JP3218701B2 - Electronic flash device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic flash device used in combination with a camera and capable of automatically setting a light distribution angle.

[0002]

2. Description of the Related Art Conventionally, it is used in combination with a camera,
As an electronic flash device capable of automatically setting a light distribution angle, for example, a device disclosed in Japanese Patent Application Laid-Open No. 62-196635 is known. In this electronic flash device, focal length information of a photographing lens is detected. Then, the light distribution angle of the electronic flash device is automatically adjusted to a value corresponding to the focal length information by using the motor driving force.

A similar electronic flash device disclosed in Japanese Patent Application Laid-Open No. 1-259336 is known. In this electronic flash device, focal length information of a photographing lens can be transmitted to the electronic flash device. Only when the camera is a camera, the light distribution angle of the electronic flash device is automatically set.

In the electronic flash devices disclosed in these publications, since the light distribution angle of the electronic flash device is automatically set in conjunction with the angle of view of the photographing lens, the light emission energy of the electronic flash device is effectively used. can do.

[0005]

However, in the above-described electronic flash device disclosed in Japanese Patent Application Laid-Open No. 1-259336, when focal length information is newly transmitted, for example, when a photographing lens is exchanged, it is unconditionally required. Since the camera returns to the auto zoom, there is a problem that it is very difficult for a photographer who wants to perform a manual zoom operation.

That is, in general, the light distribution of an electronic flash device tends to decrease as it approaches the angle of view, and the photographic lens itself also has a decrease in the peripheral light amount such as the cosine fourth power law. When shooting with the device, the amount of peripheral light may become a problem.The photographer who is familiar with this problem should manually set the light distribution on the wide-angle side from the light distribution corresponding to the focal length information, and obtain a relatively uniform light distribution. Although the central part of light is used for photographing, in this case, if the automatic zooming is unconditionally returned, the electronic flash becomes very difficult to use.

In general, in an electronic flash device, the light distribution angle is adjusted using the driving force of a motor. Therefore, the light distribution angle is controlled with a certain time delay after the focal length of the photographing lens changes. Therefore, for example, when the zoom lens is quickly moved from telephoto to wide-angle, the light distribution control of the auto zoom may not be in time, and vignetting of the light distribution may occur in the release immediately after that, in such a case, The photographer previously sets the light distribution angle on the wide-angle side manually before taking a picture. In this case, if the camera returns to the auto-zoom unconditionally, it becomes very difficult to use the electronic flash device.

Further, in photographing on the premise of trimming, it is sufficient that the light distribution angle can cover the screen remaining after trimming, so that the light distribution on the telephoto side is manually set in order to increase the guide number, or a spotlight is used. In order to achieve the desired effect, the photographing is performed with the light distribution on the telephoto side set manually. In this case, if the automatic flash is returned unconditionally, the electronic flash device becomes very difficult to use.

The present invention has been made in order to solve such a conventional problem, and an electronic flash device capable of forcibly prohibiting a light distribution control by an automatic zoom and a light distribution control by a manual zoom are almost used. An object of the present invention is to provide an electronic flash device that can be made unnecessary.

[0010]

[0011]

According to a first aspect of the present invention, there is provided an electronic flash device comprising: a communication unit for exchanging information with a camera; a light distribution angle changing unit for changing a light distribution angle of a light emitting unit; Control means for setting the light distribution angle based on the focal length information of the photographing lens from the camera received from the camera, and controlling the light distribution angle changing means so as to have the set light distribution angle. In the above, the control means sets the light distribution angle to be wider by a predetermined angle when the aperture value of the taking lens is more open than a predetermined value (for example, steps S124 and 125 in FIG. 5). , 126).

[0012]

According to a second aspect of the present invention, there is provided an electronic flash device, comprising: a communication unit for exchanging information with the camera; a light distribution angle changing unit for changing a light distribution angle of the light emitting unit; An electronic flash device comprising: a light distribution angle set based on focal length information of a photographing lens; and control means for controlling the light distribution angle changing means so as to have the set light distribution angle.
The control means calculates the maximum shooting distance from the film sensitivity received from the communication means, the aperture value of the taking lens, and the guide number stored in the control means, and receives the calculated value from the communication means. 6 (for example, steps S128 and S132 in FIG. 6), and when the farthest shooting distance is longer than a predetermined number of steps, the light distribution angle is set wider by a predetermined angle (for example, FIG. Step S133).

According to a third aspect of the present invention, there is provided an electronic flash device according to the first or second aspect.
3. The electronic flash device according to claim 2 , wherein the control means sets the light distribution angle to be wide only when a signal for setting a wide light distribution angle is input from the external input means (for example, step S123 in FIG. 6). )

[0015]

[0016]

According to the electronic flash device of the first aspect , when the aperture value of the photographing lens is more open than a predetermined value,
The light distribution angle is set wider by a predetermined angle.

[0017] In the electronic flash device according to claim 2, calculated by the actual photographing distance and the farthest object distance obtained is compared, farther than a predetermined number or more actual shooting distance farthest object distance is predetermined Sometimes, the light distribution angle is set wider by a predetermined angle.

[0018] In the electronic flash device according to claim 3, claim 1 or
Alternatively, the light distribution angle is set wider only when a signal for setting a wider light distribution angle is input from the external input means in step (2 ).

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a first embodiment of an electronic flash device according to the present invention, wherein 1 is an electronic flash device, 2 is a camera,
Reference numeral 3 denotes a photographing lens.

The electronic flash device 1, the camera 2 and the photographing lens 3 include a flash device control circuit 11, a camera control circuit 21
And a photographing lens control circuit 31. These control circuits 11, 21 and 31 are each constituted by a CPU.

Flash device control circuit 11 and camera control circuit 2
1 is connected via a data interface 12, and the camera control circuit 21 and the lens control circuit 31 are connected via a data interface 32.

The electronic flash device 1 is provided with a well-known light distribution angle changing mechanism 8 including a convex lens 4, a reflecting mirror 5, an arc tube 6, and a motor 7. The reflecting mirror 5 and the arc tube 6 are integrated, and the light distribution angle is changed by changing the distance between the convex lens 4 and the arc tube 6 by driving the motor 7.

Reference numeral 12 denotes a light distribution angle detection circuit for detecting a light distribution angle from the distance between the convex lens 4 and the arc tube 6, and 13 denotes a motor drive circuit for driving the motor 7. Reference numeral 14 denotes an external input circuit for inputting information intended by the photographer from outside. The external input circuit 14 includes a manual button 15 and a zoom button 16.

The camera control circuit 21 of the camera 2 is connected to a film sensitivity detection circuit 22 for detecting film sensitivity and an exposure control circuit 23 for controlling exposure. The photographing lens control circuit 31 of the photographing lens 3 includes a focal length data detecting circuit 33 for detecting focal length data of the photographing lens,
An imaging distance detection circuit 34 for detecting an imaging distance (subject distance) from the lens position and an aperture value detection circuit 35 for detecting an aperture value are connected.

FIG. 2 shows the appearance of the electronic flash device 1, in which a light emitting section 9 is formed at the top. Reference numeral 10 denotes a display unit composed of an LCD for displaying various information. Below the display unit 10, a manual button 15, a zoom button 16,
And a power switch 17.

At the lower end, a leg electrical contact 18 connected to the camera 2 is arranged. Hereinafter, the operation of the first embodiment of the present invention will be described in detail with reference to the flowcharts shown in FIGS.

In the first embodiment, in the electronic flash device 1 capable of auto-zoom, an auto-zoom cancel mode in which only manual zoom is forcibly selected by a photographer's intention is realized.

FIG. 3 shows a process relating to the setting of the auto zoom cancel mode. The execution of the auto zoom cancel mode is performed according to a cancel flag in the CPU constituting the flash device control circuit 11, and the cancel flag is set to 1 Will force only manual zoom to be selected.

Hereinafter, the operation will be described in the form of a subroutine repeatedly executed from the main routine of the flash device control circuit 11. First, it is determined whether both the zoom button 16 and the manual button 15 of the external input circuit 14 are pressed (ON) (S101, S102). If both are ON, the process proceeds to step S103. Is reset (step S105).

If the timer has exceeded the predetermined time, for example, 2 seconds in S103, it is determined that an operation relating to the setting of the auto zoom cancel mode has been performed, and the cancel flag is inverted (step S104).

On the other hand, if the timer has not exceeded at step S103, the process returns (step S106). That is, the zoom button 1 of the external input circuit 14
Only when both the button 6 and the manual button 15 are continuously pressed for two seconds, the setting and cancellation of the auto zoom cancel mode are performed.

If the cancel flag is set to 0 in the initial setting of the flash device control circuit 11, the automatic zoom cancel mode is entered by the first operation. FIG. 4 is a flowchart of a light distribution control process that enables execution of the auto zoom cancel mode. The light distribution control process is described in the form of a subroutine repeatedly executed from the main routine.

This light distribution control subroutine is performed by first determining whether the cancel flag is 0 or 1 (step S111). If the cancel flag is 0, the auto zoom cancel mode is not set,
Control by auto zoom is performed as in the conventional case.

That is, first, it is checked whether or not the focal length data (f data) of the photographing lens 3 has been transmitted from the camera 2 (step S112). In this embodiment, the focal length data is detected by the focal length data detecting circuit 33 of the photographing lens 3, and the detected focal length data is transmitted to the flash device via the photographing lens control circuit 31 and the camera control circuit 21. It is input to the control circuit 11.

The above-mentioned check is performed by first checking whether the focal length data transmitted by the camera 2 is valid. For example, when the photographing lens 3 is not mounted on the camera 2 or when the photographing lens 3 is mounted but does not have the electrical focal length information, the focal length information of the camera 2 is unknown. As there is, specific data from the camera control circuit 21, for example,
8-bit serial data $ 00 is flash device control circuit 1
1 is input.

In this case, the flash control circuit 11 determines in advance that there is no focal length data according to the rule that the focal length data $ 00 means that the focal length data is unknown. Also, when the focal length data is not transmitted from the camera 2 for a predetermined time or longer, such as when the electronic flash device 1 is detached from the camera 2, the flash device control circuit 11 clears the focal length data to $ 00 and sets the focal length data to $ 00. Judge as no.

When the flash device control circuit 11 determines that there is focal length data, it is determined whether the manual flag is 0 or 1 (step S113). When the flag is 0, the automatic zoom is selected. Then, it is determined whether the zoom button 16 has been newly pressed (step S115).

When the zoom button 16 is not pressed, the light distribution is controlled by the automatic zoom (step S121). On the other hand, when the cancel flag is 1 in step S111, since the automatic zoom cancel mode is set, the light distribution control is performed manually.

That is, first, it is determined whether or not the zoom button 16 has been newly pressed (step S117). When the zoom button 16 has not been pressed, the light distribution control is manually performed (step S119).

On the other hand, when the zoom button 16 is pressed in step S117, the light distribution angle is changed in a predetermined order (step S118). This light distribution angle is changed, for example, every time the zoom button 16 is pressed once, from 24 mm to 35 m.
The light distribution is changed to cover the photographing lens of m → 50 mm → 75 mm, and when the zoom button 16 is pressed, the light distribution becomes 24 m.
m, and the above procedure is repeated in the same order.

The changed light distribution angle is stored in a storage circuit (not shown) of the flash device control circuit 11, and when the zoom button 16 is pressed next time, the light distribution angle is set to a value next to the stored value. You.

When the flash device control circuit 11 determines in step S112 that there is no focal length data, the automatic zoom cannot be performed.
Light distribution control is performed manually.

At this time, first, the manual flag in which the execution of the automatic zoom is set is set to 0, and the automatic zoom is permitted (step S11).
4). Accordingly, when it is determined that there is data next time in step S112, it is possible to start the processing of the auto zoom after step S113.

More specifically, when a photographing lens 3 having focal length data is newly attached to the camera 2, automatic zooming is automatically performed. In a conventional electronic flash device, this processing is always performed. Is being done.

Further, even when the zoom button 16 is pressed in step S115, manual light distribution control is performed. At this time, the manual flag is set to 1 (step S116), the manual zoom is set,
Thereafter, even if there is focal length data, light distribution control by manual zoom is performed.

In the above-described electronic flash device, when the manual button 15 and the zoom button 16 are simultaneously pressed, when the cancel flag is set to 1,
Since the light distribution control by the manual zoom is performed, the light distribution control by the automatic zoom can be forcibly prohibited, and therefore, it is possible to reliably prevent the automatic switching to the automatic zoom against the photographer's intention.

In this embodiment, when the auto-zoom cancel mode is set, the light distribution display on the display unit 10 of the electronic flash device 1 blinks, or
By turning on the dedicated display unit, the photographer can easily recognize that the auto zoom cancel mode is set.

FIG. 5 is a flowchart of a second embodiment of the electronic flash device according to the present invention. In the second embodiment, the light distribution is broadened based on the focal length of the photographing lens 3 and the aperture value. Control (hereinafter referred to as broad light distribution control) is performed.

In this flowchart, FIG.
Steps that perform the same operations as the steps shown in (1) are given the same numbers, and in this embodiment, step S
123 and later are added.

The cancel flag in S111 is not set, but a broad flag is set instead. The setting of the broad flag is performed in the same manner as the setting of the cancel flag shown in FIG. 2, or by a dedicated setting switch. For example, when the broad flag is 1, the broad mode is set.

In this embodiment, when the zoom button 16 is not newly pressed in step S115, it is determined whether or not the broad flag is 1, that is, whether or not the broad mode is set (step S12).
3).

When the broad mode is set, the focal length of the taking lens is, for example, f = 50 m
m and the aperture value is F4 or less (small aperture), the broad light distribution control is performed (steps S124, 125,
126).

In this embodiment, the focal length is detected by the focal length data detection circuit 33, and the aperture value is detected by the aperture value detection circuit 35. This broad light distribution control is performed, for example, by shifting the light distribution angle as shown in the following table. That is, when the conventional light distribution control by the auto zoom is, for example, 50 mm, 35 mm on the one-position wide angle side is used.
The control for setting the light distribution angle is performed.

In the following, it is also assumed that the position is shifted by one position at each light distribution angle position, and only the light distribution angle of 24 mm at the wide-angle end is left as it is because the light distribution angle cannot be further widened. On the other hand, when f> 50 mm in step S124,
The light distribution control by the automatic zoom is performed without performing the broad light distribution control (step S121).

This is because the light distribution angle is relatively flat on the telephoto side, and since the photographing is mainly performed at a distant place, the guide number is reduced. Therefore, it is not necessary to perform the broad light distribution control. .

Also, when F> 4 in step S125, the light distribution control by the automatic zoom is performed without performing the broad light distribution control (step S121). this is,
This is because it is not necessary to perform the broad light distribution control because the peripheral lens light amount decrease due to vignetting is small because the photographing lens is narrowed.

However, in the above-described electronic flash device, the light distribution angle is set to be wider by a predetermined angle when the aperture value of the photographing lens is on the open side than a predetermined value. Even with zooming, a uniform light distribution intended by the photographer can be reliably obtained, and light distribution control by manual zoom can be almost eliminated.

Also, in this embodiment, the light distribution angle is set wider only when the broad mode is set.
The degree of freedom of the photographer's selection is increased. FIG. 6 shows a flowchart of a third embodiment of the electronic flash device according to the present invention. In the third embodiment, in addition to the focal length and the aperture value of the taking lens, the taking distance is taken into consideration. Broad light distribution control is performed.

In this flowchart, FIG.
Steps that perform the same operations as the steps shown in (1) are given the same numbers, and in this embodiment, steps S1
28 and after are added.

In this embodiment, the focal length of the photographic lens is determined by the focal length data detection circuit 33, the actual photographic distance is determined by the photographic distance detection circuit 34, the aperture value is determined by the aperture value detection circuit 35, and the film sensitivity is determined by film. The exposure value is detected by the exposure control circuit 23 by the sensitivity detection circuit 22.

In this embodiment, when the focal length of the photographing lens is, for example, f = 50 mm or less in step S124, it is checked whether or not there is a guide number for the photographing to be performed (step S128).

The determination of the margin is based on the maximum photographing distance (Gv +
Sv−Av) and the actual shooting distance Dv transmitted from the camera 2 is calculated by calculating how many steps there is a margin.

That is, Gv is a guide number when the film sensitivity Sv = 0, and has a value for each light distribution angle. Gv + Sv represents an actual guide number by apex calculation, and the farthest shooting distance can be obtained by subtracting the aperture value Av from Gv + Sv.

If the farthest photographing distance has, for example, two or more steps with respect to the actual photographing distance Dv transmitted from the camera 2, even if the light distribution angle is wider, the guide number does not decrease.

In step S128, when there is no more than two steps, light distribution control by ordinary automatic zoom is performed (step S121). On the other hand, if there is room for two or more stages in step S128, broad light distribution control is performed.

First, the zoom position of the electronic flash device 1 is provisionally set to the position of the automatic zoom (step S129).
At this stage, the motor 7 is not driven by the motor drive circuit 13 and only the control value is set.

Thereafter, it is checked whether or not the current set value is already at the wide-angle end (step S130). If it is at the wide-angle end, no more broad light distribution control is possible, so the broad light distribution control is performed. (Step S133).

On the other hand, if it is not the wide-angle end, the zoom control value is moved to the one-position wide-angle side (step S13).
1) Then, the same operation as in step S128 is performed (step S132).

By moving to the wide angle side by one position, G
Although the v value is small, if there is still room for two or more steps, the process returns to step S130, and when there is no room for two or more steps, the motor 7 is driven by the motor drive circuit 13 to perform broad light distribution control. (Step S13)
3).

In the electronic flash device described above, the longest shooting distance obtained by calculation is compared with the actual shooting distance, and the longest shooting distance is equal to or more than a predetermined number of steps. When far away, the light distribution angle is set wider by a predetermined angle, so that even with auto zoom, a uniform light distribution intended by the photographer can be reliably obtained, and light distribution control by manual zoom is almost unnecessary. can do.

In this embodiment, the light distribution angle is set wider only when the broad mode is set.
The degree of freedom of the photographer's selection is increased. In the third embodiment, since the margin of the guide number is taken into consideration, it is not always necessary to divide the case according to the focal length in step S124.

Further, in the third embodiment, the setting of the broad mode may be omitted, and the broad mode may always be set in step S123.

[0073]

[0074]

As described above, in the electronic flash device according to the first aspect , when the aperture value of the photographing lens is more open than the predetermined value, the light distribution angle is increased by a predetermined angle. Therefore, even with the automatic zoom, a uniform light distribution intended by the photographer can be reliably obtained, and the light distribution control by the manual zoom can be almost eliminated.

[0075] Further, in an electronic flash device according to claim 2 and 3, calculated at the actual photographing distance and the farthest object distance obtained is compared with a predetermined the farthest object distance is predetermined number or more actual when far from the shooting distance, since the light distribution angle by a predetermined angle is set to spread, by auto zoom,
It is possible to reliably obtain a uniform light distribution intended by the photographer,
Light distribution control by manual zoom can be almost eliminated.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a circuit configuration of an electronic flash device according to a first embodiment of the present invention.

FIG. 2 is a front view showing the appearance of the electronic flash device of FIG.

FIG. 3 is a flowchart illustrating an operation of setting an auto zoom cancel mode according to the first embodiment.

FIG. 4 is a flowchart illustrating light distribution control according to the first embodiment.

FIG. 5 is a flowchart illustrating light distribution control according to a second embodiment.

FIG. 6 is a flowchart illustrating light distribution control according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electronic flash device 2 Camera 3 Shooting lens 11 Flash device control circuit 12 Data interface 13 Motor drive circuit 14 External input circuit 15 Manual button 16 Zoom button

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ryotaro Takayanagi 1-6-3 Nishioi, Shinagawa-ku, Tokyo Nikon Oi Works Co., Ltd. (56) References JP-A-5-11315 (JP, A) Kaihei 3-85536 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03B 15/05

Claims (3)

(57) [Claims] Communication means for exchanging information with a camera; light distribution angle changing means for changing a light distribution angle of a light emitting unit; and focal length information of a photographing lens from the camera received from the camera via the communication means. Control means for setting a light distribution angle based on the light distribution angle, and controlling the light distribution angle changing means so as to achieve the set light distribution angle.An electronic flash device comprising: An electronic flash device wherein the light distribution angle is set to be wider by a predetermined angle when it is on the open side than a predetermined value. 2. Communication means for exchanging information with a camera, light distribution angle changing means for changing a light distribution angle of a light emitting unit, and focal length information of a photographing lens from the camera received from the camera via the communication means. Control means for setting the light distribution angle based on the light distribution angle and controlling the light distribution angle changing means so that the light distribution angle becomes the set light distribution angle, wherein the control means receives the light from the communication means. The maximum shooting distance is calculated from the calculated film sensitivity, the aperture value of the shooting lens, and the guide number stored in the control unit, and the calculated value is compared with the shooting distance received from the communication unit. When the distance is more than a predetermined number of steps,
An electronic flash device characterized in that the light distribution angle is set wider by a predetermined angle. 3. The electronic flash device according to claim 1, wherein the control unit sets the light distribution angle to be wide only when a signal for setting a wide light distribution angle is input from an external input unit. An electronic flash device characterized by the above-mentioned.