US4285585A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure control compensating means for close-up photography
Assignee: Fujinon Corp
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Filing: 1979-05-03
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Granted: 1981-08-25
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Expires: 1999-05-03
Abstract
Abstract In an automatic exposure control camera in which exposure is controlled based on an output of an arithmetic unit, the F-value information of the taking lens of the camera in the arithmetic unit is compensated by use of a distance information from a distance detector, and the exposure is controlled based on the compensated F-value, whereby the exposure is compensated in close-up photography.
Inventors
- 👤 Saburo Numata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:29
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/16
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
117 words
In a camera, exposure control apparatus including means for automatically compensating exposure control for close-up photography in accordance with the formula ##EQU2## where FD=effective F-value F=a preselected F-value l=the actual distance from the camera lens to an object to be photographed f=the actual focal length of the lens, and wherein the value of l/(l-f) is always greater than 1, said means comprising: (a) an arithmetic unit; (b) an F-value input means connected to said arithmetic unit; (c) distance information input means connected to said arithmetic unit; (d) a focal length information input means connected to said arithmetic unit; (e) said arithmetic unit providing an effective F-value exposure control output according to said formula based on said inputs.
Claim 2
Dependent Claim
117 words
In a camera, exposure control apparatus including means for automatically compensating exposure control for close-up photography in accordance with the formula ##EQU2## where FD=effective F-value F=a preselected F-value l=the actual distance from the camera lens to an object to be photographed f=the actual focal length of the lens, and wherein the value of l/(l-f) is always greater than 1, said means comprising: (a) an arithmetic unit; (b) an F-value input means connected to said arithmetic unit; (c) distance information input means connected to said arithmetic unit; (d) a focal length information input means connected to said arithmetic unit; (e) said arithmetic unit providing an effective F-value exposure control output according to said formula based on said inputs.
Claim 3
Dependent Claim
17 words
The apparatus of claim 1 wherein said focal length information input means is a focal length--voltage converter.
Claim 4
Dependent Claim
14 words
The apparatus of claim 2 wherein said focal length--voltage converter is a fixed resister.
Claim 5
Dependent Claim
21 words
The apparatus of claim 1 further comprising an exposure control circuit for providing shutter speed information according to the effective F-value.
Claim 6
Dependent Claim
23 words
The apparatus of claim 1 further comprising means for controlling the flashing time of an electronic flash lamp according to the effective F-value.
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) | 1984-08-24 | 1985-02-23 | 1985-08-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-24 | 1989-02-23 | 1989-08-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-24 | 1993-02-23 | 1993-08-25 | $7700.00 | Window Closed / Lapsed |