Control device, lens device, and imaging device

Abstract

To improve operability in an imaging system that electrically drives multiple lens groups. [Solution] A control device used in an imaging system comprising an imaging device 200 and a lens device 100, wherein the lens device 100 includes a first lens group and a plurality of lens groups that move during zooming, and user-operable operating members 106 and 202, the control device has control units 109 and 203 that control the movement of the plurality of lens groups according to a first amount of operation on the operating members 106 and 202, the control units 109 and 203 switch between first control and second control based on information regarding the state of the imaging device 200, and make the maximum speed of movement of the first lens group in the first control according to the first amount of operation smaller than the maximum speed of movement of the first lens group in the second control according to the first amount of operation.

Description

Technical Field

[0001] The disclosure of this specification relates to zoom tracking control in an imaging system.

Background Art

[0002] In the control of an imaging system, zoom tracking control is known in which each of a plurality of lens groups is driven electrically to reduce fluctuations in the focus position during zooming.

[0003] The zoom tracking control in Patent Document 1 reduces fluctuations in the focus position during zooming by adjusting the driving speed of other lens groups in accordance with the moving time of the lens group with the longest moving time among the plurality of lens groups when zooming.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the control method of Patent Document 1, since the driving of other lens groups is controlled in accordance with the moving time of the lens group with the longest moving time, the responsiveness of the magnification change to the zooming operation by the user decreases. As a result, there is a possibility that the user may feel that the operability is low.

Means for Solving the Problems

[0006] A control device according to one embodiment of the present invention is a control device used in an imaging system comprising an imaging device and a lens device, wherein the lens device includes a plurality of lens groups that move during zooming, including a first lens group, and an operating member that can be operated by a user, and the control device has a control unit that controls the movement of the plurality of lens groups according to a first amount of operation on the operating member, and the control unit switches between a first control and a second control based on information regarding the state of the imaging device, and is characterized in that the maximum speed during the movement of the first lens group in the first control according to the first amount of operation is made smaller than the maximum speed during the movement of the first lens group in the second control according to the first amount of operation.

[0007] A control device according to one embodiment of the present invention is a control device used in an imaging system comprising an imaging device and a lens device, wherein the lens device includes a plurality of lens groups that move during zooming, including a first lens group, and an operating member that allows a user to perform a first operation to specify the speed of movement of the first lens group and a second operation to specify the amount of drive or target position of the first lens group, and the control device has a control unit that controls the movement of the plurality of lens groups in response to the operation of the operating member, wherein the control unit performs a first control in response to the first operation and a second control in response to the second operation, and is characterized in that the maximum speed of movement of the first lens group in the first control is made smaller than the maximum speed of movement of the first lens group in the second control. [Effects of the Invention]

[0008] According to the present invention, operability can be improved in an imaging system that electrically drives multiple lens groups. [Brief explanation of the drawing]

[0009] [Figure 1] This is a block diagram showing the configuration of the camera system in Example 1. [Figure 2] This figure shows examples of operating members in each embodiment. [Figure 3] This figure shows the control position relative to the focal length for each shooting distance in Example 1. [Figure 4] This is a flowchart showing the zooming control method in each embodiment. [Figure 5] This is a flowchart of the control that prioritizes reducing focus fluctuations during zooming in Example 1. [Figure 6] This is a flowchart of the control that prioritizes responsiveness of zoom magnification changes during zooming in Example 1. [Figure 7] This figure shows an example of how each lens is driven by a control system that prioritizes reducing focus fluctuations during zooming in Example 1. [Figure 8] This figure shows an example of how each lens is driven by a control system that prioritizes responsiveness to zoom magnification changes during zooming in Example 1. [Figure 9] This is a block diagram showing the configuration of the imaging system in Example 2. [Figure 10] This figure shows the control position relative to the focal length for each shooting distance in Example 2. [Figure 11] This figure shows the information regarding the contribution rate of the field of view change in Example 2. [Figure 12] This is a flowchart of the control that prioritizes reducing focus fluctuations during zooming in Example 2. [Figure 13] This is a flowchart of the control that prioritizes responsiveness of zoom magnification changes during zooming in Example 2. [Figure 14] This figure shows an example of how each lens is driven by a control system that prioritizes reducing focus fluctuations during zooming in Example 2. [Figure 15] This figure shows an example of driving with control that prioritizes responsiveness of zoom magnification changes during zooming in Example 2. [Modes for carrying out the invention]

[0010] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that each drawing may be drawn at a scale different from the actual for convenience. Also, as shown in each drawing, the same members are denoted by the same reference numerals, and redundant descriptions are omitted. Note that the following embodiments do not limit the invention according to the claims. Although a plurality of features are described in the embodiments, not all of these plurality of features are essential for the invention, and the plurality of features may be arbitrarily combined.

Example

[0011] Hereinafter, Example 1 will be described with reference to FIGS. 1 to 8.

[0012] FIG. 1 is a block diagram showing the configuration of the imaging system 10 in the present embodiment. The imaging system 10 in the present embodiment shows an example of a camera system in which the lens device 100 and the camera device (imaging device) 200 are detachable, but is not limited thereto, and may be an integrated lens camera.

[0013] The lens device 100 causes the light beam that has passed through the optical member 101 to enter the imaging element 201. The optical member 101 includes a first lens group 102, a second lens group 103, and an aperture 104. The intervals between the respective adjacent lens groups change during zooming or focusing in the first lens group 102 and the second lens group 103. The aperture 104 restricts the light beam incident on the imaging element 201.

[0014] Note that the lens group in each embodiment may be composed of one lens or a plurality of lenses. In the present embodiment, an example of controlling the driving of two lens groups during zooming and focusing is shown, but a configuration for controlling the driving of three or more lens groups may also be used.

[0015] The camera device 200 acquires still images and video data based on the light beam incident on the image sensor 201. The camera operation unit 202 (operating member) receives operations from the user and records still images and videos. The camera control unit 203 determines the data to be transmitted to the lens device 100 according to the operations input to the camera operation unit 202 and transmits it to the camera communication unit 204 via communication. It also controls the shutter (not shown) and other components to perform the necessary controls for imaging.

[0016] The camera communication unit 204 communicates with the lens communication unit 105 and transmits information regarding the status of the camera device, such as AF (AutoFocus) operation, still image / video mode selection operation, still image capture (shutter half-press, fully press), and video capture (recording start, stop) operation, to the lens. The lens communication unit 105 communicates with the camera communication unit 204 and transmits the received information regarding the status of the camera device to the lens control unit 109.

[0017] Furthermore, the camera communication unit 204 and the lens communication unit 105 may communicate various information necessary for imaging. For example, information such as the position of the lens and information on the optical characteristics of the lens.

[0018] The lens operation unit 106 is an operating member that can be operated by the user. Zooming can be performed by operating the lens operation unit 106 in this embodiment. When the user performs an operation for zooming, the operation instruction is transmitted to the operation input unit 107. The operation instruction includes information on whether or not the lens operation unit 106 has been operated and the amount of operation performed on the lens operation unit 106. While this embodiment shows an example of a lens device 10 having an operating member, the camera or external controller may also be configured to have an operating member.

[0019] The operation input unit 107 determines the operation command value and operation mode based on the received operation instruction and transmits them to the lens control unit 109. The method for determining the operation command value may be determined by a predetermined priority order for each operating member, or by a method set by the user. Alternatively, priority may be given to the last operated operating member, or multiple operation command values ​​may be combined to generate the value.

[0020] Memory 108 is a non-volatile memory such as flash ROM, and stores the position information of the first lens group 102 and the second lens group 103, which are in focus at each shooting distance for each focal length. Details of the control position information (tracking data) stored in memory 108 will be described later.

[0021] The lens control unit 109 determines a control method for multiple lens groups based on the transmitted information regarding the state of the camera device and the operation mode. It also controls the driving of the multiple lens groups according to the transmitted operation command value and the determined control method.

[0022] The lens drive unit 110 is an ultrasonic motor, a stepping motor, or the like, and drives the first lens group 102 and the second lens group 103 based on control by the lens control unit 109. Since the first lens group 102 and the second lens group 103 are driven individually, each of the first lens group 102 and the second lens group 103 may have its own separate drive unit. Furthermore, each drive unit may be an actuator of a different type (for example, one being an ultrasonic motor and the other a stepping motor). In addition, the maximum power used to drive each lens group may be a predetermined fixed value, or it may be variable according to the control method determined by the lens control unit 109.

[0023] The lens position detection unit 111 is composed of position detection sensors such as encoders and potentiometers, and detects the positions of the first lens group 102 and the second lens group 103 and transmits this information to the lens control unit 109. Since the first lens group 102 and the second lens group 103 are driven individually, it is preferable that each of the first lens group 102 and the second lens group 103 be provided with its own detection unit. Furthermore, each detection unit may be made of a different type of position detection sensor. For example, one position detection sensor may be an encoder and the other a potentiometer. In addition, if the drive unit is a stepping motor, open control may be performed without using position detection sensors.

[0024] Figure 2 shows an example of the lens operating unit 106 (operating member) in this embodiment. Figure 2(a) is an example of an operating member that specifies the zoom drive direction and zoom speed, and Figure 2(b) is an example of an operating member that specifies the zoom movement amount (drive amount) or zoom movement position (target position).

[0025] In Figure 2(a), for example, the rotating operating member is ring-shaped. When rotated clockwise, it instructs the unit to drive towards the TELE side, and when rotated counterclockwise, it instructs the unit to drive towards the WIDE side. Furthermore, the greater the amount of rotation, the faster the optical element is driven, and at a predetermined position (the 12 o'clock position in Figure 2(a)), it is possible to instruct the unit to either not drive the optical element or to stop it. The operating member may also be configured to automatically return to the predetermined position when not being operated. The operating member in Figure 2(a) is an operating member that specifies the zoom drive direction and zoom speed. Therefore, it can be used, for example, for PZ (power zoom) operation.

[0026] In Figure 2(b), for example, the operating member is a ring-shaped rotating operating member, and the focal length can be specified according to the position of the rotation. Alternatively, it may be configured so that the zoom movement amount can be specified according to the direction and amount of rotation. The operating member in Figure 2(b) does not allow for the specification of zoom speed, but rather specifies the zoom movement amount or zoom movement position. Therefore, it can be used, for example, for MZ (manual zoom).

[0027] Note that the operating member shown in Figure 2 is just an example and is not limited to it. The operating member in this embodiment may be configured to be switched by sliding a ring, or the same operating member may be configured to be switched by a slide switch or the like. Alternatively, multiple operating members may be configured in different locations, and the operation of the last operating member to be operated may be adopted.

[0028] Figure 3 shows the control position of the lens group with respect to focal length for each shooting distance. Figure 3 shows the zoom tracking curves of each lens group when the subject distance is 0.5m, 5.0m, 10m, and ∞ (infinity). In Figure 3, the horizontal axis is focal length, and the vertical axis is the control position of each lens group. Figures 3(a) and 3(b) show the tracking data for the first lens group 102 and the second lens group 103, respectively.

[0029] In this embodiment, the first lens group 102 and the second lens group 103 are lens groups that are driven by both zooming to change the focal length and focusing to change the shooting distance, and the drive trajectory when changing the focal length differs for each shooting distance. Furthermore, in this embodiment, the first lens group 102 is mainly responsible for changing the angle of view, and the second lens group 103 is mainly responsible for changing the shooting distance.

[0030] Here, lens groups responsible for changing the angle of view have high zoom sensitivity, while lens groups responsible for changing the shooting distance have high focus sensitivity. The zoom sensitivity of each lens group can be expressed by the amount of change in the angle of view of the optical system in relation to the amount of movement of the lens group, and the focus sensitivity of each lens group can be expressed by the amount of change in the focus position of the optical system in relation to the amount of movement of the lens group.

[0031] Figure 4 is a flowchart showing the control method of the lens control unit 109 when zooming.

[0032] In step S101, the user operates the lens operation unit 106, and the operation type input to the lens control unit 109 is determined. In this embodiment, the lens control unit 109 determines whether the operation includes specifying the speed of movement of the lens group that moves during zooming (zoom speed) (first operation) or does not include specifying the zoom speed (second operation). If the operation specifies the zoom speed, the process proceeds to step S103; otherwise, the process proceeds to step S102.

[0033] The first operation is a PZ operation, and the second operation is an MZ operation. The lens operation unit 106 in this embodiment is configured to allow the user to perform both PZ and MZ operations, and may be composed of multiple operating members, for example. Alternatively, it may be configured so that the PZ operation and MZ operation can be arbitrarily switched using a single operating member such as a switch. Furthermore, the operating member may be included in the camera device 200. In addition, in the imaging system, the operating member of an operating device (not shown) that can communicate with at least one of the lens device 100 and the camera device 200 may be configured to be operable by the user.

[0034] In step S102, if the camera device is in the process of capturing an image, the process proceeds to step S103; otherwise, the process proceeds to step S104. In this embodiment, capturing an image means that the shutter is fully pressed, or that recording is in progress in video recording mode.

[0035] In step S102, if the camera device is in the state of preparing to take an image, the process may proceed to step S103. In this embodiment, "preparing to take an image" refers to states such as when the shutter is half-pressed by the user or when the camera's AF (autofocus) is operating.

[0036] In step S103, the drive of multiple lens groups is controlled (first control) with priority given to reducing focus shift during zooming. In step S104, the drive of multiple lens groups is controlled (second control) with priority given to rapidly changing the zoom magnification. Details of steps S103 and S104 in this embodiment will be described later.

[0037] In this embodiment, the steps in Figure 4 are described as being performed by the lens control unit 109, but this embodiment is not limited thereto. For example, some or all of the steps of the process shown in Figure 4 may be performed by the camera control unit 203. Furthermore, the imaging system may be configured to perform the steps in Figure 4 by a device (not shown) that can communicate with at least one of the lens device 100 and the camera device 200.

[0038] In the following, control means capable of executing the processing of each step in Figure 4 (lens control unit 109, camera control unit 203, and control unit of an unillustrated device) will be referred to as a control unit. Furthermore, a device having a control unit (lens device 100, camera device 200, and an unillustrated device) will be referred to as a control device.

[0039] In this embodiment, an example of control based on both the operating mode and the state of the camera device has been described, but the invention is not limited to this, and control may be performed based on either one of them.

[0040] When switching control based solely on the operation type, it is preferable that operations that do not specify a zoom speed (second operation) are controlled to prioritize rapid zoom magnification changes over operations that specify a zoom speed (first operation). This is because operations that do not specify a zoom speed, such as MZ operations, are operations in which the user directly specifies the zoom amount or zoom position. Therefore, by providing control that quickly drives zoom magnification changes in response to the specification, it is possible to provide control with high usability.

[0041] Furthermore, when switching control based solely on information regarding the camera device's status, the first and second controls may be switched depending on whether it is in still image shooting mode or video shooting mode. In this case, it is preferable that the control prioritizes reducing focus shift when in video shooting mode. This is because, in video shooting mode, if the user wants to zoom while maintaining focus on the subject during imaging, prioritizing the reduction of focus shift provides a control with high usability.

[0042] This embodiment is not limited to this, nor is the control method according to the state limited to this. Furthermore, the control method according to the state may be configured to be changeable by the user. Moreover, the control method according to the state does not need to reduce the speed over the entire range of movement of the lens group. Specifically, in the case of Figure 3, the control method according to the state may be configured to be performed only in the TELE side region (a predetermined focal length) where focus shifts are particularly likely to occur. Similarly, the control method according to the state may be configured to be performed only at a predetermined focal length shooting distance.

[0043] Here, with reference to Figure 5, an example of a control method (first control) prioritizing the reduction of focus shift during zooming in step S103 will be described. In this embodiment, the processing in step S103 is performed continuously until the zoom magnification change is completed within a predetermined control cycle.

[0044] In step S201, the lens control unit 109 calculates the zoom amount and zoom speed of the first lens group 102 within a predetermined time based on the operation command value. For example, if the operation includes specifying the zoom speed, it calculates the zoom amount that can be moved within a predetermined time at the specified zoom speed. Alternatively, if the operation specifies the zoom position or zoom amount, it calculates the zoom amount that can be moved within a predetermined time at the maximum speed. However, if the specified zoom position is reached within the predetermined time, the zoom amount is set to the zoom amount to the final target position.

[0045] In step S202, the lens control unit 109 calculates the zoom position of the first lens group 102 after a predetermined time from the zoom movement amount of the first lens group 102 calculated in step S201. Furthermore, by referring to the tracking data for each lens group stored in the memory 108, it calculates the zoom position of the second lens group 103 so that it has the same focal length and shooting distance as the zoom position of the first lens group 102 after a predetermined time.

[0046] Next, the zoom amount and zoom speed of the second lens group 103 are determined so that it moves to the calculated zoom position after a predetermined time. However, if this exceeds the maximum speed at which the second lens group 103 can be driven, the zoom speed is set to the maximum speed, and the zoom amount is also set to a zoom amount that can be achieved within the predetermined time.

[0047] In step S203, the lens control unit 109 determines whether the zoom speed of the second lens group 103 calculated in step S202 is the maximum speed. If it is the maximum speed, the unit proceeds to step S204; otherwise, it terminates.

[0048] In step S204, the lens control unit 109 calculates the zoom position of the second lens group 103 after a predetermined time based on the zoom movement amount of the second lens group 103 calculated in step S202. Furthermore, by referring to the control position data for each lens group stored in the memory 108, it calculates the zoom position of the first lens group 102 so that it has the same focal length and shooting distance as the zoom position of the second lens group 103 after a predetermined time. Subsequently, the zoom movement amount and zoom speed of the first lens group 102 are recalculated so that it moves to the calculated zoom position after a predetermined time.

[0049] Here, with reference to Figure 6, an example of a control method (second control) that prioritizes rapid zoom magnification change in step S104 will be described. In this embodiment, the processing in step S104 is performed continuously until the zoom magnification change is completed within a predetermined control cycle.

[0050] Steps S301 and S302 are the same as steps S201 and S202 in Figure 5.

[0051] In step S303, the amount of synchronization misalignment is calculated based on the positions of the first lens group 102 and the second lens group 103 after a predetermined time. The amount of synchronization misalignment is calculated based on how much the positions of the first lens group 102 and the second lens group 103 after a predetermined time deviate from the positional relationship (synchronization position) of the first lens group 10 and the second lens group 103 in the tracking data.

[0052] In step S304, it is determined whether the synchronization misalignment amount calculated in step S303 exceeds the allowable value. If it exceeds the allowable value, the process proceeds to step S305; otherwise, the process terminates.

[0053] In this embodiment, the tolerance value may be set such that, for example, when the movable ranges of the first lens group 102 and the second lens group 103 overlap, the first lens group 102 and the second lens group 103 do not collide. Alternatively, it may be set so that the amount of focus shift is within an acceptable range so that the subject is not lost during autofocus, etc. Note that setting a tolerance value is not mandatory, and if no tolerance value is set, this step may be omitted.

[0054] In step S305, the zoom movement amount and zoom speed of the first lens group 102 are recalculated based on the position of the second lens group 103 after a predetermined time and the allowable value of the synchronization misalignment, so that the synchronization misalignment falls within the allowable value.

[0055] In this embodiment, the control unit can switch between the first control and the second control depending on the situation, for example, when accuracy of the focus position during angle of view changes in zooming is required, or when responsiveness of angle of view changes to user operation is required. Furthermore, the maximum speed of movement of the first lens group in the first control is set to be smaller than the maximum speed of movement of the first lens group in the second control.

[0056] With this configuration, the control in step S103 (first control) prioritizes reducing focus shift during zooming over the control in step S104 (second control). On the other hand, the control in step S104 (second control) prioritizes responsiveness to zoom magnification changes over the control in step S103 (first control). As a result, operability can be improved in imaging systems that electrically drive multiple lens groups.

[0057] The first lens whose maximum speed is adjusted by the control unit is preferably the lens with the fastest speed among the lens group that moves during zooming. Alternatively, it is preferably the lens group with the highest zoom sensitivity among the lens group that moves during zooming. With such a configuration, the responsiveness of the change in magnification to the user's zooming operation can be suitably adjusted.

[0058] In this embodiment, the control unit has been described as adjusting the maximum speed of the lens group, but it may also control the acceleration during zooming in a similar manner. The control unit also adjusts the movement speed and acceleration of the lens group by varying the control signals transmitted to the drive unit. The control unit may also adjust the maximum speed of the lens group by changing the power used or available power to drive each lens group that is sent to each lens group.

[0059] In this embodiment, the maximum speed of the lens group (first lens) that moves during zooming is smaller in the first control than in the second control, assuming the user's input is the same. In other words, the control unit makes the maximum speed of the first lens group's movement in the first control smaller than the maximum speed of the first lens group's movement in the second control.

[0060] This configuration improves user operability in imaging systems that electrically drive multiple lens groups.

[0061] Next, with reference to Figure 7, an example of a control method (first control) prioritizing the reduction of focus shift during zooming in step S103 of this embodiment will be described. Figure 7 illustrates the situation when the zoom magnification is changed from focal length A to B by zoom operation at a subject distance of 5.0m. In Figure 7, the horizontal axis represents the focal length, and the vertical axis represents the control position of each lens group.

[0062] Figure 7(a) shows an example of driving the first lens group 102, and Figure 7(b) shows an example of driving the second lens group 103. In Figure 7, t0, t1, and t2 indicate the control positions of the first lens group 102 and the second lens group 103 for each control cycle, respectively.

[0063] In the example in Figure 7, the zoom movement of the first lens group 102 is less than that of the second lens group 103, and if the first lens group 102 is moved at maximum speed, it can be driven to a position corresponding to focal length B at time t1. However, even if the second lens group 103 is moved at maximum speed, it can only move to an intermediate position between focal lengths A and B at time t1. Therefore, the zoom speed of the first lens group 102 is limited to match that of the second lens group 103, and the zoom movement amount is determined so that it is at an intermediate position between focal lengths A and B at time t1. Subsequently, at time t2, the second lens group 103 can move to the position of focal length B, so the first lens group 102 also moves to the position of focal length B.

[0064] In this example, we described a case where the zoom movement differs for multiple lens groups, but the same processing can be applied even when differences occur in maximum zoom speed and maximum acceleration due to actuator performance, power consumption ratio, lens group weight, etc. For example, it is also effective when the maximum zoom speed and maximum acceleration of the second lens group 103 are smaller than those of the first lens group 102.

[0065] Next, with reference to Figure 8, an example of a control method (second control) that prioritizes rapid zoom magnification change in step S104 according to this embodiment will be described. The representation in the figure is the same as in Figure 7.

[0066] In this control method, the zoom speed of the first lens group 102 is not limited, and the first lens group 102 is moved to the position of focal length B at time t1. At time t1, the second lens group 103 can only move to an intermediate position between focal lengths A and B, so the focus position is temporarily shifted. However, since the change in angle of view mainly depends on the position of the first lens group 102, the zoom magnification can be changed faster than in the control method described in Figure 7.

[0067] As described above, this embodiment is configured to switch between a control that changes the zoom magnification while reducing focus shift during zooming, and a control that speeds up the response of zoom magnification changes, depending on the state and operation mode of the camera device. As a result, for example, when operating in a manner that zooms to the angle of view corresponding to the ring operation position in order to determine the composition before recording, the response to the operation is sped up, improving convenience. [Examples]

[0068] Example 2 will be described below with reference to Figures 9 to 15.

[0069] In this embodiment, when the drive of multiple lens groups is controlled individually during zooming, an example is described in which the delay in changing the zoom magnification caused by the drive delay of one lens group is mitigated by the drive of another lens group.

[0070] Figure 9 is a block diagram showing the configuration of the imaging system 20 in this embodiment. The imaging system 20 in Embodiment 2 differs from that in Embodiment 1 in that, in addition to the first lens group 102 and the second lens group 103, it also has a third lens group 112.

[0071] The first lens group 102, the second lens group 103, and the third lens group 112 have a change in the spacing between adjacent lens groups during zooming or focusing. In each embodiment, the lens group may consist of one lens or multiple lenses.

[0072] In this embodiment, memory 108 can store tracking data for the first lens group 102, the second lens group 103, and the third lens group 112. It may also store data on the contribution rate of the third lens group 112 to the first lens group 102 in changing the field of view. Details of the data stored in memory 108 will be described later.

[0073] Furthermore, in this embodiment, the lens control unit 109 calculates drive information for the third lens group 112 in addition to drive information for the first lens group 102 and the second lens group 103. The lens drive unit 110 and the lens position detection unit 111 are configured to include a drive unit that drives the third lens group 112 and a position detection sensor that detects the position of the third lens group 112.

[0074] Figure 10 shows the control position of the lens group with respect to focal length for each shooting distance. Figure 10 shows the zoom tracking curves of each lens group when the subject distance is 0.5m, 5.0m, 10m, and ∞ (infinity). In Figure 10, the horizontal axis is focal length, and the vertical axis is the control position of each lens group. Figures 10(a), 10(b), and 10(C) show the tracking data for the first lens group 102, the second lens group 103, and the third lens group 112, respectively.

[0075] In this embodiment, the first lens group 102, the second lens group 103, and the third lens group 112 are lens groups that are driven by both zooming to change the focal length and focusing to change the shooting distance, and the drive trajectory when changing the focal length differs for each shooting distance. In addition, in this embodiment, the first lens group 102 and the third lens group 112 are lens groups that have high zoom sensitivity and mainly play a role in changing the angle of view, while the second lens group 103 is a lens group that has high focus sensitivity and mainly plays a role in changing the shooting distance.

[0076] Figure 11 shows an example of the angle of view change contribution rate of multiple lens groups in this embodiment. In this embodiment, memory 108 stores the ratio of how much the third lens group 112 contributes to the angle of view change relative to the first lens group 102. In other words, in the control method described above, by using the angle of view change contribution rate, it is possible to calculate the amount of zoom movement of the first lens group 102 required to change the angle of view by the same amount as the angle of view change that occurs when the third lens group 112 moves by a predetermined amount. In this embodiment, an example is shown where the angle of view change contribution rate changes depending only on the focal length, but the memory 108 is not limited to this, and may store angle of view change contribution rate data for each focal length and each shooting distance.

[0077] Here, with reference to Figure 12, an example of a control method prioritizing the reduction of focus shift during zooming in step S103 according to this embodiment will be described. The processing in step S103 in this embodiment is performed continuously until the zoom magnification change is completed within a predetermined control cycle.

[0078] In step S401, the lens control unit 109 calculates the range of focal lengths in which the first lens group 102, the second lens group 103, and the third lens group 112 can move while maintaining the shooting distance within a predetermined time, based on the tracking data stored in the memory 108. However, in this embodiment, the lens control unit 109 limits this range to one that does not exceed the focal length of the final target position based on the zoom operation instruction.

[0079] In step S402, the lens control unit 109 calculates the zoom movement amount and zoom speed of all lens groups so that they move to a position that maintains the shooting distance at the closest focal length among the focal lengths calculated in step S401. In other words, in the control method described above, the zoom speed of one of the lens groups is referenced to limit the zoom speed of the other lens groups so that focus shifts are less likely to occur when changing the focal length for multiple lens groups.

[0080] Next, with reference to Figure 13, an example of a control method prioritizing rapid zoom magnification change in step S104 according to this embodiment will be described. In this embodiment, the processing in step S104 is performed continuously until the zoom magnification change is completed within a predetermined control cycle.

[0081] In step S501, the lens control unit 109 calculates the zoom movement amount and zoom speed of the third lens group 112 in a predetermined time based on the input operation command value.

[0082] In step S502, the zoom position of the third lens group 112 after a predetermined time is calculated based on the zoom movement amount calculated in step S501, and the remaining drive amount for the input operation command value is calculated.

[0083] In step S503, the lens control unit 109 calculates the zoom movement amount and zoom speed of the first lens group 102 to correct the remaining drive amount of the third lens group 112, based on the remaining drive amount calculated in step S502 and the angle of view change contribution rate of the third lens group 112. However, in this embodiment, if the zoom speed of the first lens group 102 exceeds the maximum zoom speed, the lens control unit 109 limits the zoom movement amount to the amount that can be moved within a predetermined time at the maximum zoom speed.

[0084] In step S504, the lens control unit 109 calculates the focal length after a predetermined time based on the zoom position of the first lens group 102 and the third lens group 112 after a predetermined time, the tracking data for each lens group, and the angle of view change contribution rate. Subsequently, the lens control unit 109 calculates the zoom position of the second lens group 103 to maintain the shooting distance at the focal length calculated using the tracking data.

[0085] Then, the zoom amount and zoom speed of the second lens group 103 are determined so that it moves to that position after a predetermined time. However, in this embodiment, if the zoom speed exceeds the maximum speed at which the second lens group 103 can be driven, the lens control unit 109 limits the zoom speed to the maximum speed and also limits the zoom amount to the amount that can be moved within the predetermined time.

[0086] In other words, the control method described above controls the driving of multiple lens groups by referencing the drive delay information of one of the lens groups, so as to mitigate the delay in changing the angle of view caused by the drive delay in the other lenses. With this configuration, the zoom magnification can be changed faster than with the control method described in Figure 12.

[0087] Here, with reference to Figure 14, an example of a control method (first control) prioritizing the reduction of focus shift during zooming in step S103 according to this embodiment will be described. Figure 14 shows an example in which the zoom magnification is changed from focal length A to B by zoom operation at a subject distance of 5.0m.

[0088] Figures 14(a), 14(b), and 14(c) show examples of driving the first lens group 102, the second lens group 103, and the third lens group 112, respectively. In Figure 14, t0, t1, and t2 indicate the control positions of the first lens group 102, the second lens group 103, and the third lens group 112 for each control cycle, respectively.

[0089] In the example in Figure 14, the second lens group 103 has the largest zoom movement, and even when the second lens group 103 is moved at maximum speed, it can only move to an intermediate position between focal lengths A and B at time t1. Therefore, the zoom speed of the first lens group 102 and the third lens group 112 is limited to match that of the second lens group 103, and the zoom movement is determined so that at time t1 it is at an intermediate position between focal lengths A and B. Subsequently, at time t2, the second lens group 103 can move to the position of focal length B, so the first lens group 102 and the third lens group 112 also move to the position of focal length B.

[0090] Referring to Figure 15, an example of a control method (second control) that prioritizes rapid zoom magnification change in step S104 according to this embodiment will be described.

[0091] In the example shown in Figure 15, the zoom speed of the third lens group 112 is not restricted, and it moves at its maximum zoom speed. In this example, the third lens group 112 can move to the position of focal length A' at time t1.

[0092] At time t1, the third lens group 112 is at focal length A', which causes a delay (remaining drive) in changing the angle of view until the specified focal length B is reached by the zoom operation.

[0093] Therefore, based on the data on the contribution rate of angle of view change, the first lens group 102 is controlled to be driven to the position of focal length B' at time t1, so as to compensate for the delay in angle of view change by the remaining drive amount of the third lens group 112 using the first lens group 102.

[0094] Since the angle of view changes mainly depend on the positions of the first lens group 102 and the third lens group 112, reducing the drive delay of the third lens group 112 with the first lens group 102 results in the focal length at time t1 being approximately at position B.

[0095] Therefore, by moving the second lens group 103 to the position of focal length B at time t1, the shift in the focus position can be reduced. However, even when the second lens group 103 is moved at maximum speed, it can only move to an intermediate position between focal lengths A and B. For this reason, the second lens group 103 is controlled to move to an intermediate position between focal lengths A and B at time t1.

[0096] At time t2, all lens groups are capable of being driven to focal length B, so the system is controlled to drive all lens groups to focal length B.

[0097] In this embodiment, the drive of multiple lens groups is controlled by referring to the remaining drive information of one of the lens groups to mitigate the delay in changing the angle of view of the other lenses.

[0098] This configuration mitigates the delay in changing the angle of view caused by the drive delay of any of the multiple lens groups, allowing for quick changes in zoom magnification.

[0099] As a result, operability can be improved in imaging systems that electrically drive multiple lens groups.

[0100] Although preferred embodiments and examples of the present invention have been described above, the present invention is not limited to these embodiments and examples, and various combinations, modifications, and changes are possible within the scope of its gist.

[0101] Embodiments of the present invention include the following configurations.

[0102] (Composition 1) A control device used in an imaging system comprising an imaging device and a lens device, The lens device includes a first lens group and a plurality of lens groups that move during zooming, and an operating member that can be operated by the user. The control device has a control unit that controls the movement of the plurality of lens groups according to a first amount of operation on the operating member, The control unit, Based on information regarding the state of the imaging device, the first control and the second control are switched. A control device characterized in that the maximum speed during the movement of the first lens group in the first control according to the first operation amount is made smaller than the maximum speed during the movement of the first lens group in the second control according to the first operation amount.

[0103] (Configuration 2) A control device used in an imaging system comprising an imaging device and a lens device, The lens device includes a first lens group and a plurality of lens groups that move during zooming, and an operating member that allows the user to perform a first operation to specify the speed of movement of the first lens group and a second operation to specify the amount of drive or target position of the first lens group. The control device has a control unit that controls the movement of the plurality of lens groups in response to an operation on the operating member, The control unit, The first control is performed in response to the first operation, and the second control is performed in response to the second operation. A control device characterized in that the maximum speed during the movement of the first lens group in the first control is made smaller than the maximum speed during the movement of the first lens group in the second control.

[0104] (Composition 3) The control device according to configuration 1, characterized in that the control unit performs the first control when the state is imaging and performs the second control when the state is not imaging.

[0105] (Composition 4) The control device according to configuration 1, characterized in that the control unit performs the first control when the state is such that the shutter is half-pressed by the user or the autofocus is in operation by the imaging device.

[0106] (Composition 5) The control device according to configuration 1, characterized in that the control unit performs the first control when the state is in video recording mode, and performs the second control when the state is in still image recording mode.

[0107] (Composition 6) The control device according to any one of configurations 1 to 5, characterized in that the first lens group is the lens group with the highest zoom sensitivity among the plurality of lens groups.

[0108] (Composition 7) The control device according to any one of configurations 1 to 6, characterized in that the control unit makes the power available for driving the plurality of lens groups in the first control less than the power available for driving the plurality of lens groups in the second control.

[0109] (Composition 8) The control device according to any one of configurations 1 to 7, characterized in that the control unit controls the amount of movement or the position of a lens group different from the lens group based on the drive delay information of one of the plurality of lens groups in the second control.

[0110] (Composition 9) A lens device including a control device described in any one of configurations 1 to 8, A lens device characterized by having the plurality of lens groups and the operating member.

[0111] (Composition 10) An imaging apparatus characterized by including a control device described in any one of configurations 1 to 8. [Explanation of Symbols]

[0112] 100 Lens device 200 Imaging device 109, 203 Control Unit 106, 202 Operating members

Claims

1. A control device used in an imaging system comprising an imaging device and a lens device, The lens device includes a first lens group and a plurality of lens groups that move during zooming, and an operating member that can be operated by the user. The control device has a control unit that controls the movement of the plurality of lens groups according to a first amount of operation on the operating member, The control unit, Based on information regarding the state of the imaging device, the first control and the second control are switched. A control device characterized in that the maximum speed during the movement of the first lens group in the first control according to the first operation amount is made smaller than the maximum speed during the movement of the first lens group in the second control according to the first operation amount.

2. A control device used in an imaging system comprising an imaging device and a lens device, The lens device includes a first lens group and a plurality of lens groups that move during zooming, and an operating member that allows the user to perform a first operation to specify the speed of movement of the first lens group and a second operation to specify the amount of drive or target position of the first lens group. The control device has a control unit that controls the movement of the plurality of lens groups in response to an operation on the operating member, The control unit, A first control is performed in response to the first operation, and a second control is performed in response to the second operation. A control device characterized in that the maximum speed during the movement of the first lens group in the first control is made smaller than the maximum speed during the movement of the first lens group in the second control.

3. The control device according to claim 1, characterized in that the control unit performs the first control when the state is imaging and performs the second control when the state is not imaging.

4. The control device according to claim 1, characterized in that the control unit performs the first control when the state is such that the shutter is half-pressed by the user or the autofocus is in operation by the imaging device.

5. The control device according to claim 1, characterized in that the control unit performs the first control when the state is in video recording mode, and performs the second control when the state is in still image recording mode.

6. The control device according to any one of claims 1 to 5, characterized in that the first lens group is the lens group with the highest zoom sensitivity among the plurality of lens groups.

7. The control device according to any one of claims 1 to 5, characterized in that the control unit reduces the power available for driving the plurality of lens groups in the first control to less than the power available for driving the plurality of lens groups in the second control.

8. The control device according to any one of claims 1 to 5, characterized in that the control unit controls the amount of movement or the position of a lens group different from the lens group based on the drive delay information of one of the plurality of lens groups in the second control.

9. A lens device comprising a control device according to any one of claims 1 to 5, A lens device characterized by having the plurality of lens groups and the operating member.

10. An imaging apparatus characterized by including the control device described in any one of claims 1 to 5.

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