JPH0713722B2 - camera - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called active superimpose display for adjusting the amount of emitted light, which superimposes on a light image in a finder and displays information by using emitted light.

[Conventional technology]

2. Description of the Related Art Conventionally, it has been widely practiced to display photographing information such as a shutter speed, an aperture value, a focused / non-focused state of automatic focus adjustment, on the outside of a field of view of a camera. At this time, a method is known in which the brightness of the optical image in the field of view of the finder is detected, and the display device is brightness-modulated to have brightness substantially equal to the brightness to emit light, thereby forming information display that is easy for an observer to see.

For example, as shown in FIG. 9, a camera display device having a TV (shutter time) display LED row 112, an AV (aperture value) display LED row 113, and a focus state display LED 114 is provided outside the finder observation field of view 111. Are known. Reference numeral 115 is a field frame for automatic focus adjustment. In the display device of such a camera, it is desirable to perform the brightness modulation based on the average brightness of the entire finder field 111 as in JP-A-60-83995 proposed by the present applicant. On the other hand, when the brightness of the finder light image is measured by a method such as partial metering which has a specific sensitivity in the central part, when the part happens to have a particularly bright or dark light amount distribution, the display light emission amount becomes too large. Or
It's too small and hard to see. This is because the display position is outside the field of view of the finder, and the observer's eyes are viewing the display light while reacting to the overall brightness of the finder light image.

[Problems that the invention is trying to solve]

However, the present inventors have found that the brightness modulation photometric value should be based on a methodology different from the conventional method when the display unit is in the finder field.

As an example of the display in the field of view of the finder, there is a multi-point distance measuring point display as shown in FIG. A focus adjustment device capable of performing focus detection at a plurality of different positions within a shooting screen is known. In the simplest case, a plurality of conventionally used focus detection devices may be arranged in parallel, and one of the detection results may be selected by some method to adjust the focus. Further, various focus detection devices suitable for providing a large number of distance measuring points have already been proposed. In such a case, when the focus is selectively adjusted at a plurality of different positions, it is greatly affected on the operability in use to clearly indicate to which distance measuring point the focus should be adjusted. Although there are various configurations of the display method shown in FIG. 10, in one embodiment to be described later, a display pattern formed by the integration of the microprisms by locally illuminating the microprisms engraved on the matt surface with an LED or the like. The light is apparently emitted. One of the visual field frames 121, 122, 123 corresponding to the selected focus detection point apparently emits light.

Since the distance measuring point display described above is observed by being superposed on the finder light image, it has been found as a result of the study that the local brightness of the finder light image at the display position greatly affects the visibility of the display light. Especially when the finder light image at the display position is brighter than the average brightness, the tendency is remarkable, and the visibility of the display light is predominantly determined by the local brightness. On the other hand, when the finder light image at the display position is darker than the average brightness, the average brightness of the finder is a factor that determines the brightness of the display light that is easy to see.

That is, when performing localized light emission display by superimposing on the finder light image, the luminescence amount is calculated from the local photometric value of the brightness of the light image near the display position and the photometric value of the overall brightness of the finder. If you do not do this, you will not always be able to obtain a clear display in a wide range of shooting scenes. The conventionally known technology has not been sufficiently aware of this point, and thus has a serious problem in practical use.

[Means for Solving Problems] (1) A camera having a finder in-field display device that superimposes on an optical image in the finder field of an optical finder for confirming a shooting screen and displays information by light emitted from a light-emitting element. And a second photometric means for partially photometrically measuring a display vicinity area including a display position of the display device in the viewfinder field, and a second photometric means for measuring a wider area than the first photometric means in the viewfinder field. A camera provided with photometric means, a computing means for computing a light emission control value based on the photometric outputs of the first and second photometric means, and a drive circuit for controlling the light emission amount of the light emitting element based on the output of the computing means. Is characterized by.

Further, the calculating means is characterized by a camera that compares the photometric value of the first photometric means with the photometric value of the second photometric means and calculates the light emission control value based on the comparison result.

Further, the information display is characterized by a camera which indicates the position of the focus detection point of the focus detection device.

[Examples] Examples of the present invention will be described below.

FIG. 1 is a circuit diagram showing an embodiment of a camera equipped with a display device according to the present invention.

In the figure, PRS is a camera control device, for example, a one-chip microcomputer having a CPU (central processing unit), ROM, RAM, and A / D conversion function inside. Controller PRS
Performs a series of camera operations such as automatic exposure control function, automatic focus adjustment function, film winding / rewinding, etc. according to the camera sequence program stored in ROM. For that purpose, the control device PRS uses the communication signals SO, SI, S
CLK and communication selection signals CLCM, CSDR, CDDR and CLDDR are used to communicate with the peripheral circuits in the camera body and the control device in the lens to control the operation of each circuit and lens.

SO is a data signal output from the control device PRS, SI is a data signal input to the control device PRS, and SCLK is a synchronous clock of the signals SO and SI.

LCM is a lens communication buffer circuit, which supplies power to the lens power supply terminal VL while the camera is operating, and the selection signal CLCM from the control device PRS is at a high potential level (hereinafter abbreviated as “H”, low potential level). (The level is abbreviated as "L")
In the case of, the communication buffer between the camera and the lens becomes available.

The control device PRS sets the selection signal CLCM to "H", and the communication signal S
When the specified data is sent from the communication signal SO in synchronization with CLK, the buffer circuit LCM receives the buffer signals LCK and DCL of the communication signals SCLK and SO via the camera-lens communication contact.
Is output to the lens. At the same time, the signal DL from the lens
The buffer signal of C is output to the communication signal SI, and the control device PRS
Inputs lens data from SI in synchronization with the communication signal SCLK.

SDR is a drive circuit of the line sensor device SNS for focus detection composed of CCD, etc., which is selected when the signal CSDR is "H" and uses the communication signals SO, SI, SCLK to control the device PRS.
Controlled by. Signals CK are clocks for driving CDD φ1, φ2
The signal INTEND is a signal for notifying the control device PRS that the accumulation operation is completed.

The SNS is a photoelectric conversion unit of a so-called image shift detection focus detection device. The photoelectric conversion unit SNS has three series of pairs of sensor rows connected in series in the array direction and generates photoelectric signal rows corresponding to three distance measuring points. That is, the sensor rows corresponding to the distance measuring point 1 are SA1 and SB1, and the sensor rows corresponding to the distance measuring point 2 are
SA2 and SB2, the sensor rows corresponding to the distance measuring point 3 are SA3 and S
It is B3. The focus detection light image incident on the sensor array pair at each distance measuring point may be considered to be formed by separate separator lenses or may be considered to be formed by a pair of common separator lenses. A method for realizing this function is publicly known or has been proposed by the present applicant and is not related to the gist of the present invention, and therefore detailed description thereof will be omitted. Further, the number of distance measuring points in the present embodiment does not limit the present invention. Also, the method of focus detection is not limited to the present invention, and can be implemented by using blur detection, for example.

The output signal OS of the photoelectric conversion unit SNS is a time-series image signal in which the clocks φ1 and φ2 are synchronized, and after being amplified by the amplifier circuit in the drive circuit SDR, it is output to the control device PRS as the signal AOS. The control device PRS inputs the signal AOS from the analog input terminal and, in synchronization with the signal CK, sequentially stores it as a digital signal in a predetermined address of the RAM by an internal A / D conversion function.

Similarly, SAGC, which is the output signal of the photoelectric conversion unit SNS, is the output of the AGC (Auto Gain Control) sensor in the photoelectric conversion unit SNS and is input to the drive circuit SDR to control the accumulation of the photoelectric conversion unit SNS. Used for.

SPC1 to SPC4 are photometric sensors that receive light from a subject through a taking lens. The output group SSPC is the control device PRS
It is input to the analog input terminal of and is used for automatic exposure control and brightness modulation of display in the finder according to a predetermined program after AD conversion. The output of each sensor SPC is logarithmically converted by the logarithmic compression diode D, converted into low impedance by the operational amplifier, and input to the control device PRS. FIG. 2 shows a photometric area division pattern of four SPCs. A condenser lens is arranged behind the pentaprism and above the eyepiece, and a patterned SPC plate is provided behind it, and the focus plate and the SPC plate are placed in a substantially image-forming relationship. The SPC pattern of this embodiment is an image of the finder field 11
There is a photometric sensor SPC4 for average photometry, slightly inside 1 ',
Further, inside thereof, photometric sensors SPC1, SPC2, SPC3 for spot photometry centering on the positions of three focus detection points are placed.

DDR is a switch detection and external display circuit, signal CDD
It is selected when R is “H” and controlled by the controller PRS using the signals SO, SI, SCLK. That is, the display of the display member DSP of the camera is switched based on the data sent from the control device PRS, and the on / off states of various operation members of the camera are notified to the control device PRS by communication.

LDDR is the information display circuit inside the finder, and it is the signal CLDDR.
Is "H", it is selected and controlled by the control device PRS using the data signals SO and SI and the synchronous clock SCLK. That is, the display of TLED for TV display, ALED for AV display, AFLED for focus display and LED1, LED2, LED3 for selective focus detection point display is switched based on the data sent from the control device PRS.

SW1 and SW2 are switches interlocked with a release button (not shown). SW1 is turned on when the release button is pressed in the first step, and subsequently SW1 is turned on when the release button is pressed in the second step. The control device PRS performs photometry and automatic focus adjustment when SW1 is turned on, and exposure control and film winding are performed when SW2 is turned on.

SW2 is connected to the "interrupt input terminal" of the control device PRS, which is a microcomputer, so that even if the program is executed when the switch SW1 is on, an interrupt is generated by the switch SW2 being on, and control can be immediately transferred to a predetermined interrupt program.

MTR1 is a film feeding motor, MTR2 is a motor for mirror up / down and shutter spring charge, and forward / reverse control is performed by respective drive circuits MDR1 and MDR2.
Signals M1F and M1 input from controller PRS to MDR1 and MDR2
R, M2F, M2R are signals for motor control.

MG1 and MG2 are magnets for starting the leading and trailing curtains of the shutter, respectively, and are energized by signals SMG1 and SMG2 and amplification transistors TR1 and TR2, and the shutter control is performed by the control device PRS.

The switch detection and display circuit DDR, the motor drive circuits MDR1 and MDR2, and the shutter control are not directly related to the present invention, and thus detailed description thereof will be omitted.

A signal DCL input to the in-lens control device LPRS in synchronization with the clock LCK is command data from the camera to the lens FLNS, and the operation of the lens in response to the command is predetermined. The lens LPRS analyzes the command according to a predetermined procedure, and performs the operations of focus adjustment and diaphragm control, the operation status of each part of the lens from the output DLC (drive status of the focus adjustment optical system,
Aperture drive status etc.) and various parameters (open F number,
The focal length, the amount of defocus and the coefficient of the amount of movement of the focus adjustment optical system, etc.) are output.

In the embodiment, an example of a zoom lens is shown, and when a focus adjustment command is sent from the camera, the focus adjustment motor LMTR is signaled according to the drive amount and direction sent at the same time.
Driven by the LMF and LMR, the optical system is moved in the optical axis direction for focus adjustment. The moving amount of the optical system is the encoder circuit
It is monitored by the pulse signal SENCF of ENCF and is counted by the counter in the control device LPRS, and when the predetermined movement is completed, the control circuit LPRS itself sets the signals LMF and LMR to "L" and the motor LMT.
Braking R.

Therefore, once the focus adjustment command is sent from the camera, the camera control device PRS does not need to be involved in lens driving at all until the lens driving is completed. Also, the contents of the counter can be sent to the camera when requested by the camera.

When a diaphragm control command is sent from the camera, a stepping motor DMTR known for driving the diaphragm is driven in accordance with the number of diaphragm stages sent at the same time. Since the stepping motor can be open-controlled, it does not need an encoder for monitoring the operation.

ENCZ is an encoder circuit attached to the zoom optical system,
The control device LPRS sends the signal from the encoder circuit ENCZ to SENCZ.
Enter to detect the zoom position. The lens parameter at each zoom position is stored in the control device LPRS, and when there is a request from the control device PRS on the camera side, the parameter corresponding to the current zoom position is sent to the camera.

The information display device in the finder of this embodiment is as shown in FIG. That is, a TV display composed of 7-segment LED 1
12, an AV display 113, an in-focus display LED lamp 114, and three distance measuring point displays 121, 122, 123. Distance measuring point display 121,122,1
23 is formed by forming fine prisms in a display shape on the focusing plate mat surface, and the cross section of the focusing plate is enlarged as shown in FIG. That is, the fine prisms 33 are formed on the mating surface 32 side of the focusing plate 31. A Fresnel lens 34 is formed on the opposite side of the focusing plate 31. In a normal state, the image-forming light flux that enters the photographing lens, is reflected by the main mirror, and reaches the focusing plate is refracted and scattered by the fine display prism 33, and is deflected so as not to enter the pupil of the observer. Only the part where the prism is formed looks dark by the principle of Shuriren. Therefore, the prism formation pattern is recognized as a black display by the observer. However, when the illumination light 35 is emitted from an illumination light source LED (not shown) at a predetermined angle, it is deflected by the fine prism 33 and advances in the direction of the arrow 36, that is, in the direction perpendicular to the focusing plate surface, so that it enters the observer's pupil. The direction of the light rays becomes normal, and the prism forming portion appears to emit bright light in the color of the illumination light. An illumination light source is provided for each of the plurality of focus detection area display units, and local illumination is performed for each of the focus detection area display units, so that one focus detection area display prism can independently emit light. Incidentally, the illumination light incident on the mat portion that is not the fine prism forming portion is diffused by the mat surface and becomes the angle distribution of the arrow 37, and since this angle does not reach the roof surface of the pentaprism, it does not reach the observer's pupil. Do not fit.

FIG. 4 shows an optical arrangement around the penta prism 41.

The display illumination light 35 emitted from the illumination light source LED is partially deflected by the fine prism on the upper surface of the focusing plate 31 and emitted to the roof surface 41b of the pentaprism. Unnecessary illumination light is ray 45
Next, it is absorbed by the minor surface 41a of the pentaprism.
In the figure, 42 is a diopter lens, 43 is a photometric condenser lens, and 44 is a photometric sensor.

The basic operation of this embodiment will be described with reference to the flow chart of FIG. After the switch SW1 is closed on the first stroke of the shutter release button and the electric circuit system of the camera is turned on, the AE subroutine and the AF subroutine are alternated according to the program stored in the ROM in the controller PRS. Be called. The conceptual flow and calculation method of the AE subroutine are shown here.

When the AE subroutine is called, the output values of the four photometric SPCs are sampled and held at step (001),
AD conversion is performed at step (002). The exposure control mode is detected at step (003), and if it is the automatic exposure mode, the process branches to step (004). Step (004) detects data such as lens open F value required for automatic exposure calculation through communication with the lens control device LPRS, and step (005) detects set values for TV, AV, etc. (00
Perform automatic exposure calculation in 6). Details of the automatic exposure calculation are omitted because they are not the subject of the present invention.

In step (007), TV display 112, A outside the field of vision
The amount of light emitted from the LEDs of the V display 113 and the focus display 114 is calculated. This calculation method is publicly known. For example, the LED light duty cycle η may be obtained as a function of η = η (BV ₄ ) (1) using the BV ₄ signal output from the sensor SPC4 that covers most of the screen. As η, for example, the sixth
As shown in Fig. 6 (a), a constant BV value BVa or less and BVb or less is set as a constant, and the range of BVb>BV> BVa is continuously varied. Stepwise function as shown in Fig. 6 (b) It is used by the one simplified by. In the case of the display outside the visual field, the photographer views the display while reacting to the brightness in a relatively wide range of the finder visual field, and therefore it is not preferable to control the display light emission amount by the locally focused photometric value. In this example, the sensor SPD4
It is desirable to control by the photometric value mainly based on, and the sensors SPC1 to SPC3 are used even if they are used. In the next step (008), the out-of-field LED is calculated based on the calculated LED emission value.
Control the display device. In this embodiment, the signal CLDDR is set to the H level to change the information display circuit LDDR in the finder.
Select, and send the display value and light emission value of the TLED for TV display and the ALED for AV display by the data signal SO from the control device PRS to the display circuit LDDR, and the display circuit LDDR converts the received data. Based on this, the display LED is controlled to emit light.

In step (009), which of the three focus detection points is the focus adjustment target is detected. The selection of the focus detection points may be manual or automatic. For example, an automatic selection method for selecting a focus detection point having an object at a position closest to the camera is known. Since the AF point selection has already been made in the AF subroutine, this step is detected by referring to the contents of the flag set by the AF subroutine. In the next step (010), the LED emission amount of the display in the field of view of the finder is calculated. In this case, unlike the case of the display outside the visual field, the outputs of the sensors SPC1 to 3 are positively used. One calculation method in this embodiment is as follows. BV of sensor SPC1-4
If the values are BV ₁ to BV ₄ , and the selected AF point is AF point 1, BVX = max (BV ₁ , BV ₄ ) (2a) η = η (BVX) (2b) Calculate the amount of light emission. That is, as the photometric value for calculating the light emission amount, the partial photometric value BV ₁ near the focus detection point and the photometric value BV _{4 of the} entire screen are compared, and the larger one BVX is used. After that, the emission duty cycle of LEDs 1 to 3 is determined using BVX. At this time, the calculation method of the expression (2b) may be the same as that of the expression (1) or the sixth illustration. But BV ₁ and B
As a result of examination, it has been found that when the V ₄ is extremely different, it is slightly difficult for the finder to see. It is more desirable to determine the light emission amount from both the partial photometric value and the average photometric value by the above method. The weighting ratio between BV ₁ and BV ₄ is α> β when BV ₁ > BV ₄ , and α <β when BV ₁ <BV ₄ . Further, as an extremely simplified structure, the effect of the present invention can be achieved even in the brightness modulation based on only the partial photometric value.

It should be noted that the equation (2b) relating the photometric value and the light emission amount is not exactly a linear change, but it is desirable that the expression (2b) changes exponentially as shown in FIG.

[Other Examples]

The present invention is also useful in a camera equipped with only one focus detection device as shown in FIG. The range-finding frame display of a single-lens reflex camera that has a focus adjustment function has been
Black display, which applies the light-scattering effect of micro prisms, is often used, but this type of display device is difficult to see when the finder is dark, so it is easy to use when illuminated in dark conditions.
Further, the function of the in-focus display lamp 114, which is conventionally provided outside the field of view of the finder, can be replaced by the light emission of the focus detection area display. For example, if the electrical flow is configured so that the focus detection point blinks gently during focus adjustment operation, lights up continuously when focusing is detected, and blinks at a rapid cycle when focus detection is not possible, the subject optical image is displayed. It is possible to realize a very easy-to-use camera because the focus state of the camera can be visually confirmed by superimposing it while observing with the finder. Even in this case, the present invention in which the display light emission amount is determined by using the partial photometric value around the display section is extremely effective. Conventionally, as a photometric device for a camera having one distance measuring point, it has been proposed by the present applicant to have a sensor SPC pattern in which a finder field is divided into six as shown in FIG. 8, for example. Logarithmically compressed B
Taking the average of the V output gives a nearly averaged photometric value. On the other hand, since the spot photometric sensor SPC81 and the partial photometric sensor SPC82 are arranged at the center of the screen, the BV _81-86 values of these sensors SPC81-86 and the above average measured value are used to _{obtain the} equations (2) and (3). The display emission value is obtained from the calculation based on the above. For example, in the case of the focus detection area display 130, BVX = max (BVX
₈₁ , BV _81-86 ), and in the case of distance measuring point display 132,
BVX = max (BV ₈₂ , BV _81-86 ).

In addition, when the focusing state is also displayed by the apparent light emission of the distance measuring point display in this way, it is easy to understand if two or more light sources of different colors are used and the illumination color is selectively used depending on the operating state of the focus adjustment device. Is obtained. For example, it is possible to use different colors such as orange during the focus adjustment operation, green when the focus is achieved, and red when the focus cannot be detected. Also in this case, the method of adjusting the light emission amount according to the brightness of the subject light image and its light amount distribution is effective.

INDUSTRIAL APPLICABILITY The present invention is effective for general devices that display information by superimposing it on a light image in the field of view of a finder by light emission. Even if the display device does not use the refraction of the micro prism,
For example, a reflection type of a micro prism may be used, or a type in which a light emitting substance such as electroluminescence is inserted into a finder optical system may be used. Further, the type of display information is not limited to the focus detection point display, and for example, even if it is TV, AV display or various warning displays,
The present invention can be effectively used as long as it is locally localized and has a photometric means for obtaining a partial photometric value in the vicinity of the position.

In the case of the distance measuring point display,
It is possible to substitute the output value of the focus detection sensor. Normally, the photometric sensor outputs a logarithmic compression to increase the latitude, but the focus detection sensor has a linear output, so some of the following measures are required. The output of the array of focus detection sensors (for example, SA1 in FIG. 1) is Ai.
The output of the sensor array consists of N pixels SA1 is A _1, ... A
_It shall consist of _N time series outputs. Take the sum of N pixels Is the photoelectric output of the virtually connected sensor,
A value obtained by _dividing this by the storage time T _int is proportional to the amount of light incident on the entire area of the sensor array SA1 = A _o / T _int (5) If this value is logarithmically or digitally converted, A photometric value that equivalently regards the detection sensor SA1 as a photometric sensor is obtained.

When the partial photometric value is obtained from the output of the focus detection sensor, the present invention can be implemented without a dedicated partial photometric sensor, which is advantageous. Particularly, in the case of distance measuring point display, since the focus detection sensor is located at a position equivalent to the display position, it is well matched with the present invention.

〔The invention's effect〕

As described above, according to the present invention, various information displays which are superposed on the finder visual image and are displayed as light emission always have appropriate brightness regardless of the brightness of the optical image in the finder visual field and its light amount distribution, and are easy to see. A camera display device is obtained. Further, according to the present invention, the display is improved, so that the operability of the automatic function such as the automatic focus adjustment function of the camera is remarkably improved, and the camera can be easily configured.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a camera according to an embodiment of the present invention. FIG. 2 is a photometric division pattern of the camera of the embodiment of the present invention. FIG. 3 shows a display element of a camera according to an embodiment of the present invention. FIG. 4 is an optical path diagram of the display system of the camera of the embodiment of the present invention. FIG. 5 is a flow chart of the camera of the embodiment of the present invention. FIG. 6 shows an example of the brightness calculation method of the camera of the embodiment of the present invention. FIG. 7 shows an example of the brightness calculation method of the camera of the embodiment of the present invention. FIG. 8 is a photometric division pattern according to another embodiment of the present invention. FIG. 9 shows a display in the finder of a conventionally known camera. FIG. 10 is a display in the finder of the camera according to the embodiment of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Keisuke Aoyama, 770 Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon Inc., Tamagawa Plant (72) Kenji Ito, 770, Shimonoge, Takatsu-ku, Kawasaki-shi, Kanagawa Canon Inc. In Tamagawa Works (56) Reference JP 62-141864 (JP, A) JP 62-129830 (JP, A) JP 62-43346 (JP, U) JP 62-46184 (JP, Y2)

Claims (3)

[Claims] 1. A camera having a viewfinder display device for displaying information by light emitted from a light-emitting element, which is superposed on a light image in a viewfinder field of an optical viewfinder for confirming a shooting screen. First photometric means for partially photometrically measuring a display vicinity area including the display position of the display device; second photometric means for photometrically measuring an area wider than the first photometric means within the viewfinder field; A camera comprising: a calculation unit that calculates a light emission control value based on a photometric output of a second photometric unit; and a camera that includes a drive circuit that controls a light emission amount of the light emitting element based on an output of the calculation unit. 2. The calculating means compares the photometric value of the first photometric means with the photometric value of the second photometric means, and calculates the light emission control value based on the comparison result. The camera according to claim 1. 3. The camera according to claim 1, wherein the information display indicates a focus detection point position of the focus detection device.