JP2011007985A - Digital camera body and digital camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a digital camera body and a digital camera which can for image an object by video while reducing noise during imaging.SOLUTION: The digital camera body 10 includes an imaging part 15 which can image an object formed by an optical member 31 by video, a driving member 17 for moving the imaging part 15 along an optical axis of the optical member 31 to let an image of the object be focused on the imaging part 15, and a control means 40 for moving the imaging part 15 for the optical member 31 held at the predetermined position by the driving member 17 for focusing.

Description

  The present invention relates to a digital camera body having a moving image shooting function and a digital camera.

  Conventionally, in an AF operation of a digital camera, a photographing lens is moved and focused based on distance measurement information by an AF module.

  Further, a focusing method for performing an AF operation by moving the image sensor along the optical axis has been proposed (for example, see Patent Document 1).

Japanese Patent Publication No. 5-23102

  However, if the AF operation is performed by moving the taking lens during moving image shooting, the lens driving sound is also recorded. Therefore, it is necessary to make the lens driving mechanism a silent structure as a noise prevention measure. However, in the case of an interchangeable lens already owned by the user, it is difficult to reduce the noise because the drive mechanism is incorporated in the lens.

  Further, when the AF operation is performed by moving the image sensor as in Patent Document 1, the lens position is indeterminate, and the amount of movement of the image sensor necessary for contrast detection becomes large.

  An object of the present invention is to provide a digital camera body and a digital camera that can perform moving image shooting with less noise during moving image shooting.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
According to the first aspect of the present invention, an imaging unit (15) capable of capturing a moving subject image formed by the optical member (31) and the optical unit for focusing the subject image on the imaging unit (15). The drive member (17) moves the imaging unit (15) along the optical axis of the member (31) and the optical member (31) held at a predetermined position by the drive member (17). A digital camera body comprising a control means (40) for moving and focusing the image pickup section (15).
According to a second aspect of the present invention, there is provided the digital camera body according to the first aspect, further comprising a microphone (26) for recording during moving image shooting.
A third aspect of the present invention is the digital camera main body according to the first or second aspect, wherein the imaging unit (15) can switch and execute still image shooting or moving image shooting. It is a digital camera body.
Invention of Claim 4 is a digital camera main body of any one of Claims 1-3, Comprising: The said control means (40) is the said optical member (Holded at an infinite focus position). 31) The digital camera, wherein the image pickup unit (15) is moved with the image plane position on which the subject image is formed as the front end when the optical member (31) is at the infinite focus position. It is the main body.
The invention according to claim 5 is an optical member (31), an imaging unit (15) capable of taking a moving image of a subject image formed by the optical member (31), and the subject image of the imaging unit (15). To the driving member (17) for moving the imaging unit (15) along the optical axis of the optical member (31) and the optical member (31) held at a predetermined position. It is a digital camera provided with the control means (40) which moves and focuses the said imaging part (15) with the said drive member (17).
A sixth aspect of the present invention is the digital camera according to the fifth aspect, further comprising a microphone (26) for recording during moving image shooting.
A seventh aspect of the present invention is the digital camera according to the fifth or sixth aspect, wherein the imaging unit (15) can execute switching between still image shooting and moving image shooting. It is a camera.
Invention of Claim 8 is a digital camera of any one of Claims 5-7, Comprising: The said control means (40) is hold | maintained at the infinity in-focus position at the time of video recording. The imaging unit (15) is moved relative to the optical member (31) with the image plane position where the subject image is formed as the front end when the optical member (31) is at an infinite focus position. It is a digital camera.
A ninth aspect of the present invention is the digital camera according to the seventh aspect, wherein the control means (40) is arranged for the imaging unit (15) held at a predetermined position during still image shooting. The digital camera is characterized in that the optical member (31) is moved and focused.
A tenth aspect of the present invention is the digital camera according to the ninth aspect, wherein the control means (40) is arranged such that the optical member (15) is located with respect to the imaging unit (15) held at an image plane position. 31) is a digital camera characterized in that when the imaging unit (15) is at the image plane position, the infinite focus position where an infinite subject image is formed is moved as a rear end.
The invention according to claim 11 is the digital camera according to claim 7, wherein the control means (40) is adapted to prevent the optical member (31) held at the infinite focus position during moving image shooting. The drive member (17) causes the image pickup unit (15) to focus by moving the image plane position where the subject image is formed when the optical member (31) is at the infinite focus position as the front end. In addition, at the time of still image shooting, the optical member (31) is placed at an infinite distance with respect to the imaging unit (15) held at the image plane position when the imaging unit (15) is at the image plane position. The digital camera is characterized in that the infinite focus position where the subject image is formed is moved as a rear end to be focused.

  ADVANTAGE OF THE INVENTION According to this invention, the digital camera main body and digital camera which can perform video recording with few noises at the time of video recording can be provided.

It is a schematic block diagram at the time of still image photography which shows 1st Embodiment of the digital camera by this invention. It is a schematic block diagram at the time of the video recording which shows 1st Embodiment of the digital camera by this invention. It is explanatory drawing which shows the positional relationship of the imaging lens and image pick-up element at the time of still image photography. It is explanatory drawing which shows the positional relationship of the imaging lens and imaging device at the time of video recording. It is a schematic block diagram which shows the circuit structure of this embodiment. It is a flowchart which shows operation | movement of this embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. Each figure shown below is provided with an xyz orthogonal coordinate system for easy explanation and understanding. In this coordinate system, the direction toward the left as viewed from the photographer at the position of the camera when the photographer shoots a horizontally long image with the optical axis A horizontal (hereinafter referred to as a normal photographing position) is the x plus direction. . Also, the direction toward the upper side at the normal photographing position is the y plus direction. Furthermore, the direction toward the subject at the normal shooting position is the z plus direction.

  1 and 2 are schematic configuration diagrams showing a first embodiment of a digital camera according to the present invention. FIG. 1 shows a state during still image shooting, and FIG. 2 shows a state during moving image shooting.

  The digital camera 1 is a digital single-lens reflex camera, and includes a camera body (camera body) 10 and a lens barrel 30 that is detachably attached to the camera body 10.

  The camera body 10 includes a mirror unit 11, a shutter 14, an imaging unit 15, a monitor 19, a finder unit 20, an AF module 24, an AF motor 25, and a microphone 26.

  The mirror unit 11 includes a first mirror 12 and a second mirror 13, and is switched between a mirror-down state shown in FIG. 1 and a mirror-up state shown in FIG. When in the mirror-down state, the first mirror 12 is a reflection mirror that reflects subject light emitted from the rear part of the photographing lens 31 described later to the finder unit 20. The second mirror 13 is a reflecting mirror that reflects the subject light transmitted through the semi-transmissive mirror provided on a part of the reflecting surface of the first mirror 12 to the AF module 24.

  The shutter 14 includes a plurality of shutter blade groups (not shown). The shutter blade groups are synchronized with the mirror unit 11 being flipped up to the mirror-up state shown in FIG. Is opened and closed, and subject light enters the imaging unit 15.

  The imaging unit 15 includes an imaging element 16, an actuator 17, and an imaging element regulating member 18. The imaging device 16 is a solid-state imaging device such as a CCD or CMOS, converts incident subject light into an electrical image signal, and outputs the electrical image signal to image processing units 42, 43, and 44 described later. The actuator 17 is a drive member such as an ultrasonic motor, for example, and supports the image sensor 16 to move along the optical axis A direction (z direction). The imaging element regulating member 18 regulates the moving direction front end (z direction front end) of the imaging element 16 moved by the actuator 17.

  The monitor (image display unit) 19 is a liquid crystal display that is provided at the rear of the camera body 10 and displays a subject image photographed by the imaging unit 15, information related to operation, and the like.

  The finder unit 20 includes a finder screen 21, a pentaprism 22, and an eyepiece 23. The viewfinder screen 21 is a screen for forming an image by entering subject light reflected from the first mirror 12 when the mirror unit 11 is in the mirror-down state. The pentaprism 22 is a polygonal prism that emits subject light imaged by the finder screen 21 to the eyepiece 23. The eyepiece 23 is an eyepiece optical system arranged at a position where the subject light emitted from the pentaprism 42 is incident.

  When the mirror unit 11 is in the mirror-down state, the AF module 24 receives subject light reflected from the second mirror 13 and performs arithmetic processing for focusing the subject and the digital camera 1. In response to this, a drive signal for the AF motor 25 is output.

  On the other hand, the lens barrel 30 includes a photographic lens (optical member) 31 and a focusing lens driving mechanism 34. The taking lens 31 includes a fixed lens 32 and a focusing lens 33. The fixed lens 32 is a lens group fixed to the frame of the lens barrel 30, and the focusing lens 33 is a lens group attached to the frame of the lens barrel 30 so as to be movable along the optical axis A direction. It is.

  The focusing lens driving mechanism 34 is drivingly connected to the AF motor 25 when the lens barrel 30 is attached to the camera body 10. Then, when the AF motor 25 is driven based on the output signal of the AF module 24, the focusing lens driving mechanism 34 moves the focusing lens 33 along the optical axis A direction (z direction).

  FIG. 3 shows the positional relationship between the photographing lens 31 and the image sensor 16 during still image photographing.

  As for the position of the image pickup device 16, FIGS. 3A and 3B are image plane positions (the position of the image pickup device in a normal digital camera), and FIGS. 3C and 3D are the rear positions. 3A, 3C, and 3D are infinite focus positions (positions that are focused when the subject position is infinite), and FIG. It is a more forward position.

  FIGS. 3A and 3B show the positional relationship between the photographing lens and the image sensor when the subject position is infinity and short distance in a normal digital camera. The positional relationship between the photographic lens 31 and the image sensor 16 is set as shown in FIGS.

  That is, as shown in FIG. 3A, when the imaging element 16 is at a predetermined position (image plane position) and the subject position is infinite, focusing can be performed by moving the photographic lens 31. As shown in FIG. 3B, when the image sensor 16 is at a predetermined position (image plane position) and the subject position is a short distance, the photographing lens 31 can be focused.

  On the other hand, as shown in FIG. 3C, when the imaging element 16 is different from the predetermined image plane position and the subject position is infinite, it is impossible to focus even if the photographing lens 31 is moved to the infinite position. is there. In addition, as shown in FIG. 3D, when the imaging element 16 is different from a predetermined image plane position and the subject position is a short distance, focusing can be performed by moving the photographing lens 31.

  In general, since the photographic lens and the image sensor are designed to have a predetermined mutual position, for example, as shown in FIG. 3C, the image sensor is arranged at a position different from the predetermined image plane position. In this case, the photographic lens designed for focusing may be out of the design movement range, and the photographic lens may not be able to focus when the photographic lens is moved. That is, in order to focus on the image sensor 16 by moving the photographic lens 31 according to the design range, the image sensor 16 needs to be held at a predetermined position (image plane position).

  FIG. 4 shows the positional relationship between the photographing lens 31 and the image sensor 16 during moving image photographing.

  As for the position of the image pickup device 16, FIG. 4A shows the image plane position (position of the image pickup device in a normal digital camera), FIG. 4B shows the rear position, and FIG. 4C shows the front of the image plane position. Position. 4 (a) and 4 (b) are infinite focus positions (positions where the subject is in focus when the subject position is infinite), and FIG. 4 (c) is the front position. is there.

  In this embodiment, at the time of moving image shooting, the positional relationship between the shooting lens 31 and the image sensor 16 is set as shown in FIGS.

  That is, as shown in FIG. 4A, when the photographing lens 31 is at a predetermined position (infinite focus position) and the subject position is infinite, the image sensor 16 is positioned at a predetermined image plane position. Can be burnt. Further, as shown in FIG. 4B, when the photographing lens 31 is at a predetermined position (focus position at infinity) and the subject position is a short distance, the image sensor 16 is at the image plane position (imaging in a normal digital camera). Focusing is possible by moving backward from the element position.

  On the other hand, as shown in FIG. 4C, when the position of the photographing lens 31 is indeterminate, focusing can be achieved by moving the image sensor 16 forward from the image plane position when the subject position is infinite. However, the movement range of the image sensor 16 is expanded.

  As described above, when the position of the photographing lens is indeterminate, it is necessary to move the image sensor over a wide range in order to perform contrast AF. As a result, the time until focusing is increased. In addition, the camera size is increased in order to secure a space for moving the image pickup device over a wide range.

  As shown in FIG. 5, the camera body 10 includes control means (camera control unit) 40 that controls the operation of the entire digital camera 1, and the camera control unit 40 includes a CPU. An image sensor driving circuit 41 and an ASIC (image processing circuit) 44 are connected to the camera control unit (camera CPU) 40.

  The image sensor drive circuit 41 drives the image sensor 16 with a signal from the camera CPU 40, and thereby the image sensor 16 outputs a photoelectric conversion signal based on the photographed image. An AFE (Analog Front End) circuit 42 to which the output signal of the image sensor 16 is input performs analog processing on the output signal of the image sensor 16. The A / D converter 43 to which the output signal of the AFE circuit 42 is input converts the photographing analog signal into a digital signal. The ASIC 44 to which the output signal of the A / D converter 43 is input performs predetermined image processing on the input signal.

  The camera CPU 40 is connected to an image display circuit 45, a moving image mode switch 46, an AF switch 47, and a release / moving image switch 48.

  The photographed / live view image processed by the ASIC 44 is displayed on the monitor 19 such as an LCD via the image display circuit 45. The moving image mode switch 46 is a switch for switching between still image / moving image shooting. When the AF switch 47 is turned on, the AF module 24 performs photometry and distance measurement. The release / moving image switch 48 is a switch for taking a still image when turned on. When the movie mode is set, movie shooting starts.

  Further, an AF circuit 51, an AF lens driving circuit 52, a mirror driving circuit 53, a shutter driving circuit 54, and an actuator driving circuit 55 are connected to the camera CPU 40.

  The AF circuit 51 performs phase difference AF based on a signal from the AF module 24. The AF lens driving circuit 52 moves the focusing lens (AF lens) 33 to the in-focus position based on information based on the phase difference AF. In the moving image mode, the focusing lens 33 is moved to a predetermined position. The mirror drive circuit 53 switches the first mirror 12 and the second mirror 13 to the mirror-down state shown in FIG. 1 or the mirror-up state shown in FIG. The shutter drive circuit 54 controls opening and closing of the shutter 14. The actuator drive circuit 55 controls the actuator 17 that moves the image sensor 16.

  FIG. 6 is a flowchart showing the operation of the camera CPU 40. First, the moving image shooting mode will be described.

  In step S101, it is determined whether or not the moving image shooting mode switch 46 is turned on.

  When the moving image shooting mode switch 46 is turned on (YES in step S101), in step S102, the focusing lens 33 moves to a predetermined position, that is, an infinite focus position. That is, when the AF motor 25 rotates, the focusing lens driving mechanism 34 moves the focusing lens 33 to the infinitely focused position. FIG. 2 shows a state where the focusing lens 33 is in the infinite focus position.

  In step S103, the first mirror 12 and the second mirror 13 are retracted from the photographing optical system. FIG. 2 shows a state (mirror up state) in which the mirror unit 11 (first mirror 12 and second mirror 13) is in a position retracted from the photographing optical system.

  In step S104, the shutter 14 is opened and the image sensor 16 is exposed. This state (state where the shutter 14 is opened and the image sensor 16 is exposed) continues until the shutter 14 is closed in step S110 described later.

  In step S105, it is determined whether or not the AF switch 47 is turned on to wait until the AF switch 47 is turned on.

  When the AF switch 47 is turned on (YES in step S105), in step S106, the image sensor 16 is moved and focused by contrast AF. In other words, the actuator 17 is driven, and the image sensor 16 is moved so that the subject image that has passed through the photographing lens 31 in which the focusing lens 33 is at the infinite focus position is focused on the image sensor 16. By using, for example, an ultrasonic motor as the actuator 17, it is possible to shoot a moving image with reduced AF driving sound (driving sound for moving the image sensor 16).

  In step S107, it is determined whether or not the moving image switch 48 is turned on. If the moving image switch 48 is not turned on (NO in step S107), the process returns to step S105 to wait for the AF switch 47 to be turned on again.

  When the moving image switch 48 is turned on (YES in step S107), moving image shooting is started in step S108. That is, a moving image is taken by the image pickup device 16 and recorded by the microphone 26.

  In step S109, it is determined whether or not the moving image switch 48 is turned off. If the moving image switch 48 is not turned off (NO in step S109), moving image shooting is continued until the moving image switch 48 is turned off.

  When the moving image switch 48 is turned off (YES in step S109), the shutter 14 is closed in step S110, and moving image shooting is ended. That is, the video recording by the image sensor 16 is finished and the recording by the microphone 26 is also finished.

  In step S111, the first mirror 12 and the second mirror 13 are restored. FIG. 1 shows a state (mirror down state) where the mirror unit 11 (first mirror 12 and second mirror 13) is in a position where it has returned to the photographing optical system.

  Next, the still image shooting mode will be described.

  If the moving image shooting mode switch 46 is turned off in step S101 (NO in step S101), the image sensor 16 is moved to a predetermined position (image plane position of the normal camera) in step S201. That is, by driving the actuator 17, the image sensor 16 is moved to a predetermined image plane position (position of the image sensor in a normal digital camera). The image sensor 16 cannot be moved any further by the image sensor restricting member 18, and is thereby held at the image plane position.

  In step S202, it is determined whether or not the AF switch 47 is turned on to wait until the AF switch 47 is turned on.

  When the AF switch 47 is turned on (YES in step S202), focusing is performed by phase difference AF in step S203. That is, the photographing light beam from the photographing lens 31 is divided into an optical finder light beam reflected by the first mirror 12 that is a half mirror and a focus detection light beam that is transmitted through the first mirror 12 and reflected by the second mirror 13. The

  The optical finder light flux sequentially passes through the finder screen 21, the pentaprism 22, and the eyepiece 23 of the finder unit 20. As a result, the photographer can visually confirm the subject.

  On the other hand, the focus detection light beam is guided to the AF module 24, and a distance measurement value based on the phase difference AF is calculated. The AF motor 25 rotates based on the distance measurement value, and the focusing lens drive mechanism 34 moves the focusing lens 33 to focus.

  In step S204, it is determined whether or not the release switch 48 is turned on. If the release switch 48 is not turned on (NO in step S204), the process returns to step S202 to wait for the AF switch 47 to be turned on again.

  When the release switch 48 is turned on (YES in step S204), the first mirror 12 and the second mirror 13 are retracted from the photographing optical system in step S205. That is, the mirror unit 11 (the first mirror 12 and the second mirror 13) is temporarily in the mirror-up state.

  In step S206, the shutter 14 is temporarily opened and the image sensor 16 is temporarily exposed.

  In step S207, a still image is photographed by the image sensor 16.

  In step S208, the shutter 14 is closed and the still image shooting is terminated. That is, the photographing of the still image by the image sensor 16 is finished.

  In step S209, the first mirror 12 and the second mirror 13 are restored. That is, the mirror unit 11 (the first mirror 12 and the second mirror 13) returns to the mirror-down state.

  As described above, the first embodiment has the following effects.

(1) In the moving image shooting mode, the focusing lens 33 is moved and held at a predetermined position (infinite focus position), and the imaging device 16 is moved by the actuator 17 to be focused by contrast AF. Thereby, it is possible to shoot a moving image with less noise. Further, the amount of movement of the image sensor is reduced, and the focusing time is shortened.

(2) In the still image shooting mode, the imaging device 16 is moved and held at a predetermined position (conventional imaging position), and the focusing lens 33 is moved to focus by phase difference AF. This eliminates the problem that the focusing range of the focusing lens 33 is narrowed.

[Deformation]
The present invention is not limited to the above-described embodiment, and various modifications and changes as described below are possible, and these are also within the scope of the present invention.

  In the first embodiment, the present invention is configured by the digital camera 1 including the camera body 10 and the lens barrel 30 that is detachably attached to the camera body 10. However, the present invention is not limited to this, and the present invention may be configured by the camera body 10 to which the lens barrel 30 is not attached.

  In addition, although 1st Embodiment and modification can also be used in combination suitably, detailed description is abbreviate | omitted. Further, the present invention is not limited by the embodiments described above.

  1: digital camera, 10: camera body (camera body), 11: mirror unit, 12: first mirror, 13: second mirror, 14: shutter, 15: imaging unit, 16: imaging device, 17: actuator, 18 : Imaging element regulating member, 19: monitor (image display unit), 20: finder unit, 21: finder screen, 22: pentaprism, 23: eyepiece, 24: AF module, 25: AF motor, 26: microphone, 30: Lens barrel, 31: photographing lens (optical member), 32: fixed lens, 33: focusing lens, 34: focusing lens driving mechanism, 40: control means (camera control unit, camera CPU), 41: imaging element driving Circuit: 42: AFE (Analog Front End) circuit, 43: A / D converter, 44: ASIC (image processing circuit), 45: Image display circuit, 46: Motion Image mode switch, 47: AF switch, 48: Release / Movie switch, 51: AF circuit, 52: AF lens drive circuit, 53: Mirror drive circuit, 54: Shutter drive circuit, 55: Actuator drive circuit

Claims (11)

An imaging unit capable of capturing a moving image of a subject image formed by an optical member;
A driving member that moves the imaging unit along the optical axis of the optical member to focus the subject image on the imaging unit;
A digital camera body comprising: a control unit configured to move and focus the imaging unit by the driving member with respect to the optical member held at a predetermined position. The digital camera body according to claim 1,
Digital camera body with a microphone for recording during movie shooting. The digital camera body according to claim 1 or 2,
The digital camera body characterized in that the imaging unit can switch between still image shooting and moving image shooting. The digital camera body according to any one of claims 1 to 3,
The control means uses the imaging unit as a front end with respect to the optical member held at the infinity in-focus position with an image plane position where a subject image is formed when the optical member is at the infinity in-focus position. A digital camera body characterized by being moved. An optical member;
An imaging unit capable of capturing a moving image of a subject image formed by the optical member;
A driving member that moves the imaging unit along the optical axis of the optical member to focus the subject image on the imaging unit;
A digital camera comprising: control means for moving the imaging unit with the driving member to focus on the optical member held at a predetermined position. The digital camera according to claim 5,
A digital camera with a microphone for recording during movie recording. The digital camera according to claim 5 or 6,
The digital camera according to claim 1, wherein the imaging unit can switch between still image shooting and moving image shooting. The digital camera according to any one of claims 5 to 7,
The control means provides an image plane on which the subject image is formed when the optical member is at the infinite focus position with respect to the optical member held at the infinite focus position during moving image shooting. A digital camera that is moved with its position at the front end. The digital camera according to claim 7,
The digital camera according to claim 1, wherein the control unit moves the optical member to focus on the imaging unit held at a predetermined position during still image shooting. The digital camera according to claim 9,
The control means moves the optical member behind the imaging unit held at the image plane position, and an infinite focus position where an infinite subject image is formed when the imaging unit is at the image plane position. A digital camera characterized by being moved as an end. The digital camera according to claim 7,
The control means includes
At the time of moving image shooting, with respect to the optical member held at the infinity in-focus position, the image pickup unit is driven by the driving member, and the image plane position on which the subject image is formed when the optical member is at the infinity in-focus position Move as the front end to focus,
At the time of still image shooting, the infinity focusing position where the optical member is formed on the imaging unit held at the image plane position, and an infinite subject image is formed when the imaging unit is at the image plane position. A digital camera characterized in that the camera is moved as a rear end to be focused.

Images