JP3193489B2 - Strobe system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless slave strobe system which is provided at a position distant from a camera and emits an auxiliary light whose light emission amount is controlled.

[0002]

2. Description of the Related Art In general, there is a wireless slave strobe system which emits auxiliary light at the time of photographing by a strobe device which is arranged at a position remote from a camera and responds to a light emission start signal of a built-in strobe device of the camera.

For example, as a first example, Japanese Patent Application Laid-Open No. Sho 64-17
In the strobe system proposed in Japanese Patent Publication No. 033, a slave strobe disposed outside intermittently repeats minute light emission in response to a light emission start signal of a built-in strobe device of the camera, and the camera integrates reflected light of a subject. When it becomes appropriate, the built-in strobe emits light again, and the fact that the strobe becomes appropriate is transmitted to the slave strobe, and the light emission ends.

As a second example, Japanese Patent Application Laid-Open No. Hei 3-1006
In the strobe system proposed in Japanese Patent Publication No. 33, data communication between a camera and a wireless slave strobe is
Camera side transmission means-Built-in flash or AF auxiliary light,
A camera-side receiving means-AF light receiving element, a strobe-side transmitting means-strobe, a strobe-side receiving means-a dedicated light receiving element have been used.

[0005] Further, the light emission amount control of the slave strobe is
Light emission was started and stopped in response to the built-in flash of the camera.

[0006]

However, the above-mentioned first method
The example strobe system has the following problems.

First, due to intermittent light emission, the entire light emission time is as long as 1/60 second, and camera shake may occur. Also,
Since intermittent light emission is performed at the time of short-range shooting, an overexposure may occur due to an error in the amount of light emission at one time.

On the other hand, in the second strobe system, first, since the emission of the slave strobe is linked with the built-in strobe, it is impossible to emit only the slave strobe. Therefore, even if the slave strobe is moved away from the camera to take a so-called red-eye-free photograph, the built-in strobe emits light in conjunction with it, and the occurrence of red-eye cannot be completely suppressed.

Furthermore, since the strobe light is emitted when data communication is performed between the camera and the slave strobe, the photographer or the subject is determined to have finished photographing.

Accordingly, the present invention provides a strobe system in which a camera calculates a suitable light emission amount for main light emission from a subject reflected light emitted by a slave strobe, transmits the calculated light amount to the slave strobe, and selectively performs proper light emission with an appropriate amount of light. The purpose is to provide.

[0011]

In order to achieve the above object, the present invention provides a strobe system comprising a camera and a strobe device which can be arranged at a position spatially separated from the camera. A receiving unit for receiving data from the camera; and a pre-emission unit for performing pre-emission of a predetermined amount of light on the subject, wherein the camera transmits data to the strobe device. Transmitting means, prior to shooting, pre-flash command means for executing the pre-flash to the strobe device via the transmitting means and the receiving means, and receives reflected light from the subject at the time of the pre-flash, A light emission amount calculating means for calculating a main light emission amount required at the time of photographing based on the received light amount; A flash communication device for transmitting light emission timing to the strobe device via a stage before photographing; and a flash timing communication device for transmitting flash timing data relating to a main flash timing to the flash device in connection with a photographing operation; The apparatus provides a strobe system that controls light emission based on the main light emission amount data transmitted from the camera.

[0012]

In the strobe system having the above-described configuration, the slave strobe device emits a predetermined amount of infrared light (pre-emission) before the main light emission, receives the reflected light of the subject on the camera side, and is required for the main light emission. Is calculated. The value is transmitted to the slave strobe device by blinking the infrared light emitting element of the camera, and the main light emission appropriate for photographing is performed. In this strobe system, the built-in strobe and the slave strobe device are individually controlled, and a desired built-in strobe and slave strobe device are selected to emit light.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows the configuration of a strobe system as a first embodiment according to the present invention, and will be described.

First, FIG. 1A shows a block configuration of a camera and will be described. In this camera, each component is driven and controlled by a control circuit 1 that controls a sequence calculation function. The control circuit 1 includes a transmission unit including a transmission circuit 2 that generates a transmission signal to a slave strobe device described later and an infrared light emitting diode 3 that photoelectrically converts the transmission signal and emits the transmission signal as infrared light. Photodiode 5 that photoelectrically converts infrared light from a slave strobe device
And a receiving unit including a receiving circuit 4 that receives the signal converted by the photodiode 5.

The charging circuit 6 stores high-pressure energy in a main capacitor (not shown) in order to cause the strobe light emitting section 9 built in the camera to emit light.

The light emission start circuit 7 starts the light emission of the xenon tube of the strobe light emitting section 9 composed of a reflection lamp and a xenon tube according to the control signal of the control circuit 1. Light emission of the xenon tube is stopped halfway by a control signal of the control circuit 1.

The distance measuring circuit (AF) 10 has a three-point AF.
A distance measuring light is projected from an infrared light emitting diode (IRED) 11 for a subject to a light position detecting element (PS) for a three-point AF.
D) The reflected light reflected by the object is received at 12, and the distance to the object is measured. Similarly, the photometry circuit 13 performs photometry with the attached photodiode 14 having sensitivity in the visible light range, and based on the photometry result, an exposure control circuit 15 for driving a shutter (not shown).
Controls the exposure.

The lens drive circuit 16 drives the lens to an appropriate position based on the distance measurement result of the distance measurement circuit 10. The film feeding circuit 17 is driven under the control of the control circuit 1 for winding and rewinding after the end of exposure. These distance measurement, photometry, exposure, and the like are performed in two stages (1R, 2R).
The operation is carried out by pressing the release button 18 composed of the following switches.

Next, FIG. 1B shows the configuration of a slave strobe device and will be described.

The components of the slave strobe device are as follows:
Sequence control is performed by the control circuit 21. Transmission circuit 2
2 and the infrared light emitting diode 23, the receiving circuit 24 and the photodiode 25 are transmitting and receiving circuits for exchanging information between the slave strobe device and the camera.

Similarly, a charging circuit 26, a light emission starting circuit 27,
The light emission stop circuit 28 and the flash light emitting unit 29 perform the same operation as the above-described camera member.

The light emitting circuit 30 controls the pre-emission performed before the main light emission by the infrared light emitting diode 31 having a light distribution characteristic substantially equal to the light distribution angle of the strobe light emitting section 29 to emit light. Also, a channel CH to be described later
A channel setting switch 32 for setting 1 and CH2 is provided.

Next, FIG. 2A shows a specific configuration of the receiving circuits 4 and 24 of the same configuration shown in FIG.
Shows and describes the output waveform of the member.

First, a communication signal having a frequency around 30 KHz as a carrier is received by the photodiode 33 (25), and is amplified by the preamplifier 34.

Next, the signal is passed through a band-pass filter 35 to remove noise having other frequency components, and a carrier is removed by a peak detection and integration circuit 36. Further, by passing through a waveform shaping circuit 37, the signal is converted into a complete digital signal.

Next, FIG. 3 shows an example of code data transmitted and received in this embodiment. For example, the code "101011
01 ", the synchronous clock (a)
The light of the code of the transmission pattern (c) is put on the carrier wave to emit light. Then, the receiving circuit as shown in FIG. 2 can shape the reception pattern (d) as a shaped waveform (e) and code it.

FIG. 4 is a flow chart showing the operation of the flash system according to the first embodiment of the present invention. Here, this strobe system is an example in which one slave strobe device is driven and the built-in strobe of the camera does not emit light.

First, it is determined whether or not the slave strobe mode of the camera is set, and if not set (N
O), a normal mode process is performed (step S3),
If the setting can be confirmed (YES), the camera side transmits the transmission circuit 2
Then, an ON signal for turning on the power is transmitted from the infrared light emitting diode 3 to the slave strobe device (step S2).

Thereafter, data communication for necessary information exchange is performed between the camera and the slave strobe device (step S4), and charging of the slave strobe device is started (step S5).

Next, when the release button 18 of the camera is half-pressed (1R is turned on) (step S6), a charge completion display (step S7), a distance measurement operation (step S8), and a photometry operation (step S9) are performed. Done.

From these measurement results, it is determined whether or not the brightness of the slave strobe device is necessary for photographing at the time of photographing (step S10). If it is determined that the luminance does not require light emission (NO), a normal mode process is performed (step S3), and if it is determined that the luminance is low requiring light emission (YE).
S), the camera instructs the slave strobe device to perform pre-flash (step S11).

That is, the infrared light emitting diode 31 performs a predetermined number of pre-emissions, the reflected light of the subject is received by the light receiving element (PSD) 12 of the distance measuring circuit 11 of the camera, and the result is integrated to perform the main emission. The control circuit 1 calculates the required light emission amount (step S12) and transmits the information to the slave strobe device together with the light emission timing information (step S1).
3).

Next, after the release button 18 of the camera is completely depressed (2R is turned on) and the lens is extended (step S14), a flash start signal is transmitted to the strobe device (step S16), and the shutter control is started. It is executed (Step S17).

Further, the strobe device waits during the light emission timing information to open the shutter,
Therefore, a predetermined amount of light emission is performed based on the light emission amount data. On the camera side, the AF light receiving element (PS
D) The integration of the strobe light emission is confirmed by integrating at 12 and confirming that a predetermined voltage has been reached (step S1).
8), and display it (step S19). Thereafter, the film is fed (step S20).

Next, the detailed operation of the flash system of the first embodiment will be described with reference to the flowcharts of FIGS. 5 to 8 and the timing charts of FIGS.

In the timing chart of FIG. 5, when the camera is set to the slave mode (step S2).
1), the transmission circuit 2 transmits a single pulse to the slave strobe device (step S22). Normally, the slave strobe device is in a standby mode in which only the light receiving element 25 is turned on. However, receiving this pulse light turns on the receiving circuit 24 (step S23).

Next, the camera waits for a predetermined time sufficient for the receiving circuit 24 of the slave strobe device to be turned on (step S24), and then outputs a CH1 POWER ON signal based on a communication format shown in FIG. Is transmitted (step S25). This signal is
When it is "100", CH1 is specified, and the subsequent 5
The bit is “10001” indicating a POWER ON instruction. However, after the POWER ON instruction, 8bi
The data code of t is not attached.

The receiving circuit 24 of the strobe device is connected to CH1
When the arrival of the POWER ON signal is recognized (step S26), the signal is transmitted to the control circuit 21, the power of the entire flash device is turned on, and the operation mode is entered (step S27).

The control circuit 21 transmits the CH1 POWER ON signal as a confirmation signal to the camera using the same code as the reception code by the transmission circuit 22 (step S28).

Then, the confirmation signal is received by the receiving circuit 4 of the camera, and it is determined that the communication with the slave strobe device has been established (step S29). If the determination is not made (NO), the normal mode processing is performed (step S30). If the determination is made (YES), the control circuit 1 sets the flag of CH1 (step S31).
Next, the control circuit 1 communicates a code n _VP (apex value) indicating the number of times of light emission during the pre-light emission from the transmission circuit 2 to the light emission circuit 30 (step S32).

For example,

(Equation 1) , The upper 3 bits represent the communication of “CH1”, the next 5 bits represent the communication of “pre-lighting frequency n _VP ”, and the next 8 bits represent “data of the number of light projections”.

In the flash device, when the receiving circuit 24 receives the code _nVP (step S33), the control circuit 21 stores the data of the number of pre-emissions in a predetermined RAM. FIG. 14 shows an example of the format of communication data used in this embodiment. Although not shown in the flowcharts of FIGS. 5 to 8, in all data communications,
It is also possible to transmit the same data as the data received for confirmation to the other party again.

[0044] Next strobe device side transmits its guide number G _VP per pre projection once the camera by the transmitting circuit 22 (step S34, S35). For example

(Equation 2) _GVP = 0.

The above code n _VP and guide number G
_VP is a so-called apex value defined by logarithm to base 2 of the pre-light projection count n _P and the pre-guide number G _P that follows. G _VP = log ₂ G in the term of equation (1) described later
_P ² (pre-guide number per light emission), n _VP = 1
og ₂ n _P (the number of pre-emissions). From equation (2) described later, n _VP = 3 indicates the number of pre-emissions n _P 2 ³ = 8, and G _VP = 0 indicates the number of pre-emissions. Guide number _GP = 2 ⁰ =
Represents 1. Hereinafter, all subscripts of "V" represent apex values.

The next communication toward the apex value G _Vmax of apex value G _Vmax and the minimum guide number G _min maximum guide number G _max at the light emission having the strobe device itself to the camera (step S36 to S39). When this communication is completed, the control circuit 21 sends an ON signal to the charging circuit 26 (step S40), and starts charging the main capacitor.

When the charging reaches a predetermined voltage (step S41), the charging circuit is turned off (step S42), and the following charging completion signal code is transmitted (step S43).

[0048]

(Equation 3) When the camera receives this signal (step S44),
The charge completion flag is set, and the process waits for the release button 18 to be pressed (step S45).

Next, the calculation of the light emission timing and the light emission time according to this embodiment will be described with reference to the flowcharts of FIGS. Here, the predetermined times t _{1 to} t ₆ correspond to those in FIG.
These are the times shown in the timing chart of (far distance) and the timing chart of FIG. 10 (short distance), respectively.

First, the release button 18 is half-pressed (1RO).
N) (step S51), and it is determined whether or not the charging completion flag is set by the control circuit 1 (step S51).
52), if the charge completion flag is set (Y
ES), a charge completion display is performed (step S53).

Next, the AF operation is started. First, the left (L) center (C) right (R) IRED 11 and the corresponding PSD 12 are selected by the distance measuring circuit 10, and the IRED is projected a predetermined number of times to reflect light from the object. Then, the distance to the subject is obtained by integrating the PSD photocurrent (step S54).

Since the position where the reflected light enters differs depending on this distance, the output currents i ₁ and i _{2 of the} PSD are:

(Equation 4) And the ratio calculation output for finding the distance,

(Equation 5) Has a light quantity integration output for obtaining the distance.

The data of the closest channel (of LCR) among the three points measured as described above is adopted (step S55). A detailed description of AF will be made separately.

Next, the control circuit 1 turns on the photometric circuit 13 to measure the luminance of the subject (step S56). As a result of the photometry, if it is determined that the strobe device requires a low luminance at the time of photographing (step S57), the control circuit 1 performs a pre-light emitting operation and enters an operation for obtaining a required light amount of the slave strobe device. First, the channel (L
The light receiving circuit of (CR) is turned on (step S58). However, at the time of photographing, if the luminance is unnecessary for the strobe device, normal mode processing is performed (step S59).

Next, a pre-lighting start signal is transmitted to the strobe device (step S60). After waiting for a certain period of time (step S61), the light amount integration circuit (i ₁ + i ₂ ) in the distance measuring circuit 10 is turned on for t ₁ (step S62,
S63), between t ₂ OFF (step S64, S65)
Is performed n _P times (step S66). The n
_P is the code n _VP (n _P = 2) previously communicated to the strobe device
_{Raised to the} power of n _VP ). Therefore, if n _VP = 3, n _P = 8
Times. After performing the eight integration operations, a second integration operation is performed to confirm the value (step S6).
7), calculate an integrated voltage v _out . As the reflected light from the subject increases, the current (i ₁ + i ₂ ) flowing through the PSD 12 increases, and the integrated voltage v _out increases.

[0056] The flash device receives the pre-light projection start signal (step S68), after a certain period of time so as to synchronize the camera side of the integration operation (step S69), the light projecting circuit 30 is t ₁ ON (Step S7)
0, S71), OFF during the t ₂ (step S72, S7
The operation of 3) is repeated n _P times (step S74). The t _1, t _2, n _P is the distance measuring circuit 10 of the camera t _1, t
₂ , Designed to be completely synchronized with n _P.

The light emission of the infrared light emitting diode 31 is as follows.
Due to the reflection cover (not shown), the light distribution characteristics are the same as those of the main light emitting unit 29.

Then, the integral voltage v _out is calculated by the double integration operation of step S67 (step S7).
5). The value of the calculated integrated voltage v _out is set to a predetermined value v ₁
(Step S76), and when the value of the integrated voltage v _out is larger than the predetermined value v ₁ (YES), since the strobe device is too close and the integration operation overflows, the light emission frequency n _VP is reduced. (Step S77), Step S60
And execute again. Further, the integrated voltage v _out is compared with a predetermined value v ₂ (v ₁ > v ₂ ) (step S7).
8) If the integrated voltage v _out is smaller than the predetermined value v _{2, an} accurate value cannot be obtained, so 1 is added to the number of times of light projection v _VP , and the process proceeds to step S60, and is executed again.

Then, the guide number (G) required for the main light emission can be obtained by the following equation.

[0060]

(Equation 6) Here, K: constant G _P: Pre floodlight once per guide number F _0: opening of the photographing lens F-number n _P: Pre projection number v _out: subject is determined by the pre-light projecting to n _P times Integral voltage depending on the amount of reflected light ISO: film sensitivity. The expression that the bottom of each 2 as _{follows, K V = log 2 K /} 3.1: constant ^{_{G VP = log 2 G P 2}} : 1 times the pre-guide number per projection A _Vo = log ₂ F _o ² : aperture value n _VP = log ₂ n _P : number of pre-emissions v _V = log ₂ v _out : integrated voltage _SV = log ₂ ISO / 3.1: film sensitivity

(Equation 7) Can be converted to

The control circuit 1 obtains the light quantity G _V required for the main light emission according to the equation (2) (step S80).

Then, the obtained light quantity G _V is compared with the maximum guide number G _Vmax transmitted from the strobe device (step S81), and if the light quantity G _V is larger than the maximum guide number G _Vmax in this comparison (NO) ), An underexposure occurs even if the light is emitted, so that a warning signal is generated (step S82). Further, by comparing the smallest guide number G _Vmin light quantity G _V and the strobe device is put out (step S
83) If the light amount G _V is larger than the minimum guide number G _Vmin (YES), that is, G _Vmin <G _V <G _Vmax ,
It is possible to set the proper exposure.

However, when the light amount G _V is smaller than the minimum guide number G
If it is smaller than _Vmin (NO), that is, G _V <G
_Vmin , light emission causes overexposure. Therefore, it is necessary to make the slave strobe device emit main light immediately before the aperture is fully opened.

If G _Vmin <G _V <G _Vmax , the exposure can be properly set, and the camera transmits the G _V code and its data to the flash device (step S84). A light emission timing code indicating how long after the light emission start signal to be sent when the light is actually emitted and the shutter fully opened and its data are also transmitted (step S85).

[0065] The flash device receives the light emission timing code and G _V code (step S86, S87),
Required emission from the value of G _V by the control circuit 21 (t ₃₎ determine the time (step S88). This may be obtained from a table of _GV value and light emission time or may be obtained by calculation.

When G _V <G _Vmin , the exposure becomes overexposed, so that the aperture is set to an apex value (G _Vmin −
G _V ) (steps S89 and S90), and transmits the emission timing code shifted by that amount (step S89).
91). When the apex value of the shutter fully open time is T _V0 as shown in FIG.

(Equation 8) Is required to be transmitted.

Next, the operation of the flash system of this embodiment will be described with reference to the flowchart of FIG. Here, the predetermined times t _{1 to} t ₆ are the times shown in the timing chart of FIG. 9 (far distance) and the timing chart of FIG. 10 (short distance), respectively. First, the camera's release button 1
It is determined whether or not 8 is completely pressed (2R is ON) (step S101), and if 2R is ON (YES),
Based on the distance measurement data, the lens drive circuit 16 extends a photographic lens (not shown) (step S102), and transmits a light emission start signal (step S103).

Thereafter, the shutter plunger is turned on (step S104), and a timer built in the camera is started (step S105).

After the timer starts, a predetermined time t
When _{the 4} has elapsed (step S106), a shutter (not shown) is fully open, in order to check the flash sync at that time, the light receiving circuit of the distance measuring circuit 10 of the channel which adopts (integrated circuit) to a predetermined time t ₅ (Steps S107, S108, S109).

Then, when a predetermined time t _{6 has} elapsed for the shutter, the integration circuit is turned off (step S).
110).

Upon receiving the light emission start signal (step S117), the flash device adjusts the light emission timing (step S118). This waits for the light emission timing data received earlier. In such an operation time, in the time chart of FIG.
₄ hours. After waiting completion, the control circuit 1 and to start emission of the flash device is turned ON the light emission start circuit 27 (step S119), at the same time the timer is started (step S120), after the lapse of the predetermined time t ₃ when it determined earlier (Step S121) The light emission stop circuit 28 is turned on to stop light emission (Step S122).

After the predetermined time t _{6 has} elapsed, the integrating circuit is turned off, and then the camera turns off the plunger (step S111), and the main object reflected light received by the distance measuring circuit 10 is reflected. For confirmation, a second integration operation is performed (step S112), and the output v _out is compared with a predetermined value v ₀ (step S113). The output v
_{If out} exceeds the predetermined value v ₀ (YES), the synchronization is confirmed and displayed (step S114), and the film feed circuit 17 winds the film by one frame (step S1).
15). Also if the output v _out is less than the predetermined value v ₀ (NO), the process ends without tuning confirmation.

FIG. 11 shows the configuration of the distance measuring circuit 10 and will be described.

As shown in FIG. 11, a conventional distance measuring device includes light projecting and receiving lenses 41 and 42 having two optical axes 41a and 42a separated by a fixed base length (S), and a light projecting IRED (near infrared ray). Light emitting diode) 43, PSD of length t for light reception
(Position detecting element) 44.

When the PSD 44 is arranged such that the end face of the PSD 44 is located at a position a distance a from the optical axis 42a of the light receiving lens 42, the object distance is D, and the focal length of the light receiving lens 42 is f _j . In the case, the subject 45
The center of gravity of the reflected spot 46 returns from the end face of the PSD 44 to the position of “(Sf _j / D) + a”. The P
Since the SD 44 generates a current output proportional to the position of the reflection spot 46, the side closer to the light projecting lens 41 of the PSD 44 is used as the first electrode (1ch), and the light projecting IRED is used.
One side of the output change current when 43 emits light is i ₁ ,
Assuming that the reflection side is i ₂ , the following equation (4) holds.

[0076]

(Equation 9) When the equation (4) is modified, the following equation (5) is obtained.

[0077]

(Equation 10) Therefore, from the currents i ₁ and i ₂ , i ₂ / (i ₁ + i ₂ )
Is calculated, the reciprocal 1 / D of the subject distance can be obtained based on the above equation (5).

FIG. 12 shows an auto focus operation integrated circuit (AFIC) 4 in the distance measuring circuit 10 shown in FIG.
7 shows the internal configuration of the apparatus. This AFIC 47
It comprises a ratio calculation circuit section 47A and a light quantity integration circuit section 47B.

First, the ratio calculation circuit unit 47A will be described. The output ends of the two PSDs 4, that is, PSD-L and PSD-R, are connected to 1ch and 2ch, respectively, and AFIC
47 is input. 1ch, 2ch of AFIC47
Input terminals i ₁ , i ₂ are connected to the inputs of the preamplifiers A 1, A 2 and the transistors Q 3, through which the steady photocurrent of the PSD 4 flows.
It is connected to the collector of Q4 and the bases of transistors Q1 and Q2 for amplifying the signal current (change) when the IRED 3 emits light.

Then, the signal current amplifying transistors Q1, Q
The emitter 2 is connected to the output terminals of the preamplifiers A1 and A2, and the collector is connected to logarithmic compression diodes D1 and D2.
The cathodes of these diodes D1 and D2 form feedback loops for steady-state light storage, so that feedback amplifiers A3 and A4
Has been entered on one side.

The other input terminals of the feedback amplifiers A3 and A4 are connected to the diodes D3 and D4 in order to make the same level as the bias point of the diodes D1 and D2.
Is connected. The output terminals of the feedback amplifiers A3 and A4 are connected to the stationary light level storage capacitors C1 and C2 and the bases of the transistors Q3 and Q4. The feedback amplifiers A3 and A4 can control the operation of the amplifier, that is, whether or not the feedback of the steady light storage is performed, by turning on / off the switches SW1 and SW2.

The cathodes of the diodes D1 and D2 are
It is connected to the bases of transistors Q5 and Q6 forming a differential circuit. The emitters of the transistors Q5 and Q6 are connected in the same manner, and are connected to GND via the constant current source _Io and the switch SW5. The transistor Q
The collector of transistor 6 is connected directly to _Vcc, and the collector of transistor Q5 is connected to _Vcc via an integrating capacitor C3. Further, the collector of the transistor Q5 includes a switch SW4 via the constant current source I _G, is connected to the power supply V _cc, and is connected to V _ref via a switch SW3. Furthermore, the collector of the transistor Q5 is also connected to the input terminal of the comparator COM1. The other input terminal of the comparator COM1 is V
_ref , and the output terminal is output to the outside of the AFIC 47 and is connected to an arithmetic unit (not shown).

Next, the configuration of the light quantity integration circuit section 47B will be described.

The COM terminals of PSD-L and PSD-R are
It is connected to the COM terminal of the AFIC 47 and is connected to the collector of the diode-connected transistor Q9 in the AFIC 47. This transistor Q9 is
7, and the collector of the transistor Q7 is connected to the collector of the steady-state light storage transistor Q8 via four serially-parallel-connected analog switches SW6 to SW9.

Then, the differential amplifier for stationary optical storage A5-2
The two input terminals are connected to _Vref via R1 and R2 having equal resistance values. An intermediate point on one side of the serial / parallel analog switch is input to one side of the amplifier A5. The output of the amplifier A5 is a stationary optical storage capacitor C
4 and the base of the transistor Q8. The other intermediate point of the serial / parallel analog switch is an integrating amplifier A6.
Input terminal, integrating capacitor C5, and switch SW
10 is connected. Switch SW10 is connected to the GND via the constant current source I _G. The other end of the integrating capacitor C5 is connected to the output of the integrating amplifier A6 and the input of the comparator COM2. The inputs on one side of the integrating amplifier A6 and the comparator COM2 are connected to _Vref .

Next, the ratio calculation operation and the light amount integration operation will be described with reference to the timing chart of FIG.

First, in the ratio calculator 47A, the IRE
Before light emission of D is started, the switch SW3 is turned on once, and the potential of the integration capacitor C3 is set equal to _Vref . Before the emission of the IRED, the switches SW1 and SW2 are turned on and the switch SW5 is turned off, and the feedback loop operates, so that the steady photocurrent of the PSD flows to the transistors Q3 and Q4 and does not flow to the bases of the transistors Q1 and Q2. The capacitors C1 and C2 are charged to a voltage corresponding to the steady light level.

The switch SW is synchronized with the emission of the IRED.
When the switch SW1 is turned off and the switch SW5 is turned on, the transistors Q3 and Q4 continue to flow only the steady-state photocurrent immediately before the IRED emission. The photocurrent due to the reflected light from the subject 5 of the IRED 3 depends on the incident position on the PSD, i
₁ and i ₂ . The signal currents i ₁ and i ₂ are multiplied by β (current amplification factor) by the amplification transistors Q1 and Q2, and flow through the diodes D1 and D2.

Here, assuming that the current flowing through the collector of the transistor Q5 is I _INT , the voltage relationship between the diodes D1 and D2 and the transistors Q5 and Q6 is expressed by the following equations (6) and (7).

[0090]

[Equation 11] Therefore, the integration capacitor C3 is I _INT, i.e., i ₂ /
A current proportional to (i ₁ + i ₂ ) flows, and the potential decreases.

When the switches SW1 and SW2 are turned on and the switch SW5 is turned off again in synchronization with the end of the IRED light emission, the feedback loop operates again, and the integration capacitor C is turned on.
The integration operation to 3 is also completed.

The IRED repeats the integration operation n times by emitting light n times at a predetermined interval T _INT during one light emission time t _INT . The above is the first integration operation.

Next, when the switch SW4 is turned on, electric charge was Tsu the integrating capacitor C3 is gradually discharged with a constant current I _G. Therefore, the potential of the integration capacitor C3 rises linearly, and when it reaches _Vref , the comparator C3
The output of OM1 is inverted.

The arithmetic unit 8 recognizes the distance to the subject 5 by measuring the time T ₂ from when the switch SW 4 is turned on to when the comparator COM 1 is inverted. The above is the second integration operation.

When the above is quantitatively analyzed, the amount of charge and discharge (Q = CV = i) in the first integration and the second integration is calculated.
Since t) are equal,

(Equation 12) From the above expressions (4), (7) and (8),

(Equation 13) Therefore, I / D is

[Equation 14] Becomes In other words, by determining the time T _2, the (10) can be obtained from the (object distance) ^-1 expression.

Next, the operation of the light quantity integration circuit 47B will be described.

From the COM terminal of the AFIC 47 to the C
The signal current i _s (= i ₁ + i ₂ ) flowing through the OM terminal is expressed by the following equation (11).

[0098]

(Equation 15) Here, τ _t and τ _j are the light emitting / receiving lenses 1, 2L, 2
The transmittance of R, dP ₀ / dΩ, is the light emission intensity [W
/ Sr] and R _P are the light receiving sensitivities of PSD 4L and 4R [A /
W], d _j is receiving lens 2L, clear aperture of 2R, F _t is the light projecting lens 1 F number, [rho is subject reflectivity, D is a subject distance. In addition, since ρ and D are constants that are determined by design, if this is set to A, the above equation (11) becomes the following (1)
Equation 2) is obtained.

[0099]

(Equation 16) Before the emission of the IRED, the switch SW11 is turned on at the same timing as the switch SW3, and the capacitor C5 is turned on.
Is discharged. Further, since the switches SW6 and SW7 are turned on before the emission of the IRED, the feedback loop by the amplifier A5 is formed,
The current flowing out of the M terminal is equal to the collector current of the transistor Q7 due to the current mirror of the transistors Q7 and Q9. This is through switches SW6 and SW7,
It becomes the collector current of the transistor Q8. Capacitor C
4 is charged with a charge that depends on the steady-state photocurrent.

Then, in synchronization with the IRED emission of the ratio operation,
Switches SW6 and SW7 are off, switches SW8 and SW
9 turns on and the switch SW12 turns off.

Therefore, the transistor Q8 includes the IRED
The steady-state photocurrent immediately before light emission is the transistor Q7 and the switch S
It flows through W8 and SW9. The signal current i _s (= i ₁ + i ₂ ) due to the IRED emission does not flow through the transistor Q8, but is charged in the capacitor C5. Therefore, the output voltage of the amplifier A6 is gradually lowered depending on the value of i _s. When the light emission of the IRED 4 is completed, the switch SW is again turned on.
6, SW7 and SW12 are on, switches SW8 and SW9
Is turned off, and a feedback loop is formed.

The above operation is repeated n times. afterwards,
When the switch SW10 is turned on, electric charges charged in the capacitor C5 is discharged at a constant current I _G. Therefore, when the potential of the amplifier A6 increases and reaches _Vref , the output of the comparator COM2 is inverted. The time T ₃ from the on switch SW10 to the comparator COM2 inversion measured by computing device.

When the above is quantitatively analyzed, the amount of charge charged and discharged in the first integration and the second integration is the same as in the previous case.

[Equation 17] From the expressions (12) and (13),

(Equation 18) Therefore, the value of ρ / D ₂ can be obtained by obtaining T ₃ .

[0104] In addition, from the following formula, it can be obtained from T ₃ i _s.

[0105]

[Equation 19] Then extensive theta _M is projected by driving both areas emitting portion and the spot light emitting unit, it will be described AFIC47 output when a plurality of subjects in the irradiation range is present.

There are n objects in the irradiation range of the IRED, the distance of the m-th object is D _m , the reflectance is ρ _m ,
The ratio of total radiation range and h _m. Therefore,

(Equation 20) It is. The signal currents i _1M and i _2M output from the PSD-L and PSD-R are the sum of the signal currents generated by the respective subjects. Also, i _SM is the sum of i _1M and i _2M . Based on the signal of the sum, the AFIC 47 recognizes that one certain subject is at the distance D _M.

Next, the operation of the flash system according to the second embodiment of the present invention will be described with reference to the general flowchart of FIG. In the second embodiment, two slave strobe devices having the same configuration as the slave strobe device shown in FIG. 1 are used (multi-slave mode).

First, it is determined whether or not the multi-slave mode is set (step S131). If the multi-slave mode is set (YES), the power supply control is performed using the codes of CH1 and CH2 as in the first embodiment. , Data communication is performed (steps S133 to S136), and charging of each slave strobe device is started (steps S137 and S13).
8).

Next, when the release button 18 of the camera is half-pressed (1R is turned on) (step S139), the charging completion display (step S140), and the distance measurement operation (step S1)
41), a photometric operation (step S142) is performed.

From these measurement results, it is determined whether or not the luminance required for light emission of the slave strobe device at the time of photographing is obtained (step S143). If it is determined that the luminance does not require light emission (NO), the normal mode process is performed (step S132), and if it is determined that the luminance is low requiring light emission (Y).
ES), the camera sequentially instructs each slave strobe device to perform pre-emission (steps S144 and S14).
5).

Light is received by the light receiving element (PSD) 12 of the camera, the result is integrated, and the amount of light required at the time of main light emission is calculated by the control circuit 1 (steps S146 and S14).
7) The information is transmitted to each slave strobe device together with the information on the light emission timing (steps S148 and S149).

Next, after the release button 18 of the camera is completely depressed (2R is turned on) and the lens is extended (step S151), a flash start signal is transmitted to each strobe device (steps S152 and S153). Shutter control, that is, exposure is performed (step S154).

Further, the synchronization of the strobe light emission is confirmed (step S155) and displayed (step S156). Thereafter, the film is fed (step S15).
7).

As described above, in the strobe system of the second embodiment, each strobe device is controlled in the same manner as in the first embodiment, and the main flash emits light simultaneously when the shutter of the camera is fully opened, or one of the strobe devices is used. It is also possible to adjust the light emission timing signal to emit light only when the aperture is fully opened.

As a feature of the second embodiment, since the first embodiment has only one light source, a shadow is generated on one side. However, in the second embodiment, the strobe of CH1 and the strobe of CH2 are used as objects. By arranging them on the left and right sides and emitting light so as to have the same light amount, a photograph in which shadows are not noticeable can be taken.

It is also possible to set the illumination ratio of the subject of CH1 and CH2 to a predetermined ratio.

Next, the operation of the flash system according to the third embodiment of the present invention will be described with reference to the general flowchart of FIG. 17 and the time chart of FIG.

The third embodiment is a modification of the multi-slave mode of the second embodiment shown in FIG.
In this mode, the built-in strobe emits light in addition to the slave strobe control of CH1 and CH2.

In this strobe system, charging of the built-in strobe is started before the operation shown in FIG. 16 (steps S131 to S157) (step S161), and after the shutter control, the built-in strobe emits light. The example is different.

In this strobe system, if the built-in strobe emits light to the extent that it controls the exposure, red-eye occurs.

Accordingly, the built-in strobe emits a small amount of light at a position where the aperture of the shutter is small, and emits light at the point where the CH1 strobe is the main light source and the CH2 strobe is the main light source as the main light source at the point where the aperture is fully open. .
In this way, by illuminating the three strobes, a natural shadow is formed, and a picture can be taken in the same manner as when a catch light is applied to a subject.

In the present invention, the PSD for AF is used as the light receiving element of the pre-projection. However, a light emitting element of the light measuring circuit or a dedicated light receiving circuit may be provided. The calculation of the light emission amount was performed by the control circuit 1 on the camera side.
1 may be performed. Although the transmitting and receiving circuits are both built in the camera and the strobe, they may be connected by an adapter.

As described above, in the strobe system of this embodiment, the slave strobe device emits a predetermined amount of infrared light before the main light emission, receives the reflected light of the subject on the camera side, and performs the necessary light emission at the time of the main light emission. Calculate the light emission amount.

The value is transmitted to the slave strobe device by blinking the infrared light emitting element of the camera, so that the main light emission appropriate for photographing can be performed.

In the present strobe system, the built-in strobe and the slave strobe device are individually controlled, so that only the slave strobe device can emit light. Also, you can take photos without red eyes. Further, since the strobe does not emit light before the photographing, the photographer or the subject does not judge that the photographing is completed.

Further, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications and applications can be made without departing from the spirit of the invention.

[0127]

As described above in detail, according to the present invention, the camera calculates a suitable light emission amount for the main light emission from the subject reflected light emitted by the slave strobe, and selectively performs the proper light emission for the main light emission. A strobe system can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a strobe light system as a first embodiment according to the present invention.

FIG. 2A shows a specific configuration of the receiving circuit shown in FIG. 1, and FIG. 2B shows output waveforms of each circuit.

FIG. 3 is a diagram illustrating an example of code data transmitted / received by the strobe system illustrated in FIG. 1;

FIG. 4 is a general cell flowchart showing the operation of the strobe light system shown in FIG. 1;

FIG. 5 is a flowchart for explaining a charge completion flag of the strobe light system shown in FIG. 1;

FIG. 6 is a first half of a flowchart for describing calculation of a light amount and a light emission timing necessary for main light emission of the strobe system shown in FIG. 1;

FIG. 7 is a second half of a flowchart for describing calculation of a light amount and a light emission timing required for main light emission of the strobe light system shown in FIG. 1;

FIG. 8 is a flowchart for explaining a main light emission operation of the strobe system shown in FIG. 1;

FIG. 9 is a timing chart of the main light emission operation of the flash system when the subject is at a long distance.

FIG. 10 is a timing chart of the main light emission operation of the flash system when the subject is at a short distance.

FIG. 11 is a diagram illustrating a schematic configuration of a distance measuring circuit illustrated in FIG. 1;

FIG. 12 is a diagram showing an internal configuration of an autofocus arithmetic integrated circuit (AFIC) in the distance measuring circuit of FIG. 1;

FIG. 13 is a timing chart for explaining a ratio calculation operation and a light amount integration operation.

FIG. 14 is a diagram illustrating an example of a format of communication data employed in the embodiment;

FIG. 15 is a diagram illustrating a relationship between an aperture value and an apex value of a shutter fully open time.

FIG. 16 is a general flowchart for explaining the operation of the strobe system according to the second embodiment of the present invention.

FIG. 17 is a general flowchart for explaining the operation of the flash system according to the third embodiment of the present invention.

FIG. 18 is a time chart for explaining an operation of the strobe system shown in FIG. 17;

[Explanation of symbols]

1,21 ... control circuit, 2,22 ... transmission circuit, 3,23,
31 ... infrared light emitting diode, 4,24 ... receiving circuit, 5,
25 ... photodiode, 6,26 ... charging circuit, 7,2
7: Light emission start circuit, 8, 28 ... Light emission stop circuit, 9, 29
... A strobe light emitting section, 10 a distance measuring circuit (AF), 11 an infrared light emitting diode (IRED), 12 a light position detecting element (PSD), 13 a photometric circuit, 14 a photodiode, 15 an exposure control circuit, 16 ... Lens drive circuit, 17
... Film feed circuit, 18 release button, 30 light emitting circuit, 32 channel setting switch.

Claims (1)

(57) [Claims] 1. A strobe system comprising a camera and a strobe device which can be arranged at a position spatially distant from the camera, wherein the strobe device includes: a receiving unit for receiving data from the camera; And a pre-emission means for performing a pre-emission of a predetermined amount of light on the camera, the camera comprising: a transmission means for transmitting data to the strobe device; and Pre-flash command means for causing the strobe device to execute the pre-flash via receiving means; receiving reflected light from a subject at the time of the pre-flash, and determining a main light emission amount required for photographing based on the received light amount The main light emission amount by the light emission amount calculation means is transmitted to the strobe device via the transmission means and the reception means before photographing. Communication means for transmitting light emission timing data relating to the main light emission timing to the flash device in connection with a photographing operation, wherein the flash device transmits the main light emission amount transmitted from a camera. A flash system characterized by controlling light emission based on data.