Patent US4566775A successfully refreshed from Google Patents.
US4566775A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure control apparatus based on a multimetering system
Assignee: Canon Inc
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Filing: 1985-05-21
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Granted: 1986-01-28
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Expires: 2005-05-21
Abstract
Abstract A meter sensitivity pattern control method for cameras in which an output of a first light metering circuit for the brightness of an object of principal photographic interest is compared with outputs of a plurality of second light metering circuits for brightness of different portions of the environment surrounding the object by a corresponding number of comparing circuits. Thereby one second light metering circuit having an output which lies in a predetermined range different from the output of the first light metering circuit and another second light metering circuit having an output which lies outside the predetermined range are selected for their different contributions to an exposure value. The thus-differentially weighed outputs of the second light metering circuits are computed with the output of the first light metering circuit producing light value information.
Inventors
- 👤 Tokuichi Tsunekawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 10:23
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/28; G03B7/08; G03B7/099; G03B7/0993; G03B7/0997; G03B7/09971; G03B7/09976; G03B7/09979
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
205 words
A light metering system for a camera including: (a) first light metering means for measuring the central portion of an object, said means generating an electrical signal corresponding to the brightness of the central portion of the object; (b) a plurality of second light metering means for metering brightness of the surrounding portion of the object, each of said second light metering means generating an electrical signal corresponding to the brightness of the surrounding portion of the object; (c) computing means for computing an output of said first light metering means and outputs of said second light metering means; (d) exposure control means for controlling the amount of exposure in accordance with an output of said computing means; (e) comparison means for comparing the outputs of the first light metering means with those of the second light metering means; and (f) prevention means for preventing the output of each of said second light metering means from being added to said computing means, said prevention means preventing the operation of one or more of said second light metering means whose output is greater than a predetermined difference from the output of the first light metering means on the basis of the signal from the comparison means.
Claim 2
Dependent Claim
205 words
A light metering system for a camera including: (a) first light metering means for measuring the central portion of an object, said means generating an electrical signal corresponding to the brightness of the central portion of the object; (b) a plurality of second light metering means for metering brightness of the surrounding portion of the object, each of said second light metering means generating an electrical signal corresponding to the brightness of the surrounding portion of the object; (c) computing means for computing an output of said first light metering means and outputs of said second light metering means; (d) exposure control means for controlling the amount of exposure in accordance with an output of said computing means; (e) comparison means for comparing the outputs of the first light metering means with those of the second light metering means; and (f) prevention means for preventing the output of each of said second light metering means from being added to said computing means, said prevention means preventing the operation of one or more of said second light metering means whose output is greater than a predetermined difference from the output of the first light metering means on the basis of the signal from the comparison means.
Claim 3
Dependent Claim
195 words
A light metering system for a camera including: (a) first light metering means for measuring the central portion of an object, said means generating an electrical signal corresponding to the brightness of the central portion of the object; (b) a plurality of second light metering means for metering brightness of the surrounding portion of the object, each of said second light metering means generating an electrical signal corresponding to the brightness of the surrounding portion of the object; (c) computing means for computing an output of said first light metering means and outputs of said second light metering means; (d) exposure control means for controlling the amount of exposure in accordance with an output of said computing means; (e) comparison means for comparing the outputs of the first light metering means with those of the second light metering means; and (f) means for reducing the ratio of addition of the output of each of said second light metering means to the computing means, said means reducing the operation of one or more of said second light metering means whose output is greater than a predetermined difference from the output of said first light metering means.
Claim 4
Dependent Claim
195 words
A light metering system for a camera including: (a) first light metering means for measuring the central portion of an object, said means generating an electrical signal corresponding to the brightness of the central portion of the object; (b) a plurality of second light metering means for metering brightness of the surrounding portion of the object, each of said second light metering means generating an electrical signal corresponding to the brightness of the surrounding portion of the object; (c) computing means for computing an output of said first light metering means and outputs of said second light metering means; (d) exposure control means for controlling the amount of exposure in accordance with an output of said computing means; (e) comparison means for comparing the outputs of the first light metering means with those of the second light metering means; and (f) means for reducing the ratio of addition of the output of each of said second light metering means to the computing means, said means reducing the operation of one or more of said second light metering means whose output is greater than a predetermined difference from the output of said first light metering means.
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) | 1989-01-27 | 1989-07-29 | 1990-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-01-27 | 1993-07-29 | 1994-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-01-27 | 1997-07-29 | 1998-01-28 | $7700.00 | Window Closed / Lapsed |