JPH03235929A - Stroboscopic device controller - Google Patents

Abstract

PURPOSE:To preclude short-distance overexposure at the time of stroboscopic photographing by fixing an aperture value, calculating the guide number of a stroboscopic device, and controlling its lighting time when the aperture value is smaller than a specific value. CONSTITUTION:When a film sensitivity detecting means 3 detects film sensitiv ity, a film sensitivity information (Sv) value calculating means 4 calculates an Sv value. A subject distance information (Dv) value arithmetic means 6 calculates a Dv value according to range finding data outputted by a range finding means 5. When data GVM stored in a storage means for the guide number (Gv) of the stroboscopic device almost in the full lighting state and two data on the Sv value and Dv value are inputted to an Avx (=GVM+Sv-Dv) decision means 7 first, this decision means 7 decides whether or not the aperture value Avx is larger than the specific value. Then when the aperture value is larger than the specific value, full lighting is performed and when the aperture value is smaller than the specific value, the aperture value is fixed and the lighting time of the stroboscopic device is controlled. Consequently, photographs with proper exposure are taken even at the time of short-distance photographing or when a high-ISO film is used.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is a strobe control device, and more specifically, it prevents overexposure when photographing a subject at a close distance with a strobe light, and also deepens the depth of field at a close distance. This invention relates to a strobe control device that appropriately controls exposure.

[Prior Art] As is well known, exposure control during strobe light shooting in a lens-shutter camera such as a compact camera requires
Generally, an automatic exposure control method called a flashmatic method is used in which the guide number (hereinafter abbreviated as GNo) is a constant value (GNo at approximately full flash) (Japanese Patent Laid-Open No. 1-239537, patent application Hei 1-1195
(See No. 27). This flashmatic (hereinafter abbreviated as FM) method is based on the fact that the guide number, that is, the product of the aperture and the irradiation distance, is constant, and the strobe guide number is measured using a distance measuring means within the camera. The aperture value (hereinafter referred to as FNo) of the lens is controlled using the subject distance (hereinafter referred to as D [m]) based on distance measurement information obtained by the camera, to obtain appropriate exposure. That is, the diaphragm is controlled by determining the FNo from the following formula. Here, S: Film ISO sensitivity 5 (100): Film sensitivity E at l5O100
■ Exposure value Av Averture value Tv Time value Bv Brightness value (Luminance value) Sv ASA (], SO) Speed value; Represents the exposure amount; Represents II”NO of the lens; Represents the effective exposure time of the shutter; Represents the brightness of the subject; represents the sensitivity of the film. Each of the above items is expressed by the following formula.

becomes.

Next, a design FMv diagram when this FM method is used will be explained with reference to FIG. 11. As a method of determining proper exposure using external light (light other than strobe light), the Apex method formula shown below is generally used: E v - A v + T
v −B v 10 S v is used. Here, Sv2,, eOg2N-8; film ISO sensitivity. However, 5=ioo and Sv = 5 (N=-0, 32) (K, N are exposure constants determined by the camera). Suppose that it is represented by the Ev diagram shown in FIG. The relationship between the Av value and the Tv value is determined by the thick line ■ in the center of Figure 11 above, and the relationship between the Sv value and the B
It is determined based on the Ev value corresponding to the v value. That is, Bv-5
, 5v-5, then EV -5+ 5 = 1.0, and from the intersection of the equal Ev line of E v -1,0 and the thick line ■, control is made with A v -4,5 and T v -5,5. Sarel.

Next, the case where a strobe is used will be explained.

In this camera, it is assumed that the flash matic light emitting point is interlocked with the effective exposure time of the shutter between 1/100 and 11500, which indicates the γ conversion point. When this is converted into an Av value, it becomes 4.5≦Av≦6.7. By squaring both sides of the above equation (1), taking the logarithm, and rearranging, we obtain. Here, if we set Gv -41og2 GNO2 Dv-90g2D2, we get Gv-Av+Dv-5v+5-(3). In this camera, the GNO only emits full light (GNO14), so the Gv value at this time is set to GvM (-7, 8). Furthermore, since 15O400 films tend to be commonly used, 15O400, that is, 5v-7 is substituted into the above equation (3) to obtain GvMm=AV+DV-7+5. Therefore, Dv-GvM-AV+2 = 7.6 -AV+2 = 9.8 -Av (4) Since the interlocking range of Av value is 4.5≦Av≦6.7, the interlocking of Dv value When formula (4) is substituted into the above formula, the range becomes 3.1≦Dv≦5.1. Therefore, in the FM diagram (G No. -14 constant), it is appropriate in area A, but over in area A (closer than -about 3 m), and under in area A (farther than - about 6 m).

As described above, the exposure control method used in conventional lens-shutter cameras has the disadvantage that it tends to overshoot at close range. As the quality of high-speed films improves, the frequency of use of high-speed films tends to increase, so the above-mentioned drawbacks can be said to be a major problem.

In this case, there is a way to prevent overexposure by directly metering the strobe light and stopping the light emission when the required amount of light is reached, but this means cannot determine the light emission timing. That is, it only controls the amount of light emitted when the aperture is constant. Therefore, the range of interlocking is
This will be limited to the range covered by direct metering.

[Problems to be Solved by the Invention] As mentioned above, in the conventional technical means of this type, a camera that employs a lens shutter such as a compact camera is exposed using the FM method using a film with high ISO sensitivity. During control, proper exposure is achieved in area A in FIG. 11, but overexposure occurs in area A on the short distance side.

Therefore, with means that directly measures the strobe light and stops emitting light when the required amount of light is reached, it is only possible to control the amount of light emitted at a fixed aperture value.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a flash control device that prevents short-range overexposure during flash photography, which is unavoidable with conventional flashmatic control, and allows proper exposure.

[Means for Solving the Problems] A strobe control device of the present invention includes a subject distance information output means for outputting subject distance information, a film sensitivity information output means for outputting film sensitivity information, and an output for outputting the guide number. a calculation means for calculating an aperture value by calculating Gv+5v-Dv from the guide number Gv, the film sensitivity information Sv, and the subject distance information Dv, and comparing the aperture value with a predetermined value. a comparison means; when the aperture value is larger than a predetermined value, the light is emitted at full power, and when the aperture value is smaller than the predetermined value, the aperture value is fixed and the aperture value is fixed, and the The present invention is characterized by comprising a light emission time control means for calculating a guide number of the strobe light and controlling the light emission time of the strobe light so that the guide number is set to the guide number.

[Function] This strobe control device uses a strobe device whose light emission time can be varied, and performs control along an F M v diagram as shown in FIG. 2. That is, when the subject exists at the distance of area A which is close and exceeded in Fig. 11 showing the conventional example, the light emission time is shortened and the GNo of the light emission is made small to control the area as shown in Fig. 2. .

[Example] Hereinafter, the present invention will be specifically explained with reference to illustrated embodiments.

FIG. 1 is a block diagram of a strobe control device showing one embodiment of the present invention, and FIG. 2 is an FMv diagram for its design. In the figure, when the film sensitivity is detected by the film sensitivity detection means 3, the Sv value calculation means 4
A v value is calculated. Further, the Dv value is calculated by the Dv value calculating means 6 based on the distance measurement data outputted by the distance measuring means 5. The data GvM stored by the storage means 2 of the Gv value of approximately full light emission, the above-mentioned Sv value, and the three data of the Dv value are first A vx (-G VM + S vDv
) When input to the determining means 7, the determining means 7 determines whether or not the aperture value Avx is larger than a predetermined value.

When the aperture value Avx is larger than a predetermined value, it is determined that the aperture value is in the area E as shown in FIG. 2, and when it is smaller, it is determined that it is in the area O. Further, the above three data GVM'Sv and Dv are also input to the light emission timing calculation means 8. This calculating means 8 calculates the light emission timing when the area O or the force is 0, that is, when substantially full light is emitted, from G VM, S v and D v. The calculation result is stored in the calculated light emission timing storage means 10, and the substantially full light emission time or substantially full light emission time storage means 11 is stored. These two storage means 10.11
A combination of these is the first light emission control data storage means 12, in which light emission control data for areas O and OFF are stored.

Further, the above two data Dv and Sv are input to the light emission time calculation means 9. This calculation means 9 calculates the light emission time during area work, that is, the predetermined light emission timing (A in FIG. 2).
Calculate the luminescence time when v=6.7, Tv=4),
The result is stored in the light emission time storage means 14 based on the calculation. A predetermined light emission timing is stored in a predetermined light emission timing storage means 13, and a combination of the above two storage means 13 and 14 or a second light emission control data storage sub-actor 15 stores light emission control data at the time of area engineering. be done.

These first. The data output from the second light emission control data storage means 1215 is inputted into the selection means 16, and the data selected by the Avx determination means 7 is outputted to the light emission control means 17, whereby the strobe device 18 The light emission timing and light emission time of the light are controlled.

In this way, in region O, power, that is, on the far side, the light is emitted at full capacity, and the FNo at the time of light emission is controlled.

On the other hand, in the field work, that is, on the short distance side, the FNo at the time of light emission is fixed, and the light emission time is controlled. As a result, the range in which the strobes are interlocked is the sum of the amount of light emission control and the FNo control, resulting in interlocking over a wide range.

The strobe control device 1 of the present invention is constituted by the above 2 to 18 means and devices.

Next, the operation of this embodiment configured as described above will be explained with reference to timing charts and flowcharts shown in FIG. 3 and subsequent figures. Figure 3 shows the timing chart of a series of camera operations after release, and Figure 4 shows the flow after release "RE".
In Fig. 4, when the No. 1 Lurise button is pressed, the program "REL" is executed.First, distance measurement 2 and photometry are performed (step S1), and the lens is extended to focus. Step S2) calculates the D v (=jl' 0g2 D2 ) value from the distance measurement data D (Step S3), and calculates the Sv value by reading the DX code of the film (Step S4). Then, the exposure amount Ev is determined from the photometric value Bv and the film sensitivity Sv (step S5), and the seconds are calculated based on this Ev value (step S6).The processing of steps 81 to S6 is shown in FIG. Compatible with distance measurement and photometry 1-second calculation ■.

Next, steps 87 to S27 are added corresponding to charging voltage check and light emission judgment (3) shown in the time chart of FIG.
Steps 87-S21 for determining whether to emit light (○) and steps 822-S for calculating light-emission timing and light-emission time (O)
It consists of 27. This camera has four strobe modes: forced flash mode, strobe off mode, red-eye reduction mode, and normal mode. Further, the light emission flag is a flag that is 1 when the main light is emitted and is 0 when the main light is not emitted, and the pre-emission flag is a flag that is 1 when the pre-emission is performed and 0 when the main light is not emitted.

In step O consisting of steps 87 to S21 in FIG. 4, light emission is determined and determined as shown in Table 1 below.

4. In other words, when in normal mode or red-eye reduction mode, if the time determined from the Ev value is faster than the camera shake time (the time at which camera shake is more likely to occur, which is the reciprocal of the normal focal length), and the camera is in direct sunlight, set the flash flag to 0. If the charging voltage is 260 V or higher in backlighting, the light emission flag is set to 1, and when the red eye reduction mode is in effect, the blurring light emission flag is set to 1. When the speed is low, the seconds are rounded to the seconds corresponding to camera shake (step 514). If the charging voltage is 260V or more, the light emission flag is set to -1, and when the red eye reduction mode is set, the pre-light emission flag is set to -1. If it is the forced light emission mode, it is judged based on the charging voltage, and if it is 260cm or more, the light emission flag is set to 1. In the strobe off mode, the light emission flag remains at 0.

Moving on to FIG. 4(B), in step 0 consisting of steps 822 to S27, the light emission timing and light emission time are calculated, which is the key point of the present invention.

The details of the calculation will be described later, so the flow will be briefly explained here. First (aperture value) A vx (= G VM +
FMv in FIG.
Use the diagram to determine whether the area of light emission is in area O, force, or area.

If Avx is greater than a predetermined value (area O, force), that is, on the long distance side, the light emission timing is calculated from GyM, Sv, and Dv (step 524), thereby executing aperture control. At this time, the light emission time is set to approximately the full light emission time (step 525). If the aperture value Avx is less than a predetermined value (region adjustment), that is, on the short distance side, after setting the light emission timing to the predetermined light emission timing (step 526), the light emission time is calculated from Sv and Dv (step 527). Execute GNo control.

Next, in step 828, the lens is extended. Then, during the period (2) of steps S29 to S31, the display process is performed while waiting until the second release is turned on (steps S29, S30, 531). During this waiting period, if the second release is off (step 53
1) Then, it becomes 7 HALT and becomes standby state.

When the process returns to step S29 and the second release is turned on, the process proceeds to step 3, which consists of steps 332 to S37 (only in the red-eye reduction mode).

That is, the pre-emission flag is checked (step 532), and if the pre-emission flag is 1, the pre-emission flag is checked every 50m5 (step 537).
), pre-light emission (step 534) is performed (N+1) times (step S35.536). Note that in this embodiment, N-
11 (step 833). Due to this brilliance,
The pupil of the subject's eye is made smaller to prevent the red-eye phenomenon from occurring, but the prevention of red-eye caused by this blurred light is disclosed in Japanese Patent Application No. 63-31161 filed earlier by the present applicant.
Since it is described in detail in No. 9, the explanation here will be omitted. Further, the subroutine "bright light emission" in step S34 will be explained later with reference to FIG. 8.

In the exposure ■ of step 938, subroutine "5"
Exposure operation is performed by "HUTR".

This subroutine "5HUTR"' will be explained in detail with reference to FIGS. 5 and 6 below. Next, step S39 1
After performing frame winding (2), lens reset (2) in step S40 is executed, and the camera becomes "HALT" and enters a standby state. It is assumed that this "HALT" is released by the second release, the mode change switch, or the like.

Next, the subroutine "5HUTR" showing the exposure operation of step 83g in FIG. 4 will be explained with reference to FIG. 5 showing its operation timing and FIG. 6 showing the flow. In FIG. 6, first, the magnet is energized (step 551) and the motor is turned on (step 552). Then, it waits until the switch AESW, which detects the timing when the shutter opens, is turned off (step 553).
, waits for the time from when the AESW is turned off until the shutter actually opens (step 554). Here, the time Ts after the shutter starts opening shown in FIG.

For T o + T p, Ts is the time in seconds until Mg is turned off, To is the time until it is released, T is the time until light emission, and TFL is the light emission time.

F''9 As shown in Fig. 6, after waiting the AETRG time from the AESW off, the second timer (Ts dark time timer)
Time timer until release (T.

timer) and the time until light emission (Tp timer) are started (steps 855 to 55).
7). After that, step S58. The three judgments shown in S64 and S66, that is, whether the seconds have come (step 558)
, whether the time until opening has arrived (step 564), and whether it has reached the time to emit light (step 566) are each executed in parallel.

Time Ts, T after the shutter starts opening shown in FIG.
Which of o and TF comes first depends on the calculation result, but the region where the aperture value changes according to the aperture of the shutter blades, that is, the region where the shutter aperture waveform shown in Fig. 5 is a triangle represented by the upward-sloping straight line Ω1 Consider a case where strobe light is emitted in an aperture region and the time Ts until Mg is turned off is longer than the time To until the opening. In that case, it is time for the light to emit at the beginning (
Step 566), if the light emission flag is 1 (Step 0 S67), subroutine “F” is executed, which will be explained later in FIG.
LUSH'' (step 562) performs main light emission.

Next, it is time to release (step 564) and the motor is braked (step 863).

・Furthermore, the time in seconds to turn off Mg is reached (step 8).
58), the magnet is turned off (step 559), and the shutter is closed. Here, the light emission flag is 1 (step 56
0) However, if the light has already been emitted (step 561), the main light emission in "FLUSH" (step 562) is not performed, and the motor is braked (step 863).
)do. A case where the times of the three timers are reversed can also be easily considered using the flow shown in FIG. 6, so the explanation here will be omitted.

FIG. 7 is a flowchart showing details of the subroutine "FLUSH" of step S62 in FIG. 6 above. As shown in the figure, this subroutine 'FLUSH' uses a light emitting time timer to calculate the light emitting time T pt, (see Fig. 5).
The main light is emitted only during this period.

FIG. 8 is a flowchart showing details of the subroutine "pre-emission" in step S341 in FIG.
Pre-light emission for red-eye prevention is performed only for 2 μs.

Here, a case will be described in which the actual shutter time is determined from the relationship between the exposure value Ev and the apex-calculated time. If the second time to be determined is Ts, then in the triangular area, the shaded area shown in FIG. -2Ev. This 2-8v is rearranged by taking the logarithm of both sides from Figure 9 (A), Ev = Jog2Fo -2・, 6og2Ts + -6
og2To-1 (6)

From the apex calculation conversion formula, if the aperture value is Av and the open Av value is Avo, then A vo = (log2F o 2-・-------
−(7).

Further, if the shirt time in seconds is Tv, and the Tv value of 1/2 of the seconds is Tvs, then the following equation is obtained.

Further, if the Tv value at 1/2 of the time until opening is Tvo, it can be expressed as follows.

2 becomes.

Substituting these into the above equation (6), Tvs= 1 / 2 (E v - Avo + Tvo)
...---(8) T s -2"-Tv'
−・”(9) are obtained, respectively.

3 On the other hand, in the trapezoidal region, it can be expressed as follows from the area -2Ev of the hatched part shown in FIG. 9(B).

If we take the logarithm of both sides and rearrange, the value EvSFT is stored in a storage means such as an E2PROM, and each correction is made at the time of calculation.

Based on the above, calculation of seconds is performed as follows.

becomes.

Substituting the above equation (7) into this equation, T vs −E v −A vo −−(
10) Ts -1/2 (2(1-TvS)+To)
=(11) are obtained respectively.

Since the triangular area and the trapezoidal area are continuous, the exposure value E at the γ conversion point
v can be obtained by eliminating Tvs from the above equations (8) and (10). That is, in the case of this embodiment, the value TvSFT is used to correct the Tv value up to maximum aperture, and the exposure value Ev is corrected. If the value is darker or brighter than the designed value, a value called EvSFT is written in the E2RPOM to correct it during adjustment at the factory.

5 Next, the FM system of the present invention will be explained with reference to FIGS. 2 and 10. The FMv diagram is shown in Figure 2, and the low IS
When using O-sensitivity film or when the subject is far away, use full flash at maximum aperture. That is, it is the area force in FIG.

At short distances or at a high ISO, the flash remains at full power, but the flash point changes and fires before the aperture is fully opened. That is, this is area O in FIG. If the shutter is close to opening, a slight deviation in the light emission timing will not have much effect on the number of aperture steps Av, but when the aperture is closed down, a small deviation in the light emission timing will greatly affect the number of aperture steps Av.

Generally, the aperture speed and aperture timing change depending on mechanical errors in the shutter itself, battery voltage, temperature, etc., so performing FM control with a large aperture will lead to an increase in exposure error. Therefore, in this example, the shutter speed is 11500.
Up to this point, you can change the light emitting point to narrow down the focus, but you cannot make the light emit any faster than that.

Furthermore, at short distances or at high ISO, the flash time of the strobe 0 is shortened, which increases the GN/GN of the strobe.
Proper exposure is achieved by reducing o. In other words, this is the area construction in FIG.

In FIG. 2, only the F M v diagram of 15O400 is shown, but the same applies to films with other ISO speeds.

Next, regarding the calculation method of the FM method of this embodiment, FNo.
(3) above to optimize exposure by strobe light by performing two-stage control of control and GNo control.
We are trying to expand the area that satisfies the formula. First, determine whether it is area engineering, area o, or force in Figure 2. In FIG. 2, the switching point is Av=8.7 Tv-9 (seconds -17500), and the Av value at this switching point.

The Tv value varies depending on the characteristics of the camera, so each A
vp, Tvp. Also, the Gv value at full flash is G
v-, so by substituting these into equation (3), we get G VM-A
vp + D v S v + 5. If the above equation is rearranged, it becomes 7 G VM + S v D v - A vp +5. Therefore, the determination of the area is as follows.

When the charging voltage of the strobe is sufficiently high to emit substantially full light, the above formula (14) may be used, but in reality, the charging voltage may be low and the strobe may not emit substantially full light. Therefore, in this embodiment, in order to give priority to the release timing, at the time of release, if the battery is not fully charged, charging is not performed again to fully charge the battery. Instead, when the charging voltage is low, the battery is not fully charged. The Gv value at full light emission at voltage is replaced by GVM in equation (14). This value Gv may be determined directly from the charging voltage, or may be obtained by subtracting a correction value according to the charging voltage from GvM. Since this correction value is uniquely determined by the characteristics of the strobe device, it can be easily corrected if you have a table of charging voltages and correction values. Here, the charging voltage correction value is set to A1.

Also, in red-eye reduction mode, when firing the strobe,
Prior to the main flash, a pre-flash is performed to reduce red-eye. If you check the charging voltage again after this pre-flash,
If the charging voltage can be corrected using the charging voltage correction value A1, or if the charging voltage is checked only before the pre-emission, it is necessary to correct the decrease in the Gv value due to the pre-emission. This correction value can also be easily corrected by having a table of charging voltages and correction values.

Here, the red eye correction value is set to A2. That is, the Gv value at full flash of main flash is Gv - G - Charging voltage correction value A - Red eye correction value A2VM
It becomes l. Therefore, in the case of this camera, the above equation (14) has zoom ranges from wide to tele and macro as shown in FIG. 2, and the Av value of the function differs depending on the zoom. Also, the switching point for FNo and GNo is not the Av value, but Tv-4 (seconds -11500
) is determined. Therefore, the fixed value Avp+ of equation (15)
5 is a table based on Tv values.

Substituting this equation (16) into the above equation (15), taking the logarithm of both sides, Aog2Fp = I3og2To - 0g2Tp 10! 0
g2FO2 where Tvo -1-(log2T.

Tvp=1 (l 0g2Tp Avo-10g2F02 Avp-fl　0g2F　p2 By substituting into the above formula, we get Avp=-Tvo+Tvp+Av.

-Tvp-Tvo+Av.

・・・・・・・・・(16) becomes 0. In this camera, TvO and Avo change depending on the zoom value, but Tvp is fixed at 4. Of course, the same applies even if this value changes due to zooming.

Next, calculation is performed for each area. First, in area O and power, full light is emitted, and what is needed is the light emission timing. (16
), replace Tvp with TvF and calculate the time until light emission using G - charging voltage correction value A1 M blurry light emission correction value A2 + 5v - Dv 1 . If this time is longer than the opening time, it goes without saying that it is rounded up to the opening time.

On the other hand, in area engineering, the light emission timing is Tp, and the light emission time is determined. First, considering the case where the battery is sufficiently charged, GvMGGvF (Gv value at the time of light emission) is calculated using equation (16°), and excluding the correction value, GVF-D v -S v + Tvp - Tvo+
It becomes Avo+5. The light emitting time at which GvF is reached is determined by the charging voltage and whether or not pre-emission is performed. Ideally, there should be a relational expression between Gv and light emission time depending on the charging voltage and the presence or absence of pre-light emission, or there should be a table of GVP and light emission time for each charging voltage and presence or absence of pre-light emission. To actually do this would require complicated calculations and a huge amount of ROM data. Therefore, in this embodiment, only one table is provided for the Gv value and luminescence time at full charge, and when the charging voltage is low, the charging voltage correction value (charging voltage correction B1) is added to the required Gv value. Furthermore, when performing pre-flash, add the pre-flash correction value (pre-flash correction B2) GvF = Dv-8v + Tvp-T
vo+Avo+5+charging voltage correction B+pre-emission correction correction (17) is obtained, and the light emission time is obtained by referring to the table from GVP'.

In both cases of FNo control and GNo control,
Since the light emission timing is meaningless if it is later than the shutter time, in that case, the light emission timing is set to the shirt time. That is, if T ≧Ts then Tp4-TS If this is the Tv value, if T ≦Tvs then TVF←TvS■F Also, in this case, based on this timing, the light emission time is
I need to search again. In equation (17), Tvp−T
As vs, 3 GvF -Dv-Sv+Tvs-Tvo ten Avo+5+
Charge voltage correction B1+pre-light emission correction B2 is determined, and the light emission time is determined from this GVF' by referring to a table.

GVF -Dv-Sv+Tvs-Tvo+Avo+5+
Charge voltage correction B + pre-light emission correction correction light emission timing -Ts The FM control of this embodiment is performed by the above calculation.

Generally, as the flash time of a strobe becomes shorter, the Gv value decreases more due to a decrease in charging voltage. Therefore, it is not appropriate to correct the charging voltage correction B1 and the blurring correction B2 simply by using the charging voltage. Therefore, in this embodiment, a correction value is obtained using a matrix of required Gv and charging voltage. As a result, even with only one table of Gv values and light emission times, highly accurate FM control can be achieved.

Summarizing the above, FM performance is performed as follows.

4 1) Judgment of area: Avx≧N...Control area of FNo Avx<N...Control area of GNo However, A
vx-G - Charging voltage correction value A1 - M - Emission correction value A 2 + S v D vN - Tvp
-Tvo+Avo+5 2) FNo control area: Light emission time - Time light emission timing of full light emission -2 (l T vp) T -G
-Charging voltage correction value A1 VF VM Bright light correction value A2 + S v- D v + Tvo-Avo-5 However, if it is later than the opening timing, the opening timing is used.

3) GNo control area: Obtained from light emission time - GvF' (Gv value 1 light emission time) with reference to the table.

G vp - D v S v + T Vp
T VO + A VO 15 + Charging voltage correction Bl + Bright light emission correction B2 Light emission timing - Tp Tp - 2 (1 - Tvp) 5 4) In 2) and 3) above, when TvF≦Tvs, from light emission time - Gvp' (Gv value (2) Luminescence time) Determine by referring to the table.

[Effects of the Invention] As described above, according to the present invention, it is now possible to easily take photographs with proper exposure even when taking short-distance shots or using high ISO film, where conventional strobe photography results in large overexposure. It has a remarkable effect of becoming.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram of a strobe control device showing an embodiment of the present invention, FIG. 2 is a design FMv diagram in FIG. 1, and FIGS. 3 and 4 (A), (B) ) are a timing chart and a flowchart of a series of camera operations after release in the camera to which this embodiment is applied, and FIGS. 5 and 6 are a timing chart and a flowchart of the exposure operation in FIG. 3.4 above, and FIG. 7 is a flowchart showing details of subroutine 6 "FLUSH" in FIG. 6, FIG. 8 is a flowchart showing details of subroutine "FLUSH" in FIG. 4, and FIGS. 9(A) and (B) ) and Figures 10 (A) and (B) are characteristic diagrams for calculating the exposure amount from the exposure value and exposure time, and Figure 11 is a design F for a camera with a conventional strobe control device. It is an Mv diagram. 1... Strobe control device 3...
. . . Film sensitivity detection means (film sensitivity information output means) 4 . . . Sv value calculation means (film sensitivity information output means) 5 . . . l1l11 Distance means (subject distance Information output means) 6...Dv value calculation means (subject distance information output means) 7...Avx determination means (calculation means for determining aperture value) 12... ...First light emission control data storage means (light emission time control means) 7 5... Second light emission control data storage means (light emission time control means) 16... Selection means (comparison means and luminescence time control means)

Claims (1)

[Claims] (1) Subject distance information output means for outputting subject distance information, film sensitivity information output means for outputting film sensitivity information, output means for outputting the guide number, strobe guide number Gv, and the film sensitivity information From Sv and the subject distance information Dv, Gv+Sv-
a calculation means for calculating an aperture value by calculating Dv; a comparison means for comparing the aperture value with a predetermined value; If the aperture value is smaller than that, the aperture value is fixed and a guide number of the strobe is calculated from the film sensitivity information and subject distance information, and the flash time of the strobe is controlled so that the guide number is reached. A strobe control device comprising a control means.