US3886568A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Photographic camera with automatic exposure control means
Assignee: Canon Inc
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Filing: 1973-11-15
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Granted: 1975-05-27
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Expires: 1993-11-15
Abstract
Abstract A camera is operated with manual setting of the aperture for normal photography, while the exposure time is controlled by a photoelectric cell which also controls a meter which indicates the exposure time in the viewfinder. Manipulation of a ring on the lens tube transfers the operation to flash photography. In usual flash photography a variable resistor adjusted by the focussing of the lens determines the position of the meter movement, which both shows the indication of the aperture in the viewfinder and controls the aperture setting. In another kind of flash photography, where an appreciable amount of daylight is to be taken account of, the shutter timing, instead of being fixed as in usual flash photography, is controlled by a light measurement, although the aperture is controlled by the focus distance. The change over from normal to flash causes the scales in the viewfinder to be changed, either mechanically or optically.
Inventors
- 👤 Mutsunobu Yazaki
- 👤 Yukio Mashimo
- 👤 Mutsuhide Matsuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:56
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/16
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
371 words
A photographic camera having automatic exposure control means for controlling exposure during normal photography and flash photography, comprising: first diaphragm means for adjusting the phototaking aperture; photoelectric converter means for metering the brightness of an object to be photographed; second diaphragm means positioned in front of said converter means and mechanically linked to said first diaphragm means to provide an aperture for said converter means proportional to said phototaking aperture; electronic time limit means for effecting a time limiting operation in response to the output of said photoelectric converter means, said time limit means including a time limiting capacitor, a switching circuit changed over by the voltage of said capacitor, and an electromagnetic means for closing a shutter controlled by the output of said switching circuit; distance information means for providing an electronic output corresponding to the object distance; indicator means selectively connected with said photoelectric converter means or the distance information means by a changeover means hereinafter referred to and including an indicating member arranged to be displaced in response to an electric signal; scanning means for scanning said indicating member, said scanning means being associated with said first diaphragm means to adjust the aperture thereof in accordance with the amount of displacement of said indicating member; scale means carrying thereon indices for indicating F-number and shutter time by reference to said indicating member; and change-over means manually operable to provide flash photography and normal photography settings, which is selectively associated directly with the first diaphragm means and thereby with said second diaphragm means only in normal photography to adjust the respective apertures thereof manually to a selected value, whereby said converter means is conditioned to adjust the shutter time in accordance with the selected value of aperture of the first diaphragm means, said change-over means having electrical switching means for connecting said indicating means with said photoelectric converter means only before shutter release to show the shutter time value and disconnecting it therefrom after shutter release in normal photography and for providing connection of said indicating means with said distance information means and disconnecting it substantially from the converter means to provide a proper aperture value in accordance with an object distance through the scanning means in flash photography.
Claim 2
Dependent Claim
371 words
A photographic camera having automatic exposure control means for controlling exposure during normal photography and flash photography, comprising: first diaphragm means for adjusting the phototaking aperture; photoelectric converter means for metering the brightness of an object to be photographed; second diaphragm means positioned in front of said converter means and mechanically linked to said first diaphragm means to provide an aperture for said converter means proportional to said phototaking aperture; electronic time limit means for effecting a time limiting operation in response to the output of said photoelectric converter means, said time limit means including a time limiting capacitor, a switching circuit changed over by the voltage of said capacitor, and an electromagnetic means for closing a shutter controlled by the output of said switching circuit; distance information means for providing an electronic output corresponding to the object distance; indicator means selectively connected with said photoelectric converter means or the distance information means by a changeover means hereinafter referred to and including an indicating member arranged to be displaced in response to an electric signal; scanning means for scanning said indicating member, said scanning means being associated with said first diaphragm means to adjust the aperture thereof in accordance with the amount of displacement of said indicating member; scale means carrying thereon indices for indicating F-number and shutter time by reference to said indicating member; and change-over means manually operable to provide flash photography and normal photography settings, which is selectively associated directly with the first diaphragm means and thereby with said second diaphragm means only in normal photography to adjust the respective apertures thereof manually to a selected value, whereby said converter means is conditioned to adjust the shutter time in accordance with the selected value of aperture of the first diaphragm means, said change-over means having electrical switching means for connecting said indicating means with said photoelectric converter means only before shutter release to show the shutter time value and disconnecting it therefrom after shutter release in normal photography and for providing connection of said indicating means with said distance information means and disconnecting it substantially from the converter means to provide a proper aperture value in accordance with an object distance through the scanning means in flash photography.
Claim 3
Dependent Claim
47 words
A photographic camera according to claim 1, wherein said scale means includes an F-number indicating scale, a shutter time indicating scale, and cover means for selectively shielding said two scales, said cover means being connected to said indicator means to selectively indicate one of said two scales.
Claim 4
Dependent Claim
40 words
A photographic camera according to claim 1, wherein said distance information means includes a variable resistance means variable in response to adjustment of the object distance, said resistance means being electrically connected with said indicator means through said change-over means.
Claim 5
Dependent Claim
79 words
A photographic camera according to claim 3, wherein said scale means includes an F-number indicating scale, a shutter time indicating scale, and cover means for selectively shielding said two scales, said cover means being mechanically connected to said change-over means so as to be selectively movable so that it is moved to a position for shielding said shutter time indicating scale when said electrical switching means of said change-over means has disconnected said indicator means from said converter means.
Claim 6
Dependent Claim
58 words
A photographic camera according to claim 3, wherein said distance information means includes an electrical switch member and said time limit means includes at least one resistor of a predetermined resistance value, said electrical switch member being connected so as To selectively change over said photoelectric converter means and said resistor into connection with said time limiting capacitor.
Claim 7
Dependent Claim
59 words
A photographic camera according to claim 3, wherein said indicator means includes a short-circuiting circuit and said scanning means includes a clamp member for clamping said indicating member of said indicator means, said short-circuiting circuit being provided with switch means adapted to close in response to shutter release, said short-circuiting circuit being short-circuited after said indicating member is clamped.
Claim 8
Dependent Claim
313 words
A photographic camera having automatic exposure control means for controlling exposure during normal photography and flash photography, comprising: photoelectric converter means for metering the brightness of an object to be photographed; electronic time limit means for effecting a time limiting operation in response to the output of said photoelectric converter means, said time limit means including a time limiting capacitor, a switching circuit changed over by the voltage of said capacitor, and an electromagnetic means for closing a shutter controlled by the output of said switching circuit; distance information means for providing an electronic output corresponding to the object distance; indicator means selectively connected with said photoelectric converter means or the distance information means by a change-over means hereinafter referred to and including an indicating member arranged to be displaced in response to an electrical signal from said photoelectric converter means; scanning means for scanning said indicating member, said scanning means being associated with aperture means to adjust the opening thereof in accordance with the amount of displacement of said indicating member; scale means including an F-number indicating scale, a shutter time indicating scale located normal to the F-number indicating scale, a light source for illuminating said F-number scale, and an optical system for optically overlapping said two scales, having a half mirror obliquely set between the F-number indicating scale and the shutter time indicating scale, and change-over means manaully operable to provide flash photography and normal photography settings, which is selectively associated directly with the aperture means only in normal photography to adjust the opening thereof manually to a selected value, said change-over means having electrical switching means for connecting said indicating means with said photoelectric converter means in normal photography, for providing connection of said indicating means with said distance information means in flash photography, and for enabling the operation of said light source of said scale means in flash photography.
Claim 9
Dependent Claim
313 words
A photographic camera having automatic exposure control means for controlling exposure during normal photography and flash photography, comprising: photoelectric converter means for metering the brightness of an object to be photographed; electronic time limit means for effecting a time limiting operation in response to the output of said photoelectric converter means, said time limit means including a time limiting capacitor, a switching circuit changed over by the voltage of said capacitor, and an electromagnetic means for closing a shutter controlled by the output of said switching circuit; distance information means for providing an electronic output corresponding to the object distance; indicator means selectively connected with said photoelectric converter means or the distance information means by a change-over means hereinafter referred to and including an indicating member arranged to be displaced in response to an electrical signal from said photoelectric converter means; scanning means for scanning said indicating member, said scanning means being associated with aperture means to adjust the opening thereof in accordance with the amount of displacement of said indicating member; scale means including an F-number indicating scale, a shutter time indicating scale located normal to the F-number indicating scale, a light source for illuminating said F-number scale, and an optical system for optically overlapping said two scales, having a half mirror obliquely set between the F-number indicating scale and the shutter time indicating scale, and change-over means manaully operable to provide flash photography and normal photography settings, which is selectively associated directly with the aperture means only in normal photography to adjust the opening thereof manually to a selected value, said change-over means having electrical switching means for connecting said indicating means with said photoelectric converter means in normal photography, for providing connection of said indicating means with said distance information means in flash photography, and for enabling the operation of said light source of said scale means in flash photography.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-26 | 1978-11-25 | 1979-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-26 | 1982-11-25 | 1983-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-26 | 1986-11-25 | 1987-05-27 | $7700.00 | Window Closed / Lapsed |