JPH01200242A - Flash light photographing device - Google Patents

Abstract

PURPOSE:To use a film having higher sensitivity than the limit of a high sensitivity side fixed by the error of exposure in a telezoom state by forcedly changing the telezoom state of a light emission part to a wide zoom state when the sensitivity of the film is equal to or exceeding a specified value. CONSTITUTION:When the read sensitivity of the film is equal to or exceeding the specified value, the light emitting part 101 is forcedly changed from the telezoom state to the wide zoom state by a control means 104 and a change means 102 so as to perform flash light photographing. By appropriately selecting and changing the state of the light emission part 101, the film having high sensitivity than the limit of the high sensitivity side fixed by the error of exposure in the telezoom state is used to perform flash light photographing.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a flash photographing device having a light emitting section whose irradiation angle can be changed to vary the irradiation intensity.

B. Conventional technology An electronic flash device has an automatic light control device that stops emitting light when a desired amount of light is irradiated onto the subject from a flash discharge tube, which is a light emitting unit, and has a light emission time characteristic shown in Fig. 7. have. Point 0 in the diagram. The curves indicated by P and E represent the characteristics when full light is emitted, and the amount of light emitted is .

This point is 0. It is indicated by the area surrounded by P and E.

When stopping light emission at a predetermined amount of light emission, for example, when issuing a command to stop light emission at time A, ideally the amount of light emission should be at point ○.
, P, S, and A. However, with current automatic light control devices,
The response characteristics of the amplifier that amplifies the output from the light-receiving element, the response delay of the flash discharge tube from when the light emission stop command is issued until the light emission actually stops, and the electrical Response delay or in parallel control, the response delay due to the leakage of light emission until the current flows to the quench tube affects the points ○, P, and ST.

The light emission is indicated by SE. In other words, points A and S.

An error occurs in the amount of light emitted by the area surrounded by ST and SE.

Furthermore, the above-mentioned error in the amount of light emission also occurs depending on the light adjustment timing of the automatic light control device, that is, the amount of light.

For example, the amount of light necessary to obtain the appropriate amount of exposure is shown at point 0 in FIG. When the amount of light is large as shown by the area surrounded by P, S, and A, points A and S in Fig. 7 are
, ST, and SE, the ratio of the dimming error is not so large. However, if the light amount necessary to obtain the appropriate exposure amount is small as shown by the area surrounded by points O7S' and A', then points A I ,
S l.

The ratio of the dimming error, which is the area of the portion surrounded by ST' and SE', increases.

In this way, with automatic flash control devices, there is always an error in the amount of light emitted when the flash stops, and the effect that this error in the amount of light emitted has on film exposure varies depending on the following shooting conditions.
The shorter the shooting distance, ■The larger the aperture diameter, and ■The higher the film sensitivity, the greater the effect. This point will be explained below.

FIG. 8 shows the flash light control characteristics at each camera-side aperture value. In the figure, the vertical axis shows the aperture value in steps of one stop, the horizontal axis shows the shooting distance, and the bar line in the figure, for example f2 (
T) represents the amount of light adjustment at the aperture 2. Therefore, the vertical distance of f2(T) with respect to the horizontal axis of f2 is the exposure error of the film caused by the light adjustment error, and there is no error at a shooting distance of 6 m, and an error of less than 1 stop at a shooting distance of 2 m, resulting in overexposure. It's becoming a trend.

In this way, the film exposure error due to automatic light control is
The shorter the shooting distance, the greater the value. Further, as is clear from FIG. 8, the larger the aperture diameter, the larger the exposure amount error. These phenomena occur because: ■The shorter the shooting distance and the larger the aperture diameter, the larger the amount of the error in the amount of light emitted shown in Figure 7 that is guided to the film surface; This is explained by the fact that when the aperture diameter is large or the aperture diameter is large, the above-mentioned light adjustment timing is advanced and the light emission amount error ratio becomes significant, which increases the influence on the film exposure amount error.

FIG. 9 shows the flash dimming characteristics when using a film that is two steps more sensitive than FIG. 8. In this case, as the sensitivity of the film increases, the error in the amount of light emitted has a greater influence on the error in the exposure amount of the film.

For example, when looking at the bar line f2(T) in FIG. 9, an exposure amount error of one step occurs at about 4 m on the short distance chick side. The reason for this is that if the film sensitivity is high, the light emission error shown in Figure 7 will be more sensitively perceived as the exposure amount by the increased film sensitivity, which will further accelerate the above-mentioned flash control timing and the light emission amount. This is because the error ratio becomes significant. In addition, Fig. 10 shows the dimming characteristics when using a film with one step higher sensitivity than Fig. 9, and shows f2(T
), an exposure error of one step or more occurs when the shooting distance is 1i6 m or less, and the exposure error of the film increases. Note that in normal flash photography, the allowable exposure error that can be considered as proper photography is ±1 step, so the film sensitivity shown in FIG. 9 is the high-sensitivity limit of the film used.

On the other hand, electronic flash devices (hereinafter referred to as zoom flash devices) have been known that have an automatic light adjustment device and whose irradiation angle is variable according to the focal length of a lens attached to a camera. This zoom flash device normally uses a diffuser plate to change the degree of diffusion of the flash light while the amount of light emitted by the flash discharge tube remains constant.Generally, it irradiates light over a wide range. In a so-called wide zoom state, the light emission intensity is low, and in a so-called telezoom state, in which light is locally irradiated, the light emission intensity is higher than in the wide zoom state.

The flash light control characteristics in this zoom flash device are different between the wide zoom state and the telezoom state. That is, in FIG. 9, the solid line (T) indicates the telezoom state, and the broken line (W) indicates the wide zoom state, and the exposure amount error in the wide zoom state is lower than that in the telezoom state. This is due to the difference in light emission intensity between the wide zoom state and the telezoom state. Therefore, in the wide zoom state, the light corresponding to the light emission amount error when the light emission is stopped, that is, the light corresponding to the dimming error, reaches the film at a reduced level compared to that in the telezoom state, so that the film exposure amount error is also reduced. In other words, it can be seen that in the zoom flash device, the high sensitivity limit of the film used is determined by the exposure amount error in the telezoom state.

Problems that C0 invention attempts to solve In this way, in the zoom flash device.

Since the exposure amount error in the tele zoom state (state where the light emission intensity is high) determines the high sensitivity limit of the film used, even if a higher sensitivity film can be used in the wide zoom state (state where the light emission intensity is low). There was an absurdity in that the high-sensitivity film could not be used in the telezoom state (state where the luminous intensity was high).

An object of the present invention is to enable the use of films with higher sensitivity than the high-sensitivity limit of the film used, which is determined by the exposure amount error in the telezoom state (state with high emission intensity).
An object of the present invention is to provide an automatic light control device having an easy-to-use illumination angle switching type light emitting section.

Means for Solving Problem D1 To explain with reference to FIGS. 1(a) and 1(b), which are diagrams corresponding to claims, the present invention includes a light emitting unit 101 that illuminates a subject,
A changing means 102 that can change the illumination angle between a wide zoom state where the illumination angle of the light emitting unit 101 is wide and a telezoom state where the illumination angle is narrow; The present invention is applied to a flash photography device having an automatic light control means 103 that stops emitting light when the light intensity level reaches . According to the apparatus of claim 1, the above-mentioned problem is solved as shown in FIG.
This problem is solved by having a control means 104 that controls the changing means 102 to forcibly change the light emitting section 101 to the wide zoom state when the read film sensitivity is higher than a predetermined value when the camera 1 is in the tele zoom state. be done.

Further, according to the device of claim 2, as shown in FIG. Displaying a warning when it is detected that the means 102 is in the telezoom state and the read film sensitivity is higher than a predetermined value;
Further, the above-mentioned problem is solved by including the display control means 105 which detects that the change means 102 changes from the tele zoom state to the wide zoom state and cancels the warning display.

Further, as in claims 3 and 4, a sensitivity detection means for detecting film sensitivity, a distance detection means for detecting distance information corresponding to a distance to a subject, and an aperture detection means for detecting an aperture value of a photographic lens. The control means may control the changing means to the wide zoom state only when the exposure amount error determined by the film sensitivity, distance information, and aperture value is equal to or greater than a predetermined value.

In the flash photographing device according to claim 1, the light emitting section 101 is forced into a low wide zoom state when the film sensitivity is higher than a predetermined value, thereby making it possible to use a film with higher sensitivity. Further, in the second aspect of the present invention, a warning is displayed when a film sensitivity of a predetermined value or more is read in the tele zoom state, and the warning is canceled when the wide zoom state is entered.

F. Example (1) Structure of Example (a) Light-emitting unit Figures 2 and 3 are perspective views of the light-emitting unit in the up position (light-emitting part exposed position), and are in the wide zoom state and telezoom state, respectively. It shows the condition.

The case 10 consists of a pair of left and right base parts 12 through which a rotating shaft 11 is provided, and a cylindrical body 13 with a rectangular cross section extending from the base parts 12 in front of the camera.The rotating shaft 11 is connected to the camera body (not shown). is rotatably supported. Further, a torsion coil spring 41 is wound around the rotating shaft 11, and an arm 41a of the spring 41 is attached to a pin 14 implanted in the case 10.
The arms 41b are respectively hooked to pins 15 provided on the camera body (not shown), and the case 10 is biased in the clockwise direction C by the spring force. The rotation of the case 10 in the clockwise direction C is restricted by the end portion 12a of the case 10 coming into contact with a restriction pin 42 implanted in the camera body (not shown).

The light emitting unit 16 is screwed onto the inner wall of the cylinder 13 so as to be surrounded by a protector 17 that moves back and forth inside the cylinder 13 in the camera optical axis direction. A diffuser plate 17a is provided on the front side of the camera of the protector 17 to diffuse the irradiated light from the first light emitting section 16. A rack 17b is provided on the protector 17 and meshes with the gear 18. A gear 20 rotates together with the gear 18 by a shaft 19 and meshes with a gear 21. The gear 21 is fixed to the output shaft 22a of the motor 22. Note that the motor 22 and shaft 19 are supported by the case 10. By rotating the motor 22 forward and backward, the protector 17 moves back and forth in the camera optical axis direction via a gear train. As a result, the diffuser plate 17a and the light emitting part 16 are brought into contact with each other, and the light from the light emitting part 16 is emitted in a wide zoom state with a wide light distribution angle. It is possible to take a telezoom state in which the light is irradiated at a relatively narrow light distribution angle.

In order to detect the wide zoom state and the telezoom state, the barrel 13 is provided with a wide detection switch 23 and a telephoto detection switch 24.
The contracted end 17c of the protector 17 is the contact piece 23a.
, 23b, and the teledetection switch 24 is turned on by contacting the end portion 17d of the protector 17 that extends.
is turned on by bringing contact pieces 24a and 24b into contact.

Further, an up switch 25 that is turned on when the case 10 is in the up position is provided on the camera body side.

The up switch 25 is turned on when the end 12b of the case 10 contacts the contact pieces 25a and 25b in the up position.

Further, the case 10 is provided with a claw portion 13a at the bottom of the cylindrical body 13, and this claw portion 13a can engage with a claw member 43 provided on the camera body in the down position (light emitting unit storage position). An operating member 45 is integrally provided on the claw member 43 via a shaft 44 .

This shaft 44 is provided with a torsion coil spring 46, one end of which is hooked to the spring hook portion 43a of the claw member 43, and the other end hooked to a pin 47 implanted in the camera body (not shown). The claw member 43 is configured to be biased in the counterclockwise direction U by a torsion coil spring 46. Limit pin 48
is a restriction on rotation of the claw member 43 due to spring force, and a restriction pin 49 is a restriction on rotation in the clockwise direction by operation of the operating member 45. Now, move the operating member 45 to the index 45.
When turned in the direction of the arrow a, the claw member 43 rotates in the clockwise direction C against the force of the torsion recoil spring 46. However, the rotation is limited at the position where the claw member 43 comes into contact with the restriction pin 49.

(b) Electrical circuit diagram FIG. 4 is a control circuit block diagram of a camera with a built-in electronic flash device to which the present invention is applied.

In FIG. 4, a microcomputer 50 that controls sequential operations of the camera includes a release switch 51. Half-press switch 52. Up switch 25, tele detection switch 24. Wide detection switch 23. Signals are input from a film sensitivity reading circuit 55 and a focal length signal output circuit 56, respectively. Each switch and microcomputer 50
A pull-up resistor R is provided between each switch, so that the switch input of the microcomputer 50 becomes high level when each switch is turned off.

Here, the half-press switch 52 is turned on by the first stroke of the release button (not shown), and the release switch 51 is turned on by the first stroke of the release button (not shown).
is turned on by the second stroke of the release button. The telephoto detection switch 24 and the wide detection switch 23 are switches that are turned on when the light emitting unit is in the telezoom state and the wide zoom state, respectively, as described above. Further, the up switch 25 is a switch that is turned on when the light emitting unit is in the up position, as described above.

Further, the film sensitivity reading circuit 55 reads the film sensitivity from the signal pattern provided on the cartridge.
Alternatively, the manually input film sensitivity is read and a signal is sent to the microcomputer 50. A focal length signal output circuit 56 is provided in the interchangeable lens, and identifies whether the focal length of the attached lens is a telephoto type or a wide angle type, and sends information to the microcomputer 50.

The microcomputer 50 also includes a motor drive circuit 5.
7. A dimming control circuit 58 in the camera body is also connected, and each circuit is driven by an output signal from the microcomputer 50. The motor drive circuit 57 receives a motor drive signal and a signal indicating the rotation direction of the motor 22 from the microcomputer 50, and drives the motor 22. Film sensitivity information (hereinafter referred to as ISO information) is sent from the microcomputer 50 to the dimming control circuit 58.

The light control circuit 58 amplifies the output from a well-known TTL light receiving element 59 (hereinafter referred to as TTL light control SPD) during flash photography, integrates the value, and reaches a certain level. At this time, a light emission stop signal is sent to the light emission circuit 6o. Incidentally, the integration is started at the timing when the integration start switch 61 (hereinafter referred to as IS switch) is switched from the f terminal to the g terminal when the front curtain of the shutter (not shown) has completed running.

Further, in response to the Is switch 61 being switched to the g terminal, the light emitting circuit 60 causes the cannon tube 16a forming the light emitting section 16 to emit light. In the figure, 16b is a reflective umbrella, L
E is a photographic lens, and FI is a film. Further, 65 is a set aperture output circuit that outputs the set aperture to the microcomputer 50.

In the above configuration, the light emitting section 16 is connected to the light emitting section 101, the motor 20. Gear 18. Protector 17. The rack 17
b etc., the changing means 102, the light receiving element 59, the light control circuit 58, etc., the automatic light control means 103, the microcomputer 50, the control means 1042, the display control means 10, etc.
5 respectively. Further, the film sensitivity reading circuit 55 constitutes a film sensitivity reading circuit, the focal length signal output circuit 56 constitutes a distance detection means, and the set aperture output circuit 65 constitutes an aperture detection means.

(II) Operation of the embodiment When the release button (not shown) is pressed halfway, the halfway press switch 5
2 is turned on, and as a result, the power of the camera is turned on and the light emitting circuit 60 starts charging. The microcomputer 50 also receives focal length information of the attached lens from the focal length signal output circuit 56 and a signal indicating whether the case 10 is in the up position from the amplifier switch 25, as well as a telephoto detection switch 24 and a wide A signal indicating the current zooming position of the light emitting unit is input from the detection switch 23 . Furthermore, microcomputer 5
0 receives a film sensitivity signal from a film sensitivity reading circuit 55 based on a signal pattern provided in the cartridge. Based on these signals, the microcomputer 50
determines whether or not the motor 22 can be driven and the motor rotation direction, and sends a motor drive signal to the motor drive circuit 57.

Here, zooming control of the light emitting unit will be described in detail with reference to the motor control processing procedure shown in FIG.

First, in step S1, photographing information is read. Here, the shooting information refers to the initial state of the flash up switch 25. These include information on the telephoto detection switch 24 and wide detection switch 23, focal length information on the attached lens, and film sensitivity information. In the next step S2, it is determined whether the up switch 25 is on. If not turned on, step S3
Proceed to.

It is determined whether the wide detection switch 23 is on.

If it is on, the process returns to step S2 without doing anything, and if it is off, the process proceeds to step S4. That is, up switch 2
5 is off and the wide detection switch 23 is off when the light emitting unit is being moved from the up position to the down position, and the motor 22 is reversed in step S4.

The diffuser plate 17a is brought close to the light emitting section 16 to make the light emitting section unit into a small shape, that is, a wide zoom state. When the wide detection switch 23 is turned on in step S5, the motor 22 is stopped in step S6.

On the other hand, if the up switch 25 is on, step S2
The process then proceeds to step S7. In step S7, it is determined whether the sensitivity of the film loaded in the camera is higher or lower than a certain predetermined film sensitivity reference value Sv. If the sensitivity of the film used is lower than the reference value Sv, the process advances to step S8, and it is determined whether to enter the telezoom state based on the initial information regarding the attached lens. If it is determined that the telezoom state is to be entered, the process advances to step S9, and it is determined whether the telephoto detection switch 24 is on. If it is on, the light emitting unit is already in the telezoom state, so the process returns to step S2 without doing anything. If the telephoto detection switch 24 is off, the motor 22 is rotated forward in step SIO to bring the diffuser plate 17a close to the light emitting section 16. When it is detected in step S11 that the telephoto detection switch 24 is turned on, the motor 22 is stopped in step S12.

In addition, if it is determined in step S7 that the sensitivity of the film used is higher than the reference value Sv, then in step S3 described above,
→Same as S4→S5→S6, step S13→S14
→S15→S16, the light emitting unit always enters the wide zoom state.

If it is determined in step S8 that the tele zoom state is not to be established, the process proceeds to step S17, and it is determined whether or not the wide zoom state is to be established. If it is determined in step S17 that the wide zoom state should be established, step 318
At this point, it is determined whether the wide detection switch 23 is on or not. If it is on, the wide zoom state is already in effect, so the process returns to step S2 without doing anything. If the wide detection switch 23 is off, the motor 2
2, and in step S20 wide detection switch 2 is turned on.
3 is detected to be on. When the wide detection switch 23 is turned on, the motor 22 is stopped in step S21.

That is, according to such a processing procedure, the light emitting unit operates as follows during the storage operation.

(b) When the light emitting unit is in the retracted position as shown by the solid line in Fig. 6: As is clear from the figure, the up switch 25 is off and the process proceeds from step S2 to 83, and in the retracted position the light emitting unit is wide. Since the detection switch 23 is on, the motor 22 is not driven.

(b) When rotating the light emitting unit to the storage position when the light emitting unit is in the up position and wide zoom state as shown in Fig. 2: Before the storage operation, the up switch 25 is on, but as the operation starts, the up switch 25 is turned on. Since the switch 25 is turned off, the process advances from step S2 to step s3.

Since the light emitting unit is already in the wide zoom state, the wide detection switch 23 is on, and the motor is not driven in this case as well.

(c) When rotating the light emitting unit to the storage position when the light emitting unit is in the up position and in the telezoom state as shown in FIG. As the up switch 25 is turned off, the process advances from step s2 to step S3. At this time, the light emitting unit is in the telezoom state, so the wide detection switch 23 is off. For this reason, step S4
, reverse the motor 22, and turn the wide detection switch 23
The motor 22 continues to be driven until it is turned on, and when the wide detection switch 23 is turned on, the motor 22 is stopped in step S6. According to this processing procedure, as shown by the two-dot chain line in FIG. 6, when the light emitting unit that is up in the telezoom state is retracted, the protector 17 immediately retreats. Therefore, the storage space within the camera body can be reduced. In addition,
In FIG. 6, 71 indicates a camera body, and 72 indicates a pentaprism.

Next, a motor control processing procedure during photographing and a photographing sequence will be explained.

(b) If the sensitivity of the film being used is less than the maximum sensitivity determined by the exposure error in the telezoom state, and the light emitting unit is in the up position and a telephoto lens is attached: Since the sensitivity is less than the maximum sensitivity (indicated by Sv in FIG. 5) determined by the exposure amount error of the film in the telezoom state and the light emitting unit is in the up position, the process proceeds from step S2 to step s8 via 87.

Since a telephoto lens is attached here, when the half-press switch 52 is turned on, information on the attachment of the telephoto lens is sent from the focal length signal output circuit 56 to the microcomputer 50, so steps S8 to S9 Proceed to. If the light emitting unit is already in the telezoom state, the telephoto detection switch 24 is on, so the motor 22 is not driven. On the other hand, when the light emitting unit is in the wide zoom state, steps S2 to 88 are the same as described above, but since the telephoto detection switch 24 is turned off in step S9, the process proceeds to step SIO, where the motor 22 is rotated in the forward direction. Continue driving until the telephoto detection switch 24 is turned on.
When the telephoto detection switch 24 is turned on, the motor 22 is stopped in step S12. This causes the light emitting unit to enter the telezoom state.

(b) If the film sensitivity used is less than the maximum sensitivity determined by the exposure error of the film in telezoom mode, and the light emitting unit is in the up position and a wide-angle lens is attached: If the film is currently loaded in the camera. Since the sensitivity of the film is less than the maximum sensitivity (indicated by Sv in FIG. 5) determined by the exposure amount error of the film in the telezoom state; and the light emitting unit is in the up position, step S
The process proceeds from 2 to 87 to S8.

Here, since the wide-angle lens is attached, information about the attachment of the wide-angle lens is sent from the focal length signal output circuit 56 to the microcomputer 5o, so step S8
→S17→S18.

If the light emitting unit is already in the wide zoom state, the wide detection switch 23 is on, so step S18 is affirmed and the motor 22 is not driven. - On the other hand, if the light emitting unit is in the telezoom state, steps 88 to S1
The steps up to step S7 are the same, but since the wide detection switch 23 is turned off in step S818, the process advances to step S19. Here, the motor 22 is reversed and the wide detection switch 2
3 is turned on, and when the wide detection switch 23 is turned on, the motor 22 is stopped in step S21. As a result, the light emitting unit enters a wide zoom state.

(c) If the film sensitivity used exceeds the maximum sensitivity determined by the exposure amount error in the telezoom state, and the light emitting unit is in the up position, the flash dimming characteristics when using film exceeding the second reference value Sv, for example, 1
As shown in Figure 0.

In the figure, an exposure amount error of about 1.5 steps occurs on the short distance side of bar line f2(T) (tele zoom state with aperture 2). However, at f2(W) (wide zoom state with aperture 2), the exposure amount error is less than one step even on the short distance side. Therefore, in the wide zoom state, the exposure error is within the allowable exposure error of the flash device, so that it is possible to use a film with a film sensitivity exceeding the reference value Sv.

Under the current condition (c), the sensitivity of the film loaded in the camera exceeds the maximum sensitivity (indicated by Sv in Figure 5) determined by the film exposure error in the telezoom state, and the light emitting unit is in the up position. Therefore, step S2
The process then proceeds to step S13 via step S7. At this time, if the first light emitting unit is in the wide zoom state, the wide detection switch 23 is on, so step S1
3, the process returns to step S2 again, and the motor is not driven.

Next, if the light emitting unit is in telezoom mode,
Since the wide detection switch 23 is off, step S
Proceed to step 14. In step S14, the motor 22 is reversed and continues to be driven until the wide detection switch 23 is turned on, and when the wide detection switch 23 is turned on, step S16
The motor 22 is stopped at . According to this processing procedure, when a film exceeding the maximum sensitivity determined by the film exposure amount error in the telezoom state is used, the light emitting unit always enters the wide zoom state.

Next, the photographing sequence will be explained.

When the release button (not shown) is further pressed, the release switch 51 is turned on and the shutter (not shown) starts running.

When the shutter front curtain completes travel, the IS switch 61 is set to f.
Move away from the terminal. Due to this switching, the dimming control circuit 58 starts an integral operation. In addition, the IS switch 61
When the g terminal contacts the g terminal, the g terminal of the light emitting circuit 60 falls to the ground, the light emitting circuit 60 gives a well-known trigger signal to the light emitting section 16, and the light emitting section 16 starts emitting light. TTL dimming 5
The PD 59 receives the light reflected from the film and outputs a photocurrent to the dimming control circuit 58. The dimming control circuit 58, which has already started an integral operation by switching the IS switch 61, integrates the output of the photocurrent, and when the integrated value reaches a certain level, sends a signal to the light emitting circuit 60 to stop emitting light. . Thereafter, a shutter trailing curtain (not shown) runs, and from then on, well-known camera operations such as film winding and shutter charging are performed.

In the first modified example and above, during flash photography where the sensitivity of the film used exceeds the reference value Sv, the light emitting unit is set to the wide zoom state regardless of the focal length of the attached lens. Thus, even if the film sensitivity exceeds the reference value Sv, for example, if the distance of the aperture f2(T) is 6 m or more, the exposure error is one step or less, and there is no need to switch to the wide zoom state. In particular, when switching to the wide zoom state, there is a risk that the exposure amount will be insufficient at f2 (W) when photographing at a distance of about 10 m or more. For this reason, it is desirable to read the film sensitivity, aperture value, and photographing distance, and to enter the wide zoom state only under conditions where the exposure amount error is one step or more. This is due to the above-mentioned 3 cases which result in an exposure amount error of one step or more.
This can be easily achieved by determining and storing a combination of two conditions, and setting the wide zoom state only when that combination is detected during shooting.

In addition to the configuration of the above embodiment, if a film with a sensitivity such that the exposure error in the wide zoom state at the maximum aperture is one stop or more on the short distance side is used, the release may be disabled or the flash may be disabled. Functions may be added.

Furthermore, although the zoom flash device has been described above as a built-in camera type, the present invention can also be applied to an external zoom flash device. In this case, in a system in which the external zoom flash device has a built-in circuit for controlling wide zoom switching, information on the film sensitivity used may be transmitted from the camera to the flash device.

In this embodiment, the zoom flash device with variable illumination angle is described in detail, but not only this but also other guide number variable methods 1, such as a method of inserting and removing a dimming plate in front of the arc tube, and The present invention can also be applied to a flash device in which a liquid crystal is provided in the flash device and its transmittance is variable.

Next, another example will be described.

In Figure 4, wide and tele detection switches 23 and 24
Information on the wide zoom state and telezoom state detected by the microcomputer 50 is input to the microcomputer 50. The microcomputer 50 receives an information signal indicating the telezoom state from the detection switch 24, and activates a warning display circuit 71 when it is determined that the film sensitivity read from the film sensitivity reading circuit 55 is higher than the film sensitivity reference value Sv. When the information signal indicating the wide zoom state is inputted from the detection switch 23 after the warning is displayed, the warning display circuit 71 is made inactive.

This warning display circuit 71 may be provided, for example, in an electronic flash device or in a camera body. As the warning display method, there are a method of visually warning the user and a method of warning the user audibly.

In the embodiment, the irradiation intensity of the light emitting section was changed by changing from the tele zoom state to the wide zoom state, but it can also be easily implemented by the method described below. For example, the amount of light irradiated by the cannon tube 16a itself may be changed, or the dimming level of the dimming control circuit 58 may be changed.

First, changing the amount of irradiation light will be explained. If the light emitting circuit 60 of the embodiment is provided with one, for example, a plurality of main capacitors, and the main capacitor used for light emission is appropriately selected according to the amount of irradiated light, the amount of irradiated light to be controlled can be easily obtained. As a result, even when a high-sensitivity film is loaded as in the example, the amount of irradiation light can be easily controlled.
It is possible to prevent exposure errors of one or more stages of film.

Next, changing the dimming level will be explained. The dimming control circuit 58 normally sets a dimming level based on exposure information such as film sensitivity information sent from the CPU 50 and controls the light emission of the light emitting section to obtain an appropriate amount of exposure. By correcting, the amount of irradiation light can be changed in the same way as in the example, so when a high-sensitivity film is loaded as in the example, the light adjustment level can be corrected to prevent an exposure amount error of one step or more from occurring on the film. You can do it like this.

Effect of the G0 Invention According to the invention of claim 1, it is possible to use a film that exceeds the maximum film sensitivity determined by the exposure amount error when the light emission intensity is high, so the film sensitivity that can be used during flash photography is high sensitivity. The sides are wider, making it easier to use. Furthermore, according to the second aspect of the invention, a warning is issued when film sensitivity equal to or higher than a predetermined value is read in the telezoom state, thereby preventing photographing with an inappropriate exposure amount.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are complaint correspondence diagrams. FIGS. 2 to 6 illustrate an embodiment of the flash photography device according to the present invention, and FIGS. 2 and 3 are perspective views of the light emitting unit, and FIG. 2 shows the wide zoom state, FIG. 3 shows the telezoom state. FIG. 4 is an electric circuit block diagram, FIG. 5 is a flowchart showing a zooming motor drive control processing procedure, and FIG. 6 is a sectional view showing a state in which the light emitting unit is housed. Figure 7 is a light emission time characteristic diagram of the auto flash device, Figure 8
10 to 10 are diagrams showing three examples of flash dimming characteristics with different film sensitivities, and FIG. 8 shows the case where the film sensitivity is the lowest. 16: Light emitting part 17: Protector 17a: Diffusion plate 17b Neck 18: Gear 20
: Motor 50: Microcomputer 55: Film sensitivity reading circuit 56: Focal length signal output circuit 58: Light control circuit 59: Light receiving element 101: Light emitting section 102: Changing means 103: Automatic light control means 1o
4: Control means 105: Display control means 106: Detection means Patent applicant Nippon Kogaku Kogyo Co., Ltd. Representative patent attorney Fuyu Nagai 17') Mipu

Claims (1)

[Scope of Claims] 1) a light emitting unit that illuminates a subject; a changing unit capable of changing the illumination angle of the light emitting unit between a wide zoom state where the illumination angle is wide and a telezoom state where the illumination angle is narrow; In a flash photography device having automatic light control means that monitors the amount of light reflected from the subject by light emission from the light emitting unit and stops the light emission when a predetermined light level is reached, when the light emitting unit is in a telezoom state, 1. A flash photographing device comprising a control means for controlling said changing means to forcibly bring said light emitting section into a wide zoom state when film sensitivity is greater than or equal to a predetermined value. 2) a light emitting unit for illuminating a subject; a changing means capable of changing the illumination angle between a wide zoom state in which the illumination angle of the light emitting unit is wide and a tele zoom state in which the illumination angle is narrow; In a flash photography device having automatic light control means that monitors the amount of light reflected from a subject and stops emitting light when a predetermined light amount level is reached, the changing means detects whether it is in a wide zoom state or a telezoom state. a detecting means; when the detecting means detects that the changing means is in the telezoom state and the read film sensitivity is a sensitivity higher than a predetermined value, a warning is displayed; 1. A flash photography device comprising: display control means for detecting a change from a tele zoom state to a wide zoom state and canceling the warning display. 3) In the flash photography device according to claim 1, sensitivity detection means detects the film sensitivity, distance detection means detects distance information corresponding to the distance to the subject, and detects an aperture value of the photographic lens. aperture detection means, and the control means controls the changing means to a wide zoom state only when an exposure amount error determined by the film sensitivity, the distance information, and the aperture value is equal to or greater than a predetermined value. Features a flash photography device. 4) In the flash photography device according to claim 2, sensitivity detection means detects the film sensitivity, distance detection means detects distance information corresponding to the distance to the subject, and detects an aperture value of the photographic lens. and an aperture detection means, wherein the display control means detects that the change means is in the telezoom state by the detection means, and
A flash photography device characterized in that the display warning is controlled only when an exposure amount error determined by the film sensitivity, the distance information, and the aperture value is equal to or greater than a predetermined value.