Control device, lens device, control method, and program

Abstract

To provide a control device capable of highly accurate focusing by a focus preset function.SOLUTION: A control device (105) includes: acquisition means (105a) for acquiring reference focus position information on a focus lens group using a defocus amount and position characteristic data of a focus lens group (104) when first operation means (112) is operated; and determination means (105b) for determining a target position of a focus lens group using the reference focus position information and the position characteristic data when second operation means (113) is operated. The position characteristic data is data indicating a relationship between a position of the focus lens group for each subject distance and a state of an optical system (101) including the focus lens group, and the reference focus position information is focus position information in a second state where resolution at the position of the focus lens group is higher than that in a first state of the optical system when the first operation means is operated.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device, a lens device, a control method, and a program. [Background technology]

[0002] Lens devices with a focus preset function are known. Using the focus preset function, a user can instantly reproduce a desired focus position. The focus preset function is implemented using position characteristic data that indicates the relationship between the focal length and the position of the focus lens for each subject distance. However, the position characteristic data often has a lower resolution for the focus lens position on the wide-angle side (WIDE side) than on the telephoto side (TELE side).

[0003] Therefore, when executing the focus preset function, if the focus position is stored at the wide-angle side, and then the zoom is performed at the telephoto side, and the stored focus position is then reproduced, the focus position is stored at a focal length with low resolution and reproduced at a focal length with high resolution, which results in inability to perform high-precision focusing.

[0004] Patent Document 1 discloses a method of not driving the focus lens when the focal length during the focus position return operation is on the telephoto side compared to the focal length during focus storage. Patent Document 2 discloses a method of determining whether or not the focal length during the focus position return operation is likely to cause focus deviation, and changing the display depending on the determination result. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4590892 [Patent Document 2] Patent No. 4590891 Summary of the Invention [Problem to be solved by the invention]

[0006] In the methods disclosed in Patent Documents 1 and 2, depending on the state of the optical system, such as the focal length and the amount of aberration, it may not be possible to perform highly accurate focusing using the focus preset function.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a control device, a lens device, a control method, and a program that enable highly accurate focusing using a focus preset function. [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided a control device for controlling a lens device having first and second operating means and a lens group that moves during focusing, the control device comprising: an acquisition means for acquiring reference position information of the lens group using characteristic information indicating a defocus amount of the lens device and a relationship between a position of the lens group and a subject distance when the first operating means is operated; and a determination means for determining a target position of the lens group using the characteristic information and the reference position information when the second operating means is operated, the reference position information being information regarding the position of the lens group in a second state in which the range of movement of the lens group is wider than in a first state of the lens device when the first operating means is operated. The second state is a state in which the amount of aberration of the lens device is larger than that of the first state. .

[0009] Other objects and features of the present invention are illustrated in the following examples. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a control device, a lens device, a control method, and a program that enable highly accurate focusing using a focus preset function. [Brief explanation of the drawings]

[0011] [Figure 1]1 is a block diagram of a camera system according to a first embodiment. [Figure 2] 4 is a graph of position characteristic data in Example 1. [Figure 3] 4 is a flowchart of AF drive control in the first embodiment. [Figure 4] 4 is a flowchart of a cam interpolation ratio storage control in the first embodiment. [Figure 5] 10 is a flowchart of preset position reproduction control in the first embodiment. [Figure 6] FIG. 3 is an explanatory diagram of focus preset control in the first embodiment. [Figure 7] FIG. 10 is a block diagram of a camera system according to a second embodiment. [Figure 8] 10 is a graph of position characteristic data in Example 2. [Figure 9] 10 is a flowchart of focus lens drive control during AF drive in the second embodiment. [Figure 10] FIG. 10 is a block diagram of a camera system according to a third embodiment. [Figure 11] 10 is a graph of position characteristic data in Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals, and redundant explanations will be omitted. [Example]

[0013] First, a camera system (image capturing system) according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a block diagram of a camera system 10 according to this embodiment.

[0014] The camera system 10 is an interchangeable lens camera comprising a camera body (imaging device) 200 and a lens device (interchangeable lens) 100 that is detachable from the camera body 200, but this embodiment can also be applied to an integrated lens camera. The lens device 100 and the camera body 200 are mechanically and electrically connected via a mount (not shown), and power is supplied and mutual communication between the lens device 100 and the camera body 200 is performed via terminals provided on the mount.

[0015] The lens device 100 has an optical system (image pickup optical system) 101 including multiple lenses. The optical system 101 forms a subject image (optical image) and focuses it on an image pickup element 201. The optical system 101 also has a variable magnification lens (zoom lens group) 102, an aperture 103, and a first focus lens (focus lens group) 104. The variable magnification lens 102 can be moved in a direction along an optical axis OA (optical axis direction) by operating a zoom operation unit 110, thereby changing the focal length of the lens device 100. A zoom position detection unit 111 detects the position of the variable magnification lens 102 and transmits the position of the variable magnification lens 102 to a lens control unit 105. The aperture (aperture stop) 103 has aperture blades and is driven by an aperture drive unit 106 to adjust the amount of light passing through the optical system 101 and entering the image pickup element 201.

[0016] The first focus lens 104 is driven in the optical axis direction by a first focus lens driver 107 having an actuator. The first focus lens 104 has the functions of focusing the image formed on the image sensor 201 and adjusting aberrations. The actuator includes a small ultrasonic motor (vibration motor) such as a NanoUSM (Nano Ultra Sonic Motor). In this configuration, the first focus lens 104 moves linearly on a slider due to ultrasonic vibration energy, driving the first focus lens 104, which is connected to a rack member. The first focus lens position detector 108 has a position detection sensor including a fixed part and a movable part. The first focus lens position detector 108 emits LED light from the fixed part and receives light reflected by a different pattern scale on the movable part with a photodiode in the fixed part. In this way, the first focus lens position detector 108 detects the position of the first focus lens 104 and transmits the position data to the lens controller 105. In this embodiment, the first focus lens position detector 108 detects the absolute position of the first focus lens 104, but this is not limiting, and the first focus lens position detector 108 may detect the relative position of the first focus lens.

[0017] The memory 109 is a storage means such as a ROM (Read Only Memory) or a RAM (Random Access Memory), and stores position characteristic data of the first focus lens 104. The position characteristic data indicates the same subject distance (distance from the image plane to the subject) for each focal length, and is position data of the first focus lens 104 that is optically determined so as to achieve good focus and reduced aberration.

[0018] Lens control unit 105 is a computer (control device) equipped with a CPU, etc. Lens control unit 105 transmits information such as the drive amount received from camera body 200 to diaphragm drive unit 106 and first focus lens drive unit 107, respectively, and controls the opening of diaphragm 103 and the position of first focus lens 104 by closed-loop control.

[0019] Focus position storage operation unit (first operation means) 112 and focus position reproduction operation unit (second operation means) 113 are, for example, button switches, and transmit a signal to lens control unit 105 in response to a user's operation. When lens control unit 105 is notified that focus position storage operation unit 112 has been operated, lens control unit 105 acquires the current position of first focus lens 104 from first focus lens position detection unit 108 and stores it in memory 109. When lens control unit 105 is notified that focus position reproduction operation unit 113 has been operated, lens control unit 105 controls first focus lens driving unit 107 to reproduce the position of first focus lens 104 stored in memory 109. In this way, focus position storage operation unit 112 is operated by the user to store the position of first focus lens 104 in the focus preset function. Furthermore, focus position reproduction operation unit 113 is operated by the user to reproduce the position of first focus lens 104 in the focus preset function.

[0020] Lens control unit 105 has acquisition means 105a and determination means 105b. When focus position storage operation unit 112 is operated, acquisition means 105a acquires reference focus position information of first focus lens 104 using the defocus amount and position characteristic data of first focus lens 104. When focus position reproduction operation unit 113 is operated, determination means determines a target position of first focus lens 104 using the reference focus position information and the position characteristic data.

[0021] The camera body 200 has an image sensor 201, a signal processing unit 202, a recording processing unit 203, a defocus detection unit 204, a camera control unit 205, a memory 206, an electronic viewfinder 207, and a display unit 208. The image sensor 201 converts an optical image formed by the optical system 101 of the lens apparatus 100 into an electrical signal by photoelectric conversion and transmits it to the signal processing unit 202. The signal processing unit 202 receives the electrical signal (analog signal) from the image sensor 201 and converts it into a digital signal. The signal processing unit 202 also performs image processing and transmits the image data to the recording processing unit 203. The recording processing unit 203 displays the image data transmitted as a digital signal on the electronic viewfinder 207 or the display unit 208.

[0022] A defocus detection unit 204 detects defocus and transmits the result to a camera control unit 205. The pixels of the image sensor 201 can also be used for distance measurement (focus detection), and the amount of defocus is detected by measuring the phase difference between the photoelectric conversion results of adjacent pixels that divide the pupil region.

[0023] The camera control unit 205 is a computer such as a CPU, and is electrically connected to the recording processing unit 203, the defocus detection unit 204, and the memory 206. The camera control unit 205 reads and executes programs recorded in the memory 206, and also communicates information necessary for autofocus control with the lens control unit 105. The camera control unit 205 also controls the camera body 200 in response to input signals from a camera operation unit (not shown), such as a shooting switch and various setting switches.

[0024] Next, we will explain the control when the zoom operation unit 110 is operated by a user. The zoom operation unit 110 has a configuration that can rotate on the side of the lens device 100, for example, like a zoom ring, and an internal zoom encoder and the like move in conjunction with the rotation, causing the variable magnification lens 102 to move according to a designed cam. When the variable magnification lens 102 moves, the zoom position detection unit 111 detects the zoom position and notifies the lens control unit 105 of the current zoom position.

[0025] Here, the position characteristic data of the first focus lens 104 will be described with reference to Fig. 2. Fig. 2 is a graph of position characteristic data that represents the position (cam data) of the trajectory of the first focus lens 104 at the same subject distance for each focal length (zoom position, state of the optical system 101). The position characteristic data is cam data that indicates the relationship between the position of the first focus lens 104 for each subject distance and the state of the optical system 101 (focal length in this embodiment). In Fig. 2, the horizontal axis represents the focal length (zoom position), and the vertical axis represents the focus lens position. As described above, the position characteristic data shown in Fig. 2 is stored in memory 109.

[0026] For example, consider a case where the current zoom position is at the telephoto end, the subject distance is at the closest point (MOD), and the zoom position is moved to the wide-angle end by a zoom operation. Since the current position of first focus lens 104 is at the telephoto end and the subject distance is at MOD, the current position of first focus lens 104 is Pt in FIG.

[0027] Lens control unit 105 monitors the zoom position detected by zoom position detection unit 111 at a predetermined cycle (control cycle). When zoom position detection unit 111 detects movement of variable magnification lens 102, lens control unit 105 refers to position characteristic data stored in memory 109. Then, lens control unit 105 drives first focus lens 104 using first focus lens driving unit 107 to a position of first focus lens 104 (first focus lens position) that corresponds to the current zoom position and subject distance.

[0028] However, the memory 109 does not store the positions of the first focus lens 104 for all subject distances and zoom positions as position characteristic data. Because the memory 109 has a limited storage capacity, the position characteristic data includes only position data for the first focus lens 104 for several representative subject distances (six subject distances in FIG. 2), as indicated by the solid lines in FIG. 2. The zoom position direction (horizontal axis direction in FIG. 2) is also indicated by a solid line, but this is a finite amount of data. Therefore, if a certain position of the first focus lens 104 is not included in the position characteristic data, the lens control unit 105 calculates the adjacent cam data and its ratio (cam interpolation ratio), and stores the calculated ratio in a storage unit such as the memory 109. By calculating the cam interpolation ratio, it is possible to calculate an appropriate position of the first focus lens 104 even when the zoom position changes, and it is possible to track the same subject distance at a predetermined cycle (control cycle).

[0029] Through the above series of controls, the position of the first focus lens 104 is driven to track the solid line MOD in Figure 2 in response to the user's zoom operation, and reaches position Pw at the Wide end. This type of control is called zoom tracking control.

[0030] Next, with reference to Fig. 3, autofocus drive control (AF drive control) by lens control unit 105 when a drive command for first focus lens 104 is transmitted from camera body 200 to lens device 100 will be described. Fig. 3 is a flowchart of AF drive control. Each step in Fig. 3 is mainly executed by lens control unit 105.

[0031] When the camera control unit 205 receives an AF drive command from the user, the defocus detection unit 204 calculates the defocus amount, which is the distance from the in-focus point to the imaging plane, using phase difference AF, etc. Then, in step S301, the lens control unit 105 acquires the defocus amount from the camera control unit 205 via the mount.

[0032] Next, in step S302, the lens control unit 105 calculates a reference drive amount. The reference drive amount is the drive amount of the first focus lens 104 at a focal length (zoom position) where the range of motion of the first focus lens 104 is widest (highest resolution) in the optical design, where the object distance is driven from infinity (INF) to the closest distance (MOD). The memory 109 stores sensitivity data. The sensitivity is a ratio indicating how much the defocus amount changes with respect to the drive amount of the first focus lens 104. The memory 109 stores the sensitivity as a coefficient for each focal length (zoom position). The lens control unit 105 can convert the defocus amount by the sensitivity into the drive amount of the first focus lens 104 at an arbitrary zoom position. In this embodiment, the lens control unit 105 calculates the drive amount (reference drive amount) of the first focus lens 104 at the zoom position with the highest resolution using the defocus amount and the sensitivity.

[0033] Next, in step S303, the lens control unit 105 calculates a reference cam interpolation ratio using the reference drive amount calculated in step S302. The reference cam interpolation ratio is a cam interpolation ratio (reference focus position information) for the position of the first focus lens 104 obtained by adding the reference drive amount to the current position of the first focus lens 104. The reference cam interpolation ratio calculated by the lens control unit 105 is stored in the memory 109.

[0034] Next, in step S304, the lens control unit 105 converts the defocus amount acquired in step S301 into a drive amount (current drive amount) of the first focus lens 104 at the current zoom position. That is, the lens control unit 105 calculates the current drive amount using the defocus amount, sensitivity, and position characteristic data, similar to step S302.

[0035] Next, in step S305, lens control unit 105 adds the current position of first focus lens 104 to the current drive amount calculated in step S304, and determines a target position of first focus lens 104. Then, lens control unit 105 controls first focus lens drive unit 107 to drive first focus lens 104 to the target position.

[0036] In this embodiment, the reference drive amount is described as the drive amount at the zoom position (focal length) with the highest resolution, but is not limited to this. The reference drive amount may be the drive amount at a second zoom position (second focal length) of the zoom positions (focal lengths) of the camera system 10, where the position resolution of the first focus lens 104 is higher than that at the first zoom position (first focal length).

[0037] Next, the focus preset control in this embodiment will be described with reference to Fig. 4. The lens control unit 105 stores the cam interpolation ratio in the memory 109 at a predetermined cycle (control cycle). Fig. 4 is a flowchart of the cam interpolation ratio storage control. Each step in Fig. 4 is mainly executed by the lens control unit 105.

[0038] First, in steps S401 and S402, the first focus lens 104 is driven to change the cam interpolation ratio in accordance with the AF drive described with reference to FIG. 3 and the amount of operation using a manual ring or the like. In this embodiment, consideration is given to cases where manual drive (MF drive) has been performed and cases where it has not. That is, if AF drive has not been performed in step S401, or if AF drive has been performed in step S401 and MF drive has been performed in step S402, the process proceeds to step S403. On the other hand, if AF drive has been performed in step S401 and MF drive has not been performed in step S402, the process proceeds to step S404.

[0039] In step S403, the lens control unit 105 calculates a current cam interpolation ratio using the current position and position characteristic data of the first focus lens 104 because the reference cam interpolation ratio due to AF driving could not be calculated or the subject distance has changed due to MF driving. The current cam interpolation ratio is the cam interpolation ratio calculated at the current zoom position. Meanwhile, in step S404, because AF driving has been performed last, the lens control unit 105 acquires the reference cam interpolation ratio (reference focus position information) calculated with the highest resolution.

[0040] Next, in step S405, the lens control unit 105 determines whether the user has operated (pressed) the focus position storage operation unit 112. If the focus position storage operation unit 112 has not been pressed, the process returns to step S401. On the other hand, if the focus position storage operation unit 112 has been pressed, the lens control unit 105 stores the current cam interpolation ratio acquired in step S403 or the reference cam interpolation ratio acquired in step S404 in the memory 109 as a preset cam interpolation ratio.

[0041] Next, control (preset position reproduction control) when the user operates the focus position reproduction operation unit 113 will be described with reference to Fig. 5. Fig. 5 is a flowchart of the preset position reproduction control. Each step in Fig. 5 is mainly executed by the lens control unit 105.

[0042] First, in step S501, the lens control unit 105 determines whether or not a preset cam interpolation ratio is stored in the memory 109. If the preset cam interpolation ratio is not stored in the memory 109, it means that the focus position storage operation unit 112 has not been operated in conjunction with the operation of the focus position reproduction operation unit 113. In this case, the lens control unit 105 does not drive the first focus lens 104. On the other hand, if the preset cam interpolation ratio is stored in the memory 109, it means that the focus position storage operation unit 112 has been operated before the operation of the focus position reproduction operation unit 113. In this case, the process proceeds to step S502.

[0043] In step S502, lens control unit 105 calculates a target position (final target position) of first focus lens 104 using the preset cam interpolation ratio and position characteristic data stored in memory 109. Subsequently, in step S503, lens control unit 105 controls first focus lens driving unit 107 to drive first focus lens 104 to the target position calculated in step S502.

[0044] Next, the effects of this embodiment will be described with reference to Fig. 6. Fig. 6 is an explanatory diagram of focus preset control, showing an excerpt of position characteristic data. Cam data (C1) when the subject distance is 1.0 m and cam data (C2) for MOD are shown by solid lines. In this embodiment, the position resolution of the first focus lens 104 is highest at the Tele end.

[0045] Here, for example, consider a case where the current zoom position is at the Wide end and the current focus position is MOD. At this time, the current position of the first focus lens 104 is position P6w in FIG. 6. When AF drive is performed (when an AF drive command is received), the lens control unit 105 acquires the defocus amount from the camera body 200. The calculated reference drive amount is Dt, and the interpolation ratio is 0.5, meaning that the subject distance is midway between C1 and C2. However, because the resolution at the Wide end is lower than the resolution at the Telephoto end, the accuracy of the cam interpolation ratio decreases when converted to a current drive amount Dw equivalent to the Wide end. As a result, the current cam interpolation ratio is calculated to be 0.7, and the first focus lens 104 is controlled to position P6w1.

[0046] Here, when the focus position storage operation unit 112 is operated and the preset cam interpolation ratio is stored, the cam interpolation ratio at the Tele end (the reference cam interpolation ratio) is stored as 0.5. In this state, suppose that the zoom operation unit 110 is operated and the zoom position reaches the Tele end. Here, when the focus position reproduction operation unit 113 is operated, the preset cam interpolation ratio is 0.5, so the target position of the first focus lens 104 becomes P6t1, which is midway between C1 and C2 at the Tele end, and the correct subject distance can be controlled.

[0047] In the case of the conventional control method, the reference cam interpolation ratio is not calculated, but the current cam interpolation ratio is used, so the preset cam interpolation ratio becomes 0.7, and when the focus position is reproduced at the Tele end, it is reproduced to position P6t1', causing focus deviation. On the other hand, according to this embodiment, in the lens device 100 including the magnification variable lens 102, it is possible to reduce focus deviation when the focus position is stored on the wide-angle side with low resolution and then reproduced on the telephoto side with higher resolution. [Example]

[0048] Next, a camera system according to a second embodiment of the present invention will be described with reference to Fig. 7. Fig. 7 is a block diagram of a camera system 10a according to this embodiment.

[0049] Camera system 10a is configured to include a camera body (imaging device) 200 and a lens device (interchangeable lens) 100a that is detachable from camera body 200. Camera system 10a (lens device 100a) of this embodiment differs from camera system 10 (lens device 100) of Embodiment 1 in that it includes a second focus lens 701, a second focus lens driving unit 702, and a second focus lens position detection unit 703. That is, lens device 100a is composed of two focus lens groups, a first focus lens (first focus lens group) 104 and a second focus lens (second focus lens group) 701, which are movable independently in the optical axis direction. Therefore, in this embodiment, focus position information is composite focus position information of first focus lens 104 and second focus lens 701.

[0050] The first focus lens (first focus lens group) 104 is a lens group that mainly corrects focus, and the second focus lens (second focus lens group) 701 is a lens group that mainly corrects aberration. The second focus lens driver 702 drives the second focus lens 701. Like the first focus lens driver 107, the second focus lens driver 702 has a small ultrasonic motor (vibration motor) such as a NanoUSM (Nano Ultra Sonic Motor). The second focus lens driver 702 moves linearly on a slider using vibration energy from ultrasonic waves, driving the second focus lens 701 that is connected to a rack member. Like the first focus lens position detector 108, the second focus lens position detector 703 has a position detection sensor that includes a fixed part and a movable part. The second focus lens position detection unit 703 emits LED light from the fixed part, receives the light reflected by a different pattern scale on the movable part with a photodiode in the fixed part, detects the position of the second focus lens 701, and transmits the position data to the lens control unit 105.

[0051] Here, the position characteristic data of this embodiment will be described with reference to FIGS. 8(a) and 8(b). FIG. 8(a) is a graph of first position characteristic data relating to the position of the first focus lens 104, and FIG. 8(b) is a graph of second position characteristic data relating to the second focus lens 701. The first position characteristic data indicates the relationship between subject distance and focal length (zoom position, state of the optical system 101) relating to the position of the first focus lens 104. The second position characteristic data indicates the relationship between subject distance and focal length (zoom position, state of the optical system 101) relating to the position of the second focus lens 701. In FIGS. 8(a) and 8(b), the horizontal axis indicates focal length, and the vertical axis indicates the first focus lens position or the second focus lens position, respectively. Seven types of subject distance data are provided: closest MOD, 0.7 m, 1.0 m, 3.0 m, 5.0 m, and infinity INF.

[0052] The memory 109 must store zoom-focus position data within a limited data range. For example, when the lens control unit 105 receives a command to move to a position between 2.0 m and 4.0 m, the lens control unit 105 performs an interpolation operation on the zoom-focus position data of 1.0 m and 3.0 m to determine the lens position at 2.0 m. Similarly, the lens control unit 105 calculates the drive amount of the first focus lens 104 and the second focus lens 701 by interpolating the focus lens position at 4.0 m from the data of 3.0 m and 5.0 m. Although the focal length is graphed as continuous data, the amount of data that can be stored in the memory 109 is limited, so the focal length is also stored as a finite number of data. As with the relationship between subject distance and focus lens position, the focus lens position at the corresponding focal length can be determined by interpolating adjacent data.

[0053] Next, the AF drive control in this embodiment will be described. The AF drive control in this embodiment is different from the AF drive control in embodiment 1 in step S305 (focus lens drive control) in Fig. 3, but the other steps are the same. For this reason, in this embodiment, only the focus lens drive control will be described, and other descriptions will be omitted.

[0054] FIG. 9 is a flowchart of focus lens drive control. Each step in FIG. 9 is mainly executed by the lens control unit 105. First, in step S901, the lens control unit 105 calculates a target cam interpolation ratio. In a previous stage, the current drive amount of the first focus lens 104 is calculated. By adding this to the current position of the first focus lens 104, the target position of the first focus lens 104 can be calculated. Then, the lens control unit 105 calculates the cam interpolation ratio of the target position (target cam interpolation ratio). Furthermore, the lens control unit 105 can calculate the target position of the second focus lens 701 using the target cam interpolation ratio and the second position characteristic data.

[0055] Next, in step S902, lens control unit 105 controls first focus lens driving unit 107 and second focus lens driving unit 702 to drive first focus lens 104 and second focus lens 701 to their respective target positions. At this time, it is necessary to synchronize first focus lens 104 and second focus lens 701. For this reason, lens control unit 105 determines and controls, at a predetermined cycle (control cycle), the target positions of first focus lens 104 and second focus lens 701 that result in the same focal length and subject distance, respectively, from the first position characteristic data and the second position characteristic data.

[0056] Next, the focus preset drive of this embodiment will be described. The cam interpolation ratio storage control shown in FIG. 4 is the same as in the first embodiment. The preset position reproduction control differs from the first embodiment with respect to steps S502 and S503 in FIG. 5. In this embodiment, the target positions of the first focus lens 104 and the second focus lens 701 are calculated using the preset cam interpolation ratio, the first position characteristic data, and the second position characteristic data. In the subsequent steps, the lens control unit 105 controls the first focus lens driving unit 107 and the second focus lens driving unit 702 to drive the first focus lens 104 and the second focus lens 701 so that they reach their respective target positions.

[0057] According to this embodiment, for a lens device having two focus lens groups, even when using a focus preset function that stores focus on the wide-angle side and reproduces it on the telephoto side, it is possible to reduce focus deviation and aberration deviation. [Example]

[0058] Next, a camera system according to a third embodiment of the present invention will be described with reference to Fig. 10. Fig. 10 is a block diagram of a camera system 10b according to this embodiment.

[0059] Camera system 10b is configured to include a camera body (imaging device) 200 and a lens device (interchangeable lens) 100b that is detachable from camera body 200. Camera system 10b (lens device 100b) of this embodiment differs from camera system 10a (lens device 100a) of Example 2 in that it includes an aberration operation unit 1001 and an aberration change amount detection unit 1002, but does not include a variable magnification lens 102 or a zoom position detection unit 111.

[0060] The aberration operation unit 1001 is an aberration changing means that changes the amount of aberration, and is, for example, a smoothly rotatable ring that fits around the lens barrel. In response to a user's operation, the aberration operation unit 1001 transmits the amount of rotation to the aberration change amount detection unit 1002. The aberration change amount detection unit 1002 transmits the amount of rotation of the aberration operation unit 1001 transmitted from the aberration operation unit 1001 to the lens control unit 105 as the amount of aberration change.

[0061] Next, the position characteristic data in this embodiment will be described with reference to Figures 11(a) and (b). Figures 11(a) and (b) are graphs of the position characteristic data (first position characteristic data, second position characteristic data) in this embodiment. The vertical axes of Figures 11(a) and (b) indicate the first focus lens position and the second focus lens position, respectively, as in Example 2. On the other hand, the horizontal axes of Figures 11(a) and (b) indicate the amount of aberration (the state of the optical system) rather than the focal length.

[0062] The first position characteristic data indicates the relationship between the subject distance and the amount of aberration with respect to the position of the first focus lens 104. The second position characteristic data indicates the relationship between the subject distance and the amount of aberration with respect to the position of the second focus lens 701. In other words, the data indicates the positions of the first focus lens 104 and the second focus lens 701 that are in focus with a certain amount of aberration for each representative point of the subject distance. In the zoom tracking control described in the first embodiment, the detected focal length (zoom position) is replaced with the amount of aberration in this embodiment. According to this embodiment, the user can arbitrarily change the amount of aberration while maintaining focus.

[0063] The AF drive in this embodiment differs from that in the second embodiment in terms of the reference drive amount. The reference drive amount in this embodiment is the drive amount of the first focus lens 104 at the aberration amount with the widest range of motion (highest resolution) of the first focus lens 104, which drives from infinity to the closest subject distance in the optical design. When cam interpolation ratio storage control is performed using the reference drive amount, the reference cam interpolation ratio becomes the cam interpolation ratio calculated at the aberration amount with the highest position resolution of the first focus lens 104. Using this reference cam interpolation ratio, the same cam interpolation ratio storage control as in the second embodiment is performed. Note that the current cam interpolation ratio in this embodiment indicates the cam interpolation ratio at the current aberration amount. The preset position reproduction control is the same as in the second embodiment.

[0064] According to this embodiment, even when a lens device having two focus lens groups performs focus preset driving in which the focus is stored when the aberration is excessive and the focus is reproduced when the aberration is insufficient, it is possible to reduce focus deviation and bring the aberration closer to the correct amount.

[0065] As described above, in each embodiment, the control device (lens control unit 105) includes an acquisition unit 105a and a determination unit 105b. When the first operation unit is operated, the acquisition unit 105a acquires reference focus position information of the focus lens group using the defocus amount and position characteristic data of the focus lens group. When the second operation unit is operated, the determination unit 105b determines a target position of the focus lens group using the reference focus position information and the position characteristic data. Here, the reference focus position information is focus position information in a second state in which the position resolution of the focus lens group is higher than that of the first state of the optical system when the first operation unit is operated. Note that in each embodiment, at least some of the functions of the acquisition unit 105a and the determination unit 105b may be configured to be executed by the camera control unit 205.

[0066] Preferably, the state of the optical system (first state, second state) is the focal length (first focal length, second focal length) of the optical system. The second state (second focal length) is, for example, the state of the optical system at the telephoto end, but is not limited to this, and the second state (second focal length) may be a state on the telephoto side more than the first state (first focal length). Alternatively, preferably, the state of the optical system is the amount of aberration of the optical system.

[0067] Preferably, the acquisition unit 105a acquires reference focus position information based on an AF drive command. Also preferably, the focus position information is information regarding the ratio between two adjacent subject distance data in the position characteristic data (for example, the center position between the subject distance data of infinity INF and the subject distance data of 5.0 m in FIG. 2). Also preferably, the determination unit 105b determines the target position of the focus lens group at a predetermined cycle.

[0068] (Other Examples) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0069] According to each embodiment, it is possible to provide a control device, a lens device, a control method, and a program that enable highly accurate focusing using a focus preset function.

[0070] 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 of the present invention. [Explanation of symbols]

[0071] 101 Optical system 104 First focus lens (focus lens group) 105 Lens control unit (control device) 105a Acquisition method 105b Determination means 112 Focus position storage operation unit (first operation means) 113 Focus position reproduction operation unit (second operation means) 701 Second focus lens (focus lens group)

Claims

1. A control device for controlling a lens device having first and second operating means and a lens group that moves during focusing, an acquisition unit that acquires reference position information of the lens group using characteristic information indicating a defocus amount of the lens device and a relationship between a position of the lens group and a subject distance when the first operation unit is operated; a determining unit that determines a target position of the lens group by using the characteristic information and the reference position information when the second operating unit is operated, the reference position information is information about a position of the lens group in a second state in which a movable range of the lens group is wider than that of the first state of the lens device when the first operation means is operated, The control device according to claim 1, wherein the second state is a state in which the amount of aberration of the lens device is greater than that of the first state.

2. 2. The control device according to claim 1, wherein the second state is a state in which the focal length of the lens device is longer than that of the first state.

3. 3. The control device according to claim 2, wherein the second state corresponds to the telephoto end of the lens device.

4. 4. The control device according to claim 1, wherein the information about the position of the lens group is information about a ratio between two adjacent object distance data items included in the characteristic information.

5. the position of the lens group is recorded by operating the first operating means; 5. The control device according to claim 1, wherein the lens group is moved to the recorded position by operating the second operating means.

6. A lens device having first and second operating means, a first lens group that moves during focusing, and a control unit, The control unit an acquisition unit that acquires reference position information of the first lens group using characteristic information indicating a relationship between a defocus amount of the lens device and a subject distance when the first operation unit is operated; and a determination unit that determines a target position of the first lens group by using the characteristic information and the reference position information when the second operation unit is operated, the reference position information is information about a position of the first lens group in a second state in which a movable range of the first lens group is wider than that of the first state of the lens device when the first operating means is operated, The lens device is characterized in that the second state is a state in which the amount of aberration of the lens device is larger than that of the first state.

7. 7. The lens device according to claim 6, further comprising a second lens group that moves during zooming.

8. 8. The lens device according to claim 6, further comprising an aberration changing means for changing the amount of aberration.

9. A lens device having first and second operating means, a first lens group that moves during focusing, an aberration changing means that changes the amount of aberration, and a control unit, The control unit an acquisition unit that acquires reference position information of the first lens group using characteristic information indicating a relationship between a defocus amount of the lens device and a subject distance when the first operation unit is operated; and a determination unit that determines a target position of the first lens group by using the characteristic information and the reference position information when the second operation unit is operated, The lens device is characterized in that the reference position information is information about the position of the first lens group in a second state in which the range of motion of the first lens group is wider than in a first state of the lens device when the first operating means is operated.

10. 10. The lens device according to claim 7, further comprising a third lens group that moves independently of the first lens group during focusing.

11. 11. The lens apparatus according to claim 10, wherein the reference position information is information relating to positions of the first and third lens groups in the second state.

12. 12. The lens device according to claim 7, wherein the lens device is detachable from an imaging device.

13. 1. A control method for controlling a lens apparatus having first and second operating means and a lens group that moves during focusing, comprising: acquiring reference position information of the lens group using characteristic information indicating a relationship between a defocus amount of the lens device and a subject distance when the first operation means is operated; determining a target position of the lens group using the characteristic information and the reference position information when the second operation means is operated, the reference position information is information about a position of the lens group in a second state in which a movable range of the lens group is wider than that of the first state of the lens device when the first operation means is operated, The control method according to claim 1, wherein the second state is a state in which the amount of aberration of the lens device is greater than that of the first state.

14. A program causing a computer to execute the control method according to claim 13.

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