JP2014022799A - Image pickup device and image pickup method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pickup device and image pickup method capable of keeping a change state of subject light by an optical filter constant without being affected by a change of the posture.SOLUTION: A digital camera (image pickup device) 1 is configured from an optical system 21, an image sensor 23, an optical filter 30, an optical filter rotation drive unit 31, an optical filter rotation angle detection unit 32, an acceleration sensor (posture detection unit) 28, and a main control unit 20, etc. When the posture of the digital camera 1 is changed, the main control unit 20 rotates the optical filter 30 by using the optical filter rotation drive unit 31 on the basis of an angle θ2 formed by an absolute reference axis I and a reference axis m of the digital camera 1 and an angle θ3 formed by the reference axis m and a reference axis n of the optical filter 30, so that an angle θ1 formed by the reference axis n of the optical filter 30 and the absolute reference axis I is kept constant.

Description

  The present invention relates to an imaging apparatus such as a digital still camera and a digital video camera, and an imaging method.

  2. Description of the Related Art Conventionally, in photography, there are cases where various optical filters are attached to the front surface of a lens and the like for photography in order to obtain a photographic expression closer to the user's intention to express. There is also a camera (imaging device) that incorporates these optical filters and can switch the effect of the optical filter internally depending on the situation. A typical example of such an optical filter is a polarized light (PL) filter. The polarizing filter has a property of transmitting only light having a specific vibration direction, and is used for the purpose of suppressing reflection of a glass window and a water surface and photographing a blue sky more blue. When photographing using the polarizing filter, the user rotates the polarizing filter while checking the live view display of the optical viewfinder or liquid crystal monitor mounted on the camera. Then, a polarizing filter is arranged at a rotation angle at which a polarization effect is obtained so that an image that best matches the user's expression intention or the like can be obtained. It is common to take a picture after adjusting the polarization effect in this way.

  However, when the user changes the posture (composition) of the camera with the polarizing filter attached, the user rotates to the polarizing filter together with the camera. For example, if you initially shoot with the camera mounted horizontally (horizontal position) with a polarizing filter attached, and then shoot the same subject with the camera held vertically (vertical position) And the polarizing filter is rotated 90 degrees. As a result, the polarization effect of the polarization filter on the subject changes, so that an image different from that intended by the user may be obtained.

  Therefore, in order to acquire an image that matches the shooting situation of the subject, the user's intention to draw, and the like, it is necessary to adjust the polarization effect of the polarization filter each time the camera posture is changed. Alternatively, it is necessary to devise such as changing the posture of the camera after fixing only the polarizing filter with one hand. This operation is troublesome for a user who changes the composition of the camera many times, and cannot concentrate on the determination of the composition, resulting in a problem that efficient imaging cannot be performed.

  In addition, the prior art which adjusts the angle of a change filter in the state which fixed the composition, and focuses with a desired light quantity is known (for example, refer patent document 1). In the prior art described in Patent Document 1, the polarizing filter is rotated in a state where the composition of the camera is fixed, for example, when the camera is activated and a through image is displayed on the image display unit. The amount of light that changes with this rotation is associated with the evaluation value at the time of focusing (hereinafter, this evaluation value is referred to as “PL evaluation value”). A correspondence graph between the PL evaluation value and the rotation angle of the polarizing filter is displayed on the image display unit together with the through image. Based on the through image and the corresponding graph, the user selects an appropriate PL evaluation value according to the shooting situation of the subject and the drawing intention. Based on the selected PL evaluation value, the rotation angle is determined from the corresponding graph, and the polarization filter is rotationally driven.

  However, the prior art of Patent Document 1 is for automatically rotating the polarizing filter with the camera composition fixed and adjusting the amount of light, and for controlling the rotation of the polarizing filter corresponding to the composition change. Is not disclosed.

  The present invention has been made in view of the above circumstances, and when the subject light reaching the image sensor is changed by the optical filter in accordance with the shooting purpose such as the shooting situation of the subject or the intention of drawing, the camera body is thereafter An object of the present invention is to provide an imaging apparatus and an imaging method capable of maintaining the effect of the optical filter constant even if the posture of the camera changes.

  In order to achieve the above-described object, an image pickup apparatus according to the present invention receives an object light incident through an optical apparatus main body, an optical system, and converts the light into an electric signal to output it as an image pickup signal. An optical filter that rotates around the optical axis of the optical system, an optical filter rotation driving unit that rotates the optical filter, an attitude detection unit that detects attitude information of the imaging apparatus body, and an imaging apparatus Based on the posture information of the main body, the optical filter rotation drive unit is controlled to rotate the optical filter, and the first axis extending in the vertical direction through the optical axis in a plane orthogonal to the optical axis and orthogonal to the optical axis And an optical filter angle adjustment unit that maintains a constant angle between a predetermined position of the optical filter and a second axis that passes through the optical axis within the plane.

  According to the present invention, when the subject light passing through the optical filter is changed by rotating an optical filter such as a polarizing filter in accordance with the photographing purpose of the subject and the photographing purpose such as the user's drawing intention, Even when the posture of the imaging device such as a camera is changed, an imaging device and an imaging method capable of maintaining the change state of the subject light by the optical filter can be obtained. As a result, a subject image that matches the shooting situation of the subject and the user's intention to draw can be obtained without being affected by a change in posture of the imaging apparatus such as a change in composition, and more efficient and good shooting is possible.

It is a schematic diagram which shows the structure of the digital still camera as an imaging device which concerns on 1st Example, (a) represents a front view, (b) represents a top view, and (c) represents a rear view. FIG. 2 is an explanatory block diagram illustrating functions executed by the digital camera shown in FIG. 1. It is a schematic diagram which shows the optical filter rotation drive part and optical filter rotation angle detection part which were mounted in the digital camera which concerns on 1st Example. It is explanatory drawing for demonstrating a mode that the image image | photographed changes with the rotation angles of a polarizing filter, (a) shows an image when rotating a polarizing filter by a predetermined angle, (b), An image when the polarizing filter is rotated at an angle different from (a) is shown. It is explanatory drawing for demonstrating the adjustment procedure of the rotation angle of the optical filter in the digital camera of 1st Example, (a) shows the normal attitude | position (basic attitude | position) of a digital camera, (b) is a digital camera. 2 shows a state in which the orientation of the digital filter is changed from the normal orientation and the rotation angle of the optical filter is set by manual operation, (c) shows the case where the orientation of the digital camera is further changed, and (d) shows the optical filter The rotation angle of is automatically adjusted. It is a flowchart which shows an example of the live view process of the imaging method implemented with the digital camera shown in FIG. It is a schematic diagram which shows the optical filter rotation drive part and optical filter rotation angle detection part which were mounted in the digital camera which concerns on 2nd Example.

<First embodiment>
The imaging apparatus according to the first embodiment of the present application will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a hardware configuration of a digital still camera (hereinafter referred to as “digital camera”) 1 as an example of an imaging apparatus according to the present embodiment. FIG. 2 is a block explanatory diagram of functions executed by the digital camera 1 shown in FIG. FIG. 3 is a schematic diagram illustrating the configuration of the optical filter rotation drive unit 31 and the optical filter rotation angle detection unit 32 mounted on the digital camera 1 according to the first embodiment.

(Appearance structure of digital camera)
The external configuration of the digital camera 1 will be described with reference to FIG. As shown in FIG. 1, the horizontal direction is defined as the x-axis, the vertical direction is defined as the y-axis, and the optical axis direction of the optical system is defined as the z-axis. As shown in FIG. 1B, a shutter release button 2, a power button 3, and a shooting / playback switching dial 4 are provided on the upper surface side of the digital camera 1 of the present embodiment. As shown in FIG. 1A, on the front (front) side of the digital camera 1, a lens barrel unit 6 (main imaging optical system) having a photographing lens system 5 including a plurality of lens groups, a diaphragm and the like, strobe light emission. A unit (flash) 7 and an optical finder 8 are provided. As shown in FIG. 1C, on the back side of the digital camera 1, a liquid crystal monitor (LCD) 9, an eyepiece 8a of an optical viewfinder 8, a wide-angle zoom (W) switch 10, a telephoto zoom ( T) A switch 11, a menu (MENU) button 12, a confirmation button (OK button) 13, and various operation buttons (flash, function buttons, etc.) 16 are provided. Further, a memory card storage unit 15 for storing a memory card 14 (see FIG. 2) for storing captured image data is provided inside the side surface of the digital camera 1.

(Functional block of digital camera 1)
FIG. 2 shows an example of functional blocks (system configuration) of the digital camera 1 used in this embodiment. The digital camera 1 of the present embodiment includes a main control unit 20, an optical system 21, an optical system drive unit 22, an image sensor 23, an A / D conversion unit 24, a liquid crystal display unit 25, an external I / F 26, a storage unit 27, and an acceleration. A sensor (attitude detection unit) 28, an optical filter 30, an optical filter rotation drive unit 31, an optical filter rotation angle detection unit 32, and the like are configured. In the present embodiment, the main control unit 20, the optical filter rotation angle detection unit 32, and the like also function as an optical filter angle adjustment unit for adjusting the rotation angle of the optical filter 30.

  Here, the main control unit 20 includes a CPU and its peripheral circuits, and includes mechanical drive control, electrical drive control, and various image processing, liquid crystal related to various operations in the digital camera 1 of the present embodiment. Various controls such as display control, memory control, and external communication are performed. The optical system 21 includes a photographic lens system 5 (see FIG. 1) including a plurality of lens groups, a diaphragm, and the like, and forms a subject (field of view) image on the image sensor 23. The image sensor 23 performs processing for converting image data imaged by the optical system 21 into an analog electric signal. The A / D converter 24 performs a process of converting an image signal composed of an analog electric signal output from the image sensor 23 into an image signal composed of a digital electric signal. Further, under the control of the main control unit 20, the image signal composed of the digital signal input from the A / D conversion unit 24 is subjected to predetermined image processing in the liquid crystal display unit 25 and converted into image data, If necessary, it is displayed on a liquid crystal monitor (LCD) 9.

  The optical system drive unit 22 is controlled by the main control unit 20 and performs focusing adjustment, that is, focus adjustment, by moving the optical system 21 along the optical axis direction of the optical system 21. In addition, the main control unit 20 may have a function of detecting the in-focus state by performing contrast analysis or the like based on the image data acquired by the image sensor 23.

  The storage unit 27 includes a RAM, a ROM, and the like. The storage unit 27 stores image data that has been imaged by the image sensor 23 and that has undergone predetermined image processing under the control of the main control unit 20. The storage unit 27 also stores control program data related to the operation of the main control unit 20, temporary storage data including intermediate data related to various control processes, and the like.

  The main control unit 20 also includes a memory controller function for an external storage device (external memory) such as the memory card 14. Therefore, the main control unit 20 can write and read image data and the like to the external memory via the external I / F 26. Further, the main control unit 20 performs predetermined image processing on the image signal given through the optical system 21, the image pickup device 23, and the A / D conversion unit 24 when the subject is photographed, and the image data. After being converted to, it is displayed on the liquid crystal monitor 9. The operations of the image sensor 23, the A / D converter 24, the liquid crystal display unit 25, and the like shown in FIG. Further, as described above, the main control unit 20 uses the image information input from the optical system 21 to realize an autofocus function based on a contrast AF method by contrast analysis or the like, and controls the optical system driving unit 22 as needed. Focusing is done.

  The main control unit 20 stores the image data in the storage unit 27 when the shutter release button 2 is pressed. Further, the main control unit 20 displays the image data subjected to the conversion process by the liquid crystal display unit 25 on the liquid crystal monitor 9 for image confirmation, and external memory such as the memory card 14 via the external I / F 26. The image data is transferred and the image data is transferred.

  The acceleration sensor 28 is used as an attitude detection unit of the digital camera 1, detects the tilt, movement, vibration, impact, etc. of the digital camera 1 and sequentially outputs the detected data to the main control unit 20. The main control unit 20 acquires posture information of the digital camera 1 based on the sensing data sequentially transmitted from the acceleration sensor 28. Note that the posture detection unit is not limited to the acceleration sensor 28, and any one may be used. However, since the acceleration sensor 28 is often mounted as a standard in a digital camera for applications such as an electronic level, in the first embodiment, the acceleration sensor 28 mounted as a standard is also used as an attitude detection unit. Yes. By using the existing device in this way, it is not necessary to provide a new sensor or the like as the posture detection unit, and the cost can be reduced and the digital camera 1 can be made compact.

  As the optical filter 30, in the first embodiment, a polarizing filter that transmits only a specific polarization component of the subject light by rotation adjustment with the optical axis of the optical system 21 as the central axis is used. The optical filter 30 is rotationally driven in the circumferential direction about the optical axis of the optical system 21 by the optical filter rotation drive unit 31 automatically or manually by the user. The operation of the optical filter rotation drive unit 31 is controlled by the main control unit 20. The rotation angle of the optical filter 30 with respect to the digital camera 1 when the optical filter 30 rotates is detected by the optical filter rotation angle detector 32. The optical filter rotation angle detection unit 32 transmits the detected rotation angle data to the main control unit 20. Further, a knob portion 303 is provided on the outer periphery of the optical filter 30 as a clue when the optical filter 30 is rotated.

  FIG. 5A shows a normal posture in which the digital camera 1 is held horizontally, and this normal posture is set as a basic posture of the digital camera 1. FIG. 5B shows a state in which the user holds the digital camera 1 in a desired posture and the optical filter 30 is rotated about the optical axis of the optical system 21 so that the desired polarization effect can be obtained. Show. FIG. 5C shows a state in which the user further changes the posture of the digital camera 1. An absolute reference axis (absolute reference axis 1 described later) extending in the vertical direction through the optical axis of the optical system 21 in a plane orthogonal to the optical axis of the optical system 21 is used as a reference, and the optical filter 30 with respect to the absolute reference axis is used as a reference. The rotation angle changes from the rotation angle set by the user in FIG. FIG. 5D shows the absolute reference axis set by the user in FIG. 5B when the posture of the digital camera 1 shown in FIG. 5C is changed from the posture shown in FIG. A state in which the optical filter 30 is rotated so that the rotation angle of the optical filter 30 as a reference is maintained is shown. In describing each process of adjusting the rotation angle of the optical filter 30, an absolute reference axis, a reference axis, and an angle are defined as follows.

[Definition of reference axis]
In the normal posture (basic posture) of the digital camera 1, an axis that extends directly upward (vertical direction) from the lens center, that is, in a plane orthogonal to the optical axis of the optical system 21 and extends in the 12 o'clock direction is absolute. Let it be a reference axis l. The absolute reference axis l is not affected by the rotation of the digital camera 1 or the optical filter 30 and does not tilt.

  The reference axis n of the optical filter 30 for detecting the rotation angle of the optical filter 30 is a line that is in the same plane as the absolute reference axis l and connects the center of the optical filter 30 and the knob portion 303 of the optical filter 30. And The reference axis n of the optical filter 30 rotates with rotation about the optical axis of the optical system 21 as the central axis.

  The direction at 12 o'clock from the lens center in the normal posture is set as the reference axis m of the digital camera 1. The reference axis m of the digital camera 1 also rotates with the optical axis of the optical system 21 as the central axis as the posture of the digital camera 1 changes.

  Here, the reference axis n of the optical filter 30 is determined with reference to the knob portion 303. However, the knob portion 303 is taken into consideration when the knob portion 303 is not provided or in consideration of design intent and operability. May be provided at a position such as 45 ° or 90 ° with respect to the central axis m. Therefore, it is not always necessary to determine the reference axis n of the optical filter 30 with reference to the knob portion 303. On the circumference of the optical filter in a state where the optical filter 30 is set in the digital camera 1 and is not rotated. A line connecting one point and the center of the optical filter may be determined as the reference axis n of the optical filter 30. That is, it is only necessary to know the rotation angle of the optical filter 30 with respect to the absolute reference axis l and the reference axis m of the digital camera 1.

[Definition of angle θ1]
As shown in FIG. 5A, the state in which the knob portion 303 of the optical filter 30 is disposed at a position where the absolute reference axis l and the reference axis n of the optical filter 30 coincide with each other is the initial state of the optical filter 30 with respect to the digital camera 1. The initial position of the reference axis n at this time is n0. The angle formed by the absolute reference axis 1 and the reference axis n of the optical filter 30 is θ1. 5A, the angle θ1 formed by the absolute reference axis l and the reference axis n0 is 0 degree.

[Definition of angle θ2]
An angle formed by the absolute reference axis l and the reference axis m of the digital camera 1 is an angle θ2. The reference axis when the digital camera 1 shown in FIG. 5A is in the normal posture (basic posture) is m0, and in this normal posture, the angle θ2 formed by the absolute reference axis l and the reference axis m0 is 0 degree. It becomes.

[Definition of angle θ3]
An angle formed by the reference axis m of the digital camera 1 and the reference axis n of the optical filter 30 is an angle θ3 (relative angle). As shown in FIG. 5A, when the digital camera 1 is in the normal posture (basic posture) and the optical filter 30 is located at the initial position, the angle θ3 formed by the reference axis m0 and the reference axis n0 is 0 degree. It becomes.

(Configuration and operation of optical filters, etc.)
The schematic configuration and operation of the optical filter 30, the optical filter rotation drive unit 31, and the optical filter rotation angle detection unit 32 will be described with reference to the schematic diagram shown in FIG. First, since the subject light needs to be projected onto the image sensor 23 through the lens of the optical system 21 and the optical filter 30, these are aligned on the optical axis of the optical system 21. In the first embodiment, the optical filter 30 is configured to be detachably attached to the lens barrel unit 6 in which the optical system 21 is housed. With this configuration, the optical filter 30 is disposed between the optical system 21 and the image sensor 23, and the optical filter 30 and the image sensor 23 are located close to each other. The optical filter 30 is configured to be rotatable about the optical axis of the optical system 21 as a central axis, independently of the optical system 21.

  As described above, in the first embodiment, as shown in FIG. 3, the optical filter 30 is disposed between the optical system 21 and the imaging device 23, but the optical filter 30 and the optical system 21 are not necessarily in such a manner. It is not limited to the positional relationship. For example, as another different embodiment, the optical filter 30 and the optical system 21 are interchanged, and the optical system 30 is disposed between the optical filter 30 and the image sensor 23, thereby separating the optical filter 30 and the image sensor 23. May be arranged.

  As shown in FIG. 3, the optical filter 30 has a filter main body 301 formed of a polarizing filter. The optical filter 30 further includes a gear portion (gear) 302 having a plurality of teeth 302 a formed on the outer periphery of the filter main body 301. Further, the gear portion 302 is engaged with a pinion gear 311 having a smaller diameter than the gear portion 302 and having a plurality of teeth 311a. The pinion gear 311 can be rotated by a drive unit (not shown) such as a motor. In the first embodiment, the optical filter rotation drive unit 31 includes a gear unit 302 of the optical filter 30, a pinion gear 311, a drive unit (not shown) of the pinion gear 311, and the like.

  The optical filter rotation angle detection unit 32 includes a rotation angle sensor such as a rotary encoder. The optical filter rotation angle detection unit 32 detects the rotation direction and rotation angle of the pinion gear 311 with a rotation sensor, and transmits this detection data to the main control unit 20.

  When the optical filter 30, the optical filter rotation drive unit 31, and the optical filter rotation angle detection unit 32 configured as described above are rotated to a desired angle with the center of the optical filter 30 as a rotation axis according to the photographing purpose. The pinion gear 311 engaged with the gear portion 302 of the optical filter 30 rotates. The optical filter rotation angle detection unit 32 detects the rotation angle of the pinion gear 311 with respect to the initial position, and transmits the detection data to the main control unit 20. Based on this detection data, the main control unit 20 can acquire the rotation angle of the optical filter 30 (the angle θ1 formed by the absolute reference axis 1 and the reference axis n) set by the user. Therefore, the gear unit 302 of the optical filter 30 also has a function as an angle setting unit for acquiring a desired rotation angle of the optical filter 30 input by the user. Further, the angle θ3 formed by the reference axis m of the digital camera 1 and the reference axis n of the optical filter at this time is mechanically stored in the pinion gear 311 engaged with the gear unit 302.

  In the first embodiment, as the optical filter rotation driving unit 31, a simple one including a gear unit 302, a pinion gear 311 and a motor is used. However, the present application is not limited to this, and any other mechanism may be used as the optical filter rotation driving unit 31 as long as the optical filter 30 can be rotated. The optical filter rotation angle detection unit 32 also uses a rotation angle sensor such as a rotary encoder, but the present application is not limited to this, and any other means may be used.

(Polarization effect of polarizing filter)
Next, the polarization effect (change in subject light) by the polarization filter will be described with reference to FIG. FIG. 4 simply shows an example of the effect of changing the subject light passing through the polarizing filter by rotating the polarizing filter and giving it to the photographed image. Even when attempting to shoot the same subject with the same composition, when the polarizing filter is set at a certain rotation angle, the landscape (mountain and clouds) behind the pond is shown in FIG. An image reflected on the surface of the film is obtained. On the other hand, when the polarizing filter is set to a rotation angle different from that in FIG. 4A, the subject light incident on the optical system 21 is reflected by the water surface as shown in FIG. 4B. Since the polarized light is blocked by the polarizing filter, the reflected light incident on the image sensor 23 is suppressed, and an image in which the transparency of the pond is emphasized (image on which the fish is projected) is obtained.

  As described above, by rotating the optical filter 30 with the optical axis of the optical system 21 as the central axis, it is possible to obtain a polarization effect according to the photographing purpose such as the photographing situation and the drawing intention. In this embodiment, the rotation angle of the optical filter 30 is as follows in order to maintain the polarization effect constant and perform efficient and good imaging without being affected by the change in the posture of the digital camera 1. The adjustment process is performed.

(Optical filter rotation angle adjustment processing)
An angle adjustment process of the optical filter 30 in photographing a subject with the digital camera 1 of the first embodiment will be described with reference to FIGS. 5 and 6 described above. FIG. 6 shows a flow of processing in the main control unit 20 of an operation (live view) for displaying an image acquired by the image sensor 23 in real time on the liquid crystal monitor 9 after converting the image data into image data by the liquid crystal display unit 25. It is a flowchart.

[Explanation of live view processing]
The operation of live view processing using the digital camera 1 of the first embodiment shown in FIGS. 1 to 3 will be described below with reference to the flowchart of FIG.

<Acquisition processing of initial value of angle θ3>
When the live view is started by starting the digital camera 1, the main control unit 20 first obtains an angle θ3 formed by the reference axis m of the digital camera 1 and the reference axis n of the optical filter 30 (step S1). The angle θ3 is calculated by the main control unit 20 based on the rotation angle of the pinion gear 311 transmitted from the optical filter rotation angle detection unit 32. In the example shown in FIG. 5B, the posture of the digital camera 1 is changed from the normal posture, and the optical filter 30 is also rotated. Therefore, in this process, an angle θ3 formed by the reference axis m1 of the digital camera 1 and the reference axis n1 of the optical filter 30 is acquired. The angle θ3 is mechanically stored in the pinion gear 311 but may be stored as data in the storage unit 27, an external memory, or the like. By storing the data in the storage unit 27 and the like, it is possible to reliably maintain θ1 constant by using θ3 of the storage unit 27 and the like regardless of the rotation angle of the pinion gear 311.

<An angle θ2 acquisition process>
Next, the main control unit 20 acquires the angle θ2 formed by the absolute reference axis l and the reference axis m of the digital camera 1, and stores it in the storage unit 27 or the like (step S2). The angle θ2 is calculated by the main control unit 20 based on the attitude information of the digital camera 1 transmitted from the acceleration sensor 28. This step S2 is performed regardless of whether or not the posture of the digital camera 1 has been changed, and the current posture information of the digital camera 1 is acquired. Further, the processing after step S2 is repeated not only when the digital camera 1 is activated but also at predetermined intervals while the live view is being executed.

<Optical filter manual operation presence / absence determination process>
Next, the main controller 20 uses the optical filter rotation angle detector 32 to determine whether or not the optical filter 30 is being rotated by the user (step S3). If it is determined that the rotation operation is being performed, the process proceeds to step S4. If it is determined that the rotation operation is not being performed, the process proceeds to step S6.

  A procedure for determining whether or not the rotation operation is being performed will be described with reference to FIGS. In order to obtain a desired polarization effect, as shown in FIG. 5B, the user manually rotates the optical filter 30 about the optical axis of the optical system 21 as the central axis. By the user's manual operation, the gear portion 302 of the optical filter 30 rotates and the reference axis n moves from n0 to n1. That is, as described above, the gear unit 302 also has a function as an angle setting unit for the user to input (set) the rotation angle of the optical filter 30 as desired. Along with the rotation of the gear unit 302, the pinion gear 311 of the optical filter rotation driving unit 31 engaged with the gear unit 302 rotates. The rotation angle of the pinion gear 311 is detected by the optical filter rotation angle detector 32 and transmitted to the main controller 20. The main control unit 20 can recognize that the angle between the reference axis m of the digital camera 1 and the reference axis n of the optical filter 30 has changed due to the rotation of the pinion gear 311. In this case, the rotation is being performed. Is determined. Alternatively, the stored angle θ3 (0 degree at the initial position) is compared with the currently acquired angle with reference to the storage unit 27, and it is determined that the optical filter 30 is being rotated when there is a change. May be. On the other hand, in any determination method, when the angle θ3 does not change, it is determined that the rotation operation is not being performed.

<Acquisition processing of angle θ3 during rotation operation>
If it is determined in step S3 that the rotation operation is being performed, then the processes in steps S4 and S5 are performed. “Rotating operation” means that the user has manually set the optical filter 30 at a desired angle so as to obtain a desired polarization effect, as shown in FIG. 5B. In step S4, the main controller 20 determines the reference axis m (m1) of the digital camera 1 and the reference axis n (n1) of the optical filter 30 after manual operation based on the detection data from the optical filter rotation angle detector 32. An angle θ3 formed by the two is acquired. The acquired angle is mechanically stored in the pinion gear 311 as θ3 at the time when the rotation operation is performed. Alternatively, θ3 may be stored (updated) in the storage unit 27 or the like. In acquiring the angle θ3 in step S4, the angle θ3 acquired when determining the rotation operation of the optical filter 30 in step S3 may be used.

<Angle θ1 acquisition processing>
Once the angle θ3 formed by the reference axis 1 of the optical filter 30 and the reference axis n of the digital camera 1 is obtained, the process proceeds to step S5, and the absolute reference axis 1 and the optical filter 30 are expressed using the following equation (1). An angle θ1 formed by the reference axis n (n1) is calculated and stored in the storage unit 27 or the like. The angle θ1 can be calculated by the following equation (1) if θ2 and θ3 are known. Therefore, the angle θ1 may be stored only in a temporary memory or may not be stored. An angle θ1 formed by the absolute reference axis l and the reference axis n (n1) of the optical filter 30 is a rotation angle of the optical filter 30 with respect to the subject (used in processes in steps S6 to S8 described later). In the following formula (1), θ2 is the angle formed by the absolute reference axis 1 and the reference axis m (m1) of the digital camera 1 acquired in step S2, and θ3 is the digital camera acquired in step S3. 1 shows an angle formed by one reference axis m (m1) and a reference axis n (n1) of the optical filter 30.

θ1 = θ2 + θ3 (1)

  In the digital camera 1 whose posture (composition) is determined at the angle θ2 as described above, the optical filter 30 in which the angle between the absolute reference axis l and the reference axis n of the optical filter 30 is set to θ1 by the user. Then, the image of the subject is acquired by the image sensor 23. The image acquired by the image sensor 23 is subjected to predetermined image processing by the liquid crystal display unit 25 and then displayed on the liquid crystal monitor 9 (live view). Next, the process proceeds to step S9 to determine whether to continue the live view.

<Adjustment process of angle θ3>
If it is determined in step S3 that the rotation operation is not being performed, the following steps S6 to S8 are performed. If the optical filter 30 is not being rotated, the rotation angle of the optical filter 30 from the absolute reference axis l is determined, and it is necessary to maintain this rotation angle constant regardless of the change in the attitude of the digital camera 1. Means that. As shown in FIG. 5C, the position of the optical filter 30 is changed from the position n1 to the position n2 in a state where the reference axis n of the optical filter 30 forms an angle with the reference axis m of the digital camera 1 as the attitude of the digital camera 1 is changed. Move to. Therefore, the rotation angle of the optical filter 30, that is, the angle formed by the absolute reference axis and the reference axis n (n2) also changes from θ1 to θ1 ′, so that the polarization effect by the optical filter 30 also changes. Therefore, by performing the automatic adjustment such that the reference axis n2 is returned to the position n1 and θ1 ′ is returned to θ1, the polarization effect can be maintained constant and excellent optical characteristics can be obtained. The automatic adjustment procedure will be described below.

  First, in step S6, the difference Δθ (angle change amount) between the angles θ2 and θ2 ′ formed by the absolute reference axis 1 and the reference axis m before and after the attitude change of the digital camera 1 is calculated using the following equation (2). To do. In the following equation (2), θ2 ′ represents an angle formed by the absolute reference axis l and the reference axis m after the posture change, and θ2 represents an angle formed by the absolute reference axis l and the reference axis m before the posture change. In FIG. 5C, θ2 ′ is an angle formed by the absolute reference axis 1 and the reference axis m2 after the posture change, and θ2 is the absolute reference axis l and the reference axis m1 in FIG. 5B before the posture change. Is the angle formed by

Δθ = θ2′−θ2 (2)

  Next, in step S7, the optical filter 30 is rotated by Δθ calculated by the above equation (2) to return the rotation angle of the optical filter 30 desired by the user. For this purpose, the main control unit 20 drives the optical filter rotation drive unit 31 while monitoring the rotation angle of the optical filter 30 from the optical filter rotation angle detection unit 32 (actually, the rotation angle of the pinion gear 311), and Δθ The optical filter 30 is rotated at an angle of. More specifically, when the attitude of the digital camera 1 is changed in the clockwise direction, the optical filter 30 is rotated counterclockwise by | Δθ |, and the attitude of the digital camera 1 is changed in the counterclockwise direction. In this case, the optical filter 30 is rotated clockwise by | Δθ |. In FIG. 5D, the central axis n is rotationally moved from n2 to n3. If the optical filter 30 is configured to automatically rotate in only one direction according to mechanical specifications or design specifications, the optical filter 30 can be rotated by “360 degrees−Δθ”. In this case, the optical filter 30 can be returned to the original position.

  At this time, as shown in FIG. 5D, the angle θ3 ″ formed by the reference axis m2 of the digital camera 1 after the angle adjustment and the reference axis n3 of the optical filter 30 is a new angle for calculating the rotation angle θ1. As θ3, it is memorized mechanically in the pinion gear 311 or as data in the storage unit 27 (step S8), and is used for determination of presence / absence of the next rotation operation and angle adjustment. θ3 ″ is obtained by the following equation (3). And can be calculated logically.

θ3 ″ = θ3′−Δθ (or can be calculated from θ1−θ2 ′)
= Θ3− (θ2′−θ2) (3)

<Determining whether to continue live view>
Finally, in step S9, it is determined whether or not to interrupt the live view. For example, when there is a request for shooting by pressing the shutter release button 2, when there is a request for image reproduction by switching the shooting / playback switching dial 4, when there is a request for turning off the power by operating the power button 3, etc. When there is a processing request other than the live view, it is determined that the live view is interrupted. When these processing requests are not present, it is determined that the live view is continued.

  If it is determined that the live view is to be interrupted, the entire live view process is terminated. On the other hand, when it determines with continuing a live view, it returns to step S2 and repeats the process of step S2-S8. That is, when the user further changes the attitude of the digital camera 1 during live view, the angle θ2 formed by the changed absolute reference axis 1 and the reference axis m of the digital camera 1 after the attitude change is determined in step S2. To be acquired. Thereafter, the processes of S3 and S6 to S8 are performed, and the automatic adjustment of the rotation angle of the optical filter 30 is performed based on the difference Δθ before and after the posture change of the angle formed by the absolute reference axis 1 and the reference axis m of the digital camera 1. Done.

  Further, when the user rotates the optical filter 30 and changes the rotation angle relative to the subject from the previous time, the processes of steps S4 and S5 are performed, and the absolute reference axis l after the rotation operation of the optical filter 30 is performed. The angle θ1 formed by the reference axis n is recalculated. Further, the angle θ3 formed by the reference axis n of the optical filter 30 and the reference axis m of the digital camera 1 in this set state is mechanically stored in the pinion gear 311. Further, the angle θ2 formed by the absolute reference axis 1 and the reference axis m of the digital camera 1 is also stored in the storage unit 27. Even if the attitude of the digital camera 1 is changed after the rotation angle of the optical filter 30 is reset, the angle θ1 (the rotation angle of the optical filter 30) formed by the absolute reference axis 1 and the reference axis n of the optical filter 30 is constant. Thus, the rotation angle of the optical filter 30 is adjusted so as to be maintained. In this way, the live view is continued in a state where the polarization effect set by the user is maintained without being affected by the change in the posture of the digital camera 1.

  Since the angle adjustment of the optical filter 30 is performed as described above, even if the orientation of the digital camera 1 is changed by the user, the rotation angle of the optical filter 30 (the absolute reference axis l and the optical axis is not affected by the change). The angle formed by the reference axis n of the filter 30), that is, the polarization effect on the subject light can be kept constant and live view can be performed.

[Description of Specific Example Using FIG. 5]
Next, the angle adjustment of the optical filter 30 will be described more specifically with reference to FIG. As described above, in the normal posture (reference axis m0) of the digital camera 1 in FIG. 5A, the angles θ1 ₀ , θ2 ₀ , and θ3 ₀ are all 0 degrees. The user determines the posture (composition) from the normal posture shown in FIG. 5A by rotating the digital camera 1 clockwise around the optical axis of the optical system 21 as shown in FIG. 5B. And The angle formed by the absolute reference axis 1 at this time and the reference axis m (m1) after the posture change is calculated based on the data of the speed sensor 28 and stored in the storage unit 27 as θ2. Further, the angle θ2 ₀ (= 0 degree) before the posture change is stored as the previous posture separately from θ2. At this time, since the optical filter 30 is not manually operated, the angle of the reference axis n of the optical filter 30 is adjusted so as to return to the position of n0, although not shown. By this angle adjustment, the angle formed by the absolute reference axis 1 and the reference axis n (n0) of the optical filter 30 is maintained at 0 degrees.

  Thereafter, as shown in FIG. 5B, it is assumed that the user rotates the optical filter 30 clockwise by manual operation to adjust the polarization effect of the subject light. At this time, an angle formed by the reference axis m1 of the digital camera 1 and the reference axis n (n1) of the optical filter 30 after manual operation is acquired by the optical filter rotation angle detection unit 32, and is mechanically transmitted to the pinion gear 311 as θ3. Alternatively, the data is stored in the storage unit 27 as data. The angle θ3 formed by the reference axis m of the digital camera 1 and the reference axis n of the optical filter 30 changes from the angle formed by m1 and n0 before manual operation to the angle formed by m1 and n1 after manual operation. The main control unit 20 determines that the rotation operation is being performed.

  Based on these angles θ2 and θ3, the angle (absolute angle) θ1 (= θ2 + θ3) formed by the absolute reference axis 1 and the reference axis n1 of the optical filter 30 is calculated using the above equation (1). Is done. Further, this angle θ1 is kept constant until the next manual operation is performed. The details will be described below with reference to FIGS. 5 (c) and 5 (d).

  Since the user performs an imaging process with a composition different from that in FIG. 5B, the digital camera 1 is further rotated clockwise, and the angle formed by the absolute reference axis 1 and the reference axis m2 is shown in FIG. Suppose that it is changed to θ2 ′ as shown. In this case, θ2 before the posture change is stored in the storage unit 27 together with the angle θ2 ′ after the posture change acquired based on the posture information from the angle sensor 28. θ2 ′ and θ2 are used later to calculate the difference before and after the posture change.

  By changing the posture of the digital camera 1, the optical filter 30 is rotated with the digital camera 1 while maintaining the angle θ 3 formed by the reference axis n and the reference axis m of the digital camera 1. As shown, the reference axis n is also rotated and moved to the position n2. The angle θ1 ′ formed by the reference axis n and the absolute reference axis 1 when rotated to n2 is different from the value of the angle θ1 desired by the user set in FIG. 5B. If this is the case, the polarization effect desired by the user cannot be obtained, so that the reference axis n2 shown in FIG. 5C matches the n3 shown in FIG. 5D (the same position as n1) as follows. Angle adjustment of the optical filter 30 is performed.

  First, based on detection data from the optical filter rotation angle detector 32, an angle θ3 ′ formed by the reference axis m2 of the digital camera 1 and the reference axis n2 of the optical filter 30 is acquired. As described above, when the optical filter 30 is not rotated, the reference axis n is rotated with the digital camera 1 while maintaining an angle with the reference axis m of the digital camera 1 relatively constant. Therefore, the angle θ3 ′ coincides with the angle θ3 in FIG.

  In order to adjust the rotation angle of the optical filter 30, the main control unit 20 first calculates the difference Δθ between the angle θ2 and the angle θ2 ′ shown in FIG. 5C using the above equation (2). . The optical filter 30 is automatically rotated counterclockwise by the difference Δθ by the optical filter rotation driving unit 31 with the optical axis of the optical system 21 as the central axis. By this rotation, as shown in FIG. 5D, the reference axis n of the optical filter 30 is arranged at the position of n3, that is, at the same position as n1, and the absolute reference axis 1 and θ1 ′ which are θ1 ′ The angle formed by the reference axis n (the rotation angle of the optical filter 30) returns to the original angle θ1. Therefore, even after the attitude of the digital camera 1 is changed, it is possible to perform imaging with the same polarization effect as in FIG.

  Here, the reason why the optical filter 30 should be rotated by the angle difference Δθ between the absolute reference axis 1 and the reference axis m before and after the attitude change of the digital camera 1 will be described. The difference Δθ ′ for returning θ1 ′ shown in FIG. 5C to θ1 can be calculated using the following equation (4).

Δθ ′ = θ1′−θ1 (4)

  In the above formula (4), the angle θ1 ′ can be calculated by the following formula (5) based on the above formula (1). Further, as described above, when there is no rotation operation, the angle θ3 before the posture change coincides with the angle θ3 ′ after the posture change, and therefore the following equation (6) is established.

θ1 ′ = θ2 ′ + θ3 ′ (5)
θ3 = θ3 ′ (6)

  By substituting the above formulas (5) and (6) into the above formula (4), the following formula (7) is derived.

Δθ ′ = (θ2 ′ + θ3 ′) − (θ2 + θ3)
= (Θ2′−θ2) + (θ3′−θ3)
= Θ2′−θ2 (7)

  From the above formula (2) and formula (7), the following formula (8) is established. Therefore, in order to return the angle formed by the absolute reference axis 1 and the reference axis n of the optical filter 30 from θ1 ′ to θ1, the optical filter 30 may be rotated by Δθ.

Δθ = Δθ ′ (8)

  As described above, in the imaging method using the digital camera 1 according to the first embodiment, the user can capture an image of a subject with a free composition while maintaining a desired optical effect. Therefore, the user can concentrate only on the determination of the composition, and more efficient imaging with excellent optical performance is possible.

  Further, according to the present embodiment, the angle θ3 formed by the reference axis n and the reference axis m is mechanically stored in the pinion gear 311. Further, unless the user manually rotates the optical filter 30, this θ3 Is kept constant, the relative angle between the digital camera 1 and the optical filter 30 does not change. The angle θ3 formed by the reference axis m and the reference axis n changes to θ3 ′ when the rotation angle of the optical filter 30 is changed by a user's manual operation, and the absolute reference axis l and the reference axis n are formed. When the angle (rotation angle) is adjusted, it changes to θ3 ″. These new θ3 ′ and θ3 ″ are mechanically stored in the pinion gear 311 and the like, and thereafter, the stored angle becomes a reference. The rotation angle of the optical filter 30 is adjusted. Therefore, if the angle θ2 formed by the absolute reference axis 1 and the reference axis m of the digital camera 1, that is, the posture information from the speed sensor 28 is known, the angle (rotation angle) formed by the absolute reference axis 1 and the reference axis n is obtained. Can be kept constant. As described above, in this embodiment, the rotation angle of the optical filter 30 can be adjusted with high accuracy with a simple configuration.

  In the first embodiment, the case where the polarization filter is used as the optical filter 30 has been described. However, the present invention can be applied to the case where another optical filter is used.

  In the first embodiment, the normal posture in which the digital camera 1 is horizontally held in the horizontal direction and also in the front-rear direction and the optical axis of the optical system 21 is also set as the reference posture. Therefore, the center line in the y-axis direction passing through the lens center of the digital camera 1 and the absolute reference axis l are also coincident with the vertical axis. However, in the present application, the absolute reference axis 1 is not limited to the vertical axis. For example, when the digital camera 1 is held obliquely upward, the center line of the digital camera 1 is also inclined and intersects the vertical axis. An axis parallel to the oblique center line may be used as an absolute reference axis l, and the reference axis m of the digital camera 1 and the reference axis n of the optical filter 30 may be determined in the same plane as the absolute reference axis l. Further, when the digital camera 1 is held directly above or directly below, the optical axis of the optical system 21 coincides with the vertical axis, and the center line coincides with the horizontal axis. Therefore, this horizontal axis may be used as the absolute reference axis l. Whichever is set as the absolute reference axis l, it is only necessary to be able to grasp the rotation angle of the optical filter 30 with the optical axis of the optical system 21 with respect to the absolute reference axis l as the central axis.

<Second embodiment>
Next, a digital camera according to the second embodiment will be described. The basic configuration of the digital camera according to the second embodiment has the same configuration as that of the first embodiment except that the configuration of the optical filter rotation driving unit is changed. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. The optical filter rotation drive unit 31 ′ of the second embodiment will be described with reference to FIG.

  Reference numeral 30 ′ shown in FIG. 7 denotes an optical filter mounting portion, and various optical filters can be detachably mounted on the inner mounted portion 304. In the second embodiment, a gear portion 302 'having a plurality of teeth 302a' is provided on the outer periphery of the optical filter mounting portion 30 '. A pinion gear 311 having a smaller diameter than the gear portion 302 ′ and having a plurality of teeth 311 a is engaged with the gear portion 302 ′. As described above, in the second embodiment, the optical filter rotation drive unit 31 ′ is replaced with the gear unit 302 ′ of the optical filter mounting unit 30 ′, the pinion gear 311, the drive unit (not shown) of the pinion gear 311, and the like. Consists of.

  As described above, in the second embodiment, the gear portion 302 ′ is provided not in the optical filter itself but in the optical filter mounting portion 30 ′ for mounting the optical filter. And this gear part 302 'is used as a member of the angle setting part for setting the angle of an optical filter, or an optical filter rotation drive part. Therefore, a conventional appropriate optical filter can be mounted on such an optical filter mounting portion 30 ', and it is not necessary to produce a new optical filter for the present application, which makes it possible to reduce costs. Become.

  In the second embodiment, it is assumed that the optical filter mounting portion 30 'is attached to the subject side of the photographing lens system of the digital camera. For this reason, the optical filter mounting portion 30 ′ is located farther from the image sensor than the photographic lens system. However, the present application is not limited to this, and the positional relationship between the optical filter mounting portion 30 ′ and the photographing lens system is opposite to that in FIG. 7, that is, the optical relationship between the photographing lens system and the image sensor. You may arrange | position filter mounting part 30 '.

  The first and second embodiments have been described above. However, these embodiments are merely examples, and the present application is not limited to these embodiments. Any configuration that can maintain the installation angle of the optical filter with respect to the subject (the angle formed by the absolute reference axis l and the reference axis n of the optical filter) without being affected by the attitude of the imaging apparatus is applicable. It is possible to solve this problem.

1 Digital camera (imaging device, imaging device body)
20 Main control unit (optical filter angle adjustment unit)
21 Optical System 22 Optical System Drive Unit 23 Image Sensor 28 Acceleration Sensor (Attitude Detection Unit)
30 Optical filter 302, 302 'Gear part (angle setting part)
31, 31 ′ Optical filter rotation drive unit 32 Optical filter rotation angle detection unit (optical filter angle adjustment unit)
l Absolute reference axis (first axis)
m, m0, m1, m2 Reference axes (digital camera)
n, n0, n1, n2, n3 Reference axis (second axis: optical filter)

JP 2006-166006 A

Claims (11)

An imaging device body;
An image sensor that receives subject light incident via an optical system and outputs it as an image signal by converting it into an electrical signal;
An optical filter that is provided in the optical system and rotates around the optical axis of the optical system;
An optical filter rotation drive unit for rotating the optical filter;
A posture detection unit for detecting posture information of the imaging device body;
Based on the posture information of the imaging apparatus main body, the optical filter rotation driving unit is controlled to rotate the optical filter, and the first extending in the vertical direction through the optical axis in a plane orthogonal to the optical axis. And an optical filter angle adjusting unit that maintains a constant angle between a predetermined position of the optical filter and a second axis passing through the optical axis in a plane orthogonal to the optical axis. An imaging apparatus characterized by the above. An imaging device body;
An image sensor that receives subject light incident via an optical system and outputs it as an image signal by converting it into an electrical signal;
An optical filter that is provided in the optical system and rotates around the optical axis of the optical system;
An optical filter rotation drive unit for rotating the optical filter;
An attitude detection unit for detecting attitude information of the imaging apparatus main body,
In the plane orthogonal to the optical axis, the posture detection unit detects that the tilt angle of the imaging device main body has changed from the first angle to the second angle,
A first axis extending vertically through the optical axis in a plane orthogonal to the optical axis, and a second axis passing through a predetermined position of the optical filter and the optical axis in a plane orthogonal to the optical axis. An image pickup apparatus, wherein the optical filter is controlled by the optical filter rotation drive unit so that the angle formed by the optical filter maintains a tilt angle of the image pickup apparatus main body at a first angle. An imaging device body;
An image sensor that receives subject light incident via an optical system and converts it into an electrical signal to output it as an image signal; and
An optical filter that is provided in the optical system and changes the subject light passing therethrough by rotating about the optical axis of the optical system as a central axis;
An optical filter rotation drive unit for rotating the optical filter about the optical axis of the optical system as a central axis;
A posture detection unit for detecting posture information of the imaging device body;
A fixed axis that is orthogonal to the optical axis and does not change with a change in posture of the imaging device body and rotation of the optical filter is defined as a reference axis l.
An axis that extends perpendicular to the optical axis and that rotates with the optical axis as a central axis in accordance with a change in posture of the imaging apparatus body is a reference axis m of the imaging apparatus body,
An axis extending orthogonally to the optical axis, the axis rotating around the optical axis as the optical filter rotates is defined as a reference axis n of the optical filter;
When the posture detection unit detects a change in the posture of the imaging device body, the reference axis l acquired based on the posture information after the posture change and the reference axis m of the imaging device body are formed. Calculating the difference between the angle and the angle formed by the reference axis l acquired based on the posture information before the posture change and the reference axis m of the imaging device body;
An optical filter angle adjusting unit configured to rotate the optical filter by the optical filter rotation driving unit based on the difference and maintain a constant angle formed by the reference axis l and the reference axis n of the optical filter; An image pickup apparatus comprising: The optical filter angle adjusting unit is
An optical filter rotation angle detector that detects an angle formed by the reference axis m of the imaging apparatus body and the reference axis n of the optical filter;
When the angle formed by the reference axis m of the imaging apparatus body and the reference axis n of the optical filter is changed, the angle and the angle formed by the reference axis l and the reference axis m of the imaging apparatus body are changed. The imaging apparatus according to claim 3, further comprising: an angle setting unit that calculates an angle formed by the reference axis 1 and the reference axis n of the optical filter based on the angle. When the posture of the imaging device main body is changed,
An angle formed by the reference axis l and the reference axis m acquired based on the attitude information before the attitude change of the imaging apparatus main body detected by the attitude detection unit is θ2,
When the angle formed by the reference axis l and the reference axis m acquired based on the attitude information after the attitude change of the imaging device body detected by the attitude detection unit is θ2 ′,
The optical filter angle setting unit calculates the difference between the angle θ2 and the angle θ2 ′ as follows: Δθ = θ2′−θ2
Calculated by
The imaging apparatus according to claim 3, wherein the optical filter rotation driving unit rotates the optical filter at an angle of Δθ. An angle formed by the reference axis m of the imaging device main body detected by the optical filter rotation angle detection unit and the reference axis n of the optical filter is θ3,
When the angle formed by the reference axis l and the reference axis m acquired based on the attitude information of the imaging apparatus main body detected by the attitude detection unit is θ2,
The optical filter angle setting unit determines an angle θ1 formed by the reference axis l and the reference axis n of the optical filter as follows: θ1 = θ2 + θ3
The imaging device according to claim 4, wherein the imaging device is calculated by:   The imaging device according to claim 1, wherein the optical filter is a polarization filter. An imaging device main body, an imaging device that receives subject light incident through an optical system, and an optical device that is provided in the optical system and changes the subject light passing through the optical system by rotating about the optical axis of the optical system A filter, an optical filter rotation drive unit that rotates the optical filter around the optical axis, an attitude detection unit that detects the attitude of the imaging device body, and an optical filter angle adjustment unit that adjusts the rotation angle of the optical filter And an imaging method of the imaging device provided,
A fixed axis that is orthogonal to the optical axis and does not change with a change in posture of the imaging device body and rotation of the optical filter is defined as a reference axis l.
An axis that extends perpendicular to the optical axis and that rotates with the optical axis as a central axis in accordance with a change in posture of the imaging apparatus body is a reference axis m of the imaging apparatus body,
An axis extending orthogonally to the optical axis, the axis rotating around the optical axis as the optical filter rotates is defined as a reference axis n of the optical filter;
When the posture detection unit detects a change in the posture of the imaging device body,
The optical filter angle adjustment unit uses the angle formed by the reference axis l acquired based on the posture information after the posture change and the reference axis m of the imaging apparatus body, and the posture information before the posture change. Calculating an angle difference between the reference axis l acquired based on the reference axis m of the imaging apparatus main body;
The optical filter rotation driving unit rotating the optical filter based on the difference, and maintaining a constant angle formed by the reference axis l and the reference axis n of the optical filter; A characteristic imaging method. The optical filter angle adjustment unit has an optical filter rotation angle detection unit and an angle setting unit,
The optical filter rotation angle detection unit detecting an angle formed by the reference axis m of the imaging apparatus body and the reference axis n of the optical filter;
The angle setting unit determines whether the angle formed by the reference axis m of the imaging device body and the reference axis n of the optical filter has been changed;
When the angle is changed, the angle formed by the reference axis l and the reference axis n of the optical filter is determined based on the angle and the angle formed by the reference axis l and the reference axis m of the imaging apparatus body. The imaging method according to claim 8, further comprising a step of calculating. When the posture of the imaging device main body is changed,
An angle formed by the reference axis l and the reference axis m acquired based on the attitude information before the attitude change of the imaging apparatus main body detected by the attitude detection unit is θ2,
When the angle formed by the reference axis l and the reference axis m acquired based on the attitude information after the attitude change of the imaging device body detected by the attitude detection unit is θ2 ′,
The optical filter angle setting unit calculates the difference between the angle θ2 and the angle θ2 ′ as follows: Δθ = θ2′−θ2
Calculated by
The imaging method according to claim 8 or 9, wherein the optical filter rotation driving unit rotates the optical filter at an angle of Δθ. An angle formed by the reference axis m of the imaging device main body detected by the optical filter rotation angle detection unit and the reference axis n of the optical filter is θ3,
When the angle formed by the reference axis l and the reference axis m acquired based on the attitude information of the imaging apparatus main body detected by the attitude detection unit is θ2,
The optical filter angle setting unit determines an angle θ1 formed by the reference axis l and the reference axis n of the optical filter as follows: θ1 = θ2 + θ3
The imaging method according to claim 8, which is calculated by: