JPH0933992A - Stroboscopic light control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain both of light control action intended by a user and automatic optimum right control action which cannot be executed simultaneously before. SOLUTION: This light control system is provided with a first mode in which the light pre-emitting action is executed by an operation member and a second mode in which the light pre-emitting action is executed before a photographic action is started(just before a mirror is set up in the case of a single-lens reflex camera) by depressing a release button. Besides, it is equipped with light control means 22 and 39 controlling the main light emitting action by executing the partial light control action in the first mode and executing the evaluation light control action in the second mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a strobe light control system which separately measures reflected light due to pre-light emission and controls main light emission based on the light measurement value.

[0002]

2. Description of the Related Art Conventionally, reflected light by pre-emission of a strobe device is divided into photometers, an abnormal reflection object such as a gold folding screen is detected from the output of each divided sensor, and TTL dimming of film surface reflection corresponding to the area is detected. There was a strobe dimming system that dimmed excluding the sensor area.

Further, there is a so-called FELK system, which is a manually operated pre-emission system, which measures reflected light due to pre-emission of a strobe device and emits a predetermined amount of light emission during main emission based on the stored strobe emission amount. there were.

[0004]

However, in the above-mentioned conventional example, since the systems are different from each other, there has been a demand for a new strobe system which can obtain a consistent system and operability while inheriting the advantages of both systems.

(Object of the Invention) The object of the present invention is to achieve stroboscopic light control that can achieve both dimming reflecting the user's intention and automatic optimum dimming. To provide a system.

[0006]

In order to achieve the above object, according to the present invention, when an operation member for starting pre-emission is operated, pre-emission is performed in response to the operation, and If the reflected light from the pre-flash is metered in the divided metering area corresponding to the selected focus point, partial light control is performed, and if the release operation is performed without operating the operation members, start shooting. Prior to this, pre-flash is performed, and the reflected light due to this pre-flash is weighted to the distance measuring point selected by the closest point priority among all the distance measuring points that may be selected, and each divided metering is performed. A first mode of pre-flashing is provided by the operation member, which is provided with a light control unit for performing metering in the area and evaluation metering, and prior to the start of shooting by pressing the release button (just before the mirror is raised in a single-lens reflex camera). To) A second mode of performing, in the first mode, and controls the main light emission by the partial light control, in the second mode, so that the evaluation dimming.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail based on the illustrated embodiments.

FIG. 1 is a view showing main sensors, optical members, etc. of a camera and a strobe device, where 1 is a film surface and 2 is a film surface.
Is a penta prism, 3 is a main mirror, 4 is a sub-mirror, 5
Is a superimposing prism. A focusing plate 6 has a micro-prism array for superimposing in the center thereof. Reference numeral 7 is a photometric lens, 8 is a prism for guiding light to the line-of-sight detection circuit 32, and 9 is the photographer's eyes.

Reference numeral 38 is a strobe device, in which a reflection shade 45 and a xenon tube 44 are arranged, and further, SPC (silicon photodiode) 1 of 49 for monitoring the amount of emitted light and its peak value (emission intensity) 51 are monitored. SPC2 of.

The light emitted from the strobe device 38 is reflected by a subject (not shown), passes through the lens 23 and the main mirror 3,
It is guided to the AF sensor 31 by the sub mirror 4. The light reflected by the main mirror 3 having a half mirror at the center reaches the eye 9 of the photographer through the focusing plate 6 and the pentaprism 2.

The image on the focus plate 6 reaches the photometric sensor 21 through the photometric lens 7 via the pentaprism 2. The in-finder display 30 is composed of a backlight, an LCD, a prism, etc., and displays information on the bottom of the finder.

27 is a display for superimposing,
The light from here is reflected by the main mirror 3 via the prism 5, and the direction can be changed by the micro prism array on the focusing plate 6. As a result, the photographer can visually check the following distance measuring frames (distance measuring points) as a superimposed display.

FIG. 2A is a diagram showing a layout in the finder 64, and 61, 62, 6 in the finder 64.
Reference numerals 3 are focus detection points displayed in the left, middle, and right superimposes, respectively. Reference numeral 65 denotes an LED (infrared light emitting diode) that is turned on when focusing. Reference numeral 30 denotes an LCD display in the finder shown in FIG. 1, which displays shutter speed and aperture value in 7 segments, and also has a strobe charge completion mark 30.
The display unit has a LOCK mark 30b indicating a and a FELK state and an HS mark 30c indicating high-speed tuning.

FIG. 2B is a layout view of the photometric sensor 21. The photometric sensor 21 is divided into six photometric areas S0 to S5. Particularly, the divided photometric sensors S0 to S2 are each of the distance measuring points described above. It corresponds to the positions of 62, 61 and 63.

FIG. 2C is a layout of the AF sensor 31.

FIG. 3 is a block diagram showing the electrical construction of the camera, lens and strobe device.

Reference numeral 21 denotes a divided photometric sensor (including a signal processing unit for generating a photometric signal). As shown in FIG. 2B, a central divided sensor S0 of 10 and a divided photometric sensor S of 11 left.
It has divided photometric sensors S5 and the like on the outer periphery of 1 and 12.
13 is a compression diode D0, and 14 is an operational amplifier AP0
At the same time, the photocurrent of the split photometric sensor S0 is logarithmically compressed and converted into current / voltage. Similarly, also in the operational amplifier AP1 of the 15 compression diodes D1 and 16, the operational amplifier AP5 of the compression diodes D5 and 18 of 17, etc., the photocurrents of the sensors S1 and S5 are logarithmically compressed and converted into current / voltage.

These outputs are respectively input to 19 multiplexers MPX2, a photometric signal of any of the divisions S0 to S5 is selected by the selection signal AESEL of the MPU 22 of the camera, and 20 AD converters AD2 produce digital photometric values. , MPU22.

An interchangeable lens 23 is an AF control unit 24 for focusing, a zoom detection unit 25, and an aperture control unit 26.
And is connected to the MPU 22 of the camera by a lens communication bus.

On the camera side, 27 is a display for displaying a distance measuring point by superimposing, 28 is a shutter control section, 29 is a sequence control section, 30 is a finder display, 31 is an AF sensor, and 32 is a line of sight detection. It is a department. Further, 37 is a photometric switch SW1, 36 is a release switch SW2, and 35 is a FELK button. Reference numerals 33 and 34 denote distance measuring point selection switches, and the AFSEL input of the MPU 22 of the camera can take values from 0 to 3 depending on the states of these switches.

The 38 strobe devices and the camera are connected by a strobe communication bus.

The strobe device 38 has a system control circuit 39.
And executes a strobe control sequence described later with reference to FIG. In addition, the strobe device 38 includes the following components.

Reference numeral 44 is a xenon tube, 45 is a reflection shade, 46 is a trigger control circuit, 48 is a charge control circuit, 47 is a zoom control circuit, and 43 is a light emission control circuit such as an IGBT.
49 SPC1 directly receives light from the xenon tube 44,
This output signal is integrated by the compression integration circuit 50. This integrated value is transferred from the 45 AD converter AD1 to the system control circuit 3
The DA converter DA1 of 56 is read out at 9
Output voltage is compared with the comparator 1 of 53, and when the integrated value reaches the output voltage, light emission can be stopped, that is, so-called dimming control is possible.

When performing flat light emission, an output voltage corresponding to the light emission intensity is obtained from the photocurrent of the sensor SPC2 51 by the current-voltage converter 52, and the output voltage and the level of the DA converter DA2 57 are set to 54. The comparison is made by the comparator 2. As a result, when the output voltage of the DA converter DA2 is exceeded, the light emission is stopped, and when it goes down, the light emission is continued and the flat light emission can be maintained.

This is the time until the timer 1 of the one-shot timer 40 counts up because the output of the timer 1 of 40 and the output of the comparator 2 are ANDed by the AND gate 1 of 41. Keeps emitting flat light.
42 is a multiplexer MPX1 and two channels C
It has H1 and CH2 and is switched by the system control circuit 39. That is, the system control circuit 39 selects the channel CH1 when performing flash light emission and the channel CH2 when performing flat light emission.

FIG. 4 is a flow chart which explains the basic concept of the main light emission control system using pre-light emission in an easy-to-understand manner.

Step # 01 is a portion for performing outside standard light photometry, and its photometric value is expressed as A (i), i = 0 to 5. i
Corresponds to the divided photometric sensors S0 to S5, and external light photometric values of the sensors are represented as A (0) to A (5). The next step # 02 is the part that performs pre-flat flash metering.
The photometric value of the reflected light from the subject at this time is F
(I). Then, in the next step # 03, the control value EVt of the camera is obtained from the control time TV and the control aperture value AV.

Step # 04 is a calculation part which is the core of this control, and the denominator shown in the figure extracts how much the pre-emission influences the photometry by "2 ^{F (i)} -2 ^{A (i)} ". However, by dividing by the degree of influence required for the numerator, in order to be appropriate for each area of each photometric sensor at the time of main light emission, the peak value of multiple times the light emission intensity (peak value) of pre-emission Is calculating what should be. This is 2 for each sensor
It is represented by ^{G (i)} .

For example, when the film sensitivity is ISO100 and the flash is normally emitted in the dark of EV5,
Assuming that control is performed at 1/60 seconds and F5.6 in consideration of tuning time, the control value is "EVt = TV + AV = 6 + 5 = 1".
1 ". Since A (i) at this time is almost EV5, the numerator on the right side of step # 4 is calculated as “2 ^EVt −2 ^{A (i) ≈2.
EVt} ”, and the second term can be almost ignored.

That is, when the outside light is significantly smaller than the control value EVt, it may be considered as "G (i) ≈EVt-F (i)". Of course, this is based on the premise that the photometric value F (i) by pre-flat emission is also relatively larger than A (i).

The photometric value F (i) of the pre-flat emission is EV
If there are 13, EVt = 11 in the above example, so that “G (i) = 11−13 = −2” during main light emission,
If the control is performed with a crest value that is two steps smaller than the crest value (emission intensity) of the pre-flat light emission, the control EVt = 11 provides a proper exposure.

Step # 05 is a part for performing strobe control with close priority by extracting the minimum value of the flat light emission gain G (i) obtained for each area of divided photometry.

In general, during flash photography, the main subject is wide in the center and most often exists closest to the frame. Therefore, such an algorithm is adopted as a kind of evaluation light control. In addition to simply selecting the minimum value, a selection with an emphasis on the center can be considered. In addition, if there is a white table cloth in the foreground as it is, there is also a problem that the main subject behind it will be controlled to the under side, so it seems that there is plenty of room to consider the algorithm around this. , The basics of evaluation dimming are close, but a priority algorithm will be the principle.

In the next step # 06, it is judged whether or not the control TV is faster than the tuning time.
The process shifts to 7 and the main light emission is performed by flat light emission.

As described above, in step # 07, if the emission intensity (peak value) is stronger by the G step of the pre-emission peak value, the exposure is almost perfect. At this time, it is necessary to continue the light emission from before the front curtain puts out the aperture until the rear curtain completely covers the aperture.

On the other hand, in step # 06, if the control TV is not faster than the tuning time, the process proceeds to step # 08. The calculation at the time of flash light emission is described in this step # 08.

At the above step # 07, the film exposure becomes appropriate with the total sum of the light passing through the slits of the shutter at the emission intensity of the main flat light emission.
When flash light emission integral value of the preliminary emission time T0 measured at 2 and K _p, the peak value is "K _p / T0", and peak value required _{"(K p / T0) × 2} G " since the total emission amount If the control shutter speed is T1, then “(K _p / T0) × 2
^G x T1 ". Therefore, for the strobe device 38, the main flash light emission integral gain γ shown in step # 08.
The By instructing the strobe device 38 side is seen that may be controlled by the main light emission integral value of 2 for γ th power of the integrated value K _p of the pre-light emission in the next step # 09.

As described above, by measuring the pre-flat light emission and measuring the total amount of light emission by the strobe device 38 side, if the slit exposure time is the main light emission time, the peak value of the pre-light emission is 2 ^{For G} times and flash emission seconds, a consistent strobe light control system can be obtained simply by controlling the strobes by multiplying the integral amount of pre-flash by 2 to the power of γ.

Before explaining the sequence flow of the camera, the sequence flow of the strobe control circuit 39 shown in FIG. 3 will be described with reference to FIG. This can be more easily understood by comparing with the circuit block diagram of the strobe device 38 in FIG.

System control circuit 3 in strobe device 38
Reference numeral 9 denotes, for example, a microcomputer that controls communication and a sequence in the device, and first performs charge control in step # 11. Specifically, the voltage of the battery is boosted to charge a main capacitor (not shown) at about 300V. In FIG. 3, 48 charging control circuits do this.

The next step # 12 is a part waiting for communication from the camera, and when there is data reception, step # 1.
The data received by communication in 3 is stored as variables such as peak value gain G, flash light emission gain γ, pre-flat light emission time T0, and main flat light emission time T2. Next, in step # 14, the pre-flash command is issued from the camera, in step # 15, the main flat flash command is issued, and in step # 1
In step 6, while waiting for a command indicating whether or not the main flash light emission command has come, the process repeatedly loops until the data reception is detected in step # 12.

When the pre-light emission command is received in step # 14, a predetermined peak value (light emission intensity) h is received in step # 17.
Substituting ₀ into h, sets it in the DA converter DA2 of 57 for controlling the peak value in the next step # 18, and in the subsequent step # 19, the multiplexer MPX is used for flat light emission.
1 is set to channel CH2. Then, in step # 20, the light emission time T0 is preset in the timer 1 of 40, and in the next step # 21, the trigger control circuit 46 is turned on to start the timer 1.

As a result, the xenon tube 44 starts to emit light. Then, the light emission is monitored by SPC2, and turned off when the peak value (light emission intensity) becomes higher than h ₀ set in the DA converter DA2 of 57, and turned on when it becomes lower than h _0. The output of the device 2 changes, and stable flat light emission can be maintained. This light emission stops when the timer 1 of 40 counts up.

Therefore, in step # 22, the end of the timer 1 is waited, and when it is finished, the integrated value of the pre-flat emission is AD-converted by the AD converter AD1 in step # 23 and stored as K _p . And again step # 1
Return to 1.

When the command for main flat emission is received in step # 15, the gain times 2 ^G of the peak value h ₀ of pre-emission is calculated in step # 24, and the next step # 15
At 25, the DA converter DA2 57 is set. And
In step # 26, the flat light emission is selected, in the next step # 27, the main flat light emission time T2 is set in the timer 1, and then the flat light emission from step # 21 to step # 23 is executed.

When the main flash command is received in step # 16, the pre-flash integrated value K _p is received in step # 28.
The integral value Kx corresponding to 2 to the power of γ is calculated and set in the DA converter DA1 of 56 in the next step # 29. Further, in step # 30, MPX1 is set to the channel CH1 and the flash light emitting circuit is connected. Continued Step # 31
Turn on the trigger circuit with.

As a result, the xenon tube 44 starts flashing light emission, photoelectrically converted by the SPC1 whose light quantity is 49, integrated by the compression integration circuit 50, and set by the DA converter DA1 whose integration quantity is 56. When it reaches, the comparator 1 of 53 is inverted and the flash light emission is completed.

In step # 32, it is sufficient to wait up to 100 ms until the end of the flash emission, so the wait is 100 ms for the time being. Here, after waiting for the output of the comparator 1 to be inverted, the next step # 1
You may go back to 1.

As described above, when h ₀ is a predetermined value during pre-flat light emission and T 0 is communication data from the camera, flat light emission occurs at light emission time T ₀ with peak value h ₀ , and gain G during main flat light emission. And the light emission time T2 from the camera, a flat light emission is performed at the light emission time T2 with the peak value “h ₀ × 2 ^G ”, and during the main flash light emission, the gain γ instructed by the camera is obtained based on the integrated value K _p of the pre-flat light emission. Accordingly, the flash light is emitted with the integrated flash light amount “K _p × 2 to the power of γ”.

FIG. 6 shows a main sequence flow of the camera.

Start at step # 41, step #
At 42, it is determined whether or not the FELK button 35 has been pressed.

The FELK is like an AE lock strobe version. When the FELK button 35 is pressed, the strobe device 38 is pre-emitted, and the strobe emission amount at the time of release is determined based on the reflected light amount at that time. It is a thing. In addition, in order to improve its operability, a relatively narrow area,
That is, it is convenient to perform the measurement in a region corresponding to partial photometry.

Therefore, if a subject for which proper strobe exposure is desired is placed at a distance measuring point or the like and the FELK button 35 is pressed and pre-flash is performed, for example, framing is changed, which is different from the conventional TTL dimming. Since the reflected light of pre-flat emission is already measured as the information depending on the distance and the reflectance of the main subject, proper exposure can be obtained.

In order to give time for changing the framing, the timer is set in step # 43 in order to extend the measurement timer during the FELK. Then, in step # 44, the pre-light emission a is called. Steps below #
Although 57 also has a pre-emission b, the pre-emission b is measured by using most of the divided photometry sensors to perform so-called evaluation dimming. In this pre-emission a, one pre-emission b is linked to a distance measuring point or the like. Since it is desirable to use narrow partial photometry in terms of operability, the pre-flat light emission time is set to be considerably shorter than the pre-light emission b to save energy.

At the next step # 45, the flag PREEND indicating the FELK state is set to "1".

Next, at step # 46, the photometric switch SW
When 1 is pressed, the line of sight is detected in step # 47. This is because when the AFSEL switches for selecting the distance measuring points 33 and 34 are 0 to 2, it is possible to select any of the center, left and right distance measuring points. Therefore, the line of sight is not detected and the process immediately proceeds to step # 48. , AF control is performed based on the focus detection point. Also,
When "AFSEL = 3", AF control is performed at step # 48 at the distance measuring point selected by the sight line detection.

When the photometric switch SW1 is off in step # 46, the photometric timer is counted in step # 49, and if the time is up in step # 50, the FELK status is displayed in step # 51 "PREEND =".
Clear "0" and return to step # 41.

Further, during the photometry timer in step # 50, or if the AF control is completed in step # 48, normal photometry is performed in step # 52. Further, the shutter speed TV and the aperture value AV are determined by the evaluation photometry, the program diagram and the like based on the photometric value. And step #
Display is made at 54.

Next, if the release switch SW2 is off in step # 55, the process returns to step # 42 and the same operation is repeated. If the release switch SW2 is turned on, the release sequence is started.

If it is during FELK, step # 5.
Since "PREEND = 1" in 6, the next step # 58
Calculate the gain with. When not in the FELK, the pre-light emission b is performed in step # 57 before the mirror is raised. this is,
After that, since the main light emission is excluded, it is called "batch light emission".

In the G and γ calculation of step # 58, FEL
Gain calculation corresponding to one sensor and a plurality of sensors is performed by K and collective light emission. Further, the gain G for flat light emission and the gain γ for flash light emission are obtained depending on whether or not the shutter speed is faster than the synchronization time (the highest speed when the shutter is fully open).

In the next step # 59, the main mirror 3 is raised, and in the next step # 60, shutter control is performed. At the same time, various commands for flash data communication and flash emission are also communicated.

In the next step # 61, the mirror is down, the shutter is charged, and the film is wound up.
At 62, the inside of FELK is released, and the process returns to step # 42.

Next, each subroutine will be described.

FIG. 7 is a subroutine of normal photometry executed in step # 52 of FIG.

Here, in order to reduce the influence of flicker such as a fluorescent lamp, average photometry is performed for about 10 ms. Here, there are six photometric sensors, i = 0 to 5, and each photometric sensor is AD-converted eight times and averaged. Also, since it is more average if the sampling is distributed as much as possible for 10 ms, step # 74
In the double loop of Step # 75 and Step # 75, the sensor switching is realized by going to Step # 76. After all, since AD conversion is performed “6 × 8 = 48 times” within 10 ms, “10 ms ÷ 48 times = 208” in step # 79.
The weight of "μs" is included.

Steps # 74 to # 81 (Step # 79
If it takes a long time to execute, it should be deducted in advance by 208 μs.

In steps # 71 to # 73, first, the variable SU
Clear M (i). Then, the sensor is selected in step # 76, AD conversion is performed in step # 77, and the total sum for each photometric sensor is added to SUM (i) in step # 78. This is repeated 48 times for 10 ms in a double loop, then the average photometric value M (i) for each photometric sensor is obtained in steps # 82 to # 84, and the process returns to the main routine in step # 85.

Next, the TV / AV calculation routine executed in step # 53 of FIG. 6 will be described with reference to FIG.

At step # 86, the control EV value EVt is obtained based on the photometric value M (i). Originally, it is necessary to perform level, gain correction, temperature correction, various corrections by the open aperture of the lens and ISO sensitivity, that is, SV addition, etc. on the photometric value, but this is well known in the present case and is important. Since it is not the point, it is assumed that it is automatically processed in the 20 AD converters AD2. Further, in step # 86, in order to obtain EVt from the photometric value M (i) of the split photometric sensor, focus on focus points such as evaluative photometry and evaluation calculation based on backlight compensation, lens distance information, etc. may be performed. is there.

At step # 87, TV and AV are obtained from the program diagram based on the obtained control EVt. In TV priority and AV priority other than the program mode, TV,
One of the AVs is preset and the other is calculated.
In step # 88, the process returns to the main routine in FIG.

Next, the display subroutine of step # 54 in FIG. 6 will be described with reference to FIG.

In step # 91, the shutter speed TV is displayed on the finder display 30, the aperture value AV is displayed in the next step # 92, and the focusing LED 6 is displayed in the following step # 93.
In step # 94, AF display is carried out at 5, and superimposes 61 to 63 are displayed at the distance measuring points. This is 27 in FIG.
By selectively turning on the LEDs (there are actually three), the distance measuring points 61 to 63 corresponding to the LEDs are seen to shine.

Next, at step # 95, if the shutter speed is higher than that at the sync time, then at step # 96 the strobe charge completion mark 30a and the HS mark 30c, that is, the high speed sync is displayed. Otherwise, step # 9
At 7, only the strobe charge completion mark 30a is displayed. Further, in step # 98, it is determined whether or not FELK is in progress, and F
Since "PREEND = 1" during ELK, step # 9
At 9, the display of the LOCK mark 30b is added.

In the next step # 100, when the AE mode is set, in step # 101, the flash-entanglement display is not turned on and the process returns in step # 102.

Next, the pre-emission a subroutine executed in step # 44 of FIG. 6 will be described with reference to FIG.

The pre-light emission a means pre-light emission for FELK which is executed by pressing the FELK button 35.

First, in step # 111, high-speed photometry a is performed. High-speed photometry a is shown in FIG. 11, but step # 1
First, at 41, the distance measuring point is determined. This distance measuring point determination subroutine will be described with reference to FIG.

At step # 171, 2-bit AFSEL is selected.
Read the switch, and in step # 172, "AFSEL =
3 ", that is, in the line-of-sight detection mode, step # 17
The distance measuring point whose line of sight is detected in 3 is P. The default is “P = 0”, that is, the center. "AFSEL = 0
In the case of "2", since an arbitrary distance measuring point is selected, "P = AFSEL" is set in step # 174. In step # 175, FIG.
Return to the routine.

Based on the distance measuring points determined in this way, in steps # 143 to # 148 of FIG.
A photometry of 0 μs is performed.

At step # 142, SUM = 0 is set, at step # 144, the sensor corresponding to the focus detection point P is selected, at step # 145 the AD value is obtained, then at step # 146, the integration is performed, and then at step # 147. And wait for 12.5 μs. This is Step # 143, Step # 148
Repeat 8 times. This is 1/8 in the next step # 149
By doing so, the photometric value M (P) is obtained, and step # 150
Then, the process returns to the routine of FIG.

In FIG. 10, when the process returns in step # 111, the constant ambient light photometric value A (P) is obtained in step # 112.
As a memory. Next, in step # 113, the pre-light emission time T0 is set to 200 μs for communication.

In step # 114, a pre-flash command is issued to the strobe device 38. Although the high-speed photometry a is 100 μs, the pre-flash time “T0 = 200 μs” is set because the peak value becomes unstable because the xenon tube 44 is not in the steady state for a while at the start of the flat flash of the strobe device 38. Since the photocurrent of the photometric sensor suddenly increases, the photometric value output also becomes unstable for a while.
A pseudo waiting time (dummy weight) of “00 μs = 100 μs” is entered in step # 115. When the dummy weight is finished, the strobe device 38 measures the reflected light of the subject that is flatly emitted at the peak value h ₀ by calling the high-speed metering a in the next step # 116, and the subsequent step # 116.
At 117, the data is stored in F (P). This will be step # later
It is used when the gain calculation G (P) is obtained at 182. Then, in step # 118, the process returns to the main routine.

Next, the pre-flash b subroutine executed in step # 57 of FIG. 6 will be described with reference to FIG.

This is not activated by the FELK button 35, but is activated by the release switch SW2. In order to improve the operability of the release switch SW6, there are six dimming balances for adjusting the dimming balance of the subject in the entire frame. Pre-meters using all photometric sensors.

First, in step # 121, high-speed photometry b is performed. The subroutine for this high-speed photometry b is shown in FIG.
This will be described with reference to FIG.

In steps # 153 to # 158, the sensor Si is AD-converted eight times in 100 μs, and the average value is obtained as M (i) in step # 159. These steps # 153 to # 159 correspond to the above-mentioned steps # 143 to # 149, respectively.

In step # 152, the work area "SUM =
It is cleared as "0". Here, in step # 151, the photometric values for all six sensors are obtained in a loop between step # 160 and step # 151, but the order is reversed from the normal from the divided photometric sensors S5 to S0. this is,
Although it does not interfere with ambient light metering, as described above, in the case of pre-flat emission, the output of the photometric sensor is unstable for a while after the start of emission due to the circumstances of the xenon tube and photometric sensor. Certain photometric sensor S0
This is because it is better to rotate S2 and S2 as late as possible and AD a clean value.

Returning to the routine of FIG. 13 in step # 161, the ambient light stationary light photometric value is stored as A (i) in steps # 122 to # 124. Then step # 1
At 25, the pre-light emission time is set to “T0 = 700 μs”. This is because the high-speed photometry b takes a total of 600 μs, so that in the next step # 127, the unstable light emitting region at the rising of the pre-flat light emission is avoided at the weight of 100 μs. In step # 125, “T0 = 700 μs” is communicated to the strobe, and in the next step # 126, the pre-flash command is issued, and the strobe device 38 starts flashing.

Next, after waiting for 100 μs in step # 127, high-speed photometry b is performed again in step # 128. Then, the photometric value obtained by measuring the reflected light of the subject of the pre-flat emission with each of the divided photometric sensors is determined as steps # 129 to # 131.
Is stored in F (i). Then, in step # 132, the process returns to the main routine of FIG.

Now, A (i) in step # 121 and F (i) in step # 128 are about 700 times.
Although the time is separated by μs, this is because the photometric value at the same time is desirable for performing the calculation “2 ^{F (i)} −2 ^{A (i)} ” for removing the external light component from the strobe light later. This is much smaller than the flicker synchronization of 10 ms, so I think that there is no problem, but for this reason, A (i) metering and F
(I) The photometry is continuous.

This means that the A (P) photometry in step # 111 and the F (P) in step # 116 for the pre-light emission a.
Photometric conditions are better. At this time, the time difference is only 2
Since it is 00 μs, the influence of flicker can be almost completely removed.

Next, the gain G, γ calculation subroutine executed in step # 58 of FIG. 6 will be described with reference to FIG.

This has already been explained in the section of the concept of the main light emission control system by pre-light emission in FIG.

In steps # 181 to # 183, the gain G is set.
The calculation for obtaining (i) is the same as step # 04.

Step # 185 is the same as step # 05 and is a so-called close-up priority evaluation light control in which G is obtained from G (i). However, step # 185 is executed when the so-called collective light emission is not being performed in step # 184, and G (P) which depends on the distance measuring point P is used in the case of FELK.
Is adopted as G in step # 186. Step # 1
A control shutter 87 extends the control shutter speed TV (apex) in real time to T1.

At step # 188, the flash gain γ is obtained for the time being, including when the speed is higher than the tuning time. This has been described in step # 08. Then, in step # 189, the process returns to the main routine of FIG.

Next, the shutter control and strobe light emission command subroutine in step # 60 of FIG. 6 will be described with reference to FIG.

When the high speed shutter is selected in step # 191,
In the next step # 192, the crest value gain G is transmitted, and in the next step # 193, the shutter speed T1 is added to the shutter curtain travel time by the safety margin αms, and T2 is used as the main flat emission time, and strobe communication is performed. A light emission command is issued at 194. Then, in step # 195, the front curtain is started.

When the shutter time T1 is waited in step # 196, the trailing curtain is started in the next step # 197,
In the following step # 198, the process waits for 100 ms, or waits for the completion of the trailing curtain running, and then returns to the main routine of FIG.

When the shutter speed is low in step # 191, the flash gain γ is communicated in the next step # 200, the front curtain is started in the following step # 201, and the shutter speed T1 is counted in the next step # 202. Start. Then, in step # 202, after the completion of the front curtain traveling, in step # 204, a main flash emission command is issued. The step # 203 may be performed with the X contact turned on. When the shutter speed T1 is counted up in step # 205, the trailing curtain start process is executed in the previous step # 197, and when the trailing curtain travel is completed, the process returns to the main routine of FIG. 6 in step # 199.

According to the above-mentioned embodiment, in the system in which the reflected light of the object due to the pre-flat emission is divided and the emission intensity of the main emission or the emission amount is controlled based on the photometric value, the pre-emission is manually operated. Do,
There is a so-called first mode of FELK and a second mode in which pre-light emission is performed immediately before the mirror is raised by pressing the release switch without performing the FELK operation. In the first mode, an arbitrary selection set by the photographer is provided. By performing the main strobe light control in the partial metering area corresponding to the distance measuring point or the distance measuring point selected by the line of sight, it is possible to provide excellent operability that reflects the user's intention of FELK. In order to reflect the photographer's intention to take it safely in the second mode, a so-called evaluation based on close-point priority in a plurality of photometry areas including a plurality of focus detection points near the center that may be selected. A strobe light control system for light control was realized.

More specifically, the so-called flat emission is used for pre-emission, the amount of emission is directly integrated on the strobe side, and open metering is performed by the photometric sensor of the camera.
In order to improve the operability, there is a process of (1) and a second process of instructing how many times the integral value of the pre-flash should be emitted so that the strobe emission amount becomes appropriate with the control EV value during the main emission. The so-called F that pre-flashes by manual operation
It has a first ELK mode and a second mode in which pre-flashing is performed immediately before the mirror is raised by pressing the release switch without performing the FELK operation. In the first mode, flash control is performed by partial light control, and In addition, the flash dimming system with excellent operability can be realized by performing the evaluation dimming in the second mode.

(Correspondence between Invention and Embodiment) In the above embodiment, the FELK button 35 corresponds to the operating member of the present invention, and the divided photometric sensors 10 to 12 (S0 to S5) correspond to the photometric means of the present invention. The system control circuit 39 corresponds to the flash control means of the present invention, and the MPU 22 and the system control circuit 39 correspond to the dimming control means of the present invention.

The above is the correspondence relationship between each configuration in the embodiments and each configuration of the present invention, but the present invention is not limited to the configurations of these embodiments, and the functions shown in the claims or It goes without saying that any structure may be used as long as the function of the embodiment can be achieved.

(Modification) Although the present invention is applied to a single-lens reflex camera as an example, a lens shutter camera,
It is also applicable to cameras such as video cameras.

Further, although the case where the external strobe device and the camera are combined is assumed, the invention can be similarly applied to a camera with a built-in strobe.

[0108]

As described above, according to the present invention,
When the operation member for starting the pre-emission is operated, the pre-emission is performed in response to this operation, and the reflected light by the pre-emission is metered in the divided metering area corresponding to the selected focus area. However, when partial light control is performed and the release operation is performed without operating the operation member, pre-emission is performed prior to the start of shooting, and reflected light from this pre-emission can be selected. Among all the distance measuring points with good performance, the distance measuring points selected by prioritizing the closest point are weighted, metering is performed in each divided metering area, and the dimming control means for performing the evaluation metering is provided, and the operation member It has a first mode that emits light and a second mode that emits pre-light by pressing the release button prior to the start of shooting (immediately before the mirror is raised in a single-lens reflex camera). By light And controls the emission light emission, in the second mode, so that the evaluation dimming.

Therefore, it is possible to achieve both the dimming that reflects the user's intention and the optimum dimming automatically.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a main part of a camera and a strobe device according to an embodiment of the present invention.

2 is a diagram showing a state in a viewfinder of the camera of FIG. 1 and regions of a photometric sensor and an AF sensor.

FIG. 3 is a block diagram showing an electrical configuration of the camera shown in FIG.

FIG. 4 is a flowchart showing an operation during main light emission control by pre-light emission in the embodiment of the present invention.

FIG. 5 is a flowchart showing an operation during strobe control in the embodiment of the present invention.

FIG. 6 is a flowchart showing a main operation of the camera in the embodiment of the present invention.

FIG. 7 is a flowchart showing a normal photometry subroutine executed in FIG.

FIG. 8 is a flowchart showing a TV / AV calculation subroutine executed in FIG.

9 is a flowchart showing a display subroutine executed in FIG.

FIG. 10 is a flowchart showing a pre-emission a subroutine executed in FIG.

11 is a flowchart showing a high-speed photometry a subroutine executed in FIG.

FIG. 12 is a flowchart showing a focus detection point selection subroutine executed in FIG. 11.

FIG. 13 is a flowchart showing a pre-light emission b subroutine executed in FIG.

FIG. 14 is a flowchart showing a high-speed photometry b subroutine executed in FIG.

FIG. 15 is a flowchart showing a G, γ calculation subroutine executed in FIG.

FIG. 16 is a flowchart showing a shutter control and strobe light emission command subroutine executed in FIG.

[Explanation of symbols]

 10 to 12 split photometric sensor 22 MPU 23 lens 33, 34 focus detection point selection switch 35 FELK button 38 strobe device 39 strobe control circuit 40 timer 43 light emission control circuit

Claims (4)

[Claims] 1. In a strobe light control system in which the reflected light from the pre-flash is divided and metered, and the main flash is controlled based on the photometric value, the first mode in which the pre-flash is manually operated and shooting is started by the release operation And a second mode in which pre-emission is performed prior to the above. Partial dimming is performed in the first mode, and evaluation dimming is performed in the second mode. 2. The flash adjustment according to claim 1, wherein the partial light control in the first mode is performed based on a light measurement value obtained in a divided light measurement area corresponding to a selected focus detection point. Light system. 3. The evaluation dimming in the second mode is performed by dividing the distance measuring points selected by prioritizing the closest point among all the distance measuring points that may be selected. The strobe light control system according to claim 1, wherein the strobe light control system is performed based on a light measurement value obtained in a light measurement area. 4. A light metering device having a plurality of light metering regions, wherein at least one of the light metering regions divides and measures the reflected light by the pre-light emission, and a strobe for controlling the main light emission based on a light metering value from the light metering device. In a strobe light control system including a control means and an operating member for starting pre-emission, when the operating member is operated, pre-emission is performed in response to the operation and reflection by the pre-emission is performed. Light is measured in the divided metering area corresponding to the selected focus area, partial light control is performed, and if the release operation is performed without operating the operation members, the pre-shooting is performed prior to the start of shooting. In addition to performing light emission, the reflected light from this pre-emission is assigned to each divided photometry area by weighting the distance measurement point selected by the closest point priority among all the distance measurement points that may be selected. Metering, flash exposure system characterized in that a dimming control unit for performing evaluation photometry.