JP2020201451A - Imaging apparatus and method for controlling imaging apparatus - Google Patents

Abstract

To provide an imaging apparatus that prevents a reduction in the accuracy of shake correction due to bending of an interchangeable lens.SOLUTION: An imaging apparatus is removably attached with a lens device having an imaging optical system and a first vibration detection unit, and comprises: an image pick-up device that picks up an image formed by light beams transmitting through the imaging optical system; a second vibration detection unit; and an adjustment unit that calculates a shake correction signal based on at least one of a first signal output from the first vibration detection unit and a second signal output from the second vibration detection unit, and outputs the shake correction signal to shake correction means that executes shake correction during imaging. The distance from a principal point in the imaging optical system in the direction of the optical axis of the imaging optical system is shorter in the first vibration detection unit than that in the second vibration detection unit. The adjustment unit changes a reference ratio for referring to the first signal and the second signal in calculating the shake correction signal according to an imaging condition.SELECTED DRAWING: Figure 2

Description

The present invention relates to an image pickup apparatus and a control method for the image pickup apparatus.

Regarding camera shake correction of a camera system in which an interchangeable lens is attached to a camera body, there is known a technique for driving, for example, a blur correction unit mounted on an interchangeable lens based on a signal of a vibration detection unit mounted on the camera body. (See Patent Document 1).

Japanese Unexamined Patent Publication No. 2007-52235

As an example, when a mechanical shutter in the camera body is driven at the start of exposure at the time of capturing a still image in a camera system (mechanical front curtain drive), high-frequency vibration is generated with the operation of the mechanical shutter. Then, the vibration causes a minute bending in the interchangeable lens connected to the camera body. If an error occurs in the vibration detection result between the vibration detection unit of the camera body and the vibration detection unit of the interchangeable lens due to such bending or the like, the blur correction accuracy of the camera system may decrease.

The present invention has been made in view of the above circumstances, and provides an imaging device that suppresses a decrease in blur correction accuracy due to bending of an interchangeable lens or the like.

An example of the present invention is an image pickup device in which a lens device having an image pickup optical system and a first vibration detection unit can be attached and detached. The image pickup device is an image pickup element that captures an image of a luminous flux passing through an imaging optical system, a second vibration detection unit, and outputs from a first signal and a second vibration detection unit output from the first vibration detection unit. A blur correction unit that calculates a blur correction signal based on at least one of the second signals and outputs a blur correction signal to a blur correction means that executes blur correction at the time of imaging is provided. The distance from the principal point of the imaging optical system in the optical axis direction of the imaging optical system is shorter in the first vibration detection unit than in the second vibration detection unit, and the adjustment unit calculates the blur correction signal. The reference ratio for referring to the first signal and the second signal is changed according to the imaging conditions.

According to the image pickup apparatus which is an example of the present invention, it is possible to suppress a decrease in blur correction accuracy due to bending of the interchangeable lens or the like.

It is a figure which shows the configuration example of the camera system of 1st Embodiment. It is a figure which shows typically the state which the interchangeable lens is bent. It is a figure which shows the control example of the blur correction in 1st Embodiment. It is a figure explaining the calculation example of the angle change amount in consideration of the position change of the principal point P. It is a figure which shows the control example of blur correction in 2nd Embodiment. It is a figure which shows the structural example of the adjustment part in 3rd Embodiment. It is a figure which shows the example of the characteristic of the high-pass filter (HPF) and the low-pass filter (LPF) in the 3rd Embodiment. It is a figure which shows the change control example of the characteristic of the high-pass filter and the low-pass filter in the 3rd Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to drawings and the like.

<First Embodiment>
FIG. 1 is a diagram showing a configuration example of the camera system of the first embodiment. The camera system 11 includes a camera body 11a and an interchangeable lens 11b that can be attached to and detached from the camera body 11a. The camera body 11a is an example of an image pickup apparatus, and the interchangeable lens 11b is an example of a lens apparatus.

The camera body 11a includes a body CPU (Central Processing Unit) 12a, an image sensor 14, an adjustment unit 16, a second vibration detection unit 17, a second drive unit 19, and a mechanical shutter (hereinafter, simply a shutter). Includes 30).
On the other hand, the interchangeable lens 11b includes a lens CPU 12b, an imaging optical system 13, a first vibration detection unit 15, and a first drive unit 18.

The body CPU 12a is a processor responsible for controlling the camera body 11a side, and the lens CPU 12b is a processor responsible for controlling the interchangeable lens 11b side. When the interchangeable lens 11b is attached to the camera body 11a, the body CPU 12a and the lens CPU 12b communicate with each other, and both of them cooperate to control the camera system 11 at the time of imaging.

First, the components of the interchangeable lens 11b will be described.
In the camera system 11, the luminous flux from the subject passes through the image pickup optical system 13 of the interchangeable lens 11b and is incident on the image pickup element 14 of the camera body 11a. Further, the imaging optical system 13 may have a zoom optical system. In the drawing showing the camera system 11, the optical axis of the camera system 11 is indicated by reference numeral 10, and the position of the principal point of the imaging optical system 13 is indicated by a point P.

Some lenses included in the imaging optical system 13 of the interchangeable lens 11b function as the first blur correction unit 13a, which is one of the blur correction means. The lens constituting the first blur correction unit 13a is moved by the first drive unit 18 in a plane orthogonal to the optical axis 10. By driving the first blur correction unit 13a, it is possible to correct the image blur that occurs on the image pickup surface of the image pickup device 14 due to the blur of the camera system 11.
Here, as the drive mechanism of the first drive unit 18, for example, a linear actuator such as a voice coil motor (VCM) or a stepping motor combined with a lead screw can be used. In the drawing showing the camera system 11, a part of the moving direction of the first blur correction unit 13a (vertical direction in the figure) is indicated by an arrow 13b, but the first blur correction unit 13a is in the paper depth direction in the drawing. You can also move to.

The first vibration detection unit 15 is a gyro sensor arranged inside the interchangeable lens 11b, and detects the angular velocity of blur in each direction of the camera system 11. The signal of the first vibration detection unit 15 (also referred to as the first signal) is output to the adjustment unit 16 of the camera body 11a.

Subsequently, the components of the camera body 11a will be described.
The image sensor 14 captures an image of the subject by the light flux passing through the image pickup optical system 13 and outputs an image signal. The image signal output from the image sensor 14 is generally image-processed by an image processing unit (not shown) provided on the camera body 11a, and then recorded in a storage unit (not shown).

Further, the image sensor 14 functions as a second blur correction unit 14a, which is one of the blur correction means. The image sensor 14 is moved by the second drive unit 19 in a plane orthogonal to the optical axis 10. By driving the image sensor 14, it is possible to correct the image blur that occurs on the image pickup surface of the image sensor 14 due to the blur of the camera system 11.
In the drawing showing the camera system 11, a part of the moving direction of the second blur correction unit 14a (vertical direction in the figure) is indicated by an arrow 14b, but the second blur correction unit 14a is in the paper depth direction in the drawing. You can also move to.

The shutter 30 is arranged on the front surface of the image pickup device 14 on the subject side, and mechanically controls the incident of light on the image pickup surface of the image pickup device 14 mainly during still image imaging.
For example, when the camera system 11 captures a still image, the front curtain of the shutter 30 is first driven to close, and the image sensor 14 resets the charge of the pixels. Subsequently, the front curtain of the shutter 30 is driven to open. As a result, light is incident on the image sensor 14 and exposure is started. After that, the rear curtain of the shutter 30 is driven to close. As a result, the image sensor 14 is shielded from light and the exposure is completed, and the electric charge is read out from each pixel of the image sensor 14 to obtain an image signal.

The second vibration detection unit 17 is a gyro sensor arranged in the camera body 11a, and detects the angular velocity of the shake in each direction of the camera system 11 like the first vibration detection unit 15. The second vibration detection unit 17 is arranged at a position far from the principal point P of the imaging optical system 13 in the optical axis direction as compared with the first vibration detection unit 15 arranged on the interchangeable lens 11b. The signal of the second vibration detection unit 17 (also referred to as the second signal) is output to the adjustment unit 16 in the same manner as the signal of the first vibration detection unit 15.
In the camera system 11, the first vibration detection unit 15 and the second vibration detection unit 17 may be arranged together in either the interchangeable lens 11b or the camera body 11a.

The adjusting unit 16 is controlled by either the body CPU 12a or the lens CPU 12b, and calculates the amount of angle change as blur information of the camera system 11. The adjusting unit 16 calculates the above-mentioned angle change amount by integrating the angular velocities with reference to the signals of the first vibration detecting unit 15 and the second vibration detecting unit 17 in combination by the method described later.
Further, the adjusting unit 16 generates a blur correction signal for correcting the calculated angle change amount. Then, the adjusting unit 16 transmits the generated blur correction signal to the first driving unit 18 for driving the first blur correction unit 13a or the second driving unit 19 for driving the second blur correction unit 14a. Sort and output. As a result, blur correction of the camera system 11 is executed.

Here, an example of the output distribution of the blur correction signal to the first drive unit 18 or the second drive unit 19 by the adjustment unit 16 will be described.

In general, the first blur correction unit 13a on the interchangeable lens 11b side is characterized in that it is easier to secure a larger amount of blur correction than the second blur correction unit 14a on the camera body 11a side.
Since the second blur correction unit 14a uses the image sensor 14 for blur correction, the blur correction amount is determined by the movement amount of the image sensor 14. Therefore, if an attempt is made to increase the amount of blur correction of the second blur correction unit 14a, the space around the image sensor 14 becomes large, and the camera body 11a becomes large. On the other hand, the first blur correction unit 13a, which uses a part of the imaging optical system 13 for blur correction, sets a high power of the lens group for correction to increase the optical sensitivity, so that the blur is blurred even with the same drive amount. The amount of correction can be made larger. For the above reasons, the first blur correction unit 13a tends to increase the blur correction amount more than the second blur correction unit 14a.

On the other hand, the first blur correction unit 13a cannot correct the image blur in the rotation direction about the optical axis 10 as the central axis, while the second blur correction unit 14a using the image sensor 14 for blur correction rotates. It has the feature that it can correct the image blur in the direction.

Further, in general, the longer the focal length of the imaging optical system 13, the larger the image blur amount for the same blur amount of the camera system 11. Therefore, when the focal length of the imaging optical system 13 is long, it is important to secure a large amount of blur correction as compared with the case where the focal length is short. On the other hand, as the focal length of the imaging optical system 13 becomes shorter, the ratio of the amount of blurring in the rotation direction to the amount of image blurring increases. Therefore, when the focal length of the imaging optical system 13 is short, it is important to correct the image blur in the rotation direction as compared with the case where the focal length is long.

From the above viewpoint, the body CPU 12a (or the lens CPU 12b) detects the imaging conditions of the camera system 11 and controls the adjusting unit 16 as follows according to the imaging conditions.

For example, the body CPU 12a (or the lens CPU 12b) blurs the adjusting unit 16 so that the longer the focal length of the imaging optical system 13 is, the larger the blur correction is performed on the first drive unit 18 than on the second drive unit 19. Controls the output of the correction signal. For example, the body CPU 12a (or the lens CPU 12b) blurs the adjusting unit 16 so that as the focal length of the imaging optical system 13 becomes shorter, the second drive unit 19 blurs more than the first drive unit 18. Controls the output of the correction signal.

Further, the body CPU 12a (or the lens CPU 12b) may control the adjusting unit 16 based on a preset focal length threshold value. For example, the body CPU 12a (or the lens CPU 12b) may be controlled so that the adjusting unit 16 outputs all the blur correction signals to the first driving unit 18 when the focal length is longer than the threshold value. Further, the body CPU 12a (or the lens CPU 12b) may be controlled so that the adjusting unit 16 outputs all the blur correction signals to the second driving unit 19 when the focal length is equal to or less than the threshold value.

Next, a method of combining the signals of the first vibration detection unit 15 and the second vibration detection unit 17 by the adjustment unit 16 will be described.
In the first embodiment, when the exposure time is short among the imaging conditions of the camera system 11, the adjusting unit 16 calculates the blur information of the camera system 11 mainly based on the signal of the first vibration detecting unit 15. On the other hand, when the exposure time is long, the adjusting unit 16 calculates the blur information of the camera system 11 mainly based on the signal of the second vibration detecting unit 17. The reason will be described with reference to FIG.

FIG. 2 is a diagram schematically showing a state in which the interchangeable lens 11b is bent with respect to the camera body 11a.
As described above, when the shutter 30 in the camera body 11a is driven by the mechanical front curtain drive at the time of capturing a still image by the camera system 11, high-frequency vibration is generated in the camera body 11a. Then, the vibration is transmitted to the interchangeable lens 11b connected to the camera body 11a, so that the interchangeable lens 11b is slightly bent with respect to the camera body 11a for a certain period of time.

Here, in a normal state (FIG. 1) in which the above bending does not occur, between the first vibration detection unit 15 on the interchangeable lens 11b side and the second vibration detection unit 17 on the camera body 11a side. , The directions of the coordinate axes that detect the angular velocity match well. However, in the state shown in FIG. 2, due to the above bending, the direction of the coordinate axes for detecting the angular velocity is deviated between the first vibration detection unit 15 and the second vibration detection unit 17. Therefore, an error occurs in each output signal of the first vibration detection unit 15 and the second vibration detection unit 17 for a certain period from immediately after the start of capturing the still image.
In FIG. 2, the orientation of the coordinate axes of the first vibration detection unit 15 is indicated by reference numeral 21, and the orientation of the coordinate axes of the second vibration detection unit 17 is indicated by reference numeral 22. Note that, in FIG. 2, with respect to the coordinate axes indicated by reference numerals 21 and 22, the axes extending in the depth direction of the paper surface are not shown.

Here, the change in the optical axis 10 due to the blurring of the camera system 11 is mainly determined by the inclination of the optical axis 10 at the position of the principal point P of the imaging optical system 13. Therefore, when correcting the blur of the camera system 11, if the blur information of the camera system 11 is calculated based on the signal of the first vibration detection unit 15 arranged at a position closer to the principal point P, the blur with higher accuracy is obtained. You can make corrections.

Further, the influence of the detection error between the vibration detection units as described above on the accuracy of the blur correction increases with the ratio of the time when the detection error occurs to the exposure time. That is, the shorter the exposure time, the greater the influence of the detection error between the vibration detection units on the accuracy of the blur correction. Therefore, it is preferable that the body CPU 12a (or the lens CPU 12b) controls the adjustment unit 16 to increase the ratio of referring to the first signal of the first vibration detection unit 15 as the exposure time under the imaging conditions becomes shorter. ..

On the other hand, low frequency noise is superimposed on each signal of the first vibration detection unit 15 and the second vibration detection unit 17 by the gyro sensor. The amount of change in angle as blur information of the camera system 11 is the integration result of the angular velocity detected by the vibration detection unit.
Therefore, the longer the exposure time, the larger the error in the amount of angle change, and the accuracy of blur correction tends to decrease.

Further, there are various types of interchangeable lenses 11b attached to the camera body 11a. For example, in the interchangeable lens 11b, the low-frequency noise of the first vibration detection unit 15 is larger than the same low-frequency noise of the second vibration detection unit 17 on the camera body 11a side because the manufacturing age is old. It can be large.

From the viewpoint of realizing stable camera shake correction in more shooting scenes, the smaller the influence of the detection error between the vibration detection units on the accuracy of the blur correction, the smaller the influence of the second vibration detection unit 17 on the accuracy of the blur correction. It is advisable to increase the ratio of referring to the second signal. That is, it is preferable that the body CPU 12a (or the lens CPU 12b) controls the adjustment unit 16 to increase the ratio of referring to the second signal of the second vibration detection unit 17 as the exposure time under the imaging conditions increases. ..

Further, the body CPU 12a (or the lens CPU 12b) may determine a vibration detection unit that refers to a signal based on a preset threshold value of the exposure time (for example, a shutter speed of 1/60 second). For example, in the body CPU 12a (or lens CPU 12b), when the exposure time is less than the threshold value, the adjusting unit 16 does not refer to the second signal of the second vibration detecting unit 17, and the first vibration detecting unit 15 does not refer to the second signal. It may be controlled to refer to all one signal. Further, in the body CPU 12a (or lens CPU 12b), when the exposure time exceeds the threshold value, the adjusting unit 16 does not refer to the first signal of the first vibration detecting unit 15, and the second vibration detecting unit 17 does not refer to the first signal. It may be controlled to refer to all two signals.

FIG. 3 is a diagram showing a control example of blur correction in the first embodiment.
The process shown in FIG. 3 starts when the camera system 11 accepts the user's shooting preparation operation (for example, when the release switch is half-pressed). Then, the process shown in FIG. 3 loops according to a predetermined control cycle (for example, the operation cycle of the body CPU 12a or the lens CPU 12b), and ends according to the end of shooting (end of exposure time, release of release switch, etc.). .. Unless otherwise specified, the body CPU 12a shall perform various determinations and controls in the processing shown in FIG.

In step S300, the body CPU 12a acquires information on the imaging conditions (exposure time, focal length, etc.) of the camera system 11 to be referred to in the subsequent control.
In step S301, the body CPU 12a determines whether the exposure time is short. As an example, the body CPU 12a determines that the exposure time is short when the acquired exposure time is 1/60 second or more of the shutter speed. When it is determined that the exposure time is short, the process shifts to step S302, and when it is not determined that the exposure time is short, the process shifts to step S303.

In step S302, the body CPU 12a controls the adjustment unit 16 to increase the ratio of referring to the signal of the first vibration detection unit 15.
For example, the body CPU 12a sets the weighting coefficient A to be multiplied by the signal of the first vibration detection unit 15 to be larger than the weighting coefficient B to be multiplied by the signal of the second vibration detection unit 17 (A> B). Here, it is assumed that the sum of the coefficient A and the coefficient B is set to 1. Further, the coefficient A may be set so as to increase as the exposure time becomes shorter.
The body CPU 12a may be controlled so that the adjusting unit 16 does not refer to the signal of the second vibration detecting unit 17, but refers to all the signals of the first vibration detecting unit 15.

The adjustment unit 16 in step S302 is an angle from the sum of the integration result of the signal of the first vibration detection unit 15 multiplied by the coefficient A and the integration result of the signal of the first vibration detection unit 15 multiplied by the coefficient B. Calculate the amount of change. According to step S302, the amount of angle change calculated when the exposure time is short is greatly affected by the detection result by the first vibration detection unit 15 on the interchangeable lens 11b side. After that, the process proceeds to step S304.

In step S303, the body CPU 12a controls the adjustment unit 16 to increase the ratio of referring to the signal of the second vibration detection unit 17.
For example, the body CPU 12a sets the weighting coefficient B to be multiplied by the signal of the second vibration detection unit 17 to be larger than the weighting coefficient A to be multiplied by the signal of the first vibration detection unit 15 (B> A). Here, it is assumed that the sum of the coefficient A and the coefficient B is set to 1. Further, the coefficient B may be set so as to increase as the exposure time becomes longer.
The body CPU 12a may be controlled so that the adjusting unit 16 does not refer to the signal of the first vibration detecting unit 15 but refers to all the signals of the second vibration detecting unit 17. As described above, the control of the ratio of referring to the signal of the first vibration detection unit 15 and the ratio of referring to the signal of the second vibration detection unit 17 also includes setting one ratio to 0.

The adjustment unit 16 in step S303 is an angle from the sum of the integration result of the signal of the first vibration detection unit 15 multiplied by the coefficient A and the integration result of the signal of the first vibration detection unit 15 multiplied by the coefficient B. Calculate the amount of change. According to step S303, the amount of angle change calculated when the exposure time is long is greatly affected by the detection result by the second vibration detection unit 17 on the camera body 11a side. After that, the process proceeds to step S304.

In step S304, the body CPU 12a determines whether the focal length is short. As an example, when the acquired focal length is shorter than the focal length under a predetermined condition (for example, when the focal length is 50 mm or less in a camera capable of capturing a screen size of 36 × 24 mm), the body CPU 12a states that the focal length is short. to decide.
When it is determined that the focal length is short, the process shifts to step S305, and when it is not determined that the focal length is short, the process shifts to step S306.

In step S305, the body CPU 12a sets the second blur correction unit 14a (second drive unit 19) as the output destination of the blur correction signal of the adjustment unit 16. After that, the process proceeds to step S307.
The body CPU 12a in step S305 outputs a blur correction signal to each drive unit so that the adjustment unit 16 corrects the blur in the second drive unit 19 at a higher rate than the first drive unit 18. It may be set.

In step S306, the body CPU 12a sets the first blur correction unit 13a (first drive unit 18) as the output destination of the blur correction signal of the adjustment unit 16. After that, the process proceeds to step S307.
The body CPU 12a in step S306 is set so that the adjusting unit 16 outputs a blur correction signal to each drive unit so that the first drive unit 18 is corrected for blurring at a higher rate than the second drive unit 19. You may.

In step S307, the adjusting unit 16 outputs a blur correction signal for correcting the above-mentioned angle change amount to the first driving unit 18 or the second driving unit 19 based on the setting in step S305 or step S306. As a result, blur correction is executed in the first blur correction unit 13a or the second blur correction unit 14a.

In step S308, the body CPU 12a determines whether or not the shooting is completed. For example, the body CPU 12a determines that the shooting is finished when the exposure time is finished or when the release switch is detected to be released. When the shooting is finished, the process of FIG. 3 is finished. On the other hand, when the shooting is not completed, the process returns to step S300, and the body CPU 12a repeats the above operation.

As described above, in the blur correction in the first embodiment, the reference ratio between the detection result of the first vibration detection unit 15 on the interchangeable lens 11b side and the detection result of the second vibration detection unit 17 on the camera body 11a side. Is changed according to the imaging conditions (exposure time). As a result, it is possible to suppress a decrease in accuracy of blur correction due to a change in imaging conditions.

By the way, in the example of FIG. 1, the first vibration detection unit 15 has been described on the premise that it is arranged in the vicinity of the main point P of the imaging optical system 13. However, depending on the type of the interchangeable lens 11b, the position of the principal point P of the imaging optical system 13 may move with various zoom and focus operations, and the positional relationship between each vibration detection unit and the principal point P may change. .. In such a case, the reference ratio between the detection result of the first vibration detection unit 15 and the detection result of the second vibration detection unit 17 may be changed based on the distance between each vibration detection unit and the principal point P. preferable.

FIG. 4 is a diagram illustrating a calculation example of an angle change amount in consideration of a position change of the principal point P. As shown in FIG. 4, the distance from the first vibration detection unit 15 to the principal point P of the imaging optical system 13 is P1, and the distance from the second vibration detection unit 17 to the principal point P of the imaging optical system 13 is defined as P1. Let it be P2. Further, the output of the first vibration detection unit 15 is V1, and the output of the second vibration detection unit 17 is V2.
At this time, the adjusting unit 16 may refer to the output V obtained by the following equation (1) as the angular velocity of the camera system 11 and calculate the amount of angular change as the blur information.
V = V1 * (P2 / (P1 + P2)) + V2 * (P1 / (P1 + P2)) ... (1)

Further, the information of P1 and P2 by various zoom and focus operations can be stored as a reference table in, for example, a memory unit (not shown) in the interchangeable lens 11b. Then, by communicating between the lens CPU 12b and the body CPU 12a, the values of P1 and P2 can be used as known values. Further, it is not necessary to directly hold the values of P1 and P2, and only one type of calculation result (dimensionless quantity) of the coefficient of V1 in the above equation (1) may be held.
Since the accuracy of these values is sufficient, for example, about 4 bits, the load on the communication band and computational resources of the camera system 11 can be kept small.

<Second Embodiment>
In the second embodiment, an example in which the reference ratio between the detection result of the first vibration detection unit 15 and the detection result of the second vibration detection unit 17 is changed according to the focal length will be described.
The flexibility of the interchangeable lens 11b with respect to the camera body 11a is greatly related to the overall length and rigidity of the interchangeable lens 11b, but these generally change depending on the focal length (zoom condition) used. Further, the longer the distance from the camera body 11a to the principal point P of the imaging optical system 13, the greater the influence of bending, but this also generally changes depending on the focal length (zoom condition). Therefore, in the second embodiment, the above reference ratio is changed according to the focal length.

Here, with respect to the configurations of the camera system 11 in the second embodiment and the third embodiment described later, the same reference numerals are given to the same configurations as those in the first embodiment, and duplicate description will be omitted.

FIG. 5 is a diagram showing a control example of blur correction in the second embodiment.
Since the process shown in FIG. 5 is performed in the same manner as the process of FIG. 3 described in the first embodiment, duplicate description of the preconditions will be omitted.

In step S500a, the body CPU 12a acquires information on the imaging conditions (exposure time, focal length, etc.) of the camera system 11 referred to in the subsequent control, and lens barrel information of the interchangeable lens 11b.

The lens barrel information is, for example, information about the interchangeable lens 11b indicating the total length, rigidity, distance to the principal point P, and the like of the interchangeable lens 11b. The information regarding the interchangeable lens 11b is not controlled by directly referring to the value thereof, but is used when estimating the magnitude of the influence of the bending of the interchangeable lens 11b by the method described later. Therefore, it is sufficient that the lens barrel information is prepared as a dimensionless quantity with a small amount of data, similar to the information regarding P1 and P2 described in the first embodiment.

In step S500b, the body CPU 12a estimates the magnitude of the influence of the bending of the interchangeable lens 11b on the blur correction based on the lens barrel information and the focal length acquired in step S500a.

For example, consider the case where the interchangeable lens 11b is a zoom lens. The body CPU 12a considers that the state in which the zoom state is the wide end (focal length: short) and the total length is the shortest is the minimum effect of bending, and estimates the degree of influence of bending at this minimum as 20%. Further, the body CPU 12a considers that the state in which the zoom state is the tele end (focal length: long) and the total length is the longest is the maximum effect of bending, and estimates the degree of influence of bending at this maximum as 80%. .. Then, the body CPU 12a allocates and estimates the degree of influence of the bending in the intermediate zoom state from the time when the bending is the minimum to the time when the bending is the maximum.

Further, the body CPU 12a may estimate the magnitude of the influence of the bending of the interchangeable lens 11b in consideration of the type of the zoom lens and the rigidity of the lens barrel.
For example, the body CPU 12a estimates the influence of bending at the wide end to be 30% and the influence of bending at the tele end to be 90% for a zoom lens having a long overall length (for example, a focal length of 70-300 mm). On the other hand, the body CPU 12a estimates that the influence of bending at the wide end is 10% and the influence of bending at the tele end is 70% for a zoom lens having a short overall length (for example, a focal length of 24-70 mm).
Further, the body CPU 12a may have a low influence when the lens barrel of the interchangeable lens 11b is made of a metal having a relatively high rigidity, while having a high influence when the lens barrel is made of a resin. Good.

In step S501, the body CPU 12a determines whether the influence of the bending of the interchangeable lens 11b estimated in step S500b is large (for example, whether the estimated degree of influence is larger than a predetermined threshold value). When it is determined that the influence of bending is large, the process shifts to step S502, and when it is not determined that the influence of bending is large, the process shifts to step S503.

In step S502, the body CPU 12a controls the adjustment unit 16 to increase the ratio of referring to the signal of the first vibration detection unit 15. After that, the process proceeds to step S504.
On the other hand, in step S503, the body CPU 12a controls the adjustment unit 16 to increase the ratio of referring to the signal of the second vibration detection unit 17. After that, the process proceeds to step S504.

The processes of steps S502 and S503 are basically the same as the processes of steps S302 and S303 of FIG. 3, respectively. However, in setting the coefficient of the reference ratio in steps S502 and S503, the body CPU 12a may use the degree of influence estimated in step S500b. For example, the body CPU 12a uses the ratio of referring to the signal of the first vibration detection unit 15 as the numerical value of the degree of influence, and the ratio of referring to the signal of the second vibration detection unit 17 is the remaining portion of the degree of influence (influenced from 100%). It may be the value obtained by subtracting the numerical value of the degree.

The processes of steps S504 to S508 shown in FIG. 5 correspond to the processes of steps S304 to S308 of FIG. 3, respectively. Since these processes are the same as the corresponding processes in FIG. 3 except that the process returns to step S500a when No in step S508 (when the shooting is not completed), the description of each process will be omitted.

As described above, in the blur correction in the second embodiment, the reference ratio between the detection result of the first vibration detection unit 15 on the interchangeable lens 11b side and the detection result of the second vibration detection unit 17 on the camera body 11a side. Is changed according to the imaging conditions (focal length). As a result, it is possible to suppress a decrease in accuracy of blur correction due to a change in imaging conditions.

<Third Embodiment>
In the third embodiment, a method of referring to the signal of each vibration detection unit in the adjustment unit 16 for each frequency band will be described.
FIG. 6 is a diagram showing a configuration example of the adjusting unit 16 in the third embodiment. The adjustment unit 16 shown in FIG. 6 includes a high-pass filter (low-frequency attenuation filter) 16a, a low-pass filter (high-frequency attenuation filter) 16b, an addition unit 16c, and a correction signal creation unit 16d.

In FIG. 6, the high-pass filter 16a receives the signal of the first vibration detection unit 15, and the low-pass filter 16b receives the signal of the second vibration detection unit 17. The output of the high-pass filter 16a and the output of the low-pass filter 16b are added by the addition unit 16c. The correction signal creation unit 16d receives the signal output from the addition unit 16c. The correction signal creation unit 16d has an integrator that integrates the output of the addition unit 16c, and calculates a blur correction signal. The blur correction signal output from the correction signal creation unit 16d is output to the first drive unit 18 or the second drive unit 19.

FIG. 7A shows an example of the characteristic 71 of the high-pass filter 16a of the adjusting unit 16, where the horizontal axis represents the frequency and the vertical axis represents the output gain. Due to the characteristic 71 of FIG. 7A, the frequency component of the signal of the first vibration detection unit 15 having a breaking point frequency f0 or less shown by the broken line 73 is attenuated. As a result, the low-frequency noise superimposed on the signal of the first vibration detection unit 15 is attenuated by the high-pass filter 16a, and the high-frequency blur component due to the bending of the lens at the time of imaging can be extracted.

FIG. 7B shows an example of the characteristic 72 of the low-pass filter 16b of the adjusting unit 16, where the horizontal axis shows the frequency and the vertical axis shows the output gain. Due to the characteristic 72 of FIG. 7B, among the signals of the second vibration detection unit 17, the frequency component having the breaking point frequency f0 or more shown by the broken line 73 is attenuated. As a result, the high-frequency blur component detected by the signal of the second vibration detection unit 17 is attenuated by the low-pass filter 16b, and the low-frequency blur component can be extracted.

In the third embodiment, the body CPU 12a (or the lens CPU 12b) changes the above-mentioned folding point frequency f0 according to the exposure time and the focal length.
FIG. 8 is a schematic diagram illustrating control of changing the characteristics of the high-pass filter 16a and the low-pass filter 16b of the adjusting unit 16.

The line segment 81 in FIG. 8A shows an example of the relationship between the folding point frequency f0 and the exposure time. In FIG. 8A, the shorter the exposure time (right side of the horizontal axis in the figure), the lower the folding point frequency f0 becomes (upper side of the vertical axis in the figure). As a result, as the exposure time becomes shorter, the signal of the first vibration detection unit 15 in the wide band on the high frequency side is referred to as the signal of the vibration detection unit when calculating the blur information of the camera system 11. That is, in the combination of the signals of the first vibration detection unit 15 and the second vibration detection unit 17, the ratio of referring to the signal of the first vibration detection unit 15 becomes large.

Therefore, highly accurate blur correction is performed in consideration of the influence of the bending of the interchangeable lens 11b. Further, since the low frequency side refers to the signal of the second vibration detection unit 17 on the camera body 11a side, the degree of influence of the low frequency noise of the gyro sensor does not easily change depending on the type of the interchangeable lens 11b, so that stable blurring occurs. You will be able to make corrections.

On the other hand, the line segment 82 in FIG. 8B shows an example of the relationship between the folding point frequency f0 and the focal length. In the example of FIG. 8B, the imaging optical system 13 is a retrofocus type zoom lens as an example of the interchangeable lens 11b, and the total length of the interchangeable lens 11b changes from long to short to long as the focal length increases. I'm assuming a lens. In FIG. 8B, the folding point frequency f0 is changed to the low frequency side as the total length of the interchangeable lens 11b becomes longer according to the focal length and the influence of bending becomes larger. As a result, it is possible to perform highly accurate and stable blur correction as in the case of FIG. 8A.

The relationship between the folding point frequency f0 and the focal length (line segment 82) shown in FIG. 8B is only an example, and depends on the specifications of the interchangeable lens 11b (behavior of change in the total length of the interchangeable lens 11b due to zooming). It has different characteristics.

The present invention is not limited to the bending of the lens barrel when capturing a still image by driving the mechanical front curtain as described above, and can be effectively applied to other disturbance vibrations.
Further, in the above-described embodiment, the case where the body CPU 12a on the camera body 11a side serves as the master to control the blur correction has been described. However, the lens CPU 12b on the interchangeable lens 11b side may serve as the master, and the blur correction may be controlled based on the instruction of the lens CPU 12b.

The present invention supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by the processing to be performed. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

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 modifications can be made within the scope of the gist thereof.

11 Camera system 11a Camera body 11b Interchangeable lens 13 Imaging optical system 13a First blur correction unit 14 Image sensor 14a Second blur correction unit 15 First vibration detection unit 16 Adjustment unit 16a High-pass filter 16b Low-pass filter 16c Addition unit 16d Correction signal creation unit 17 Second vibration detection unit 18 First drive unit 19 Second drive unit 30 Shutter

Claims (12)

An image pickup device in which a lens device having an image pickup optical system and a first vibration detection unit can be attached and detached.
An image sensor that captures an image of a luminous flux that has passed through the imaging optical system,
The second vibration detector and
A blur correction signal is calculated based on at least one of a first signal output from the first vibration detection unit and a second signal output from the second vibration detection unit, and blur correction at the time of imaging is executed. The blur correction means is provided with an adjustment unit that outputs the blur correction signal.
The distance from the principal point of the imaging optical system in the optical axis direction of the imaging optical system is shorter in the first vibration detecting unit than in the second vibration detecting unit.
The adjusting unit is an image pickup apparatus characterized in that the reference ratio for referring to the first signal and the second signal when calculating the blur correction signal is changed according to an imaging condition. The imaging device according to claim 1, wherein the adjusting unit changes the reference ratio according to an exposure time. The imaging device according to claim 2, wherein the adjusting unit increases the ratio of referring to the first signal when the exposure time is short, as compared with when the exposure time is long. The imaging device according to claim 1, wherein the adjusting unit changes the reference ratio according to the focal length of the imaging optical system. The imaging device according to claim 4, wherein the adjusting unit increases the ratio of referring to the first signal when the focal length is long, as compared with when the focal length is short. The imaging device according to claim 4 or 5, wherein the adjusting unit changes the reference ratio according to the rigidity of the lens device. The adjusting part
A high-pass filter that extracts the high-frequency blur component of the first signal,
A low-pass filter that extracts the low-frequency blur component of the second signal,
Includes an adder that adds the output of the high-pass filter and the output of the low-pass filter.
The imaging device according to any one of claims 1 to 6, wherein the adjusting unit changes the breaking frequency of the high-pass filter and the low-pass filter according to the imaging conditions. The blur correction means is characterized in that it is at least one of a first blur correction unit that moves a lens in the lens device and a second blur correction unit that moves the position of the image pickup element in the image pickup device. The image pickup apparatus according to any one of claims 1 to 7. The claim is characterized in that the adjusting unit changes the output destination of the blur correction signal between the first blur correction unit and the second blur correction unit according to the focal length of the imaging optical system. Item 8. The imaging device according to item 8. When the focal length is short, the adjusting unit sets the second blur correction unit as the output destination.
The imaging device according to claim 9, wherein the adjusting unit sets the first blur correction unit as the output destination when the focal length is long. The imaging device according to any one of claims 1 to 10, further comprising a shutter that mechanically shields the image pickup element from light to control exposure. It is a control method of an image pickup device in which a lens device having an image pickup optical system and a first vibration detection unit can be attached and detached.
The image pickup device
An image sensor that captures an image of a luminous flux that has passed through the imaging optical system,
With a second vibration detector,
The distance from the principal point of the imaging optical system in the optical axis direction of the imaging optical system is shorter in the first vibration detecting unit than in the second vibration detecting unit.
A step of calculating a blur correction signal based on at least one of a first signal output from the first vibration detection unit and a second signal output from the second vibration detection unit.
A step of outputting the blur correction signal to the blur correction means for executing the blur correction at the time of imaging, and
A step of changing the reference ratio of referring to the first signal and the second signal when calculating the blur correction signal according to the imaging conditions, and
A method for controlling an imaging device, which comprises.

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