JPS61173226A - Photometric equipment of camera - Google Patents

Abstract

PURPOSE:To improve the accuracy to detect a reverse light condition by making variable the level of a deciding value to decide a luminance difference between an average luminance and a central part luminance of the field in accordance with an image pickup distance band signal from a distance signal output device. CONSTITUTION:When a distance band signal d1-d4 are emitted in accordance with the distance from a camera to a main object, the farther the distance of the main object is, the more the level of a deciding voltage V4 is lowered, an output voltage V3 of an operation amplifier 21 is decided at a low level, and a reverse light condition detecting signal Sd is emitted. Consequently, even when the rate occupied by a main object 3 in a field 1 is changed, the influence due to this is canceled by the change of the deciding voltage V4, and when the luminance difference between the main object 3 and a background 4 goes to be a prescribed value, the reverse light condition detecting signal Sd can be outputted by the operation amplifier Sd and the detecting accuracy of the reverse condition is improved.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a photometry device for a camera, and more particularly, to a camera capable of recognizing a backlight condition by detecting the brightness difference between the average brightness and partial brightness of a subject. The present invention relates to a photometric device.

(Prior art) Regardless of the brightness of the subject, when the difference between the average brightness of the subject and the partial brightness reaches a certain value, it is assumed that the scene is backlit, and the mode is switched from the steady light photography mode to the flash photography mode. The photometric device of the camera is well known (Special Publication Act 1987
-29408).

However, in this conventional photometry device, the photoreceptor for partial photometry that measures a part of the center of the subject actually has a photometry area of a certain size, and that area can literally be used as a spot. It is difficult to make it as small as a single object due to the optical system or the gain of photoelectric conversion (even if this were possible, it would be difficult to has the problem that the correction for backlight does not work at all). As a result, for example, the fourth
As shown in FIG.
As shown in Figure (B'), the main subject 6 and the background 4 are
Does the output of the backlight detection circuit change even if the difference in brightness is the same?
This will result in As is clear from FIGS. 4(A) and 4(B), in principle, if the main subject 6 is large, the partial photometry area 2 will be affected by the brightness of the main subject 60m. When the main subject 6 is small, a part of the background 4 enters the partial photometry area 2, and the brightness of the background 4 affects the Z. In this way, even though the brightness difference between the main subject 3 and the background 4 is the same between the state shown in Fig. 4(a) and the state shown in Fig. 4(f3), the shooting distance is different. , there is a difference in the size of the main subject, and for this reason, the situation shown in Figure 9 (A) may be recognized as backlighting, but the situation shown in Figure 4 (B) may not be recognized as backlighting. There was a problem.

(Objective) In view of the above-mentioned problems, an object of the present invention is to provide a camera capable of comparing the average brightness of a subject and the brightness of a central part, and detecting a backlight condition based on the comparison result. An object of the present invention is to provide a photometric device that improves the accuracy of state detection using simple electronic means.

(Summary) The camera photometry device of the present invention determines the level of the determination value for determining the brightness difference between the average brightness of the object field and the central brightness.
This is made to vary according to the photographing distance band signal from the distance signal output device.

(Example) Hereinafter, the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is an electrical circuit diagram of a photometric device for a camera showing an embodiment of the present invention. In FIG. 1, the anode of the partial photometry photodetector 11, which is made of a silicon photodiode or the like and is used to photometer only the central area of the field, is an operational amplifier connected to the terminal 10 to which the reference voltage VREF is applied. 12, and the cathode of the partial photometry photodetector 11 is connected to the inverting input terminal of the operating switch 1120 and the cathode of the logarithmic compression diode 16.
The anode of the diode 13 is the output of the operational amplifier 12.
A partial photometry circuit is configured by connecting to the end.

A light receiving element 14 for average photometry consisting of a silicon photodiode for photometering the entire area of the object field. operational amplifier 1
5 and the logarithmic compression diode 16 are also connected in the same manner as above to constitute an average photometry circuit. At the next stage, a differential amplifier circuit is constructed, which includes four resistors 17 to 20 having the same resistance value and an operational amplifier 21. That is, the output terminal of the average photometry operational amplifier 15 is connected to the non-inverting input terminal of the operational amplifier 21 via the resistor 18, and
Terminal 1Q to which reference voltage V is applied via resistor 17
It is connected to the. The inverting input terminal of the operational amplifier 21 is connected via a resistor 19 to the output terminal of the partial photometry operational amplifier 12, and is connected via a resistor 20 to the output terminal of the differential amplification operational amplifier 21 itself. The output terminal of the operational amplifier 21 is the output terminal of the operational amplifier 21, that is, the operational amplifier 1220 inverts which forms a comparator for detecting whether or not there is a backlight condition from the magnitude of the output difference between the partial photometric output and the average photometric output. Connected to the input end. A reference voltage V is connected to the non-inverting input terminal of the operational amplifier 22 via a resistor 26.
A terminal 10 to which RF and F are applied is connected.

Further, a judgment value level variable circuit 60 is connected to the non-inverting input terminal of the operational amplifier 22. In this judgment value level variable circuit 60, a well-known current mirror circuit is formed by two transistors 61, 32.33, 34.36, 37.39, 40.42 and 43, respectively.
The emitters of the PNP transistors 1 and 62 are directly connected to the terminal 50 to which the power supply voltage Vcc is applied, and the collectors of the NPN transistors 33, 36, and 42 are connected to constant currents Iji and Ij, respectively.
2. Ij3. Ij4 (Iji:) Ij2) I
Constant current source 45.46.4 for flowing jg)Iji)
7.48 to the terminal 50. The collector of the transistor 31 is connected to the non-inverting input terminal of the comparison/judgment operational amplifier 22, and the transistor 6
2 collectors are the above NPN) transistors 34 and 37.
.

4() and 43 collectors. The bases of the transistors 63 and 64 are NPN) to the collector of the transistor 35, the bases of the transistors 66 and 670 are NPN) to the collector of the transistor 38;
The bases of transistors 9 and 40 are connected to the collector of an NPN transistor 41, and the bases of transistors 42 and 43 are connected to each other.This camera is equipped with a distance measuring circuit 51, and the distance measuring circuit 51 is connected to the collector of an NPN transistor 41. It is connected to a photoelectric conversion element 56 such as a silicon photodiode array arranged on the surface. The infrared light of the infrared light emitting diode 55 emitted from the lens 54 of the light emitting window is reflected by the subject and received by the photoelectric conversion element 53, so that the distance measuring circuit 51 generates a distance band signal according to the distance to the subject. is now emitted. That is, as a result of distance measurement, for example, when the distance to the subject is 0.8 m to 1.2 m, the distance band signal dI is emitted, and when the subject distance is 1.2 m to 2 m, the distance band signal d2 is emitted. , Similarly, when the distance is 2 m to 6 m, the distance band signal d6 is emitted, and when the distance is 31r1-CX), the distance band signal d4 is emitted. These distance band signals d1 to d4 are high level (hereinafter referred to as "toll level") signals.

The distance band signals d1 to d of the distance measuring circuit 51 are
Each output terminal that emits 4 is connected to an inverter 56 to 59, respectively.
It is connected to the bases of the transistors 35, 38, 41 and 44 of the judgment value level variable circuit 60 through.

The camera photometry device configured as described above operates as follows. When you point the camera at the subject you want to photograph, the light of the main subject at the center of the field is received by the condenser lens 8, mainly on the light-receiving element 11 for partial photometry, and the background is mainly received by the light-receiving element 14 for average photometry by the condenser lens 9.
The light is received by the If the photocurrent flowing through the light receiving elements 11 and 14 is Ip+ + l:p2, then the operational amplifier 1
2.15 output voltage v1. v2 is the reference voltage VR
For F and F, (1 is Boltzmann's constant + T I absolute temperature, q: electron charge), and Is is the logarithmic compression diode 13° 16
is the reverse saturation current. For this reason, the output voltage v3 of the operational amplifier 21 for differential amplification is determined by the above equations (1) and (2). A signal d is emitted. Then, the output of the inverter 56 becomes low level (
The outputs of the other inverters 57 to 59 become "H" level (hereinafter referred to as "L level"), so the transistor 35 of the judgment value level variable circuit 30 is turned off and the transistors 38, 41.44 are turned on. . Therefore, at this time, transistors 63 and 34 are turned on, but transistors 66, 37, 69, 40, 42 and 46 are turned off,
A constant current Ij1 flows only through the constant current source 45. Constant current Ij
When + flows to the collector of the transistor 66, the current Ij1 also flows to the collector of the transistor 34 and the collector of the transistor 32 due to the current mirror effect, so that the current Ij+ similarly flows to the collector of the transistor 61. Therefore, if the resistance value of the resistor 26 is R2, then the judgment voltage ■4 at the non-inverting input terminal of the comparison judgment operational amplifier 22 is as follows with respect to the reference voltage ■REFK: v4−■j1・R12... (4) becomes.

Therefore, the output voltage of the differential amplification operational amplifier 21 ■6
When the determination voltage (4) becomes equal, the level power at the output terminal of the operational amplifier 22 is inverted from 'H' to l L l, and the operational amplifier 22 generates a backlight state detection signal Sd.

For example, the brightness difference between the main subject and the background is Ip2.
/Ip+ = 3, the voltage V3 in the above equation (6)
is V3 = VT 4n3 ζ28 rr + V (at room temperature), so the voltage V4 in equation (4) above is also V
4 = Ijl ・R2 = 28 mV, when the central brightness value decreases by about 1.6 EV with respect to the average brightness value, the operational amplifier 22 outputs the backlight state detection signal Sd of L level. Ru.

Assuming that the distance to the main subject becomes 1.5 m, the distance measurement circuit 51 emits a distance band signal d2. In this case, since the transistor 38 is turned off, the transistors 36 and 37 are turned on, and the constant current source 46 causes a constant current Ij2 to flow to the collector of the transistor 66. Therefore, a current Ij2 flows to the collector of the transistor 37 and the collector of the transistor 32. , furthermore, the current ■J2 flows through the collector of the transistor 61 as well. Therefore, at this time, the operational amplifier 220 judgment voltage v4
becomes V4=Ij2・R2 (5).

When the distance to the main subject becomes slightly further than the above-mentioned distance, the distance band signal d6 is emitted from the distance measuring circuit 51,
Furthermore, when the main subject is further away than this, a distance band signal d4 is generated. When the distance band signal d3 is generated, the transistor 41 is turned off, so at this time the transistors 39 and 40 are turned on, and a constant current Ijg flows through the constant current source 47, so that a current ■j flows into the collector of the transistor 61.
3 flows. When the band signal d4 is issued, the transistor 44 is turned off, the transistors 42 and 43 are turned on, and a constant current J4 flows through the constant current source 48, so that a current Ij4 flows through the collector of the transistor 31. .

Therefore, when the distance band signal d3 is emitted, the operational amplifier 220 judgment voltage v4 is as follows: V4=■J3・R2...(6) When the distance band signal d4 is emitted, V4=
Ij4・R2...(7) It becomes.

In this way, when the distance band signals d1 to d4 are emitted according to the distance from the camera to the main subject, the above-mentioned judgment voltage v4 is set to the reference voltage
With respect to R, the voltages shown in (4) to (3) above are obtained.

The above constant currents Ij1 to Ij'4 are 1>Ij2>I
Since j3>Ij4, the above judgment voltage v4 is Ijl・
R2〉Ij2・R2＞Ij5・R2〉■j4・R2, and as the distance from the main subject increases, the level of judgment voltage ■4 decreases, and the output voltage ■3 of the operational amplifier 21 is determined at a low level and backlighting is performed. A state detection signal Sd is generated.

In other words, as mentioned above, when photographing a person outdoors in bright light, for example, if the main subject 3 is at a close distance, as shown in Figure 4 (A), there will be a portion within the area of the main subject 3. Since the photometry area 2 is completely entered and then shifted, at this time the difference between the partial photometry output and the average photometry output, that is, the output voltage 3 of the differential amplification operational amplifier 21 is high, and therefore the backlight state detection signal Sd is The judgment voltage v4 of the comparative judgment operational amplifier 22 for generating the image is also set to a high voltage as shown in the above equation (4), but as shown in Fig. 4 (B), the distance of the main subject B becomes longer and the background becomes darker. If a part of the photometer falls within the partial photometry region 2, the output voltage (3) of the operational amplifier 21 decreases, so at this time the operational amplifier 220
The level of judgment voltage (4) is also reduced. As the distance increases, the level of the determination voltage (4) is also lowered as shown in FIG. 5 in accordance with the distance band. That is, as shown in FIG. 5, the distance band signals d1.
d2. d3. When c14 is issued respectively, the ``-distributed constant voltage V4 for each of these signals is respectively IJl.
-R2-28mV (-1,6Ev).

■J2・R2-22,5mV (-1,25E■), Engineering J
3.R2-18mV (1, D EV ), I J 4
□R2-13,5rnV (0,75EV) levels.

Therefore, even if the ratio occupied by the main subject B in the scene 1 changes, the effect of this is offset by the change in the judgment voltage 4, and the luminance difference between the main subject 6 and the background 4 becomes a predetermined value. At times, the operational amplifier 22 can output a backlight state detection signal Sd, improving the accuracy of detecting a backlight state. Note that the determination voltage (4) for generating the backlight state detection signal Sd is not limited to the level shown in FIG. 5, but can be set to any level by appropriately setting the constant currents Ij1 to Ij4. can do.

FIG. 2 is an electrical circuit diagram of a photometric device for a camera showing another embodiment of the present invention. In the photometric device of this example,
A resistor 61 and a backlighting state display element 62 consisting of a light emitting diode are connected in series between the output terminal of the operational amplifier 22 forming a comparison/judgment device for detecting the backlighting state and the voltage applying terminal 50 of the power source. It is connected. Further, the camera having this photometry device is equipped with an automatic focus adjustment device 65 of an appropriate size. The photographing lens 66 stands so that it can be moved for focus adjustment by a motor (not shown).
A movable contact piece 68 that can slide on the conductor 67 connected to the power supply voltage application terminal 50 in conjunction with the movement of the photographing lens 66
can come into contact with any of the four fixed contact pieces 69, 70, 71, and 72. These four fixed contact pieces 69
-72 are respectively connected to one input terminal of four Nant gates 76-76. The other input terminals of these four Nant gates 76 to 76 are respectively connected to the output terminals of the distance measuring circuit 51 which generate distance band signals d1 to d4. The output terminals of these Nante gates 73 to 7B are connected to the respective input terminals of a four-man powered NAND gate 77, and the output terminal of this Nante gate 77 is connected to one end of a magnet 78 for stopping the movement of the photographic lens 66. ing.

The other end of this magnet 7B is grounded. The rest of the circuit configuration is exactly the same as the electric circuit of the photometric device shown in FIG. 1, so the same parts are given the same reference numerals and the explanation thereof will be omitted.

Next, the operation of the photometric device shown in FIG. 2 will be explained, mainly focusing on the differences from the photometric device shown in FIG. 1. When the photographing lens 66 is retracted backward by the lens drive motor, that is, when it moves from focusing on a short distance to gradually focusing on a long distance, it is linked to the movement of the lens 66. The movable contact piece 68 is connected to the fixed contact piece 69,
70, 71, and 72 in this order. When the movable contact piece 68 contacts the fixed contact piece 69, the power supply voltage Vcc, that is, the IT' level, is applied to one input terminal of the Nant gate 7B, and when the movable contact piece 68 contacts the fixed contact piece 70, one of the Nant gates 74 When the 'H° level is applied to the input end and similarly contacts the fixed contact pieces 71 and 72, 'I' is applied to one input end of the NAND game) 75 and 76, respectively.
-1' level is now applied. The state in which the movable contact piece 68 is in contact with the fixed contact pieces 69 to 72 is determined by distance band signals d1 to d1 generated by the distance measuring circuit 51 according to the photographing distance.
This corresponds to a state in which the photographing lens 66 is located in four distance bands d4. Therefore, the distance measuring circuit 51' I-T
' When any of the distance band signals d1 to d4 of the level is applied to the other input end of one of the corresponding Nant gates 76 to 76, the photographing lens 66
moves, and when the "H" level is applied to one input terminal of the Nandts gate to which the distance band signal is applied, the output of the same Nandts gate becomes "L" level, and therefore, the Nandts gate 77 The output becomes ゛H level and the magnet 78
is excited and the movement of the photographing lens 66 is stopped.

For example, if the distance to the main subject is in the distance band of 3m-(1), the distance measurement circuit 51 outputs the distance band signal d.
4 is emitted, while the photographic lens 66 is in the out-of-focus position, the outputs of the four Nantes gates 7 and 6 are all at the 'H' level, and therefore the output of the Nantes gate 77 is 'L'. The magnet 78 is kept in a de-energized state, but when the photographic lens = 16-66 reaches the focusing position in the above distance range, the movable contact piece 68
comes into contact with the fixed contact piece 72, and at this time both of the forces of the Nantes gate 76 become the 'H level', so the output of the Nantes gate 76 goes to the 'L' level, and therefore the output of the Nantes gate 77 becomes the °H level. , the movement of the photographing lens 66 is stopped by the magnet 78.

When the distance band signal d4 is emitted, as described above, due to the operation of the variable judgment value level circuit 30, the constant current ■j4 that impedes the constant current source 48 is transferred to the non-inverting input terminal of the comparison judgment operational amplifier 22. The distance band signal d is supplied to the non-inverting input terminal of the operational amplifier 22.
The determination voltage (4)-IJ4·R2 corresponding to 4 is applied. When the output voltage V3 of the differential amplification operational amplifier 21 reaches the determination voltage (4), the operational amplifier 22 generates an L" level backlight state detection signal Sd. When the backlight state detection signal Sd is emitted, The backlighting state display element 62 lights up, and the light emitting display warns the photographer of the backlighting state.When the distance band signals d1 to d3 are emitted from the distance measuring circuit 51, the operation is similar to that described above. While automatic focus adjustment is performed, the level of the judgment voltage v4 of the operational amplifier 22 is determined according to the distance band signals d1 to d3.When a backlight condition is detected, the backlight condition detection signal 62 is lit. A warning will be given to the photographer.

FIG. 6 is an electrical circuit diagram of a photometric device for a camera showing still another embodiment of the present invention. The photometric device of this embodiment is provided with an automatic backlight correction circuit 80 in place of the backlight status display circuit of the photometric device shown in FIG. 2, and the other circuit configurations are as shown in FIG. Since it is similar to a photometric device, the configuration and operation of this automatic backlight correction circuit 80 will be described below. an automatic backlight correction circuit 8 operated by a backlight state detection signal Sd emitted from the operational amplifier 22;
0 is constructed as follows.

2 PNP) transistors 82 and 86 and 3 N
PN transistors 84, 85, and 86 form a current mirror circuit, which is well known in the art.

The emitters of the transistors 82 and 83 are connected to the power supply voltage application terminal 50, the collector of the transistor 84 is connected to the power supply voltage application terminal 5° via the constant current source 81, and the collector of the transistor 85 is connected to the power supply voltage application terminal 50. is connected to the collector of the transistor 8.
3 is connected to the reference voltage application terminal 10 via a resistor 87.
The collector of the transistor 86 is connected to the inverting input terminal of an operational amplifier 88. The emitters of transistors 84-8B are grounded. The non-inverting input terminal of the operational amplifier 88 is connected to the output terminal of the average photometry operational amplifier 15. A variable resistor 89 for setting film sensitivity is connected between the inverting input terminal and the output terminal of this operational amplifier 88, and the output terminal of the operational amplifier 88 is connected to the base of an NPN transistor 91 for expansion. He is talented. The emitter of this transistor 91 is connected to the inverting input terminal and output terminal of an operational amplifier 90 forming a buffer amplifier. This operational amplifier 9o has the first and second
The two non-inverting input terminals (1) and (2) are connected to the reference voltage application terminal (10), and the first non-inverting input terminal (0) is connected to the reference voltage application terminal (10).
The second non-inverting input terminal (2) is connected to the collector of the transistor (83). The selection signal input terminal for selectively activating the two non-inverting input terminals ■ and ■ of this operational amplifier 90 is connected to the output terminal of the comparison judgment operational amplifier 22 that generates the backlight state detection signal Sd. There is.

The collector of the transistor 91 is connected to the inverting input terminal of an operational amplifier 92 for exposure determination, and the power supply voltage is connected to the collector through a parallel circuit of an integrating capacitor 93 and a trigger switch 94 that opens in synchronization with the start of running of the front shutter curtain. It is connected to the application terminal 50. The non-inverting input terminal of the operational amplifier 92 is at the reference voltage ■R□. The output terminal of the operational amplifier 92 is connected to the power supply voltage application terminal 50 via a shutter control magnet 96.

In the automatic backlight correction circuit 80 configured as described above, since a constant current IjO flows through the collector of the transistor 84 by the constant current source 81, the transistor 85
, 86 and the collectors of transistors 82 and 83, and therefore, current Ijo also flows through resistors 87 and 89, respectively. Assuming that the resistance value of the resistor 87 is R3, a voltage (■REF + Ijo·R3) is applied to the second non-inverting input terminal (■) of the operational amplifier 90.

Also, the resistance value of the variable resistor 89 for setting the film sensitivity +I
jO·R□sO) is applied.

Here, if the comparison judgment operational amplifier 22 does not detect the backlight condition and its output level is °H',
Since the operational amplifier 90 selects the first non-inverting input terminal ■ to be in the movable state, the output terminal of the operational amplifier 90, that is,
The voltage at the emitter of transistor 91 is equal to the reference voltage RO. Therefore, the base-emitter voltage ■BE of the transistor 91 is as follows.

Next, when the operational amplifier 22 for comparison and determination outputs the backlight state detection signal Sd of the I L + level, the second non-inverting input terminal (2) of the operational amplifier 90 is selected to be in the movable state, so at this time, the transistor 91 ``Voltage (vR]: F + 1.io.R3) is applied to the emitter of . Therefore, the base-emitter discharge voltage BE of the transistor 910 is as follows. That is, if the base-emitter voltage .beta.BE of the transistor 91 is detected by the operational amplifier 22, the voltage (IjO.R3) will change. Here, for example, Ijo −R3=VT−e, 2”=18 mV
If the constant current ■JO and the resistance value R3 are set so that When the collector current of is Ic, the operational amplifier 22 outputs the backlight state detection signal Sd, and the voltage ■BE changes to the voltage ■3' of the equation (9). Tonaru when it changes to.

Therefore, when the backlight state detection signal Sd is not generated from the operational amplifier 22, when the shirt shutter release is performed and the trigger switch 94 changes from the on state to the off state, the integrating capacitor 93 changes as described above! - It is charged by the collector current Ic of the transistor 91. Then, when the voltage at the inverting input terminal of the operational amplifier 1920 gradually decreases and reaches the reference voltage VREFC, the output of the operational amplifier 92 is inverted to the 'L level' or 'IT' level, and the excitation of the shutter control magnet 96 is released. The trailing curtain is run and normal exposure control without backlight correction is performed.

When the backlight state detection signal Sd is generated from the operational amplifier 22, when the trigger switch 94 is turned off by the shutter release, the integrating capacitor 93 is charged by the collector current Ic'-"!c of the transistor 91, as described above. Therefore, the exposure time until the shutter control magnet 96 is de-energized by the output of the operational amplifier 92 and the rear curtain starts running takes twice as long as the normal case, and as a result, the exposure time is 1Ev. exposure compensation will be added.

Note that the distance measuring devices of the above embodiments are all equipped with a distance measuring circuit 51 that automatically measures the distance based on the subject's weight. Even if you do not have a distance ring, for example, when you turn the distance ring to set the shooting distance, the distance ring will generate a signal corresponding to the set distance band, and the distance ring or other distance signal output device will generate a signal that corresponds to the set distance band. The generated signal is converted into a judgment value level variable circuit 60.
It may also be possible to lead to

(Effects of the Invention) As described above, according to the present invention, when detecting a backlight condition by determining the brightness difference between the average brightness of the object field and the brightness of the central part, the determination value is determined according to the shooting distance band. Since the level of ℃ is varied, even if the proportion of the main subject in the scene changes, it is possible to uniformly determine that the subject is backlit for the same brightness difference. The detection accuracy of backlight conditions can be significantly improved, and the present invention has effects such as being able to be constructed using a simple and very simple electric circuit.

[Brief explanation of the drawing]

FIG. 1 is an electrical circuit diagram of a photometric device 6' showing one embodiment of the present invention. FIG. 2 is an electrical circuit diagram of a photometric device 6' showing another embodiment of the present invention. 4A and 4B are explanatory diagrams showing respective states when the ratio of the main subject in the field is large and small, FIG. 5 is an explanatory diagram showing an example of the relationship between a distance band signal and a determination voltage for detecting a backlight condition. 1...Subject 2...Partial metering area 6...Main subject 4...Background 11...Partial Light-receiving element 12 for photometry...Operational amplifier 14 for partial photometry...
・Light-receiving element 15 for average photometry... Operational amplifier 22 for average photometry...
・Comparison/determination operational amplifier 30 for detecting backlight conditions...Judgement value level variable circuit 51...
・Distance measurement circuit (distance signal output device) d1 to d4...Distance band signal

Claims (1)

[Scope of Claims] A photometry device for a camera that compares the average brightness of a subject and the brightness of a central part, and when the difference in brightness reaches a determination value, it is possible to recognize that the camera is in a backlit state. A distance signal output device that generates a distance band signal according to the shooting distance to the main subject, and a level of the above judgment value when this signal is a short distance band signal based on the distance band signal from this distance signal output device. A photometry device for a camera, comprising: a judgment value level variable circuit that changes the level of the judgment value from the large side to the small side when the signal is a long distance band signal.