JP2001091988A - Flash light controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve exposure accuracy at the time of flash light emission photographing by securing the photometric accuracy of preliminary light emission and consequently accurately calculating a main emitted light quantity even in the case that a reflected light quantity at the time of the preliminary light emission is too small or too large. SOLUTION: This controller is provided with a flash light emitting part 27 executing main light emission at a photographing time and the preliminary light emission before photographing, a flash photometric part 26 executing the photometry of reflected light from an object caused by the preliminary light emission by dividing a field and a flash controlling part 29 to control so that the gain of the photometric area of the flash photometric part whose output becomes out of a specified range is reset (S112) and the preliminary light emission (S113 and S114) by the flash light emitting part 27 and preliminary light emission photometry (S115) by the flash photometric part 26 are executed again in the case that at least either one of the outputs from the flash photometric part 26 is out of the specified range (S110).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flash control device for optimally controlling the amount of flash light emission.

[0002]

2. Description of the Related Art Conventionally, a TTL light control method has been mainly used for a flash control device of this type in the case of a control method of a flash light emitter (strobe) of a single-lens reflex camera. In some cases, preliminary light emission is performed before main light emission at the time of shooting, and light reflected from a subject is measured to obtain information for main light emission.

For example, JP-A-3-68928 discloses that
An automatic dimming control device is disclosed in which reflected light from a subject at the time of preliminary light emission is divided and photometrically measured, a reflectance distribution of the subject is obtained based on the result, and information for main light emission is obtained. Further, there has been a device in which the amount of light required for main light emission is determined based on the photometry result of the preliminary light emission, and the flash light emitting unit performs main light emission with the required amount of light emission as a target.

[0004]

However, in the above-mentioned conventional flash control device, the reflected light of the preliminary light emission is too small,
Because the size was too large, the photometry range of the flash photometry unit may be exceeded, and the photometric value may not be sufficiently reliable. In particular, in a method in which the light emission amount of the main light emission at the time of shooting is determined in advance based on the light measurement output at the time of the preliminary light emission, the light measurement accuracy at the time of the preliminary light emission directly affects the light emission accuracy of the main light emission. In some cases, sufficient exposure accuracy could not be obtained.

An object of the present invention is to ensure the photometric accuracy of the preliminary light emission even if the amount of reflected light during the preliminary light emission is too small or too large, and as a result, to accurately calculate the main light emission amount Accordingly, it is an object of the present invention to provide a flash control device capable of improving exposure accuracy at the time of flash emission photographing.

[0006]

In order to solve the above-mentioned problems, a first aspect of the present invention is to provide a flash light emitting section (27) for performing main light emission at the time of photographing and preliminary light emission before photographing, and an object by the preliminary light emission. A flash photometric unit (26) for measuring the reflected light from the object by dividing the field of view, and when at least one of the outputs from the flash photometric unit is out of a predetermined range (S110), the output is set to a predetermined value. The gain of the light metering area of the flash light meter that is out of the range is reset (S111), and the preliminary light emission by the flash light emitter (S113, S114) and the preliminary light meter by the flash light meter (S115) are performed again. And a flash control unit (29) for controlling the flash control.

In a second aspect of the present invention, a flash light emitting section (27) for performing main light emission at the time of photographing and preliminary light emission before photographing, and measuring light reflected from a subject by the preliminary light emission by dividing an object field. And at least one of the outputs from the flash photometer (26) and the output from the flash photometer is out of the predetermined range (S21).
0), a flash control unit (29) that controls the output of the photometric area of the flash photometric unit whose output is outside a predetermined range to a predetermined value (S211). It is a control device.

According to a third aspect of the present invention, there is provided a flash light emitting section (27) for performing a main light emission at the time of photographing and a preliminary light emission before photographing, and a photometry by dividing an object field by a reflected light from a subject by the preliminary light emission. A flash light meter (26), a main light emission amount calculator (30) for performing an operation for controlling main light emission based on the output of the flash light meter, and at least one of the outputs from the flash light meter. When the output is outside the predetermined range (S310), the photometry area of the flash photometry unit whose output is outside the predetermined range is not used for the calculation by the main light emission amount calculation unit (S31).
1) a flash control unit (29) that performs control as described above.

According to a fourth aspect of the present invention, there is provided a flash light emitting section (27) for performing a main light emission at the time of photographing and a preliminary light emission before photographing, and a photometry by dividing an object field by a reflected light from a subject by the preliminary light emission. The effective area determining unit (S411) for determining the light measuring area to be used for the main light emission control based on the output of the flash light measuring unit. When the output of the photometry area of the flash photometry unit is out of the predetermined range (S412), control is performed such that preliminary emission by the flash emission unit (S414) and preliminary photometry by the flash photometry unit (S415) are performed again. A flash control unit (29).

A fifth aspect of the present invention provides a constant light metering section (21) for dividing the luminance of the object scene by the constant light to measure the light, and a flash light emitting section (main light emission during photographing and preliminary light emission before photographing). 2
7) a flash light meter (26) for measuring the reflected light from the subject due to the preliminary light emission by dividing the object field, and based on the luminance of the stationary light measured by the stationary light meter. A flash control unit (29) for resetting the gain of the photometry area of the flash photometry unit and performing preliminary flash photometry.

According to a sixth aspect of the present invention, in the flash control device according to the fifth aspect, the flash control unit corresponds to an area where the brightness of the steady light measured by the steady light meter is large. The flash control device is characterized in that the gain of the photometry area is reduced and control is performed so as to perform pre-flash photometry.

[0012]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
An embodiment of the present invention will be described in more detail. (First Embodiment) FIG. 1 is a view showing an optical system of a first embodiment of a flash control device for a camera according to the present invention. The light beam that has passed through the taking lens 1
To form an image on the diffusion screen 3 once. Thereafter, the light reaches the photographer's eye through the condenser lens 4, the pentaprism 5, and the eyepiece 6.
On the other hand, a part of the light beam diffused by the diffusion screen 3 is re-imaged on the stationary light metering element 9 through the condenser lens 4, the pentaprism 5, the light metering prism 7, and the light metering lens 8.

As the stationary light metering element 9, for example, a light receiving element such as an SPD (silicon photodiode) is used, and as shown in FIG. 3, the field is divided into five areas B1 to B5. Photometry and output the respective photometric values.

At the time of photographing, first, the aperture 10 is stopped down to a predetermined value, and at the same time, the quick return mirror 2 is flipped up. Thereafter, at the time of preliminary light emission by the flash light emitter 15, a part of the light flux substantially formed and reflected on the shutter 11 is re-imaged on the light control element 13 through the light control lens 12. At the time of main light emission by the flash light emitter 15, the shutter 11 is opened and, for example, a CCD (charge coupled
The light flux is imaged on the light receiving surface of the image sensor 14 constituted by a device or the like.

The dimming element 13 is composed of an SPD, a capacitor for accumulating a photocurrent from the SPD, an amplifier, and the like. As shown in FIG. The regions S1 to S5 respectively correspond to B1 to B5 in FIG.

The quick return mirror 2 is a half mirror that transmits a part of the light. A part of the transmitted light is bent downward by the sub-mirror 16 and guided to the focus detecting unit 17. The focus detection unit 17 detects the focus state of any one of the central regions F1 to F5 of the object field shown in FIG. 3, and the photographic lens 1 is driven until the focus state is achieved.

FIG. 2 is a block diagram showing a flash control device according to the first embodiment. As shown in FIG. 3, the stationary light metering unit 21 is a unit that divides the object field into five and measures the constant light. The flash light emitting unit 27 is a part that performs main light emission during photographing and preliminary light emission before photographing.
Is equivalent to The sensitivity setting unit 28 is a part for setting sensitivity information of the image sensor 14.

The exposure calculator 22 calculates the output from the stationary light metering unit 21 and the open F value, focal length, and exit pupil position of the photographing lens stored in the lens microcomputer 31 which is a microprocessor provided in the photographing lens. Lens information such as
This is a section for calculating an appropriate exposure value for the steady light exposure based on the sensitivity information of the image sensor 14 from the sensitivity setting section 28. The calculation result is decomposed into an aperture value and a shutter value, and the sequence control section 24 and the like. Output to

When a release signal is input from the release switch 23, the sequence control unit 24 flips up the quick return mirror 2, narrows the aperture 10, and issues a preliminary light emission instruction to the light emission control unit 25. 11 and, at the same time,
This is a part for controlling a series of operations such as issuing an instruction for main light emission.

A light emission control unit 25 controls a flash light measurement unit 26, a flash light emission unit 27, and the like based on signals from the exposure calculation unit 22, the sequence control unit 24, the flash control unit 29, the sensitivity setting unit 28, and the like. It is.

The flash control section 29 is a section for inputting the preliminary light emission integrated value from the flash photometry section 26 and determining whether or not the output from the flash photometry section 26 is out of a predetermined range. The gain setting unit 32 resets the gain of the photometry area of the flash light measurement unit 26,
7 and preflash measurement by the flash photometer 26 are performed again.

The main light emission amount calculation unit 30 calculates a preliminary light emission integration value from the flash light measurement unit 26, a light measurement value from the stationary light measurement unit 21,
The photographing distance value from the lens microcomputer 31 and the flash light emitting unit 27
The main light emission amount is calculated on the basis of the preliminary light emission guide number, the aperture value from the exposure calculation unit 22, the sensitivity value from the sensitivity setting unit 28, and the like, and the value is output to the light emission control unit 27.

The gain setting section 32 is a section for calculating the amplifier gain of the flash photometer 26 and setting the gain of the flash photometer 26.

Here, the operations of the exposure calculation unit 22, the main light emission amount calculation unit 30, the flash control unit 29, the light emission control unit 25, the gain setting unit 32, and the sequence control unit 24 are performed by a one-chip microprocessor 40 (hereinafter referred to as a microcomputer). (Abbreviated) is realized by the internal calculation.

The interchangeable lens 34 includes a lens driving unit 35 driven and controlled based on signals from the focus detecting unit 17 and the lens microcomputer 31, a lens optical system 36 driven by the lens driving unit 35, and a lens optical system 36. And a lens microcomputer 31 that stores lens information such as the open F-number, focal length, and exit pupil position of the lens optical system 36 and controls the inside of the lens.
And the like.

The flash photometric section 26 is a section for measuring the reflected light from the subject by the preliminary light emission while dividing the object scene, and includes the above-mentioned storage type photometric element 13.
The flash photometer 26 multiplies the photocurrent generated by the SPD by a different amplifier gain for each area, and accumulates the amplified current in the integrating capacitor. At the time of reading, the electric charge stored in the capacitor corresponding to each area is read as a voltage value. Therefore, if the gain is set to an appropriate value according to the amount of incident light, the accumulated value can be prevented from being saturated or too small, and the dynamic range of the flash photometer 26 can be increased.

The above-described stationary light metering section 21 measures the steady light luminance of an area divided into five sections, which is substantially the same as the division shape of the flash metering section 26. In the area where the steady light luminance is large, it is expected that a large amount of light will be incident on the flash photometric unit 26 even in the preliminary flash photometry performed thereafter.

Preliminary photometry is performed in two steps. First, flash light is emitted, the reflected light from the subject of the preliminary light emission is measured, and the preliminary light emission is accumulated. The light entering the flash light measuring unit 26 also includes a steady light component. Thereafter, without performing flash light emission, photometry is performed by the same flash photometer 26 with the same gain, the same accumulation time, and
It also accumulates steady light. The value obtained by subtracting the accumulated value of the steady light from the accumulated value of the preliminary light emission is the net preliminary light emission accumulated value. Therefore, if the luminance of the steady light is high, the accumulated value of the preliminary light emission is saturated, and the preliminary light emission cannot be measured correctly.
Therefore, by setting the amplifier gain of the flash photometric unit 26 corresponding to an area where the steady light luminance is high, the output of the flash photometric unit 26 is unlikely to be saturated, and the preliminary light emission can be accurately measured.

FIG. 3 is a view showing the divided state of the photometric element 9 in comparison with the object field. The photometric element 9 divides almost the entire surface of the object field into five parts to perform photometry, and each photometric value B1
To B5 can be output.

FIG. 4 is a diagram showing the optical system of the flash photometer 26 and the divisional shape of the photometry area. The optical system of the flash photometric unit 26 re-images the subject image that has entered the shutter surface and formed an image on the light control element 13 by the triple light control lens 12 and divides the image into five areas S1 to S5. Then, the photoelectrically converted electric charges are accumulated. Here, S1
The relationship between each area and the number in S5 is shown in FIG.
It corresponds to each area and number of 1 to B5.

FIGS. 5 and 6 are flowcharts showing the operation of the flash control device for the camera according to the first embodiment.
First, in step S101, the camera is turned on by half-pressing the release switch 23 of the camera, this program is executed, and communication with the lens microcomputer 31 provided in the interchangeable lens 34 is performed. An initial process of reading information such as the open F value, focal length, exit pupil position, and the like is performed. Next, step S102
In the above, AF distance measurement is performed by the focus detection of the focus detection unit 17 until the calculated defocus amount becomes zero.
The lens optical system 36 is driven by the lens driving unit 35.

Further, in step S103, the photometric element 9
, And the brightness information of B1 to B5 is obtained, and based on the values, a steady light exposure calculation is performed by a known method to obtain an appropriate exposure value Bv. Further, an aperture value Av and a shutter value Tv at the time of shooting are calculated from the appropriate exposure value Bv and the film sensitivity value.

When the release switch 23 is fully pressed (S
104), when the release signal is input, the quick return mirror 2 is raised, and the aperture 10 is stopped down (S105).

In step S106, upon receiving an instruction for preliminary light emission from the sequence control unit 24, the light emission control unit 25 causes the gain setting unit 32 to set the amplifier / gain of the flash photometry unit 26. At this time, as a result of the photometry performed by the stationary light photometry unit 21, the gain of an area with high luminance is set low.

In S107, preliminary light emission is performed to cause the flash light emitting section 27 (flash light emitter 15 in FIG. 1) to emit chop light according to a predetermined guide number. And the flash photometer 2
Until the sum of the integrated values of the received light amount from the light receiving unit 6 reaches a predetermined value, the flash light emitting unit 26 continues to perform the chop light emission (S10).
8) Preliminary light emission is stopped (S109).

In step S110, the flash control unit 29 outputs the divided photometric area of the flash photometric unit 26 (the flash photometric unit 26 generated by the light reflected by the subject during the preliminary flash.
It is determined whether at least one of the outputs is outside the predetermined range. Specifically, the flash photometer 26
There are two cases: when at least one of the outputs is smaller than a preset first threshold value, and when at least one of the outputs is larger than a preset second threshold value. Here, the second threshold is a value larger than the first threshold.

The reason for this determination is that the flash photometer 2
This is because the dynamic range of 6 is narrower than required. That is, when the integral value (photometric value) of the preliminary light emission is smaller than the first threshold value, the data is too small and is buried in noise, and the measurement cannot be performed with sufficient accuracy. Conversely, when the integral value (photometric value) of the preliminary light emission is larger than the second threshold value, it is considered that the data has overflowed.

In the first embodiment, when the flash control unit 29 determines that at least one of the outputs of the flash photometry unit 26 is smaller than the first threshold value, the process proceeds to S111, and the photometry of the flash photometry unit 26 is performed. Reset the area gain. Specifically, only the amplifier gain of the corresponding photometry area of the flash photometry section 26 is reset to a large value, and the amplifier gains of the other photometry areas are set to small values.

In step S112, preliminary light emission by chop light emission is performed again, and photometry of preliminary light emission is performed. In the preliminary light emission, a stop signal for stopping the preliminary light emission is output (S114) when the amount of light received by the flash photometer 26 reaches a predetermined value (S113). By doing so, even if there is a photometric area where the amount of reflected light during the preliminary light emission is small, the preliminary light emission photometry can be performed accurately.

When the output of a photometry area is too small at the time of the first preliminary flash photometry, it is considered that, first, when there is no subject and there is no reflected light, secondly, for each photometry area, Because the reflectivity is too different, the stop signal described above is output in the photometry area having a high reflectance, and the preliminary light emission is stopped before sufficient charge accumulation is performed in the photometry area having a low reflectance. Is the case. In the first case, it is inevitable that the output is small because there is no actual reflected light, but in the second case, the output is simply buried in the output of the photometry area having a high reflectance.
Increasing the amount of preliminary light emission or the amplifier gain may allow correct photometry.

Therefore, in the second preliminary flash photometry,
The gain of the photometry area having a high reflectance is reduced, and only the gain of the photometry area having a low reflectance, that is, the output is too small at the first time is reset, and the preliminary light emission photometry is performed as in the first time. In this case, a stop signal is output only in the photometric area, and correct photometry can be performed.

If at least one of the outputs of the flash photometry unit 26 is larger than the second threshold value in the first preliminary photometry, the gain of the photometry area is reset to a low value, and the preliminary flash measurement is performed again. By performing flash photometry and preventing overflow, photometry can be performed accurately.

In step S116, the main light emission amount is calculated. The basic calculation is to compare the integrated value of the preliminary light emission with a certain reference value, and calculate how many times the intensity of the light emission from the preliminary light emission should reach the reference exposure amount on the imaging surface. Is transmitted to the light emission control unit 25, and the main light emission is performed by a multiple of the preliminary light emission amount.

In addition, values such as a photographing distance value are used to give a subtle flavor according to the state of the subject. For example, the reflectance of the subject can be estimated from the shooting distance, the preliminary light emission integral value, and the preliminary light emission guide number,
The main light emission amount is calculated by excluding an area having an abnormal reflectance from the divided object scenes. As a result, appropriate shooting can be performed even in a so-called "plain-through" subject where there is no subject, or in a scene where reflected light obtained by direct reflection of flash light on metal or the like enters.

Next, the shutter 11 is fully opened (S11).
7) The main light emission instruction is sent from the light emission control unit 25 to the flash light emission unit 2
7, the flash light emitting unit 27 performs imaging on the image sensor 14 while performing main light emission based on the main light emission amount calculated by the light emission amount calculation unit 30 (S118).
Then, by lowering the mirror and opening the aperture (S
119), a series of processing ends.

As described above, according to the first embodiment, the flash controller 29 controls at least one of the outputs of the flash photometer 26.
When it is determined that one is smaller than the first threshold value or larger than the second threshold value, the gain of the photometry area of the flash photometry unit 26 is reset and the preliminary light emission and the preliminary light emission photometry are performed again, so that the accuracy is improved. Photometry can be performed.

(Second Embodiment) FIG. 7 is a flowchart for explaining the operation of the flash control device for a camera according to the second embodiment. Note that each embodiment described below can be implemented with the same optical system and hardware configuration as the first embodiment, and some control such as flash control processing is different, so only the flowchart is shown. Will be explained. FIG.
Since steps S101 to S109 in the flowchart of (1) can be used in common, only the subsequent flows will be described.

In the second embodiment, the flash control unit 29
It is determined whether at least one of the outputs of the flash photometry unit 26 is smaller than the first threshold (S210). If the result is affirmative, the output of the flash photometry unit 26 in the corresponding photometry area is determined in advance. Is replaced with the given value (S211).
When the amount of return light reflected by the subject is small, the flash photometric unit 26 is out of the photometric range and the linearity is deteriorated. When the analog voltage output output from the flash photometer 26 is A / D converted and taken into the microcomputer,
When the output is small, the value may become zero.

The main light emission amount calculation unit 30 includes a flash photometer 26
From the output (preliminary light emission integral value) and the values of sensitivity, etc., the main light emission amount that gives an appropriate exposure value to the n-th metering area is calculated as in the following equation. The reciprocal of the output of the flash photometer 26 appears.

GNrtn [n] = GNpre√ (Const * G [n] / IG [n]) (1)

Here, GNrtn [n]: a guide number for giving an appropriate exposure value to the n-th area GNpre: a preliminary light emission guide number IG [n]: a flash light meter output (preliminary light emission integrated value), and n is each G [n]: Indicates the amplifier gain of the flash photometer, where n indicates a value for each area. Const: Reference value (constant) n: 1. . 5, Area number

Therefore, the A / D of the output of the flash photometer 26
If the value is 0, the main light emission amount diverges to infinity, and the calculation cannot be performed. Therefore, when the output of the flash photometry unit 26 is small, the value of the main light emission can be calculated by replacing the output with a predetermined value.
The value to be replaced is obtained in advance by an experiment. If it is an integer of 1 or more, it can be replaced as it is, but when calculating the reciprocal, by multiplying by 2 or 4, it is practically 0.5.
Or 0.25.

When at least one of the outputs of the flash photometry unit 26 is larger than the second threshold value in the first preliminary flash photometry, the gain of the photometry area is set low as in the first embodiment. Then, the pre-flash and the flash photometry are performed again so as not to overflow, so that the photometry can be performed accurately.

(Third Embodiment) FIG. 8 is a flowchart for explaining the operation of the flash control device for a camera according to the third embodiment. In the third embodiment, the flash control unit 29
Indicates that at least one of the outputs of the flash photometric unit 26 is the first
It is determined whether or not the light measurement area is smaller than the threshold value or larger than the second threshold value (S310). If the result is affirmative, the photometric area is not used in the calculation by the main light emission amount calculation unit 30. (S311). As a result, it is possible to prevent data that cannot be expected for accuracy from being used for calculation, and to obtain an appropriate main light emission amount.

The main light emission amount calculating section 30 calculates a preliminary light emission integrated value from the flash light metering section 26, a photometric value from the stationary light metering section 21,
The main light emission amount is calculated based on the shooting distance value from the lens microcomputer 31, the preliminary light emission guide number from the flash light emitting unit, the aperture value from the exposure calculation unit 22, the sensitivity value from the sensitivity setting unit 28, and the like. The value is output to the light emission control unit 27.
The basic calculation is to compare the preliminary light emission integral value with a certain reference value, calculate how many times the intensity of light emission from the preliminary light emission should reach the reference exposure amount on the imaging surface, and calculate the value. It communicates with the light emission control unit 25 to cause the main light emission to be performed by a multiple of the preliminary light emission amount. The main light emission amount can be obtained by the following equation when the number of divided regions is five.

GN = GNpre * √ (IGstop / (mval * Σ (IG [n] * Wt [n])))) (2)

Here, GN: a main light emission guide number for giving an appropriate exposure amount GNpre: a preliminary light emission guide number IGstop: a sum of each of the preliminary light emission integrated values IG [n] when a stop signal is output from the flash light meter mval: an effective area IG [n]: Preliminary light emission integrated value of each area, n is the number of the area Wt [n]: Weight of the area, weighted average for each area Wt that seeks the necessary light emission amount for the entire object scene
The sum of [n] is 1

As for a multiple of the preliminary light emission amount to be transmitted to the light emission control unit 25 and the flash light emission unit 27, a portion after √ in the equation may be extracted.

In the third embodiment, as described above, in the output (preliminary light emission integrated value IG) of the flash photometer 26, the photometry area smaller than the first threshold or larger than the second threshold is used. If there is, the area is excluded from the calculation of the above equation. When excluding one of the five areas, do not add the photometric area in Σ.
mval should be set to 4. By doing this,
An appropriate main light emission amount can be obtained.

(Fourth Embodiment) FIG. 9 is a flowchart for explaining the operation of a flash control device for a camera according to a fourth embodiment. In the fourth embodiment, the effective area used for the main light emission amount calculation is obtained based on the photometry result of the preliminary light emission (S411). In other words, the subject divided into five from the photometry value of the preliminary light emission, the shooting distance detected by the distance encoder 37 on the lens side, the guide number of the preliminary light emission, and the amplifier gain set in the flash photometric unit 26 Is determined.

More specifically, the amount of light emitted by the flash light emitting unit 27 during the preliminary light emission can be determined from the guide number of the preliminary light emission, and from this and the photographing distance, if the object has a wall having a uniform standard reflectance. In this case, the amount of light expected to be reflected and returned is required. This value is proportional to the amount of preliminary light emission and inversely proportional to the square of the shooting distance. On the other hand, the amount of light returned from the actual subject is obtained from the output of the photometry result of the preliminary flash and the amplifier gain,
From the difference between the two values, the average reflectance of each area of the subject is estimated.

Here, when a portion corresponding to a partial area of the subject is so-called “absence” and the amount of reflected light is extremely small, or when the reflected light is extremely large due to specular reflection on metal or the like, The reflectivity becomes extremely large or small. In the fourth embodiment, such a photometric area is detected by comparing it with a threshold value, and is not used for calculating the main light emission amount. That is, the light metering area can be excluded, and the light can be adjusted only by a subject having a medium reflectance, such as a person, so that a photograph with a preferable exposure can be obtained.

Next, based on the estimation of the reflectance, an effective area used for calculating the main light emission amount is obtained (S411).
It is determined whether or not the second preliminary light emission is necessary (S412).
Here, the output of the photometry result of the preliminary light emission of the area determined as the effective area is reviewed, and when at least one of them is smaller than a predetermined first threshold or larger than a second threshold, It is determined that the preliminary light emission and the preliminary light emission metering are necessary again.

The reason for this is to prevent a phenomenon in which the output is too small or too large and the photometry cannot be performed accurately, as in the first embodiment. The difference is
The necessity of preliminary light emission is determined again after the valid area is determined, so that it is possible to eliminate the need to re-meter the data of the invalid area.

When it is determined that re-preliminary light emission is necessary (S4
12, YES), and resets the amplifier gain of the flash photometer 26 to an appropriate value (S413), and the light emission controller 25
Makes the flash light emitting unit 27 perform preliminary light emission again (S4).
14), the flash photometer 26 measures the return light from the subject again (S415).

The main light emission amount calculation unit 30 uses the preliminary light emission photometric value obtained in this way for the calculation by supplementing the result of the previous preliminary light emission photometry value. Similar to the third embodiment, the main light emission amount calculation unit 30 calculates the main light emission amount based on the photometry result of the preliminary light emission in the effective area and communicates with the light emission control unit 25 and the flash light emission unit 27 ( S417). Thereafter, the shutter 11 is opened (S418), the subject is exposed on the image sensor 14 (S419), the mirror is lowered, and the aperture is opened (S420), thereby ending a series of processing. At this time, since the flash light emitting section 27 emits light at the obtained main light emission amount, a photograph with good exposure can be obtained.

(Modifications) Various modifications and changes are possible without being limited to the embodiments described above, and these are also within the equivalent scope of the present invention. (1) In S108 of FIG. 5, a description has been given of an example in which the stop signal is generated when the sum of the integrated values of the received light amounts reaches the predetermined value. However, when the number of times of the chop light emission reaches the predetermined number, the stop signal is generated. May be generated. (2) Although the example in which the image pickup device 14 is exposed has been described, the same can be applied to the case where a silver halide film is exposed.

[0068]

As described above in detail, according to the present invention, when at least one of the outputs from the flash photometric unit is out of the predetermined range, the gain of the photometric area is reset and the preliminary Since the flash and pre-flash metering were performed again, the output of the metering area was replaced with a predetermined value, and the output of the metering area was not used for the main flash amount calculation, etc. Now you can. For this reason, since the main light emission amount can be accurately calculated, there is an effect that the exposure accuracy at the time of flash light emission photographing can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an optical system of a flash control device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a signal flow of the flash control device according to the first embodiment.

FIG. 3 is a photometric element 9 of the flash control device according to the first embodiment.
FIG. 3 is a diagram showing a divided state of the object in comparison with an object scene.

FIG. 4 is a diagram showing an optical system of a flash photometry unit 26 of the flash control device according to the first embodiment and a divided shape of a photometry area.

FIG. 5 is a flowchart (part 1) for explaining the operation of the flash control device according to the first embodiment;

FIG. 6 is a flowchart (part 2) for explaining the operation of the flash control device according to the first embodiment;

FIG. 7 is a flowchart illustrating an operation of a flash control device according to a second embodiment.

FIG. 8 is a flowchart illustrating an operation of a flash control device according to a third embodiment.

FIG. 9 is a flowchart illustrating an operation of a flash control device according to a fourth embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 photographing lens 2 main mirror 3 finder screen 4 condenser lens 5 pentaprism 6 eyepiece 7 photometric prism 8 photometric lens 9 stationary light photometric element 10 aperture 11 shutter curtain 12 flash photometric lens (light control lens) 13 flash photometric element (Light control element) 14 Image pickup element 15 Flash light emitting section 16 Submirror 17 Autofocus element (focus detection section) F1 to F5 Focus adjustment area B1 to B5 Steady light metering area S1 to S5 Flash metering area

Claims (6)

[Claims] 1. A flash light emitting unit for performing main light emission at the time of photographing and a preliminary light emission before photographing, a flash light metering unit for dividing reflected light from a subject by the preliminary light emission to measure an object field, and the flash light If at least one of the outputs from the photometric unit is out of the predetermined range, the gain of the photometric area of the flash photometric unit whose output is outside the predetermined range is reset, and the preliminary light emission by the flash light emitting unit and the A flash control unit comprising: a flash control unit that controls preflash measurement by the flash photometry unit again. 2. A flash light emitting section for performing main light emission at the time of photographing and preliminary light emission before photographing, a flash light metering section for dividing reflected light from a subject by the preliminary light emission to measure the object field, and the flash light When at least one of the outputs from the photometry unit is out of the predetermined range, control is performed such that the output of the photometry area of the flash photometry unit whose output is out of the predetermined range is replaced with a predetermined value set in advance. A flash control device comprising: a flash control unit. 3. A flash light emitting section for performing main light emission at the time of photographing and preliminary light emission before photographing, a flash light metering section for dividing reflected light from a subject by the preliminary light emission to measure a subject field, and the flash light. A main light emission amount calculation unit that performs a calculation for controlling main light emission based on an output of the light measurement unit; and when at least one of the outputs from the flash light measurement unit is out of a predetermined range, the output is within a predetermined range. A flash control unit, comprising: a flash control unit that controls the outside of the light metering area of the flash metering unit so as not to be used for the calculation of the main light emission amount calculation unit. 4. A flash light emitting section for performing main light emission during photographing and preliminary light emission before photographing, a flash light metering section for dividing reflected light from a subject by the preliminary light emission to measure the object field, and the flash light Based on the output of the photometry unit, an effective area determination unit that determines a photometry area to be used for main light emission control, and the output of the photometry area of the flash photometry unit determined to be valid by the effective area determination unit is out of a predetermined range. And a flash control unit that controls the preliminary light emission by the flash light emission unit and the preliminary light emission measurement by the flash light measurement unit again. 5. A stationary light metering unit that divides the brightness of the object scene by the constant light to measure the light intensity, a flash light emitting unit that performs a main light emission at the time of photographing and a preliminary light emission before photographing, The reflected light, a flash light meter that divides the object field to measure light, and based on the brightness of the steady light measured by the steady light meter, resets the gain of the light metering area of the flash light meter, A flash control unit for controlling to perform pre-flash photometry,
A flash control device comprising: 6. The flash control device according to claim 5, wherein the flash control unit has a gain in a photometric area of the flash photometric unit corresponding to an area where the luminance of the stationary light measured by the stationary light photometric unit is large. A flash control device, wherein control is performed such that preliminary light metering is performed.