JPH08304875A - Single lens reflex camera - Google Patents

Abstract

PURPOSE: To perform range-finding and the decision of composition without detaching an electrochromic shutter by arranging the shutter utilizing an electrooptical effect between a mirror and photographic film. CONSTITUTION: This camera is provided with a camera body body 1, a lens barrel 2 attached to the body 1 and a photographing lens 3. Then, it is provided with a main mirror 7 having translucency. A part of light transmitted through the lens 3 is reflected, passes through a focusing screen 17 and a pentagonal prism 15 and reaches a finder 16. A photographed image is observed in the finder 16. The light transmitted through the main mirror 7 having the translucency is reflected by a sub mirror 8 and reaches a range-finding part 11. A range- finding optical system is constituted of the main mirror 7 having the translucency, the sub mirror 8 and the range-finding part 11. The shutter 9 utilizing the electrooptical effect is arranged between a film surface 10 and a range-finding system, and has linearly polarizing plates 4 and 5. Since the shutter using linearly polarized light is positioned astern of the range-finding system, natural light is made incident on the main mirror.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-lens reflex camera having a shutter using an electro-optical element or a magneto-optical element.

[0002]

2. Description of the Related Art A single-lens reflex camera having a shutter using an electro-optical element or a magneto-optical element is disclosed in "Photo Industry" VOL46 No. 5 PAGE 63-67 (1
May 988 issue). FIG. 7 shows an outline of a conventional device.

In FIG. 7, 101 is a camera body main body, 102 is a lens barrel mounted on the camera body main body 101, and 103 is a photographing lens. 104 is the first
A linear polarizing plate, and 105 is a second linear polarizing plate. The second linear polarizing plate 105 is arranged so as to be in a crossed Nicol with the first linear polarizing plate 104. Reference numeral 106 denotes PLZT, which is a kind of substance that generates an electro-optical effect, and is arranged between the first linear polarizing plate 104 and the second linear polarizing plate 105. 1
Reference numeral 13 is a power source for applying a voltage to the PLZT 106, and 1
14 is a switch.

The switch 114 is opened and the PLZT 106 is opened.
When no voltage is applied to the first linear polarization plate 104
The linearly polarized light that has passed through passes through the PLZT 106 as it is, and is blocked by the second linearly polarizing plate 106 placed in a crossed Nicols with the first linearly polarizing plate 104 to be in a dark field state. When the switch 114 is closed and a predetermined voltage is applied to the PLZT 106, the linearly polarized light that has passed through the first linearly polarizing plate 104 has its vibrating surface rotated by 90 degrees when passing through the PLZT 106, and the first linearly polarized light has been rotated. The light passes through the second linearly polarizing plate 106 placed in a crossed Nicols with the plate 104 to be in a bright field state.

As described above, the shutter 115 utilizing the electro-optical effect of transmitting or blocking light depending on whether or not a voltage is applied to the PLZT 106 is the first linear polarization plate 104, the PLZT 106 and the second linear polarization. It is constituted by the plate 105. Since the shutter using the electro-optical effect and the shutter using the magneto-optical effect described later use a linear polarizing plate, the transmitted light is linearly polarized light. In the conventional technique, the shutter 115 utilizing the electro-optical effect is attached to the subject side (front side) of the lens barrel 102 as shown in FIG.

Reference numeral 107 denotes a semi-transmissive main mirror, the reflected light of which is a partial polarized light containing a small amount of a linearly polarized light component and is guided to a finder section 116. The transmitted light of the main mirror 107 is partially polarized light containing a large amount of linearly polarized light component, is reflected by the sub mirror 108, and is guided to the distance measuring unit 111.
Main mirror 107, sub mirror 108, and distance measuring unit 11
1, the distance measuring optical system is configured.

An AF driving unit 112 receives a signal from the distance measuring unit 111, rotates the coupling unit 117, and moves the taking lens 103 in a direction parallel to the optical axis to focus the image. Reference numeral 110 is a photographic film. Reference numeral 109 is a mechanical shutter, 109a is a first light shielding member, which is expanded to cover the screen, folded in the storage portion 109b to open the screen, 109c is a second light shielding member, and the first light shielding member 109a
After folding and opening the screen, 109c is stretched to cover the screen.

The conventional device described above is used as follows.

First, the shutter 115 utilizing the electro-optical effect is retracted out of the photographing optical path of the photographing lens 103. For example, the lens barrel 102 is removed. Next, the composition is determined by the finder 116, and the operating member (not shown) of the camera body is operated to measure the distance to the subject by the distance measuring unit 111. Next, the AF drive unit 112 and the coupling unit 117 move the taking lens 103 to bring it into focus. This focused state is held until the end of shooting.

After that, the shutter 115 utilizing the electro-optical effect is attached again to the tip of the lens barrel as shown in FIG. At this time, the shutter 115 is in a dark field state that blocks light. The semi-transparent main mirror 107 and sub-mirror 108 are retracted out of the photographing optical path indicated by the broken line in FIG. 7, and the first light blocking member 109a of the mechanical shutter 109 is folded into the storage section 109b to open the screen. Has not been exposed yet.

Next, the switch 114 is closed for a predetermined time and a voltage is applied to the PLZT to make the shutter 115 utilizing the electro-optical effect a bright field to allow light to pass therethrough to expose the photographic film 110. After exposure, switch 114
Is opened to set the shutter 115 in the dark field to block the photographing light. After that, the second light shielding part material 109c of the mechanical shutter
Is extended to close the screen, the semi-transmissive main mirror 107 and sub-mirror 108 are returned to the positions indicated by the solid lines in FIG. 7, and one image capturing operation is completed.

[0012]

In the above conventional device,
The shutter utilizing the electro-optical effect has to be detached and attached to the lens barrel 102 for each photographing or each distance measurement, which has a drawback that the operation becomes very complicated.

As a method of solving this, distance measurement and distance measurement are performed while the shutter 115 utilizing the electro-optical effect is still attached to the lens barrel 102 and the switch 114 is closed to keep the shutter 115 utilizing the electro-optical effect in the transmitting state. It seems to be good if the composition can be decided. However, this method is quite difficult to implement for the following reasons.

In FIG. 7, the light that has passed through the semi-transparent mirror 107 and travels toward the distance measuring portion 111 has a partial polarization having many linear polarization components even without the shutter 115 utilizing the electro-optical effect. Is. That is, the semi-transmissive main mirror 107 partially has a function of a linearly polarizing plate that produces linearly polarized light.

On the other hand, the shutter 1 utilizing the electro-optical effect
The light transmitted through 15 is the linear polarizing plate as described above. If the vibrating surface of the polarized light passing through the linear polarizing plate 105 and the vibrating surface of the light passing through the semi-transmissive main mirror 107 do not match, almost no light will pass through the semi-transmissive mirror 107, and distance measurement will be performed. Almost no light reaches the portion 111. Therefore, the distance cannot be measured.

Even if the vibrating surface of the light passing through the linear polarization plate 105 and the semi-transmissive main mirror 107 is matched, the light reflected by the semi-transmissive main mirror 107 is reduced. However, there is a drawback that the finder 116 becomes dark and composition cannot be determined.

In any case, in the conventional apparatus, the shutter 115 utilizing the electro-optical effect is provided in the lens barrel 102.
However, the method of attaching to the front of the subject (on the side of the subject) had a serious drawback in that distance measurement and composition determination were not possible at the same time.

The above-mentioned two problems, that is, the shutter utilizing the electro-optical effect must be removed and attached for each photographing or each distance measurement, is troublesome to handle, and distance measurement and composition The fact that decisions cannot be made at the same time is a problem in the conventional technology. The above-mentioned problems commonly occur not only in the shutter utilizing the electro-optical effect but also in the shutter utilizing the magneto-optical effect as long as the conventional technique is used. This is because the shutter using the electro-optical effect or the magneto-optical effect uses a linear polarizing plate.

The present invention has been made in view of the above problems, and an object of the present invention is to enable distance measurement and composition determination without removing and attaching a physical property shutter.

[0020]

In order to achieve this object, a single-lens reflex camera of the present invention has a semi-transmissive mirror which reflects a part of a light beam from a photographing lens and guides it to a finder optical system. 7), a shutter (9) using an electro-optical element or a magneto-optical element arranged between the mirror and the photographic film, and a driving means (13, 14) for driving the shutter.

[0021]

In the single-lens reflex camera having the above structure, the shutter using the electro-optical effect or the magneto-optical effect is arranged between the mirror and the photographing film. It will be located behind the distance optical system. Therefore, natural light, not linearly polarized light, enters the semi-transmissive main mirror, and the light going to the finder optical system and the light going to the distance measuring section are divided appropriately, and the electro-optic effect using linearly polarized light is used. Alternatively, the distance measurement and the composition determination can be performed at the same time by using a shutter using the magneto-optical effect. Further, it is not necessary to remove and attach the shutter for each photographing or each distance measurement, and the camera can be handled easily.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of a single-lens reflex camera according to the present invention.

In FIG. 1, 1 is a camera body,
Reference numeral 2 denotes a lens barrel mounted on the camera body body 1. Reference numeral 3 is a taking lens. The taking lens 3 is originally composed of a large number of lenses, but in this description, one convex lens is represented for simplification. Reference numeral 7 denotes a semi-transmissive main mirror, which reflects a part of the light transmitted through the taking lens 3 so that the focusing screen 17 and the pentaprism 15
After that, it reaches the finder 16. Finder 16
The photographed image can be observed in. Semi-transparent main mirror 7
The light transmitted through is reflected by the sub-mirror 8 and the distance measuring unit 11
To reach. A semi-transparent main mirror 7, a sub-mirror 8 and a distance measuring section 11 constitute a distance measuring optical system.

An AF drive unit 12 receives a signal from the distance measuring unit 11 to rotate the coupling unit 19 to move the taking lens 3 in the optical axis direction. As a result, the photographed image is focused on the film surface 10. Reference numeral 9 denotes a shutter utilizing an electro-optical effect or a magneto-optical effect, which is a film surface 1
0 and the distance measuring optical system. Reference numeral 4 is a first linear polarization plate which constitutes a part of the shutter. Reference numeral 5 is a second linear polarizing plate that forms a crossed Nicols with the first linear polarizing plate 4.
Reference numeral 6 is a substance that is sandwiched between the first linear polarizing plate 4 and the second linear polarizing plate 5 to generate an electro-optical effect or a magneto-optical effect. If 6 is a substance that produces an electro-optical effect, the shutter 9 is a shutter that utilizes the electro-optical effect. If 6 is a substance that produces a magneto-optical effect, the shutter 9 is a shutter that utilizes the magneto-optical effect. In the case of the first embodiment, 6 is PL, which is one of the substances that generate the electro-optical effect.
It is ZT6a. The shutter 9 is a P using the electro-optical effect.
It is an LZT shutter. A power source 13 applies a voltage to the PLZT 6a. 14 is a switch. Switch 1
4 is connected to the power supply unit 13 and the PLZT 6a,
The shutter driving means is constituted by the switch 14 and the switch 14.

FIG. 2 shows the operation of the shutter 9 using the PLZT of the first embodiment.

The natural light A passes through the first linear polarization plate 4 and becomes linearly polarized light having a vibrating surface as shown in FIG. Here, if the switch 14 is turned on and a voltage is applied to the PLZT 6a, the vibrating surface of the linearly polarized light passes through the PLZT 6a while rotating 90 degrees. As a result, the second linear polarization plate placed in the crossed Nicols with respect to the first linear polarization plate can pass through. The shutter 9 has been opened. 〓
If the switch 14 is off, the light that has passed through the first linear polarizing plate 4 and has become linearly polarized light passes through the PLZT 6a while holding its vibrating surface, and becomes a crossed Nicol with the first linear polarizing plate 4. The light is not transmitted because it is blocked by the placed second linear polarization plate. The shutter 9 is closed.

As described above, when the switch 14 is turned on / off, the shutter 9 using PLZT is opened / closed. In the first embodiment, the shutter 9 using PLZT is arranged between the film surface 10 and the distance measuring optical system including the semi-transmissive main mirror 7, the sub mirror 8 and the distance measuring unit 11. It has a feature.

Next, the operation of the camera according to the first embodiment will be described.

First, the composition is determined by the finder 16, and the distance measuring section 11 is operated by operating an operation member (not shown) of the camera body 1 to measure the distance. The AF drive unit 12 receives the signal from the distance measuring unit 11
The taking lens 3 is moved in the optical axis direction via the coupling section 19 to perform focusing. Next, the semi-transmissive main mirror 7 and sub-mirror 8 are retracted to the positions indicated by the broken lines outside the photographing optical path. The switch 14 is turned on for a predetermined time and then turned off. The shutter 9 is opened for a predetermined time to give a predetermined exposure to the film surface 10. next,
The semi-transmissive main mirror 7 and sub-mirror 8 are returned to their original positions (the positions indicated by the solid lines in FIG. 1), and one photographing is completed.

The PLZT described in the first embodiment is a ceramic and can be manufactured relatively easily. Therefore, according to the first embodiment, there is an effect that an inexpensive shutter can be manufactured.

FIG. 3 is a conceptual view showing a shutter using a horizontal Pockels cell according to the second embodiment of the present invention. In the second embodiment, between the first linear polarizing plate 4 and the second linear polarizing plate 5 of the shutter 9, a substance that generates a Pockels effect, which is a kind of electro-optical effect, is used. The Pockels effect is a horizontal Pockels cell that produces an electro-optical effect by applying an electric field in a direction perpendicular to the traveling direction of light, and an electric field that acts in a direction parallel to the traveling direction of light. There is a vertical Pockels cell that occurs. The horizontal Pockels cell is used in the second embodiment, and the vertical Pockels cell is used in the third embodiment described later.

In FIG. 3, the first placed on the crossed Nicols
A Pockels cell 6b is arranged between the linear polarizing plate 4 and the second linear polarizing plate 5. Examples of the substance of the horizontal Pockels cell 6b include crystals of lithium niobate (LiNbO ₃ ) and crystals of lithium tantalate (LiTaO ₃ ). Reference numeral 13 is a power source, and 14 is a switch.
The switch 14 is connected to the power supply unit 13 and the Pockels cell 6b, and the power supply unit 13 and the switch 14 constitute shutter driving means.

The natural light A passes through the first linear polarization plate 4 and becomes linearly polarized light. When the switch 14 is turned on and a predetermined electric field is applied to the horizontal Pockels cell 6b in a direction perpendicular to the traveling direction of light, this linearly polarized light is incident on the Pockels cell 6b, and its vibrating surface is rotated 90 degrees by the Pockels effect. Then, it passes through the Pockels cell 6b. And the first
Second linear polarizing plate 5 placed in a crossed Nicols with linear polarizing plate 4.
Light is transmitted. The shutter has been opened.

Next, when the switch 14 is turned off and no electric field is applied to the horizontal Pockels cell 6b, the light that has passed through the first linear polarizing plate 4 and becomes linearly polarized light has its vibrating surface kept in a constant direction. It passes through the Pockels cell 6b as it is, and is shielded from light by the second linear polarizing plate 5 placed in a Nicol orthogonal to the first linear polarizing plate 4. The shutter is closed.

As described above, the shutter 9 using the horizontal Pockels cell is sandwiched between the first linear polarizing plate 4 and the second linear polarizing plate 5 placed in the Nicols orthogonal to the first linear polarizing plate 4. The horizontal Pockels cell 6b is arranged. The shutter 9 is opened and closed by turning on and off the switch 14.

In the second embodiment of the present invention, as described above, the shutter 9 using the horizontal Pockels cell is used for the distance measurement including the semi-transmissive main mirror 7, sub-mirror 8 and distance measuring section 11. It is characterized in that it is arranged between the optical system and the photographic film 10.

FIG. 4 shows a third embodiment of the present invention, which is a shutter using a vertical Pockels cell 6c. As the material of the vertical Pockels cell 6c, KDP (KH ₂ P
O ₄ crystals) and the like. A pair of transparent electrodes are provided on the front and back of the vertical Pockels cell 6c so that a predetermined electric field can be formed in a direction parallel to the traveling direction of light.

Reference numeral 13 is a power source for applying a predetermined electric field to the vertical Pockels cell 6c, and reference numeral 14 is a switch. The switch 14 is connected to the power supply unit 13 and the vertical Pockels cell 6c, and the power supply unit 13 and the switch 14 constitute a shutter drive means.

When the switch 14 is turned on, the natural light emitted from the light source A passes through the first linear polarization plate 4 and becomes linearly polarized light. After that, when passing through the vertical Pockels cell 6c, the vibration plane of the polarized light is 9
The light passes through a second linearly polarizing plate 5 placed at a crossed Nicols with respect to the first linearly polarizing plate 4 by turning 0 degrees. The shutter is in the opened state. When the switch 14 is turned off and no electric field is applied to the vertical Pockels cell 6c, the light that has passed through the first linear polarizing plate 4 and becomes linearly polarized light is emitted from the Pockels cell 6c with the vibrating surface kept in a constant direction. Pass by
Light is shielded by a second linear polarizing plate 5 placed in a crossed Nicols with respect to the first linear polarizing plate 4. The shutter is closed.

As described above, the shutter 9 using the vertical Pockels cell is sandwiched between the first linear polarizing plate 4 and the second linear polarizing plate 5 placed in the Nicols orthogonal to the first linear polarizing plate 4. The vertical Pockels cell 6c is arranged in a vertical direction. The shutter 9 is opened and closed by turning on and off the switch 14.

In the third embodiment of the present invention, as described above, the shutter 9 using the vertical Pockels cell is composed of the semi-transmissive main mirror 7, sub-mirror 8 and distance measuring section 11. It is characterized in that it is arranged between the distance optical system and the photographing film 10. The vertical Pockels cell has an effect that the rotation angle of polarized light is irrelevant to the cell thickness, so that the Pockels cell can be made thin and the shutter can be miniaturized. There is also an effect that a camera incorporating this shutter can be downsized.

In the second and third embodiments described above, the rotation angle of the linearly polarized light passing through the Pockels cell is proportional to the first power of the applied voltage. There is an effect that the control of the predetermined voltage for turning the rotation becomes easy, and the shutter driving means can be easily configured.

FIG. 5 is a conceptual diagram showing a shutter using a Kersel, which is a fourth embodiment of the present invention. In the fourth embodiment, between the first linear polarizing plate 4 and the second linear polarizing plate 5 of the shutter 9, a substance that generates the Kerr effect, which is a kind of electro-optical effect, is used.

A Kersel 6d is arranged between the first linear polarizing plate 4 and the second linear polarizing plate 5 placed in the crossed Nicols. As substances that generate the Kerr effect (Kersel),
Mixed crystal of potassium niobate and potassium tantalate (KTa
_0.65 Nb _0.35 O ₃ ) and the like. Reference numeral 13 is a power source for applying a predetermined electric field to the car cell, and 14 is a switch. The switch 14 is connected to the power supply unit 13 and the carcell 6d, and the power supply unit 13 and the switch 14 constitute shutter driving means.

When the switch 14 is turned on, the natural light emitted from the light source A passes through the first linear polarizing plate 4 and becomes a linear polarizing plate. After that, when passing through the Kerr cell 6d, the vibrating surface of the polarized light is rotated by 90 degrees by the Kerr effect, and the light passes through the second linear polarizing plate 5 placed in the Nicol orthogonal to the first linear polarizing plate 4. The shutter is in the opened state. When the switch 14 is turned off and no electric field is applied to the Kersel 6d, the light that has passed through the first linear polarization plate 4 and becomes linearly polarized light passes through the Kersel 6d with the vibrating surface kept constant, and The light is shielded by a second linear polarizing plate 5 placed in a crossed Nicols with the linear polarizing plate 4. The shutter is closed.

As described above, the shutter 9 utilizing the Kerr effect is arranged by sandwiching the first linear polarizing plate 4 and the second linear polarizing plate 5 placed in the Nicols orthogonal to the first linear polarizing plate 4. It is composed of a car cell 6d. Switch 1
The shutter 9 is opened and closed by turning on and off 4. The Kerr effect is different from the above-mentioned Pockels effect in that the turning angle of the linearly polarized light is proportional to the square of the electric field acting on the Kerr cell, and the direction of the electric field acting has no polarity. There is an effect that a shutter having excellent properties can be obtained.

The fourth embodiment of the present invention is a shutter 9 utilizing the Kerr effect which is one of the electro-optical effects as described above.
Is a semi-transmissive main mirror 7, a sub-mirror 8 and a distance measuring unit 11, and a photographic film 10.
It is characterized by being placed between and.

Next, a fifth embodiment of the present invention will be described.

As described in the first to fourth embodiments, there are shutters using the electro-optical effect, those using PLZT, those utilizing the Pockels effect, those utilizing the Kerr effect, and the like. In addition, there is also one utilizing the electro-optical effect of liquid crystal. The fifth embodiment of the present invention utilizes the electro-optical effect of this liquid crystal. Note that the shutter using liquid crystal also uses linearly polarized light, like other shutters using the electro-optical effect, and is not shown.

That is, the shutter 9 is formed by sandwiching the liquid crystal 6e having an electro-optical effect between the first linear polarizing plate 4 and the second linear polarizing plate 5 placed in the Nicols orthogonal to the first linear polarizing plate 4.
When the switch 14 of the shutter driving means is turned on, the shutter 9 is opened, and when the switch 14 is turned off, the shutter 9 is opened.
Closes.

Since the shutter using liquid crystal has a low driving voltage, there is an effect that the power source section 13 of the shutter driving means can be easily constructed. Therefore, there is an effect that the configuration of a camera incorporating this becomes simple.

In the fifth embodiment of the present invention, a shutter 9 using a liquid crystal, a distance measuring optical system composed of a semi-transmissive main mirror 7, a sub mirror 8 and a distance measuring section 11, and a photographing film 10 are used. It is characterized by being placed between and.

As described in the first to fifth embodiments, the shutter 9 using the electro-optical effect includes the first linear polarizing plate 4 and the second linear polarizing plate 5 placed in a crossed Nicols.
And a substance 6 having an electro-optical effect is sandwiched between them.

A PLZ is used for the shutter utilizing the electro-optical effect.
There are those that use T, those that use the Pockels effect, those that use the Kerr effect, those that use liquid crystal, etc.
All of them utilize the action of linearly polarized light. One of the features of the present invention is that the shutter utilizing the electro-optical effect as described above is arranged between the distance measuring optical system and the photographing film in the single-lens reflex camera.

In addition to the shutter utilizing the electro-optical effect as described above, there is a shutter utilizing the magneto-optical effect.

FIG. 6 is a sixth embodiment of the present invention and shows the construction of a shutter utilizing the Faraday effect which is a kind of magneto-optical effect.

Reference numeral 4 is a first linear polarizing plate, and 5 is a second linear polarizing plate placed in a crossed Nicols with the first linear polarizing plate. 6
f is a Faraday cell that produces a Faraday effect when a magnetic field is applied in parallel with the traveling direction of light, and is made of lead glass or the like. A coil 18 is wound around the Faraday cell 6f to generate a magnetic field.

The shutter 9 using the Faraday effect is the first
The linear polarizing plate 4, the Faraday cell 6f for generating the Faraday effect, such as lead glass, arranged between the second linear polarizing plates 5 and 4 and 5, and the coil 18 for applying a magnetic field. It is configured.

Reference numeral 13 is a power supply for supplying a current to the coil 18 to generate a predetermined magnetic field, and 14 is a switch. The switch 14 is connected to the power supply unit 13 and the coil 18. The power supply unit 13 and the switch 14 constitute shutter drive means.

When the switch 14 is turned on, the light source A
The natural light emitted from the first light passes through the first linear polarization plate 4 to become linearly polarized light, and enters the Faraday cell 6f. Since the switch 14 is turned on, a current is flowing through the coil 18 and a predetermined magnetic field acts on the Faraday cell 6f. Therefore, the linearly polarized light incident on the Faraday cell 6f is emitted from the Faraday cell 6f with its vibrating surface rotated by 90 degrees by the Faraday effect. This linearly polarized light passes through a second linearly polarizing plate 5 arranged in a crossed Nicols with the first linearly polarizing plate 4. The shutter 9 has been opened. When the switch 14 is turned off, the light that has passed through the first linear polarization plate 4 and becomes linearly polarized light passes through the Faraday cell 6f while holding its vibrating surface. Then, the light is shielded by the second linear polarizing plate 5 placed in a crossed Nicols with the first linear polarizing plate 4. The shutter 9 is closed. As described above, the switch 14 is turned on
When turned off, the shutter 9 opens and closes.

Since the shutter using the Faraday effect as described above has a simple structure, there is an effect that it has few failures and is excellent in reliability. A camera incorporating this also has the effect of being highly reliable.

The sixth embodiment of the present invention comprises a shutter 9 utilizing the Faraday effect, a distance measuring optical system including a semi-transmissive main mirror 7, a sub mirror 8 and a distance measuring section 11.
It is characterized in that it is arranged between the photographic film 10.

As described above, some shutters utilizing the magneto-optical effect utilize the Faraday effect, and utilize the action of linearly polarized light.

The second feature of the present invention resides in that the shutter utilizing the magneto-optical effect as described above is arranged between the distance measuring optical system and the photographing film in the single-lens reflex camera.

According to the embodiment described above, a shutter utilizing the electro-optical effect using the action of linearly polarized light or the magneto-optical effect is provided between the distance measuring optical system of the single-lens reflex camera and the photographing film. Since it is placed, the light that passes through the shooting lens becomes natural light, and it is distributed to the finder optical system and the distance measuring optical system by the semi-transparent main mirror, and the camera is equipped with a shutter that uses linearly polarized light. However, there is an effect that distance measurement and composition determination can be performed at the same time.

According to the first, second, third, fourth and sixth embodiments, a shutter utilizing the electro-optical effect or the magneto-optical effect having a fast response can be incorporated in the single-lens reflex camera, There is also an effect that a camera having a remarkably high shutter speed can be realized.

Further, since the shutter utilizing the electro-optical effect or the magneto-optical effect having no mechanical operation part can be incorporated in the single-lens reflex camera, there is also an effect that a durable and durable camera can be realized. . Further, there is an effect that a single-lens reflex camera capable of synchronizing all shutter speeds X can be realized.

[0069]

As described above, according to the single-lens reflex camera of the present invention, the shutter using the electro-optical element or the magneto-optical element is arranged between the semitransparent mirror and the photographic film. I have to. This allows
Natural light, not linearly polarized light, is incident on the semi-transparent main mirror, and the light traveling to the finder optical system and the light traveling to the distance measuring section are appropriately divided, and any one of them does not drop out. Therefore, it is possible to perform distance measurement and composition determination at the same time without removing and attaching the physical property shutter.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a single-lens reflex camera according to the present invention.

FIG. 2 is a conceptual diagram showing a first embodiment of a single-lens reflex camera according to the present invention.

FIG. 3 is a conceptual diagram showing a second embodiment of the single-lens reflex camera according to the present invention.

FIG. 4 is a conceptual diagram showing a third embodiment of the single-lens reflex camera according to the present invention.

FIG. 5 is a conceptual diagram showing a fourth embodiment of the single-lens reflex camera according to the present invention.

FIG. 6 is a conceptual diagram showing a sixth embodiment of the single-lens reflex camera according to the present invention.

FIG. 7 is a sectional view showing an example of a conventional single-lens reflex camera having a shutter using an electro-optical element or a magneto-optical element.

[Explanation of symbols]

 1 Camera Body 3 Photographic Lens 6 Material 6a PLZT 6b Horizontal Pockels Cell 6c Vertical Pockels Cell 6d Cassel 6e Liquid Crystal 6f Faraday Cell 7 Main Mirror 8 Submirror 9 Shutter 10 Photographic Film 11 Range Finder 12 AF Drive 13 Switch Power Supply 14 15 pentaprism 16 viewfinder 17 focusing screen 18 coil 19 coupling section

Claims (7)

[Claims] 1. A semi-transmissive mirror that reflects a part of a light beam from a photographing lens and guides it to a finder optical system, and an electro-optical element or a magneto-optical element arranged between the mirror and the photographing film. A single-lens reflex camera comprising: a shutter used and a drive unit for driving the shutter. 2. The single-lens reflex camera according to claim 1, wherein the electro-optical element is PLZT. 3. The single-lens reflex camera according to claim 1, wherein the electro-optical element is an electro-optical element utilizing a Pockels effect. 4. The single-lens reflex camera according to claim 1, wherein the electro-optical element is an electro-optical element utilizing a Kerr effect. 5. The single-lens reflex camera according to claim 1, wherein the electro-optical element is liquid crystal. 6. The single-lens reflex camera according to claim 1, wherein the magneto-optical element is a magneto-optical element utilizing a Faraday effect. 7. The single-lens reflex camera according to claim 1, wherein the shutter is provided between the mirror and the photographic film in the vicinity of the mirror.