Patent US4445764A successfully refreshed from Google Patents.
US4445764A
Expired / Lapsed
US
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Light measuring device for a single lens reflex camera
Assignee: Canon Inc
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Filing: 1981-12-01
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Granted: 1984-05-01
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Expires: 2001-12-01
Abstract
Abstract A light measuring device for measuring the light in the field by means of a light sensing means sensing the light reflected of the shutter plane provided in the neighborhood of the image forming plane of the photographing lens or the film plane or both of them. In the optical path of the reflected light a change over means for changing over the light sensitivity distribution of the metering so as to enable the change over of the light.
Inventors
- 👤 Susumu Matsumura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:13
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/099; G03B7/0993; G03B7/0997; G03B7/09979; G03B7/09971; G03B7/09972
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
101 words
A light measuring device for a single lens reflex camera comprising: a photographic lens; a photosensitive means and a shutter plane on the image forming plane of the photographing lens; light sensing means for sensing the light from at least one of the photosensitive means and the shutter plane; a multi-focal lens between the photosensitive means and the light sensing means; said multi-focal lens having a plurality of area zones and having a different focal length for each area zone, and selection means for directing the light from each area zone of the multi-focal lens selectively to the light sensing means.
Claim 2
Dependent Claim
101 words
A light measuring device for a single lens reflex camera comprising: a photographic lens; a photosensitive means and a shutter plane on the image forming plane of the photographing lens; light sensing means for sensing the light from at least one of the photosensitive means and the shutter plane; a multi-focal lens between the photosensitive means and the light sensing means; said multi-focal lens having a plurality of area zones and having a different focal length for each area zone, and selection means for directing the light from each area zone of the multi-focal lens selectively to the light sensing means.
Claim 3
Dependent Claim
24 words
A device according to claim 1, wherein the selection means is a diaphragm means arranged near said multi-focal lens and having an adjustable aperture.
Claim 4
Dependent Claim
261 words
A light measuring device for a single lens reflex camera comprising: a photographic lens defining an image forming plane; image receiving means arranged on the image forming plane of the photographic lens; light sensing means for sensing light from the image forming plane; and filter means including a plurality of filter elements, one of the filter elements being arranged for directing light from a portion of the image to the light sensing means, one of the remaining filter elements directing light from a larger portion of the image to said light sensing means and having a given transmittance distribution or reflective distribution; said filter elements having a prescribed transmission rate or reflection rate; one of the remaining filter elements being arranged for directing light from a larger portion of the image to said light sensing means and having a transmission rate or reflection rate different from that of said one of the filter elements so as to direct a larger amount of light to said light sensing means per unit area of the light incidence on the filter than said one of the filter elements so that when the same photographic object is photometered, the amount of light incident on said light sensing means is not substantially different between said one of the filter elements and said one of the remaining elements; at least either of said one of the filter elements and said one of the remaining filter elements having a number of pinholes for providing said prescribed transmission rate or reflection rate; and means for varying the filter elements.
Claim 5
Dependent Claim
261 words
A light measuring device for a single lens reflex camera comprising: a photographic lens defining an image forming plane; image receiving means arranged on the image forming plane of the photographic lens; light sensing means for sensing light from the image forming plane; and filter means including a plurality of filter elements, one of the filter elements being arranged for directing light from a portion of the image to the light sensing means, one of the remaining filter elements directing light from a larger portion of the image to said light sensing means and having a given transmittance distribution or reflective distribution; said filter elements having a prescribed transmission rate or reflection rate; one of the remaining filter elements being arranged for directing light from a larger portion of the image to said light sensing means and having a transmission rate or reflection rate different from that of said one of the filter elements so as to direct a larger amount of light to said light sensing means per unit area of the light incidence on the filter than said one of the filter elements so that when the same photographic object is photometered, the amount of light incident on said light sensing means is not substantially different between said one of the filter elements and said one of the remaining elements; at least either of said one of the filter elements and said one of the remaining filter elements having a number of pinholes for providing said prescribed transmission rate or reflection rate; and means for varying the filter elements.
Claim 6
Dependent Claim
192 words
A light measuring device for a single lens reflex camera comprising: a photographic lens defining an image forming plane; image receiving means arranged on the image forming plane of the photographic lens; light sensing means for receiving light from the image formed on the image receiving means; filter means between said light sensing means and said image receiving means and including a plurality of filter elements selectively movable into and out of the path between said light sensing means and said image receiving means, one of said filter elements being arranged for directing light from a portion of the image to the light sensing means and another of the filter elements directing light from a larger portion of the image to said light sensing means but having a positionally varying light transmittance distribution so as to vary the weighting of light on said sensing means when the other of the elements is in the path of the light from the image receiving means to the light sensing means; and means for selecting one of the filter elements for placement in the path between said image receiving means and said light sensing means.
Claim 7
Dependent Claim
192 words
A light measuring device for a single lens reflex camera comprising: a photographic lens defining an image forming plane; image receiving means arranged on the image forming plane of the photographic lens; light sensing means for receiving light from the image formed on the image receiving means; filter means between said light sensing means and said image receiving means and including a plurality of filter elements selectively movable into and out of the path between said light sensing means and said image receiving means, one of said filter elements being arranged for directing light from a portion of the image to the light sensing means and another of the filter elements directing light from a larger portion of the image to said light sensing means but having a positionally varying light transmittance distribution so as to vary the weighting of light on said sensing means when the other of the elements is in the path of the light from the image receiving means to the light sensing means; and means for selecting one of the filter elements for placement in the path between said image receiving means and said light sensing means.
References Cited (Backward Citations)
US3205796A
Cited
US3536408A
Cited
US3955208A
Cited
US4142787A
Cited
US4079390A
Cited
US4075640A
Cited
US4040751A
Cited
US4105300A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-05-01 | 1987-10-31 | 1988-05-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-01 | 1991-10-31 | 1992-05-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-01 | 1995-10-31 | 1996-05-01 | $7700.00 | Window Closed / Lapsed |