JPS6262231A - Multi-point photometer - Google Patents

Abstract

PURPOSE:To obtain a multi-point photometer effective for cameras, by arranging a multi-split photometry circuit, an automatic focus adjusting means, a means for determining a brightness distribution end value, a means for outputting latitude information of a film and a means for judging on whether the brightness distribution irrelevant to the decision on exposure level is increased depending thereon. CONSTITUTION:An So is turned on by the operation of a switch and a photometry circuit 13 starts to send brightness signal in areas of an object field to a CPU. With the closing of a switch S1, an automatic focus detecting circuit 14 operates by a signal of the CPU to perform a focusing on an object ad when the object gets, in focus, it sends an adjustment ending signal to a processor interrupt mechanism via a gate 23 to disable a focus adjustment. Then, the CPU processes the brightness signal to judge on whether the deviation of the maximum and minimum brightness of the object field from a reference value is within a specified value determined by latitude of a film used on the brightness of the object field portion containing an area used by the automatic focus detection mechanism for measuring distance as reference to determine the exposure level to ensure that the brightness range of the object field portion will meet the latitude of the film used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photometry device for determining an appropriate exposure amount in a camera or the like.

[Conventional technology]

Various methods have been proposed for determining the exposure amount of a camera, etc., in which the exposure amount is determined based on the luminance signals (2) obtained from each of the luminance signals obtained by photometering multiple parts of the subject. One that determines the exposure amount from the average value, median value, or mode of the signal, one that determines the exposure amount based on a value obtained by shifting the maximum or minimum value of multiple luminance signals by about half the film latitude, There is one that determines the exposure amount from the average value of the maximum value and minimum value of the brightness signal.

Furthermore, according to Utility Model Publication No. 60-11475, the field is divided into multiple regions to obtain multiple luminance signals, the average value of these is determined, and this average value is compared with the luminance signal in each region. Then, by normalizing the brightness in each divided area and performing a baton analysis, the exposure amount is determined from the relationship between the baton and the appropriate exposure amount, which has been experimentally and empirically obtained.

[Problem to be solved by the invention] The above-mentioned device can identify the brightness distribution of the entire field,
This configuration is intended to determine a more appropriate exposure amount than determining the exposure amount by simple average photometry or spot photometry. However, even with these devices, whether or not the exposure amount is determined appropriately is ultimately a matter of probability, and even if this probability becomes higher, the exposure amount will still be determined as intended by the photographer. There remains some uncertainty as to whether this is the case.

SUMMARY OF THE INVENTION An object of the present invention is to provide a multi-point photometry device for a camera that can determine an exposure amount while accurately reflecting both the photographer's intention and the luminance distribution of the entire object scene.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention adopts as a reference value a signal corresponding to a luminance part that must correspond within the film latitude width among a plurality of photometric signals, and also corresponds to the maximum luminance part (simply the maximum luminance part or the maximum luminance part after removing excessive luminance part, meaning the maximum luminance part among the effective luminance parts as the object of consideration) and the minimum effective luminance part Each photometric signal is determined as a luminance distribution end value, and information regarding film latitude is also taken into account. Then, based on the information regarding these reference values, brightness distribution edge values, and film latitude, the above reference values or
The exposure amount is determined in accordance with the value corrected within the limit where this reference value remains within the film latitude width.

This will be explained with reference to FIG. 1, which corresponds to an embodiment configured using a multi-segment photometry device as an example. 1 is a photoelectric conversion element that divides the field into multiple regions and measures the brightness of each region. , 13 is a photometry circuit for automatic exposure control that A/D converts the output signal of the photoelectric conversion element and sends it to the processor 15;
10 is an automatic focus detection element, 14 is an automatic focus detection circuit that processes the output signal of the automatic focus detection element to operate the focus adjustment mechanism, and 15 is a photometry circuit 13 for automatic exposure control, which processes signals from the automatic focus detection circuit. The processor determines the appropriate exposure amount, So, S2 is the operation switch. , So, and S2 are arranged and operated by one operation unit.

Now, when I operate the operation switch, the first thing I do is S. The photometry circuit 13 is activated and the brightness signals of each area of the field are sent to the processor 15. Next, S enters, and the automatic focus detection circuit 14 is activated by a signal from the processor to focus on the subject. When the in-focus state is reached, a focus adjustment completion signal is sent to the interrupt mechanism of the processor via the gate 23. , disables the automatic focus adjustment mechanism. After this, the processor processes the luminance signal of the subject that was captured earlier, and uses the luminance of the part of the subject including the area used by the automatic focus detection mechanism for distance measurement as a reference value, which is the highest value in the subject. It is determined whether the deviation from the reference value of brightness and minimum brightness is within a predetermined value determined by the latitude of the film used, and based on the result, the automatic focus detection mechanism detects the subject including the area used for distance measurement. The exposure amount is determined so that the brightness of the field area falls within the latitude of the film used.

[For production]

First, a signal corresponding to a luminance portion that must fall within the film latitude width is adopted as a reference value. (Specifically, this can be done, for example, by having the photographer decide on the composition and perform photometry so that the luminance portion falls within a specific photometry value range where the odor is determined in advance in multi-segment photometry.

In this case, if you make the above-mentioned specific photometry area correspond to the area to be auto-focus adjusted, the auto-focusing operation will unconsciously adjust the composition. In a single light-receiving element type spot photometer that measures light while aiming at areas in sequence, the same effect can be obtained by configuring it to use the photometric value of the first brightness area as the reference value, for example. ) Basically, the exposure amount is determined by this reference value, but based on the reference value, the brightness distribution end value, and the information about the film latitude, each brightness portion between the two brightness distribution end values is determined as much as possible. The exposure amount is corrected as necessary to keep it within the film latitude. At this time, it is important that the above-mentioned correction is performed within the limit where the reference value remains within the film latitude of C2.Example: Examples of the present invention will be described below.

(1) Overview of Configuration FIG. 1 is a block diagram schematically showing an automatic exposure and automatic focus control device for a camera incorporating the photometric device of the present invention.

In the figure, 1 is a photoelectric conversion element that divides the field into multiple regions and measures the brightness of incident light for each area, and 13 is an automatic exposure that processes the output signal from the photoelectric conversion element 1 and converts it from A/D. A control photometry circuit (hereinafter referred to as AE), 10 an automatic focus detection element, 14 an automatic focus detection circuit (hereinafter referred to as AF) that processes the output signal of the detection element 10, 15 an input from the automatic exposure control photometry circuit and others. There is a processor (hereinafter referred to as CPU) that processes signals, determines the exposure amount, etc., and instructs each control mechanism to operate, and 16 is a read-only memory (16) that stores lens-specific information such as the lens's F number and focal length. (hereinafter referred to as ROM), 17 is a signal processing circuit for displaying the photographing conditions etc. as a result of processing by the CPU on the outside of the camera, and 18 is an automatic control circuit for controlling the exposure mechanism of the camera based on the appropriate exposure signal output from the CPU. An exposure control unit (hereinafter referred to as AE control), 19 an automatic focus control unit (hereinafter referred to as AF control) that controls the focus control mechanism of the camera based on a focus control signal output from the CPU, and 80% 51sS2 installed in the camera; With the operation switches, one common operation section is used to sequentially select photometry SO1 autofocus S11 release S
Switch 2 is turned on. 23 is a gate circuit, and 24 is a setting section for predetermining exposure conditions and the like for the camera.

FIG. 2 shows how the field is divided into a plurality of regions and the photoelectric conversion elements 1 are arranged in each region in order to measure the brightness of the field and its distribution state.

FIG. 3 is a cross-sectional view showing the photometric device of the present invention incorporated into a camera. The light incident on the lens system 2 is reflected by the main mirror 4, passes through the upper condenser lens 5 and intersolism 6, further passes through the nof prism 7 and relay lens 8, and then reaches the photoelectric conversion element 1 arranged above it. The incident image is formed on. . Further, the light transmitted through the semi-transparent part formed at the center of the mirror 4 is reflected downward by a sub-mirror behind the mirror 4, passes through the relay lens 9, and enters the detection element 10 for automatic focus detection. Note that this detection element 10 is the fifth
The in-focus state of the center of the field of view shown in the figure is detected. Also, 3 is the aperture, 11 is the shutter curtain, 12 is the film surface, 1
Reference numeral 9 indicates an automatic focus control section (hereinafter referred to as AF control).

FIG. 4 shows in slightly more detail the circuit configuration between the operation switch section, AE section, AF section and CPU in the block diagram shown in FIG. 1.

The operation switch part is a common operation part, and the photometry switch 5
0s auto focus switch 51. The Ll-'s switch S2 can be turned on in this order. Photometering switch SO
When turned on, 2 signals are sent to the CPU via the gate circuit.
Two interrupt signals, 1NT1 and INT2, are sent and processed by the interrupt mechanism within the CPU, but it is also possible to disable interrupts using an interrupt disable signal from the CPU.

The automatic exposure control photometry circuit 13 receives an A/D conversion start signal ADSTR% A/D conversion clock pulse A from the CPU side.
It receives four types of input signals: DCP1 reference clock signal ξ SCK1 data read signal AESTR, and sends the brightness information of the object field processed in AE to the CPU as serial data. Note that the luminance information sent as serial data from the AE is converted into a normal ξ parallel signal by a serial root ξ parallel conversion section (SP conversion section) within the CPU.

Automatic focus detection circuit (AF) 14 is the AF from the CPU side.
It receives a start signal, an AP stop signal, and a chip select signal C8 used for data read control, and sends an automatic focus detection end signal AFE to the gate circuit connected to the photometry switch So, and also sends display data to the CPU side. .

(2) AE Section FIG. 5 shows the circuit configuration of the AE section which processes the signal from the photoelectric conversion element, A/D converts it, and sends it to the CPU. below,
This circuit and its operation will be explained.

The output signals of the photoelectric conversion elements PD, -PD, arranged in each of the plurality of divided object fields are logarithmically compressed by the amplifier A□-As to obtain brightness values BVo to BV8.

Among the obtained brightness values BVO-BVB, the brightness value BV in the center of the field is used as the reference value, and the brightness value BV in other areas
By processing I-BVB as a difference including the sign from the reference value, it is possible to recognize the brightness distribution of the entire field with the center of the field as a reference. Therefore, the brightness value BV o of the central part of the field is converted into an 8-bit signal by the A/D converter ADo, and the reference value BV is also converted.

The brightness values BV and -BVB of the other areas are input to the connosolators CPt to CP8 to obtain the positive and negative signs, and the (BVi - BVo) value (where i = 1 to 8)
is converted into a total of 6 bit signals consisting of 5 pits and a code pit using A/D converters AD, -ADs.

Each A/D converter has a data register that temporarily stores the data after conversion, and is selected by the signal CSo-C3s issued from the P/S control section to send it to the CPU as serial data. The contents are sent from the data register to the P/S control unit as an 8-pit parallel signal to the pass line. The P/S control section converts the parallel signal received from the pass line into a serial signal and sends it to the CPU. Details of the P/S control section will be explained later based on FIG. 9.

Note that the logarithmic compression amplifier A used in FIG.
As exemplified in FIG.
, a compression diode 28, and a level conversion buffer 29.

(3) A/D conversion section FIG. 7 shows an A/D converter ADo shown in FIG.

This shows the circuit configuration of ADi (i = 1 to 8). Figure 7 (a) shows AD, and Figure 7 (b) shows AD.
Indicates l. Since AD2 to AD8 have exactly the same configuration, they have been omitted.

A/D conversion means are basically the same for ADO and AD1 to AD8, and a double integration method is adopted. That is, first, a luminance value input as an analog quantity is charged into an integrating capacitor for a certain period of time. In this case, the charging current changes depending on the magnitude of the brightness value, so the charge after being charged becomes an integral value of the brightness value. Next, this is discharged under a constant current, and the discharge time is counted using a clock, Fruss, etc., and the sum of the Nockles numbers indicates the brightness value.

To briefly explain the circuit configuration of oil 0, an input signal of the brightness value BVo is input to one of the switching elements 200.

Further, two types of reference level signals Vstd1Vrefo are supplied from the power supply circuit 300, and the reference level signal Vstd1Vrefo is supplied from the power supply circuit 300.
fo is input to the other side of the switching element 200, and the reference level signal Vstd is supplied to the first input side of the operational amplifier 120. The output side of the switching element 200 is connected to the second input side of the operational amplifier 120 via a resistor R. An integrating capacitor C is connected between the output side and the second input side of the operational amplifier 120, and a switching element 201 is connected parallel to this. operational amplifier 1
The output of the converter 20 is input to the first input side of the converter 121, and the reference level signal Vst, d is input to the second input side of the converter 7. Con7zoreta 121
The signal is input to the control input side of the output bus switching element 201, the gates 202 and 203, and the flip-flop 204 to the control input side of the latch 31.

Further, the A/D conversion circuit is provided with a counter 30 that counts the charging/discharging time of the integrating capacitor C, and a latch 31 that holds the counted contents. From the CPU side, A/
The D conversion clock pulse ξ ADCP is supplied to the counter 30's G side (counting input side) via the gate 211, and the A/D conversion start signal ADSTR is supplied to the R side (reset signal side) of the counter 30. Supplied.

The ADD counter 30 is used not only as a counter for A/D conversion of input brightness value BVo, but also as a counter for A/D conversion of brightness values BV1 to BV8 that are A/D converted in AD1 to ADB.

Next, the operation of the circuit will be explained. First, the reference signal V
It is assumed that std is also smaller than the input brightness value BVo, and that the counter 30 is in a reset state. At this time, the output of the gate 205 is in the L# state. The output of the game) 205 is "H" when the contents of the counter 30 are hexadecimal numbers other than oooH to 0FFH. In other words, the counter 30 has been reset! 11.A
When the DSTR signal is input, the output of the gate 205 is L# and sb, and the switching element 200 is at the seventh
It is set to the state shown in Figure (a).

The input brightness value BV is input to the operational amplifier 120 via the switching element 200 and the resistor R, and the difference from the reference signal Vstd input to one of them is output. This difference signal is then input to the connominator 121 and compared with one of its inputs, Vstd.
When , the output of the converter 7 and the converter 121 is set to "H". At this time, the switching element 201 is in the OFF state as shown in FIG.
Vstd)/R flows and charging starts.

On the other hand, the counter 30 receives the A/D conversion start signal ADSTR from the CPU and starts counting the oil conversion lock pulse ADCP sent through the gate 211.

When the count value reaches a certain value, that is, after a certain period of time has elapsed, a signal is sent to the gate 205, and the gate 205 becomes "H".
Switch to state. This state is transmitted to switching element 200 via line 102 and reversed. A second reference voltage Vr is applied to the input terminal on the inverted side of the switching element 200.
Since efo is applied, the first reference voltage Vstd and a lower second reference voltage Vrefo are input to the input side of the ORAnzo 120, and as a result, the charge charged in the integrating capacitor C is Constant current (Vstd-
Vrefo)/R. As a result of discharging, when the terminal voltage 100 of the integrating capacitor becomes lower than the first reference voltage Vstd, the output of the connominator 121 is inverted and the switching element 201 is switched to the "ON" state, and the terminal voltage of the integrating capacitor becomes lower than the first reference voltage Vstd. At the same time, the gate 202 is inverted to the "H" state. gate 2
When 02 becomes 1H'' state, its output is transmitted to the 7-resof 204 via the gate 203, a data input command is given to the terminal of the latch 31, and the count contents of the counter 30 are transferred to the latch 31.

On the other hand, the output of the counter 30 is also input to the gate 209, and the output of the gate 202 is in the "H" state until the output of the gate 209 is inverted to the "H" state due to the output from the counter 3o. When there is no charge, that is, when it takes a long time to discharge the integrating capacitor, the content of the counter is 16.
Proceeds to the base I FOH, at which time the gate 209 is '
The flip-flop 204 applies a data input command to the terminal of the latch 31 via the gate 203, and the count contents of the counter 30 are transferred to the latch 31.

The output of the counter 30 is also input to the gate 212, and when the count content of the counter advances to 7EH in hexadecimal, the gate 212 is in the "H" state. The latch 32 is activated and latches the count contents of the counter. Note that the contents latched at this time are 5 bits b1 to b5 of the counter.

Next, the D converter AD shown in FIG. 7(b) will be explained.

The circuit configuration is basically the same as ADo, but BV is used as an input signal and as a reference signal to judge the brightness of the field.
A connominator 230, switching elements 221, 222, and a flip-flop 220 are added, which compare the input luminance value BV1 of the first area with the reference signal BV and send out a positive/negative sign, and the counter 30 A latch 32 is provided to hold the contents.

Next, the operation of ADl will be explained. Input brightness value Bv
Two input signals, 1 and the reference signal BV, are compared by the converter ξ regulator 230, and when Bvo>Bvl, the converter 230 outputs the "L" state, and the AD converter A
It is input to the flip-flop 220 of D1. On the other hand, the falling edge signal of the AD conversion start signal STR sent from the oil converter ADo, which was explained earlier, is generated when the gate 205 is in the "L" state in ADo. It determines the timing to start charging the integrating capacitor, and when this falling multi-signal is input to the 7-lip float generator 220, the "L" state of the output of the converter Z-lator 230 is transmitted to its output side. Ru. As a result, the switching elements 221 and 222 are set to the illustrated state. This means that in the oil converter explained in Fig. 7 (P), BVo remains as is and Vstd is replaced by
B.V.

can be thought of as replacing VrefoO with Vrefl.

Now, when the oil conversion start command signal ADCH sent from the D converter ADO enters the 'L' state, the switching element 2
23 is set to the state shown. The reference signal Bv is provided to the output receiver 122.

and the value signal BV are input, and the output is the difference (BVo
BVI ) is input to the connominator 123, but one input of the connominator 123 is BVI, and when BY, ) BV, the output of the connomitor 123 becomes "L".

As a result, the switching element 224 is set to the state shown in the figure, so that the current (BVo -
BVl)/R flows and charging starts.

On the other hand, counter 3 common to each oil converter ADo-ADs
0 (as shown in FIG. 7(a)), the counting starts as described above, and when the counted value reaches a predetermined value, the gate 208 goes into the "H" state. The output of 210 is in the "H" state and ADCH is in the "H" state. As a result, the switching element 223 is inverted from the state shown in the figure, and the input side of the operational amplifier 122 has BVI and BVl.
-Vrefl is applied, and the charge of the integrating capacitor C is a constant current (BVl(BVt-Vrefl))
/R=Vrefl/R.

When the terminal voltage 105 of the integrating capacitor becomes lower than the input brightness value BV due to discharge, the output of the converter 123 is inverted and the switching element 224 is switched to the "ON" state, and the voltage between the terminals of the integrating capacitor is is short-circuited, and the gate 225 is inverted to the "H" state. gate 22
The output of 5 passes through gate 226 to flip-flop 227.
, a data input command is issued to the latch 32, and the contents of the counter 30 are latched.

FIG. 8 is a time chart (A) for explaining the operation of the AD conversion unit, and FIG.

First, to explain the operation timing of each part of ADo, C
However, the conversion start signal ADSTR sent from the PU is “H”
In this state, charging of the integrating capacitor starts and the terminal voltage 100 decreases. The counter 30 starts counting and stops counting at the hexadecimal number IFOR. The output signal 101 of the connominator 121 remains in the "H" state during the charging/discharging period of the capacitor, and the output signal 102 (STR) of the gate 205, which switches charging/discharging, remains "L" only during the capacitor charging period. Others are in the "H" state. The latch command signal 103 becomes “H” when the capacitor discharge ends.
The output signal 104 of the gate 209 becomes "H" when the counter reaches the hexadecimal number IFOR.
” condition.

Next, the operation timing of each AD1 to ADs will be explained. When ADSTR is in the @H"H" state, charging of the integrating capacitor is started and the terminal voltage 105 is decreased. The counter 30 has started counting, but the count value is 7 in hexadecimal.
When EH is reached, the gate 212 of AI)o becomes "H" state, the 9 LAT signal goes "H", and the counter contents at that time are held in the latch 32. The charging/discharging switching timing of the integrating capacitor is set at a short time for ADO as well, that is, when the count value of the counter is 3FH in hexadecimal.
The signal ADCH sent from the gate 208 when the
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The chip select signal is the counter 30 for C8o.
The C3I-CSs are sent out after the contents of the counter 30 reach the hexadecimal number IFOH, and the C3I-CSs are sequentially sent out after the contents of the counter 30 reach the hexadecimal number 7EH.

(4) P/S control unit FIG. 9 is a block diagram showing the configuration of the P/S control unit. This control section has the function of converting the A/D converted 8-pit parallel signal into a serial signal and sending it to the CPU.

The control section is a timing signal generating section 91° that operates based on the reference clock signal SCK and the AE data read signal AESTR input from the CPU.
The 7-bit counter 92 starts counting at TR, and the chip select signal C3o =
It is comprised of a decoder 93 that generates C5s, and a P/S register 94 that converts the parallel signal into a serial signal and sends it out.

Next, to explain its operation, the data read signal causes
p The P/S control section starts operating, the 7-bit counter 92 counts the clock pulses, and the decoding section sequentially decodes the clock pulses to generate chip select signals C9o-C86 for selecting the A/D conversion section. occurs, oil conversion part A
Send to DO-ADs. From the D converters, 8-bit luminance values are input to the P/S register 94 from the oil converters ADo-AD8, which are sequentially selected by the chip select signals C3o to C8s.

The p/S register 94 temporarily holds the input 8-bit nosolar signal under the control of the timing signal and clock signal sent from the timing section, converts it into a serial signal, and transfers it to the CPU.

(5) Signal processing within the CPU Next, the signal processing performed within the CPU will be explained based on the flowcharts shown in FIGS. 10 to 14.

First, among the operation switches that turn on in the order of photometry, autofocus, and release, when the photometry switch So is turned on, an interrupt signal is sent to the CPH from the gate 23 shown in FIG. 4, and interrupt processing is started. . In Figure 10, l'-I
Denoted as NTSoJ. Next, after interrupts are disabled, the So routine is entered. First, the state of the automatic focus switch S1 is checked, and if it is ON, the routine jumps to Sl. If it is OFF, check the status of the photometry switch So and turn it OFF.
If it is FF, it is a malfunction of the So switch, so the interrupt is enabled, the process is stopped, and the process waits for the switch So to be turned on again.

On the other hand, if the switch So is ON, the AE subroutine for automatically determining the exposure amount is skipped. The subroutine will be explained later.

After returning from the AE section subroutine, turn on the autofocus switch S.
The state of the switch SO is checked, and if it is OFF, the routine returns to check the switch SO. If the switch S1 is ON, the routine of S1 is entered. The M start signal is sent to the automatic focus detection circuit 14.
Send to.

Thereafter, a series of operations such as focus detection for automatic focus adjustment and motor operation are performed independently of the processing within the CPU. After sending out the AF start signal, the state of S is checked, and if it is OFF, an AF stop signal is sent to the automatic focus detection circuit 14. This allows focus detection and motor operation to be stopped independently of the CPU. When the sending of the M stop signal is finished, it jumps to INTSO. If the switch Sl is ON, the process jumps to the subroutine, and when it returns after completing a series of processes, interrupts are enabled and the state of the switch Sl is checked.

If the switch S1 is OFF, an M stop signal is issued and the process jumps to INTSo, and if the switch S1 is ON, the process jumps to the fart subroutine again. After the above-mentioned interrupt is enabled, when the AF focus signal AFE is sent from the automatic focus detection circuit 14 to the gate 23, the falling edge signal of INT 2 is sent from the gate 23 to the interrupt mechanism. , enters the routine of FIG. 11 INT AFE.

In the INT AFE routine shown in FIG. 11, interrupts are first disabled, an AF stop signal is sent to the automatic focus detection circuit 14, and the focus adjustment mechanism is disabled. After that, the program jumps to the Sosa subroutine and performs a series of processes, and then checks the state of the switch S1. If it is OFF, a routine is entered to check the state of the switch So, but if it is ON, the state of the release switch S2 is checked. If S2 is OFF, the routine returns to check the state of S1 again.

In this way, the camera continues to wait until the release switch S2 is turned ON, but when the AF switch S1 is turned OFF, the camera is unable to operate the release and enters a routine to check the state of the photometry switch So. If the release switch S2 is ON, the user enters the release operation, sets the shutter speed, aperture value, etc., and operates the shutter.

After this, the state of the photometry switch So is checked, and if it is OFF, interrupts are permitted and the process is stopped.

If the switch So is ON, the program jumps to the So routine and starts executing the INTSo routine again.

In the AE subroutine shown in FIG. 12, the MA conversion is executed and the D conversion value is taken into the CPU.

Next, it jumps to the division processing subroutine to be explained later, performs division photometry processing, and returns from the ring routine.
, move on to APEX operation. Here, the shutter speed and aperture value are determined, necessary display data is prepared and sent to the display circuit shown in the third diagram, the bass subroutine is completed, and the process returns to the original routine.

Next, the subroutine of the division process will be explained using FIGS. 13 and 14. In this routine, after determining the exposure value from the brightness values of each area of the subject, the state of the metering mode selector switch SA, which is operated from outside the camera, is checked, and the
Return to routine N.

If photometry mode switch SA is OFF, 4Bmax
- Jump to the min routine and check the brightness BVi of each area of the object.
The maximum value aB of the difference Vi between and the brightness Bvo at the center of the field
Vmax 1 Second largest value ABvA.

The minimum value ΔBVmin and the brightness width vw are determined. This will be explained later.

When the processing in the ΔBmax -min routine is finished, the process returns to the division processing subroutine again, and in order to judge the maximum brightness, BVO+ΔBVmax:) 11.3 BV is determined, and if it is not greater than 11.3BV, ΔBVmax)
2.3 Jump to BV judgment routine. If 11.3BY is larger, use BV to judge the brightness of the center of the field.
Determine o>11.3, and if si is greater than 11.3, Δ
BVmax) Jump to the routine after the judgment in 2.3, and if it is not greater than 11.3, discard the maximum value ABvmax of the brightness difference of the subject obtained in the max-min routine and use the second largest value. ΔBVA is adopted as the new maximum value of the brightness difference.

Next, the routine moves on to the routine after the determination of ΔBVmax) 2.3 BY. Here, the position where the film latitude exists is determined according to the luminance distribution state of the object field, such as the maximum value, minimum value, and middle luminance difference of the luminance difference, and the luminance value BVc necessary for controlling the exposure amount is determined.

The processing procedure is the determination of the maximum brightness difference ABVmax) 2.3, the minimum brightness difference ΔBVmin (-2, 7 determination,
Then, the brightness values BVc to be adopted are classified into three after the judgment of -brightness medium ΔBVw) 5. If we organize this, 1, △BVmax ) 2.3 is satisfied, and (1)
XiangVmin (when -2,7, BVc = BV(1...
・・・・・・・・・(2)(2) ΔBVmin≧
-2,7, (1) reached Vw) When 5, BVc = BV□+ΔBVmin+2.7 -(5)
(11) When ΔBVw≦5, BVc = BVo+△BVmax-2,3・--(6
)2, ΔBVmax≦2.3, (1) ΔBV
min (-2,7 met, (1) ΔBVw > 5
When BVc = BVQ+ΔBVmax-2,3・--(3
) (11) When Vw≦5, BVc = BVo + reached Vmin + 2.7 -・
-(4) (2) When ΔBVmin≧-2,7, BVc = BVo...
...(1). In addition, for example, BVc ” BV
(1...The number shown on the left as (1) is the 13th
This is the same as the classification number shown at the bottom of the flow chart.

FIG. 15 shows an example of the brightness value processing results. To explain this simply, the vertical axis shows the brightness value, and the horizontal axis shows examples. To explain using the leftmost example, this is 18Vmax≦2.3, ΔBVmin≧-2
, 7, it is shown that BV is adopted as BVc.

The classification number in this case is 1. Also, to explain the fourth example from the right, ΔBVmax) 2.3, ΔBVm
If i n≧2,7, and the brightness is medium △BVw) 5, BVo +ABVmin+ 2.7 as BVc.
This indicates that the company will adopt the following. In this case, the classification number is 5
It is.

In addition, the number displayed below the vertical line is BVmax-13v
It shows the size of min, <5 is 5EV small, =
5 indicates 5EV, )5 indicates that it is larger than 5EV.

Finally, a subroutine for calculating ABVmax-min will be explained. In this routine, the field of view is divided into a plurality of regions, and the maximum value ΔBVmax of the difference between the brightness BVi of each region and the brightness BY of the center of the field of view is calculated.

The second largest value BVA and the smallest difference ΔBVmi
nx brightness width ΔBV brightness is reduced, and a flowchart thereof is shown in FIG. Here, an example is shown in which the field is divided into nine parts. Since eight areas other than the central area serving as a reference are to be processed, i = 1 to 9.

First, the initial value of the variable is set at i=1. ΔB
Vmax=ABVi, ΔBVmin=ΔBVi
, ΔBVA=0. Next, to find ΔBVmin, determine the magnitude of ΔBVmin>ABVi, and then calculate ΔBVm
If i n is large, ABVi is stored as ΔBVmin and the process proceeds. Moreover, if it is not large, i is incremented by one and the process proceeds as i=i+1.

Next, ΔBVmax is calculated, but first ΔBVmax)AB
Determine the size of Vi, and if ΔBVmax is large, it is 4V
Store ΔBVmax as A, and store A as ΔBVmax.
Bvi is stored and the routine proceeds to a repeat determination. ΔBV
If ma → ; is large, the second largest difference value ΔBVA is calculated, but first, ABVi :> ABV i is judged to be large or small, and then A
If BVi is large, the process advances to a repeat determination of the routine.

Also, if ABVi is not large, ABVi is
is stored and proceeds to the routine repetition determination.

In the routine repetition judgment, ΔBV while i is smaller than 9.
Returning to the part that calculates min, when the process reaches 9 times, that is, when the luminance of all areas of the divided subject area has been processed, the iterative process is terminated, and the previously calculated ΔBVmax and ΔB
This subroutine is terminated by calculating the difference ΔBVw from Vmin, and the original [Effects of the Invention] As explained above, according to the present invention, in a multi-point photometry device such as multi-segment photometry or spot photometry with multiple memories. In addition, there is no possibility that the part of the subject intended by the photographer is overexposed or underexposed, and the exposure amount is determined rationally and appropriately, taking into account the brightness distribution of other parts of the subject.

4 Brief Description of the Drawings FIG. 1 is a block diagram schematically showing the automatic exposure and automatic focus control portions of a camera incorporating the photometric device of the present invention. FIG. 2 is a diagram showing the arrangement of photoelectric conversion elements. FIG. 3 is a schematic cross-sectional view showing a situation in which the photometric device of the present invention is incorporated into a camera. FIG. 4 is a block diagram showing the main parts of the block diagram shown in FIG. 1 in slightly more detail. FIG. 5 is a block diagram of the photometric circuit.

FIG. 6 is a diagram showing an example of a logarithmic compression circuit. Figure 7 shows A/D
FIG. 3 is a block diagram showing a circuit of a converting section. FIG. 8 is a time chart explaining the operation of the A/D conversion section, and FIG. 9 is a block diagram showing the circuit of the P/S control section. Figures 10 to 1
Figure 4 is a flowchart of signal processing, Figure 10 is photometry,
This shows signal processing in focus detection.

FIG. 11 shows signal processing up to release. FIG. 12 shows the AE subroutine. FIG. 13 shows a subroutine for division processing. FIG. 14 shows a subroutine for determining the maximum value of luminance difference and other values in the division process. FIG. 15 shows an example of the processing result of the brightness value of the object field according to the division processing.

1: Photoelectric conversion element, 13: Photometry circuit for automatic exposure control, 1
0: automatic focus detection element, 14: automatic focus detection circuit, 15
: Processor, So, S, , S2: Operation switch, SA: Photometry mode changeover switch.

Patent applicant: Minolta Camera Co., Ltd., 26 mg figure Figure 10

Claims (4)

[Claims] (1) A photometric circuit that measures multiple parts of the subject and stores photometric signals corresponding to their luminance values, and a signal that corresponds to the luminance portion of the photometric signal that must always correspond to the film latitude width. means for adopting the photometric signal as a reference value, means for determining photometric signals corresponding to the effective maximum brightness portion and the effective minimum brightness portion of the photometric signal as brightness distribution end values, and means for outputting information regarding the film latitude; Based on information regarding the reference value, brightness distribution end value, and film latitude, the exposure amount is determined according to the above reference value, or the brightness portion corresponding to the above reference value falls within the film latitude width within the limit. 1. A multi-point photometry device, comprising means for determining whether to shift the exposure amount in a direction that increases the brightness portion. (2) The photometry circuit is a multi-division photometry circuit that divides the field into a plurality of regions and generates a plurality of luminance signals corresponding to the plurality of regions. Multi-point photometry device described in Section 1. (3) Multi-point photometry according to claim 1 or 2, characterized in that the luminance portion that must correspond within the film latitude width corresponds to the field area that is the target of automatic focus adjustment. Device. (4) As a means of discrimination processing, the brightness of the subject area that must be included within the film latitude is set to a reference value BV_0.
, when the highest brightness in the field is BV_m_a_x and the lowest brightness is BV_m_i_n, the brightness BV_c that determines the exposure amount is calculated using the following formula i, BV_m_a_x-BV_0>E_1, and BV_m
_i_n-BV_0<-E_2 or BV_m_a_x-
BV_0≦E_1, and BV_m_i_n−BV_0≧−
When E_2, BV_c=BV_0 ii, BV_m_a_x-BV_0>E_1, and BV_
m_i_n-BV_0≧-E_2, and BV_m_a_x
- When BV_m_i_n≦E_1+E_2, or BV
_m_a_x−BV_0≦E_1, and BV_m_i_n
-BV_0<-E_2, and BV_m_a_x-BV_m
When _i_n>E_1+E_2, BV_c=BV_m_
a_x-E_1 iii, BV_m_a_x-BV_0>E_1, and BV
_m_i_n-BV_0≧-E_2, and BV_m_a_
When x-BV_m_i_n>E_1+E_2, or B
V_m_a_x−BV_0≦E_1, and BV_m_i_
n-BV_0<-E_2, and BV_m_a_x-BV_
When m_i_n≦E_1+E_2, BV_c=BV_m
_i_n+E_2 The multi-point photometry device according to claim 1, further comprising means for calculating and outputting E_1 and E_2 using constants determined by film latitude.