Lens device, imaging apparatus and camera system

Abstract

To provide a lens device that can suppress vibration-proof performance deterioration due to follow-up delay at control changeover time.SOLUTION: A lens device that is the lens device which is removable from an imaging apparatus comprises: a first correction unit that performs vibration correction of the lens device by moving a first vibration-proof member; a first control unit that controls the first correction unit using first control for correcting vibration of a first frequency band at non-exposure time and second control for correcting vibration of a second frequency band which is different from the first frequency band at exposure time; and a notification unit that notifies first time up to time to start exposure to the imaging apparatus after the imaging apparatus is instructed to execute exposure.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a lens apparatus, an imaging apparatus, and a camera system. [Background technology]

[0002] Conventionally, optical devices have been known that have a function for correcting image blur caused by camera shake, and that perform control with weakened vibration isolation performance or control to keep the vibration isolation member centered during non-exposure, and control with strengthened vibration isolation performance during exposure. Patent Document 1 describes a configuration in which, after exposure starts, control is switched to one with a wider feedback control frequency band than before exposure starts. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3924890 Summary of the Invention [Problem to be solved by the invention]

[0004] When control is switched before and after exposure as in the configuration of Patent Document 1, the acceleration of the correction command value sent to the vibration isolation member changes discontinuously, causing a tracking delay in the correction command value sent to the vibration isolation member. If a tracking delay occurs during exposure, vibration isolation performance deteriorates. In particular, if the release time lag is shortened, the period during which a tracking delay occurs after control switching overlaps with the exposure period, making it easy for vibration isolation performance to deteriorate.

[0005] An object of the present invention is to provide a lens device that can suppress deterioration of image stabilization performance due to tracking delay when switching control. [Means for solving the problem]

[0006] A lens device according to one aspect of the present invention is a lens device that is detachable from an imaging device, and is characterized by having: a first correction unit that corrects shake of the lens device by moving a first vibration-damping member; a first control unit that controls the first correction unit using a first control for correcting shake in a first frequency band during non-exposure and a second control for correcting shake in a second frequency band different from the first frequency band during exposure; and a notification unit that notifies the imaging device of a first time period from when the imaging device is instructed to perform exposure until when exposure starts. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a lens device that can suppress deterioration of image stabilization performance due to tracking delay when switching control. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram of a camera system according to a first embodiment. [Figure 2] 10 is a diagram showing the tracking delay of the image stabilization lens when switching between non-exposure control and exposure control in the first embodiment. FIG. [Figure 3] 1 is a flowchart showing the processing of the camera system of the first embodiment. [Figure 4] 10 is a flowchart showing a method for setting a follow-up delay time according to the first embodiment. [Figure 5] 10 is a flowchart showing the processing of the camera system of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to designate the same components, and redundant explanations will be omitted.

[0010] [Example 1] 1 is a block diagram of a camera system (image capture system) 10 according to this embodiment. The camera system 10 includes an interchangeable lens 101 and a camera body (image capture device) 100 to which the interchangeable lens 101 is detachably and communicably connected.

[0011] The camera body 100 has a camera MPU (second control unit) 102, an operation unit 103, an image sensor (second vibration isolation member) 104, and a camera-side contact terminal 105. The camera body 100 also has a camera-side gyro sensor 106, an image sensor actuator (second correction unit) 107, an image sensor position sensor 108, and a rear display 115.

[0012] The camera MPU 102 is a controller that handles overall control of the camera body 100 and the interchangeable lens 101, and controls various operations such as AE, AF, and image capture in response to inputs from the operation unit 103. The camera MPU 102 communicates various commands and information with the lens MPU 109 via a camera-side contact terminal 105 and a lens-side contact terminal 111 provided on the interchangeable lens 101. The camera-side contact terminal 105 and the lens-side contact terminal 111 also include a power supply terminal for supplying power from the camera body 100 to the interchangeable lens 101.

[0013] The operation unit 103 includes a mode dial for setting various imaging modes, a release button for issuing instructions for imaging preparation operations and the start of imaging, and the like. Pressing the release button halfway turns on a first switch (SW1), and pressing it all the way turns on a second switch (SW2). AE and AF are performed as imaging preparation operations when SW1 is turned on, and AE settings are confirmed and AF is stopped when SW2 is turned on, and an instruction to start imaging (exposure) is issued (SW2-1 is turned on). Actual exposure begins a predetermined time after the instruction to start imaging is issued (SW2-2 is turned on). SW2-1 and SW2-2 are turned off when the set exposure time has elapsed and imaging is completed. The on / on status of SW1, SW2-1, and SW2-2 is notified to the lens MPU 109 via communication from the camera MPU 102.

[0014] The image sensor 104 is configured with a photoelectric conversion element such as a CCD sensor or a CMOS sensor, and generates an image signal by photoelectrically converting an object image formed by an image pickup optical system (described later). The camera MPU 102 generates a video signal using the image signal from the image sensor 104.

[0015] The camera-side gyro sensor 106 is a shake sensor that detects angular shake (camera shake) of the camera body 100 due to hand shake or the like and outputs a camera shake detection signal as an angular velocity signal. The camera MPU 102 drives the image sensor actuator 107 based on the camera shake detection signal to move the image sensor 104 in a direction that includes a component perpendicular to the optical axis of the imaging optical system (described later). This reduces (corrects) image shake due to camera shake. At this time, the camera MPU 102 performs feedback control of the image sensor actuator 107 so that the position of the image sensor 104 (the amount of movement from a position on the optical axis that is the center of movement) detected by the image sensor position sensor 108 approaches a target position. This performs image shake correction (hereinafter referred to as IBIS) by moving the image sensor 104. Note that IBIS is performed for camera shake in the up-down direction (pitch direction) and the left-right direction (yaw direction).

[0016] The rear display 115 displays an image corresponding to a video signal generated by the camera MPU 102 using an imaging signal from the imaging element 104. Before capturing an image, the user can observe the displayed image as a viewfinder image (live view image). After capturing an image, a still image or video for recording generated by capturing an image can be displayed on the rear display 115. In this embodiment, "capturing an image" refers to capturing an image for recording.

[0017] The interchangeable lens 101 has an imaging optical system including an image stabilization lens (first vibration isolation member) 113, a lens MPU 109, a lens side gyro sensor 110, a lens side contact terminal 111, a lens actuator (first correction unit) 112, and a lens position sensor 114.

[0018] The lens-side gyro sensor 110 is a shake sensor that detects angular shake (lens shake) of the interchangeable lens 101 and outputs a lens shake detection signal as an angular velocity signal.

[0019] The lens MPU 109 drives the lens actuator 112 based on the lens shake detection signal to move the image stabilization lens 113 in a direction that includes a component orthogonal to the optical axis of the imaging optical system. This reduces (corrects) image shake caused by lens shake. At this time, the lens MPU 109 performs feedback control of the lens actuator 112 so that the position of the image stabilization lens 113 detected by the lens position sensor 114 (the amount of movement from a position on the optical axis that is the center of movement) approaches a target position. In this way, image stabilization (hereinafter referred to as OIS) is performed by moving the image stabilization lens 113.

[0020] The following describes a tracking delay of the image stabilization lens 113 when switching between non-exposure control (first control) and exposure control (second control), which is a problem of the present invention. The lens MPU 109 functions as a first control unit that controls the lens actuator 112 using non-exposure control and exposure control and performs vibration reduction control. FIG. 2 is a diagram showing the tracking delay of the image stabilization lens 113 when switching between non-exposure control and exposure control. Non-exposure control is control that weakens the vibration reduction performance (image stabilization performance) performed during non-exposure, or control that keeps the vibration reduction member centered without performing vibration reduction control, and is used to correct lens shake in a first frequency band. Exposure control is control that strengthens the vibration reduction performance performed during exposure, and is used to correct lens shake in a second frequency band different from the first frequency band. In other words, non-exposure control and exposure control have different vibration reduction frequency bands.

[0021] In non-exposure control, a low-pass filter is applied to the lens shake detection signal to remove low-frequency components of lens shake, and then image stabilization (image shake correction) is performed. By performing image stabilization for lens shake in the mid- to high-frequency band, the image stabilization lens 113 is less likely to collide with the movable end. Furthermore, with this type of control, when the user aims while looking at the EVF, lens shake caused by intentional changes in the angle of view is not stabilized, and only lens shake in the high-frequency band is stabilized, making aiming easy.

[0022] In exposure control, in order to prevent the captured photograph from being blurred due to lens shake in the low frequency band, a low-pass filter is not applied, or a low-pass filter with a low cutoff frequency is applied, thereby performing vibration reduction including lens shake in the lower frequency band.

[0023] L1 is the target command value (target position) for the image stabilization lens 113 when switching from non-exposure control to exposure control. During non-exposure control, a strong low-pass filter is applied, resulting in a target command value that gradually moves toward the center while still correcting lens shake in the high-frequency band. On the other hand, during exposure control, lens shake in the low-frequency band is reflected in the target command value. Therefore, when control is switched, the acceleration of the target command value changes discontinuously. L2 is the actual position of the image stabilization lens 113. When the acceleration changes discontinuously during control switching, the image stabilization lens 113 cannot track the target command value, and it takes time for the actual position to catch up with the target command value. While the target command value L1 and the actual position L2 differ, image stabilization is not performed correctly, and if exposure were to occur during this time, the captured image would be blurred.

[0024] FIG. 3 is a flowchart showing the processing of the camera system 10 of this embodiment.

[0025] In step S301, the camera MPU 102 notifies the lens MPU 109 of the start of exposure control the moment the release button is pressed.

[0026] In step S302, the lens MPU 109 notifies the camera MPU 102 of the tracking delay time (first time). The lens MPU 109 functions as a notification unit that notifies the tracking delay time, and the camera MPU 102 functions as an acquisition unit that acquires the tracking delay time. The tracking delay time is the time from when the camera MPU 102 is instructed to perform exposure until the timing (time) at which exposure starts. For example, it is the time from when the control of the lens actuator is switched from non-exposure control to exposure control until the tracking delay of the image stabilization lens 113 relative to the target command value subsides. A specific method for setting the tracking delay time will be described later. The tracking delay time may be notified immediately after the camera system is started, or may be notified periodically.

[0027] In step S303, the lens MPU 109 receives a notification from the camera MPU 102 to start exposure control, and switches the OIS from non-exposure control to exposure control.

[0028] In step S304, the camera MPU 102 waits for the tracking delay time received from the lens MPU 109 in step S302 from the timing at which the exposure control start notification was sent to the lens MPU 109 in step S301, and then starts exposure. Note that the timing at which the exposure control start notification was sent to the lens MPU 109 in step S301 is assumed to be the same as the timing at which the OIS was switched from non-exposure control to exposure control. Here, "same" not only includes being strictly identical, but also being substantially identical (almost identical).

[0029] By performing the above-described control, the camera MPU 102 can minimize the release time lag after waiting for the tracking delay time specific to the lens model.

[0030] FIG. 4 is a flowchart showing a method for setting the follow-up delay time.

[0031] In step S401, the lens MPU 109 determines whether or not vibration compensation control is being performed. If the lens MPU 109 determines that vibration compensation control is being performed, it executes the process of step S402. If the lens MPU 109 determines that vibration compensation control is not being performed, it executes the process of step S405. For example, vibration compensation control is stopped when the IS (vibration compensation) switch is off, when panning is being performed, or when tripod photography is being performed. If vibration compensation control is stopped (when the lens actuator 112 has stopped the image stabilization lens 113), control switching is not performed, and therefore no tracking delay occurs. Therefore, in order to shorten the release time lag, in step S405, the lens MPU 109 sets the tracking delay time to 0 [seconds].

[0032] In step S402, the lens MPU 109 determines whether the exposure time is equal to or less than a threshold value. If the lens MPU 109 determines that the exposure time is equal to or less than the threshold value, it executes the process of step S403. If the lens MPU 109 determines that the exposure time is not equal to or less than the threshold value, it executes the process of step S405. If the exposure time is long, the effect of lens shake due to tracking delay becomes small. Therefore, in order to shorten the release time lag, in step S405, the lens MPU 109 sets the tracking delay time to 0 [seconds].

[0033] In step S403, the lens MPU 109 sets a tracking delay time specific to the lens model. The tracking delay time when switching control depends heavily on the lens model. For example, models with a heavy image stabilization lens 113 or models with a weak lens actuator 112 tend to have a long tracking delay. For this reason, it is necessary to set a tracking delay time for each lens model.

[0034] In step S404, the lens MPU 109 corrects (adjusts, sets) the tracking delay time according to the amount of change in acceleration of the target command value for the image stabilization lens 113 (the amount of change in acceleration of the image stabilization lens 113). For example, if the difference between non-exposure control and exposure control is small and the amount of change in acceleration is small, the tracking delay also becomes small. In such a case, the tracking delay time is corrected to be shorter, thereby further shortening the release time lag. On the other hand, if the amount of change in acceleration is large, the tracking delay time can be corrected to be longer.

[0035] In step S405, the lens MPU 109 sets the tracking delay time to 0 [seconds] as described above.

[0036] As described above, the configuration of this embodiment can suppress the deterioration of image stabilization performance due to a tracking delay when control is switched to exposure control, and can shorten the release time lag.

[0037] [Example 2] In the first embodiment, a case where image stabilization is performed using only the OIS is described, but in this embodiment, a case where image stabilization is performed by coordinating the IBIS and the OIS is described. The basic configuration of the camera system of this embodiment is the same as that of the camera system 10 of the first embodiment. In this embodiment, only the configuration different from that of the first embodiment is described.

[0038] In this embodiment, the camera MPU 102 controls the image sensor actuator 107 using non-exposure control (third control) and exposure control (fourth control). The non-exposure control (third control) is a control that weakens the vibration isolation performance performed during non-exposure, or a control that keeps the vibration isolation member centered without performing vibration isolation control, and is used to correct lens shake in the third frequency band. The exposure control (fourth control) is a control that strengthens the vibration isolation performance performed during exposure, and is used to correct lens shake in a fourth frequency band that is different from the third frequency band. In other words, the non-exposure control (third control) and the exposure control (fourth control) have different vibration isolation frequency bands.

[0039] FIG. 5 is a flowchart showing the processing of the camera system 10 of this embodiment.

[0040] In step S501, the camera MPU 102 notifies the lens MPU 109 of the start of exposure control the moment the release button is pressed.

[0041] In step S502, the lens MPU 109 notifies the camera MPU 102 of the tracking delay time.

[0042] In step S503, the camera MPU 102 starts exposure control of the IBIS.

[0043] In step S504, the lens MPU 109 starts exposure control of the OIS.

[0044] In step S505, the camera MPU 102 starts exposure after waiting for the IBIS tracking delay time (second time) that corresponds to the OIS tracking delay time and the camera body 100. The IBIS tracking delay time is set in the same manner as described with reference to FIG.

[0045] As described above, the configuration of this embodiment can suppress the deterioration of image stabilization performance due to a tracking delay when control is switched to exposure control, and can shorten the release time lag.

[0046] The disclosure of this embodiment includes the following configuration. (Configuration 1) A lens device that is detachable from an imaging device, a first correction unit that corrects shake of the lens device by moving a first vibration isolation member; a first control unit that controls the first correction unit using a first control for correcting a vibration in a first frequency band during non-exposure and a second control for correcting a vibration in a second frequency band different from the first frequency band during exposure; A lens device comprising: a notification unit that notifies the imaging device of a first time period from when the imaging device is instructed to perform exposure until the exposure starts. (Configuration 2) The lens device described in configuration 1, characterized in that the first time period is the time from when the control of the first correction unit is switched from the first control to the second control to when the tracking delay of the first vibration isolation member with respect to the target position subsides. (Configuration 3) 3. The lens device according to configuration 1 or 2, wherein the first time period is set to a value specific to the lens device. (Configuration 4) The lens device according to any one of configurations 1 to 3, wherein the first time is set to 0 seconds when the first correction unit stops the first vibration isolation member. (Configuration 5) 5. The lens device according to any one of configurations 1 to 4, wherein the first time is set to 0 seconds if the exposure time is equal to or greater than a threshold value. (Configuration 6) The lens device described in any one of configurations 1 to 5, characterized in that the first time period is set to a longer time as the amount of change in acceleration of the first vibration-isolating member caused by switching the control of the first correction unit from the first control to the second control increases. (Configuration 7) An imaging device to which the lens device according to any one of configurations 1 to 6 can be attached / detached, an acquisition unit that acquires the first time from the notification unit; and a second control unit that starts exposure when the first time period has elapsed after execution of exposure is instructed. (Configuration 8) a second correction unit that corrects shake of the lens device by moving a second vibration-isolating member; the second control unit controls the second correction unit using a third control for correcting a vibration in a third frequency band during non-exposure and a fourth control for correcting a vibration in a fourth frequency band different from the third frequency band during exposure, The imaging device described in configuration 7, wherein the second control unit starts the exposure after the first time and a second time, which is the time until the timing to start the exposure after the imaging device is instructed to perform the exposure, have elapsed. (Configuration 9) 9. The imaging device according to configuration 8, wherein the second time is set to a value specific to the imaging device. (Configuration 10) a lens device according to any one of configurations 1 to 6; A camera system comprising the imaging device according to configuration 7.

[0047] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0048] 100 Camera body (imaging device) 101 Interchangeable lenses (lens devices) 109 Lens MPU (first control unit, notification unit) 112 Lens actuator (first correction unit) 113 Image stabilization lens (first vibration-proof member)

Claims

1. A lens device that is detachable from an imaging device, a first correction unit that corrects shake of the lens device by moving a first vibration isolation member; a first control unit that controls the first correction unit using a first control for correcting a vibration in a first frequency band during non-exposure and a second control for correcting a vibration in a second frequency band different from the first frequency band during exposure; A lens device comprising: a notification unit that notifies the imaging device of a first time period from when the imaging device is instructed to perform exposure until the exposure starts.

2. 2. The lens device according to claim 1, wherein the first time period is a time period from when the control of the first correction unit is switched from the first control to the second control to when a tracking delay of the first vibration isolation member relative to the target position subsides.

3. 3. The lens device according to claim 1, wherein the first time period is set to a value specific to the lens device.

4. 3. The lens device according to claim 1, wherein the first time period is set to 0 seconds when the first correction unit stops the first vibration isolation member.

5. 3. The lens device according to claim 1, wherein the first time is set to 0 seconds when the exposure time is equal to or greater than a threshold value.

6. The lens device according to claim 1 or 2, characterized in that the first time period is set to a longer time as the amount of change in acceleration of the first vibration-damping member due to the control of the first correction unit being switched from the first control to the second control increases.

7. An imaging device to which the lens device according to claim 1 or 2 can be detachably attached, an acquisition unit that acquires the first time from the notification unit; and a second control unit that starts exposure when the first time period has elapsed after execution of exposure is instructed.

8. a second correction unit that corrects shake of the lens device by moving a second vibration-isolating member; the second control unit controls the second correction unit using a third control for correcting a shake in a third frequency band during non-exposure and a fourth control for correcting a shake in a fourth frequency band different from the third frequency band during exposure, 8. The imaging device according to claim 7, wherein the second control unit starts the exposure after the first time and a second time, which is a time until the timing to start the exposure after the imaging device is instructed to perform the exposure, have elapsed.

9. 9. The imaging device according to claim 8, wherein the second time is set to a value specific to the imaging device.

10. The lens device according to claim 1 or 2; A camera system comprising the imaging device according to claim 7.

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