GB1479705A – Photographic cameras
– Google Patents
GB1479705A – Photographic cameras
– Google Patents
Photographic cameras
Info
Publication number
GB1479705A
GB1479705A
GB6445/75A
GB644575A
GB1479705A
GB 1479705 A
GB1479705 A
GB 1479705A
GB 6445/75 A
GB6445/75 A
GB 6445/75A
GB 644575 A
GB644575 A
GB 644575A
GB 1479705 A
GB1479705 A
GB 1479705A
Authority
GB
United Kingdom
Prior art keywords
counter
shutter
generator
pulse
pulses
Prior art date
1974-02-18
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
GB6445/75A
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.)
1974-02-18
Filing date
1975-02-14
Publication date
1977-07-13
1975-02-14
Application filed by Seiko Koki KK
filed
Critical
Seiko Koki KK
1977-07-13
Publication of GB1479705A
publication
Critical
patent/GB1479705A/en
Status
Expired
legal-status
Critical
Current
Links
Espacenet
Global Dossier
Discuss
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
Abstract
1479705 Cameras SEIKO KOKI KK 14 Feb 1975 [18 Feb 1974] 6445/75 Heading G2A A camera has means for generating prior to shutter opening a pulse whose length represents object brightness, a counter for counting standard frequency pulses during the brightness pulse, means for generating a trigger pulse on shutter opening to call out the count to control the shutter opening time and means for terminating the count in the counter ahead of time if the trigger pulse is generated before the brightness pulse ends. Automatic operation. A brightness pulse from a generator 4 opens a NOR gate 5 so that standard pulses from a generator 3 can pass through gate 5 to a counter 7. Pulse counting ceases when the output of generator 4 inverts. This is normally controlled by a switching circuit 4-4 connected to a photo-electric integrating circuit 4-2, 4-3 but in low light conditions if the switching circuit 4-4 has not inverted by the time the shutter opens an input from circuit 18 inverts generator 4. Circuit 18 initiates the generation of subtractive pulses from standard frequency generator 3. When the count in counter 7 reaches zero, a detector 15 closes the shutter. To take account of film speed and diaphragm aperture an appropriate terminal 8-1 to 8-8 is selected to pass the additive pulses from generator 3 to a selected stage of a frequency divider 6 before counter 7 or to pass the pulses direct to a selected stage of counter 7. Manual operation. A terminal 8-1 to 8-8 is selected according to the desired shutter speed. No pulse counting takes place until the shutter opens, whereupon standard pulses from generator 3, pass through all the stages of divider 6 and then to counter 7. Switching elements 16-1 to 16-8 are connected to respective terminals 8-1 to 8-8 and to respective stages of the counter 7. When the counter stage corresponding to the selected element 16-1 to 16-8 is reached, the shutter is closed. An indicator circuit. Fig. 4, (not shown) comprises an array of LEDs (L1 to L5) which, in the automatic mode, indicate shutter speed, over and under-exposure when photography is possible and «overflow» when photography is not possible. The LED’s are extinguished upon shutter release.
GB6445/75A
1974-02-18
1975-02-14
Photographic cameras
Expired
GB1479705A
(en)
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
JP1927174A
JPS576565B2
(en)
1974-02-18
1974-02-18
Publications (1)
Publication Number
Publication Date
GB1479705A
true
GB1479705A
(en)
1977-07-13
Family
ID=11994767
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB6445/75A
Expired
GB1479705A
(en)
1974-02-18
1975-02-14
Photographic cameras
Country Status (5)
Country
Link
US
(1)
US4048642A
(en)
JP
(1)
JPS576565B2
(en)
DE
(1)
DE2504573A1
(en)
FR
(1)
FR2261550B1
(en)
GB
(1)
GB1479705A
(en)
Families Citing this family (2)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
US4306785A
(en)
*
1979-02-01
1981-12-22
Asahi Kogaku Kogyo Kabushiki Kaisha
Camera exposure time control circuit
JPS55155337A
(en)
*
1979-05-23
1980-12-03
Canon Inc
Focus adjuster
Family Cites Families (4)
* Cited by examiner, † Cited by third party
Publication number
Priority date
Publication date
Assignee
Title
DE2006025A1
(en)
*
1970-02-11
1971-08-26
Leitz Ernst Gmbh
Circuit arrangement for viewing knives
JPS4831941A
(en)
*
1971-08-27
1973-04-26
JPS4963430A
(en)
*
1972-10-17
1974-06-19
JPS5640811B2
(en)
*
1972-12-29
1981-09-24
1974
1974-02-18
JP
JP1927174A
patent/JPS576565B2/ja
not_active
Expired
1975
1975-02-04
DE
DE19752504573
patent/DE2504573A1/en
not_active
Withdrawn
1975-02-14
GB
GB6445/75A
patent/GB1479705A/en
not_active
Expired
1975-02-18
US
US05/550,591
patent/US4048642A/en
not_active
Expired – Lifetime
1975-02-18
FR
FR7504974A
patent/FR2261550B1/fr
not_active
Expired
Also Published As
Publication number
Publication date
JPS50115032A
(en)
1975-09-09
JPS576565B2
(en)
1982-02-05
US4048642A
(en)
1977-09-13
DE2504573A1
(en)
1975-08-21
FR2261550A1
(en)
1975-09-12
FR2261550B1
(en)
1978-10-06
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Legal Events
Date
Code
Title
Description
1977-11-23
PS
Patent sealed [section 19, patents act 1949]
1988-10-05
PCNP
Patent ceased through non-payment of renewal fee
