Lens device, imaging system, imaging device, and control method for lens device

Abstract

This lens device reduces noise caused by lens drive that is recorded during video recording, even when different cameras are attached. [Solution] A lens device that is detachably attached to an imaging device and has a lens communication unit that communicates with the imaging device comprises a lens drive control unit that drives optical elements included in the lens device and a storage unit that stores information regarding the driving sound of the optical elements. The lens drive control unit determines the driving conditions of the optical elements based on the sound transmission characteristics of the imaging device and information regarding the driving sound when driving the optical elements.

Description

Technical Field

[0001] The present invention relates to a lens device, an imaging system including the lens device, an imaging device, and a method for controlling the lens device.

Background Art

[0002] Some interchangeable-lens cameras and compact cameras have a video shooting function. When shooting a video with these cameras, sound recording is simultaneously performed using a microphone inside the camera or a microphone installed outside the camera. When shooting a video including such sound recording, in order to prevent the driving sound of the actuator that drives the focusing lens from being recorded, the movement method is changed from that during still image shooting to achieve silence. In Patent Document 1, silence is achieved by setting a limit speed during movement based on the sound generated in the lens device when moving the focusing lens. Further, Patent Document 2 proposes changing the moving speed of the lens according to the ambient environmental sound. In this technique, when the ambient environmental sound is small, the driving speed of the lens is reduced to reduce the driving sound recorded in the video. When the ambient environmental sound is large, since the driving sound of the lens is masked by the surrounding sound, the lens can be moved faster.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In lens devices used in interchangeable-lens cameras, the lens device may not be attached to just one camera. Depending on the camera to which it is attached, the rigidity of the camera body may differ, and the position of the internal microphone may also differ. In such cases, even if the lens drive speed is changed according to the speed limit specified in the lens device, as in the technology disclosed in Patent Documents 1 or 2, the expected reduction in sound recorded by the microphone may not be achieved. As a result, unwanted noise caused by the lens drive may be recorded in the microphone of the imaging device such as a camera.

[0005] In view of these circumstances, one of the objectives of the present invention is to provide a lens device, imaging system, imaging device, and a control method for the lens device that reduce noise caused by lens drive recorded during video recording, even when different cameras are attached. [Means for solving the problem]

[0006] To achieve the above objective, a lens device according to one aspect of the present invention is: A lens device that is detachably attached to an imaging device and includes a lens communication unit that communicates with the imaging device, A lens drive control unit that drives the optical elements included in the lens device, The system includes a storage unit that stores information relating to the driving sound of the optical element, The lens drive control unit is characterized by determining the driving conditions for the optical element based on the sound transmission characteristics of the imaging device and information regarding the driving sound when driving the optical element. [Effects of the Invention]

[0007] According to the present invention, even when different cameras are attached, noise caused by lens drive that is recorded during video recording can be reduced. [Brief explanation of the drawing]

[0008] [Figure 1]This is a block diagram of the camera system related to Example 1. [Figure 2] This is a block diagram showing the functional configuration of the camera microcontroller and lens microcontroller. [Figure 3] This is a flowchart illustrating the noise reduction process performed in the lens drive control unit. [Figure 4] This figure shows an example of the vibration transmission characteristics of a camera. [Figure 5] This diagram shows the relationship between the motor speed of the focusing lens and the disturbance frequency. [Figure 6] This diagram shows the relationship between the rotation speed of the MF ring and the motor speed. [Figure 7] This is a flowchart illustrating the noise reduction process performed in the camera drive control unit. [Figure 8] This is an illustrative diagram showing how the focus lens moves during AF search operation. [Figure 9] This is a control block diagram of the focus lens in Example 2. [Figure 10] This figure shows the frequency response characteristics of a feedback control system. [Figure 11] This figure shows the frequency response characteristics of a feedback control system (when countermeasures are implemented). [Figure 12] This is a block diagram of the components of the camera microcontroller and lens microcontroller in Example 3. [Figure 13] This figure shows the frequency analysis results from the audio analysis unit. [Modes for carrying out the invention]

[0009] Hereinafter, preferred embodiments for implementing the present invention will be described in detail as examples based on the accompanying drawings. However, the dimensions, materials, shapes, relative positions of components, etc. described in the following examples are arbitrary and can be changed according to the configuration of the device to which the present disclosure is applied or various conditions. Also, in the drawings, the same reference numerals are used between the drawings to indicate elements that are identical or functionally similar. And, for the purpose of facilitating the understanding of the present invention, configurations with a low direct relevance in the present invention may be omitted in the drawings and related descriptions, for example.

[0010] <Example 1> FIG. 1 is a block diagram of a camera system which is an example of an imaging system according to Example 1 of the present invention. The illustrated camera system 1 includes an imaging device 200 (camera body) and a lens device 100 (interchangeable lens) detachably attached to the imaging device 200. The imaging device 200 and the lens device 100 are mechanically coupled by a mount 230 and electrically communicatively connected via contacts indicated by circles in FIG. 1. Note that the communication method is not limited to electrical communication, and other means such as optical communication may be used. Also, power is supplied from the imaging device 200 to the lens device 100 via the contacts.

[0011] Next, details of the lens device 100 according to Example 1 will be described. The lens device 100 includes a photographing optical system constituted by a plurality of optical lens units and a lens electric circuit unit 110. The photographing optical system is configured to form an optical image of an object (subject). In the example shown in FIG. 1, it includes a focus lens 101, a zoom lens 102, and an aperture 103.

[0012] The lens electrical circuit section 110 includes a lens microcontroller 111, a communication means 112, a memory 113, a drive circuit 114, a drive circuit 116, a position detection circuit 115, a position detection circuit 117, and an open detection switch 118. In this embodiment, the lens electrical circuit section 110 also includes a gyroscope 119 and a lens operating section 120. The gyroscope 119 is a sensor that detects angular velocity and is installed when the lens device 100 has an anti-vibration mechanism, as in this embodiment. The lens operating section 120 is an operating section such as an MF (Manual Focus) ring and also includes a sensor that detects the rotation of the ring.

[0013] Communication means 112 communicates between the lens microcontroller 111 and the camera microcontroller 212 provided in the imaging device 200 via communication means 216 on the imaging device 200 side. Memory 113 is provided as a recording area composed of ROM and RAM, etc., and stores protocols and data used for communication with the imaging device 200. Drive circuit 114 controls the actuator (ACT) that drives the focus lens 101 in the direction of the optical axis. Position detection circuit 115 detects the position of the focus lens 101 in the direction of the optical axis. Drive circuit 116 controls the actuator (ACT) that drives the opening and closing of the aperture 103. Position detection circuit 117 detects the position of the zoom lens 102 in the direction of the optical axis. Open aperture detection switch 118 detects whether the aperture 103 is in the open state or not.

[0014] The lens microcontroller 111 is connected to the communication means 112, memory 113, drive circuit 114, drive circuit 116, position detection circuit 115, position detection circuit 117, open detection switch 118, gyroscope 119, and lens operation unit 120, and controls the lens device 100. Specifically, the lens microcontroller 111 drives the focus lens 101 by controlling the ACT via the drive circuit 114 based on the position information of the focus lens 101 detected by the position detection circuit 115. The lens microcontroller 111 adjusts the focus of the lens device 100 by moving the actuator (ACT), such as a stepping motor, via the drive circuit 114 to move the focus lens 101 in the direction of the optical axis.

[0015] Furthermore, the lens microcontroller 111 controls the ACT via the drive circuit 116 to drive the aperture 103 according to commands from the imaging device 200 obtained via the communication means 112. The aperture 103 can adjust the amount of light incident on the image sensor 211 of the imaging device 200, which will be described later, by this opening and closing drive. For example, stepping motors can be used for both ACTs mentioned here. The lens microcontroller 111 also detects the amount of rotation of the MF ring, which is the lens operating part 120, and gives a command to the drive circuit 114 to drive the focus lens 101 according to the detected amount of rotation.

[0016] The position detection circuits 115 and 117 have the function of converting the signals from a sensor, such as an encoder, into signals that the lens microcontroller 111 can receive. In the lens device 100, which requires high focusing accuracy determined by the allowable circle of confusion δ of the focus determined by the image sensor 211, a sensor with particularly high resolution is used as the position detection circuit 115.

[0017] The imaging device 200 according to this embodiment 1 includes a camera electrical circuit unit 210, a main mirror 201, a sub-mirror 202, a viewfinder optical system 203, and a viewfinder 204. In this embodiment, a single-lens reflex digital camera is used as an example of the imaging device 200, but the present invention may also be applied to other imaging devices such as digital video cameras and mirrorless cameras.

[0018] In the illustrated imaging device 200, the main mirror 201 and sub-mirror 202 are configured to move between a mirror-down state, where these mirrors are inserted into the optical path as shown in Figure 1, and a mirror-up state (not shown), where they are retracted from the optical path. The main mirror 201 is composed of, for example, a half-mirror. In the mirror-down state, it reflects a portion of the incident light to the finder optical system 203, making the object observable in the finder 204, while transmitting the remaining incident light. The incident light that has passed through the main mirror 201 is reflected by the sub-mirror 202. On the other hand, in the mirror-up state, the incident light reaches the image sensor 211.

[0019] The camera electrical circuit unit 210 includes an image sensor 211, a camera microcontroller 212, a photometer 213, a shutter 214, a display means 215, a communication means 216, and a camera memory 217. The camera electrical circuit unit 210 also includes a power supply 218, a camera operation unit 219, a focus detection unit 220, and a built-in microphone 221.

[0020] The image sensor 211 is a photoelectric conversion element that converts the optical image formed by the imaging optical system of the lens device 100 into photoelectric form, and is composed of a CMOS sensor or a CCD sensor. The photometering unit 213 measures the amount of light of the optical image incident on the image sensor 211. The shutter 214 controls the exposure time of the image sensor 211 by opening and closing. The display means 215 displays various camera information. The camera microcontroller 212 acquires information of the lens device 100 (e.g., identification information, aperture value, etc.) by communicating with the lens microcontroller 111 via the communication means 216, which will be described later. In communication, the camera microcontroller 212 can also issue initialization commands to the lens microcontroller 111 and instruct the driving of the focus lens 101 and other optical elements of the imaging optical system.

[0021] The communication means 216 enables communication between the camera microcontroller 212 and the lens microcontroller 111 of the lens device 100 via contacts between them. A general 3-wire clock-synchronous communication protocol can be used for this communication. The camera memory 217 consists of ROM, RAM, etc., and stores information used by the camera microcontroller 212, the program on which the camera microcontroller 212 operates, and information acquired by the camera microcontroller 212 from the lens device 100. The camera operation unit 219 consists of various operation switches mounted on the imaging device 200. Specific examples of the camera operation unit 219 include a shutter release button and switches for setting the shooting mode and shooting conditions of the imaging device 200. Signals from the various switches are transmitted to the camera microcontroller 212, and the operation of each component in the imaging device 200 is executed accordingly.

[0022] The camera microcontroller 212 also functions as an automatic focus adjustment means 2121 (see Figure 2) that determines whether the amount of defocus detected by the focus detection unit 220 is within the focus detection range. If the amount of defocus is not within the focus range, the camera microcontroller 212 drives the focus lens 101 to the lens device 100 via the communication means 216 to perform automatic focus adjustment. If the amount of defocus is within the focus range, the automatic focus adjustment is terminated. The method for reducing the sound generated when the focus lens 101 is driven in this embodiment will be described later. The built-in microphone 221 is an audio input means for recording sound during video recording. In this embodiment, the built-in microphone 221 is located in the camera electrical circuit unit 210 as the microphone for audio input, but the microphone may be provided so as to be connected from outside the imaging device 200.

[0023] Next, the functions of the camera microcontroller 212 and the lens microcontroller 111 in this embodiment will be described in detail using Figure 2. Figure 2 is a block diagram showing the functional configuration of the camera microcontroller 212 and the lens microcontroller 111. In Figure 2, only the configurations directly related to the present invention, such as the configuration related to driving the focus lens 101 in the lens device 100, will be shown. Configurations related to the zoom lens 102 and aperture 103, which are less relevant to the present invention in this embodiment, will be omitted. Although the description in this embodiment focuses on the driving of the focus lens 101, the present invention is applicable to each or more optical elements that can be driven in a lens device, such as other lenses.

[0024] The lens microcontroller 111 includes a lens drive control unit 1110 and a focus control unit 1111. The focus control unit 1111 controls the drive circuit 114 to drive the focus lens 101 according to the drive conditions of the lens drive control unit 1110. Details of the operation of the lens drive control unit 1110 will be described later. The camera microcontroller 212 includes a camera drive control unit 2120 and an autofocus adjustment means 2121.

[0025] In the prior art disclosed in Patent Documents 1 or 2, attempts are made to reduce the sound that can be recorded in the microphone due to the motor drive of the lens device by reducing the speed of the motor drive of the lens device. However, the inventors of the present invention have recognized that when the lens device is attached to the imaging device, sound can also be generated in the imaging device due to the motor drive of the lens device. For example, if the rigidity of the camera body is low, vibrations generated when the lens is driven by the stepping motor can excite resonance in the camera body, and unwanted noise generated by this can be recorded in the microphone. When different cameras are used to attach the lens device, the conditions for resonance differ depending on the camera body to which it is attached, requiring individual adjustments for each imaging device. In the present invention, further reduction of sound recorded in the microphone is achieved by taking into account the resonance of the camera body in each imaging device.

[0026] The details of the present invention will be explained below, starting with an example of a method for controlling the focus lens 101 when the lens operation unit 120 is operated, with reference to the flowchart shown in Figure 3. When the lens device 100 is attached to the imaging device 200 via the lens mount 230, the lens drive control unit 1110 starts the control process and executes the process in step S301.

[0027] In step S301, the lens drive control unit 1110 obtains information on the camera's vibration transmission characteristics from the camera drive control unit 2120, as shown in Figure 4. This characteristic represents how easily vibrations are transmitted from the camera's (imaging device 200) mount 230 to the built-in microphone 221 in the camera's electrical circuit unit 210. Since the vibration transmission characteristics are determined by the material and structure of the imaging device 200's body, characteristic data is obtained through structural analysis using design values ​​or by using the actual device, and stored in the camera memory 217. The lens drive control unit 1110 obtains the vibration transmission characteristics stored in the camera memory 217. Once the vibration transmission characteristics are obtained, the lens drive control unit 1110 moves the flow to step S302.

[0028] In step S302, the lens drive control unit 1110 sets a prohibited speed range, which will be described later, as a speed control parameter. Here, in the vibration transmission characteristics illustrated in Figure 4, it is shown that there are two peaks, resonance A and resonance B, as the frequency increases. However, the number of resonances showing peaks is illustrative and may be one or more. Note that the vibration transmission characteristics to be acquired are not limited to a graph as shown in the figure, but may also be acquired as an equation such as a transfer function, or only the information of the resonance frequency may be acquired.

[0029] In the lens device 100, when the focus lens 101 is driven, vibrations corresponding to its speed are generated. Figure 5 is a graph showing the relationship between the lens drive speed when the focus lens 101 is driven and the frequency of the periodic disturbance, which is the vibration generated. When a stepping motor, as exemplified, is used as the actuator for the focus lens 101, it is known that cogging torque is generated according to the number of poles of the stepping motor. Since this cogging torque is a disturbance that acts periodically depending on the rotation angle, its frequency changes depending on the rotation speed of the motor, as shown in Figure 5.

[0030] Figure 5 shows the drive conditions for the focus lens during MF operation, calculated by the lens drive control unit 1110. When the lens operating unit 120 is an MF ring, the speed of the focus lens, i.e., the motor speed, is set according to the rotation speed of the ring. As can be seen from Figure 5, the motor speed V A When the focus lens 101 is driven, the frequency of vibrations due to disturbances changes, and disturbances that reach the frequency of resonance A can be generated. That is, motor speed V A When the focus lens 101 is driven, the periodic disturbance excites resonance A in the camera body, and as a result, the drive noise that can be recorded by the built-in microphone 221 becomes more resonant.

[0031] Therefore, in this embodiment, as shown in Figure 6, the motor speed is V A The driving conditions are set to prevent this from happening. For example, depending on the magnitude of the resonance, such as a large resonance peak or a wide range of tails relative to the resonance peak, the prohibited speed band Δ may occur as shown in Figure 5. f Determine the motor speed as well. A In contrast, width Δ V By avoiding the use of [this method], the excitation of resonance can be further suppressed.

[0032] Next, an example of how the camera drive control unit 2120 controls the drive of the lens device 100 will be explained with reference to the flowchart shown in Figure 7. The autofocus adjustment means 2121 determines how to move the focus lens 101 according to the amount of defocus detected by the focus detection unit 220. For example, if the focus is significantly off with respect to the subject and the focus position is unknown, the focus lens 101 is moved at a constant speed to search for the subject (search drive).

[0033] The autofocus adjustment means 2121 sets the drive speed of the focus lens 101 based on the focus detection unit 220 and the image plane formed on the image sensor 211. At that time, the autofocus adjustment means 2121 sets the drive speed by receiving optical information from the lens device 100. When the lens device 100 is attached to the imaging device 200 via the lens mount 230, the camera drive control unit 2120 starts control processing and executes the process of step S701.

[0034] In step S701, the camera drive control unit 2120 receives information from the lens drive control unit 1110 regarding the relationship between motor speed and disturbance frequency, as shown in Figure 5, specifically the relationship between the lens drive characteristics and the frequency of generated noise. Subsequently, the camera drive control unit 2120 proceeds to step S702.

[0035] The motor speed can be converted into the speed at which the image plane changes when focusing is achieved by multiplying it by the focus sensitivity. Therefore, the speed at which the image plane changes that should be avoided (the prohibited speed range) can be determined as a speed control parameter from the relationship shown in Figure 5. In step S702, the camera drive control unit 2120 determines the prohibited speed range based on the relationship information between the motor speed and the disturbance frequency acquired in step S701. The determined prohibited speed range is notified to the autofocus adjustment means 2121, and the process proceeds to step S703.

[0036] In step S703, the autofocus adjustment means 2121 searches for the focus lens at a drive speed that does not cause a resonant disturbance A by referring to the prohibited speed band. This reduces the noise caused by the motor drive of the lens device 100 during video recording in the camera system 1, and reduces the level of noise recorded by the built-in microphone 221. Since the focus sensitivity also differs depending on the position of the focus lens 101, the prohibited speed band may be widened by the range of focus sensitivity by receiving minimum and maximum value information of the focus sensitivity from the lens device 100.

[0037] Depending on the shooting scene, the focus detection unit 220 may detect a moving subject and move the focus lens 101 to follow the subject's movement. Figure 8 shows the position of the focus lens 101 when it follows the subject's movement. The dotted line represents the trajectory of the focus lens 101 that should move in accordance with the subject's movement. If the speed at this time falls within the prohibited speed range determined by the camera drive control unit 2120, driving in accordance with the movement of the dotted line will result in a periodic disturbance such as resonance A. In such cases, as shown by the solid line in Figure 8, by moving in small increments at a speed faster than the prohibited speed range, it is possible to drive in accordance with the subject while avoiding resonance A.

[0038] As described above, the lens device 100 according to the present invention is detachably mounted on the imaging device 200 and includes a communication means 112 that functions as a lens communication unit for communicating with the imaging device 200. The lens device 100 further includes a lens drive control unit 1110 and a memory 113 that functions as an example of a storage unit. The lens drive control unit 1110 drives a focus lens 101, which is shown as an example of an optical element included in the lens device 100. Note that the focus lens 101 is an example of an optical element, and the optical element may be any other optical element that is required to be driven in the optical axis direction and may be included in the lens device as needed. The memory 113 stores information regarding the drive sound of the focus lens 101 (optical element), for example, as illustrated in the relationship between motor speed and disturbance frequency shown in Figure 5. The lens drive control unit 1110 then determines the driving conditions of the focus lens 101 based on information regarding the sound transmission characteristics, which is illustrated in Figure 4 as the vibration transmission characteristics of the imaging device 200, and the drive sound information stored in the memory 113. In this embodiment, as an example of these driving conditions, Δ is set as the prohibited zone for the driving speed of ACT. V This is determined. By arranging the lens device 100 in this way, even if the lens device 100 is attached to a different camera as the imaging device 200, the noise caused by lens drive that is recorded in the imaging device 200 during video recording can be reduced.

[0039] Furthermore, the lens device 100 described above may further include a lens operating unit 120 that functions as an example of an operating member for driving the focus lens 101. In this case, the lens drive control unit 1110 can determine the driving conditions for the focus lens 101 based on the information regarding the driving sound and the information regarding the sound transmission characteristics described above, as well as the amount of operation of the lens operating unit 120. In this embodiment, the lens device 100 is attached to the imaging device 200 via a lens mount 230. In this case, the vibration transmission characteristics are preferably the vibration transmission rate from the lens mount 230 to the built-in microphone 221 provided in the imaging device 200. In this embodiment, when the lens device 100 is attached to the imaging device 200, the lens drive control unit 1110 acquires the vibration transmission characteristics stored in the camera memory 217 of the imaging device 200 via the communication means 112. However, the vibration transmission characteristics may also be stored in the memory 113 of the lens device 100 in advance and read out and acquired when it is determined what kind of imaging device 200 is attached to.

[0040] Furthermore, the present invention can also constitute an imaging device 200. Specifically, the imaging device 200 includes a communication means 216 that functions as an example of a camera communication unit that communicates with the mounted lens device 100. The imaging device 200 also includes a camera drive control unit 2120 and a memory 217 that functions as an example of a storage unit. The camera drive control unit 2120 drives the focus lens 101, which is shown as an example of an optical element included in the lens device 100, via the communication means 216. The memory 217 stores the information regarding the sound transmission characteristics in the imaging device 200 described above. The camera drive control unit 2120 then determines the driving conditions for the focus lens 101 based on the information regarding the drive sound of the lens device 100, the optical information of the lens device 100, and the transmission characteristics stored in the memory 217.

[0041] Furthermore, the present invention can also constitute a camera system 1, as shown as an example of an imaging system comprising the lens device 100 and imaging device 200 described above. Moreover, the present invention can also constitute a control method for the lens device 100, including, for example, the steps illustrated in Figure 3 or Figure 7.

[0042] <Example 2> In Example 1, a method for reducing noise was described when the actuator that moves the focus lens 101 is, for example, a stepping motor. In contrast, this example describes how to move the focus lens 101 when the actuator that moves it is an ultrasonic motor or a VCM (Voice Coil Motor), or when it is an IS (Image Stabilizer) lens. Note that, apart from the difference in actuator, the other configurations are the same or similar as those described in Example 1, so the explanation is omitted here, and only the differences are described below.

[0043] Figure 9 shows an example block diagram of a control system when operating the focus lens 101 with an actuator such as an ultrasonic motor or VCM. In the case of such actuators, the stable position is not determined by the relationship between the energized phase of the coil and the position of the magnetic pole, as in a stepping motor, so the position is controlled by a feedback control system as shown in Figure 9. Specifically, the position detection circuit 115 is used to calculate the difference between the position of the focus lens 101 and the target position, and the feedback controller 911 calculates an operation variable to correct the position. Then, based on the calculated operation variable, control is performed to bring the focus lens 101 closer to the target position.

[0044] Figure 10 shows the gain characteristics of the frequency response of the feedback control system. The dotted line represents the open-loop characteristic, and the solid line represents the closed-loop characteristic. The frequency at which the gain of the open-loop characteristic crosses 0 [dB] is called the zero-crossing frequency. Depending on the adjustment of the parameters of the feedback controller 911, the gain near the zero-crossing frequency may exceed 0 [dB] as shown by the solid line, making the control system prone to oscillation at that frequency.

[0045] When information on the camera's vibration transmission characteristics, as shown in Figure 4, is received, if the zero-crossing frequency and resonances A and B are close in frequency, vibrations caused by the control of the focus lens 101 will excite the camera body's resonance. Therefore, in the lens device of this embodiment, the zero-crossing frequency information is stored in the memory 113 and referred to by the lens drive control unit 1110 when determining how to move the focus lens 101.

[0046] Specifically, it is conceivable that noise reduction parameters be prepared as parameters for the feedback controller 911 in Figure 9, and that when the zero-crossing frequency and resonance A are close, the focus lens 101 can be controlled using these noise reduction parameters. The noise reduction parameters are parameters that are adjusted so that the gain near the zero-crossing frequency does not significantly exceed 0 dB in the frequency response shown in Figure 10.

[0047] If the lens being driven is an IS (image stabilization) lens, and the imaging device 200 is a model equipped with IIS (imager IS function), the following can also be considered: When the IS lens and imager IS are controlled in coordination, the amount of drive required for the IS lens can be reduced by decreasing the correction ratio on the IS lens side. Reducing the amount of drive required for the IS lens also reduces the component of the lens that vibrates at the zero-crossing frequency, thus reducing the disturbance transmitted to the imaging device 200.

[0048] Next, we will explain the processing of frequencies different from the zero-crossing frequency. Here, as shown in Figure 4, when the camera body has a frequency response with resonances A and B, we assume that resonance A is at a frequency close to the zero-crossing frequency, and resonance B is at a higher frequency. The solid line in Figure 11 represents the closed-loop characteristics of the feedback controller of the focus lens 101, similar to Figure 10. When the frequency response is measured for the lens device alone, there is no resonance at the frequency of resonance B, but when it is attached to the imaging device 200, resonance B may appear in the frequency response. For such resonances, the excitation of the resonance can be prevented by applying a band-reject filter as shown by the dotted line in Figure 11.

[0049] More specifically, the lens drive control unit 1110 notifies the feedback controller 911 of the focus control unit 1111 to add a band-reject filter as a digital filter. By adjusting the parameters of the feedback controller in this way to avoid exciting resonance in the camera body, the noise recorded in the video can be reduced.

[0050] <Example 3> Next, regarding Embodiment 3 of the present invention, a block diagram showing the functional configuration of the camera microcontroller and the lens microcontroller will be described with reference to Figure 12, in the same format as Figure 2. In the following description, configurations that are the same as or similar to the configuration described in Embodiment 1 will be given the same reference numerals in the drawings and will not be described here, and only the different configurations will be described.

[0051] As shown in Figure 12, the imaging device 200-1 according to this embodiment has an external microphone 300 and an audio analysis unit 2122 added to the configuration described in Embodiments 1 and 2. If the vibration transmission characteristics including the external microphone 300 are stored in the camera memory 217 of the imaging device 200-1, the various actuators of the lens device 100 can be operated in the same way as in Embodiments 1 or 2 to avoid exciting resonance. However, since there are various types of external microphones 300, there may be cases where the vibration transmission characteristics from the lens mount 230 to the external microphone when the external microphone 300 is attached are unknown. This embodiment describes a method for reducing lens drive noise recorded in video in such cases, and the details are explained below.

[0052] In this embodiment, the camera microcontroller 212-1 has a sound analysis unit 2122 in addition to the camera drive control unit 2120. In the illustrated camera system, when the vibration transmission characteristics up to the external microphone 300 are unknown, the lens drive control unit 1110 and the camera drive control unit 2120 first drive the focus lens 101 without any processing to avoid the resonant frequency. The sound analysis unit 2122 has the function of acquiring and analyzing the audio signals from the built-in microphone 221 inside the imaging device 200-1 and the external microphone 300. The sound analysis unit 2122 estimates the vibration transmission characteristics of the imaging device 200-1, including the external microphone 300, by analyzing the audio recorded when the various actuators of the lens device 100 are operated. The actuators themselves may be driven during normal operation, such as for focusing if it is a focus lens, or they may be driven as a calibration function of the imaging device 200.

[0053] The audio analysis unit 2122 extracts audio signals from the built-in microphone 221 and the external microphone 300 for the same period and performs frequency analysis by performing FFT processing. Figure 13 shows an example of the results of frequency analysis of the audio signals from the built-in microphone 221 and the external microphone 300. The solid line represents the results of the analysis of the audio signal from the built-in microphone 221, and the dotted line represents the results of the analysis of the audio signal from the external microphone 300.

[0054] According to Figure 13, it is conceivable that the vibrations of resonances A and B of the camera body are attenuated in the signal from the external microphone 300. Resonance C is observed in the waveform of the external microphone 300, which is thought to be due to the rigidity of the external microphone 300 itself and the rigidity of the mounting part of the external microphone 300 appearing as resonance. If these rigidities are sufficiently high, the frequency will be higher than that of resonances A and B, and it is possible that the signal recorded in the video will be difficult to hear. If there is a resonance C that is only visible in the external microphone 300, and if it is at a frequency that is easily audible within the range of human hearing, then, as in Example 1 or 2, it is necessary to determine the actuator driving conditions that take resonance C into consideration.

[0055] In this embodiment, the audio analysis unit 2122 estimates the vibration transmission characteristics of the external microphone 300, and the control processing performed in Embodiment 1 or 2 is executed by referring to the estimated vibration transmission characteristics. By obtaining the vibration transmission characteristics in this way, the lens drive noise recorded in the video when the external microphone 300 is attached can be reduced.

[0056] As described above, the lens device 100 according to the present invention can also be used by attaching it to an imaging device 200-1 having an external microphone 300. In this case, the external microphone 300 may be attachable to the imaging device 200-1. When the external microphone 300 is attached or used, even if the above-described embodiment 1 or 2 is applied, there is a concern that the possibility of unwanted noise due to resonance of the external microphone 300 being recorded cannot be completely reduced. In such cases, the camera drive control unit 2120 may determine the driving conditions of the focus lens 101 without using vibration transmission characteristics. Furthermore, if the imaging device 200-1 is equipped with a sound analysis unit 2122 that analyzes the sound recorded by the external microphone 300, the sound analysis unit 2122 may also function as an estimation means in the present invention. In this case, the audio analysis unit 2122 analyzes the recorded sound to estimate the vibration transmission characteristics of the imaging device 200-1, including the external microphone 300, and the camera drive control unit 2120 can use these vibration transmission characteristics to determine the driving conditions for the focus lens 101.

[0057] By arranging such a configuration, even after attaching the external microphone 300, noise caused by lens drive recorded in the imaging device 200-1 during video recording can be reduced. Furthermore, even if the vibration transmission characteristics of the imaging device 200 as exemplified in Example 1 or 2 are not stored in the memory 217, the objective of the present invention can also be achieved by arranging the sound analysis unit 2122 and analyzing the sound recorded by the built-in microphone 221.

[0058] Preferred embodiments of the present invention have been described above. However, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of its essence. Furthermore, the contents described in each embodiment can be combined as appropriate.

[0059] Furthermore, the present invention includes the following configuration and method. (Composition 1) A lens device that is detachably attached to an imaging device and includes a lens communication unit that communicates with the imaging device, A lens drive control unit that drives the optical elements included in the lens device, The system includes a storage unit that stores information relating to the driving sound of the optical element, The lens device is characterized in that the lens drive control unit determines the driving conditions for the optical element based on the sound transmission characteristics of the imaging device and information regarding the driving sound when driving the optical element. (Configuration 2) It further includes an operating member for driving an optical element, The lens device according to configuration 1, characterized in that the lens drive control unit determines the driving conditions of the optical element based on the amount of operation of the operating member, the transmission characteristics, and the stored information regarding the driving sound. (Composition 3) The lens device is equipped with a lens mount for attaching it to the imaging device, The lens device according to configuration 1 or 2, characterized in that the transmission characteristic is the vibration transmission rate from the lens mount to the built-in microphone provided in the imaging device. (Composition 4) The lens device according to configuration 3, characterized in that the lens drive control unit acquires the transmission characteristics from the imaging device via the lens communication unit when the lens device is attached to the imaging device. (Composition 5) The lens device according to any one of configurations 1 to 4, characterized in that the memory unit stores the transmission characteristics. (Composition 6) The imaging device is capable of having an external microphone attached. The lens device according to any one of configurations 1 to 5, characterized in that the lens drive control unit determines the driving conditions of the optical element without using the transmission characteristics when the external microphone is used. (Composition 7) The imaging device and, An imaging system characterized by comprising a lens device according to any one of configurations 1 to 6. (Composition 8) An imaging device comprising a lens device that is detachably attached and a camera communication unit that communicates with the lens device, A camera drive control unit that drives the optical elements included in the lens device via the camera communication unit, The imaging device includes a storage unit for storing information regarding the sound transmission characteristics of the imaging device, The imaging apparatus is characterized in that the camera drive control unit determines the driving conditions of the optical element based on information relating to the driving sound of the lens device, optical information of the lens device, and information relating to the transmission characteristics. (Composition 9) The lens device is equipped with a lens mount for attaching it to the imaging device, The imaging device according to configuration 8, characterized in that the transmission characteristic is the vibration transmission rate from the lens mount to the built-in microphone provided in the imaging device. (Composition 10) An external microphone can be attached. The imaging apparatus according to configuration 8 or 9, characterized in that the camera drive control unit determines the driving conditions of the optical element without using the transmission characteristics when the external microphone is used. (Composition 11) The imaging apparatus according to configuration 10, further comprising means for estimating the sound transmission characteristics of the imaging apparatus, including the external microphone, by analyzing the sound recorded by the external microphone. (Composition 12) The lens device has a storage unit that stores information related to the drive sound and optical information, An imaging system characterized by comprising an imaging device described in any one of items 8 to 11 of the configuration. (Method 1) A control method for a lens device that is detachably attached to an imaging device and includes a lens communication unit that communicates with the imaging device, To acquire the sound transmission characteristics of the aforementioned imaging device, A method for controlling a lens device, characterized by including determining the driving conditions of an optical element based on the transmission characteristics and information regarding the driving sound when driving an optical element included in the lens device. (Method 2) Based on the aforementioned transmission characteristics, information regarding the driving sound when driving the optical elements included in the lens device, and the optical information of the lens device, the imaging device determines the driving conditions for the optical elements. A method for controlling a lens device according to Method 1, further comprising the imaging device driving the optical element based on the determined driving conditions. (Method 3) A method for controlling a lens device according to method 1 or 2, further comprising, when acquiring the aforementioned transmission characteristics, analyzing the sound recorded by an external microphone attached to the imaging device to estimate the sound transmission characteristics of the imaging device including the external microphone. [Explanation of Symbols]

[0060] 100...Lens device 101...Focus Lens 111...Lens microcontroller 1110...Lens drive control unit 120...Lens control section 200, 200-1... Imaging device 2120...Camera drive control unit 2121...Automatic focus adjustment means 2122...Voice Analysis Department 217...Camera memory 221...Built-in microphone 300····External microphone

Claims

1. A lens device that is detachably attached to an imaging device and includes a lens communication unit that communicates with the imaging device, A lens drive control unit that drives the optical elements included in the lens device, The system includes a storage unit that stores information relating to the driving sound of the optical element, The lens device is characterized in that the lens drive control unit determines the driving conditions for the optical element based on the sound transmission characteristics of the imaging device and information regarding the driving sound when driving the optical element.

2. It further includes an operating member for driving an optical element, The lens device according to claim 1, characterized in that the lens drive control unit determines the driving conditions of the optical element based on the amount of operation of the operating member, the transmission characteristics, and the stored information regarding the driving sound.

3. The lens device is equipped with a lens mount for attaching it to the imaging device, The lens device according to claim 1, characterized in that the transmission characteristic is the vibration transmission rate from the lens mount to the built-in microphone provided in the imaging device.

4. The lens device according to claim 3, characterized in that the lens drive control unit acquires the transmission characteristics from the imaging device via the lens communication unit when the lens device is attached to the imaging device.

5. The lens device according to claim 1, characterized in that the memory unit stores the transmission characteristics.

6. The imaging device is capable of having an external microphone attached. The lens device according to claim 1, characterized in that the lens drive control unit determines the driving conditions of the optical element without using the transmission characteristics when the external microphone is used.

7. The imaging device and, An imaging system comprising a lens device according to any one of claims 1 to 6.

8. An imaging device comprising a lens device that is detachably attached and a camera communication unit that communicates with the lens device, A camera drive control unit that drives the optical elements included in the lens device via the camera communication unit, The imaging device includes a storage unit for storing information regarding the sound transmission characteristics of the imaging device, The imaging apparatus is characterized in that the camera drive control unit determines the driving conditions of the optical element based on information relating to the driving sound of the lens device, optical information of the lens device, and information relating to the transmission characteristics.

9. The lens device is equipped with a lens mount for attaching it to the imaging device, The imaging device according to claim 8, characterized in that the transmission characteristic is the vibration transmission rate from the lens mount to the built-in microphone provided in the imaging device.

10. An external microphone can be attached. The imaging apparatus according to claim 8, characterized in that the camera drive control unit determines the driving conditions of the optical element without using the transmission characteristics when the external microphone is used.

11. The imaging apparatus according to claim 10, further comprising means for estimating the sound transmission characteristics of the imaging apparatus, including the external microphone, by analyzing the sound recorded by the external microphone.

12. The lens device has a storage unit that stores information related to the drive sound and optical information, An imaging system comprising an imaging device according to any one of claims 8 to 11.

13. A control method for a lens device that is detachably attached to an imaging device and includes a lens communication unit that communicates with the imaging device, To acquire the sound transmission characteristics of the aforementioned imaging device, A method for controlling a lens device, characterized by including determining the driving conditions of an optical element based on the transmission characteristics and information regarding the driving sound when driving an optical element included in the lens device.

14. Based on the aforementioned transmission characteristics, information regarding the driving sound when driving the optical elements included in the lens device, and the optical information of the lens device, the imaging device determines the driving conditions for the optical elements. The control method for a lens device according to claim 13, further comprising the imaging device driving the optical element based on the determined driving conditions.

15. The control method for a lens device according to claim 13, further comprising, when acquiring the aforementioned transmission characteristics, analyzing the sound recorded by an external microphone attached to the imaging device to estimate the sound transmission characteristics of the imaging device including the external microphone.

Images