JP2008085887A - Imaging system, camera system, camera body, and imaging system control method - Google Patents

Abstract

An imaging system capable of realizing a focus detection function in an optical finder mode and an electronic finder mode and a control method thereof are provided.
A camera system includes a camera body and an interchangeable lens that can be attached to and detached from the camera body. The interchangeable lens 2 has an imaging optical system L that forms light from the imaging optical system. The camera body 3 includes an imaging unit 71, a finder optical system 19 for confirming light from the imaging optical system from the outside, an image display unit 72 for displaying an image of a subject obtained by the imaging unit 71, and an imaging optical system. The first mirror 60 that guides the light to the finder optical system 19, the second mirror 61 that guides the light from the imaging optical system to the imaging unit 71, and focus detection that detects the focal point using the light from the imaging optical system L Part 5 and body microcomputer 12 for controlling the operation of each part.
[Selection] Figure 2

Description

  The present invention relates to an imaging system and a control method thereof, and more particularly to an imaging system capable of switching between an optical finder mode and an electronic finder mode and a control method thereof.

2. Description of the Related Art Conventionally, a digital single-lens reflex camera in which an image sensor is arranged on a film traveling portion of a silver salt single-lens reflex camera is known. Since users can use assets such as interchangeable lenses from the silver salt era, the market has grown with great support. Furthermore, the image pickup device format is also developed in various ways such as 4/3 inch, APS-C, and 35 mm full size. For this reason, the choices of users are expanding and the growth is expected more and more.
However, with rapid digitalization, manufacturers have not yet developed digital single-lens reflex camera systems. For this reason, what diverted the silver salt single-lens reflex system is commercialized, and it is difficult to propose a completely new system.
Therefore, in order to realize an electronic viewfinder mode (live view display) unique to digital cameras, we proposed a shooting system that raises the main mirror of the silver salt single lens reflex camera, guides the subject image to the image sensor, and displays the subject image on the display. Has been.
JP 2001-125173 A JP 2005-277777 A

However, in the imaging system described in Patent Document 1, although live view display is possible, for example, introduction of a subject image into a phase difference detection AF (autofocus) module having a focus detection function is also blocked. . For this reason, focus adjustment cannot be performed in the electronic viewfinder mode, and the main mirror must be inserted once and the focus adjustment must be performed again at the time of shooting. As a result, in the photographing system described in Patent Document 1, the release time lag that occurs between when the photographer presses the release button and when the photographing operation is actually started increases, and the photographer feels very uncomfortable with the photographing operation. To remember. In addition, such a photographing system has a high possibility of missing a photo opportunity.
Further, in the photographing system described in Patent Document 2, a module for focus detection is not described, and a photographed image is guided to the optical viewfinder by one total reflection double-sided mirror. For this reason, in the electronic finder mode, when the focus detection unit is arranged, light from the imaging optical system is blocked in the middle of the optical path, and it is difficult to realize the focus detection function.
As described above, in the photographing system capable of switching between the optical finder mode and the electronic finder mode, it is difficult to realize the focus detection function in both modes.
It is an object of the present invention to provide a photographing system, a camera system, a camera body, and a photographing system control method capable of realizing a focus detection function in an optical finder mode and an electronic finder mode.

An imaging system according to a first invention is an imaging system for imaging a subject, and an imaging optical system that captures light from the subject, and an image of the subject by performing photoelectric conversion on the light from the imaging optical system. An imaging unit to be acquired, an observation optical system for confirming light from the imaging optical system from the outside, an image display unit for displaying an image of a subject obtained by the imaging unit, and optical light for observation from the imaging optical system A first mirror that leads to the system; a second mirror that guides light from the imaging optical system to the imaging unit; and a focus detection unit that detects a positional relationship between the focus of the imaging optical system and the subject.
In this photographing system, light from a subject is captured by an imaging optical system, and light from the imaging optical system is guided to an observation optical system by a first mirror and guided to an imaging unit by a second mirror. When light from the imaging optical system is guided to the observation optical system by the first mirror, the photographer can check the subject by the observation optical system (optical viewfinder mode). On the other hand, when light from the imaging optical system is guided to the imaging unit by the second mirror, the image of the subject acquired by the imaging unit is displayed on the image display unit, and the photographer confirms the subject by the image display unit. (Electronic viewfinder mode).
At this time, for example, when the first and second mirrors are semi-transmissive mirrors, a state where light from the imaging optical system is incident on the observation optical system and a state where light from the imaging optical system is incident on the imaging unit Thus, a part of the light from the imaging optical system can be incident on the focus detection unit. That is, in this photographing system, the focus detection function can be realized in the optical finder mode and the electronic finder mode.

Here, the “shooting system” includes a system for shooting a still image or a moving image of a subject such as a digital still camera or a digital video camera.
An imaging system according to a second invention is the imaging system according to the first invention, wherein the first mirror directs light from the imaging optical system to the observation optical system and a first retraction facing the observation optical system. It can move between positions. The second mirror is movable between a second insertion position that guides light from the imaging optical system to the imaging unit and a second retraction position that faces the imaging unit.
Thereby, the light from the imaging optical system can be guided only to either the observation optical system or the imaging unit.
An imaging system according to a third invention is the imaging system according to the second invention, wherein the observation optical system has an incident optical axis perpendicular to the optical axis of the imaging optical system, and the incident light from the imaging optical system is incident Has a surface. The image pickup unit has an image pickup element including a light receiving surface that performs photoelectric conversion on the light from the image pickup optical system and is disposed to face the incident surface across the optical axis of the image pickup optical system. The first mirror has a first reflecting surface facing the incident surface at the first retracted position. The second mirror has a second reflecting surface facing the light receiving surface at the second retracted position.
An imaging system according to a fourth invention is the imaging system according to any one of the first to third inventions, wherein the first mirror is opposite to the imaging optical system across the optical path from the first mirror to the observation optical system. Has a first rotation axis. The second mirror has a second rotation axis that is disposed on the opposite side of the imaging optical system across the optical path from the second mirror to the imaging unit.

In this case, the optical finder mode and the electronic finder mode can be switched by changing the angles of the first and second mirrors around the first and second rotation axes.
An imaging system according to a fifth invention is the imaging system according to any one of the first to fourth inventions, wherein the first mirror is a semi-transmissive mirror. The focus detection unit is disposed outside the movable range of the first and second mirrors and at a position where light from the imaging optical system that passes through the first mirror enters.
In this case, part of the light from the imaging optical system passes through the first mirror and enters the focus detection unit. For this reason, when contrast-type focus detection is performed using the imaging unit in the electronic finder mode, focus detection can be performed in the optical finder mode and the electronic finder mode.
According to a sixth aspect of the present invention, in the photographing system according to any one of the first to fifth aspects, the focus detection unit divides the subject image from the detection element and the imaging optical system and divides the image into the detection element. A separator lens for imaging, and a concave condenser lens that guides light from the imaging optical system to the separator lens.
In this case, focus detection can be performed by the phase difference detection method.

An imaging system according to a seventh invention is the imaging system according to the fifth invention, wherein the second mirror is a semi-transmissive mirror.
In this case, part of the light from the imaging optical system passes through the second mirror and enters the focus detection unit. For this reason, focus detection is possible in the optical finder mode and the electronic finder mode. Further, when the focus detection unit adopts the phase difference detection method, focus detection with the same accuracy as in the optical finder mode can be performed in the electronic finder mode.
An imaging system according to an eighth aspect is the imaging system according to the seventh aspect, wherein the first mirror and the second mirror have substantially the same thickness. The first mirror and the second mirror have substantially the same tilt angle with respect to the incident optical axis at the first and second insertion positions.
As a result, the optical path lengths of the subject images transmitted through the first mirror and the second mirror are equalized, and it is possible to focus with a common focus detection unit. For this reason, it is possible to obtain the same focus detection accuracy in the optical finder mode and the electronic finder mode.
An imaging system according to a ninth aspect is the imaging system according to the fifth aspect, wherein the second mirror is a total reflection mirror. The imaging system further includes a second focus detection unit that detects the positional relationship between the focus of the imaging optical system and the subject using the imaging unit.

In this case, in the electronic finder mode, focus detection can be performed by, for example, a contrast detection method using an imaging unit. For this reason, for example, the conventional video AF can be used at the time of moving image shooting using a live view, and very smooth focus adjustment is possible.
An imaging system according to a tenth aspect of the invention is the imaging system according to any one of the first to ninth aspects, further comprising a mirror drive control unit that controls driving of the first and second mirrors. The mirror drive control unit drives the first and second mirrors so that light from the imaging optical system is incident on only one of the first and second mirrors.
An imaging system according to an eleventh aspect of the invention is the imaging system according to the second aspect of the invention, further comprising a mirror drive control unit that controls driving of the first and second mirrors. In the optical viewfinder mode in which light from the imaging optical system is guided to the observation optical system, the mirror drive control unit drives the second mirror to the second retracted position and drives the first mirror to the first insertion position. In the electronic finder mode in which light from the imaging optical system is guided to the imaging unit, the mirror drive control unit drives the first mirror to the first retracted position and drives the second mirror to the second insertion position.
A camera system according to a twelfth aspect of the invention is a camera system for photographing a subject, which is a camera system for photographing a subject, and includes an interchangeable lens and a camera body to which the interchangeable lens can be attached and detached. The interchangeable lens has an imaging optical system that captures light of a subject. The camera body includes an imaging unit that acquires an image of a subject by performing photoelectric conversion on light from the imaging optical system, an observation optical system for confirming light from the imaging optical system from the outside, and an imaging unit. An image display unit that displays the acquired image of the subject, a first mirror that guides light from the imaging optical system to the observation optical system, a second mirror that guides light from the imaging optical system to the imaging unit, and an imaging optical system A focus detection unit that detects a positional relationship between the focus and the subject.

In this camera system, light from a subject is captured by an imaging optical system, and light from the imaging optical system is guided to an observation optical system by a first mirror and guided to an imaging unit by a second mirror. When light from the imaging optical system is guided to the observation optical system by the first mirror, the photographer can check the subject by the observation optical system (optical viewfinder mode). On the other hand, when light from the imaging optical system is guided to the imaging unit by the second mirror, the image of the subject acquired by the imaging unit is displayed on the image display unit, and the photographer confirms the subject by the image display unit. (Electronic viewfinder mode).
At this time, for example, when the first and second mirrors are semi-transmissive mirrors, a state where light from the imaging optical system is incident on the observation optical system and a state where light from the imaging optical system is incident on the imaging unit Thus, a part of the light from the imaging optical system can be incident on the focus detection unit. That is, in this camera system, the focus detection function can be realized in the optical finder mode and the electronic finder mode.
A camera body according to a thirteenth aspect of the present invention is a camera body that is used in a camera system for photographing a subject together with an interchangeable lens having an imaging optical system that takes light from the subject, and the interchangeable lens is detachable. The camera body includes an imaging unit that acquires an image of the subject by performing photoelectric conversion on light from the imaging optical system, an observation optical system for confirming light from the imaging optical system from the outside, and imaging An image display unit that displays an image of the subject acquired by the unit, a first mirror that guides light from the imaging optical system to the observation optical system, a second mirror that guides light from the imaging optical system to the imaging unit, and imaging A focus detection unit that detects a positional relationship between the focus of the optical system and the subject.

In this camera body, light from the imaging optical system of the interchangeable lens is guided to the observation optical system by the first mirror and guided to the imaging unit by the second mirror. When light from the imaging optical system is guided to the observation optical system by the first mirror, the photographer can check the subject by the observation optical system (optical viewfinder mode). On the other hand, when light from the imaging optical system is guided to the imaging unit by the second mirror, the image of the subject acquired by the imaging unit is displayed on the image display unit, and the photographer confirms the subject by the image display unit. (Electronic viewfinder mode).
At this time, for example, when the first and second mirrors are semi-transmissive mirrors, a state where light from the imaging optical system is incident on the observation optical system and a state where light from the imaging optical system is incident on the imaging unit Thus, a part of the light from the imaging optical system can be incident on the focus detection unit. That is, in this camera body, a focus detection function can be realized in the optical finder mode and the electronic finder mode.
According to a fourteenth aspect of the present invention, there is provided a photographing system control method comprising: an imaging optical system that captures light from a subject; an observation optical system for confirming light from the imaging optical system from the outside; and a subject acquired by an imaging unit. An image display unit that displays an image, a first mirror that guides light from the imaging optical system to the observation optical system, a second mirror that guides light from the imaging optical system to the imaging unit, a focus of the imaging optical system, and a subject And a mirror drive control unit that controls the driving of the first and second mirrors. The first mirror is movable between a first insertion position that guides light from the imaging optical system to the observation optical system and a first retraction position that faces the observation optical system. The second mirror is movable between a second insertion position that guides light from the imaging optical system to the imaging unit and a second retraction position that faces the imaging unit. In this control method, in the optical finder mode in which light from the imaging optical system is guided to the observation optical system, the mirror drive control unit drives the second mirror to the second retracted position and drives the first mirror to the first insertion position. In the optical finder switching step and the electronic finder mode in which the light from the imaging optical system is guided to the imaging unit, the first mirror is driven to the first retracted position by the mirror drive control unit, and the second mirror is in the second insertion position. And an electronic finder switching step driven until.

In this control method, the first and second mirrors are driven to the first insertion position and the second retracted position in the optical finder switching step. In the electronic finder switching step, the first and second mirrors are driven to the first retracted position and the second insertion position. Therefore, in the optical viewfinder mode, the photographer can confirm the subject using the observation optical system, and in the electronic viewfinder mode, the photographer can confirm the subject using the image display unit.
At this time, for example, when the first and second mirrors are semi-transmissive mirrors, a state where light from the imaging optical system is incident on the observation optical system and a state where light from the imaging optical system is incident on the imaging unit Thus, a part of the light from the imaging optical system can be incident on the focus detection unit. That is, in this control method, the optical finder mode and the electronic finder mode can be switched by switching the positions of the first and second mirrors, and the focus detection function can be realized in the optical finder mode and the electronic finder mode. .

Since the camera system and the camera body according to the present invention have the above-described configuration, the focus detection function can be realized in the optical finder mode and the electronic finder mode.
Since the camera system control method according to the present invention has the above-described configuration, the focus detection function can be realized in the optical finder mode and the electronic finder mode.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
<1: Overall configuration of camera system>
The camera system according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an external view of a camera system according to the first embodiment of the present invention.
As shown in FIG. 1, the camera system 1 is an interchangeable lens single-lens reflex digital camera system, and mainly includes a camera body 3 having the main functions of the camera system 1 and a detachable attachment to the camera body 3. The interchangeable lens 2 is made up of. The interchangeable lens 2 is attached to a lens mount 70 provided on the front surface of the camera body 3.
(1.1: Camera body)
The camera body 3 mainly includes an imaging unit 71 that images a subject, a body microcomputer 12 as a control unit that controls the operation of each unit such as the imaging unit 71, and an image display unit 72 that displays captured images and various types of information. And an image storage unit 73 for storing image data, a finder optical system 19 as an observation optical system for visually recognizing a subject image, and light from the imaging optical system L of the interchangeable lens 2 to the finder optical system 19 or the imaging unit 71. The optical path switching unit 74 guides and the focus detection unit 5 that detects the focus (the in-focus state of the imaging optical system L).

The imaging unit 71 mainly includes an imaging sensor 11 as an imaging element such as a CCD that performs photoelectric conversion, a shutter unit 10 that adjusts an exposure state of the imaging sensor 11, and a shutter unit 10 based on a control signal from the body microcomputer 12. The shutter control unit 14 controls the driving of the imaging sensor 11 and the imaging sensor control unit 13 controls the operation of the imaging sensor 11.
The body microcomputer 12 is a control device that controls the center of the camera body 3 and controls various sequences. Specifically, the body microcomputer 12 is equipped with a CPU, a ROM, and a RAM, and the body microcomputer 12 can realize various functions by reading a program stored in the ROM into the CPU. For example, the body microcomputer 12 has a function of detecting that the interchangeable lens 2 is attached to the camera body 3 and an electronic shutter function of the image sensor 11. As shown in FIG. 1, the body microcomputer 12 is connected to each part provided in the camera body 3.
The image display unit 72 includes a liquid crystal monitor 16 and an image display control unit 15 that controls the operation of the liquid crystal monitor 16. The image storage unit 73 includes, for example, an image recording / reproducing unit 18 that records and reproduces a captured image on a card-type recording medium (not shown), and an image recording control unit 17 that controls the operation of the image recording / reproducing unit 18. Has been.

The finder optical system 19 includes a finder screen 6 on which a subject image is formed, a pentaprism 7 that converts the subject image into an erect image, an eyepiece 8 that guides the erect image of the subject to the finder eyepiece window 9, and a photographer. A viewfinder eyepiece window 9 for observing the subject image.
As shown in FIGS. 1 and 2, the camera body 3 includes a release button 50 that allows the photographer to perform half-press and full-press operations during focus adjustment and release, and a finder changeover switch 51 that allows the photographer to switch the viewfinder. And are provided. Specifically, in this camera system 1, an OPVF (Optical View Finder) mode as an optical finder mode in which an object image (an optical image of an object) can be confirmed from the optical viewfinder eyepiece 3 and an object image is confirmed from the liquid crystal monitor 16. It is possible to switch to an EVF (Electro View Finder) mode as a possible electronic finder mode. The two view modes are realized by an optical path switching unit 74 described below.
Here, the optical path switching unit 74 will be described with reference to FIGS. FIG. 3 is a schematic vertical sectional view around the optical path switching unit in the OPVF mode, and FIG. 4 is a schematic vertical sectional view around the optical path switching unit in the EVF mode.
As shown in FIG. 2, the optical path switching unit 74 mainly includes a first mirror 60 that guides incident light to the finder optical system 19 and the focus detection unit 5 and a second mirror that guides incident light to the imaging unit 71 and the focus detection unit 5. The mirror 61, a first mirror driving unit 62 that rotationally drives the first mirror 60, and a second mirror driving unit 63 that rotationally drives the second mirror 61 are configured. The OPVF mode is realized by the first mirror 60, and the EVF mode is realized by the second mirror 61.

As shown in FIGS. 3 and 4, the first mirror 60 is on the X-axis direction negative side of the optical path A1 from the first mirror 60 to the finder optical system 19 (on the opposite side to the imaging optical system L across the optical path A1). It has the 1st rotating shaft 60a arrange | positioned and extended in a Y-axis direction. The first mirror 60 can rotate within a certain range (in the present embodiment, within a range of 45 degrees) around the first rotation shaft 60a. Specifically, the first mirror 60 can rotate between a first insertion position P1 that guides light from the imaging optical system L to the finder screen 6 and a first retraction position P2 that faces the finder screen 6.
As shown in FIG. 3, at the first insertion position P1, the first mirror 60 is open on the imaging optical system L side (X-axis direction positive side), and the first reflecting surface 60b of the first mirror 60 has an optical axis A. It is inclined 45 degrees with respect to. The first mirror 60 is a semi-transmissive mirror. For this reason, part of the light from the imaging optical system L is bent 90 degrees toward the viewfinder screen 6, and the remaining light is not reflected but passes through the first mirror 60 and enters the focus detection unit 5 described later. On the other hand, as shown in FIG. 4, at the first retracted position P <b> 2, the first reflecting surface 60 b of the first mirror 60 faces the incident surface 6 a of the finder screen 6, and the first reflecting surface of the first mirror 60. Light from the imaging optical system L does not enter 60b.

As shown in FIGS. 3 and 4, the second mirror 61 is disposed on the negative side in the X-axis direction of the optical path A2 from the second mirror 61 to the imaging sensor 11 (on the opposite side to the imaging optical system L across the optical path A2). And has a second rotation shaft 61a extending in the Y-axis direction. The second mirror 61 is disposed around the light receiving surface 11a of the image sensor 11 (more specifically, on the Z axis direction positive side of the shutter unit 10). The second mirror 61 can rotate within a certain range (in this embodiment, within a range of 45 degrees) around the second rotation shaft 61a. Specifically, the second mirror 61 is provided between the second insertion position P3 that guides light from the imaging optical system L to the imaging sensor 11 and the second retraction position P4 that faces the imaging sensor 11 with the shutter unit 10 interposed therebetween. It can be rotated.
As shown in FIG. 4, at the second insertion position P3, the second mirror 61 is open on the imaging optical system L side (X-axis direction positive side), and the second reflecting surface 60b of the second mirror 61 has an optical axis A. It is inclined 45 degrees with respect to. Similar to the first mirror 60, the second mirror 61 is a semi-transmissive mirror. For this reason, a part of the light from the imaging optical system L is bent 90 degrees toward the imaging sensor 11, and the remaining light passes through the second mirror 61 without being reflected and enters the focus detection unit 5 described later. Further, the intersection of the optical axis A and the first reflecting surface 60b at the first insertion position P1 substantially coincides with the intersection of the optical path A and the second reflecting surface 60b at the second insertion position P3. On the other hand, as shown in FIG. 3, at the second retracted position P4, the second reflecting surface 60b of the second mirror 61 faces the light receiving surface 11a of the image sensor 11 with the shutter unit 10 in between, and the second mirror The light from the imaging optical system L does not enter the second reflecting surface 60 b of 61.

Further, the first mirror 60 and the second mirror 61 are substantially equal in thickness. The tilt angle of the first mirror 60 with respect to the optical axis A at the first insertion position P1 is substantially equal to the tilt angle of the second mirror 61 with respect to the optical axis A at the second insertion position P3. As a result, the optical path lengths of the subject images that have passed through the first mirror 60 and the second mirror 61 become equal, and the common focus detection unit 5 can focus. For this reason, it is possible to obtain the same focus detection accuracy in the OPVF mode and the EVF mode. In this embodiment, the inclination angle is 45 degrees, but is not limited to this.
The first mirror driving unit 62 and the second mirror driving unit 63 are actuators such as stepping motors, for example, and their operations are controlled by the body microcomputer 12. The first mirror 60 is rotationally driven in the Z-axis direction around the first rotation axis 60a by the first mirror driving unit 62, and the second mirror 61 is centered around the second rotation axis 61a by the second mirror driving unit 63. It is rotationally driven in the direction. The first mirror drive unit 62, the second mirror drive unit 63, and the body microcomputer 12 constitute a mirror drive control unit that controls the drive of the first mirror 60 and the second mirror 61.
With the above configuration, the driving of the first mirror 60 and the second mirror 61 is controlled so that the light from the imaging optical system L is incident on only one of the first mirror 60 and the second mirror 61. When the first mirror 60 is at the first insertion position P1 and the second mirror 61 is at the second retracted position P4, the photographer can confirm the subject image with the optical viewfinder eyepiece 3, and the first mirror 60 is in the first position. When the retracted position P2 and the second mirror 61 are at the second insertion position P3, the photographer can check the subject image on the liquid crystal monitor 16. In the OPVF and EVF modes, light from the imaging optical system L passes through the first mirror 60 or the second mirror 61 and enters the focus detection unit 5.

The focus detection unit 5 is a module for performing focus detection by the phase difference detection method using light from the imaging optical system L, and is disposed outside the movable range of the first mirror 60 and the second mirror 61. . Specifically, the focus detection unit 5 is disposed on the optical axis A and between the finder screen 6 and the image sensor 11 in the Z-axis direction. More specifically, the focus detection unit 5 is disposed between the first rotation shaft 60a and the second rotation shaft 61a in the Z-axis direction. As shown in FIGS. 3 and 4, the focus detection unit 5 mainly forms a pair of optical images with a condenser lens 57 that converts the light transmitted through the first mirror 60 or the second mirror 61 into substantially parallel light. And a CCD line sensor 55 as a detection element that performs photoelectric conversion on a pair of optical images formed by the separator lens 56. In the present embodiment, a phase difference calculation unit (not shown) that determines in-focus based on a pair of images acquired by the CCD line sensor 55 is realized in, for example, the body microcomputer 12. The condenser lens 57 is a single concave lens.
For example, a pair of images obtained by the CCD line sensor 55 are compared by the phase difference calculation unit, and it is determined at which position of each image a specific pattern exists. Then, the distance between the same patterns is measured by the phase difference calculation unit, and the phase difference is obtained from this measured distance and a predetermined set distance. For example, when the measurement distance is narrower than the set distance, it is determined that the focus is in front of the subject, and when the measurement distance is wider than the set distance, the focus is determined to be behind the subject. Further, when the measurement distance and the set distance are the same, or when the difference between the measurement distance and the set distance is equal to or less than a preset reference value, it is determined to be in focus. Based on these determination results, the focus lens group 24 is driven by the focus lens group control unit 25 to perform focus adjustment.

With the above configuration, the light from the imaging optical system L enters the focus detection unit 5 regardless of the positions of the first mirror 60 and the second mirror 61. That is, the camera system 1 can always detect the focus in the OPVF mode and the EVF mode.
(1.2: Interchangeable lens)
The interchangeable lens 2 constitutes an imaging optical system L for connecting a subject image to the imaging sensor 11 in the camera system 1, and mainly includes a focus adjustment unit 80 that performs focus adjustment and an aperture adjustment unit that adjusts the aperture. 81, a lens image blur correction device 82 that corrects image blur by adjusting the optical path, and a lens microcomputer 20 as a lens control unit that controls the operation of the interchangeable lens 2.
The focus adjustment unit 80 mainly includes a focus lens group 24 that adjusts the focus, and a focus lens group control unit 25 that controls the operation of the focus lens group 24. In accordance with the phase difference detected by the focus detection unit 5 and the body microcomputer 12, the focus lens group control unit 25 drives the focus lens group 24 to perform focus adjustment. The aperture adjustment unit 81 mainly includes an aperture unit 26 that adjusts the aperture, and an aperture control unit 27 that controls the operation of the aperture unit 26. The aperture adjustment unit 81 opens the aperture appropriately when using the optical viewfinder and appropriately reduces the aperture according to the subject brightness when using the electronic viewfinder, according to a command from the camera body 3. The aperture adjustment unit 81 adjusts the aperture based on information set automatically or manually so that the shutter speed and the aperture amount satisfy a predetermined relationship at the time of shooting.

The lens image blur correction device 82 is an optical image blur correction device. The lens image blur correction device 82 mainly detects the blur of the camera system 1 and the amount of blur detected by the blur detection unit 21. The lens image blur correction unit 83 corrects image blur. The shake detection unit 21 incorporates an angular velocity sensor such as a gyro sensor. The image blur correction unit 83 mainly includes a blur correction lens group 22 constituting a part of the imaging optical system L, and a correction lens that moves the blur correction lens group 22 in a plane orthogonal to the optical axis A of the imaging optical system L. The driving unit 28 includes an image blur correction control unit 23 that controls the operation of the correction lens driving unit 28 according to the blur amount detected by the blur detection unit 21.
The lens microcomputer 20 is a control device that controls the center of the interchangeable lens 2, and is connected to each unit mounted on the interchangeable lens 2. Specifically, the lens microcomputer 20 is equipped with a CPU, a ROM, and a RAM, and various functions can be realized by reading a program stored in the ROM into the CPU. For example, the lens microcomputer 20 has a function of controlling operations of the focus adjustment unit 80, the aperture adjustment unit 81, and the lens image blur correction device 82 based on a signal from the body microcomputer 12. In addition, the body microcomputer 12 and the lens microcomputer 20 are electrically connected via an electrical section (not shown) provided in the lens mount 70, so that information can be transmitted and received between them.

<2: Operation of the camera system>
The shooting operation of the camera system 1 will be described with reference to FIGS.
(2.1: State before shooting)
When the power switch (not shown) of the camera body 3 is OFF, the finder mode is the OPVF mode as shown in FIG. For this reason, in the power OFF state, the first mirror 60 is disposed at the first insertion position P1, and the second mirror 61 is disposed at the second retraction position P4. The second mirror 61 can suppress dust and the like from adhering to the image sensor 11. In this state, as shown in FIG. 3, light from a subject (not shown) passes through the imaging optical system L and enters the first mirror 60 that is a semi-transmissive mirror. A part of the light incident on the first mirror 60 is reflected by the first reflecting surface 60 b and incident on the finder screen 6, and the remaining light is transmitted through the first reflecting surface 60 b and incident on the focus detection unit 5. The subject image incident on the finder screen 6 is converted into an erect image by the pentaprism 7 and enters the eyepiece 8. Thus, the photographer can observe an erect image of the subject through the viewfinder eyepiece window 9.
(2.2: Operation during shooting)
Here, the operation at the time of photographing will be described with reference to FIGS. 5 and 6 show an operation flow of the camera system 1.

As shown in FIG. 5, when the power switch of the camera system 1 is turned on, power is supplied to each part, and the state of the finder selector switch 51 is confirmed by the body microcomputer 12 (S1). When the finder switch 51 is in the OPVF mode, it is not necessary to change the state of the optical path switching unit 74. Therefore, in the OPVF mode, the camera system 1 is in a standby state until the photographer operates the release button 50 (S2).
On the other hand, when the finder selector switch 51 is in the EVF mode, the first mirror 60 is rotationally driven to the first retracted position P2 by the first mirror driving unit 62, and the second mirror 61 is moved to the second insertion position by the second mirror driving unit 63. It is rotationally driven up to P3 (S1, S11). Further, the shutter control unit 14 opens the shutter unit 10 (S11). For this reason, the light from the imaging optical system L is reflected by the second reflecting surface 60 b of the second mirror 61 and enters the imaging sensor 11. As a result, an image of the subject is displayed on the liquid crystal monitor 16. That is, live view in the EVF mode is started (S12). As a result, the photographer can confirm the subject image via the liquid crystal monitor 16. Then, as in the OPVF mode, the camera system 1 is in a standby state until the photographer presses the release button 50 halfway (S13).

When the photographer presses the release button 50 halfway, an exposure preparation operation is started. Specifically, in order to perform focus adjustment, the focus detector 5 detects the phase difference between the pair of optical images (S3, S14). If the phase difference is zero or less than the reference value, it is determined that the subject is in focus, and if not in focus, the focus lens group controller 25 drives the focus lens group 24 according to the phase difference (S4, S5). If it is determined that the subject is in focus, the camera system 1 is in a standby state until the photographer fully presses the release button 50. Along with focus adjustment, for example, aperture adjustment is performed by the aperture adjustment unit 81, but the description thereof is omitted here.
As shown in FIG. 5, in the OPVF mode, when the photographer fully presses the release button 50, the optical path is switched by the optical path switching unit 74 in order to capture an optical image of the subject (S6, S7). Specifically, the first mirror driving unit 62 rotationally drives the first mirror 60 to the first retracted position P2, and the second mirror driving unit 63 rotationally drives the second mirror 61 to the second insertion position P3 ( S7). As a result, the light from the imaging optical system L is reflected by the second mirror 61 toward the imaging sensor 11 side. After the switching of the optical path in the optical path switching unit 74 is completed, the shutter unit 10 exposes the image sensor 11 for a predetermined time (S8). After the exposure is completed, the second mirror 61 is rotated by the second mirror controller 63 to the second retracted position P4, and the first mirror 60 is rotated by the first mirror driver 62 to the first insertion position P1. (S9).

On the other hand, as shown in FIG. 6, in the EVF mode, the light from the imaging optical system L has already entered the imaging sensor 11. Therefore, it is not necessary to switch the optical path by the optical path switching unit 74, and when the photographer fully presses the release button 50, the exposure operation is started (S17, S18). For this reason, compared with the OPVF mode, in the EVF mode, the time (release time lag) from when the release button 50 is fully pressed to when the exposure operation is started can be shortened, and quick shooting without a sense of incongruity becomes possible.
Since the shutter unit 10 is in the open state in the EVF mode, for example, the electronic sensor function realized by the image sensor control unit 13 and the body microcomputer 12 is used to take in charges by the image sensor 11 for the set exposure time. Is called.
<3: Effect>
The effects of the camera system 1 according to the present invention are summarized below.
In the camera system 1, for example, when the photographer confirms the optical image of the subject in the finder optical system 19 (in the OPVF mode), the optical image is guided to the finder optical system 19 by the first mirror 60, and the liquid crystal monitor When the photographer confirms the optical image of the subject using 16 (in the case of EVF mode), the optical image is guided to the image sensor 11 by the second mirror 61. At this time, since the first and second mirrors are semi-transmissive mirrors, the light from the imaging optical system L is incident on the finder optical system 19 and the imaging sensor 11 of the imaging unit 71 from the imaging optical system L. A part of the light from the imaging optical system L can be incident on the focus detection unit 5 in a state where the light is incident. That is, in the camera system 1, the focus detection function can be realized in the OPVF mode and the EVF mode.

Further, in this camera system 1, since the first mirror 60 and the second mirror 61 are mounted, it is possible to switch between the OPVF mode and the EVF mode while realizing the focus detection function.
In the EVF mode, it is not necessary to switch the first mirror 60 and the second mirror 61 between the start of exposure preparation such as focus adjustment and the start of exposure. For this reason, in the EVF mode, the release time lag can be shortened, and quick shooting without a sense of incongruity becomes possible.
Furthermore, since the focus detection unit 5 is located outside the movable range of the first mirror 60 and the second mirror 61 and is disposed between the finder screen 6 and the image sensor 11, the camera system 1 can be reduced in size. .
<Other embodiments>
The specific configuration of the present invention is not limited to the above-described embodiment, and various changes and modifications can be made without departing from the scope of the invention.
(1)
In the above-described embodiment, a single-lens reflex digital camera has been described as an example, but the present invention is not limited to this. For example, the present invention can also be applied to other photographing systems such as a digital still camera and a digital video camera that can switch between the optical finder mode and the electronic finder mode.

(2)
In the above-described embodiment, the first mirror 60 and the second mirror 61 are semi-transmissive mirrors, but the second mirror 61 may be a total reflection mirror. In this case, in the EVF mode, light from the imaging optical system L does not enter the focus detection unit 5. However, the focus adjustment can be performed by performing focus detection by the contrast detection method using the imaging sensor 11. In this case, the present invention is not limited to still image shooting. For example, conventional video AF can be used when shooting a moving image using live view, and very smooth focus adjustment is possible.
In this case, for example, the imaging unit 71 and the body microcomputer 12 constitute a contrast detection type focus detection unit as the second focus detection unit.

  The photographing system, camera system, camera body, and photographing system control method according to the present invention are suitable for photographing systems such as single-lens reflex digital cameras and digital video cameras that require switching between the optical finder mode and the electronic finder mode. It is.

1 is an external view of a camera system according to a first embodiment of the present invention. 1 is a schematic configuration diagram of a camera system according to a first embodiment of the present invention. Schematic of longitudinal section around optical path switching unit in OPVF mode Schematic of longitudinal section around optical path switching unit in EVF mode Operation flow diagram of camera system Operation flow diagram of camera system

Explanation of symbols

L Imaging optical system A Optical path A1 Optical path (optical path from the first mirror to the observation optical system)
A2 optical path (optical path from the second mirror to the imaging unit)
1 Camera system (shooting system)
2 Interchangeable Lens 3 Camera Body 5 Focus Detection Unit 6 Viewfinder Screen 6a Incident Surface 10 Shutter Unit 11 Image Sensor (Image Sensor)
11a Light-receiving surface 12 Body microcomputer 19 Finder optical system (observation optical system)
20 Lens microcomputer 51 Finder selector switch 55 CCD line sensor (detection element)
56 Separator lens 57 Condenser lens 60 First mirror 60a First rotating shaft 60b First reflecting surface 61 Second mirror 61a Second rotating shaft 60b Second reflecting surface 62 First mirror driving unit 63 Second mirror driving unit 71 Imaging unit 72 Image display unit P1 first insertion position P2 first retraction position P3 second insertion position P4 second retraction position

Claims (14)

A photographing system for photographing a subject,
An imaging optical system for capturing light from the subject;
An imaging unit that acquires an image of the subject by performing photoelectric conversion on light from the imaging optical system;
An observation optical system for confirming light from the imaging optical system from the outside;
An image display unit for displaying an image of the subject acquired by the imaging unit;
A first mirror for guiding light from the imaging optical system to the observation optical system;
A second mirror for guiding light from the imaging optical system to the imaging unit;
A focus detection unit for detecting the in-focus state of the imaging optical system;
Shooting system equipped with. The first mirror is movable between a first insertion position for guiding light from the imaging optical system to the observation optical system and a first retraction position facing the observation optical system;
The second mirror is movable between a second insertion position for guiding light from the imaging optical system to the imaging unit and a second retraction position facing the imaging unit.
The imaging system according to claim 1. The observation optical system has an incident optical axis perpendicular to the optical axis of the imaging optical system and an incident surface on which light from the imaging optical system is incident;
The image pickup unit includes an image pickup device that performs photoelectric conversion on light from the image pickup optical system and includes a light receiving surface disposed to face the incident surface across the optical axis of the image pickup optical system. And
The first mirror has a first reflecting surface facing the incident surface at the first retracted position;
The second mirror has a second reflecting surface facing the light receiving surface at the second retracted position.
The imaging system according to claim 2. The first mirror has a first rotation axis disposed on the opposite side of the imaging optical system across an optical path from the first mirror to the observation optical system,
The second mirror has a second rotation axis that is disposed on the opposite side of the imaging optical system across an optical path from the second mirror to the imaging unit.
The imaging system according to any one of claims 1 to 3. The first mirror is a transflective mirror;
The focus detection unit is disposed outside the movable range of the first and second mirrors and at a position where light from the imaging optical system that passes through the first mirror enters.
The imaging system according to any one of claims 1 to 4. The focus detection unit includes a detection element, a separator lens that divides a subject image from the imaging optical system and forms an image on the detection element, and a concave capacitor that guides light from the imaging optical system to the separator lens A lens,
The imaging system according to any one of claims 1 to 5. The second mirror is a transflective mirror;
The imaging system according to claim 5. The first mirror and the second mirror have substantially the same thickness, and the inclination angles with respect to the incident optical axis at the first and second insertion positions are substantially equal.
The imaging system according to claim 7. The second mirror is a total reflection mirror;
A second focus detection unit that detects the in-focus state of the imaging optical system using the imaging unit;
The imaging system according to claim 5. A mirror drive controller for controlling the driving of the first and second mirrors;
The mirror drive control unit drives the first and second mirrors so that light from the imaging optical system is incident on only one of the first and second mirrors;
The imaging system according to any one of claims 1 to 9. A mirror drive controller for controlling the driving of the first and second mirrors;
In an optical finder mode in which light from the imaging optical system is guided to the observation optical system, the mirror drive control unit drives the second mirror to the second retracted position and inserts the first mirror into the first insertion Drive to position,
In an electronic finder mode in which light from the imaging optical system is guided to the imaging unit, the mirror drive control unit drives the first mirror to the first retracted position, and the second mirror moves to the second insertion position. Drive up to,
The imaging system according to claim 2. A camera system for photographing a subject,
An interchangeable lens having an imaging optical system that captures light of the subject;
An imaging unit that acquires an image of the subject by performing photoelectric conversion on the light from the imaging optical system, an observation optical system for confirming light from the imaging optical system from the outside, and the imaging unit An image display unit that displays the acquired image of the subject, a first mirror that guides light from the imaging optical system to the observation optical system, and a second mirror that guides light from the imaging optical system to the imaging unit And a focus detection unit that detects the in-focus state of the imaging optical system, and a camera body to which the interchangeable lens is detachable,
Camera system equipped with. A camera body for photographing a subject is used together with an interchangeable lens having an imaging optical system that takes light from the subject, and the interchangeable lens is a detachable camera body,
An imaging unit that acquires an image of the subject by performing photoelectric conversion on light from the imaging optical system;
An observation optical system for confirming light from the imaging optical system from the outside;
An image display unit for displaying an image of the subject acquired by the imaging unit;
A first mirror for guiding light from the imaging optical system to the observation optical system;
A second mirror for guiding light from the imaging optical system to the imaging unit;
A focus detection unit for detecting the in-focus state of the imaging optical system;
Camera body equipped with. An imaging optical system that captures light from a subject, an observation optical system for confirming light from the imaging optical system from the outside, an image display unit that displays an image of the subject acquired by the imaging unit, and A first mirror that guides light from the imaging optical system to the observation optical system, a second mirror that guides light from the imaging optical system to the imaging unit, and a focus detection unit that detects the in-focus state of the imaging optical system And a mirror drive control unit for controlling the drive of the first and second mirrors,
The first mirror is movable between a first insertion position for guiding light from the imaging optical system to the observation optical system and a first retraction position facing the observation optical system;
The second mirror is movable between a second insertion position for guiding light from the imaging optical system to the imaging unit and a second retracted position facing the imaging unit,
In an optical finder mode in which light from the imaging optical system is guided to the observation optical system, the mirror driving control unit drives the second mirror to the second retracted position, and the first mirror is in the first insertion position. An optical finder switching process driven to
In the electronic finder mode in which light from the imaging optical system is guided to the imaging unit, the mirror driving control unit drives the first mirror to the first retracted position, and the second mirror to the second insertion position. A driven electronic finder switching step;
A method for controlling an imaging system including:

Images