JPH0990532A - Stop and shutter speed measuring device for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the operations of a stop and a shutter from the outside of a camera. SOLUTION: The camera is provided with a light projecting means for projecting spot light A polarized roughly aligning with an optical axis, toward the lens system 10 of a camera main body from the side of an object outside the camera main body and a light receiving means such as a polarizing filter 20 for leading reflected light B, that is, the light diffused/reflected on a film surface 16 of the spot light A projected by the light projecting means, to the outside of the camera main body with the lens system 10 and removing a component polarized in the same direction as the polarization direction, projected by the light projecting means, in the reflected light B, to receive it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device for measuring the performance of a camera diaphragm and shutter speed.

[0002]

2. Description of the Related Art The aperture and shutter speed of a camera define important photographing conditions. Therefore, in the product inspection of the camera, it is checked whether the aperture and the shutter speed are controlled as set in advance. The conventional method of inspecting the aperture and shutter speed of a camera is to make light incident on the camera from the subject side, place a light receiving element on the film surface, and detect light that has passed through the aperture and shutter by the light receiving element. It was a method of detecting the amount of light passing through the shutter.

The amount of light passing through the diaphragm and shutter is
The total amount of light when the shutter opens and closes once depends on the aperture of the diaphragm and the time that the shutter opens and closes.
It is an integral of the time the shutter is open and closed. The above inspection method is to inspect by detecting light with a light receiving element placed on the film surface to detect whether or not a light receiving amount according to a predetermined diaphragm and shutter speed can be obtained.

In this way, the method of detecting whether or not the aperture and the shutter are controlled according to the specified values is a lens shutter having the functions of the aperture and the shutter even in the case of the model in which the aperture and the shutter are provided separately. The same is true for. In the case of a lens shutter, since the opening area of the shutter portion changes as the shutter opens and closes, the amount of incident light changes with time.

[0005]

By the way, when the light receiving element is set on the film surface for inspection as described above,
In order to exchange and set the film, the back cover provided in the camera body is opened and the light receiving element is set at the film surface position. However, there is a demand for an apparatus that can perform inspection without opening the back cover.

The present invention has been made on the basis of such a background, and an object thereof is to set a diaphragm and a shutter of a camera to a predetermined standard regardless of a method of arranging a light receiving element on a film surface position. An object of the present invention is to provide a device for measuring a diaphragm and a shutter speed of a camera, which can suitably inspect and measure whether or not it is controlled according to conditions.

[0007]

The present invention has the following constitution in order to achieve the above object. That is, the light projecting means for projecting the spot light polarized from the object side outside the camera body toward the lens system of the camera body so as to be substantially aligned with the optical axis, and the spot light projected by the light projecting means. The reflected light diffusely reflected on the film surface is guided to the outside of the camera body through the lens system, and the reflected light is removed by removing the polarized component in the same direction as the polarized direction projected by the light projection means from the reflected light. And a light receiving means for receiving the light.

Further, linearly polarized light is used as the spot light, and the light receiving means makes 90 ° between the linearly polarized light and the polarization direction.
The polarization filter is installed in a deviated arrangement. As a result, the ghost light caused by the spot light in the reflected light can be suitably removed, and reliable measurement becomes possible. Further, as the spot light, a light flux having a diameter smaller than the aperture diameter of the diaphragm and the shutter is used. When linearly polarized laser light is used as the spot light, it is possible to obtain high-quality light having a small diameter and a high degree of polarization. Further, in front of the lens system, the spot light projected by the light projection means is transmitted to the film surface side, and diffusely reflected by the film surface,
It is characterized in that a shutter, a diaphragm, a half mirror for reflecting light passing through the lens system to the light receiving side are arranged, and a polarizing filter, a condenser lens, and a light receiving element are arranged in this order on the light receiving side.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing an embodiment of a diaphragm and shutter speed measuring device according to the present invention. A diaphragm and shutter speed measuring device according to the present invention projects spot light onto a film surface from a subject side to a camera body through a lens system of the camera, and diffuses and reflects light on the film surface to the camera through the lens system. The feature is that the aperture and shutter speed are measured by detecting the outside of the main body.

When the spot light A is projected from the subject side onto the lens system 10 of the camera body, the spot light A is made to substantially coincide with the optical axis of the lens system 10 as shown in FIG. This is because the light is surely diffused and reflected on the film surface 16 by allowing the light to pass through the diaphragm 12 and the shutter 14 so that the opening / closing action of the diaphragm 12 and the shutter 14 can be reliably detected.

As shown in FIG. 1, a half mirror 18 is installed outside the camera body in front of the lens system 10, and a diaphragm 12, a shutter 14, and a film surface 16 are arranged behind the lens system 10 in the camera body. To do. The lens system 10 is shown in a simplified manner with one lens in the drawing.

The half mirror 18 transmits the spot light A and makes it enter the lens system 10, and at the same time, the film surface 1
The light reflected by 6 and transmitted through the lens system 10 is guided to the light receiving system. In the present embodiment, linearly polarized laser light is used as the spot light A projected by the light projection means, and the light receiving system is configured to detect a linearly polarized light component having a 90 ° polarization direction different from that of the spot light A. And For example, horizontally polarized light is incident as the spot light A, and vertically polarized light is received in the light receiving system.

In FIG. 1, the polarization filter 20 arranged on the light receiving system side of the half mirror 18 is a polarization filter which transmits vertically polarized light. The polarizing filter 20 is provided for the purpose of passing the vertical component of the linearly polarized light and removing the horizontal linearly polarized light. Reference numeral 22 is a condenser lens, 24 is a light receiving element, and 26 is an amplifier.

According to the measuring device having the above structure, it is possible to inspect whether or not the diaphragm and the shutter speed are controlled in accordance with predetermined standard conditions by the following operation. That is, the horizontally polarized spot light A is incident from the outside of the camera body toward the lens system 10 so as to match its optical axis. The spot light A passes through the shutter 14 when the shutter 14 opens, and the spot light A
Is projected to

The spot light A is diffusely reflected (diffuse reflected) on the film surface 16 and reflected toward the shutter 14.
The incident spot light A is horizontally polarized, while the reflected light B has a random polarization component due to irregular reflection on the film surface 16. The reflected light B passes through the shutter 14 and the diaphragm 12 while the shutter 14 is open. Since the film surface 16 is at the focal position with respect to the lens system 10, it passes through the lens system 10 to become parallel light, and the half mirror 18 Is reflected toward the polarization filter 20, passes through the polarization filter 20, is condensed by the condenser lens 22, and is detected by the light receiving element 24. The detection signal of the light receiving element 24 is amplified by the amplifier 26,
It is output as a light reception signal.

Since the polarization filter 20 passes only the vertical component of the linearly polarized light, the horizontal linearly polarized light is completely cut by the polarization filter 20 and is not detected by the light receiving element 24. As described above, the reason why the polarization filter 20 is deviated by 90 ° with respect to the polarization direction of the spot light A is that the influence of the incident light is removed from the light detected by the light receiving element 24 as much as possible, and the diaphragm 12 is adjusted by the reflected light B. This is so that the action of the shutter 14 can be accurately detected.

When the spot light A enters the camera,
Various ghost light is generated by being reflected by the half mirror 18, the lens system 10, the diaphragm 12, the shutter 14, and the like. The polarizing filter 20 is effective in removing such ghost light, reliably detecting the action of the reflected light B passing and being blocked by the shutter 14 and the diaphragm 12, and reducing optical noise to enable reliable inspection. Target. The spot light A
As described above, the method of detecting reflected light by simply entering laser light without using polarized light causes a lot of optical noise, and accurate measurement is difficult.

Since the reflected light on the film surface 16 is scattered isotropically, the amount of light detected by the light receiving element 24 reflects the aperture diameter (area) when the shutter 14 is opened and the aperture diameter 12 of the diaphragm 12. It will be what you did. That is, the light receiving element 24
The detection signal at 1 can be obtained as output data according to the opening / closing operation of the shutter 14, as shown in FIG.
Then, by integrating this output data, it is possible to measure the amount of received light in one shutter opening / closing operation, and by comparing this with the data set as standard conditions in advance, it is possible to judge the quality.

In this way, the amount of light received by the shutter speed when the diaphragm 12 is set to a predetermined diaphragm value can be measured, and it is judged whether or not the product to be inspected meets the specified condition. In addition to the model having the diaphragm 12 and the shutter 14 as separate bodies as described above, the present measuring apparatus is similarly applied to a model having a shutter that also serves as a diaphragm, such as a lens shutter. Also in this case, the film surface 1
The light reflected by 6 is detected as an integrated value in the light receiving element 24 with the opening and closing of the shutter, and the accurate amount of received light by opening and closing the shutter once is detected.

The above-described embodiment of the aperture and shutter speed measuring device detects the action of the aperture or the shutter by causing the spot light A to enter the camera from the outside of the camera body. There is an advantage that measurement can be performed by completely remote operation without the need to set the element. This enables product inspection and measurement without opening the back cover of the camera body.

Although horizontal polarization is used as the spot light A in the above embodiment, the spot light A incident in the opposite direction may be vertical polarization and the polarizing filter 20 may be arranged to pass horizontal polarization. Good. Further, as long as the arrangement is such that the polarization direction of the incident light and the direction of the polarization filter are deviated by 90 °, the arrangement is not particularly limited to the horizontal or vertical arrangement. In addition, normally, the incident light and the light receiving side polarization filter 20
It is preferable to dispose the polarization directions different by 90 ° from each other in order to reduce optical noise, but it is preferable even if the incident side and the light receiving side are not completely different by 90 ° depending on the arrangement of the optical system. There may be a condition. Alternatively, the incident light may be circularly polarized light or elliptically polarized light instead of linearly polarized light, and the clockwise light and the counterclockwise polarized light are distinguished and detected to detect the reflected light B from the film surface 16. It is possible.

Although laser light is used as the incident light in the above example, it may not be laser light as long as polarized light can be used. Further, although spot light having a smaller diameter than the aperture diameters of the diaphragm 12 and the shutter 14 is used as the incident light in the above example, a light beam larger than the aperture diameters of the diaphragm 12 and the shutter 14 can be used depending on the case.

When the spotlight A is incident on the camera, it must be arranged so that the incident light passes through the diaphragm 12 and the shutter 14 and strikes the film surface 16 as described above. When a laser beam is used as the incident light, the luminous flux is thin, so the diaphragm 12 and the shutter 1 are not always necessary.
The light can be made incident on the film surface 16 even if it does not coincide with the center of the opening surface of No. 4, but the incident light must be incident as accurately as possible because the diaphragm 12 may be narrowed down for measurement.

In the embodiment shown in FIG. 1, a position detecting sensor 28 for recognizing the image of the diaphragm 12 is provided behind the condenser lens 22, and a detecting device 30 for detecting the positional deviation of the incident light by the output of the position detecting sensor 28. Was set up. The optical arrangement of the position detection sensor 28 is such that a half mirror is provided in front of the position detection sensor 28 and the image of the diaphragm 12 is recognized at the focal position. Position detection sensor 28 and detection device 30
When the deviation of the image of the diaphragm 12 from the normal position is detected by, the light source 32 that projects the spot light A is adjusted to correct the projection position of the spot light A to the normal position. In this case, instead of adjusting the light source 32, the position of the camera of the object to be inspected can be adjusted and corrected.

FIG. 2 shows another embodiment in which the image of the diaphragm 12 is recognized to detect the positional deviation of incident light. In the case of the embodiment shown in FIG. 1 as well, it is possible to recognize the image of the diaphragm 12 and detect the positional deviation of the incident light, but in the configuration of FIG. 1, the position detection sensor 28 is at the focal position of the lens 22. ,
When the diaphragm 22 is displaced, the amount of displacement does not appear so large that the displacement may not always be detected accurately. On the other hand, in the embodiment shown in FIG. 2, the parallel light that has passed through the polarization filter 20 is guided to the position detection sensor 28 as it is by a half mirror provided in front of the position detection sensor 28, whereby the positional deviation of the diaphragm 12 is further increased. It is possible to detect with accuracy. In FIG. 2, the condenser lens 2
However, the condenser lens 22 may be arranged between the light receiving element 24 and the half mirror.

[0026]

As described above, according to the camera aperture and shutter speed measuring device of the present invention, the action of the aperture and shutter is detected and measured by projecting polarized light from the outside of the camera to the inside of the camera. As a result, there is no need to set a light receiving element inside the camera as in the conventional case, and the aperture and shutter speed can be measured very easily and reliably with high accuracy.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of an embodiment of a camera aperture and shutter speed measuring device.

FIG. 2 is an explanatory diagram showing a configuration of another embodiment of a camera aperture and shutter speed measuring device.

[Explanation of symbols]

 10 Lens system 12 Aperture 14 Shutter 16 Film surface 18 Half mirror 20 Polarizing filter 22 Condensing lens 24 Light receiving element 26 Amplifier

Claims (5)

[Claims] 1. A light projecting means for projecting a spot light polarized from a subject side outside the camera body toward a lens system of the camera body so as to be substantially coincident with an optical axis, and projected by the light projecting means. The reflected light, which is the diffused and reflected spot light on the film surface, is guided to the outside of the camera body through the lens system, and the polarized component in the same direction as the polarized direction projected by the light projection means is removed from the reflected light. And a light receiving means for receiving reflected light. 2. The camera according to claim 1, wherein linearly polarized light is used as the spot light, and the light receiving means is provided with a polarizing filter with an arrangement in which the polarization direction is deviated by 90 ° from the linearly polarized light. Aperture and shutter speed measuring device. 3. A diaphragm and shutter speed measuring device for a camera according to claim 1, wherein a light flux having a diameter smaller than an aperture diameter of the diaphragm and the shutter is used as the spot light. 4. The camera aperture and shutter speed measuring device according to claim 1, wherein linearly polarized laser light is used as the spot light. 5. The front side of the lens system transmits the spot light projected by the light projecting unit to the film surface side, and the light diffused and reflected by the film surface and passing through the shutter, diaphragm and lens system is on the light receiving side. 5. A half mirror which reflects light is arranged, and a polarizing filter, a condenser lens, and a light receiving element are arranged on the light receiving side in this order.
A camera aperture and shutter speed measuring device as described above.