JPH0314653Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention relates to a photometry device for a camera. The present invention relates to a photometric device.

[Prior art]

In an average metering type automatic exposure camera, when the luminance distribution within the photographic screen varies greatly, such as in a backlit situation, the main subject is likely to be exposed inappropriately. In particular, when shooting outdoors, there is a very high probability that the upper part of the shooting screen will be empty, and the main subject will often be underexposed. To deal with this, cameras are widely used that set the photometry range of the photodetector slightly below the center of the shooting screen and determine exposure using so-called downward-weighted metering, which partially measures the light. There is.

However, in the above-mentioned downward-weighted metering camera, it works well when the camera is held in the normal horizontal position, but when the camera is held in the vertical position and the photometry is taken, the photometry range of the light-receiving element is Since the image will be biased to the right or left of the photographic screen, the probability that the main subject will be improperly exposed becomes extremely high.

[Purpose of invention]

The present invention was made in view of the above-mentioned conventional technology, and is a camera that performs downward-weighted metering when held in the normal horizontal position, but automatically automatically when held in the vertical position. To prevent inappropriate exposure of a main subject by switching to center-weighted photometry, and to surely switch a photometry range according to the photographing attitude of a camera.

[Structure of the idea]

In order to achieve the above object, the present invention pivots an arm member above a fixed lens barrel incorporating a photographic lens, and by rotating this arm member by gravity, the aperture plate fixed to the other end is removed. The photometry range is switched by moving it in front of the light receiving element provided below the fixed lens barrel. The aperture plate has an aperture aperture for horizontal position for downward-weighted metering formed in the center, and a pair of aperture apertures for vertical position for center-weighted metering on both sides. In this case, one of the aperture apertures for vertical position is located in front of the light receiving element depending on the rotational direction of the camera. The rotation of the arm member is restrained by magnetic force. When the camera is rotated to the vertical position, the magnetic force is released and the arm member rotates to the position where it touches the stopper, causing one of the vertical aperture apertures to move in front of the light receiving element. It is configured to be positioned.

[Configuration of Example]

In FIG. 1 showing a camera to which the present invention is applied, a cylindrical decorative ring 2 is fixed to the front surface of the camera 1, and a fixed lens barrel 3 is provided inside the decorative ring 2. The fixed lens barrel 3 is fixed to the camera 1,
A photographing lens 4 is supported inside the lens so as to be movable in the direction of its optical axis. Furthermore, decorative ring 2
An arm 5 is swingably attached to the front surface of the camera 1 surrounded by a shaft 6. The position of the shaft 6, that is, the shaft attachment position of the arm 5 is set directly above the optical axis of the photographic lens 4. Further, a light receiving element 8 is provided directly below the optical axis of the photographic lens 4.

The free end of the arm 5 has through holes 7a, 7.
A diaphragm plate 7 on which holes b and 7c are formed is fixed, and as will be described later, one of these through holes 7a to 7c is selectively placed in front of the light receiving element 8. There is.

Protrusions 2a and 3a provided on the inner periphery of the decorative ring 2 and the outer periphery of the fixed lens barrel 3, respectively, are connected to the arm 5.
This is a stopper that restricts the swing position of the Further, an iron piece 9 is provided on the lower edge of the arm 5, and a magnet 10 is provided on the inner periphery of the lower part of the decorative ring 2. In the state shown in FIG. is giving. Note that after each of the above members is attached, the front surface of the decorative ring 2 is covered with a transparent protective cover (not shown).

[Effect of the embodiment]

When taking pictures with the camera 1 held in the normal horizontal position as shown in FIG. 1, the arm 5 is placed in the position shown in FIG.
a will be placed in front of the light receiving element 8.
The through hole 7a of the aperture plate 7 is connected to the light receiving element 8 as shown in the figure.
It is formed so that it is below the light-receiving surface. Therefore, as shown in FIG. 4, the photometric range of the light-receiving element 8 is set by the through hole 7a of the diaphragm plate 7 along the photometric optical axis 12 directed downward of the photographing screen.

When the camera 1 is held in the horizontal position in this way, as shown in FIG. 7, the photometry range 32 is slightly biased downward within the photographic screen 30, allowing photography to be performed under downward weighted metering. The exposure for the main subject 35 becomes appropriate. Note that the width of the photometric range 32 can be set depending on the size of the through hole 7a.

Furthermore, as mentioned above, when taking pictures with the camera 1 held in the horizontal position, since the magnet 10 attracts the iron piece 9, the swinging of the arm 5 is restricted, and the camera 1 is slightly tilted from the horizontal position. In addition, it is possible to ensure photographing using downward-focused metering, and also to prevent the arm 5 from swinging unnecessarily, eliminating the possibility of erroneous metering.

When the camera 1 is placed in a vertical position, that is, tilted 90 degrees clockwise from the horizontal position in Fig. 1, the arm 5 is released from its restraint by the magnet 10 due to its own weight during the tilting process. 5 swings around an axis 6. and,
After the side edge of the arm 5 comes into contact with the protrusion 2a of the decorative ring 2, it is rotated integrally with the camera 1 to be in the state shown in FIG. be located. As shown in the figure, the through hole 7b is formed at the center of the light receiving surface of the light receiving element 8.
Therefore, as shown in FIG. 6, the photometric range of the light receiving element 8 is set by the through hole 7b of the diaphragm plate 7 along the photometric optical axis 14 toward the center of the photographic field.

When the camera 1 is held in the vertical position in this manner, photography can be performed using center-weighted metering in which the metering range 33 is set at the center of the photographic screen 30, as shown in FIG. , the exposure for the main subject 35 becomes appropriate.

Generally, when photographing is performed in a vertical position, the probability that the main subject will be in the center of the photographic field is extremely high, so it is effective to use center-weighted metering as described above. Note that the width of the photometric range 33 can be set by the size of the through hole 7b, and by changing the sizes of the through holes 7a and 7b in advance, the width of the photometric range 32 in the horizontal position and the vertical position can be adjusted. The width of the photometry range 33 may be different from that of the photometry range 33.

When the camera 1 is rotated in the opposite direction to the vertical position, the arm 5 comes into contact with the protrusion 3a of the fixed lens barrel 3, and the aperture plate 7 is placed in front of the light receiving element 8. Although the through hole 7c is located, the light receiving element 8
The photometric range is the same as in FIG. 6 or 8.

[Effect of idea]

As described above, in this invention, exposure is determined by bottom-weighted metering when the camera is in the horizontal position, and center-weighted metering is used when the camera is in the vertical position. The main subject can be photographed with the appropriate exposure. Moreover, since the switch from bottom-weighted metering to center-weighted metering occurs when the camera reaches the vertical position, the metering range may fluctuate unstablely while the camera is rotated. do not have. Further, the structure for obtaining such a function does not require a special circuit or a complicated interlocking mechanism, so there is no cost disadvantage.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a camera to which an embodiment of the present invention is applied. FIG. 2 is a perspective view of essential parts of an embodiment of the present invention. FIG. 3 is a front view showing the main parts of the embodiment shown in FIG. 2 when the camera is in a horizontal position. Figure 4 shows
It is a schematic diagram of the AA cross section in FIG. 3. Fifth
The figure is a front view showing the state of the main parts in the embodiment shown in FIG. 2 when the camera is in a vertical position. FIG. 6 is a schematic diagram of the BB cross section in FIG. 5. FIG. 7 is an explanatory diagram showing the photometry range when photographing in a horizontal position. FIG. 8 is an explanatory diagram showing the photometry range when photographing in a vertical position. 1...Camera, 3...Fixed lens barrel, 5...Arm, 6...Axis, 7...Aperture plate, 7a to 7c...Through hole, 8...Photodetector, 9...Iron piece, 10... Magnet, 30... Shooting screen, 32... Metering range,
33...Photometering range, 35...Main subject.

Claims (1)

[Scope of utility model registration request] In order to measure the light from the subject, a light receiving element is fixedly provided below the optical axis of the photographic lens, and one end is pivoted above the fixed lens barrel that incorporates the photographic lens. an arm member that rotates due to gravity in the vicinity of the fixed lens barrel; an aperture plate fixed to the other end of the arm member; and an aperture plate formed on the aperture plate to direct the photometry range of the light receiving element toward the bottom of the photographing screen. A diaphragm aperture for horizontal position and two diaphragm apertures for vertical position which are provided at symmetrical positions sandwiching this diaphragm aperture and direct the photometry range toward the center of the photographing screen, and when the camera is in the vertical position, The arm member is allowed to rotate due to gravity so that one or the other of the two vertical aperture apertures is moved to the front of the light receiving element depending on the direction of rotation to the vertical position, and the camera posture is horizontal. In the range before moving from the horizontal position to the vertical position, there is a magnet that restrains the rotation of the arm member by magnetic force and positions the aperture aperture for the horizontal position in front of the light receiving element, and when the arm member rotates due to gravity. 1. A photometry device for a camera, comprising a pair of stoppers that come into contact with an arm member to restrict the end of its rotation, and position one or the other of the vertical aperture openings in front of a light receiving element.