CN1144914A - Successive brightness measuring device for camera and measuring method - Google Patents
Successive brightness measuring device for camera and measuring method Download PDFInfo
- Publication number
- CN1144914A CN1144914A CN95107106A CN95107106A CN1144914A CN 1144914 A CN1144914 A CN 1144914A CN 95107106 A CN95107106 A CN 95107106A CN 95107106 A CN95107106 A CN 95107106A CN 1144914 A CN1144914 A CN 1144914A
- Authority
- CN
- China
- Prior art keywords
- brightness
- shutter
- shutter release
- camera
- exposure value
- 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.)
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Classifications
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- 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
- G03B17/00—Details of cameras or camera bodies; Accessories therefor
-
- 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
- G03B7/093—Digital circuits for control of exposure time
Abstract
An exposure value determination system which measures the light reflected off an object whose image is to be recorded when a first step release switch S1 is activated. The image of the object is recorded at a calculated exposure value when a second step release switch S2 is activated. If the time between the activation of the first step release switch and the second step release switch exceeds a predetermined time limit, an exposure value determination circuit measures the light a second time and calculates a new exposure value. If the predetermined time is again exceeded before the second step release switch is activated, the exposure value determination circuit will measure the light again and calculate a new exposure value.
Description
The present invention relates to be used for the Exposure Control Module of imaging.Specifically, the present invention relates to the determining of exposure value of the object that moving or the illumination condition object imaging in changing.
During imaging, exposure value and arrival image forming medium, relevant such as the light quantity of egative film.Brightness measuring circuit is measured light that reflection leaves object to determine exposure value.
In traditional still life photography camera, when the user pushes the shutter button with the picked-up photograph, start first order shutter release, then start second level shutter release.When first order shutter release started, automatic range observation circuit was measured the distance with object, and brightness measuring circuit is measured the ambient brightness around object.The brightness value that microcontroller is measured according to brightness measuring circuit calculates suitable exposure value.When second level shutter release started, the micro-controller instructions shutter was opened and is set a selected iris ring so that egative film is exposed according to exposure value.
Traditional brightness measuring device for camera is only measured once light to each exposure, and shutter speed is determined according to this one-shot measurement.But condition may change during the action of first and second grades of shutter releases.Object may move, and camera may move, or illumination may change.If object moves in the time interval before second level shutter release starts, the user just can not obtain the photograph with correct exposure effect, because exposure value is to move the brightness value that is measured before according to object to determine.
Therefore, with traditional brightness measuring device for camera, because shutter is to move according to the exposure value of measuring in the past that brightness value calculated, and the ambient brightness around measured object may change before second level shutter release starts, the user just can not obtain to have the photograph of correct exposure performance.
The object of the present invention is to provide a kind of problem that can overcome conventional apparatus and shortcoming, be used for the successive brightness measuring device for camera of camera and relevant control method.
Advantage of the present invention and purpose will be partly articulated in the following description, and part will be obvious as seen from instructions, or can be understood by practice of the present invention.Advantage of the present invention and purpose will be achieved and finish by fundamental of specifically noting in the appended claim and combination.
In order to realize said advantage and consistent, as concrete and explanation that summarize, the present invention includes the successive brightness measuring device for camera that a camera is used here with purpose of the present invention.The user starts first and second grade shutter release.When starting first order shutter release, measured around the ambient brightness of object.Then, after first order shutter release starts, in the schedule time when second level shutter release does not start,, the ambient brightness around object is carried out continuous coverage by each predetermined time interval.Then, when second level shutter release starts, calculate exposure value according to the brightness value that measures at last.
A kind of method of measuring the ambient brightness that is used for camera continuously comprises: measure the ambient brightness around object when starting first order shutter release; Determine first order shutter release starting back and whether second level shutter release has crossed a preset time when not starting; According to definite result measure ambient brightness continuously by each predetermined time interval around object; And the brightness value that starting measures before at last according to second level shutter release calculates the exposure value of camera.
Should be understood that the front in a word bright with elaborating of back only be example and explanation, rather than as the restriction of invention required for protection.
Enroll and constitute the accompanying drawing of a present patent application instructions part, one embodiment of the invention are described, and, be used for explaining principle of the present invention with the explanatory note part.In the accompanying drawing:
Fig. 1 is the block scheme that is used for illustrating according to a kind of successive brightness measuring device for camera of the preferred embodiments of the invention;
Fig. 2 is the detailed circuit diagram of expression according to the brightness measuring circuit of the successive brightness measuring device for camera of the preferred embodiments of the present invention;
Fig. 3 is the capacitor charge time curve map of expression according to the brightness measuring circuit in the preferred embodiments of the invention;
Fig. 4 is the flow chart of steps according to the method that is used to measure continuous brightness in the preferred embodiments of the invention;
Fig. 5 is the successive brightness measuring device for camera running sequential chart of expression the preferred embodiments of the invention.
When first order shutter release started, exposure value determined that systematic survey goes out the light that object reflected that will be recorded by its image.When starting, second level shutter release just gets off with the exposure value that calculated image recording with object.If the time between the starting of first order shutter release and second level shutter release has surpassed a certain preset time restriction, then exposure value determines that circuit also calculates the exposure value that makes new advances with regard to photometry for the second time.If surpassed preset time again before the starting of second level shutter release, then exposure value is determined circuit photometry and calculate second new exposure value once more.Therefore,, between the starting of first and second grade shutter release, move, then will use new exposure value to write down its image if be recorded the object of image.And if illumination condition change between first order shutter release starting and the starting of second level shutter release, then exposure value determines that circuit just determines new exposure value according to new illumination condition.
As shown in Figure 1, control by microcontroller 40 according to the successive brightness measuring device for camera of a kind of embodiment of the present invention.Microcontroller 40 and first order shutter release S1, second level shutter release S2, automatic range observation circuit 10, brightness measuring circuit 20, egative film light sensitivity sensor 30, and the termination of switch S 1 and S2 is connected.
Automatically the distance between range observation circuit 10 surveying cameras and the object that will write down.The ambient brightness that brightness measuring circuit 20 is measured around object.Egative film light sensitivity sensor 30 is measured the light sensitivity of egative film.Microcontroller is also being controlled shutter 50, motor gear train 60, and information display 70.Brightness measuring circuit can be got various ways.For example, can adopt the incident-type photometer, maybe can adopt the baffled photometer of measuring such as light-spot type, mean value formula or matrix form.
Fig. 2 represents to can be used for the wiring diagram of the embodiment of a kind of brightness measuring circuit of the present invention.This brightness measuring circuit comprises the light receiving element Cds of a photoresistance type.The resistance value of this light receiving element Cds changes with the light quantity that drops on the light receiving element Cds.Microcontroller sends signal by the joint that indicates OUT to brightness measuring circuit, and by indicating the joint received signal of IN.
Brightness measuring circuit includes comparer IC1 and three bipolar transistor T1, T2 and T3.Each transistor T 1, T2 and T3 have base stage, collector and emitter.Voltage source Vcc and capacitor C 1 are connected in parallel between the emitter of ground voltage and transistor T 1.The collector of transistor T 2 is connected with the base stage of transistor T 1, and the emitter of transistor T 2 is connected to ground voltage.The base stage of transistor T 2 receives input pulse by the OUT joint from microcontroller 40.
The collector of transistor T 1 is connected with resistance R 1, light receiving element Cds, variable resistor VR1 and resistance R 4.Resistance R 1 and R2 form the collector of transistor T 1 and the voltage divider between the ground voltage.The output of voltage divider is connected with the inverting terminal of comparer IC1.Light receiving element Cds and variable resistor VR1 are connected in parallel between the collector and resistance R 3 of transistor T 1.Resistance R 3 makes light receiving element Cds be connected to the noninvert end of comparer IC1, and is connected to ground voltage by capacitor C 2.
The collector of bipolar transistor T3 is connected to the noninvert end of comparer IC1, and the grounded emitter of this transistor T 3.The base stage of transistor T 3 is connected with the base stage of transistor T 1 and the collector of transistor T 2.The output of comparer IC1 connects resistance R 4, and is connected to microcontroller 40 by the IN joint.
Below, with reference to accompanying drawing the operation of camera is according to embodiments of the present invention described.
As shown in Figure 4, apply electric cranking (step 100) during beginning.Microcontroller 40 pairs of all operations circuit, units of variance and internal timers are provided with initial value (step 110) and confirm then whether first order shutter release S1 starts (step 120), when the user presses shutter release with picked-up object photograph, start first order shutter release S1 and make corresponding electric signal input microcontroller 40.
Export the base terminal that puts on transistor T 2 in the brightness measuring circuit 20 by the high level drive signal that microcontroller 40 produces, and transistor T 2 conductings.When transistor T 2 conductings, transistor T 2 collector potentials are with regard to step-down, and make low level signal impose on the base stage of transistor T 1 and T3.Transistor T 1 conducting, and transistor T 3 disconnects.
By the voltage that transistor T 1 is applied, capacitor C 2 is charged according to the resistance value of light receiving element Cds.The resistance value of light receiving element Cds changes with the ambient brightness around object.And the charging rate of capacitor C 2 changes with the resistance value of light receiving element Cds.
When because the charging voltage of capacitor C 2 increases, and the voltage ratio that puts on the noninvert end of comparer IC1 is applied to the voltage of paraphase end of comparer IC1 when high, the output of comparer IC1 becomes high level by low level.This output is sent to microcontroller 40 (step 160) then.
The brightness situation of the object when microcontroller 40 reads on the counting of timer internal and the IN end that definite high level signal is presented on brightness measuring circuit 20.Microcontroller 40 is confirmed: when reading number is that then the brightness of measured object is too high when first predetermined value is following, then the brightness of measured object is low excessively when reading number is higher than second predetermined value.Microcontroller 40 confirms, when counting brightness less than 8 time high and low when counting greater than 80 the time brightness.
Fig. 3 is illustrated in the charging rate of capacitor C 2 under different illumination conditions A, B, the C situation.According to the difference of the ambient brightness that centers on object, the capacitor charging rate changes thereupon, and correspondingly, curve A shows high brightness, and curve C shows low-light level.Curve B shows the brightness that is between A and the C.
If brightness low excessively (step 170), then 70 couples of users of microcontroller 40 activation bit displays give a warning (step 180 is to 190).Microcontroller 40 also transfers to shutter speed minimum or minimum speed.If brightness too high (step 200), then microcontroller 40 makes shutter speed regulate maximum or prestissimo (step 210).
When the counting that measures is between first and second predetermined values, thereby brightness had been when both not too low also not too high, and microcontroller 40 is determined shutter speed (step 220) by driving with measured counting fixed automatic exposure program.
After shutter speed was determined in brightness according to object, microcontroller 40 was by driving automatic range observation circuit 10 with distance between surveying camera and the object.Then, microcontroller 40 is finished automatic distance calculation (step 230 is to step 240) according to measure distance.
Finish after the automatic distance calculation, microcontroller 40 confirms whether second level shutter release S2 move (step 250), and confirm second level shutter release S2 not by the starting time in, whether passed through the schedule time (step 260).If passed through preset time, then microcontroller 40 turns to step 150.In step 150, microcontroller 40 drives brightness measuring circuit 20 to measure brightness.
Therefore, if object changes the position or camera changes the position, then microcontroller 40 calculates a new exposure value.If illumination changes between first and second grades of shutter release startings, also calculate a new exposure value.Microcontroller 40 is according to after second level shutter release S2 carries out continuous coverage with the schedule time to the ambient brightness around object during by starting, and just in time measured brightness value comes the calculation exposure value before second level shutter release S2 starting.
Second level shutter release is by pushing shutter and measuring around the ambient brightness of measured object and started.The ambient brightness that centers on object carries out continuous coverage when being the shutter release unstart of the middle at the fixed time second level, thus, brightness corresponding to the object that took place because of the position or the camera state variation of object before second level shutter release S2 starting changes the photo that can obtain to have proper exposure.
The present invention is illustrated with regard to still life photography camera aspect.But the present invention can be used for other device of measuring the brightness that centers on the object under mobile object or the illumination condition change condition.For example, the present invention can be used in the optical measuring device.And the present invention has the advantage of low cost and high reliability.
Though, only disclose and illustrated a preferred embodiment of the present invention and selectable improved form,, clearly, in appended claim scope, it is possible implementing alternate manner of the present invention and improving.
Claims (10)
1, a kind of successive brightness measuring device for camera that is used for camera comprises:
First and second grades of shutter releases by user's operation;
Be used for the schedule time after said first order shutter release starting, when the shutter release unstart of the said second level, by the mechanism of each predetermined time interval continuous coverage around the ambient brightness of object; And
The brightness value that is used for measuring at last when starting according to said second level shutter release calculates the mechanism of exposure value.
2, according to the described device of claim 1, it is characterized in that, also comprise:
The mechanism that is used for distance between surveying camera and the object;
Be used for the mechanism that sensing is contained in the egative film light sensitivity of camera;
Be used for making the mechanism of the egative film exposure that is contained in camera;
Be used to transmit the mechanism of the egative film of having taken a picture;
When the ambient brightness around object hangs down, be used to warn the low excessively mechanism of amount of brightness of the above-mentioned measurement of user.
3, according to the described device of claim 2, it is characterized in that, said sense mechanism sensing egative film light sensitivity, and said measuring mechanism measuring distance when first order shutter release starts,
And, also comprise when crossing around the ambient brightness of object when low shutter speed be transferred to minimum value, and when the ambient brightness that centers on object is too high, shutter speed is transferred to peaked mechanism,
Wherein, said calculation mechanism according to measure measured brightness value is determined exposure value to the distance of object and when ambient brightness is neither too high when hanging down only, and
Also comprise, when the shutter release of the starting second level, make the mechanism of shutter running so that object is photographed according to determined exposure value.
4, according to the described device of claim 3, it is characterized in that whether too high or too low the said mechanism that is used for measurement environment brightness continuously comprise and be used to measure institute's elapsed time and determine around the ambient brightness of object mechanism according to institute's elapsed time.
5, a kind of method of using for the camera that has first and second grades of shutter releases that continuous coverage is carried out in brightness may further comprise the steps:
When starting, measures by first order shutter release ambient brightness around object;
When the shutter release unstart of the second level, determine whether passed through a schedule time after the starting of first order shutter release;
By according to said definite result, measure ambient brightness continuously around object at each predetermined time interval; And
Brightness value according to the prestarting last measurement of second level shutter release comes the calculation exposure value.
6, in accordance with the method for claim 5, it is characterized in that, further comprising the steps of:
When first order shutter release started, sensing was contained in the light sensitivity of the egative film in the camera and measures the object distance;
Determine when the shutter speed minimum of crossing around the ambient brightness of object when low, and the shutter speed maximum when the ambient brightness that centers on object is too high, and measured brightness value is determined exposure value when hanging down only according to brightness is neither too high; And
With institute's definite exposure value picked-up photograph.
7, a kind of exposure value that is used for scanner-recorder is determined device, comprising:
Be used to write down the mechanism of subject image;
Be used for flash spotter that the light on the object is measured;
Be used to start the device of document image mechanism; With
Be used to start the device of flash spotter;
Wherein, the device that is used to start flash spotter starts flash spotter with the time interval of setting and comes light on the Measuring Object; And
Wherein, start for the first time at photometer and to be started with the time between the moment of record subject image with moment of the light on the Measuring Object and document image mechanism, flash spotter may start repeatedly.
According to the described device of claim 7, it is characterized in that 8, the mechanism of document image is a kind of photosensitive medium, and the device that starts document image mechanism is a shutter.
According to the described device of claim 8, it is characterized in that 9, shutter speed is to start the last photo measure of being done by flash spotter before according to shutter to determine.
According to the described device of claim 8, it is characterized in that 10, shutter speed is to determine according to start for the first time the mean value that carries out repeatedly photo measure between the time that flash spotter to shutter starts in order to write down subject image.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1019940010656A KR100236641B1 (en) | 1994-05-16 | 1994-05-16 | Continuous illuminent measuring apparatus and control method of a camera |
| KR94-10656 | 1994-05-16 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1144914A true CN1144914A (en) | 1997-03-12 |
Family
ID=19383152
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN95107106A Pending CN1144914A (en) | 1994-05-16 | 1995-05-16 | Successive brightness measuring device for camera and measuring method |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPH0850314A (en) |
| KR (1) | KR100236641B1 (en) |
| CN (1) | CN1144914A (en) |
| DE (1) | DE19517747A1 (en) |
| FR (1) | FR2719916B1 (en) |
| GB (1) | GB2289545B (en) |
| RU (1) | RU2134896C1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100518252C (en) * | 2006-09-29 | 2009-07-22 | 佳能株式会社 | Image sensing apparatus and control method |
| CN102137233A (en) * | 2009-11-20 | 2011-07-27 | 奥林巴斯映像株式会社 | Camera and light metering method for the same |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5087645A (en) * | 1973-12-05 | 1975-07-14 | ||
| JPS5468628A (en) * | 1977-11-11 | 1979-06-01 | Nippon Chemical Ind | Camera motor drive unit controller |
| JPS56167130A (en) * | 1980-05-27 | 1981-12-22 | Konishiroku Photo Ind Co Ltd | Automatic focusing camera |
| GB2169089B (en) * | 1984-11-21 | 1989-10-11 | Canon Kk | Camera |
| US4792820A (en) * | 1985-09-13 | 1988-12-20 | Minolta Camera Kabushiki Kaisha | Camera with automatic focus and exposure control means |
| US5191384A (en) * | 1988-01-30 | 1993-03-02 | Minolta Camera Kabushiki Kaisha | Distance measuring system |
| CA2127076A1 (en) * | 1993-07-01 | 1995-01-02 | Soon-Gil Seo | Brightness measuring device for a camera and related control method |
-
1994
- 1994-05-16 KR KR1019940010656A patent/KR100236641B1/en not_active IP Right Cessation
-
1995
- 1995-05-15 DE DE1995117747 patent/DE19517747A1/en not_active Withdrawn
- 1995-05-16 JP JP11672595A patent/JPH0850314A/en active Pending
- 1995-05-16 CN CN95107106A patent/CN1144914A/en active Pending
- 1995-05-16 FR FR9505772A patent/FR2719916B1/en not_active Expired - Fee Related
- 1995-05-16 RU RU95107896A patent/RU2134896C1/en active
- 1995-05-16 GB GB9509868A patent/GB2289545B/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100518252C (en) * | 2006-09-29 | 2009-07-22 | 佳能株式会社 | Image sensing apparatus and control method |
| CN102137233A (en) * | 2009-11-20 | 2011-07-27 | 奥林巴斯映像株式会社 | Camera and light metering method for the same |
| CN102137233B (en) * | 2009-11-20 | 2014-09-03 | 奥林巴斯映像株式会社 | Camera and light metering method for the same |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2289545A (en) | 1995-11-22 |
| RU95107896A (en) | 1997-05-10 |
| KR950033632A (en) | 1995-12-26 |
| FR2719916A1 (en) | 1995-11-17 |
| GB9509868D0 (en) | 1995-07-12 |
| DE19517747A1 (en) | 1995-11-23 |
| GB2289545B (en) | 1997-12-10 |
| KR100236641B1 (en) | 2000-01-15 |
| FR2719916B1 (en) | 1998-01-30 |
| RU2134896C1 (en) | 1999-08-20 |
| JPH0850314A (en) | 1996-02-20 |
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