Lens device and control method of the same

Abstract

To appropriately supply electric power to a plurality of optical elements to be simultaneously driven.SOLUTION: A lens device 100 includes a first optical element 104 and a second optical element 125, and can adjust focal distance. The lens device comprises: first driving means 108 for driving the first optical element; second driving means 126 for driving the second optical element; power supply means 128 for supplying electric power to the first and second driving means; and control means 112 for controlling the supply of electric power. The control means acquires information on the focal distance, and when supplying electric power to both the first driving means and the second driving means, changes a first upper limit of the electric power supplied to the first driving means and a second upper limit of the electric power supplied to the second driving means in accordance with the information on the focal distance.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a lens device that receives power supply from an imaging device or the like.

Background Art

[0002] In a lens device (interchangeable lens) that is detachably attached to an imaging device, a plurality of optical elements such as lenses and diaphragms may be driven simultaneously. However, in a camera system in which the lens device receives power supply from the imaging device, there is a limit to the power that can be used within the lens device.

[0003] Patent Document 1 discloses a lens device that sets the power distributed to the driving of each optical element according to the driving amounts of a plurality of optical elements driven simultaneously, so that the total power (total power consumption) used in the simultaneous driving of the plurality of optical elements does not exceed a predetermined power.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the lens device of Patent Document 1 assumes that the power consumption changes depending on the driving speed (driving time) of the optical element, and does not consider the change in power consumption due to optical characteristics such as the focal length. For this reason, when simultaneously driving a plurality of optical elements in a zoom lens device whose focal length is variable, it may not be possible to distribute power to the driving of these optical elements, and there is a risk that the driving performance of each optical element will be limited.

[0006] The present invention provides a lens device capable of appropriately supplying power to a plurality of simultaneously driven optical elements.

Means for Solving the Problem

[0007] A lens device as one aspect of the present invention has a first optical element and a second optical element, and the focal length is variable. The lens device includes first driving means for driving the first optical element, second driving means for driving the second optical element, power supply means for supplying power to the first and second driving means, and control means for controlling the supply of power. The control means acquires information regarding the focal length, and when supplying power to both the first driving means and the second driving means, changes a first upper limit value for the power supplied to the first driving means and a second upper limit value for the power supplied to the second driving means according to the information regarding the focal length.

[0008] Also, a control method as another aspect of the present invention is applied to a lens device having a first optical element and a second optical element, and the focal length is variable. The control method includes a step of acquiring information regarding the focal length, and a step of changing a first upper limit value for the power supplied to the first driving means and a second upper limit value for the power supplied to the second driving means according to the information regarding the focal length when supplying power to both the first driving means for driving the first optical element and the second driving means for driving the second optical element. A program for causing a computer to execute the processing according to the above control method also constitutes another aspect of the present invention.

Advantages of the Invention

[0009] According to the present invention, it is possible to appropriately supply power to a plurality of optical elements that are simultaneously driven within the lens device.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0012] FIG. 1 shows the configuration of the communication and control system of a camera system 10 including an interchangeable lens 100 as a lens device according to an embodiment of the present invention. The camera system 10 has an interchangeable lens 100 and a camera body 200 as an imaging device to which the interchangeable lens 100 is detachably and communicably attached. Note that, instead of the lens interchangeable type camera body 200, a lens-integrated imaging device may be used.

[0013] In the interchangeable lens 100, the imaging optical system includes a fixed front lens 101, a diaphragm 103, a correction lens 104, a focus lens 105, a floating lens 121, and a zoom lens 125. Note that each lens is composed of one or a plurality of lens elements. An amount-of-light adjustment unit 116, a correction unit 117, a focus unit 118, an aberration correction unit 120, and a zoom unit 124 are provided in the interchangeable lens 100.

[0014] The amount-of-light adjustment unit 116 has a diaphragm 103, a diaphragm actuator 106, and a diaphragm drive circuit 107. The diaphragm 103 changes the aperture diameter by driving the diaphragm actuator 106 such as a stepping motor or a DC motor to adjust the amount of light. The diaphragm drive circuit 107 supplies a voltage and a current for driving the diaphragm actuator 106 to the diaphragm actuator 106.

[0015] The shake correction unit 117 includes a correction lens 104 as a first optical element, a correction actuator 108 as a first driving means, and a correction drive circuit 109. The correction lens 104 moves (shifts) with respect to the optical axis by driving the correction actuator 108 such as a stepping motor or a voice coil motor, and reduces (corrects) image blur caused by camera shake such as hand shake. The correction drive circuit 109 supplies a voltage and a current for driving the correction actuator 108 thereto.

[0016] The focus unit 118 includes a focus lens 105, a focus actuator 110, and a focus drive circuit 111. The focus lens 105 moves in the direction along the optical axis (hereinafter referred to as the optical axis direction) by driving the focus actuator 110 such as a stepping motor, a voice coil motor, and a vibration type motor to perform focusing. The focus drive circuit 111 supplies a voltage and a current for driving the focus actuator 110 thereto.

[0017] The aberration correction unit 120 includes a floating lens 121, a floating actuator 122, and a floating drive circuit 123. The floating lens 121 moves in the optical axis direction by driving the floating actuator 122 such as a stepping motor, a voice coil motor, and a vibration type motor to perform aberration correction and focusing. The floating drive circuit 123 supplies a voltage and a current for driving the floating actuator 122 thereto.

[0018] The zoom unit 124 includes a zoom lens 125 as a second optical element, a zoom actuator 126 as a second driving means, and a zoom drive circuit 127. The zoom lens 125 moves in the optical axis direction by driving the zoom actuator 126 such as a stepping motor, a voice coil motor, and a vibration type motor to perform zooming from the wide-angle end to the telephoto end. The zoom drive circuit 127 supplies a voltage and a current for driving the zoom actuator 126 thereto.

[0019] Each actuator is driven by, for example, a PWM drive method. In this case, the lens control CPU 112, which is a computer in the interchangeable lens 100, transmits a signal for specifying the duty ratio of PWM to each drive circuit, and each drive circuit drives each actuator at the duty ratio corresponding to the received signal.

[0020] When the interchangeable lens 100 is attached to the camera body 200, the communication contacts 113a, 113b, 113c provided on the interchangeable lens 100 are electrically connected to the communication contacts 207a, 207b, 207c provided on the camera body 200, respectively. Thereby, various information can be communicated between the interchangeable lens 100 and the camera body 200. FIG. 1 shows the case of performing three-wire serial communication. In this case, the lens control CPU 112 and the camera control CPU (computer) 206 in the camera body 200 perform serial communication with the camera control CPU 206 as a clock master. Note that the communication method between the interchangeable lens 100 and the camera body 200 may be other communication methods.

[0021] FIG. 2 shows the configuration of the power supply system of the camera system 10. The camera body 200 is provided with a camera power supply unit 209. The camera power supply unit 209 may be a primary battery such as an alkaline battery, a secondary battery such as a lithium ion battery, or even a power supply other than a battery.

[0022] When the interchangeable lens 100 is attached to the camera body 200, the power supply contact 129 provided on the interchangeable lens 100 and the power supply contact 210 provided on the camera body 200 are electrically connected. The camera power supply unit 209 generates a plurality of different voltages, supplies the power of the voltage required for the operation of each part of the camera body 200, or supplies the lens power to the interchangeable lens 100 (lens power supply unit 128) via the power supply contacts 210 and 129.

[0023] The lens power supply unit 128 as a power supply means generates a plurality of different voltages from the lens power received from the camera power supply unit 209, and supplies the power of the voltages necessary for the operations of various sensors, the lens control CPU 112, and each drive circuit in the interchangeable lens 100. The lens control CPU 112 as a control means controls the lens power supply unit 128 to control the power supply from the lens power supply unit 128 to each drive circuit.

[0024] The camera body 200 is provided with an imaging element 201 which is a photoelectric conversion element such as a CCD sensor or a CMOS sensor. The imaging element 201 photoelectrically converts the optical image (subject image) formed by the imaging optical system on its imaging surface. The charges accumulated in the imaging element 201 by photoelectric conversion are output as an analog imaging signal at a predetermined timing, and the analog imaging signal is input to the video signal processing circuit 202.

[0025] The video signal processing circuit 202 converts the analog imaging signal from the imaging element 201 into a digital imaging signal, performs various signal processes such as amplification and gamma correction on the digital imaging signal, and generates a video signal (image data). The video signal is output to the camera control CPU 206, a display device 205 such as a liquid crystal display panel, and a storage device 204 such as an optical disk or a semiconductor memory.

[0026] Also, an AF signal processing circuit 203 as a focus information generation unit is provided in the video signal processing circuit 202. The AF signal processing circuit 203 extracts high-frequency components and luminance components in a focus detection area (AF area) from the digital imaging signal or the video signal, and generates a focus evaluation value signal as focus information. The focus evaluation value signal indicates the contrast state (sharpness) of the video and changes as the focus lens 105 moves. The position of the focus lens 105 at which the value of the focus evaluation value signal, that is, the focus evaluation value becomes maximum (peak) is the in-focus position in that AF area.

[0027] As shown in FIG. 1, the lens control CPU 112 includes an internal storage device 114. The internal storage device 114 stores data (zoom tracking data) on the position of the focus lens 105 for obtaining a focused state with respect to the position of the zoom lens 125 and the subject distance. The internal storage device 114 also stores data regarding the power upper limit value described later.

[0028] The focal length detection unit 119 in the interchangeable lens 100 detects the positions of the zoom lens 125 and zoom drive members such as a cam ring that drives the zoom lens 125 by a position sensor, and generates information regarding the focal length from the detected positions. The information regarding the focal length may be the focal length itself of the imaging optical system, may be information convertible to the focal length, or may be information indicating the position of the zoom lens 125 or the zoom drive member or information convertible to the position. The information regarding the focal length (hereinafter referred to as focal length information) is output to the lens control CPU 112.

[0029] The lens operation unit 115 provided in the interchangeable lens 100 is provided for receiving user operations on the interchangeable lens 100. The lens operation unit 115 includes a ring member for instructing the driving of the focus lens 105 and the zoom lens 125, a switch member for switching the operation mode of the interchangeable lens 100, and the like.

[0030] The camera operation unit 208 provided in the camera body 200 is provided for receiving user operations on the camera body 200. The camera operation unit 208 includes a dial member and a button member for changing various setting values related to imaging. Information on a specific operation including an instruction to drive the zoom lens 125 among the user operations received by the camera operation unit 208 is transmitted from the camera control CPU 206 to the lens control CPU 112 by communication.

[0031] Next, an example of simultaneous driving of a plurality of optical elements (lenses and diaphragms) within the interchangeable lens 100 will be described. For example, the correction lens 104 is driven in a direction orthogonal to the optical axis, and the zoom lens 125 is driven in the optical axis direction. These two lenses have different roles and may be driven simultaneously. For example, when the user holds the camera system 10 by hand and performs imaging while zooming in a state where camera shake occurs.

[0032] The lens control CPU 112 calculates the required driving amount of the correction lens 104 to correct image blur caused by camera shake detected by a shake sensor (not shown) based on the focal length of the imaging optical system and the angle of camera shake (hereinafter referred to as the camera shake angle). The larger the camera shake angle, the larger the driving amount of the correction lens 104. On the other hand, even when the camera shake angles are the same, the driving amount of the correction lens 104 to obtain a shake correction angle for correcting image blur with respect to the camera shake angle tends to increase as the focal length increases. Therefore, it is necessary to calculate the driving amount of the correction lens 104 according to the camera shake angle and the focal length.

[0033] During zooming, the lens control CPU 112 calculates the driving amount in the optical axis direction of the zoom lens 125 to change the focal length of the imaging optical system according to the amount of change in the angle of view per unit time (zoom speed) instructed by the user operating the lens operation unit 115.

[0034] In this embodiment, in the case where two optical elements are simultaneously driven in this way and the power consumption in driving these two optical elements changes according to the focal length, the upper limit value of the power that can be used for driving each of these two optical elements is controlled.

[0035] Next, with reference to FIGS. 3(a) to 3(d), the power consumption when the correction lens 104 and the zoom lens 125 are driven simultaneously, that is, when power is supplied to both the correction actuator 108 and the zoom actuator 126, will be described. The power used for driving the correction lens 104 and the zoom lens 125 varies according to the focal length of the imaging optics even if the camera shake angle and the amount of change in the angle of view per unit time during zooming are constant. On the other hand, the power supplied from the camera power supply unit 209 to the lens power supply unit 128 has an upper limit. As a result, there is also an upper limit to the power that can be supplied to each actuator in the interchangeable lens 100.

[0036] Conventionally, in order to manage the power supplied to each actuator in the interchangeable lens 100, an upper limit value is set for the power supplied to each actuator (the power that each actuator can use). Specifically, the duty ratio of the PWM control notified from the lens control CPU 112 to each drive circuit is limited to a predetermined value or less. When the duty ratio is limited, the effective voltage when that actuator is driven becomes low, and thereby the power consumption can also be limited.

[0037] When considering the change in the focal length of the interchangeable lens 100, the power consumption when driving the correction lens 104 is maximum at the focal length (70 mm) in FIG. 3(d). Similarly, the power consumption when driving the zoom lens 125 is maximum at the focal length (24 mm) in FIG. 3(a). Generally, a power upper limit value corresponding to the above maximum power consumption is set for each actuator to perform power distribution. This is a method of setting a constant power upper limit value without changing the power distribution according to the focal length.

[0038] However, in this method, problems occur when the total maximum power consumption of the two actuators exceeds the power that can be supplied to the interchangeable lens 100 within the camera system 10. That is, if a constant power upper limit value is always set regardless of the focal length, in order to distribute power to each actuator within the range of power that can be supplied to the interchangeable lens 100, it becomes necessary to limit the driving performance of each actuator. For example, for the correction lens 104, power Ps_max is required to drive it to obtain the maximum shake correction angle at the focal length shown in Fig. 3(d). On the other hand, for the zoom lens 125, power (second power) Pz_max is required to drive it to obtain the maximum change in the angle of view at the focal length shown in Fig. 3(a).

[0039] However, considering the power that can be supplied to the interchangeable lens 100 as the camera system 10, there may be cases where power Ps_max and power Pz_max cannot be supplied simultaneously. In this case, it is necessary to set a power upper limit value less than Pz_max for the driving of the correction lens 104 or to set a power upper limit value less than Pz_max for the driving of the zoom lens 125. As a result, on the premise that a constant power upper limit value is always set, the shake correction angle or the change in the angle of view is restricted. Particularly, in a camera system where an expansion of the shake correction angle or motorization of zooming is required, the above restrictions on the shake correction angle or the change in the angle of view are not preferable.

[0040] Therefore, in this embodiment, according to the focal length of the interchangeable lens 100, the power upper limit value (first upper limit value) for the first power supplied for driving the correction lens 104 and the power upper limit value (second upper limit value) for the second power supplied for driving the zoom lens 125 are changed. Since the power consumption in driving each lens varies for each focal length, if the power upper limit value is also changed accordingly, the limited power can be effectively utilized. For example, at the focal length shown in Fig. 3(a), since the power consumptions of the correction lens 104 and the zoom lens 125 are Ps_max and Pz_max respectively, the respective power upper limit values are set to values equivalent to their power consumptions. Of course, the power consumption varies due to variations such as the weight of the driven lens, the dimensions of each component, and circuit constants. Therefore, it is desirable to set the power upper limit value by adding a margin to the values of Pf_max and Pz_max in consideration of these variations.

[0041] As shown in Fig. 3(b), when the focal length (35 mm) of the interchangeable lens 100 becomes longer than the focal length in Fig. 3(a), the power consumption in driving the correction lens 104 increases, and the power consumption in driving the zoom lens 125 decreases. This is because as the focal length increases, the driving amount of the correction lens 104 required to obtain the same shake correction angle increases, and the driving amount of the zoom lens 125 required to obtain the same change in the angle of view decreases. In this case, a smaller power upper limit value can be set for the zoom lens 125 than when the focal length is as in Fig. 3(a), and a larger power upper limit value can be set for the correction lens 104 accordingly. Thus, the power for driving can be shared between the correction lens 104 and the zoom lens 125 because the power consumptions of the correction lens 104 and the zoom lens 125 have a relationship where when one decreases with the change in the focal length, the other increases. Utilizing this relationship, the reduction in the power consumption in driving one of the correction lens 104 and the zoom lens 125 driven simultaneously can be distributed to the driving of the other.

[0042] In Fig. 3(c), the focal length (50 mm) of the interchangeable lens 100 is even longer than that in Fig. 3(b). At this time, the driving amount of the correction lens 104 required to obtain the same image stabilization angle further increases, and the driving amount of the zoom lens 125 required to obtain the same angle-of-view change amount further decreases. As a result, the power consumption in driving the correction lens 104 further increases, and the power consumption in driving the zoom lens 125 further decreases. For this reason, a power upper limit value smaller than that at the focal length in Fig. 3(b) can be set for the zoom lens 125, and a larger power upper limit value can be set for the correction lens 104.

[0043] As a method for setting the power upper limit value at each focal length in the present embodiment, for example, as shown in Fig. 3(a), the power upper limit value when the focal length of the interchangeable lens 100 is the minimum value (predetermined focal length) within its variable range is used as a reference value. Then, when the focal length changes from the minimum value, the power upper limit value at the changed focal length is set by applying (for example, multiplying) the correction coefficient at the changed focal length to the reference value.

[0044] Also, as described above, since the amount of change in power consumption increases as the amount of change in focal length increases, the power upper limit value may be set so as to increase the difference from the reference value according to the magnitude of the amount of change in focal length from the minimum focal length. For example, the power upper limit value at the current focal length can be calculated by multiplying the reference value of the power upper limit value by the current focal length (mm) / minimum focal length (mm) as a correction coefficient.

[0045] Furthermore, as a method for setting the power upper limit value, it may be set based on the measured value. For example, based on the measured values of the power consumption when driving the correction lens 104 and the zoom lens 125 respectively at each focal length, the power upper limit values for driving these lenses 104 and 125 for each focal length (at different focal lengths) are set. Then, the data regarding the power upper limit value is stored in the internal storage device (storage means) 114 as table data. The data regarding the power upper limit value may be the power upper limit value itself, or data convertible to the power upper limit value. Also, it may be the data of the measured value or the design value of the power consumption used for setting the upper limit value. The lens control CPU 112 reads out the data corresponding to the focal length information detected by the focal length detection unit 119 from the above table data, and sets the power upper limit value according to the focal length information.

[0046] Thus, in this embodiment, by utilizing the relationship that when the power consumption in driving each of the correction lens 104 and the zoom lens 125 increases for one while decreasing for the other in response to the change in the focal length, the power upper limit value for each lens is changed according to the focal length. As a result, the amount of power reduction available for one lens can be distributed to the other lens. Consequently, it becomes unnecessary to limit the driving performance of the two lenses driven simultaneously.

[0047] The above change in the power upper limit value according to the focal length is not limited to the simultaneous driving of the correction lens 104 and the zoom lens 125. That is, it may be performed during the simultaneous driving of any two of the aperture 103, the correction lens 104, the focus lens 105, the floating lens 121, and the zoom lens 125. That is, the first and second optical elements may be any of the aperture 103, the correction lens 104, the focus lens 105, the floating lens 121, and the zoom lens 125. Also, the number of optical elements driven simultaneously may be three or more.

[0048] FIG. 4 shows the process (control method) executed by the lens control CPU 112 according to a program. Here, the case where the correction lens 104 and the zoom lens 125 are driven simultaneously will be described as an example.

[0049] In step S101, the lens control CPU 112 acquires the focal length information of the interchangeable lens 100 from the focal length detection unit 119.

[0050] Next, in step S102, the lens control CPU 112 determines whether to perform the drive of the zoom lens 125 (hereinafter referred to as zoom drive). Specifically, it determines whether a user has performed a zoom operation on the lens operation unit 115 or the camera operation unit 208. When a zoom operation is performed, the lens control CPU 112 can detect the presence or absence of the zoom operation and its content (such as the zoom direction and zoom speed) based on communication from the camera body 200 or a signal from the lens operation unit 115. If a zoom operation has been performed, the lens control CPU 112 proceeds to step S103; if no zoom operation has been performed, it returns to step S101.

[0051] In step S103, the lens control CPU 112 compares the focal lengths before and after the zoom drive based on the content of the zoom operation detected in step S102 and the focal length information acquired in step S101.

[0052] Next, in step S104, the lens control CPU 112 determines whether the focal length after the zoom drive is shorter than the focal length before the zoom drive based on the comparison result in step S103. If the focal length after the zoom drive is shorter than the focal length before the zoom drive, the lens control CPU 112 proceeds to step S105; if the focal length after the zoom drive is longer than the focal length before the zoom drive, it proceeds to step S109.

[0053] In step S105, the lens control CPU 112 increases the power upper limit value in the zoom drive compared to the power upper limit value before the zoom drive. As shown in FIGS. 3(a) to 3(d), this is because as the focal length becomes shorter due to the zoom drive, the driving amount of the zoom lens 125 required to obtain the same amount of change in the angle of view as before the zoom drive increases. Here, the focal length (mm) / minimum focal length (mm) per unit zoom driving amount is used as a correction coefficient and multiplied by the reference value of the power upper limit value of the zoom drive corresponding to the minimum focal length. Thereby, the power upper limit value of the zoom drive for each focal length is set so that a larger power upper limit value is set as the focal length becomes shorter..

[0054] Next, in step S106, the lens control CPU 112 decreases the power upper limit value in the driving of the correction lens 104 (hereinafter referred to as correction driving) compared to the power upper limit value before the zoom drive. As shown in FIGS. 3(a) to 3(d), this is because as the focal length becomes shorter due to the zoom drive, the driving amount of the correction lens 104 required to obtain the same amount of shake correction angle as before the zoom drive decreases. Here, the focal length (mm) / minimum focal length (mm) per unit zoom driving amount is used as a correction coefficient and multiplied by the reference value of the power upper limit value of the correction driving corresponding to the minimum focal length. Thereby, the power upper limit value of the correction driving for each focal length is set so that a smaller power upper limit value is set as the focal length becomes shorter. Then, the lens control CPU 112 proceeds to step S107.

[0055] On the other hand, in step S109, the lens control CPU 112 decreases the power upper limit value in the zoom drive compared to the power upper limit value before the zoom drive. As shown in FIGS. 3(a) to 3(d), this is because as the focal length becomes longer due to the zoom drive, the driving amount of the zoom lens 125 required to obtain the same amount of change in the angle of view as before the zoom drive decreases. Here, by the same setting method as in step S105, the power upper limit value of the zoom drive for each focal length is set so that a smaller power upper limit value is set as the focal length becomes longer.

[0056] Next, in step S110, the lens control CPU 112 increases the power upper limit value in the correction drive to be higher than the power upper limit value before the zoom drive. As shown in FIGS. 3(a) to 3(d), this is because as the focal length increases due to the zoom drive, the driving amount of the correction lens 104 required to obtain the same image stabilization angle as before the zoom drive increases. Here, in the same setting method as in step S106, the power upper limit value of the correction drive for each focal length is set so that a larger power upper limit value is set as the focal length increases. Then, the lens control CPU 112 proceeds to step S107.

[0057] In step S107, the lens control CPU 112 controls the zoom drive circuit 127 to drive the zoom lens 125. At this time, the lens control CPU 112 causes the lens power supply unit 128 to supply power to the zoom drive circuit 127 that is equal to or less than the power upper limit value of the zoom drive set in step S105 or step S109.

[0058] Next, in step S108, the lens control CPU 112 controls the correction drive circuit 109 to drive the correction lens 104. At this time, the lens control CPU 112 causes the lens power supply unit 128 to supply power to the correction drive circuit 109 that is equal to or less than the power upper limit value of the correction drive set in step S106 or step S110.

[0059] Through the above processing, when the zoom drive and the correction drive are performed simultaneously, power can be mutually borrowed for both drives, so that limitations on the driving performance of the zoom drive and the correction drive can be avoided.

[0060] In addition, in this embodiment, the case where the power upper limit value for driving each optical element is changed for each focal length has been described. However, the entire variable range of the focal length may be divided into a plurality of ranges, and the power upper limit value for driving each optical element may be changed for each range.

[0061] In addition, in this embodiment, although the case where the lens device receives power supply from the imaging device connected thereto has been described, when the lens device receives power supply from an external power source connected thereto, the same processing as the processing shown in FIG. 4 may be performed.

[0062] The above embodiments include the following configurations.

[0063] (Configuration 1) A lens device having a first optical element and a second optical element, and having a variable focal length, a first driving means for driving the first optical element, a second driving means for driving the second optical element, a power supply means for supplying power to the first and second driving means, and a control means for controlling the supply of the power, wherein the control means acquires information regarding the focal length, and when supplying power to both the first driving means and the second driving means, changes a first upper limit value for the power supplied to the first driving means and a second upper limit value for the power supplied to the second driving means according to the information regarding the focal length. The lens device is characterized by this. (Configuration 2) The control means increases one of the first and second upper limit values and decreases the other according to the information regarding the focal length. The lens device according to Configuration 1 is characterized by this. (Configuration 3) The control means changes the first and second upper limit values according to the information regarding the focal length such that one of the first and second upper limit values becomes larger and the other becomes smaller as the focal length becomes longer or shorter. The lens device according to Configuration 1 or 2 is characterized by this. (Configuration 4) The control means uses the first and second upper limit values at a predetermined focal length as reference values, and applies a coefficient corresponding to the information regarding the focal length to the reference values, thereby changing the first and second upper limit values according to the information regarding the focal length. The lens device according to any one of Configurations 1 to 3, characterized in that. (Configuration 5) It has storage means for storing data regarding the first and second upper limit values at different focal lengths, The control means uses the data to change the first and second upper limit values according to the information regarding the focal length. The lens device according to any one of Configurations 1 to 3, characterized in that. (Configuration 6) The first optical element is a correction lens that moves with respect to the optical axis to correct image shake, The second optical element is a zoom lens that performs zooming by moving along the optical axis. The lens device according to any one of Configurations 1 to 5, characterized in that. (Configuration 7) The power supply means supplies power to the first and second drive means using the power supplied from an imaging device or an external power source connected to the lens device. The lens device according to any one of Configurations 1 to 6, characterized in that. (Configuration 8) An imaging device, characterized in that the lens device according to any one of Configurations 1 to 7 is detachably mounted and power is supplied to the power supply means.

[0064] (Other Embodiments) 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 (for example, ASIC) that realizes one or more functions.

[0065] Each of the embodiments described above is merely a representative example, and various modifications and changes can be made to each embodiment when implementing the present invention.

Description of Signs

[0066] 100 Exchange lens 104 Correction lens 125 Zoom lens 112 Lens control CPU 128 Lens power supply unit 119 Focal length detection unit

Claims

1. A lens device having a first optical element and a second optical element, and having a variable focal length, comprising: first driving means for driving the first optical element; second driving means for driving the second optical element; power supply means for supplying power to the first and second driving means; control means for controlling the supply of the power, wherein the control means acquires information regarding the focal length, and when supplying power to both the first driving means and the second driving means, changes a first upper limit value for the power supplied to the first driving means and a second upper limit value for the power supplied to the second driving means according to the information regarding the focal length.

2. The lens device according to claim 1, wherein the control means increases one of the first and second upper limit values and decreases the other according to the information regarding the focal length.

3. The lens device according to claim 1, wherein the control means changes the first and second upper limit values according to the information regarding the focal length such that one of the first and second upper limit values increases and the other decreases as the focal length becomes longer or shorter.

4. The lens device according to claim 1, wherein the control means uses, as a reference value, the first and second upper limit values at a predetermined focal length, and applies a coefficient according to the information regarding the focal length to the reference value, thereby changing the first and second upper limit values according to the information regarding the focal length.

5. storage means for storing data regarding the first and second upper limit values at different focal lengths, wherein the control means changes the first and second upper limit values according to the information regarding the focal length using the data.

6. The first optical element is a correction lens that moves with respect to the optical axis to correct image shake, and the second optical element is a zoom lens that performs zooming by moving along the optical axis.

7. The lens device according to claim 1, wherein the power supply means supplies power to the first and second driving means using power supplied from an imaging device or an external power source connected to the lens device.

8. An imaging device, wherein the lens device according to any one of claims 1 to 7 is detachably mounted, and power is supplied to the power supply means.

9. A control method for a lens device having a first optical element and a second optical element and having a variable focal length, comprising: acquiring information regarding the focal length; when supplying power to both a first driving means for driving the first optical element and a second driving means for driving the second optical element, changing a first upper limit value for the power supplied to the first driving means and a second upper limit value for the power supplied to the second driving means according to the information regarding the focal length.

10. A program, wherein a process according to the control method of claim 9 is executed by a computer of the lens device.

Images