JP2794109B2 - 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 having light distribution control means.

[0002]

2. Description of the Related Art As shown in FIG. 5, there has been an electronic flash device S in which a posture between horizontal positions a and c and a vertical position b can be selected by a rotating mechanism of a leg SL when a camera C is mounted. The reason for adopting such a mechanism is that the position of the light emitting portion SF of the electronic flash device S is to be moved with respect to the optical axis of the photographing lens CL for the purpose of controlling the shadow of the subject background in imaging using the electronic flash device. Because. The method in which the leg SL is provided with a rotation mechanism to rotate the entire electronic flash device S has many advantages such as small size and durability since the structure is simple.

By the way, the light distribution of the electronic flash device is wide in the horizontal direction in a 35 mm single-lens reflex camera as shown in FIG. 5 according to the angle of view of the camera, and it is preferable to narrow down the light distribution in the vertical direction. . That is, the object field can be illuminated more efficiently than the light distribution called non-directional light distribution or circular light distribution, the guide number increases, and the photographable distance increases. FIG.
The electronic flash device S has a light distribution in which the light distribution is narrowed down in the horizontal direction at the horizontal position a.

[0004]

In actual use of such an electronic flash device S, when the electronic flash device S is in the vertical position b, the light distribution in the horizontal direction is narrow, so that the angle of view of the photographing lens CL is small. May not be covered. For example, it is assumed that an electronic flash device S has a light distribution covering the imaging lens having a focal length of 35 mm at the lateral positions a and c using a photography lens having a focal length of 35 mm for the camera C. At this time, specifically, the light distribution in the vertical direction is 45 ° and the light distribution in the horizontal direction is 60 °.
It is. If the electronic flash device S is in the vertical position b, the vertical direction and the horizontal direction are switched, so that even if the vertical angle of view can be covered, the horizontal direction cannot be covered. Therefore, in the related art, it is inconvenient that a wide panel is mounted on the electronic flash device S only when the electronic flash device is set in the vertical direction, or the wide panel is always mounted and used with a reduced guide number because it is troublesome.

[0005] This problem is caused by the rotation of the light emitting section SF about the rotation mechanism of the leg SL. However, the light emitting section SF is prevented from rotating with respect to the angle of view of the camera C. For this purpose, the size of the electronic flash device is prevented from being reduced only by the rotation mechanism. Further, if the light distribution characteristic is made non-directional, there is no effect due to the rotation, but there is a disadvantage in that the guide number is reduced as described above.

Accordingly, the present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to use a method in which a light-emitting unit rotates around a rotation mechanism of a leg.
An object is to provide an electronic flash device in which an appropriate light distribution is automatically selected when a posture is changed.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, the camera can be rotated about an axis parallel to the optical axis of the camera, and the image of the camera can be rotated. In an electronic flash device whose light distribution changes with respect to an angle, as shown in a block diagram of FIG.
Variable light distribution means 2, attitude detection means 3 of the electronic flash device,
A calculation means for processing the setting result of the light distribution setting means and a detection result of the attitude detection means by the calculation means, and controlling the light distribution by the light distribution variable means based on the calculation result. Thereby, the rotation movement of the electronic flash device is detected by the posture detecting means,
Vignetting of the light distribution is prevented by optimally setting the light distribution covering the angle of view of the camera according to the attitude of the electronic flash device.

The light distribution setting means 2 may make settings from a setting member provided in the electronic flash device or may make settings from a setting member provided in the camera and transmit the setting via the communication means 5. . The attitude detecting means detects whether the electronic flash device is at a standard position or at a position other than the standard position. Further, the attitude detecting means is provided with a display means for indicating a light distribution state, and this display means displays the light distribution state based on the calculation result of the calculation means.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. Embodiment 1 Embodiment 1 assumes an electronic flash device S having a rotation function having a click stop at horizontal positions a and c and a vertical position b as shown in FIG. Electronic flash device S, Figure 2 (a)
As seen from the back of the device,
The electronic flash device main body 11 is rotatable with respect to the leg 12 with a structure shown in a perspective view and a partial perspective view seen from the side as shown in FIG. The board 1 fixed inside the leg 12
6, an electrode pattern 13 is provided on the main body 11 of the electronic flash device.
A brush 14 fixed to a substrate 15 fixed inside the device can contact the electrode pattern 13. Electrode pattern 13
2A has an arc shape of less than 180 ° as shown in FIG. 2A, and does not contact the brush 14 at the lateral positions a and c. The electrode pattern 13 is electrically at the GND level, and the brush 14 is connected to an input terminal of a microcomputer (not shown) inside the electronic flash device main body 11. Therefore, in the state of FIG. 2, the brush 14 is electrically open, and when the signal “H” is input to the microcomputer, the microcomputer causes the electronic flash device S to move the electronic flash device S to the horizontal positions a and c with respect to the angle of view of the camera C. Can be detected. The above corresponds to the posture detecting means 3 in FIG.

Next, a procedure until the light distribution varying means 2 of FIG. 1 is operated by calculation based on the result of the attitude detecting means 3 will be described with reference to the flowchart of the microcomputer described above. FIG.
Is a subroutine of this calculation. In step 10 (hereinafter referred to as # 10), it is determined from the state of the terminal of the microcomputer connected to the brush 14 whether the electronic flash device S is at the horizontal position a, c or the vertical position b. Is done. Strictly, the posture described above is determined to be a vertical position if it deviates slightly from the horizontal positions a and c. However, a wide light distribution is required at positions other than the horizontal positions a and c. Alternatively, it is only necessary to be able to identify the other. If the positions are the horizontal positions a and c, the process proceeds to # 11, and the light distribution is selected according to the light distribution setting as shown in Table 1 below. That is, Table 1 shows the normal light distribution of the electronic flash device S when the horizontal position is considered as the standard. The rest is # 13
Drives the well-known light distribution varying means 2 to obtain a desired light distribution.

[0011]

[Table 1]

When the vertical position b is determined in # 10, the process proceeds to # 12, and the result according to Table 2 below is obtained. That is, when the light distribution setting value is selected from Table 2 in accordance with the light distribution setting, for example, when the light distribution setting is a 35 mm lens cover, the setting value of the 28 mm lens cover at the time of the horizontal position is selected. ° x 60 ° is obtained. This is 3
Although the light distribution is too wide in the vertical direction for a 5mm lens,
In the horizontal direction, the electronic flash device S is the same as in the horizontal position,
No vignetting occurs. This achieves the original purpose.

[0013]

[Table 2]

When the light distribution of the electronic flash device S is displayed by the focal length in conjunction therewith, the value of the light distribution setting is displayed. Therefore, in the above example, even if the set value of the 28 mm lens cover is selected in the vertical position, the display is 35 mm.

Further, as an example that cannot be dealt with in principle, when the widest light distribution at the horizontal position is selected, there is no light distribution covering it at the vertical position b. Display. Specifically, in Table 2, 24 mm
When the light distribution is set, the light distribution covering the vertical position b cannot be selected.
4 mm light distribution is selected, and the display is 28 mm light distribution. This display alerts the photographer.

The above-mentioned light distribution setting means 1 may be provided by providing a setting member to the camera C and set via the communication means 5, or by using the setting member of the electronic flash device S for photographing. The user may set a desired value. In particular, in the latter case, since it is necessary to relate to display, it is necessary to take measures such as not displaying an unexecutable position in the vertical position b as described above.

(Second Embodiment) In a second embodiment, a description will be given of the arithmetic means 4 for an electronic flash device whose rotational movement can be fixed at an arbitrary angle. First, it is assumed that the light distribution is variable by the light distribution variable means 2 in a manner similar to the angle of view of the camera C, and that the center of the light emitting portion SF of the electronic flash device S moves with respect to the optical axis of the camera by rotational movement. It is assumed that the amount to be performed is negligibly small with respect to the shooting distance. Therefore, on the subject surface, it can be considered that the light distribution rotates on the optical axis with the rotational movement of the electronic flash device S.

In FIG. 4, it is assumed that the hatched portions indicated by the short side A and the long side B are the light distribution patterns P at the horizontal positions a and c of the electronic flash device S. The required light distribution, which can be known by the encoder or the like of the attitude detecting means 3 that the electronic flash device S has rotated by the angle θ, has a short side A × Kv including a hatched portion and a long side B × Kh. It becomes a rectangle. This K
v and Kh are geometrically determined by Kv = (A × ABS (Cosθ) + B × ABS (Sinθ)) / A Kh = (A × ABS (Sinθ) + B × ABS (Cosθ)) / B Note that ABS is a function that gives an absolute value. Then, the larger one of Kv and Kh is determined as the magnification K.
And the light distribution is enlarged by a factor of K on the object plane, it is possible to cover the angle of view without vignetting. By the way, the light distribution is K
To double the magnification is equivalent to covering the angle of view of a lens having a focal length of 1 / K times assuming that the object plane is sufficiently distant. Therefore, based on the magnification K obtained as a result of the above-described calculation, it can be understood that the light distribution should be controlled so as to cover a lens having a focal length of 1 / K at the position (reference position) before the rotation.

[0019]

As described above, according to the present invention, a light distribution without vignetting is automatically selected in accordance with a change in the attitude of an electronic flash device, which has been conventionally performed, and failure in photographing can be prevented. An extremely excellent effect can be obtained. In addition, even with an electronic flash device that can fix the posture at any angle so as to control delicate shadows, it is possible to obtain an optimal light distribution that is not too wide and minimize problems such as a decrease in guide number. An extremely excellent effect such as the ability to obtain is obtained.

Further, if the attitude detecting means is detected separately from the standard position of the electronic flash device or other positions, it can be realized with a simple configuration. Also, by displaying the light distribution state on the display means based on the calculation result of the calculation means, it is possible to notify the light distribution angle at a position other than the standard position. Therefore, if a position other than the standard position is set when the light distribution state is the widest in the standard position, a narrow light distribution state is displayed, so that the photographer can be alerted.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of an electronic flash device according to the present invention.

FIG. 2 is a rear view showing the configuration of an electronic flash device according to the present invention.
It is the partial perspective view seen from the side and the partial perspective view seen from the side .

FIG. 3 is a flowchart illustrating an operation of the electronic flash device according to the present invention.

FIG. 4 is a view for explaining the operation principle of an electronic flash device according to a second embodiment of the present invention.

FIG. 5 illustrates an electronic flash device to which the present invention is applied.
It is a front view .

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light distribution setting means, 2 ... Light distribution variable means, 3 ... Attitude detection means, 4 ... Calculation means, 5 ... Communication means, 11 ... Electronic flash device main body, 12 ... Leg, 13 ... Electrode pattern, 14 ... Brush , 15 ... board, 16 ... board, C ... camera, S ... electronic flash device.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Nobuyoshi Hagiuda 1-6-3 Nishioi, Shinagawa-ku, Tokyo Nikon Oi Works Co., Ltd. (56) References JP-A-60-80429 (JP, A) JP-A-62-12140 (JP, A) JP-A-2-93437 (JP, A) JP-A-64-9435 (JP, A) JP-A-53-104633 (JP, U) Int.Cl. ⁶ , DB name) G03B 15/05

Claims (6)

(57) [Claims] 1. An electronic flash device which is rotatable about an axis parallel to an optical axis of a camera as a rotation axis, and changes light distribution with respect to an angle of view of the camera by the rotation. Means, light distribution variable means, attitude detection means of the electronic flash device, and arithmetic means, processing the setting result of the light distribution setting means and the detection result of the attitude detection means with the arithmetic means, An electronic flash device, wherein the light distribution varying means controls light distribution based on a result of the calculation. 2. The electronic flash device according to claim 1, wherein the light distribution setting means is a setting member provided in the electronic flash device. 3. An electronic flash device according to claim 1, wherein said light distribution setting means is a setting member provided in a camera. 4. The electronic flash device according to claim 1, wherein said attitude detecting means detects a rotation position with respect to a rotation axis. 5. The electronic flash device according to claim 1, wherein the attitude detecting means detects the electronic flash device at a standard position or a position other than the standard position. 6. The electronic flash device according to claim 1, further comprising display means for displaying a light distribution state, wherein said display means displays the light distribution state based on a calculation result of said calculation means.