JPH08248467A - Camera provided with stroboscope - Google Patents

Abstract

PURPOSE: To prevent a failure of photographing a picture having color fogging caused by an artificial light source. CONSTITUTION: The camera provided with a stroboscope is provided with at least an artificial light source detecting part 1 detecting the presence of the artificial light source, based on a pulsating current from the artificial light source and an arithmetic control part 4 calculating the ratio of a stroboscope light quantity to the light quantity of surrounding light including the light of the artificial light source and controlling the quantity of light emitted from a stroboscope light emitting part 5 based on the result of the calculation so as to prevent color temp. inherent to the artificial light source from affecting the exposure state of a film when the presence of the artificial light source is detected by the artificial light source detecting part 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a strobe camera which detects an artificial light source and automatically emits light.

[0002]

2. Description of the Related Art Conventionally, when photographing with a strobe device by a camera, a so-called color cast, which is influenced by an artificial light source such as a fluorescent lamp, is generated depending on the photographing environment, which is a problem. . Then, in order to solve this problem, the following various techniques have been proposed.

That is, for example, in Japanese Laid-Open Patent Publication No. 6-35026, an optical sensor detects light to detect a pulsating current of photocurrent,
A technique for causing a strobe to emit light is disclosed. further,
Japanese Patent Laid-Open No. 63-129797 discloses a technique for detecting the content rate of a ripple component related to a light source and controlling the strobe light emission condition. That is, in this technique, the strobe is caused to emit light for color balance correction in view of the fact that the color balance is impaired when the artificial light source content is high.

Also, in the "Japan Camera Separate Volume Polaroid World", when it is dark, it is exposed with 100% strobe light,
In a bright distant view, the strobe emits light, but it is exposed by 100% natural light, giving a bright close-up shot (60 cm to 4.25 m).
Then, the ratio of natural light 75% and strobe light 25% (product SL
In R680, the ratio of natural light 60% and strobe light 40%) is used for exposure. In addition, a technique for automatically adjusting the amount of strobe light, the shutter speed, and the aperture according to the brightness and the shooting distance has been proposed.

[0005]

However, in the technique disclosed in the above-mentioned Japanese Patent Laid-Open No. 6-35026,
Nothing is described about the control of the amount of stroboscopic light emitted when an artificial light source is detected, and nothing about the balance amount of the stationary light and the stroboscopic light by the artificial light source is described. If the flash is fully fired,
Nothing is disclosed about the content of minimizing the strobe light emission amount in consideration of the balance amount of the stationary light and the strobe light and suppressing the energy consumption.

Furthermore, in the technique disclosed in Japanese Patent Laid-Open No. 63-129797, there is no mention of the balance amount between the stationary light and the strobe light of the artificial light source when the artificial light source is detected.

Further, according to the above "world of polaroids", there is no mention of emitting a minimum amount of light when it is necessary to cancel the fogging of the artificial light source. The present invention has been made in view of the above problems, and an object of the present invention is to reduce energy consumption of a strobe and prevent failure of taking a photograph in which a color cast occurs due to an artificial light source.

[0008]

In order to achieve the above object, a camera with a strobe according to a first aspect of the present invention comprises:
Artificial light source detection means for detecting the presence or absence of the artificial light source based on the pulsating flow from the artificial light source, and when the artificial light source is detected by the artificial light source detection means, the color temperature peculiar to the artificial light source exposes the film. In order not to adversely affect the state, a light amount ratio calculating means for calculating the light amount ratio between the strobe light amount and the ambient light including the light of the artificial light source, and the light emission amount of the strobe based on the output of the light amount ratio calculating means. And a stroboscopic light emission amount control means for controlling.

In the strobe camera according to the second aspect, the artificial light source detecting means for detecting the presence or absence of the artificial light source based on the pulsating flow from the artificial light source, and the artificial light source detecting means for detecting the presence of the artificial light source. In this case, a light amount ratio calculating means for calculating a light amount ratio between the strobe light amount and the ambient light including the light of the artificial light source so that the color temperature specific to the artificial light source does not adversely affect the exposed state of the film, Strobe light emission amount control means for controlling the light emission amount of the strobe based on the output of the light amount ratio calculation means, and warning that the exposure state of the film will be adversely affected when the output of the light amount ratio calculation means is not within a predetermined range And a color cast warning means for controlling the color cast.

Further, in the camera with strobe according to the third aspect, the artificial light source detecting means includes a field brightness detecting means for detecting brightness of a field due to at least one of the stationary light and the artificial light source light, And a pulsating flow presence / absence detecting unit for detecting the presence / absence of a pulsating flow from the artificial light source based on the output of the field brightness detecting unit.

[0011]

That is, in the strobe camera according to the first aspect of the present invention, the presence or absence of the artificial light source is detected by the artificial light source detecting means based on the pulsating flow from the artificial light source, and the artificial light source detecting means is detected by the light quantity ratio calculating means. By the artificial light source is detected when there is an artificial light source, the light amount ratio of the strobe light amount and the ambient light including the light of the artificial light source is calculated so that the color temperature peculiar to the artificial light source does not adversely affect the exposed state of the film,
The strobe light emission amount control means controls the strobe light emission amount based on the output of the light amount ratio calculation means.

In the strobe camera according to the second aspect, the presence or absence of the artificial light source is detected by the artificial light source detecting means based on the pulsating flow from the artificial light source, and the artificial light source detecting means detects the artificial light source by the light quantity ratio calculating means. When it is detected that the artificial light source has a color temperature that does not adversely affect the exposed state of the film, the light amount ratio between the strobe light amount and the ambient light including the artificial light source light is calculated, and the strobe light emission amount is calculated. The control means controls the light emission amount of the strobe based on the output of the light quantity ratio calculating means, and when the output of the light quantity ratio calculating means is not within the predetermined range by the color cast warning means, the exposed state of the film is adversely affected. Is warned.

Further, in the strobe-equipped camera according to the third aspect, in the artificial light source detecting means, the brightness of the object field by at least one of the stationary light and the artificial light source light is detected by the object field brightness detecting means. The presence / absence of a pulsating flow from the artificial light source is detected by the pulsating flow presence / absence detecting unit based on the output of the field brightness detecting unit.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. First, FIG. 1 shows a conceptual diagram of a camera with a strobe according to the present invention, which will be described. As shown in the figure, the outputs of the artificial light source detection unit 1, the photometry unit 2, and the distance measurement unit 3 are connected to the inputs of the arithmetic control unit 4, and the output of the arithmetic control unit 4 is the strobe light emitting unit 5. , The exposure unit 6 and the focusing unit 7, respectively.

In such a configuration, the artificial light source detection unit 1 detects the pulsation of natural light such as sunlight and the light contained in the artificial light source, distinguishes between the natural light and the artificial light source, and the calculation result is calculated by the operation control unit. Output to 4. The photometric unit 2 detects the brightness of the subject and the background and outputs the brightness information to the calculation control unit 4. The distance measuring unit 3 detects the focus shift amount of the subject, calculates the distance to the subject from the focusing lens position and the shift amount,
The distance information is output to the arithmetic control unit 4. Arithmetic control unit 4
Outputs a control signal to the focusing unit 7 based on the result of the distance measuring unit 3 to calculate focusing / non-focusing. Further, from the results of the artificial light source detection unit 1, the photometry unit 2, and the distance measurement unit 3, the presence or absence of the strobe light emission, the light emission amount, and the shutter speed are calculated to determine the aperture, and the strobe light emission unit 5, the exposure unit 6, and the focusing unit 7 are determined. Output. The strobe emission unit 5 controls strobe emission according to the output of the calculation control unit 4. The exposure unit 6 controls the exposure according to the output of the calculation control unit 4. The focusing unit 7 drives and controls a focusing lens (not shown) according to the output of the calculation control unit 4.

Next, FIG. 2 shows the configuration of a circuit for detecting the pulsation of the artificial light source using a photometric circuit, and will be described. In the figure, VREF of the IFIC 11 that generates the reference voltage VREF
The output of the generation circuit 12 is connected to the collector of the transistor 24 via the resistors 20 and 21, and is grounded to the ground via the emitter. The base of the transistor 24 is C
It is connected to the output port VSFT of PU10. Further, the connection ends of the resistors 20 and 21 are connected to the reference voltage input VAD for AD conversion of the CPU 10.

When a high level "H" signal is input to the port VSFT of the CPU 10, the transistor 24
Is turned on, the transistor 24 becomes saturated, the collector and the emitter of the transistor 24 become conductive, and the potential is almost the same as the ground. At this time, the voltage VREF ′ obtained by dividing the voltage VREF by the resistors 20 and 21 is applied to the port VAD. On the other hand, CPU
When a low level "L" signal is input to the above-mentioned port VSFT of 10, the transistor 24 is turned off and the collector and emitter of the transistor 24 become non-conductive. At this time, since only a weak current flows through the resistor 20, the potential difference generated is small and the voltage VREF is applied to the port VAD.

Since the photometric circuit 13 of the IFIC 11 is a compression type photometric circuit which is generally used, its detailed description is omitted here. The voltage signal output from the photometric circuit 13 is directly input to the port AD1 of the CPU 10. Further, it is input to the port AD2 of the CPU 10 via the diode 22. Then, it is grounded through the resistor 23. A potential difference of about 0.6 V is generated across the diode 22.

The relationship between the voltage VREF, the divided voltage VREF ', and the signals at the ports AD1 and AD2 will be described with reference to FIG. Ordinary photometry may have a low resolution, so
It is necessary to increase the voltage VREF to widen the photometric range. A signal having a voltage lower than AD1 by 0.6 V is generated at the port AD2. Since the pulsation of the photocurrent of the artificial light source is extremely small, the amplitude is actually not very large as shown in FIG. 3, but is very small. Since the port AD2 wants to detect this amplitude as large as possible, the voltage VREF is adjusted by dividing the voltage VREF to an appropriate value with the resistors 20 and 21 (VREF ').

Further, it is necessary to lower the signal by using one stage of the diode 22 so that the port AD2 shows a valid value within the range of the voltage VREF. If the diode 22 does not fit within the voltage VREF 'even if it is used in one stage, another one-stage diode can be inserted in series to extract a signal which is lowered by about 1.2V from the port AD1.

As described above, the pulsation of the photocurrent can be efficiently detected by adjusting the voltage division of the voltage VREF and the shift of the voltage signal by the diode. In the present embodiment, the photometric sensor 14 is shared to detect the field brightness and the artificial light source. However, the photometric sensor 14 and an artificial light source having a different sensitivity from the photometric sensor are used to detect the artificial light source. It is possible to do However, in this case, it is necessary to adjust the voltage signal input to the CPU 10 according to the sensitivity of the optical sensor.

Hereinafter, with reference to the flowchart of FIG.
The main sequence of the camera with a strobe will be described. When the operation is started, the CPU 10 performs initial setting required for a series of camera operations (step S1). Then, when the shutter button is pressed halfway, that is, when the 1st release switch is turned on (step S2), the CPU 10 gives an integration start signal to an AFIC (not shown) to start integration (step S3).

Next, when an integration completion signal is output from the AFIC upon completion of integration (step S4), the CPU 10
Determines that the integration is completed, fetches the AF information from the AFIC, obtains the focus shift amount, and obtains the drive direction and drive amount of the focusing lens. If it is in focus, a focus signal is output. At this time, the distance to the subject is calculated from the drive amount of the focusing lens. Further, the integration time is converted into the brightness information of the AF area (step S5).

Subsequently, the CPU 10 determines whether or not the focus is achieved (step S6). If the focus is not achieved, the step S5 is performed.
After driving the focusing lens based on the driving direction and the driving amount of the focusing lens obtained in (step S7), the process returns to step S2 and the above operation is repeated. On the other hand, if the subject is in focus, the process proceeds to step S8 (step 6), and photometric calculation is performed to obtain an appropriate exposure value from the photometric value (step S).
8). Details of this will be described later with reference to FIG.

Then, the second button is pressed by fully pressing the release button.
The state of the release switch is detected, and when the switch is off, the process returns to step S2. On the other hand, 2
When the nd release switch is fully pressed (step S
9), the CPU 10 sets the TV value and AV obtained in step S8.
Exposure is performed based on the value (step S10), one frame of the exposed film surface is wound up, and the process returns to step S2 (step S11).

Next, referring to the flowchart of FIG. 5, the subroutine "photometric calculation" executed in step 8 above.
The process will be described. When this sequence starts,
The subroutine "photometry" is executed, and the CPU 10 uses the photometric sensor 14 to convert the photocurrent of the sensor by the IFIC 11, and obtains the photometric values of the center and the periphery of the field by the analog signal (step S21). The processing of this subroutine "photometry" will be described later with reference to FIG.

Subsequently, the CPU 10 executes a subroutine "light source detection" to detect the pulsation of photocurrent using the photometric sensor 14 and the IFIC 11 (step S22). The processing of this subroutine "light source detection" will be described later with reference to FIG. Then, the weighted average photometric value BVAVE of the central portion is obtained from the photometric values of the center and the periphery of the object field obtained in step S21 by the following equation (step S23).

[0028]

[Equation 1]

Subsequently, the CPU 10 clears the strobe light emission request flag to "0" (step S24), and if the light source detection flag is "0", proceeds to step S27 and sets the light source detection flag to "1". If it is, the flash light emission request flag is set to "1" and then the process proceeds to step S27 (steps S25 and S26). The light source detection flag is set to "1" when the artificial light source is detected in step S22, and is set to "0" when the artificial light source is not detected. Next, the CPU 10 determines the center-weighted average photometric value BVAVE and the film sensitivity SV obtained in step S23.
The EV value is calculated by the apex operation from the sum of (step S27).

Subsequently, the CPU 10 lowers the EV value by 1 EV in step S29 when the light source detection flag is "1" in order to obtain a good balance between the constant light that strikes the subject at the time of detecting the light source and the strobe light. After step S30
When it is "0", the process directly proceeds to step S30 (steps S28 and S29).

In this step S29, step S27
EV value obtained in step 1, that is, the sum of photometric value and film sensitivity
By adding EV, the exposure of the subject due to the ambient light is intentionally reduced by 1 EV from the proper exposure. Making it 1EV under means that the amount of light hitting the film is halved.
Means to Then, if the subject is under 1 EV, a process of compensating by stroboscopic light emission is performed in steps S43 and S44 described later.

Next, the CPU 10 changes the EV value to the AV value,
The TV value is calculated by the program diagram as shown in FIG. 8 (step S30), and then the TV value and the shake TV
The value is compared (step S31). Where camera shake T
The V value is a TV value that can cause camera shake, and it is generally unlikely that a camera shake will occur if the shutter speed is faster than the shutter speed (SS), which is the reciprocal of the focal length. It is being appreciated. For example,
When the focal length (hereinafter abbreviated as f) is 30 mm, the camera shake SS is 1/30, the camera shake TV value is 5, and f = 50 m
When m, the camera shake SS is 1/60, the camera shake TV value is 6, and when f = 100 mm, the camera shake SS is 1/12.
The hand shake TV value is 7.

If the TV value is smaller than the shake TV value (TVo), the process proceeds to step S32, the strobe light emission request flag is set to "1" (step S32), and the TV is set.
The shake TV value (TVo) is stored in the value (step S3
3) and shifts to step S34. On the other hand, when the TV value is larger than the shake TV value (TVo), the process directly proceeds to step S34.

Next, the flash emission request flag is "0".
If it is (step S34), the process directly returns to the main sequence, and if it is "1", step S35.
The process shifts to the subsequent processing, and the AV, TV and GV values are recalculated.

That is, the aperture value is AV0 (open AV value)
Is stored (step S35), and the TV value is calculated from the difference between EV and AV (step S36). And as a result,
It is determined whether the TV value is larger than the strobe tuning second (shutter fully open second) (step S37). In this determination, if the TV value is larger than the strobe tuning second (shutter fully open second), the process proceeds to step S42, and if it is smaller, the TV value TVX at the strobe tuning second is stored in the TV value (step S38). ), And the AV value is calculated again from the difference between EV and this TV (step S39).

Next, the AV value is the maximum AV value AVmax (=
9) It is judged whether it is larger than (minimum aperture FNo. 22) (step S40), and if it is smaller, the process proceeds to step S42, and if it is larger, the maximum AV value AVmax is stored in the AV value (step S41), and step S42. Move to.
Then, the GV value indicating the flash emission amount is obtained by flashmatic calculation (GV = AV + DV-SV) (step S42).

Next, when the light source detection flag is "0", the process proceeds to step S45, and when it is "1", the step S45.
In step S44, the flash light emission amount is calculated to be reduced by 1 EV, and then the process proceeds to step S45. As a result, the ratio of the stationary light to the strobe light becomes 1: 1 (step S4).
4).

In step S44, when the artificial light source is detected as described in step S29, the exposure of the subject by the ambient light is set to 1 EV under (the light amount is 1/2), so that the insufficient light amount is detected. Computed to compensate with strobe light.

The GV value (strobe light emission amount) obtained by the flashmatic calculation in step S42 is a calculation in which the subject becomes appropriate when the strobe light is emitted in the dark. On the other hand, when the artificial light source is detected, the subject is given 1/2 of the amount of exposure due to the ambient light, and therefore the strobe light amount of 1/2 is sufficient. To reduce the strobe light to 1/2, subtract 1 GV from the GV value.

Subsequently, the CPU 10 determines whether the GV value is larger than the maximum light emission amount GVmax (step S45).
If the GV value is smaller than the maximum light emission amount GVmax, the process directly returns to the main sequence, and if it is larger, the process proceeds to step S46, and if the light source detection flag is "0", the process proceeds to step S49 to detect the light source. If the flag is "1", the GV value of the calculation result and the maximum light emission amount (G
It is determined whether the difference of Vmax) is 1 or more (step S4).
7).

When the ratio is 1 or more, the ratio of the stationary light to the strobe light is not 2: 1 or more, and the strobe light irradiated to the subject is insufficient, so that the photograph may have a color cast by the artificial light source. LED in viewfinder because it is predicted
Is displayed to give a warning to the user that a color cast due to the artificial light source will occur (step S48).
Next, since the GV value exceeds the maximum light emission amount, the maximum GV value (GVmax) is stored in the GV value (step S4).
9) and returns (step S50).

Here, in FIG. 10, the AV value, TV value,
A table for each relationship among the SV value, DV value, GV value and aperture FNo, shutter speed, film sensitivity, subject distance, strobe guide number will be shown and described.

The ratio of the amount of ambient light to the amount of strobe light is shown as follows. Light intensity ratio = strobe light / ambient light When an artificial light source is detected, the amount of strobe light is suppressed so that the stationary light and the strobe light have a 1: 1 ratio, and thus the energy consumption is reduced.

Furthermore, if the ratio of the constant light to the strobe light does not exceed 2: 1 (light quantity ratio 0.5) even when the strobe is fully emitted, such as a distant subject, the color cast of the artificial light source is not the strobe light. Since it cannot be canceled, a warning signal can be generated to prevent the failure to take a photograph with color cast.

In the present embodiment, the limit of the ratio of the amount of ambient light that can cancel the color cast and the amount of strobe light is set to 0.5, but even if the distance to the subject is long under an artificial light source and the strobe emits a full flash, the flash From the correctness of matic calculation 1.5
When the EV becomes under, the ambient light is set to be 0.5 EV under, so that an exposure close to a proper exposure can be obtained by both light amounts.

The peripheral light quantity at this time is 2 ^−0.5 = 0.707,
The strobe light amount is 2 ^−1.5 = 0.353, and the light amount ratio is 0.353 ÷ 0.707 = 1/2. If the amount of strobe light is less than this, a warning is output because the light amount ratio is such that color cast cannot be canceled. When changing the ratio of the stationary light and the strobe light when the artificial light source is detected, refer to FIG.
The constants to be subtracted from EV and GV in steps S29 and S44 are changed.

For example, EV = -0.5, GV = -1.5
Then, log ₂ ( ^2-0.5 + ^2-1.5 ) = 0.08. The amount of light given to the subject is 0.08EV value over the proper value when the constant light and the strobe light are combined, but the light amount ratio of the constant light and the strobe light is 0.5, and the color cast by the constant light is canceled by the strobe light. be able to.

Next, referring to the flowchart of FIG. 6, the subroutine "photometry" executed in step S21 is executed.
The sequence will be described. When entering this subroutine, the CPU 10 sets the output signal of the port VSFT to the low level "L" to turn off the transistor 24 (step 51). Then, it communicates with the IFIC 11 to output the photometric signal of the central pattern (step S52),
Wait for about 3 msec for the photometric output to stabilize (step S53), then 4.58 to remove commercial frequency noise.
Start the msec timer (step S5)
4). Subsequently, the CPU 10 receives the photometric signal output from the IFIC 11 at the port AD1 and performs A / D conversion (step S55). In this way, the process waits until the overflow of the 4.58 msec timer set in step S54 is detected, and when it overflows (step S5
6), A / D conversion is performed similarly to step S55 (step S57). Then, the A / D converted values are averaged and stored in the memory as the data of the central luminance (step S58).

Subsequently, the CPU 10 communicates with the IFIC 11 to output a photometric signal of the peripheral pattern (step S59), waits for about 3 msec during which the photometric output stabilizes (step S60), and removes commercial frequency noise. Therefore, a 4.58 msec timer is started (step S61). Subsequently, the CPU 10 uses the IFIC1
Receives the photometric signal output from port 1 at port AD1 and A /
D conversion is performed (step S62). Thus, step S6
It waits until the overflow of the timer of 4.58 msec set in 1 is detected, and when it overflows (step S63), A / D conversion is performed similarly to step S62 (step S64).

In this way, the A / D conversion values obtained in steps S62 and S64 are averaged and stored in the memory as data of the peripheral brightness (step S65), and the process returns to the main routine (step S66).

Next, the subroutine "light source detection" executed in step S22 will be described with reference to the flowchart of FIG. When you enter this subroutine, CP
A high level "H" signal is output to the port VSFT of U10 (step S71). Then, the transistor 24 is turned on, and as a result, the voltage VREF output from the IFIC 11 is divided by the resistors 20 and 21 to generate the voltage VREF ′.
Is input to the port VAD of the CPU 10.

Subsequently, the CPU 10 sets "0" in the area DTMAX for storing the maximum value as the initial setting of the memory,
"255" is stored in the area DYMIN for storing the minimum value (step S72), the channel for A / D conversion is set to the port AD2 (step S73), and IFIC1 is set.
Communication is performed so as to cause 1 to output the photometric signal of the peripheral pattern (step S74).

Subsequently, the photometric stabilization time is waited for 3 ms (step S75), a timer for measuring 10 msec is started (step S76), and A / D conversion is started (step S77). Subsequently, when the CPU 10 detects the completion of the A / D conversion (step S78), the A / D after the conversion is completed.
It is determined whether the value is larger than DTMAX (step S
79) If it is smaller, the process proceeds to step S81, and if it is larger, the A / D value is stored in DTMAX, and then the process proceeds to step S81 (step S80).

Next, the CPU 10 determines that the AD value is DTMIN.
It is determined whether or not it is smaller (step S81). If it is smaller, the process proceeds to step S83, and if it is larger, D
The A / D value is stored in TMIN (step S82), and the process proceeds to step S83.

Thus, steps S77 to S82 are repeated until the overflow of the timer of 10 msec set in step S76 is detected, and when detected (step S83), the timer is stopped (step S8).
4), the difference between DTMAX and DTMIN is obtained and stored in ΔDT (step S85).

Subsequently, the CPU 10 clears the light source detection flag to "0" (step S86) and determines whether ΔDT is 6 or more (step S87). And ΔDT
Is 6 or more, the light source detection flag is set to "1" in step S88, and then the process returns to the main sequence (step 89).

Next, the photometric calculation of this embodiment will be described in detail with reference to FIG. Now, the central weighted average photometric value BV =
6, open AV value AV0 = 5, film sensitivity ISO100
SV = 5, maximum light emission GVMAX = 8, subject distance 4
Assuming that DV = 4 from m and TVX = 8 at strobe tuning second, the EV value is EV = BV + SV = 6 + 5 = 11. When the light source detection flag is "1", 1 is added to the EV value as described above, so that EV = EV + 1 = 11 + 1 = 12. When the AV value and the TV value are obtained from the EV value = 12 using the program diagram of FIG. 8, AV = 5 and TV = 7. Here, strobe tuning second is 1/250, TV
When X = 8 and the shake TV value is 5, the upper and lower limiters are not affected, so the GV value is GV = AV + DV = 5 + 4 = 9. However, when the light source detection flag is "1",
Since "1" is subtracted from the GV value as described above, GV = GV-1 = 9-1 = 8. Here, there is no problem if GVMAX = 8. However, for example, when GVMAX = 6, GV-GVMAX = 8-6 = 2. Since this is one or more, the warning display is performed as described above.

Summarizing the results, AV = 5, TV = 7,
Strobe light is emitted at GV = 8 to perform exposure. As a result of this exposure, the normal light is one step below the subject and the strobe light is one step below the proper light, and the respective balance is 1: 1. When both are added, the subject is properly exposed.

Log ₂ (2 ⁻¹ +2 ⁻¹ ) = 0 ... Proper log ₂ (2 ⁻¹ +2 ⁻² ) = − 0.42… Under As described above, the strobe light is under two or more steps below the proper range. If the warning is not displayed, the balance of the strobe light of two steps under is at least 2: 1 for the subject when the warning is not issued, and the subject when both are added is 0. It is 42 steps under.

Next, FIG. 9 shows a graph in which a stroboscopic light is emitted under an artificial light source lamp, and a color cast on a subject of the artificial light source at the time of photographing is evaluated sensitively. Artificial light sources are fluorescent lamps (daylight), fluorescent lamps (white), flat lamps, and incandescent lamps.

The horizontal axis of the figure represents the light amount ratio between the artificial light source and the strobe light (strobe light amount / artificial light source light amount). When the main subject is corrected and exposed with only the artificial light source, it is set to “0”. When the main subject is properly exposed only with the strobe light, it is set to infinity. Is set to 1.0 when the flash subject is applied to the main subject (the main subject is 1 EV over the proper exposure). The light quantity ratio is 0.5, 0.25, 0.12 as the artificial light source light quantity is made constant from the light quantity ratio 1 and the strobe light quantity is halved in order.
5, the light amount ratio becomes 2.0, 4.0, and 8.0 as the light amount ratio becomes 1 and the strobe light amount becomes constant and the artificial light source light amount is gradually halved.

On the vertical axis of the figure, the classification for the sensitive judgment is shown.
Area 1 has no color cast, Area 2 has a slight color cast when you look closely, Area 3 has a slight color cast, Area 4 has a color cast, and it is shown in four areas. There is. From this graph,
If a border line is drawn between areas 3 and 4, the fogging of the artificial light source can be reduced if the light intensity ratio is 0.5 or more, and if the areas 2 and 3 are photographs with less color cast, the light intensity ratio is approximately 1. It turns out that it will be possible.

Next, a second embodiment of the present invention will be described. In the above-described first embodiment, when the light quantity ratio of the ambient light and the strobe light is not 2: 1, it is judged that the color cast of the artificial light source cannot be canceled, but a warning is issued, but the strobe light is insufficient. If not, it is also possible to reduce the amount of light in the surrounding area in accordance with the strobe light and expose the object and the background in balance. However, in this case, since the photograph is underexposed as a whole, it is necessary to correct it at the time of printing. Also, the exposure range (latitude) in which colors can be reproduced by making corrections during printing is different between negative film and reversal film. Generally, negative film is 5 to 7 EV and reversal film is 1 to 2 EV.
It is said to be EV. Therefore, the range allowed from proper exposure to underexposure is half that 3EV or 0.
It is set to 75 EV and set to the underexposure limit value. If the limit value is exceeded and underexposure occurs, a warning is issued.

FIG. 11 is a block diagram of a strobe camera according to the second embodiment. Since reference numerals 31 to 37 in FIG. 11 correspond to the reference numerals 1 to 7 in FIG. 1 of the first embodiment, the description thereof will be omitted here. The film information detection unit 38 reads the film sensitivity, latitude, number of shots, film type, etc. recorded in the film cartridge or cartridge, and sends the information to the arithmetic control unit 34.

FIG. 12 shows a flowchart of the processing of the second embodiment which replaces the warning display portion of step S48 of FIG. 5 of the first embodiment. Step S4 of FIG.
2, the difference between the GV value obtained in S44 and the maximum value GVMAX of the GV value capable of emitting light is obtained and set as GVA. GVA indicates the insufficient GV value at the time of full light emission (step S
91). Then, GVA is added to the TV value to obtain TVA. This TVA is a TV value for reducing the amount of ambient light in accordance with the insufficient amount GV of flash light emission. Therefore, the ambient light can be reduced by adding the shortage of the strobe to accelerate the shutter speed. Here, if the aperture value is changed to reduce the ambient light, the strobe light is also affected, so the aperture value is not changed (step S92).

The TVA thus obtained is compared with the time when the shutter is fully opened for stroboscopic light emission, and if there is a difference of 1 EV or more, it is determined that the influence of color cast cannot be canceled even if the ambient light is under ( In step S93), a warning is given (step S94).

Next, since the latitude is different between negative and reversal, the allowable range for changing the overall exposure from appropriate to under is switched (step S95). That is, when negative, the limiter value is set to 3 EV (step S9).
6) In the case of reversal, the process proceeds to step S97 and the limiter value is set to 0.75 EV (step S97).
After this setting, the GVA calculated in step S91 is compared with the limiter value, and when GVA exceeds the limiter value, the exposure is adjusted from the proper exposure to under, so that the color reproducibility at printing exceeds the latitude of the film. If it is determined that there is not (step S98), a warning is displayed (step S9).
9).

Then, the T calculated in step S92 is calculated.
It is determined whether or not VA has exceeded the fully open second required for strobe emission (step S100). If it has exceeded, the full open second is set, so TVX is assigned to TVA (step S101) and TVA is assigned to TV. Yes (step S1
02).

As described above, according to the present invention, when the strobe light is insufficient while maintaining the light amount balance between the ambient light and the strobe light at a ratio capable of canceling the color cast, the entire exposure is changed to the color at the time of printing. In order to improve the exposure balance between the subject and the background, the exposure is performed by density correction at the time of printing so that the exposure is balanced in a reproducible range.

According to the above embodiment of the present invention, the following constitution can be obtained. (1) Artificial light source detection means for detecting the field brightness and detecting the presence or absence of the artificial light source based on the pulsating flow from the artificial light source; and, when it is determined that the artificial light source is present, A light quantity ratio calculating means for calculating the light quantity ratio between the strobe and the ambient light including the light of the artificial light source so as not to adversely affect the exposure state of the film by correcting the influence of the color temperature, and the output of the light quantity ratio calculating means. And a strobe light emission amount control means for controlling the light emission amount of the strobe based on the above. (2) The artificial light source detection means is set so that the field brightness value falls within a predetermined reference voltage value when detecting the field brightness, and the artificial light source of the artificial light source is detected based on the pulsating current. The camera with a strobe according to (1) above, wherein when detecting the presence or absence, the reference voltage value is set to be smaller than the predetermined reference voltage value. (3) Artificial light source detection means for detecting the presence or absence of the artificial light source based on the pulsating flow from the artificial light source, and the existence of the artificial light source so that the color temperature specific to the artificial light source does not adversely affect the exposed state of the film. A light quantity ratio calculating means for calculating a light quantity ratio of the strobe and ambient light including light of the artificial light source to a predetermined value, and an exposure amount on the film surface based on a calculation result of the light quantity ratio calculating means. And an exposure control unit that corrects the strobe light emission amount to the underside of a normal value, and a strobe light emission amount control unit that controls the strobe light emission amount based on the output of the exposure control unit. Characteristic camera with strobe. (4) The exposure control means determines an apparent exposure value so that it becomes appropriate when a strobe is emitted in the dark, and the apparent exposure value is calculated from the aperture value and the peripheral light amount calculated based on the apparent exposure value. The strobe-equipped camera described in (3) above, wherein the strobe light emission amount is calculated. (5) Film information detecting means for detecting at least latitude information of the loaded film, and artificial light source detecting means for detecting the field brightness and the presence or absence of the artificial light source based on the pulsating flow from the artificial light source, The light amount ratio of the strobe light to the field luminance value and the ambient light including the light of the artificial light source so that the color temperature specific to the artificial light source due to the presence of the artificial light source does not adversely affect the exposed state of the film. Based on the calculation result of the light amount ratio calculating means and the light amount ratio calculating means, the exposure amount for correcting the exposure amount on the film surface and the stroboscopic light emission amount to the under side of the normal value, respectively. The control unit and the detected latitude when the strobe light amount corrected by the exposure control unit cannot be satisfied even if the strobe emits full light. Flash camera with in the range of characterized by comprising an exposure changing means for changing the exposure amount on the film surface. (6) When the exposure amount on the film surface changed by the exposure changing unit is out of the latitude range, a warning unit is further provided to warn that the exposure is underexposure. The camera with a flash described in).

[0071]

According to the present invention, even when the flash is bright and does not require stroboscopic light emission, the stroboscopic energy consumption is reduced and the failure to take a photograph with a color cast due to the artificial light source is prevented. It is possible to provide an attached camera.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a camera with a strobe according to the present invention.

FIG. 2 is a diagram showing a configuration of a circuit that detects a pulsation of an artificial light source using a photometric circuit.

[FIG. 3] Voltage VREF and divided voltage VREF ′, port A
It is a figure which shows the relationship of the signal of D1 and AD2.

FIG. 4 is a flowchart showing a main sequence of a camera with a strobe.

5 is a flow chart for explaining a process of a subroutine "photometric calculation" executed in step 8 of FIG. 4. FIG.

FIG. 6 is a flowchart showing a sequence of a subroutine “photometry” executed in step S21 of FIG.

FIG. 7 is a flowchart showing a sequence of a subroutine “light source detection” executed in step S22 of FIG.

FIG. 8 is a diagram for specifically explaining the photometric calculation of the embodiment.

FIG. 9 is a diagram showing a graph in which the color cast on the subject of the artificial light source is sensitively evaluated when a strobe is emitted under the artificial light source lamp and a picture is taken.

FIG. 10 is a diagram showing a table for each relationship among an AV value, a TV value, an SV value, a DV value, a GV value, an aperture FNo, a shutter speed, a film sensitivity, a subject distance, and a flash guide number.

FIG. 11 is a configuration diagram of a camera with a strobe according to a second embodiment.

FIG. 12 is a flowchart of the process of the second embodiment that replaces the warning display portion of step S48 of FIG. 5 of the first embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Artificial light source detection part, 2 ... Photometry part, 3 ... Distance measurement part, 4 ... Calculation control part, 5 ... Strobe light emission part, 6 ... Exposure part, 7 ... Focusing part.

Claims (3)

[Claims] 1. An artificial light source detection means for detecting the presence or absence of an artificial light source based on a pulsating flow from the artificial light source, and a color unique to the artificial light source when the artificial light source detection means detects that there is an artificial light source. In order to prevent the temperature from adversely affecting the exposed state of the film, a light amount ratio calculating means for calculating the light amount ratio between the strobe light amount and the ambient light including the light of the artificial light source, and based on the output of the light amount ratio calculating means, A strobe-equipped camera, comprising: a strobe light-emission amount control means for controlling a strobe light-emission amount. 2. An artificial light source detecting means for detecting the presence or absence of an artificial light source based on a pulsating flow from the artificial light source, and a color unique to the artificial light source when the artificial light source detecting means detects that there is an artificial light source. In order to prevent the temperature from adversely affecting the exposed state of the film, a light amount ratio calculating means for calculating the light amount ratio between the strobe light amount and the ambient light including the light of the artificial light source, and based on the output of the light amount ratio calculating means, The flash emission amount control means for controlling the flash emission amount, and the color fog warning means for warning that the exposure state of the film is adversely affected when the output of the light amount ratio calculation means is not within the predetermined range are provided. This is a camera with a strobe. 3. The artificial light source detection means outputs a field brightness detection means for detecting a brightness of a field due to at least one of ambient light and artificial light, and outputs of the field brightness detection means. The camera with a strobe according to claim 1 or 2, further comprising pulsating flow presence / absence detecting means for detecting the presence / absence of pulsating flow from the artificial light source.