JP2012215803A - Lens barrel, camera body and camera system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lens barrel capable of executing an appropriate focus adjustment, and further to provide a camera body and a camera system.SOLUTION: A lens barrel 200 comprises: a lens mount 201 capable of mounting a camera body 100 thereto; a diaphragm 211 for adjusting an amount of light transmitted through an imaging optical system 210; a diaphragm driving section 212 that drives the diaphragm 211 and changes a diaphragm diameter of the diaphragm 211; a lens side transmitting and receiving section 217 capable of transmitting and receiving signals to/from the camera body 100; a diaphragm diameter calculating section 231 for calculating a third diaphragm diameter that is any diaphragm diameter included in a range from a first diaphragm diameter to a second diaphragm diameter when the diaphragm diameter of the diaphragm 211 is changed from the first diaphragm diameter to the second diaphragm diameter; and a lens controlling section 203 for controlling the lens side transmitting and receiving section 217 such that the lens side transmitting and receiving section 217 transmits a diaphragm signal corresponding to the third diaphragm diameter calculated by the diaphragm diameter calculating section 231.

Description

  The present invention relates to a lens barrel, a camera body, and a camera system.

  Conventionally, a phase difference detection type focus detection apparatus using a so-called pupil division optical system is known. When the light flux from the subject is vignetted by the diaphragm, the aperture diameter (diaphragm diameter) of the diaphragm is required when calculating the defocus amount. For example, Patent Document 1 describes a focus detection device that performs correlation calculation using a diaphragm diameter. According to Patent Document 1, when calculating the value of the center of gravity of the focus detection light beam limited by a specific exit pupil aperture (for example, a diaphragm), the size of the exit pupil opening (for example, the diameter of the aperture) is required. Become. The focus detection apparatus described in Patent Document 1 calculates the defocus amount from the image shift amount using the position of the center of gravity.

JP 2008-268403 A

  Since the aperture diameter changes continuously while the aperture is being driven, the focus detection calculation cannot be performed with high accuracy.

The present invention solves the above problems by the following means. For ease of understanding, reference numerals corresponding to the drawings showing an embodiment of the present invention are given and described, but the present invention is not limited to this.
The invention according to claim 1 drives the attachment part (201) to which the camera body (100) can be attached, the diaphragm (211) for adjusting the amount of light transmitted through the imaging optical system (210), and the diaphragm (211). The aperture drive unit (212) that changes the aperture diameter of the aperture (211), the transmission / reception unit (217) that can transmit and receive signals to and from the camera body (100), and the aperture diameter of the aperture (211) are the first aperture. A computing unit (231) for computing a third diaphragm diameter which is any diaphragm diameter included in the range from the first diaphragm diameter to the second diaphragm diameter when changing from the diameter to the second diaphragm diameter; The lens barrel includes a control unit (203) that controls the transmission / reception unit (217) so as to transmit an aperture signal corresponding to the third aperture diameter calculated by (231).
The invention according to claim 6 drives the mounting portion (201) to which the camera body (100) can be mounted, the diaphragm (211) for adjusting the amount of light transmitted through the imaging optical system (210), and the diaphragm (211). A diaphragm drive unit (212) that changes the aperture diameter of the aperture (211), a transmission / reception unit (217) that can transmit and receive signals to and from the camera body (100), and a transmission / reception unit (217) at predetermined intervals. A control unit (203) for controlling the transmission / reception unit (217) to transmit an aperture signal corresponding to the aperture diameter of the aperture (211) in the predetermined period to the camera body (100), and a partial period of the predetermined period In the third embodiment, when the diaphragm diameter of the diaphragm (211) changes from the first diaphragm diameter to the second diaphragm diameter, the third diaphragm having any diaphragm diameter included in the range from the first diaphragm diameter to the second diaphragm diameter. Calculation unit for calculating diameter ( 31), the control unit (203) calculates the transmission / reception unit (217) by the calculation unit (231) when the aperture diameter of the aperture (211) changes during a part of the predetermined period. The lens barrel is characterized in that the transmission / reception unit (217) is controlled to transmit an aperture signal corresponding to the third aperture diameter.
The invention according to claim 7 drives the mounting portion (201) to which the camera body (100) can be mounted, the diaphragm (211) for adjusting the amount of light transmitted through the imaging optical system (210), and the diaphragm (211). The aperture drive unit (212) that changes the aperture diameter of the aperture (211), the transmission / reception unit (217) that can transmit and receive signals to and from the camera body (100), and the aperture diameter of the aperture (211) are the first aperture. A calculator (231) for calculating a third aperture diameter, which is any aperture diameter included in a range from the first aperture diameter to the second aperture diameter, when changing from the diameter to the second aperture diameter; A transmission / reception unit (217) is configured to transmit an aperture signal that is included in the range from the aperture diameter to the second aperture diameter and that corresponds to an aperture diameter greater than or equal to the third aperture diameter calculated by the calculation unit (231). A control unit (203) for controlling A lens barrel, wherein.
An invention according to an eighth aspect is a camera body attached to the lens barrel according to any one of the first to seventh aspects, wherein the imaging element has a focus detection pixel and an imaging pixel. The body side transmitting / receiving unit (117) capable of transmitting / receiving signals to / from the lens barrel (200), the output of the focus detection pixel, and the body side transmitting / receiving unit (117) received from the lens barrel (200). And a focus detection unit (131) that performs a focus detection calculation based on the aperture signal.
An invention according to claim 9 is a camera system comprising the lens barrel according to any one of claims 1 to 7 and the camera body according to claim 8.
Note that the configuration described with reference numerals may be improved as appropriate, or at least a part thereof may be replaced with another component.

  According to the present invention, suitable focus adjustment can be performed.

It is the perspective view which showed the lens-interchangeable camera system to which this invention is applied. It is sectional drawing which showed the lens-interchangeable camera system to which this invention is applied. It is a timing chart for demonstrating a focus detection process. It is a figure which shows the calculation method of an aperture diameter.

(First embodiment)
FIG. 1 is a perspective view showing an interchangeable lens type camera system to which the present invention is applied. FIG. 1 shows only devices and apparatuses according to the present invention, and illustration and description of other devices and apparatuses are omitted. The camera system 1 includes a camera body 100 and a lens barrel 200 that can be attached to and detached from the camera body 100.

  The camera body 100 is provided with a lens mount 101 to which the lens barrel 200 can be detachably attached. The lens barrel 200 is provided with a lens mount 201 corresponding to the lens mount 101 on the body side, to which the camera body 100 can be detachably attached. When the lens barrel 200 is attached, the contact group 102 composed of a plurality of contacts provided on the lens mount 101 becomes a contact group 202 composed of a plurality of contacts provided on the lens mount 201 of the lens barrel 200. Connected. The contact group 102 and the contact group 202 are used for power supply from the camera body 100 to the lens barrel 200 and transmission / reception of signals between the camera body 100 and the lens barrel 200.

  An imaging element 104 that has focus detection pixels and imaging pixels and outputs an imaging signal is provided behind the lens mount 101 in the camera body 100. Above the camera body 100, buttons 17a and 17b as input devices are provided. The user uses these buttons 17a and 17b to instruct the camera body 100 to shoot, set shooting conditions, and the like.

  FIG. 2 is a cross-sectional view showing an interchangeable lens type camera system to which the present invention is applied. The lens barrel 200 includes an imaging optical system 210 that forms a subject image. The imaging optical system 210 has a stop 211 that adjusts the amount of light transmitted through the imaging optical system 210. The imaging optical system 210 is composed of a plurality of lenses 210a to 210e. The plurality of lenses 210a to 210e includes a focusing lens 210d for controlling the focus position of the subject image.

  Inside the lens barrel 200, a lens control unit 203 that controls each part of the lens barrel 200 is provided. The lens control unit 203 includes a microcomputer (not shown) and its peripheral circuits. The lens control unit 203 is connected to a lens side transmission / reception unit 217, an aperture driving unit 212, a ROM 215, and a RAM 216.

  The lens side transmission / reception unit 217 can transmit / receive a signal to / from the camera body 100 via the contact groups 102 and 202. In the following description, the lens control unit 203 controls the lens side transmission / reception unit 217 so that the lens side transmission / reception unit 217 transmits a signal to the camera body 100 via the contact groups 102 and 202. It may be expressed as “the control unit 203 transmits a signal to the camera body 100”. The same applies to signal reception.

  The aperture driving unit 212 includes an actuator such as a stepping motor, for example, and drives the aperture 211 to change the aperture diameter of the aperture 211. The ROM 215 is a nonvolatile storage medium and stores a predetermined control program executed by the lens control unit 203 in advance. The RAM 216 is a volatile storage medium and is used as a storage area for various data by the lens control unit 203.

  The lens control unit 203 includes an aperture diameter calculation unit 231. The aperture diameter calculation unit 231 is a functional unit that is realized in software by the lens control unit 203 executing a predetermined control program stored in the ROM 215. The specific operation contents of the aperture diameter calculator 231 will be described in detail later.

  A shutter 115 and a filter 116 are provided on the front surface of the image sensor 104. The subject light that has passed through the imaging optical system 210 enters the image sensor 104 via the shutter 115 and the filter 116. The shutter 115 controls the exposure state of the image sensor 104. The filter 116 is an optical filter that combines an optical low-pass filter and an infrared cut filter.

  Inside the camera body 100, a body control unit 103 that controls each part of the camera body 100 is provided. The body control unit 103 includes a microcomputer (not shown), a RAM, and peripheral circuits thereof. A body-side transmitting / receiving unit 117 is connected to the body control unit 103. The body side transmission / reception unit 117 is connected to the contact group 102 and can transmit / receive a signal to / from the lens barrel 200. In the following description, the body control unit 103 controls the body side transmission / reception unit 117 so that the body side transmission / reception unit 117 transmits a signal to the lens barrel 200 via the contact groups 102 and 202. "The body control unit 103 transmits a signal to the lens barrel 200". The same applies to signal reception.

  A display device 111 configured by an LCD panel or the like is disposed on the back surface of the camera body 100. In the present embodiment, the image output cycle of the image sensor 104 for displaying a so-called through image is 60 frames per second (one frame per approximately 16 milliseconds). That is, the image signal output from the image sensor 104 is input to the body control unit 103 60 times per second. The body control unit 103 causes the display device 111 to display a subject image based on the imaging signal 60 times per second. In addition to the through image, the display device 111 displays various menu screens for setting shooting conditions and the like.

  The body control unit 103 includes a focus detection unit 131. The focus detection unit 131 is a functional unit that is realized in software by the body control unit 103 executing a predetermined control program. The focus detection unit 131 performs a well-known focus detection calculation (for example, a calculation described in Patent Document 1).

(Explanation of automatic focus adjustment)
The body control unit 103 is configured to execute a well-known automatic focus adjustment process. The automatic focus adjustment process includes a focus detection process for detecting the current focus adjustment state, and a focus adjustment process for driving the focusing lens 210d according to the detection result to perform focus adjustment. In the automatic focus adjustment process, the body control unit 103 is configured to be able to selectively use two types of focus detection processes. Specifically, the body control unit 103 can selectively use a so-called imaging surface phase difference detection focus detection process and a so-called contrast detection focus detection process. The body control unit 103 uses these two types of focus detection processing properly depending on the shooting situation, the characteristics of the subject, and the like.

  The focus detection process of the imaging surface phase difference detection method by the body control unit 103 will be described. The image sensor 104 of the present embodiment has focus detection pixels (referred to as focus detection pixels). The focus detection pixels are the same as those described in Patent Document 1. The focus detection unit 131 is described in, for example, Patent Document 1 based on the output of the focus detection pixels and the aperture signal (described in detail later) transmitted from the lens barrel 200 and received by the body side transmission / reception unit 117. Perform focus detection calculation. The body control unit 103 performs focus detection processing using the result of the focus detection calculation. The focus detection calculation is the same as that described in, for example, Patent Document 1, and thus the description thereof is omitted. The body control unit 103 performs automatic focus adjustment by driving the focusing lens 210d based on the defocus amount obtained by the focus detection process.

  The contrast detection focus detection process by the body control unit 103 will be described. The body control unit 103 calculates a focus evaluation value (contrast value) by performing a known contrast detection calculation based on a so-called hill-climbing method using pixel output data from the imaging pixels included in the imaging element 104. The body control unit 103 performs this contrast detection calculation while driving the focusing lens 210d in a range described later, and performs automatic focus adjustment by detecting the position of the focusing lens 210d where the focus evaluation value reaches a peak.

(Description of focus detection processing)
The image sensor 104 accumulates charges in each pixel (light receiving element) every predetermined imaging cycle (for example, 1/30 second). The body control unit 103 receives an imaging signal output from the imaging element 104 for each imaging cycle. This imaging signal includes the output of the focus detection pixel and the output of the imaging pixel. The body control unit 103 controls the body side transmission / reception unit 117 so that a request signal for requesting an aperture signal is transmitted from the body side transmission / reception unit 117 in synchronization with the imaging cycle. That is, the lens side transmission / reception unit 217 receives the request signal in synchronization with the imaging cycle of the camera body 100.

  The lens side transmission / reception unit 217 receives a request signal for an aperture signal transmitted from the camera body 100 for each imaging cycle. When the request signal is received by the lens-side transmission / reception unit 217, the lens control unit 203 controls the lens-side transmission / reception unit 217 to transmit an aperture signal in accordance with the request signal. This aperture signal corresponds to the aperture diameter calculated by the aperture diameter calculator 231. That is, when the lens-side transmitting / receiving unit 217 receives the request signal, the aperture diameter calculating unit 231 first calculates the aperture diameter, and then the lens-side transmitting / receiving unit 217 transmits an aperture signal corresponding to the aperture diameter.

  The body control unit 103 displays a so-called through image on the display device 111 using the output of the imaging pixels included in the imaging signal. The focus detection unit 131 performs focus detection calculation based on the output of the focus detection pixels included in the imaging signal and the aperture signal transmitted from the lens barrel 200 and received by the body-side transmission / reception unit 117. In the following description, the aperture diameter of the aperture 211 is represented by the control F value of the imaging optical system 210. For example, “the aperture diameter of the aperture 211 is F5.6” will be described, indicating that the aperture diameter of the aperture 211 is a size such that the F value of the imaging optical system 210 is F5.6.

  FIG. 3 is a timing chart for explaining the focus detection process. The upper part of FIG. 3 shows the operation of each part of the camera system 1, the lower part of FIG. 3 shows the transition of the aperture diameter of the diaphragm 211, and the passage of time as the horizontal axis. In the upper part of FIG. 3, squares represent various processes.

  First, in the first period P1, charges are accumulated in the image sensor 104 (AP1). Here, in the first period P1 in which charges are accumulated, the aperture diameter of the aperture 211 is assumed to be F5.6. In the second period P2 and the third period P3 subsequent to the first period P1, charges are similarly accumulated in the image sensor 104.

  On the other hand, in the second period P2, the body control unit 103 receives an imaging signal output from the imaging element 104 (BP1). The body control unit 103 further controls the body side transmission / reception unit 117 so that a request signal for requesting the aperture signal is transmitted from the body side transmission / reception unit 117 (CP1). When the lens-side transmitting / receiving unit 217 receives the request signal in the second period P2, the aperture diameter calculator 231 calculates the aperture diameter of the aperture 211 in the first period P1. As shown in FIG. 3, since the aperture diameter of the diaphragm 211 is a size corresponding to F5.6 throughout the first period P1, the diaphragm diameter calculator 231 sets the diaphragm diameter of the diaphragm 211 in the first period P1 to F5. .6 is calculated. As described above, when the aperture diameter of the aperture 211 does not change over the entire imaging period P, the aperture diameter calculation unit 231 according to the present embodiment calculates the aperture diameter at the start of the imaging period P as the aperture diameter of the period. To do.

  Thereafter, the lens control unit 203 controls the lens-side transmission / reception unit 217 so as to transmit an aperture signal corresponding to the aperture diameter calculated by the aperture diameter calculation unit 231. By this control, an aperture signal corresponding to F5.6 is transmitted from the lens side transmission / reception unit 217 to the camera body 100, and the body side transmission / reception unit 117 receives the aperture signal (DP1).

  Thus, the body control unit 103 can handle the output of the focus detection pixel in the first period P1 and the aperture diameter of the diaphragm 211 in the first period P1 in the third period P3. In the third period P3, the focus detection unit 131 outputs the focus detection pixel output in the first period P1 and the aperture signal transmitted from the lens barrel 200 and received by the body side transmission / reception unit 117 in the second period P2. Based on this, a focus detection calculation is performed (EP1). After that, the body control unit 103 transmits a driving signal indicating a driving instruction for the focusing lens 210d to the lens barrel 200 based on the calculation result (FP1). The lens control unit 203 transmits the drive signal received by the lens side transmission / reception unit 217 to the aperture drive unit 212. The diaphragm drive unit 212 that has received the drive signal drives the diaphragm 211 by the amount represented by the drive signal. That is, the aperture driving unit 212 receives a drive signal that is not synchronized with a request signal for requesting an aperture signal, and drives the aperture 211 in accordance with the drive signal.

  As described above, charge accumulation by the image sensor 104, output of an image signal from the image sensor 104, calculation of the aperture diameter by the aperture diameter calculator 231, and aperture by the lens side transmitter / receiver 217 and the body side transmitter / receiver 117. Automatic focus adjustment of the imaging optical system 210 is realized by repeatedly performing signal transmission / reception, focus detection calculation by the focus detection unit 131, and transmission of a lens drive instruction by the body control unit 103 for each imaging period P. Is done.

  Next, calculation of the aperture diameter when the aperture 211 is driven by the aperture drive unit 212 will be described. As shown in FIG. 3, consider a case where the diaphragm 211 is driven from F5.6 to F2.8 in the third period P3. In the present embodiment, it is assumed that the time required for driving the diaphragm 211 is shorter than the imaging period P.

  In the period in which the diaphragm 211 is driven as in the third period P3, the diaphragm diameter of the diaphragm 211 continuously changes. As a result, the camera body 100 cannot grasp the aperture diameter of the aperture 211 in the third period P3.

  Since the body controller 103 issues a drive instruction for the diaphragm 211, the body controller 103 knows the diaphragm diameter before driving and the diaphragm diameter after driving. However, even if either the aperture diameter before driving (F5.6) or the aperture diameter after driving (F2.8) is used for the focus detection calculation, the error of the calculation result becomes large.

  Therefore, in the present embodiment, the aperture diameter calculator 231 calculates an aperture diameter (F4.0) that represents the third period P3 in which the aperture 211 has been driven. That is, the aperture diameter calculation unit 231 performs the first aperture diameter and the second aperture diameter when the aperture diameter of the aperture 211 changes from the first aperture diameter (for example, F5.6) to the second aperture diameter (for example, F2.8). A third aperture diameter (for example, F4.0) corresponding to the aperture diameter between and is calculated. Since the lens control unit 203 controls the lens-side transmission / reception unit 217 to transmit the aperture signal corresponding to the third aperture diameter (for example, F4.0) calculated by the aperture diameter calculation unit 231, as a result, the camera body 100 Can obtain an appropriate aperture diameter for performing the focus detection calculation in the period.

  When the diaphragm 211 is driven in a predetermined period (imaging period P), the diaphragm diameter calculation unit 231 of the present embodiment averages the diaphragm diameter of the period between the diaphragm diameter before driving and the diaphragm diameter after driving. It calculates by. For example, if the aperture diameter before driving is F5.6 and the aperture diameter after driving is F2.8, the aperture diameter calculator 231 calculates F4.0, which is the average of these aperture diameters.

According to the camera system according to the first embodiment described above, the following operational effects can be obtained.
(1) When the diaphragm diameter of the diaphragm 211 changes from the first diaphragm diameter to the second diaphragm diameter, any diaphragm diameter included in the range from the first diaphragm diameter to the second diaphragm diameter by the diaphragm diameter calculator 231 The third aperture diameter is calculated. The lens control unit 203 controls the lens side transmission / reception unit 217 so as to transmit an aperture signal corresponding to the third aperture diameter calculated by the aperture diameter calculation unit 231. Since this is done, the focus detection calculation can be performed with high accuracy even while the aperture is being driven.

(2) The lens control unit 203 receives the request signal transmitted from the camera body 100 at every predetermined cycle by the lens side transmission / reception unit 217, and transmits the aperture signal according to the request signal. To control. Since it did in this way, for example, when not using an automatic focus adjustment function, when the camera body 100 does not need to know an aperture diameter, the communication amount can be reduced.

(3) The lens control unit 203 controls the lens side transmission / reception unit 217 such that the lens side transmission / reception unit 217 receives the request signal in synchronization with the imaging cycle of the camera body 100. Since this is done, various processes are executed at a constant pace in cooperation with a process such as outputting a through image, and the processing amounts of the body control unit 103 and the lens control unit 203 can be easily estimated.

(4) The diaphragm drive unit 212 receives a drive signal that is not synchronized with the request signal, and drives the diaphragm 211 in accordance with the drive signal. Since it did in this way, it becomes possible to drive the aperture 211 at any time regardless of the imaging period P, and the response of the aperture drive is improved.

  The following modifications are also within the scope of the present invention, and one or a plurality of modifications can be combined with the above-described embodiment.

(Modification 1)
In the first embodiment, when the diaphragm 211 is driven, the diaphragm diameter calculator 231 calculates the diaphragm diameter by averaging the diaphragm diameter before driving and the diaphragm diameter after driving. The method of calculating the aperture diameter in the present invention is not limited to this.

  FIG. 4 is a diagram illustrating a method for calculating the aperture diameter. FIG. 4A shows a calculation method of the aperture diameter calculation unit 231 in the first embodiment. That is, in FIG. 4A, the aperture diameter calculator 231 averages the aperture diameter (F5.6) at the start time T1 of the imaging cycle P and the aperture diameter (F2.8) at the end time T2 of the imaging cycle P. By doing so, the aperture diameter (F4) of the imaging period P is calculated.

  The present invention is not limited to the aperture diameter calculation method shown in FIG. 4A, and the calculation method shown in FIG. 4B or the calculation method shown in FIG. 4C can also be used. In the calculation method shown in FIG. 4B, the aperture diameter (F2.8) of the aperture 211 at an exactly intermediate time T3 of the imaging period P for which the aperture signal is requested by the request signal is used as the aperture diameter of the imaging cycle P. It is to calculate. That is, in FIG. 4B, the aperture diameter calculator 231 calculates the aperture diameter of the aperture 211 at a predetermined time (intermediate time) based on the request signal as the third aperture diameter.

  In the calculation method shown in FIG. 4C, first, a period Pa from the start time T1 of the imaging period P to time T4 when the driving of the diaphragm 211 is started, and from time T4 to time T5 when the driving of the diaphragm 211 is completed. The period Pb and the period Pc from the time T5 to the end time T2 of the imaging period P are calculated. Thereafter, the aperture diameter before driving (F5.6), the aperture diameter after driving (F2.8), and the average aperture diameter (F4) correspond to the length of the period Pa, the period Pc, and the period Pb, respectively. The aperture diameter of the imaging period P is calculated by calculating a weighted average multiplied by the weight. By doing so, it is possible to perform a focus detection calculation with higher accuracy.

  Of course, the aperture diameter calculation method by the aperture diameter calculation unit 231 is not limited to the calculation methods shown in FIGS. 4A to 4C, and may be another calculation method. As shown in FIG. 4B, the calculated aperture diameter may be equal to the aperture diameter before driving or the aperture diameter after driving.

(Modification 2)
The lens control unit 203 is not the third aperture diameter itself calculated by the aperture diameter calculating unit 231, but is included in the range from the first aperture diameter to the second aperture diameter and larger than the third aperture diameter. The lens-side transmitting / receiving unit 217 may be controlled to transmit an aperture signal corresponding to. In other words, a diaphragm signal corresponding to a diaphragm diameter that is larger than the calculated third diaphragm diameter and does not exceed the first diaphragm diameter or the second diaphragm diameter may be transmitted. In this way, although the defocus amount obtained by the focus detection process of the body control unit 103 is smaller than when the aperture signal corresponding to the third aperture diameter is transmitted, the sign of the defocus amount does not change. . Therefore, the time required for focusing may be longer than when the aperture signal corresponding to the third aperture diameter is transmitted, but focusing itself can be performed correctly.

  As long as the characteristics of the present invention are not impaired, the present invention is not limited to the above-described embodiments, and other forms conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. .

DESCRIPTION OF SYMBOLS 1 ... Camera system, 100 ... Camera body, 101, 201 ... Lens mount, 103 ... Body control part, 104 ... Image sensor, 117 ... Body side transmission / reception part, 131 ... Focus detection part, 200 ... Lens barrel, 203 ... Lens Control unit 210... Imaging optical system 210 d Focusing lens 211. Diaphragm 212. Diaphragm drive unit 215... ROM 216.

Claims (9)

An attachment part to which the camera body can be attached;
A diaphragm for adjusting the amount of light transmitted through the imaging optical system;
An aperture drive unit that drives the aperture and changes the aperture diameter of the aperture; and
A transmission / reception unit capable of transmitting / receiving a signal to / from the camera body;
When the diaphragm diameter of the diaphragm changes from the first diaphragm diameter to the second diaphragm diameter, a third diaphragm diameter that is any diaphragm diameter included in the range from the first diaphragm diameter to the second diaphragm diameter is set. A computing unit for computing,
A lens barrel comprising: a control unit that controls the transmission / reception unit so as to transmit an aperture signal corresponding to the third aperture diameter calculated by the calculation unit. The lens barrel according to claim 1,
The control unit controls the transmission / reception unit so that the transmission / reception unit receives a request signal transmitted from the camera body at predetermined intervals, and transmits the aperture signal according to the request signal. Lens barrel to be used. The lens barrel according to claim 2,
The control unit controls the transmission / reception unit such that the transmission / reception unit receives the request signal in synchronization with an imaging cycle of the camera body. In the lens barrel according to claim 2 or 3,
The lens barrel, wherein the aperture driving unit receives a drive signal that is not synchronized with the request signal, and drives the aperture according to the drive signal. The lens barrel according to claim 2,
The lens unit according to claim 1, wherein the calculation unit calculates a diaphragm diameter of the diaphragm at a predetermined time based on the request signal as the third diaphragm diameter. An attachment part to which the camera body can be attached;
A diaphragm for adjusting the amount of light transmitted through the imaging optical system;
An aperture drive unit that drives the aperture and changes the aperture diameter of the aperture; and
A transmission / reception unit capable of transmitting / receiving a signal to / from the camera body;
A control unit that controls the transmission / reception unit so that the transmission / reception unit transmits an aperture signal corresponding to the aperture diameter of the aperture in the predetermined period to each camera unit, and a partial period of the predetermined period In this case, when the diaphragm diameter of the diaphragm changes from the first diaphragm diameter to the second diaphragm diameter, the third diaphragm having any diaphragm diameter included in the range from the first diaphragm diameter to the second diaphragm diameter. A calculation unit for calculating the diameter,
When the diaphragm diameter of the diaphragm changes during a partial period of the predetermined period, the control unit outputs the diaphragm signal corresponding to the third diaphragm diameter computed by the computing unit. A lens barrel that controls the transmission / reception unit to transmit data. An attachment part to which the camera body can be attached;
A diaphragm for adjusting the amount of light transmitted through the imaging optical system;
An aperture drive unit that drives the aperture and changes the aperture diameter of the aperture; and
A transmission / reception unit capable of transmitting / receiving a signal to / from the camera body;
When the diaphragm diameter of the diaphragm changes from the first diaphragm diameter to the second diaphragm diameter, a third diaphragm diameter that is any diaphragm diameter included in the range from the first diaphragm diameter to the second diaphragm diameter is set. A computing unit for computing,
The transmission / reception is performed so as to transmit an aperture signal included in a range from the first aperture diameter to the second aperture diameter and corresponding to an aperture diameter greater than or equal to the third aperture diameter calculated by the calculation unit. And a control unit that controls the lens unit. A camera body attached to the lens barrel according to any one of claims 1 to 7,
An imaging device having focus detection pixels and imaging pixels;
A body side transmitting / receiving unit capable of transmitting and receiving signals to and from the lens barrel;
A camera body comprising: a focus detection unit that performs a focus detection calculation based on an output of the focus detection pixel and the aperture signal transmitted from the lens barrel and received by the body-side transmission / reception unit .   A camera system comprising: the lens barrel according to claim 1; and the camera body according to claim 8.

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