JPH08171118A - Camera with built-in stroboscope - Google Patents

Abstract

PURPOSE: To provide a camera with a built-in stroboscope capable of photographing with a proper exposure by emitting strobe light with timing corresponding to the distance up to a subject, during the opening of a shutter set according the luminance of external light. CONSTITUTION: The camera with built-in stroboscope is provided with a photometry part 18 measuring the luminance in a photographing visual field, range- finding parts 14 and 16 measuring the distance up to a subject and strobe light control parts 20, 21a and 21b and the strobe light control parts control the strobe light in accordance with the result of range-finding by the range-finding parts 14 and 16, so that an exposure with the strobe light is a standard exposure, when the luminance of the measurement of the photometry part 18 is lower than that of a changeover, so that the exposure with the strobe light is the standard exposure or below and decreased stepwise as the luminance of the measurement becomes higher, when the luminance of the measurement is higher than that of the changeover.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera with a built-in strobe, which can shoot with a proper exposure amount by causing a strobe to emit light.

[0002]

2. Description of the Related Art When photographing a person or the like, the face becomes dark at the time of backlighting, or even if it is not backlit, for example, when the sun is directly above, a shadow is formed on the face,
There is a problem that the atmosphere as a photograph is impaired.

Therefore, in a conventional camera, in order to eliminate such a shadow of an object, the strobe is always made to emit light even during daytime when the brightness of the outside light is high, so that the strobe light is used for the exposure by the outside light. There is known a camera that employs a constant light emission method for adding a.

Therefore, a photograph is taken in a so-called over-exposure state. However, when a negative color film having a wide latitude against over-exposure is used, this constant light emitting type camera is preferred.

As a concrete example of a conventional camera with a built-in strobe, which uses such a constant light emission system, Japanese Patent Laid-Open No. 56-149
No. 022 publication is known. The conventional camera with a built-in strobe described in this document is equipped with a photosensitive element that measures the amount of ambient light around the subject (called ambient light), and controls the amount of strobe light emission based on the amount of light measured by this photosensitive element. ing.

More specifically, as shown in FIG. 10, when the ratio of external light to proper exposure (hereinafter referred to as exposure contribution rate) is 0%, in other words, the amount of external light is 0. When the value is%, control is performed so as to irradiate a strobe light with a light amount of an exposure contribution rate of 100% so that the film can be sufficiently exposed only by the strobe light.

When the amount of external light increases and the exposure contribution rate is between 0% and 75%, the amount of strobe light is gradually reduced within the range of exposure contribution rate 100% to 35%. Thus, the total exposure contribution rate of the external light and the strobe light is controlled to be almost 100%.

Furthermore, when the exposure contribution rate due to the amount of outside light exceeds 75%, the diaphragm in the camera is automatically adjusted to forcibly maintain the exposure contribution rate of outside light at 75%, and at the same time, the strobe light is used. The exposure contribution rate of the strobe light is maintained at 35% by automatically adjusting the amount of light to be constant. That is, the exposure contribution rate due to the amount of external light is 75%.
When it exceeds, the control is performed so that the total of the exposure contribution rate of the external light and the exposure contribution rate of the strobe light is approximately 10%.

Therefore, in the conventional camera with a built-in strobe, the total of the exposure contribution rate of the external light and the exposure contribution rate of the strobe light is controlled to be in the range of about 100%.

[0010]

However, the conventional camera with a built-in strobe maintains the amount of strobe light at an exposure contribution rate of 35% even when the brightness of external light is high. While the light amount on the subject surface increases, the light amount ratio on the background may relatively decrease, which causes a problem that the background feels dark and the atmosphere as a photograph is impaired.

Further, the exposure contribution rate of the strobe light is kept at 35% regardless of the distance to the subject, so that the area occupied by the subject with respect to the background is small when performing close-up photography such as close-up photography. Due to the increase in the size, the amount of light on the subject surface due to the strobe light is significantly increased, and there is a problem in that the subject becomes a photograph that appears white.

The present invention has been made in view of the above problems of the prior art, and provides a camera with a built-in strobe that automatically controls strobe light so that an object can be photographed with an appropriate exposure amount. The purpose is to

[0013]

In order to achieve such an object, the camera with a built-in strobe according to the present invention measures the shutter that also serves as a diaphragm blade provided in an imaging optical system, and measures the brightness of external light in a photographing field of view. A photometric unit for measuring, a distance measuring unit for measuring a distance to a subject in the photographing field of view, and a luminance of external light that provides optimum exposure during a predetermined shutter open period of the shutter that also serves as the diaphragm blade, as a reference external light luminance. Further, the exposure amount in the state where the reference external light luminance is obtained is set as the standard exposure amount, and the standard exposure amount is obtained when the image is captured under the external light having the luminance equal to or higher than the reference external light luminance. An automatic exposure mechanism for controlling the opening and closing of the shutter that also serves as the diaphragm blade, and further, the reference external light luminance is switched luminance, or a predetermined brightness lower or higher than the reference external light luminance by a predetermined value or a predetermined value. As the switching brightness, and when the brightness of the external light in the imaging field of view measured by the photometric unit is lower than the switching brightness, the exposure amount added by the predetermined strobe light becomes substantially equal to the standard exposure amount. like,
During the opening / closing operation of the shutter that also serves as the diaphragm blade, the strobe light is emitted at a timing corresponding to the distance measured by the distance measuring unit, or the strobe light is emitted with an emission amount corresponding to the distance measured by the distance measuring unit. On the other hand, when the brightness of the external light in the photographing field is equal to or higher than the switching brightness, the exposure amount added by the strobe light is the standard exposure amount or less and the brightness in the photographing field. So as to decrease stepwise as the shutter height increases, the strobe light is emitted at the timing corresponding to the distance measured by the distance measuring unit, or the distance measuring unit A strobe light control unit that emits the strobe light with a light emission amount corresponding to the distance measured in step 1 is provided.

Further, the strobe light control unit gradually reduces the amount of reduction of the exposure amount by the strobe light which is gradually reduced as the distance to the object measured by the distance measuring unit becomes shorter. It is configured to increase.

[0015]

According to the camera with a built-in strobe according to the present invention, when the brightness within the photographing field of view measured by the photometry unit is lower than the predetermined switching brightness, the strobe light control unit shoots the exposure amount by the strobe light. The optimum exposure amount (that is, the standard exposure amount) is controlled. Furthermore, by controlling the amount of exposure with this strobe light according to the distance to the subject measured by the distance measuring unit, overexposure (excessive overexposure) is prevented even when the distance to the subject is short. On the other hand, underexposure (excessive underexposure) is prevented even when the distance to the subject is large.

That is, when the brightness measured by the photometry unit is lower than the switching brightness, in other words, when the sufficient exposure amount cannot be obtained only by the external light, the standard exposure amount by the strobe light is set as the external light amount. The addition makes it possible to photograph a subject with an appropriate exposure amount.

Further, when the brightness in the photographing field of view measured by the photometry unit is equal to or higher than the switching brightness, the exposure amount by the strobe light is gradually decreased as the standard exposure amount is less than or equal to and the brightness in the photographing field becomes higher. Control to decrease. The control in this case is also performed according to the distance to the subject measured by the distance measuring unit.

That is, the exposure amount by the stroboscopic light is controlled so as to decrease stepwise as the brightness in the shooting field of view increases, so that the background of the subject is displayed even if the brightness in the shooting field of view is high. It solves the problem that the light quantity ratio is relatively lowered. As a result, the problem of the prior art that the background becomes dark and the atmosphere as a photograph is spoiled even when shooting is performed under high brightness is solved.

That is, in the conventional control, the amount of light added by the strobe light is kept constant when a sufficient amount of exposure is obtained only by the external light. Therefore, the ratio of the amount of background light to the subject is reduced. Although there is a problem that the image becomes relatively dark and the background looks dark, the control according to the present invention causes the exposure to be added by the strobe light as the brightness in the photographing field increases. Even if the brightness in the field of view is high, the problem that the ratio of the amount of light in the background to the subject is relatively low is solved because the amount of light is gradually reduced, and the background becomes dark and the atmosphere as a photograph is impaired. Solve the problem of being

Furthermore, according to the prior art, in photographing a subject at a short distance such as a close-up shot, the area occupied by the subject becomes larger than that of the background. Although there is a problem that it tends to become a white photograph, in the present invention, as described above, when the brightness in the shooting field of view is high at the time of shooting at a short distance, the exposure amount by the strobe light irradiation is high. Since the amount of light is controlled to be extremely small, the balance of the amount of light on the subject surface and the background is maintained, and the subject does not become a white photograph.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
~ It demonstrates with FIG. FIG. 1 is a perspective view showing the external appearance of a flash built-in camera according to an embodiment. From the figure,
In this flash built-in camera, a shutter button 11 is arranged at the upper end of a camera body 10 having a substantially rectangular parallelepiped shape, and a lens barrel 13 with a lens 12 is attached to the center of the front surface of the camera body 10. On the upper part of the front surface of the camera body 10, a light projector 14, a finder 15, a light receiver 16 and a strobe 17 are arranged from the left in the figure.

Here, the light projector 14 and the light receiver 16 constitute a distance measuring section for measuring the distance to the subject based on the principle of triangulation, for example.

On the right side of the lens barrel 13 on the front surface of the camera body 10, there is incorporated a photometric unit 18 for measuring the external light luminance within the field of view. The photometric unit 18 includes an entrance window 18a formed on the surface of the camera body 10, a lens 18b disposed inside the entrance window 18a, and a lens 18b.
A light receiving element 18c having a light receiving surface is provided near the image forming position of b.

The light receiving surface of the light receiving element 18c is the lens 18b.
Since the light receiving element 18c does not form a complete image of the subject on the light receiving surface of the light receiving element 18c, the light receiving element 18c detects the average outside light amount of the entire field of view including the object. To be done.

Further, the lens 12 inside the camera body 10
A shutter 19 that also serves as diaphragm blades is provided on the optical axis of to provide the exposure amount required for the film.

The strobe 17 is controlled to automatically emit strobe light in synchronization with the opening timing of the shutter 19. More specifically, the exposure amount on the subject surface is adjusted by delicately shifting the light emission timing of the strobe 17 with respect to the opening timing of the shutter 19.

This adjustment algorithm will be described with reference to the time chart of FIG. This time chart shows how much exposure amount can be obtained when the strobe 17 emits light at the timing after the shutter 19 is started.

From the figure, when the strobe light is emitted at the timing when the shutter 19 is started and time t _{1 has} elapsed, the aperture area of the shutter 19 is still small and the light flux for exposing the film is also small. Therefore, the exposure amount is small. On the other hand, when the strobe light is emitted at the timing when the shutter 19 is started and time t _{2 has} elapsed, the opening area of the shutter 19 is maximized, so that the luminous flux for exposing the film becomes large. For this reason,
The exposure dose at time t ₂ is almost twice as large as the exposure dose at time t ₁ . In this way, by shifting the temporal phase of the light emission timing of the strobe 17 with respect to the opening timing of the shutter 19, the exposure amount of the strobe 17 can be arbitrarily adjusted while keeping the light emission amount of the strobe 17 constant. You can

Further, the block diagram of FIG. 3 shows a specific structure of the strobe light control unit for controlling the light emission timing of the strobe 17. This strobe light control unit is used for the projector 1
4 and the distance to the object measured by the light receiver 16 and the external light brightness within the field of view measured by the photometry unit 18, the emission timing of the strobe light for obtaining the optimum exposure for shooting is controlled. . The strobe light control unit is realized by so-called program control in which the CPU 20 executes the control program 21a written in the ROM 21.

A half-press signal and a full-press signal are applied to the CPU 20 from the shutter button 11. Upon receiving the half-press signal from the shutter button 11, the CPU 20 gives a control signal for measuring the distance to the subject to the light projector 14, and causes the photometric unit 18 to measure the external light luminance in the photographing field of view. Give a control signal. With these control signals, the light projector 14 (and the light receiver 16) and the photometry unit 18 perform distance measurement and photometry, and give these measurement results to the CPU 20.

Upon receiving the full-press signal from the shutter button 11, the CPU 20 provides the strobe 17 with a control signal for firing a strobe and the shutter 19 with a control signal for opening and closing the shutter.

Next, based on the control program 21a, C
FIG. 4 shows a flow of processing of light emission timing control performed by the PU 20.
This will be described with reference to the flowchart of.

First, when the power switch is turned on, CP
Initial processing such as clearing the memory built in U20 and setting the I / O port is performed (step 100). Then, the process waits until one of the switches is activated (step 102). The switches include a self-timer switch and a zoom switch in addition to the shutter button 11. When any switch is activated (step 104), which switch is activated is detected (step 106), and in the case of switches other than the shutter button 11, processing is performed for each switch (step 1).
08).

In step 106, the shutter switch 11
When it is detected that is pressed halfway, the remaining amount of the power supply battery is checked (step 110). Next, CPU2
A signal from 0 is given to the photometric unit 18, and the photometric unit 18 measures the external light brightness in the photographing field of view (step 11).
2). Further, a signal from the CPU 20 is given to the light projecting device 14, and the light projecting device 14 and the light receiving device 16 measure the distance to the object (step 114). This measurement is performed, for example, based on the principle of triangulation. And step 1
The exposure value EV which is the control value of the shutter 19 is calculated by substituting the apex value (BV) of the external light luminance and the apex value (SV) of the film sensitivity obtained in step 12 into the following equation (step 116).

EV = SV + BV ... The calculation of the EV value determines the combination of the shutter speed and the aperture value for obtaining the exposure amount required for photographing,
At the time of photographing in step 126, which will be described later, the opening / closing drive of the shutter that also serves as the diaphragm blade is controlled based on the shutter speed and the aperture value.

Next, the AV value for determining the timing for firing the strobe 17 is calculated (step 11).
8). The AV value is a value corresponding to the opening area of the shutter 19 when the strobe 17 is made to emit light. In other words, if the AV value is obtained, the shutter 19 is started when the shutter 19 is started and the opening area gradually increases.
Stroke 1 from the AV value because you can see if
The light emission timing of 7 can be obtained. In the calculation of the AV value, first, the distance (D) to the subject obtained in step 107 is substituted into the following equation, and the guide number (GNo.) In ISO 100 is substituted into the equation, and DV is calculated.
Value and GV value are obtained.

DV = -2log ₂ D ... GV = 2log ₂ GNo. Next, an OFS value which is a correction value is obtained from the correction table 21b written in the ROM 21. Correction table 21b
As shown in the example of FIG. 5, is a table in which the external light brightness in the field of view and the distance to the subject are parameters. In this example, the external light brightness in the field of view is (0 to B1, B1 to
B2, B2-B3, B3-) are divided into four stages, and the distance to the subject is (closest to D1, D1 to D2, D2 to D3, D).
It is divided into 4 stages of 3 to) (however, B1 <B2 <B
3, D1 <D2 <D3). In this embodiment, the closest distance is 0.35 m, the distance D1 is 1.3 m, and the distance D2 is
Is 3.0 m and the distance D3 is 8.9 m.

Then, the OFS value can be obtained from the external light brightness in the field of view measured in step 112 and the distance to the object measured in step 114. For example, when the distance is between D1 and D2 and the brightness is between B2 and B3, OFS = 1/4. When the distance is D3 or more and the brightness is between B1 and B2, OFS = 1. By substituting this OFS value into the following equation, FL
The value is obtained.

FL = log ₂ OFS ... By substituting the DV value, GV value, FL value and film sensitivity (SV) thus obtained into the following equation, AV
A value is obtained (step 118).

AV = GV + SV + DV-FL-5 ... Next, the shutter button 11 is further pressed from the half-pressed state until the full-pressed state is reached (steps 120 and 122), and the shutter button 11 is not fully pressed. If the finger is released from the shutter button 11 and returns to the original position, step 10
The process is returned to the process of 2. Also, the shutter button 11
When is fully pressed, the photographing optical system including the lens barrel 13 and the like is set to the focused state (step 124), and then the shutter 19 is opened and closed to take a photograph.

The opening / closing control of the shutter 19 is performed in step 1.
It is performed based on the shutter speed and the aperture value determined based on the EV value calculated in 16. Then, when the opening area of the shutter 19 reaches the AV value calculated in step 118, the strobe 17 emits light (step 126). Due to the light emission of the strobe 17, sufficient exposure for photographing can be obtained.

After the shutter 19 is closed, the lens set to the in-focus state is moved to the initial position and made to stand by (step 128), the film is further fed (step 130), and then the strobe 17 is charged. Do (Step 1
32). Then, while the shutter button 11 is half-pressed, the process waits (step 134), the finger is released from the shutter button 11, the shutter button 11 returns to the original state, and then the process returns to step 102.

A feature of this embodiment is that the exposure amount by the strobe 17 is adjusted based on the correction table 21b when the AV value is calculated in step 118.

As shown in FIG. 5, the correction table 21b divides the distance to the subject and the external light intensity in the photographing field into four stages, and the OFS value, which is the correction value of the exposure amount by the strobe 17, is finely assigned in each stage. There is. Basically, when the external light brightness is B1 or less, the exposure amount is insufficient only by the external light brightness, so that the correction value OFS = 1 (FL = 0EV) that does not decrease the exposure amount by the strobe 17 is assigned. There is. When the external light brightness is B1 or more, the correction value OFS for reducing the exposure amount by the strobe 17 is 1/2.
.About.1 / 8 (FL = -1 EV to -3 EV) is allocated. The amount of decrease at this time is adjusted to be large when the distance is short.

The relationship between the exposure amount of the strobe 17 corrected by the correction table 21b and the exposure amount of the external light in the photographing field will be described with reference to the graphs of FIGS. These graphs show that the film speed is ISO100.
This is for the case of (SV = 5), and each distance (closest to D1, D1 to D2, D2) in the correction table 21b.
D3, D3 ~). Further, the horizontal axis of each figure shows the external light luminance (apex value), and the vertical axis shows the external light luminance that gives the optimum exposure amount in the predetermined opening period of the diaphragm blade / shutter 19 as the reference external light luminance. At the same time, the exposure amount in the state where the reference outside light brightness is obtained is set as the standard exposure amount, and the respective light amount ratios (referred to as exposure contribution amounts) of the outside light and the flash light contributing to this standard exposure amount (100%) Show.

Further, the outside light brightness B1 is set to a value equal to the above-mentioned reference outside light brightness, or a value lower than the reference outside light brightness by a predetermined brightness, or a predetermined value lower than the reference outside light brightness. The brightness is set to a high value, which is called switching brightness.

First, the relationship between the exposure amount by the strobe 17 and the exposure amount by external light when the distance to the subject is D1 or less will be described with reference to FIG. According to the graph of the figure, when the external light brightness is BV1 or less, the time for which the shutter 19 is open becomes the camera shake prevention limit and is constant. Therefore, the external light alone cannot provide 100% exposure necessary for shooting. . Therefore, the exposure amount of the external light continues to increase until the external light brightness reaches BV1. When the external light brightness becomes BV1 or higher, the shutter 19 is controlled so that the exposure amount by the external light is 1 or less.
Adjusted to maintain 00%. Therefore, the amount of exposure by the external light becomes constant when the external light brightness is BV1 or higher.

On the other hand, when the external light luminance is B1 or less, the exposure amount by the strobe 17 is 10 necessary for photographing.
The exposure amount is 0%, and when the external light luminance is increased to B1, B2, and B3, it is decreased by 1/2 each. this is,
0 to B1, B1 when the distance to the subject is less than D1
To B2, B2 to B3, and B3 to external light luminance, OFS = 1 (FL = 0 EV) and OFS = 1/2 (F
L = -1EV), OFS = 1/4 (FL = -2EV),
OFS = 1/8 (FL = -3EV) is the correction table 2
This is because it is assigned to 1b.

As described above, when the distance to the subject is as short as D1 or less, the exposure amount by the strobe 17 decreases stepwise as the external light brightness increases. if,
When the external light brightness is high and the exposure amount by the strobe 17 is constant, the ratio of the amount of light of the background to the subject is reduced, and a photograph in which the background feels dark is taken. In the present embodiment, the exposure amount by the strobe 17 decreases stepwise as the external light brightness increases, and therefore the light amount ratio of the background to the subject does not decrease even when the external light brightness is high. Therefore, a photograph is taken in which the background is not dark even under high brightness, and the atmosphere of the photograph is not impaired. As will be described later,
Even when the distance to the subject is D1 or more, the exposure amount by the strobe 17 is adjusted to decrease stepwise as the external light brightness increases, so that the same effect can be obtained even if the distance to the subject increases. can get.

Further, when the distance to the subject is as short as D1 or less, the amount of exposure by the strobe 17 when the external light luminance is B3 or more is extremely small. When shooting a subject at a short distance, the area occupied by the subject is larger than that of the background, and thus the light amount on the subject surface and the background are out of balance, and the subject tends to appear white. In this embodiment,
When the distance is short and the brightness of outside light is high, the exposure amount by strobe light irradiation is controlled to be extremely small, so the light amount on the subject surface and the background are balanced, and the subject appears white. It will never be a photo.

Next, the relationship between the exposure amount by the strobe 17 and the exposure amount by external light when the distance to the subject is between D1 and D2 will be described with reference to FIG. From the graph in the figure,
The amount of exposure to external light is the same as the graph in FIG. On the other hand, the amount of exposure by the strobe 17 is such that the external light brightness is B1.
In the following cases, the exposure amount is 100% necessary for photographing, and when the external light brightness is increased to B1 and B2, 1 / each is obtained.
It is decreasing by two. The difference from the graph of FIG. 6 is that the exposure amount by the strobe 17 is 1 even if the external light brightness becomes B3.
This is a point that has not decreased to / 2. In this graph, since the distance to the subject is as long as D1 or more, even if the external light luminance is as high as B3 or more, the problem that the balance of the light amount on the subject surface and the background as described above is lost does not occur. Absent. For this reason, when the external light brightness is B3, the fine processing such as reducing the exposure amount by the strobe 17 to 1/2 is not performed.

Next, the relationship between the exposure amount by the strobe 17 and the exposure amount by external light when the distance to the subject is between D2 and D3 will be described with reference to FIG. The graph in this figure is shown in Fig. 7.
The difference between the graphs is that the exposure amount by the strobe 17 is not reduced to 1/2 even if the external light brightness becomes B1. Therefore, the exposure amount of the strobe 17 having the external light brightness of B1 is twice as large as that in the graph of FIG. But,
Since the distance to the subject is D2 or more, which is even longer than that in the graph of FIG. 7, the problem of the imbalance of the light amounts of the subject surface and the background as described above does not occur.

Next, the relationship between the exposure amount by the strobe 17 and the exposure amount by external light when the distance to the subject is D3 or more will be described with reference to FIG. In the graph of the figure, the exposure amount by the strobe 17 is 10 until the external light brightness becomes B2.
The exposure amount is set to 0%, and the flash 17 is controlled to stop emitting light when the external light brightness is B2 or higher. in this way,
The strobe light emission is stopped with the external light brightness of B2 or more because the strobe light is hard to reach when the distance to the subject is as long as D3 or more, and the strobe light 1 is used when the external light brightness is high as B2 or more.
This is because even if the light emission of No. 7 is stopped, it has almost no effect on the photography.

The case where the film sensitivity is ISO100 has been described above, but similar effects can be obtained for other sensitivities by sliding the BV value.

The present invention is not limited to the embodiments described above, and various modifications can be made. For example, in the present embodiment, as shown in FIG. 2, the exposure amount is adjusted by slightly shifting the light emission timing of the strobe 15 from the shutter timing (shifting the phase in time). The exposure amount may be adjusted by keeping the light emission timing constant and variably controlling the light emission amount of the strobe 15.

Although the distance to the subject is measured by the active method using the light projector 14 and the light receiver 16, a passive method may be used.

[0057]

As described above in detail, in the camera with a built-in strobe according to the present invention, the photometry unit for measuring the brightness within the field of view, the distance measurement unit for measuring the distance to the object, and the photometry unit are used. If the brightness in the field of view is lower than the switching brightness,
The strobe light is controlled so that the exposure amount by the strobe light becomes the standard exposure amount, and when the brightness in the shooting field of view is equal to or higher than the switching brightness, the exposure amount gradually decreases as the brightness in the shooting field of view increases. And a strobe light control unit for controlling strobe light.

As described above, since the exposure amount by the strobe light is controlled to decrease stepwise as the brightness in the photographing field of view increases, even if the brightness in the photographing field of view is high, the amount of light of the background to the subject is high. The ratio never goes down. Therefore, a photograph is taken in which the background is not darker than the subject even under high brightness, and the atmosphere as a photograph is not impaired.

Further, when the distance is short and the brightness in the field of view is high, the exposure amount by the irradiation of the strobe light is controlled to be extremely small, so that the light amount balance between the object surface and the background is maintained. , The subject will not be a white photograph.

[Brief description of drawings]

FIG. 1 is a perspective view showing the external appearance of a flash built-in camera according to an embodiment.

FIG. 2 is a time chart showing the relationship between the shutter opening timing and the strobe light emission timing.

FIG. 3 is a block diagram showing a specific configuration for performing strobe light emission timing control.

FIG. 4 is a flowchart showing a flow of processing of light emission timing control.

FIG. 5 is a diagram showing a correction table.

FIG. 6 is a diagram showing a relationship between an exposure amount by a strobe and an exposure amount by external light within a field of view when a distance to a subject is D1 or less.

FIG. 7 is a diagram showing a relationship between an exposure amount by a strobe and an exposure amount by external light within a photographing field when a distance to a subject is D1 to D2.

FIG. 8 is a diagram showing a relationship between an exposure amount by a strobe and an exposure amount by external light within a photographing field when a distance to a subject is D2 to D3.

FIG. 9 is a diagram showing a relationship between an exposure amount by a strobe and an exposure amount by external light within a field of view when a distance to a subject is D3 or more.

FIG. 10 is a diagram showing a relationship between an exposure amount by external light and an exposure amount by a strobe in a conventional camera with a built-in strobe.

[Explanation of symbols]

14 ... Projector (distance measuring unit), 16 ... Light receiver (distance measuring unit), 1
8 ... Photometry unit, 20 ... CPU (strobe light control unit), 21
a ... Control program (strobe light control unit), 21b ... Correction table (strobe light control unit).

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location G03B 7/097 15/05

Claims (2)

[Claims] 1. A shutter that is also used as an aperture blade provided in an imaging optical system, a photometry unit that measures the brightness of external light within a shooting field of view, and a range finding unit that measures the distance to a subject within the shooting field of view. With the standard external light intensity as the standard external light intensity and the external light intensity with which the optimum exposure is obtained in the predetermined shutter open period of the diaphragm blade shutter, and with the standard external light intensity, When shooting under external light with a brightness equal to or higher than the reference external light brightness, an automatic exposure mechanism that controls the opening and closing of the shutter that also serves as the diaphragm blade to obtain the standard exposure amount, and the reference external light brightness are switched. The switching brightness is set to the brightness or a predetermined brightness lower than the reference external light brightness by a predetermined value or a value higher than the reference external light brightness, and the brightness of the external light in the photographing field of view measured by the photometric unit is the cutoff brightness. Corresponding to the distance measured by the distance measuring unit during the opening / closing operation of the shutter that also serves as the diaphragm blade so that the exposure amount added by the predetermined strobe light becomes substantially equal to the standard exposure amount when the brightness is lower than the brightness. When the strobe light is emitted at the timing, or the strobe light is emitted at a light emission amount corresponding to the distance measured by the distance measuring unit, and the brightness of the external light in the photographing field is equal to or higher than the switching brightness. During the opening / closing operation of the shutter that also serves as the diaphragm blade, the exposure amount added by the strobe light is gradually decreased as the standard exposure amount is equal to or less than the standard exposure amount and the brightness in the photographing field becomes higher, The strobe light is emitted at a timing corresponding to the distance measured by the distance measuring unit, or the strobe light is emitted with a light emission amount corresponding to the distance measured by the distance measuring unit. Built-in flash cameras, characterized by comprising: a flash light control unit for emitting a volume light. 2. The strobe light control unit gradually increases the reduction amount of the exposure amount by the strobe light which is gradually reduced as the distance to the subject measured by the distance measuring unit becomes shorter. The camera with a built-in strobe according to claim 1, wherein the camera has a built-in strobe.