-12-27 1980-12-27 Brightness warning device of camera
US06/333,575 US4482238A (en) 1980-12-27 1981-12-22 Brightness warning device for camera
DE3150889A DE3150889C2 (en) 1980-12-27 1981-12-22 Warning device for a camera

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP55186511A JPS57109925A (en) 1980-12-27 1980-12-27 Brightness warning device of camera

Publications (1)

Publication Number Publication Date
JPS57109925A true JPS57109925A (en) 1982-07-08

Family

ID=16189777

Family Applications (1)

Application Number Title Priority Date Filing Date
JP55186511A Pending JPS57109925A (en) 1980-12-27 1980-12-27 Brightness warning device of camera

Country Status (1)

Country Link
JP (1) JPS57109925A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57163222A (en) * 1981-04-30 1982-10-07 Copal Co Ltd Trigger circuit of electric shutter circuit for camera
JPS60220324A (en) * 1984-04-17 1985-11-05 Nitto Kogaku Kk Luminance warning device of ae camera

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57163222A (en) * 1981-04-30 1982-10-07 Copal Co Ltd Trigger circuit of electric shutter circuit for camera
JPS60220324A (en) * 1984-04-17 1985-11-05 Nitto Kogaku Kk Luminance warning device of ae camera

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