US4417794A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic diaphragm control camera
Assignee: Minolta Co Ltd
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Filing: 1982-07-07
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Granted: 1983-11-29
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Expires: 2002-07-07
Abstract
Abstract An automatic diaphragm control camera of the T. T. L light measurement type sets a diaphragm to a fully opened aperture in the case of daylight photographing with a low brightness condition by generating a diaphragm stopping-down prevention signal which serves to deactivate an electromagnetic diaphragm stopping-down release device. Upon receipt of a flash readiness signal from an electronic flash device, however, the camera, in preference to the generation of the diaphragm stopping-down prevention signal, activates the electromagnetic diaphragm stopping-down release device in response to a camera release operation.
Inventors
- 👤 Masaaki Nakai
- 👤 Masayoshi Sahara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 00:22
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/085; G03B7/16
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
166 words
A camera for use with a flash device capable of generating a flash readiness signal, comprising: an objective; a diaphragm normally retained in a fully opened aperture position; discrimination means including means for measuring light through said objective and diaphragm aperture and determining whether said diaphragm is to be set to the fully opened aperture position, based on the light measured through said objective and said diaphragm, a set film sensitivity and a set shutter speed, and generating a diaphragm stopping-down prevention signal when it is determined that said diaphragm is to be set to the fully opened aperture position; diaphragm stopping-down release means for allowing stopping-down of said diaphragm in response to a camera release operation; first diaphragm release control means for deactivating said diaphragm stopping-down release means in response to said diaphragm stopping-down prevention signal from said discrimination means; and second diaphragm release control means for overriding said first diaphragm release control means in response to said flash readiness signal from said flash device.
Claim 2
Dependent Claim
166 words
A camera for use with a flash device capable of generating a flash readiness signal, comprising: an objective; a diaphragm normally retained in a fully opened aperture position; discrimination means including means for measuring light through said objective and diaphragm aperture and determining whether said diaphragm is to be set to the fully opened aperture position, based on the light measured through said objective and said diaphragm, a set film sensitivity and a set shutter speed, and generating a diaphragm stopping-down prevention signal when it is determined that said diaphragm is to be set to the fully opened aperture position; diaphragm stopping-down release means for allowing stopping-down of said diaphragm in response to a camera release operation; first diaphragm release control means for deactivating said diaphragm stopping-down release means in response to said diaphragm stopping-down prevention signal from said discrimination means; and second diaphragm release control means for overriding said first diaphragm release control means in response to said flash readiness signal from said flash device.
Claim 3
Dependent Claim
86 words
A camera as defined in claim 1, further comprising: a shutter; first shutter control means for controlling closing of said shutter in dependence upon the intensity of light measured through said objective and said diaphragm and the set film sensitivity; and second shutter control means for controlling closing of said shutter in response to disappearance of said flash readiness signal due to flashing of said flash device such that said shutter is controlled at a shutter speed completely synchronous with the flashing of said flash device.
Claim 4
Dependent Claim
37 words
A camera as defined in claim 2, wherein said second shutter control means includes a circuit for overriding said first shutter control means in response to said flash readiness signal due to flashing of said flash device.
Claim 5
Dependent Claim
27 words
A camera as defined in claim 1, further comprising flash readiness indication means for indicating the presence of said flash readiness signal from said electronic flash device.
Claim 6
Dependent Claim
18 words
A camera as defined in claim 4, wherein said flash readiness indication means includes a light emitting element.
Claim 7
Dependent Claim
35 words
A camera as defined in claim 1, wherein said flash device is an electronic flash device which generates said flash readiness signal upon reaching a condition ready for flashing with sufficient amount of light emission.
Claim 8
Dependent Claim
137 words
A camera as defined in claim 1, wherein said light measuring means further includes a light measuring circuit having a light receiving element disposed to measure the intensity of the scene light having passed through said objective and said diaphragm and said discriminating means further includes means for calculating a proper shutter speed from the light measurement by said light receiving element and information of the set film sensitivity to generate a proper shutter speed signal; set shutter speed signal generating means for generating a manually set shutter speed signal; and a comparator for comparing said proper shutter speed signal with said set shutter speed signal to generate said diaphragm stopping-down prevention signal when the former signal represents a given relationship with respect to the latter signal with said diaphragm retained in the fully opened aperture position.
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) | 1986-11-28 | 1987-05-30 | 1987-11-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-11-28 | 1991-05-30 | 1991-11-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-11-28 | 1995-05-30 | 1995-11-29 | $7700.00 | Window Closed / Lapsed |