US4455071A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light measuring instrument for a single lens reflex camera
Assignee: Canon Inc
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Filing: 1982-01-15
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Granted: 1984-06-19
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Expires: 2002-01-15
Abstract
Abstract A light measuring instrument for a single lens reflex camera, whose light measurement distribution can be changed easily, includes two light sensing elements with different light measuring ranges, whereby the desired light measuring distribution can be obtained by changing the outputs of the two light sensing elements.
Inventors
- 👤 Masatake Kato
- 👤 Tokuichi Tsunekawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:34
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/083
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
128 words
A light measuring instrument for a single lens reflex camera, comprising: imaging optics for forming the object image on an image plane; a plurality of light sensing means at least having a first light sensing means for sensing the light from a first part of the object image and a second light sensing means for sensing the light from a second part overlapping and larger than the first part of the object image; a light measuring circuit supplied with outputs of the light sensing means; means for selectively inputting the output from the first and the second light sensing means to the light measuring circuit; and means for changing the ratio of the output of the first light sensing means to that of the second light sensing means.
Claim 2
Dependent Claim
128 words
A light measuring instrument for a single lens reflex camera, comprising: imaging optics for forming the object image on an image plane; a plurality of light sensing means at least having a first light sensing means for sensing the light from a first part of the object image and a second light sensing means for sensing the light from a second part overlapping and larger than the first part of the object image; a light measuring circuit supplied with outputs of the light sensing means; means for selectively inputting the output from the first and the second light sensing means to the light measuring circuit; and means for changing the ratio of the output of the first light sensing means to that of the second light sensing means.
References Cited (Backward Citations)
US4289389A
Cited
US4309090A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-06-19 | 1987-12-19 | 1988-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-06-19 | 1991-12-19 | 1992-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-06-19 | 1995-12-19 | 1996-06-19 | $7700.00 | Window Closed / Lapsed |