GB1527084A - Single lens reflex camera including automatic exposure control apparatus - Google Patents

Single lens reflex camera including automatic exposure control apparatus

Info

Publication number
GB1527084A
GB1527084A GB4426675A GB4426675A GB1527084A GB 1527084 A GB1527084 A GB 1527084A GB 4426675 A GB4426675 A GB 4426675A GB 4426675 A GB4426675 A GB 4426675A GB 1527084 A GB1527084 A GB 1527084A
Authority
GB
United Kingdom
Prior art keywords
shutter
voltage
aperture
exposure control
vra
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
GB4426675A
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.)
Pentax Corp
Original Assignee
Asahi Kogaku Kogyo Co Ltd
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 Asahi Kogaku Kogyo Co Ltd filed Critical Asahi Kogaku Kogyo Co Ltd
Publication of GB1527084A publication Critical patent/GB1527084A/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
    • G03B7/081—Analogue circuits
    • G03B7/085—Analogue circuits for control of aperture
    • 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
    • G03B19/00—Cameras
    • G03B19/02—Still-picture cameras
    • G03B19/12—Reflex cameras with single objective and a movable reflector or a partly-transmitting mirror

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Exposure Control For Cameras (AREA)

Abstract

1527084 SLR camera ASAHI KOGAKU KOGYO KK 28 Oct 1975 [29 Oct 1974] 44266/75 Heading G2A An SLR camera has an exposure control circuit which upon release stores a signal corresponding to subject brightnesss B, and stops down the aperture to a value dependent on the stored brightness signal and on signals representing film speed and shutter time. As shown, a photo-diode PD measures B and is connected to a transistor Q3 which is self biased through a buffer circuit Q1, Q2 so that its collector current equals the photocurrent and its base-emitter voltage V 1 is proportional to the APEX value B v . A resistor VRS is set according to film speed S and diodes D1, D2 provide a voltage V 2 which represents S v and is applied to the emitter of Q3 so that the base voltage V 3 =V 1 + V 2 , i.e. V 3 α B v + S v . Resistors VRT and VRA are set according to shutter time and maximum aperture respectively and a voltage V 6 is produced given by V 6 α T v + A v . V 3 and V 6 are fed to a comparator COM which controls an electromagnet MAG (19) in Fig. 2 (not shown). Upon shutter release a memory switch SWM is opened, the reflex mirror hinges up and a drive lever (11) stops down the aperture and simultaneously alters VRA. When V3 = V 6 i.e. when B v + S v = T v + A v , the comparator COM de-energizes the electromagnet to halt aperture adjustment and the shutter is opened. Figs. 2, 3, 4 and 5 (not shown) show the mechanism for operating the mirror, shutter and diaphragm.
GB4426675A 1974-10-29 1975-10-28 Single lens reflex camera including automatic exposure control apparatus Expired GB1527084A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP12456474A JPS5150730A (en) 1974-10-29 1974-10-29 ICHIGANREFURETSUKUSUKAMERANO JIDOROSHUTSUSEIGYOSOCHI

Publications (1)

Publication Number Publication Date
GB1527084A true GB1527084A (en) 1978-10-04

Family

ID=14888590

Family Applications (1)

Application Number Title Priority Date Filing Date
GB4426675A Expired GB1527084A (en) 1974-10-29 1975-10-28 Single lens reflex camera including automatic exposure control apparatus

Country Status (3)

Country Link
JP (1) JPS5150730A (en)
DE (1) DE2548437A1 (en)
GB (1) GB1527084A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2272304A (en) * 1992-10-21 1994-05-11 Asahi Optical Co Ltd Exposure control apparatus of camera

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5023818A (en) * 1973-07-04 1975-03-14
JPS50158328A (en) * 1974-06-10 1975-12-22

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2272304A (en) * 1992-10-21 1994-05-11 Asahi Optical Co Ltd Exposure control apparatus of camera
US5325147A (en) * 1992-10-21 1994-06-28 Asahi Kogaku Kogyo Kabushiki Kaisha Exposure control apparatus of a camera
GB2272304B (en) * 1992-10-21 1996-09-25 Asahi Optical Co Ltd Exposure control apparatus for a camera

Also Published As

Publication number Publication date
DE2548437A1 (en) 1976-05-13
JPS5150730A (en) 1976-05-04

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Legal Events

Date Code Title Description
PS Patent sealed
746 Register noted 'licences of right' (sect. 46/1977)
PCNP Patent ceased through non-payment of renewal fee