JPS57104122A - Exposure control system for camera - Google Patents
Exposure control system for cameraInfo
- Publication number
- JPS57104122A JPS57104122A JP55180233A JP18023380A JPS57104122A JP S57104122 A JPS57104122 A JP S57104122A JP 55180233 A JP55180233 A JP 55180233A JP 18023380 A JP18023380 A JP 18023380A JP S57104122 A JPS57104122 A JP S57104122A
- Authority
- JP
- Japan
- Prior art keywords
- voltage
- measuring light
- circuit
- logarithmic
- counter
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B7/00—Control of exposure by setting shutters, diaphragms or filters, separately or conjointly
- G03B7/08—Control effected solely on the basis of the response, to the intensity of the light received by the camera, of a built-in light-sensitive device
- G03B7/091—Digital circuits
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Automatic Focus Adjustment (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
- Exposure Control For Cameras (AREA)
- Focusing (AREA)
- Indication In Cameras, And Counting Of Exposures (AREA)
Abstract
PURPOSE:To enable to perform exposure control with high precision in a simple constitution by deciding a logarithmic luminance having a good linearity through comparison and addition or the like by sequentially selecting a group of reference a resistance having constant logarithmic difference of resistance value through counter decoder, etc. CONSTITUTION:A voltage of measuring light is generated from the operational amplifier OP1 in a dark signal detecting circuit 21 in correspondence to the output of measuring light produced by a solid-state image pickup element. When this voltage is within the upper and lower limits of a reference voltage, a gate AG3 is controlled by the counter ADC1 in a circuit for integration time control 23, the counter ADC2 in a pulse control circuit 24, etc., and the integration time of the condenser C2 for the voltage of measuring light from the circuit 21 is controlled. The average voltage of measuring light by this integration is compared with the reference voltage owing to resistance R15... having a constant logarithmic difference in the resistance value in a signal conversion circuit for measuring light 25 and selected in sequene by a decoder DEC or the like. Then, the average voltage is subjected to adding process by an operational amplifier OP2 and logarithmic luminance of a good linearity is decided with a high precision in a simple constitution that has no use of a diode for logarithmic compression and no need of temperature correction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55180233A JPS57104122A (en) | 1980-12-19 | 1980-12-19 | Exposure control system for camera |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP55180233A JPS57104122A (en) | 1980-12-19 | 1980-12-19 | Exposure control system for camera |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS57104122A true JPS57104122A (en) | 1982-06-29 |
Family
ID=16079696
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP55180233A Pending JPS57104122A (en) | 1980-12-19 | 1980-12-19 | Exposure control system for camera |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57104122A (en) |
-
1980
- 1980-12-19 JP JP55180233A patent/JPS57104122A/en active Pending
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