Lens device and imaging system

Abstract

To provide a lens device that can acquire an appropriate three-dimensional photographic image reflecting a user's photographic intention.SOLUTION: A lens device (200) is removably mounted on an imaging apparatus (110), and has: a first optical system (201L); a second optical system (201R) that is arranged in parallel with the first optical system; and a lens mount (202) that can be attached to the imaging apparatus (110). The first optical system forms a first image (ICL) at a first focal length, and the second optical system forms a second image (ICR) corresponding to the first image at a second focal length shorter than the first focal length.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a lens device and an imaging system.

Background Art

[0002] Conventionally, a lens device (interchangeable lens for stereoscopic photography) configured by arranging two optical systems in parallel has been known. An image formed by one optical system is recorded as a moving image or a still image for the right eye, and an image formed by the other optical system is recorded as a moving image or a still image for the left eye. At the time of reproduction, by viewing using a known 3D display or VR goggles, etc., an image for the right eye is projected onto the user's right eye, and an image for the left eye is projected onto the left eye. At this time, due to the baseline length of the two optical systems, images with a parallax are projected onto the right and left eyes, so the user can obtain a sense of stereoscopy.

[0003] Here, in order to appropriately perform stereoscopic viewing of the two images obtained from the two optical systems, it is necessary to be photographed by two optical systems having the same focal length and parallel optical axes. However, when manufacturing a lens device, it is difficult and costly to adjust the focal lengths of the two optical systems to be the same and the optical axes to be parallel with high precision.

[0004] Therefore, after performing stereoscopic photography using two optical systems, by performing image correction processing on the obtained images, the focal lengths of the right-eye image and the left-eye image are adjusted, and the optical axis deviation is corrected to obtain two images having appropriate parallax that can be stereoscopically viewed. A technique is known.

[0005] Patent Document 1 discloses an imaging device capable of appropriately correcting an image in a later process by storing in advance information on the optical axis center position and the cutout size of each imaging optical system for cutting out an image from a photographed image at each zoom position and recording it together with the photographed image.

Prior Art Documents

Patent Documents

[0006] Patent Document 1 Japanese Patent No. 5166650 Summary of the Invention Problems to be Solved by the Invention

[0007] In the imaging device disclosed in Patent Document 1, since an image is corrected using manufacturing error information stored in advance at the time of manufacture, when the combination of the imaging device and the interchangeable lens is not always the same, such as in the case of an interchangeable lens for stereoscopic photography, there is a possibility that the image cannot be corrected correctly. Further, when the user performs an operation to change the focal length, if conditions such as the direction of change of the focal length (movement from the wide-angle side to the telephoto side, or movement from the telephoto side to the wide-angle side) are different from the inspection conditions of the manufacturing process, actually, there is a possibility that an error different from the manufacturing error stored in advance may occur.

[0008] In addition, the composition and shooting range of the subject intentionally determined and shot by the user are changed based on the manufacturing error information stored in advance in the post-shot image correction process. As a result, the obtained stereoscopic photographed image may have the user's shooting intention impaired.

[0009] Therefore, an object of the present invention is to provide a lens device capable of acquiring an appropriate stereoscopic photographed image that reflects the shooting intention of the user. Means for Solving the Problems

[0010] A lens device according to one aspect of the present invention is a lens device detachable from an imaging device, having a first optical system, a second optical system arranged in parallel with the first optical system, and a lens mount attachable to the imaging device. The first optical system forms a first image at a first focal length, and the second optical system forms a second image corresponding to the first image at a second focal length shorter than the first focal length.

[0011] Other objects and features of the present invention will be described in the following embodiments. Advantages of the Invention

[0012] According to the present invention, it is possible to provide a lens device capable of acquiring an appropriate stereoscopic captured image reflecting the user's intention to capture an image.

Brief Description of the Drawings

[0013]

Figure 1

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Modes for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0015] (First Embodiment) First, the first embodiment of the present invention will be described. The interchangeable lens of this embodiment has two optical systems (a first optical system and a second optical system) arranged in parallel with each other, and is configured such that two image circles are formed in parallel on one imaging device. The two optical systems are arranged horizontally at a predetermined distance (baseline length). When viewed from the image side, the image formed by the left optical system (the first optical system) is recorded as a moving image or a still image for the left eye, and the image formed by the right optical system (the second optical system) is recorded as a moving image or a still image for the right eye. When playing back the moving image or the still image (image or video), by viewing it using a known 3D display or a so-called VR goggles, etc., an image for the right eye is projected onto the user's right eye, and an image for the left eye is projected onto the left eye. At this time, due to the baseline length of the interchangeable lens, images with a parallax are projected onto the right eye and the left eye, so the user can obtain a stereoscopic effect. Thus, the interchangeable lens of this embodiment is an interchangeable lens for stereoscopic photography capable of forming two images with a parallax by the first optical system and the second optical system.

[0016] Referring to FIG. 1, the imaging system 100 in this embodiment will be described. FIG. 1 is a configuration diagram of the imaging system 100. The imaging system 100 includes a camera body (imaging device) 110 and an interchangeable lens (lens device) 200 detachably attached to the camera body 110. In the following description, an R is added to the end of the reference numeral for the description of the right-eye optical system, and an L is added to the end of the reference numeral for the description of the left-eye optical system. For descriptions common to both the right-eye optical system and the left-eye optical system, neither R nor L is added to the end of the reference numeral.

[0017] The interchangeable lens 200 has a left-eye optical system (the first optical system) 201L and a right-eye optical system (the second optical system) 201R. For example, when the interchangeable lens 200 is attached to the camera body 110, the left-eye optical system 201L and the right-eye optical system 201R are arranged in parallel along the long side direction of the imaging device 111. The left-eye optical system 201L is located on the left side when viewed from the back of the camera body 110.

[0018] The left optical system 201L and the right optical system 201R each have, in order from the subject side (object side) to the image side, a first optical axis OA1, a second optical axis OA2 that is substantially orthogonal to the first optical axis OA1, and a third optical axis OA3 that is parallel to the first optical axis OA1. Along each optical axis, a first lens (first lens group) 211 is disposed on the first optical axis OA1, a second lens (second lens group) 221 is disposed on the second optical axis OA2, and a third lens (third lens group) 231 is disposed on the third optical axis OA3. Each optical system is a bending optical system having a first prism (first reflecting surface) 220 that bends the light beam of the first optical axis OA1 and guides it to the second optical axis OA2, and a second prism (second reflecting surface) 230 that bends the light beam of the second optical axis OA2 and guides it to the third optical axis OA3.

[0019] The second optical axis OA2 is an optical axis that is reflected by the first prism 220 and bent from the first optical axis OA1. The third optical axis OA3 is the optical axis closest to the image plane that is reflected by the second prism 230 and bent from the second optical axis OA2. The first optical axis OA1 of each optical system is outside the mount diameter of the lens mount 202. The third optical axis OA3 of each optical system is inside the mount diameter. The focal length of each optical system is variable, and when the focal length of one of the two optical systems is changed, the focal length of the other is changed in the same direction. That is, the focal length of one of the two optical systems changes in conjunction with the change in the focal length of the other.

[0020] Next, with reference to FIG. 2, when observing the first lens 211 from the side of the imaging element 111 along the first optical axis OA1, the positional relationship between the positions of the optical axes of the interchangeable lens 200 and the mount, and the image circle on the imaging element 111 on the camera body 110 side will be described. FIG. 2 is an arrangement diagram of the optical axes of the interchangeable lens 200 and the image circle on the imaging element 111.

[0021] As shown in FIG. 2, on the imaging device 111, an image circle ICL as a first image (first captured image) formed by the left-eye optical system 201L and an image circle ICR as a second image (second captured image) formed by the right-eye optical system 201R are arranged in parallel. The image circle ICL is the left-eye image circle, and the image circle ICR is the right-eye image circle. It is preferable to set the size of each image circle and the separation distance between the image circles so that the two image circles do not overlap as much as possible. For example, considering a region obtained by dividing the light-receiving range of the imaging device 111 into left and right halves at the center, it is preferable to set the center of the image circle ICR to be located approximately at the center of the right region of the light-receiving range, and the center of the image circle ICL to be located approximately at the center of the left region of the light-receiving range.

[0022] The distance between the first optical axis OA1R of the right-eye optical system 201R and the first optical axis OA1L of the left-eye optical system 201L is referred to as the baseline length L1. The average distance between the two eyes of a human is said to be about 60 to 65 mm, and there is a desire to perform imaging with a baseline length L1 that is the same as or greater than this in order to obtain a natural stereoscopic effect similar to that of a human eye.

[0023] According to the configuration of the present embodiment, with respect to the distance L2 between the third optical axis OA3L and the third optical axis OA3R that needs to fit within the inner diameter of the camera mount 122, the baseline length L1 becomes longer than the optical path division length of the second optical axis OA2. Therefore, it is possible to make the baseline length L1 larger than that, regardless of the fitting diameter ΦD between the camera mount 122 and the lens mount 202.

[0024] In the present embodiment, the baseline length L1 is configured to be approximately 60 mm, and the first optical axis OA1 is outside the fitting diameter ΦD of the camera mount 122. However, this is merely an example, and the present embodiment is not limited thereto.

[0025] The interchangeable lens 200 has, on the left and right sides respectively, zoom lens driving means (zoom lens driving motors) 207L and 207R for driving the first lens 211. When the zoom lens driving means 207L and 207R are driven by an operation of the camera body 110 by the user, the first lens 211 moves along the first optical axis OA1. As a result, each optical system can change the focal length in the same direction (the focal length of each optical system is variable).

[0026] The interchangeable lens 200 also has, on the left and right sides respectively, focus lens driving means (focus lens driving motors) 208L and 208R for driving the third lens 231. When the focus lens driving means 208L and 208R are driven by an operation of the camera body 110 by the user or by automatic control by the camera body 110, the third lens 231 moves along the third optical axis OA3. As a result, each optical system can focus on the subject.

[0027] The light beams that have passed through the left-eye optical system 201L and the right-eye optical system 201R of the interchangeable lens 200 are simultaneously imaged as an image circle ICL and an image circle ICR on a single image sensor 111 of the camera body 110. As a result, two subject images having parallax are acquired as single image data. The interchangeable lens 200 includes a lens control unit 203, communicates with a system control unit 117 of the camera body 110, and cooperates with the camera body 110 to control the imaging system 100, such as performing the above-described change in focal length and focus adjustment. The interchangeable lens 200 also includes a storage unit 204, which stores lens information such as lens individual information 205, lens manufacturing error information 206, and focal length correction information 209. The lens control unit 203 transmits lens information such as lens individual information 205, lens manufacturing error information 206, and focal length correction information 209 to the system control unit 117 in response to a request from the system control unit 117.

[0028] The camera body 110 includes an imaging device 111, an A / D conversion unit 112, an image processing unit 113, a display unit 114, an operation unit 115, a recording unit 116, a system control unit 117, a memory unit 118, and a camera mount 122. When the lens mount 202 of the interchangeable lens 200 is attached to the camera mount 122 of the camera body 110, the system control unit 117 of the camera body 110 and the lens control unit 203 of the interchangeable lens 200 are electrically connected.

[0029] The image of the subject is simultaneously formed on the imaging device 111 such that the image circle ICR formed via the right-eye optical system 201R and the image circle ICL formed via the left-eye optical system 201L are arranged side by side. The imaging device 111 converts the formed image of the subject (optical signal) into an analog electrical signal. The A / D conversion unit 112 converts the analog electrical signal output from the imaging device 111 into a digital electrical signal (image signal). The image processing unit 113 performs various image processes on the digital electrical signal (image signal) output from the A / D conversion unit 112, and outputs two subject images having parallax as single image data. Note that the A / D conversion unit 112 and the image processing unit 113 may be built in the imaging device 111.

[0030] The display unit 114 displays various types of information. The display unit 114 is realized, for example, by using an electronic viewfinder or a liquid crystal panel. The operation unit 115 functions as a user interface for the user to give instructions to the camera body 110. When the display unit 114 has a touch panel, the touch panel is one of the operation units 115.

[0031] The recording unit 116 writes the image data processed by the image processing unit 113 and the like to a storage medium such as a flash memory or a hard disk. The storage unit 118 stores information such as camera individual information 119 and camera manufacturing error information 120. The camera individual information 119 is, for example, the model information of the camera body 110, the pixel number information of the imaging device 111, and the physical size information of the imaging device 111. The camera manufacturing error information 120 is, for example, the inclination information of the imaging device 111 with respect to the camera mount 122 and the individual difference information such as the color or luminance of the imaging device 111. The camera individual information 119 and the camera manufacturing error information 120 are written to the storage unit 118 in the manufacturing process of the camera body 110.

[0032] When performing shooting, the system control unit 117 controls the camera body 110 based on the individual identification information of the camera body 110 (camera individual information 119 and camera manufacturing error information 120) and the lens information of the interchangeable lens 200 acquired from the lens control unit 203. The storage unit 118 stores programs. The storage unit 118 is realized, for example, by using a volatile memory, a non-volatile memory, and a hard disk. The system control unit 117 comprehensively controls the entire imaging system 100. The system control unit 117 is realized, for example, by using a CPU.

[0033] Next, with reference to FIG. 3, the operation (control method) of the imaging system 100 will be described. FIG. 3 is a flowchart showing the operation of the imaging system 100. In the imaging system 100 of the present embodiment, since the camera body 110 and the interchangeable lens 200 are configured separately, as a pre-step of shooting, the user attaches the camera body 110 and the interchangeable lens 200. By electrically and mechanically attaching and fixing the camera body 110 and the interchangeable lens 200 via the lens mount 202 and the camera mount 122, the lens control unit 203 and the system control unit 117 are in a state where they can communicate bidirectionally.

[0034] First, in step S100, the interchangeable lens 200 is attached to the camera body 110 by the user, and the power of the camera body 110 is turned on. Subsequently, in step S101, the system control unit 117 communicates with the lens control unit 203 and acquires the lens individual information 205, the lens manufacturing error information 206, and the focal length correction information 209 stored in the storage unit 204. The lens individual information 205 includes the optical design information of the interchangeable lens 200. For example, in the present embodiment, the baseline length L1 is configured to be a distance of 60 mm, which is close to the human eye width, so that an appropriate parallax can be obtained during VR viewing, and the lens individual information 205 includes information regarding the baseline length L1, such as the value of the baseline length L1. Thereby, the camera body 110 recognizes that the attached interchangeable lens is the interchangeable lens 200 for stereoscopic photography.

[0035] The lens manufacturing error information 206 includes the manufacturing error information for each lens individual acquired in the manufacturing process, that is, the optical axis deviation information and the focal length deviation information of the right optical system 201R with respect to the left optical system 201L. Due to various assembly errors and part tolerances in the manufacturing process, the optical axes of the two optical systems forming the two images are not ideally parallel and are considered to have an optical axis deviation. Also, since the distance between the lens elements also has a manufacturing error, a focal length deviation of the two optical systems forming the two images may occur.

[0036] However, these pieces of information are the information acquired under certain inspection conditions during manufacturing. On the other hand, when the focal length is changed by the user, there are various conditions, such as the temperature conditions and the direction of change of the focal length at the time of the change of the focal length. Also, when the interchangeable lens is attached to a camera body of a different individual, the manufacturing tilt error and position deviation of the image sensor 111 with respect to the camera mount 122 are different for each individual. Also, each time the camera body 110 and the interchangeable lens 200 are attached and detached, different mounting errors occur between the camera mount 122 and the lens mount 202 each time.

[0037] Therefore, each time these operations are performed, the amount of focus shift, the amount of optical axis shift, and the optical axis shift direction of the two finally obtained images can change each time. Therefore, the lens manufacturing error information 206 obtained during the manufacture of the interchangeable lens 200 is treated as reference information. The lens manufacturing error information 206 is used when performing correction so that the left and right images can be appropriately stereoscopically viewed in the process of generating VR images, which will be described later.

[0038] Subsequently, in step S102, the system control unit 117 reads out the camera individual information and the camera manufacturing error information from the storage unit 118.

[0039] Subsequently, in step S103, the lens control unit 203 reads out the focal length correction information 209 stored in the storage unit 204. The focal length correction information 209 includes information on the focal length (focal length L, first focal length) of the left optical system 201L and information on the corresponding focal length (focal length R, second focal length) of the right optical system 201R. Note that the magnitude relationship between the focal length L and the focal length R can be interchanged, and this embodiment is applicable to any case.

[0040] The lens control unit 203 drives the zoom lens driving means 207L and 207R based on the focal length correction information 209 (information on the focal lengths L and R) to adjust the focal lengths L and R of the left and right optical systems. Note that the details of the focal length correction information 209 will be described later. At this time, the system control unit 117 calculates the focus position of the subject image using the information of the image circle ICL. Then, the system control unit 117 sends a drive instruction to the lens control unit 203 to the focus lens driving means 208L and 208R. Thereby, the lens control unit 203 performs focus adjustment of the left and right optical systems.

[0041] That is, the left-eye optical system 201L forms a first image (image circle ICL) at the first focal length, and the right-eye optical system 201R forms a second image (image circle ICR) corresponding to the first image at a second focal length shorter than the first focal length. For example, the right-eye optical system 201R forms the second image simultaneously (at the same timing) with the formation of the first image by the left-eye optical system 201L. Note that the magnitude relationship between the first focal length and the second focal length may be reversed (the second focal length may be longer than the first focal length).

[0042] Subsequently, in step S104, the system control unit 117 causes the display unit 114 to display the live view image obtained by the imaging element 111. For example, the live view image is an image corresponding to a portion of the image circle ICL obtained by the left-eye optical system 201L among the image data continuously output from the image processing unit 113 in time series. That is, the image circle ICL is displayed on the display unit 114 during shooting preparation (and during shooting).

[0043] Subsequently, in step S105, when the user refers to the live view image through the monitor or viewfinder which is the display unit 114, a state is reached where the composition of the subject, the focus position, or the focal length of the interchangeable lens 200 can be determined. Thereby, the shooting preparation is completed.

[0044] Subsequently, in step S106, the system control unit 117 determines whether or not a change instruction for the focal length of the interchangeable lens 200 has been input to the operation unit 115 by the user (whether or not a change operation for the focal length has been performed by the user). If it is determined that a change operation for the focal length has been performed, the process proceeds to step S107. On the other hand, if it is determined that no change operation for the focal length has been performed, the process proceeds to step S111.

[0045] In step S107, the system control unit 117 sends an instruction to change the focal length to the lens control unit 203. Subsequently, in step S108, the lens control unit 203 that has received the instruction to change the focal length checks the focal length correction information 209. Subsequently, in step S109, the lens control unit 203 drives the zoom lens driving means 207L based on the change instruction, moves the first lens 211L, and changes the focal length L (the first focal length) (lens driving). Further, the lens control unit 203 drives the zoom lens driving means 207R so that the focal length becomes the focal length R (the second focal length) corresponding to the changed focal length L, and adjusts the focal length R (focal length adjustment).

[0046] At this time, the system control unit 117 calculates the focus position of the subject image using the information of the image circle ICL. Further, the system control unit 117 sends a driving instruction to the focus lens driving means 208L and 208R to the lens control unit 203. Then, the lens control unit 203 performs focus adjustment of the left and right optical systems based on the driving instruction.

[0047] Subsequently, in step S110, the system control unit 117 acquires the values of the focal lengths L and R and the notification of completion of the change in the focal length from the lens control unit 203. Then, it returns to step S105. Thereby, the system control unit 117 completes the shooting preparation.

[0048] In step S111, when a shooting start instruction is input from the operation unit 115 of the camera body 110 by the user, the system control unit 117 starts shooting, and the image data is recorded in the recording unit 116. The image data corresponds to the image circles ICL and ICR, and is single image data in which two subject images having parallax are arranged side by side through the A / D conversion unit 112 and the image processing unit 113. The lens individual information 205, the lens manufacturing error information 206, the camera individual information 119, the camera manufacturing error information 120, and the focal length correction information 209 acquired in steps S101 and S102, and the values of the focal lengths L and R are recorded as attached information in the image data.

[0049] In the case of video shooting, shooting continues continuously after step S111, and during that time, the user may perform an operation to change the focal length. Also in that case, steps S106 to S110 are repeated while shooting continues. In the case of a video, in step S111, additional information corresponding to the image data arranged in time series is recorded. The additional information includes, for example, lens individual information 205, lens manufacturing error information 206, camera individual information 119, camera manufacturing error information 120, focal length correction information 209, the values of the focal lengths L and R, and information on the completion notification of the focal length change.

[0050] Here, referring to FIGS. 4 to 7, a case will be described where the lens control unit 203 does not refer to the focal length correction information 209 and controls the left optical system 201L and the right optical system 201R to have the same focal length. Also in this case, the influence of the optical axis deviation, the focal length deviation, and various errors of the image circles ICL and ICR projected onto the imaging element 111 on the stereoscopic image will be described.

[0051] FIGS. 4 to 6 are views of the image circles ICL and ICR projected onto the imaging element 111 as seen from the back of the camera body 110, and the image data recorded in the recording unit 116 in step S111 of FIG. 3 is recorded in this state. Here, originally, the image projected onto the imaging element 111 should be an image that is inverted upside down and left to right, but for simplicity of explanation, the explanatory diagram shows an image that is not inverted upside down and left to right. Also, for easier visual understanding, center lines are drawn on both image circles, but they do not actually exist.

[0052] FIG. 4 is a view showing an ideal state of the image circles ICL and ICR on the imaging element 111. That is, FIG. 4 shows a design-ideal state where the left optical system 201L and the right optical system 201R have no optical axis deviation or focal length deviation, and the camera body 110 is also in a design-ideal state. In FIG. 4, the position of the optical axis center of the image circle ICL with respect to the imaging element 111 (ICL center position 330L) and the position of the optical axis center of the image circle ICR (ICR center position 330R) are at the designed positions.

[0053] Since there is no optical axis deviation between the left optical system 201L and the right optical system 201R, the ICL optical axis center 320L and the ICR optical axis center 320R coincide with each other. The focal length L of the image circle ICL and the focal length R of the image circle ICR also coincide with each other. In this state, the user does not need to perform image processing (image correction processing) such as optical axis deviation correction or focal length deviation correction on the obtained image, and can appropriately perform stereoscopic viewing by using existing VR viewing devices.

[0054] FIG. 5 is a diagram showing an example of the actual state of the image circles ICL and ICR on the imaging element 111. That is, FIG. 5 shows an example of a state that is most affected by manufacturing errors, mounting errors of the camera body 110 and the interchangeable lens 200, errors due to play during the focal length change operation, and the like. For simplicity of explanation, it will be described assuming that only the image circle ICR is affected.

[0055] In the state of FIG. 5, the ICR center position 330R with respect to the imaging element 111 is deviated from the design position and is located below. Further, due to the influence of the optical axis deviation between the left optical system 201L and the right optical system 201R, the ICR optical axis center 320R is deviated downward to the right with respect to the position corresponding to the optical axis center of the image circle ICL, 321.

[0056] Even if the first lenses 211L and 211R are driven so that the left optical system 201L and the right optical system 201R have the same focal length, due to various errors, actually the focal length R of the image circle ICR is shifted toward the tele side with respect to the focal length L of the image circle ICL. That is, relatively, the size of the subject (the same subject) in the image circle ICR is larger than the subject (the same subject) in the image circle ICL. Therefore, in the state of FIG. 5, the user cannot perform stereoscopic viewing as it is, and it is necessary to perform image processing (image correction processing) on the image data written in the recording unit 116 after shooting using an information processing device such as a computer.

[0057] Referring to FIG. 6, image correction processing using a predetermined application or program on a computer will be described. FIG. 6 is an explanatory diagram of image correction processing for proper stereoscopic vision.

[0058] The predetermined application or program first detects feature points on each of the images of the image circles ICL and ICR from the captured image data. Examples of the feature points are the edges of the building and the patterns on the ground in FIG. 6. Referring to the detected feature point information, together with the lens individual information 205, lens manufacturing error information 206, camera individual information 119, camera manufacturing error information 120, which are the attached information of the image, and the focal lengths L and R. Then, using a predetermined algorithm, the magnification deviation amount, optical axis deviation amount, and optical axis deviation direction of the image circles ICL and ICR are calculated. Here, the magnification deviation amount is the magnification when either one is enlarged so that the focal lengths of the actually captured image circles ICL and ICR match. For example, as shown in FIG. 6, consider the case where the focal length of the image circle ICR is longer (the angle of view is smaller) than that of the image circle ICL. In this case, it is the magnification when the image circle ICL (the image with a wider angle of view and the subject relatively smaller) is enlarged to match the focal length R of the actual image circle ICR.

[0059] As shown in FIG. 6, since the focal length of the image circle ICR is shifted toward the telephoto side compared to the focal length of the image circle ICL, the shooting range is narrower than that of the image circle ICL. Therefore, in order to obtain two images with the same focal length for proper stereoscopic vision, it is necessary to cut out a range corresponding to the focal length R of the image circle ICR from the image circle ICL.

[0060] The corrected ICL, which is the region drawn by the dashed line in FIG. 6, is the region corresponding to the focal length R of the image circle ICR on the image circle ICL. The corrected ICL has a region with a diameter obtained by multiplying the reciprocal of the calculated magnification deviation amount by the diameter of the image circle ICL.

[0061] In addition, since the optical axes are also misaligned, when cutting out in the area of the corrected ICL, it is necessary to cut out in an area centered on the position (equivalent position of the ICR optical axis center) 322 where the amount and direction of the optical axis misalignment are corrected. As a result, a part of the corrected ICL may protrude from the original image circle ICL, and there is a possibility that a part of the image of the corrected ICL will be missing.

[0062] After that, an image correction process is performed in which the corrected ICL is enlarged by the amount of magnification misalignment and the center position of the corrected ICL and the ICR center position 330R are moved so as to match the design values, and the final image data is output on the computer as shown in FIG. 7. FIG. 7 is a diagram showing the image data after performing the image correction process for appropriate stereoscopic viewing. By performing such an image correction process, as shown in FIG. 7, single image data with two subject images having parallax that enables appropriate stereoscopic viewing is obtained.

[0063] However, while the user takes a picture while checking the live view image, that is, the image of the image circle ICL, in the obtained image, the area that should have been shown in the image of the image circle ICL in FIG. 5 is missing. In addition, since a part of the image of the corrected ICL in the obtained image is missing as described above, that part cannot be viewed stereoscopically. Therefore, it is difficult to say that image data that fully reflects the user's shooting intention has been obtained. Therefore, in the present embodiment, the zoom lens driving means 207L and 207R are controlled with reference to the focal length correction information 209 including information on the focal length R of the right optical system 201R corresponding to the focal length L of the left optical system 201L.

[0064] Next, with reference to FIGS. 8(a) and 8(b), the focal length correction information 209 will be described in detail. FIG. 8 is an explanatory diagram of the image correction process, and is an explanatory diagram of the relationship between the focal length L of the left optical system 201L and the corresponding focal length R of the right optical system 201R stored as the focal length correction information 209. FIG. 8(a) shows the image circle ICL in FIG. 5, and FIG. 8(b) shows the image circle ICR in FIG. 5.

[0065] In FIG. 8(b), the maximum optical axis deviation amount α is the maximum distance on the imaging device 111 between the ICR optical axis center 320R and the position corresponding to the ICL optical axis center 323R, which is obtained when considering various conditions such as component tolerances, assembly errors, mounting errors, and temperature changes in the design. This can be obtained by utilizing simulation techniques and the like.

[0066] The maximum magnification deviation amount β is the maximum designed value of the magnification when either one of the focal lengths of the image circles ICL and ICR is enlarged so that they match each other. This can be obtained by utilizing simulation techniques and the like. Here, the user is taking a picture while referring to the live view image, which is an image of the image circle ICL. Therefore, in order to obtain two appropriate images enabling stereoscopic viewing that reflects the user's shooting intention, it is considered to cut out a region corresponding to the focal length L of the image circle ICL from the image circle ICR.

[0067] The optical axis of the image circle ICR is deviated from that of the image circle ICL. Therefore, a region 301 (dashed line) with the same diameter as the image circle ICR is set with the position corresponding to the ICL optical axis center 323R shifted by the maximum optical axis deviation amount α from the ICR optical axis center 320R as the center. At this time, let the radius of the region 301 be r1.

[0068] The focal length of the image circle ICR is longer (the angle of view is narrower) than that of the image circle ICL. Therefore, in order to cut out at the focal length corresponding to the image circle ICL, the region 301 is enlarged by the maximum magnification deviation amount β to obtain a region 302 (dash-dotted line). At this time, the radius of the region 302 is βr1.

[0069] The direction of the optical axis deviation between the image circle ICR and the image circle ICL can be considered in all directions with the ICR optical axis center 320R as the center. Therefore, the range that may be cut out in the post-shooting image correction process is the region 303 that circumscribes the region 302 with the ICR optical axis center 320R as the center. The radius r2 of the region 303 is expressed by the following formula (1).

[0070] r2 = α + βr1 …(1) Therefore, if the image circle ICR corresponding to the focal length corresponding to the region 303 is acquired in advance, the image region corresponding to the image circle ICL can be cut out from the image circle ICR without lacking the region of the image circle ICL under various conditions. The focal length correction information 209 is information recorded in association with each focal length L with the focal length corresponding to the region 303 at this time as the focal length R.

[0071] FIG. 9 shows an example of image data when the image circle ICR is acquired at the focal length corresponding to the region 303. The state of FIG. 9 is a state where the focal length L is at the wide end (wide-angle end) of the interchangeable lens 200.

[0072] As described above, the focal length of the image circle ICR is shorter and the angle of view is wider than that of the image circle ICL. For this reason, even when the corrected ICR (third image, third captured image), which is the region corresponding to the focal length L of the image circle ICL, is cut out from the image circle ICR with the position 321 corresponding to the optical axis center of the ICL as the center, the image of the corrected ICR is not cut off.

[0073] That is, the focal length R of the right-eye optical system 201R is shorter than the focal length L of the left-eye optical system 201L by a predetermined amount. Here, the predetermined amount is an amount that enables the third image (corrected ICR) formed by the right-eye optical system 201R at the focal length L to be cut out from the image circle ICR so as to correct the deviation of the optical axis of the right-eye optical system 201R with respect to the left-eye optical system 201L.

[0074] Thereafter, when an image correction process is performed in which the corrected ICR is enlarged by the magnification deviation amount and the center position of the corrected ICR and the ICL center position 330L are moved so as to match the design values, the final image data is output in the form shown in FIG. 4.

[0075] The image circle ICL that the user referred to when taking a picture as a live view image remains the same as the original image that the user was originally looking at. Therefore, by combining it with the corrected ICR, two images with the same focal length that can be appropriately stereoscopically viewed and reflect the user's shooting intention can be obtained.

[0076] Also, the focus position of the subject image is calculated based on the information of the image circle ICL that the user is referring to as a live view image. Therefore, it is possible to prevent focusing on a subject that the user did not intend.

[0077] FIG. 10 is a diagram showing image data taken at the telephoto end (telephoto side) of the interchangeable lens 200, and shows a state in which the focal length has been changed by the user from the state of FIG. 9 and the focal length L has been changed to the telephoto end (telephoto side). Similar to the state of FIG. 9, the zoom lens driving means 207L and 207R are driven with reference to the focal length correction information 209. For this reason, the focal length R of the image circle ICR is changed by a predetermined amount shorter than the focal length L of the image circle ICL, that is, the angle of view is widened. Preferably, as the focal length changes from the wide side to the telephoto side, the predetermined amount increases.

[0078] The reason will be explained below. The amount of optical axis deviation is considered to be larger on the telephoto side than on the wide side, even if the optical axes are tilted by the same amount. Therefore, the maximum optical axis deviation amount α is set larger on the telephoto side than on the wide side. That is, the focal length correction information 209 is recorded so that the radius r2 of the region 303 shown in FIG. 8(b) becomes larger on the telephoto side than on the wide side. For this reason, as shown in FIG. 10, the size of the corrected ICR, which is the area to be cut out, is set smaller than in the case of FIG. 9.

[0079] By setting it in this way, even when the focal length L is changed from the wide end to the telephoto end, at each focal length L, the focal length R can be appropriately changed, and two images with the same focal length that can be appropriately stereoscopically viewed without any part of the image being cut off can be obtained.

[0080] In addition, even if the amount of optical axis deviation on the tele side is large due to manufacturing errors that vary from unit to unit, such as mounting errors, component tolerances, and assembly errors between the camera body 110 and the interchangeable lens 200, or due to the influence of temperature changes or the like, it is possible to appropriately obtain two images with the same focal length that enable stereoscopic viewing.

[0081] (Second Embodiment) Next, referring to FIG. 11, a second embodiment of the present invention will be described. In this embodiment, each focal length L recorded in the focal length correction information 209 and the focal length R associated therewith have the same value, but instead, the information of the mask 400 associated with each focal length L is included in the focal length correction information 209, which is different from the first embodiment. That is, the storage unit 204 stores the information of the mask 400 corresponding to the focal length of the left optical system 201L (or the right optical system 201R). The mask 400 is used to reduce the display range (angle of view) of the image circle ICL (or the image circle ICR) displayed on the display unit 114. Note that since the other configurations are the same as those in the first embodiment, the description thereof is omitted.

[0082] FIG. 11 is a diagram showing image data taken at the wide end of the interchangeable lens 200, and shows a view of the image circles ICL and ICR projected onto the imaging element 111 as seen from the back of the camera body 110. Here, although the mask 400 is not actually superimposed on the image circle ICL as an image, it is shown superimposed for the sake of explanation.

[0083] In this embodiment, each focal length L stored as the focal length correction information 209 and the focal length R associated therewith have the same value. Therefore, the left optical system 201L and the right optical system 201R are controlled to have the same focal length. However, in reality, a focal length deviation occurs in the image circles ICL and ICR. FIG. 11 shows a state where the actual focal length of the image circle ICR is larger than the actual focal length of the image circle ICL (the angle of view is smaller and the image is taken).

[0084] On the one hand, when the system control unit 117 of the camera body 110 acquires the focal length correction information 209 in step S101 of FIG. 3, the system control unit 117 superimposes and displays the mask 400 on the image of the image circle ICL, and displays the live view image on the display unit 114. The color of the mask 400 is preferably black or semi-transparent black so as to hide the image of the image circle ICL from its outer peripheral part toward the inside with respect to the image circle ICL.

[0085] Here, when the radius of the image circle ICR is r2´, the inner diameter radius r1´ of the mask 400 is represented by the following formula (2).

[0086] r1´ = (r2´ - α) ÷ β …(2) Also in this embodiment, as the focal lengths of the left optical system 201L and the right optical system 201R are changed from the wide side to the tele side, the maximum optical axis deviation amount α is set to increase. Therefore, the inner diameter radius r1´ of the mask 400 changes so as to become smaller as it is changed from the wide side to the tele side.

[0087] In the image data captured in the state of FIG. 11, when recording to the recording unit 116, the focal length correction information 209 is recorded as additional information. Therefore, when performing image correction processing by a predetermined application or program on a computer, the information of the mask 400 can be referred to.

[0088] Regarding the image circle ICL, a corrected ICL trimmed by the mask 400 is created. Regarding the image circle ICR, the magnification deviation amount, the optical axis deviation amount, and the optical axis deviation direction between the corrected ICL and the image circle ICR are calculated by a predetermined algorithm. Then, a range on the image circle ICR corresponding to the focal length of the corrected ICL is cut out as the corrected ICR. Thereafter, image correction processing is performed in which the corrected ICL and the corrected ICR are each enlarged to the same diameter as the original image circles ICL and ICR and arranged side by side left and right, and the final image data is output on a computer.

[0089] According to this embodiment, the first lens 211 of the interchangeable lens 200 can be controlled with the same focal length settings on the left and right. In addition to the effects of the first embodiment, by integrating the zoom lens driving means 207L and 207R, cost reduction can be achieved with a simple configuration. In this embodiment, when displaying the live view image, the mask 400 is superimposed on the image circle ICL. However, the corrected ICL image trimmed by the mask 400 may be enlarged by a predetermined amount and displayed as the live view image.

[0090] Also, in each embodiment, the driving of the first lenses 211L and 211R is controlled by the zoom lens driving means 207L and 207R respectively, but it is not limited to this. For example, the first lenses 211L and 211R may be configured to be extended by a cam barrel. When the user operates the exterior of the interchangeable lens 200, the cam barrel rotates to extend the first lenses 211L and 211R. At this time, similar effects can be expected by individually setting the cam curves of the respective cam barrels so as to have the relationship of the focal lengths L and R according to the focal length correction information 209 in the first embodiment.

[0091] Generally, the camera body 110 is held by the user's right hand, and the interchangeable lens 200 is often operated by the user's left hand. When the interchangeable lens 200 is operated, the left-eye optical system 201L side is more likely to reflect the user's intention. For this reason, in each embodiment, the form of using the image circle ICL for live view display or using the information of the image circle ICL when calculating the focus position of the subject image has been described. However, each embodiment is not limited to this, and the information of the image circle ICR may be used.

[0092] In each embodiment, the image circle ICL to be confirmed as a live view image and the corrected ICL and ICR, which are image data obtained by performing image correction processing on a computer, have been described as being circular, but they may be rectangular. In accordance with commonly used photographs or video expressions, the corrected ICL, ICR, or live view image may be rectangular such that the ratio of the long side to the short side is 3:2 or 16:9.

[0093] In each embodiment, as an example, a mode of changing the focal length by moving the first lens 211 along the first optical axis OA1 has been described, but the present invention is not limited thereto. For example, a mode of moving the second lens 221 along the second optical axis OA2 or a mode of moving the third lens 231 along the third optical axis OA3 may be used. Alternatively, the focal length may be changed by combining a plurality of these lenses.

[0094] According to each embodiment, it is possible to provide a lens device and an imaging system capable of acquiring an appropriate stereoscopic captured image reflecting the user's imaging intention.

[0095] The disclosure of each embodiment includes the following configurations. (Configuration 1) A lens device detachable from an imaging device, a first optical system, a second optical system arranged in parallel with the first optical system, and a lens mount attachable to the imaging device, wherein the first optical system forms a first image at a first focal length, and the second optical system forms a second image corresponding to the first image at a second focal length shorter than the first focal length. A lens device characterized by this. (Configuration 2) The lens device according to Configuration 1, wherein the second optical system forms the second image simultaneously with the formation of the first image by the first optical system. (Configuration 3) The second focal length is shorter than the first focal length by a predetermined amount, The predetermined amount is an amount that can cut out, from the second image, a third image formed by the second optical system at the first focal length so as to correct the deviation of the optical axis of the second optical system with respect to the first optical system. The lens device according to Configuration 1 or 2. (Configuration 4) The focal lengths of the first optical system and the second optical system are variable, The focal length of the second optical system changes in conjunction with the change in the focal length of the first optical system, At at least one of the tele end or the wide end, the second focal length is shorter than the first focal length by the predetermined amount. The lens device according to Configuration 3. (Configuration 5) As the focal length changes from the wide side to the tele side, the predetermined amount increases. The lens device according to Configuration 3 or 4. (Configuration 6) The first image is used for calculating the focus position. The lens device according to any one of Configurations 1 to 5. (Configuration 7) A lens device detachable from an imaging device, A first optical system that forms a first image, A second optical system that is arranged in parallel with the first optical system and forms a second image, A lens mount attachable to the imaging device, A storage unit that stores information on a mask corresponding to the focal length of the first optical system, and has, The mask is used to reduce the display range of the first image. The lens device. (Configuration 8) The first optical system and the second optical system have the same focal length and form the first image and the second image, respectively. The lens device according to Configuration 7. (Configuration 9) A lens device detachable from an imaging device, A first optical system, A second optical system arranged in parallel with the first optical system; a lens mount attachable to the imaging device, and having: The first optical system and the second optical system are each a bending optical system having a first reflecting surface and a second reflecting surface; The first optical system and the second optical system each have, in order from the object side to the image side, a first optical axis, a second optical axis that is reflected by the first reflecting surface and bent from the first optical axis, and a third optical axis that is closest to the image plane and is reflected by the second reflecting surface and bent from the second optical axis; The first optical axis of each of the first optical system and the second optical system is outside the mount diameter of the lens mount; The third optical axis of each of the first optical system and the second optical system is inside the mount diameter; The focal lengths of the first optical system and the second optical system are variable; A lens device, characterized in that when the focal length of one of the first optical system or the second optical system is changed, the focal length of the other of the first optical system or the second optical system is changed in the same direction. (Configuration 10) The lens device according to Configuration 9, characterized in that the lens device communicates information regarding at least one of the focal lengths of the first optical system or the second optical system, or information regarding a change in the focal length, with the imaging device. (Configuration 11) The lens device according to Configuration 9 or 10, characterized in that the lens device communicates information regarding the focal lengths of both the first optical system and the second optical system with the imaging device. (Configuration 12) An imaging device; An imaging system, characterized in that it includes the lens device according to any one of Configurations 1 to 8. (Configuration 13) The imaging device has a display unit; The imaging system according to Configuration 12, characterized in that the first image is displayed on the display unit during imaging preparation and during imaging. (Configuration 14) The imaging device has a display unit, The imaging system according to Configuration 12, wherein image processing is performed on the first image so that the first image appears to have a longer focal length than the second image, and the processed image is displayed on the display unit. (Configuration 15) The imaging device has an image sensor, When the lens device is attached to the imaging device, the first optical system and the second optical system are arranged in parallel along the long side direction of the image sensor. The imaging system according to any one of Configurations 12 to 15, wherein the first optical system is located on the left side when viewed from the back of the imaging device. (Configuration 16) An imaging device, An imaging system comprising the imaging device and the lens device according to any one of Configurations 9 to 11.

[0096] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist thereof.

Description of Reference Numerals

[0097] 110 Camera body (imaging device) 200 Interchangeable lens (lens device) 201L Left-eye optical system (first optical system) 201R Right-eye optical system (second optical system) 202 Lens mount ICL Image circle (first image) ICR Image circle (second image)

Claims

1. A lens device detachable from an imaging device, comprising: a first optical system; a second optical system arranged in parallel with the first optical system; a lens mount attachable to the imaging device, wherein the first optical system forms a first image at a first focal length, and the second optical system forms a second image corresponding to the first image at a second focal length shorter than the first focal length.

2. The lens device according to claim 1, wherein the second optical system forms the second image simultaneously with the formation of the first image by the first optical system.

3. The second focal length is shorter than the first focal length by a predetermined amount, wherein the predetermined amount is an amount such that a third image formed by the second optical system at the first focal length can be cut out from the second image so as to correct the deviation of the optical axis of the second optical system with respect to the first optical system.

4. The focal lengths of the first optical system and the second optical system are variable, and the focal length of the second optical system changes in conjunction with the change in the focal length of the first optical system, wherein at at least one of the tele end or the wide end, the second focal length is shorter than the first focal length by the predetermined amount.

5. The lens device according to claim 3, wherein the predetermined amount increases as the focal length changes from the wide side to the tele side.

6. The lens device according to claim 1, wherein the first image is used for calculating the focus position.

7. A lens device detachable from an imaging device, comprising: a first optical system that forms a first image; a second optical system arranged in parallel with the first optical system and forming a second image; a lens mount attachable to the imaging device; a storage unit that stores information on a mask corresponding to the focal length of the first optical system, wherein the mask is used to reduce the display range of the first image.

8. The lens device according to claim 7, wherein the first optical system and the second optical system have the same focal length and form the first image and the second image, respectively.

9. A lens device detachable from an imaging device, comprising: a first optical system; A second optical system arranged in parallel with the first optical system; A lens mount attachable to the imaging device, and having, The first optical system and the second optical system are each a bending optical system having a first reflecting surface and a second reflecting surface, The first optical system and the second optical system each have, in order from the object side to the image side, a first optical axis, a second optical axis reflected by the first reflecting surface and bent from the first optical axis, and a third optical axis closest to the image plane and reflected by the second reflecting surface and bent from the second optical axis, The first optical axis of each of the first optical system and the second optical system is outside the mount diameter of the lens mount, The third optical axis of each of the first optical system and the second optical system is inside the mount diameter, The focal lengths of the first optical system and the second optical system are variable, A lens device, characterized in that when the focal length of one of the first optical system or the second optical system is changed, the focal length of the other of the first optical system or the second optical system is changed in the same direction.

10. The lens device according to claim 9, characterized in that the lens device communicates information regarding at least one focal length of the first optical system or the second optical system, or information regarding a change in the focal length, with the imaging device.

11. The lens device according to claim 9, characterized in that the lens device communicates information regarding the focal lengths of both the first optical system and the second optical system with the imaging device.

12. An imaging device, An imaging system, comprising the lens device according to any one of claims 1 to 8.

13. The imaging device has a display unit, The imaging system according to claim 12, characterized in that the first image is displayed on the display unit during imaging preparation and during imaging.

14. The imaging device has a display unit, The imaging system according to claim 12, characterized in that image processing is performed on the first image so that the first image appears to have a longer focal length than the second image, and the processed image is displayed on the display unit.

15. The imaging device has an image sensor, When the lens device is attached to the imaging device, the first optical system and the second optical system are arranged in parallel along the long side direction of the image sensor. The imaging system according to claim 12, wherein the first optical system is located on the left side when viewed from the back of the imaging device. **Claim 16** An imaging device, and a lens device according to any one of claims 9 to 11, the imaging system being characterized by having the same.

Images