GB1409479A - Photographic cameras - Google Patents

Photographic cameras

Info

Publication number
GB1409479A
GB1409479A GB3688673A GB3688673A GB1409479A GB 1409479 A GB1409479 A GB 1409479A GB 3688673 A GB3688673 A GB 3688673A GB 3688673 A GB3688673 A GB 3688673A GB 1409479 A GB1409479 A GB 1409479A
Authority
GB
United Kingdom
Prior art keywords
shutter
frequency
duration
exposure time
pulses
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.)
Expired
Application number
GB3688673A
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.)
Seiko Koki KK
Original Assignee
Seiko Koki KK
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 Seiko Koki KK filed Critical Seiko Koki KK
Priority to GB3688673A priority Critical patent/GB1409479A/en
Publication of GB1409479A publication Critical patent/GB1409479A/en
Expired 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
    • G03B7/00—Control of exposure by setting shutters, diaphragms or filters, separately or conjointly
    • G03B7/08—Control effected solely on the basis of the response, to the intensity of the light received by the camera, of a built-in light-sensitive device
    • G03B7/091—Digital circuits
    • G03B7/093—Digital circuits for control of exposure time

Landscapes

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

Abstract

1409479 Shutter control circuits SEIKO KOKI KK 3 Aug 1973 36886/73 Heading G2A Before the shutter opens, a unit 1 measures subject brightness, determines the correct exposure time T therefrom, and produces a gating pulse of duration T/K (K being a constant) which is fed to an AND gate 3 whereby pulses of frequency f from a generator 2 are counted and memorized by a circuit 4 for the duration of the gating pulse; and on shutter opening a frequency divider 5 feeds pulses of frequency f/K to a second counting circuit 6 and a detector 7 closes the shutter when the two counts are equal. In SLR cameras K in such that T max/K is less than the time between pressing the shutter release and the hinging up of the mirror. In Fig. 2 (not shown) a single reversible counter (9) is used, and an exposure time indicator (11) is included. Reference has been directed by the Comptroller to Specification 1340930.
GB3688673A 1973-08-03 1973-08-03 Photographic cameras Expired GB1409479A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB3688673A GB1409479A (en) 1973-08-03 1973-08-03 Photographic cameras

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3688673A GB1409479A (en) 1973-08-03 1973-08-03 Photographic cameras

Publications (1)

Publication Number Publication Date
GB1409479A true GB1409479A (en) 1975-10-08

Family

ID=10391978

Family Applications (1)

Application Number Title Priority Date Filing Date
GB3688673A Expired GB1409479A (en) 1973-08-03 1973-08-03 Photographic cameras

Country Status (1)

Country Link
GB (1) GB1409479A (en)

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Legal Events

Date Code Title Description
PS Patent sealed
PCNP Patent ceased through non-payment of renewal fee