JP2010107710A - Camera body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera body capable of more efficiently estimating and calculating information about the brightness of an interchangeable lens while accommodating various interchangeable lenses. <P>SOLUTION: The camera body has a CPU. The CPU acquires an open aperture value table from the interchangeable lens, sequentially acquires a zoom position from the interchangeable lens, transmits an aperture value to the interchangeable lens to adjust a diaphragm, acquires differential information about the dimension of a difference, based on the transmitted aperture value when the aperture value is transmitted, between the transmitted aperture value and an aperture value found in compliance with the open aperture value table and the zoom position obtained immediately before, and after acquiring the differential information, estimates a current aperture value of the interchangeable lens by using the differential information, the zoom position and the acquired open aperture value table when acquiring the zoom position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a camera body to which an interchangeable lens can be attached and detached.

  Conventional camera bodies include those described in Patent Document 1.

  Patent Document 1 provides a photometric device for an interchangeable lens camera that can always perform appropriate exposure control even if the amount of extension of the interchangeable lens changes. Specifically, in Patent Document 1, “in an interchangeable lens camera equipped with photometry means, effective open aperture value calculating means for calculating an effective open aperture value that changes in accordance with the lens extension amount of the interchangeable lens; There has been proposed a “photometric device for an interchangeable lens camera” comprising an exposure calculation means for performing an exposure calculation using a value.

Here, the camera body described in Patent Document 1 acquires the aperture value and the focal length from the interchangeable lens in order to calculate the effective open aperture value. Thus, the camera body applies the acquired aperture value and focal length to the mathematical formula, and calculates the effective open aperture value of the interchangeable lens (hereinafter referred to as the effective aperture value of the interchangeable lens).
Japanese Patent Laid-Open No. 1-100525

  Here, in Patent Document 1, an effective aperture value corresponding to the focal length is obtained using a mathematical expression that is considered to be stored in advance in the camera body. However, the interchangeable lens can vary the change in the effective aperture value with the lens extension amount according to the designer's design concept. In other words, an interchangeable lens can be configured such that the effective aperture value is not changed even when the lens is extended. On the other hand, other interchangeable lenses can be configured to change the effective aperture value when the lens is extended. For this reason, since the camera body of Patent Document 1 responds with a mathematical formula stored in advance, there is a possibility that the effective aperture value cannot be calculated for all the interchangeable lenses. For this reason, the camera body may not be able to perform appropriate control regarding exposure control.

  Note that the zoom magnification of an interchangeable lens having a zoom ring may be changed by a user's manual operation. In such a case, the effective aperture value of the interchangeable lens may change according to the zoom magnification. Therefore, when the camera body cannot know the changed effective aperture value from the interchangeable lens when capturing a moving image, the brightness of the captured image cannot be kept constant. That is, when the camera body cannot know the effective aperture value, the brightness of the captured image changes because the exposure control cannot be put on the correct program diagram.

  This will be specifically described with reference to FIG. The interchangeable lens is configured to change the aperture value when the zoom magnification is changed. First, as shown in FIG. 15, it is assumed that the camera body transmits a control signal for causing the interchangeable lens to adjust the aperture. At this time, the interchangeable lens adjusts the aperture according to the aperture value (F8) based on the received signal. Thereafter, it is assumed that the zoom ring of the interchangeable lens is operated by the user. Thus, when the user operates the zoom ring, the zoom magnification of the interchangeable lens is changed. When the zoom magnification of the interchangeable lens is changed, the aperture value of the interchangeable lens is also changed. For example, with an interchangeable lens, the aperture value is from F8 to F11. Here, unless the configuration is such that the aperture value is transmitted from the interchangeable lens to the camera body, the camera body cannot detect that the aperture value has been changed. That is, the camera body determines that the aperture value of the interchangeable lens is F8, and adjusts the ISO sensitivity and exposure time of the image sensor. For this reason, the camera body cannot perform appropriate exposure control.

  The camera body may control contrast AF based on the aperture value of the interchangeable lens. For example, when the aperture value of the interchangeable lens is large, the camera body sets a focus position search range (a range in which the focus lens is operated to search for the focus position) and performs contrast AF. On the other hand, when the aperture value of the interchangeable lens is small, the camera body sets the focus position search range to be narrow and performs contrast AF. Thus, the camera body can shorten the search time when searching for the in-focus position in contrast AF. However, if the camera body cannot grasp the effective aperture value of the interchangeable lens, the camera body sets the focus position search range based on the wrong aperture value. In this case, when the effective aperture value of the interchangeable lens is changed to F11 and the depth of field becomes deeper, the camera body sets the search range based on the aperture value F8, and thus a highly accurate focus position. May lead to the inability to discover.

  Here, the contrast AF is generally used to find an optimum in-focus position using blur of image data. Therefore, when the zoom magnification of the interchangeable lens is changed and the depth of field becomes deep, the in-focus position search range is included in the depth of field. For this reason, even if the focus lens is driven and the in-focus position is searched, a blurred image cannot be obtained, and high-precision in-focus adjustment cannot be performed.

  Therefore, in order to solve the above-described problem, the present invention is more efficient for an interchangeable lens while supporting various interchangeable lenses even when an effective aperture value (information on brightness) cannot be directly obtained from the interchangeable lens. An object of the present invention is to provide a camera body that can estimate and calculate information on the brightness of the camera.

  That is, the present invention provides a camera body that can be attached to and detached from an interchangeable lens having a diaphragm and a movable lens, and the information on the lens position of the movable lens when the diaphragm is adjusted to a specific aperture diameter. Corresponding information acquisition means for acquiring information related to the brightness of the interchangeable lens from the interchangeable lens, and lens position acquisition for sequentially acquiring information regarding the lens position of the movable lens from the interchangeable lens. And means for transmitting information relating to brightness to the interchangeable lens in order to adjust the aperture, and when information relating to brightness is transmitted by the transmitting means, based on the transmitted information relating to brightness The brightness required in accordance with the acquired relation information and the information on the lens position acquired immediately before Difference acquisition means for acquiring difference information regarding the magnitude of the difference between the information, and after acquiring the difference information by the difference acquisition means, if the information on the lens position is acquired by the lens position acquisition means, the difference information, And estimation means for estimating information on the current brightness of the interchangeable lens using the information on the lens position and the acquired relationship information.

  If it does in this way, the camera main body can acquire the information regarding the brightness of an interchangeable lens based on the acquired information and difference information from the interchangeable lens by acquiring the relationship information and the information regarding the lens position.

  Preferably, the movable lens is a zoom lens.

  Preferably, the apparatus further includes a reception unit that receives an operation from a user, and the transmission unit transmits information on brightness to adjust the diaphragm according to the received operation from the user. Send to.

  The camera body of the present invention acquires relation information and information regarding the lens position from the interchangeable lens, and estimates information regarding the brightness of the interchangeable lens based on the acquired information and difference information. This allows the camera body to estimate brightness information more efficiently on the camera body side, while supporting various interchangeable lenses, even when information about brightness cannot be obtained directly from the interchangeable lens. It becomes possible to do.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. An example in which the present invention is applied to a digital camera will be described.
(Embodiment 1)
The digital camera 1 according to the first embodiment includes a camera body 2 and an interchangeable lens 3.

  The camera body 2 acquires, from the interchangeable lens 3, relationship information that can determine the AV value of the interchangeable lens 3 in accordance with the zoom position of the zoom lens 303, assuming that the aperture 307 is adjusted to the open state. . The camera body 2 stores this relationship information in the buffer memory 204. At this time, it is assumed that the interchangeable lens 3 is adjusted to an open state.

  In addition, the camera body 2 sequentially acquires the zoom position of the zoom lens 303 from the interchangeable lens 3. The camera body 2 calculates the effective AV value of the interchangeable lens 3 according to the acquired zoom position and the relationship information stored in the buffer memory 204. Therefore, the camera body 2 can calculate the effective AV value of the interchangeable lens even when the zoom position changes when the aperture 307 is adjusted to the open state. In the present embodiment, in order to simplify the overall design of the camera body, the effective AV value is calculated by adding the difference information “0”. The difference information is stored in the buffer memory 204.

  Here, the camera body 2 accepts a change in the aperture value of the interchangeable lens 3 by operating the dial 220 from the user (in this embodiment, the aperture value is accepted in terms of AV value). When the camera body 2 receives the change of the aperture value, the camera body 2 transmits control information for adjusting the aperture 307 to the zoom lens 303. Accordingly, the interchangeable lens 3 adjusts the amount of light passing through the interchangeable lens 3 by adjusting the aperture diameter of the diaphragm 307. At this time, the camera body 2 stores the difference between the AV value calculated according to the zoom position acquired immediately before and the accepted AV value in the buffer memory 204 as difference information. That is, the camera body 2 can predict how much the aperture state of the diaphragm 307 has been adjusted by acquiring the magnitude of the difference between the AV value that can be calculated according to the relationship information and the received AV value. .

  Thereafter, when the zoom position is transmitted from the interchangeable lens 3, the camera body 2 acquires an effective AV value corresponding to the zoom position. Specifically, the camera body 2 calculates an effective AV value using the zoom position, the relationship information, and the difference information.

  Accordingly, the camera body 2 can calculate the effective AV value by using the difference information even when the aperture 307 is adjusted to an open state other than the open state. For this reason, since the camera body 2 can estimate and calculate the effective AV value in the body itself, the camera body 2 can be put on a correct program diagram during exposure control. This allows the camera body to perform appropriate exposure control.

[1. Constitution〕
[1-1 Overview of overall configuration]
FIG. 1 is a perspective view of a digital camera 1 according to the present embodiment. FIG. 2 is a configuration diagram of the digital camera 1 according to the present embodiment.

  The digital camera 1 according to the present embodiment includes a camera body 2 and an interchangeable lens 3 that can be attached to and detached from the camera body 2.

  The camera body 2 includes a CMOS sensor 201, a mechanical shutter 202, a signal processor 203 (DSP), a buffer memory 204, a liquid crystal monitor 205, an electronic viewfinder 206 (EVF), a power supply 207, a body mount 208, a flash memory 209, and a card slot 210. , CPU 211, shutter switch 212, flash 213, microphone 214, speaker 215, and dial 220.

  The interchangeable lens 3 includes a lens mount 301, a zoom lens 303, a focus lens 304, a lens system including an OIS lens 305, a focus drive unit 306 that drives the focus lens 304, an OIS drive unit 320 that drives the OIS lens 305, and an aperture 307. A diaphragm drive unit 308 that drives the diaphragm 307, a zoom ring 309, a focus ring 310, a lens controller 311, a buffer memory 312, a zoom lens position detector 313, a flash memory 314, and a gyro sensor 330.

[1-2 Configuration of the camera body 2]
The camera body 2 is configured to capture a subject image condensed by the lens system of the interchangeable lens 3 and record the captured image data in a storage medium (memory card or the like).

  The CMOS sensor 201 includes a light receiving element, an AGC (gain control amplifier), and an AD converter. The light receiving element converts the optical signal collected by the lens system into an electrical signal, and generates image data. The AGC amplifies the electric signal output from the light receiving element. The AD converter converts an electric signal output from the AGC into a digital signal. Note that the CMOS sensor 201 performs various operations such as exposure, transfer, and electronic shutter in accordance with control signals received from the CPU 211. These various operations can be realized by a timing generator or the like.

  The mechanical shutter 202 switches between blocking and passing an optical signal incident on the CMOS sensor 201 that is incident through the lens system. The mechanical shutter 202 is driven by a mechanical shutter driving unit. The mechanical shutter drive unit includes mechanical parts such as a motor and a spring, and drives the mechanical shutter 202 under the control of the CPU 211. In short, the mechanical shutter 202 is opened and closed to adjust the amount of light hitting the CMOS sensor 201 in terms of time.

  The signal processor 203 (DSP) performs predetermined image processing on the image data converted into a digital signal by the AD converter. Examples of the predetermined image processing include gamma conversion, YC conversion, electronic zoom processing, compression processing, and expansion processing, but are not limited thereto.

  The buffer memory 204 functions as a work memory when the signal processor 203 performs processing and when the CPU 211 performs control processing. The buffer memory 204 can be realized by, for example, a DRAM.

  The liquid crystal monitor 205 is disposed on the back surface of the camera body 2 and can display image data generated by the CMOS sensor 201 or image data obtained by performing predetermined processing on the image data. Here, when the image signal input to the liquid crystal monitor 205 is output from the signal processor 203 to the liquid crystal monitor 205, it is converted from a digital signal to an analog signal by the DA converter.

  The electronic viewfinder 206 is disposed in the camera body 2 and can display image data generated by the CMOS sensor 201 or image data obtained by performing predetermined processing on the image data. Similarly, when an image signal input to the electronic viewfinder 206 is output from the signal processor 203 to the electronic viewfinder 206, the digital signal is converted from an analog signal by a DA converter.

  Here, the display on the liquid crystal monitor 205 and the electronic viewfinder 206 is displayed on one side by the display switching means 217. That is, nothing is displayed on the electronic viewfinder 206 while an image is displayed on the liquid crystal monitor 205. Further, while the image is displayed on the electronic viewfinder 206, nothing is displayed on the liquid crystal monitor 205. The display switching unit 217 can be realized by a physical structure such as a changeover switch, for example. For example, when the signal processor 203 and the liquid crystal monitor 205 are electrically connected, the electrical connection between the signal processor 203 and the liquid crystal monitor 205 is disconnected by switching the changeover switch, and the signal processor 203 And the electronic viewfinder 206 are electrically connected. The display switching unit 217 may switch the display to the liquid crystal monitor 205 and the electronic viewfinder 206 based on a control signal from the CPU 211 or the like.

  As described above, the display on the liquid crystal monitor and the display on the electric viewfinder are switched. However, since this is a problem due to structural limitations, the display on the liquid crystal monitor and the display on the electronic viewfinder may be performed simultaneously. Here, when displaying simultaneously, the image displayed on the liquid crystal monitor and the image displayed on the electronic view funder may be the same image or different images.

  The power source 207 supplies power to be consumed by the digital camera 1. The power source 207 may be, for example, a dry battery or a rechargeable battery. Moreover, the power supplied from the outside by the power source 207 cord may be supplied to the digital camera 1.

  The body mount 208 is a member that enables the interchangeable lens 3 to be attached and detached together with the lens mount 301 of the interchangeable lens 3. The body mount 208 can be electrically connected to the interchangeable lens 3 using a connection terminal or the like, and can also be mechanically connected by a mechanical member such as a locking member. The body mount 208 can output a signal from the lens controller 311 included in the interchangeable lens 3 to the CPU 211 and can output a signal from the CPU 211 to the lens controller 311 of the interchangeable lens 3. That is, the CPU 211 can transmit and receive control signals, information on the lens system, and the like with the lens controller 311 on the interchangeable lens 3 side. In addition, the body mount 208 supplies the power supplied from the power source 207 to the lens controller 311. Thereby, the body mount 208 supplies power consumed in the interchangeable lens 3.

  The flash memory 209 is a storage medium used as a built-in memory. The flash memory 209 can store image data or image data obtained by performing predetermined processing on the image data. Also, digitized audio signals can be stored. In addition, it is possible to store programs and set values for controlling the CPU 211 in addition to image data and audio signals.

  The card slot 210 is a slot for attaching / detaching the memory card 218. The memory card 218 can store image data or image data obtained by performing predetermined processing on the image data. Also, digitized audio signals can be stored. In short, the memory card 218 is a storage medium.

  The CPU 211 controls the entire camera body 2. The CPU 211 may be realized by a microcomputer or a hard wired circuit. That is, the CPU 211 performs various controls. For various controls, see 2. It describes in.

  The shutter switch 212 is a button provided on the upper surface of the camera body 2 and detects half-pressing and full-pressing operations from the user. When the shutter switch 212 receives a half-press operation from the user, the shutter switch 212 outputs a half-press signal to the CPU 211. On the other hand, the shutter switch 212 outputs a full-press signal to the CPU 211 when a full-press operation is received from the user. Based on these signals, the CPU 211 performs various controls. In the present embodiment, the full press signal is a shooting start signal.

  The strobe 213 irradiates the subject with light based on a control signal from the CPU 211. For example, the strobe 213 can be realized using a xenon lamp, a condenser, or the like. When configured in this manner, the strobe 213 accumulates high-voltage charges in a capacitor and applies the charges to the xenon lamp electrode to irradiate light.

  The microphone 214 converts sound into an electrical signal. The electrical signal output from the microphone 214 is converted into a digital signal by an AD converter. The digital signal converted by the AD converter is stored in the flash memory 209 or the memory card 218 under the control of the CPU 211.

  The speaker 215 converts an electrical signal into sound. Here, the electrical signal input to the speaker 215 is a signal converted from a digital signal to an electrical signal by a DA converter. As the output to the DA converter, a digital signal read from the flash memory 209 or the memory card 218 is output under the control of the CPU 211.

  The dial 220 is provided on the exterior of the camera body 2. When operated by the user, the dial 220 transmits an operation signal to the CPU 211. This operation signal includes a signal indicating that the camera body 2 is rotated leftward and a signal indicating that the camera body 2 is rotated rightward. The CPU 211 is configured to accept a change in aperture value in response to the operation signal. For example, when the dial 220 is rotated to the right by the user, the CPU 211 changes the aperture value to the small aperture side. On the other hand, when the dial 220 is rotated to the left by the user, the CPU 211 changes the aperture value to the open side. As a result, the camera body accepts a change in aperture value.

  In this embodiment, the aperture value that can be set by the user is an aperture value in 1 / 3-step increments. Accordingly, the aperture value that can be set by the user is “2.8, 3.3, 3.5, 4, 4.5,..., 5.6”. In other embodiments, one step, half step, etc. can be used.

  Here, the CPU 211 having received the change of the aperture value by operating the dial 220 transmits the AV value corresponding to the aperture value after the change to the interchangeable lens 3. Thereby, the CPU 211 can control the diaphragm 307 of the interchangeable lens 3.

  The mode switching dial 221 is an operation member attached to the exterior of the camera body 2. The mode switching dial 221 is formed in a substantially circular shape, and allows the user to select one control mode from a plurality of control modes when the user rotates. That is, the mode switching dial 211 can detect a control mode moved to a predetermined position so that one control mode can be selected from among a plurality of control modes. The plurality of control modes include “still image shooting mode”, “moving image shooting mode”, “playback mode”, and the like. For example, when an image indicating “still image shooting mode” described on the upper surface of the mode switching dial is moved to a predetermined position (selected position), the mode switching dial 221 is changed to “still image shooting mode”. A mode switching signal indicating this is output to the CPU 211. As a result, the switching of the control mode can be detected.

[1-3 Configuration of Interchangeable Lens 3]
The lens system includes a zoom lens 303, a focus lens 304, an OIS lens 305, and an objective lens 302, and collects light from the subject. The zoom lens 303 is driven by the zoom ring 309 and adjusts the zoom magnification. The focus lens 304 is driven by the focus driving unit 306 or the focus ring 310 to adjust the focus. The OIS lens 305 is driven by the OIS driving unit 320. In short, the focus lens 304, the zoom lens 303, and the OIS lens 305 are movable lenses.

  Here, the OIS lens 305 is movable in a plane perpendicular to the optical axis of the optical system. By moving the OIS lens 305 in a plane perpendicular to the optical axis of the optical system, the optical axis of the optical system can be bent. By moving the OIS lens 305 in a direction that cancels the blur of the digital camera 1 detected by the OIS drive unit 320 described later, image blur due to the blur of the digital camera 1 can be prevented.

  The focus driving unit 306 drives the focus lens 304 according to the control of the lens controller 311. The focus driving unit 306 is described as an example realized by a stepping motor and a driver. The focus driving unit 306 is configured to drive the focus lens 304 when power is supplied from the lens controller 311.

  The OIS driving unit 320 drives the OIS lens 305 according to the control of the lens controller 311 based on the output of the gyro sensor 330. That is, the optical image blur correction function can be realized by the gyro sensor 330, the lens controller 311, the OIS driving unit 320, and the OIS lens 305. The gyro sensor 330 detects the movement angular velocity of the digital camera 1. The lens controller 311 calculates the angular velocity of the digital camera 1 by integrating the angular velocity detected by the OIS driving unit 320. This is the amount of blurring of the digital camera 1. Then, the lens controller 311 instructs the OIS drive unit 320 to cancel the movement of the digital camera 1 and drive the OIS lens 305 so that the subject image does not move on the CMOS sensor 201 as much as possible. The OIS driving unit 320 drives the OIS lens 305 in accordance with this instruction. As described above, the OIS lens 305 can bend the optical axis of the optical system by moving in the plane perpendicular to the optical axis of the optical system. Thereby, it is possible to prevent the subject image from moving on the CMOS sensor 201 as much as possible.

  The stop 307 adjusts the amount of light passing through the lens system. For example, the light can be adjusted by increasing or decreasing the opening formed by five blades or the like.

  The diaphragm drive unit 308 changes the size of the opening of the diaphragm 307. In the first embodiment, the size of the opening of the diaphragm 307 is changed based on the control of the lens controller 311. Here, the size of the opening can be designated by the AV value. The diaphragm driving unit 308 drives the diaphragm 307 based on the control from the lens controller 311. However, the diaphragm driving unit 308 is not limited to this and may be driven by a mechanical method.

The diaphragm driving unit 308 includes an encoder that detects the size (position) of the aperture of the diaphragm and outputs it as an AV (Aperture Value) value. The aperture driving unit 308 outputs the aperture state to the lens controller 311. The aperture state output from the aperture drive unit 308 is, for example, a value corresponding to the aperture position corresponding to the open side “1” to the small aperture side “6”. The zoom ring 309 is provided on the exterior of the interchangeable lens 3. It is provided and drives the zoom lens 303 in accordance with an operation from the user. The zoom ring 309 mechanically drives the zoom lens 303 when rotated by the user.

  The focus ring 310 is provided on the exterior of the interchangeable lens 3 and drives the focus lens 304 in accordance with an operation from the user. When the focus ring 310 is rotated by the user, the sliding resistance detects the operation, and a signal related to the operation is input to the lens controller 311. The lens controller 311 controls the focus driving unit 306 in accordance with the input operation related signal. As a result, the focus driving unit 306 drives the focus lens 304.

  The lens controller 311 controls the entire interchangeable lens 3. The lens controller 311 may be realized by a microcomputer or a hard wired circuit. That is, the lens controller 311 executes various controls. Various controls of the lens controller 311 are as follows. It describes in.

  The buffer memory 312 functions as a work memory when the lens controller 311 performs control processing. The buffer memory 312 can be realized by, for example, a DRAM.

  The flash memory 314 is configured to be electrically connected to the lens controller 311. The flash memory 314 can store control programs, parameters, and the like. The flash memory 314 stores an AV value table. As shown in FIG. 3, the AV value table shows the AV value of the aperture and the effective AV value obtained by the zoom position. The AV value can be converted into an aperture value by a general calculation formula.

  The zoom lens position detector 313 acquires information regarding the zoom position of the zoom lens 303. Specifically, the zoom position indicates the position of the zoom lens 303 that is designated in units of divided areas by dividing the movable range of the zoom lens 303 into a plurality of areas. The lens controller 311 is configured to periodically acquire information regarding the zoom position detected by the zoom lens position detector 313.

  Here, the zoom lens position detector 313 is configured by a sliding resistance or the like, and detects information related to the zoom position of the zoom lens 303 with a voltage value. In addition, the lens controller 311 periodically reads out the voltage value detected by the zoom lens position detector 313, and AD-converts this voltage value to acquire information (digital data) regarding the 256 zoom positions. . In the present embodiment, information relating to the zoom position divided into nine parts is used in order to simplify the description.

[2. Various controls in camera body 2 and interchangeable lens 3]
[2-1. Various controls of the lens controller 311]
Various controls of the lens controller 311 will be described.

  When the lens controller 311 detects that the lens mount 301 is attached to the body mount 208, the lens controller 311 transmits the open AV value table and the zoom position to the CPU 211. The wide open AV value table is information that allows the effective AV value to be obtained according to the zoom position of the zoom lens when it is assumed that the stop has been adjusted to the full open state (stop state “1”). The open AV value table uses information as shown in FIG. In the present embodiment, an open AV value table is used when it is assumed that the aperture is adjusted to the open state. This is because the aperture 307 is adjusted to the open state when the lens is mounted. That is, the lens controller 311 adjusts the aperture state to “1” (open state) when the interchangeable lens 3 is attached to the camera body 2. It should be noted that no adjustment is performed when the aperture has already been adjusted to the open state (aperture state “1”).

  In addition, the lens controller 311 transmits the zoom position of the zoom lens 303 acquired from the zoom lens position detector 313 based on the request signal from the CPU 211. The CPU 211 transmits a request signal to the lens controller 311 every time the CMOS sensor 201 generates image data. For example, the CPU 211 is enabled by detecting the timing at which exposure is started by the CMOS sensor 201. That is, when exposure is started by the CMOS sensor 201, the timing generator transmits an exposure start signal to the CPU 211. Then, the CPU 211 transmits a request signal to the lens controller 311 based on this exposure start signal. As a result, the CPU 211 can request the zoom position from the interchangeable lens 3 every time the CMOS sensor 201 generates image data.

  Furthermore, when the lens controller 311 receives a control signal for adjusting the diaphragm 307 from the CPU 211, the lens controller 311 adjusts the aperture state of the diaphragm 307 based on the control signal. For example, it is assumed that the lens controller 311 receives an AV value “4” as a control signal for adjusting the diaphragm 307. At this time, the zoom position of the zoom lens 303 is acquired from the zoom lens position detector 313. For example, assume that the zoom position is “6”. In this case, since the AV value table as shown in FIG. 3 is stored in the flash memory 314, the lens controller 311 adjusts the aperture so that the effective AV value becomes “4.1” according to the zoom position. To do. That is, the lens controller 311 adjusts the diaphragm 307 so that the state (corresponding to the aperture diameter) of the diaphragm 307 becomes “3” in order to adjust the effective AV value of the interchangeable lens to “4.1”. Thus, the lens controller 311 can adjust the aperture state of the diaphragm 307 based on the control signal.

  When the lens controller 311 receives the AV value “4” from the CPU 211, the lens controller 311 adjusts the aperture 307 so that the AV value of the interchangeable lens becomes the effective AV value “4.1”. This is because, in this embodiment, the aperture value that can be set by the user is set in increments of 1/3 according to the JIS standard. That is, the aperture value that can be set by the user may differ from the effective aperture value that can actually be set for the interchangeable lens. Therefore, in the present embodiment, when an AV value different from the effective aperture value is received from the CPU, the aperture is adjusted so that the effective AV value is closest to the received AV value. For example, in the case of the zoom position “1”, when the lens controller 311 receives an AV value “3” from the CPU 211, the lens controller 311 reduces the aperture so that the nearest effective AV value “3.1” in the AV value table is obtained. adjust. Further, in the case of the zoom position “8”, when the lens controller 311 receives the AV value “5” from the CPU 211, the lens controller 311 adjusts the aperture so that the effective AV value “5” closest in the AV value table is obtained. . Therefore, when the zoom position is “6” and the lens controller 311 receives a control signal (AV value “4”) from the CPU 211, the lens controller 311 has the highest AV value “4.0” in the AV value table. The aperture is adjusted so that the effective AV value is close to “4.1”.

[2-2. Various controls of CPU 211]
Various controls of the CPU 211 will be described.

  The CPU 211 acquires the open AV value table and the zoom position from the lens controller 311. When the CPU 211 receives the open AV value table and the zoom position, the CPU 211 stores the open AV value table in the buffer memory 204. The CPU 211 calculates and stores the current effective AV value using the open AV value table and the zoom position. For example, in the open AV value table as shown in FIG. 4, when the zoom position is “6”, the CPU 211 calculates that the current effective AV value is “3.4”. At this time, the CPU 211 sets “0” in the difference information because there is no difference between the effective AV value that can be derived from the open AV value table and the effective AV value of the interchangeable lens. An area for storing the difference information is provided in the buffer memory 204.

  When the dial 220 for adjusting the aperture value is operated by the user, the CPU 211 acquires an aperture value corresponding to the operation. Here, the aperture value that can be set by the user is an aperture value in 1 / 3-step increments as described above. Therefore, when the dial 220 accepts an operation from the user, the aperture value is changed between the aperture values in increments of 1/3. That is, when the current aperture value is “2.8” and the dial 220 is turned to the right, the aperture value is changed to “3.3”. When the dial 220 is further turned to the right, the aperture value is changed to “3.5”. On the other hand, when the aperture value is “3.5” and the dial 220 is turned counterclockwise, the aperture value is returned to “3.3”. At this time, the changed aperture value is displayed on the display means. Here, the settable aperture value includes an upper limit value and a lower limit value. In the present embodiment, it is “2.8 to 5.6”. However, since the effective aperture value changes according to the zoom position, the settable range of the user is determined as follows. That is, in this embodiment, since the camera body acquires the open AV value table and the zoom position, the limit value on the open side of the aperture can be predicted. Therefore, when the zoom position is “1 to 3”, the value obtained by converting the effective AV value into the aperture value is closer to “2.8” than “3.3”, and thus “2.8 to 5.6”. The aperture value can be set with “”. In the case of the zoom position “4 to 7”, the value obtained by converting the effective AV value into the aperture value is closer to “3.3” than “2.8” or “3.5”. The aperture value can be set at “3 to 5.6”. In the same way, when the zoom position is “8-9”, the aperture value can be set at “3.5-5.6”. That is, the camera body 2 has different aperture values that can be set by the user according to the state of the zoom lens.

  Returning to the description of the control of the CPU 211, the aperture value acquired by the CPU 211 is converted into an AV value by the CPU 211. When the CPU 211 acquires the AV value corresponding to the user's operation, the CPU 211 transmits a control signal for adjusting the diaphragm 307 to the lens controller 311. At this time, the CPU 211 calculates and updates difference information according to the acquired AV value. For example, as illustrated in FIG. 5, when the acquired AV value is “4.0”, the CPU 211 acquires a difference from the current (before change) effective AV value “3.4”. In this case, the difference is “0.6”. Therefore, the CPU 211 updates the difference information stored in the buffer memory 204 using the difference “0.6”.

  The CPU 211 transmits a request signal for requesting a zoom position every time image data of the CMOS sensor 201 is generated. For example, the CPU 211 reads the timing at which the image data of the CMOS sensor 201 is generated from the timing generator, and transmits a request signal. Details are as described above.

  The CPU 211 acquires the zoom position transmitted from the lens controller 311. When acquiring the zoom position, the CPU 211 calculates an effective AV value (estimated value) of the interchangeable lens using the zoom position, the open AV value table stored in the buffer memory 204, and the difference information. For example, when the acquired zoom position is “4”, the difference information is “0.6”, and the open AV value table is as shown in FIG. Based on this, an effective AV value (estimated value) is calculated. Hereinafter, the effective AV value (estimated value) is referred to as an estimated effective AV value. Specifically, as shown in FIG. 6, the CPU 211 acquires an effective AV value “3.3” when the aperture is assumed to be open, using the open AV value table and the zoom position “4”. Then, the CPU 211 calculates the estimated effective AV value “3.9” by adding the effective AV value “3.3” when the aperture is assumed to be full and the difference information “0.6”. Since the change in the AV value according to the change in the aperture state of the diaphragm is approximately proportional even when the zoom position is different, such an estimation can be performed. In the present embodiment, the calculated estimated effective AV value does not exactly match the current effective AV value of the interchangeable lens, but this embodiment can estimate at least the same value on the camera body side. There is a merit in that.

  The CPU 211 stores the estimated effective AV value calculated in this way in the buffer memory 204. The CPU 211 can appropriately perform various controls based on the stored estimated effective AV value. Various controls are not particularly limited, and can be used for, for example, the control described in the problem. As a result, the AE control such as the control described in the problem can be performed more appropriately.

[3. Correspondence with the present invention]
The digital camera 1 is an example of an imaging apparatus of the present invention. The open AV value table in FIG. 4 is an example of relationship information. The CPU 211 is an example of relationship information acquisition means, lens position acquisition means, transmission means, difference acquisition means, and estimation means. The dial 220 is an example of a reception unit.

[4. Operation)
The operation of the digital camera 1 configured as described above will be described with reference to the flowcharts of FIGS. This operation example will be described from the state in which the camera body 2 is set to the power ON and the interchangeable lens 3 is not connected.

  First, the operation when the interchangeable lens 3 is attached to the camera body 2 will be described (FIGS. 7 and 8).

  The operation of the interchangeable lens 3 will be described with reference to FIG. First, the interchangeable lens 3 is attached to the camera body 2. In this case, the lens controller 311 detects that the camera body 2 is attached to the interchangeable lens 3 (A1). When the lens controller 311 detects that the camera body 2 is attached to the interchangeable lens 3, the lens controller 311 transmits an open AV value table and a zoom position to the CPU 211 (A2). Information stored in the buffer memory 204 is read out and transmitted to the open AV value table. The zoom position is acquired from the zoom lens position detector 313 and transmitted.

  The operation of the camera body 2 will be described with reference to FIG. In the camera body 2, when the CPU 211 receives the open AV value table and the zoom position (B1), the CPU 211 stores the open AV value table in the buffer memory 204 (B2). Further, the CPU 211 calculates the current effective aperture value according to the open AV value table and the zoom position (B3). The CPU 211 stores the calculated effective aperture value in the buffer memory 204. As a result, the CPU 211 can perform exposure control of image data and wobbling control of the focus lens based on this information. The CPU 211 sets “0” to the difference information stored in the buffer memory 204 (B4).

Next, the operation when the dial 220 of the camera body 2 is operated to change the aperture value of the interchangeable lens will be described (FIGS. 9 and 10).
The operation of the camera body 2 will be described with reference to FIG. The CPU 211 detects whether or not the dial 220 has been operated (C1). When the dial 220 is operated, the CPU 211 acquires an aperture value corresponding to the operation on the dial 220. The CPU 211 transmits a control signal (control signal for adjusting the aperture) based on the acquired aperture value to the lens controller 311 (C2). The CPU 211 updates the difference information in response to this control signal (C3). The updating method is as described above.

  The operation of the interchangeable lens 3 will be described with reference to FIG. The lens controller 311 detects whether or not a control signal for adjusting the aperture is acquired from the CPU 211 (D1). When the lens controller 311 acquires a control signal for adjusting the diaphragm, the lens controller 311 adjusts the diaphragm 307 according to the control signal (D2). Specifically, the lens controller 311 responds by transmitting a drive control signal to the aperture drive unit 308. Accordingly, the aperture driving unit 308 can drive the aperture 307 based on the drive control signal.

  Next, an operation in which the interchangeable lens 3 sequentially transmits the zoom position of the zoom ring 309 to the camera body will be described (FIGS. 11 to 13).

  An operation in which the camera body 2 requests a zoom position will be described with reference to FIG. The CPU 211 detects the timing when the exposure is started by the CMOS sensor 201 (E1). When detecting the exposure start timing from the CMOS sensor 201, the CPU 211 transmits a request signal to the lens controller 311. Accordingly, the CPU 211 transmits a request signal to the lens controller 311 every time the CMOS sensor 201 generates image data.

  The operation when the interchangeable lens 3 receives the request signal will be described with reference to FIG. The lens controller 311 detects reception of a request signal from the CPU 211 (F1). When receiving the request signal, the lens controller 311 acquires the current zoom position from the zoom lens position detector 313. Then, the lens controller 311 transmits the acquired zoom position to the CPU 211 (F2). Thus, the lens controller 311 sequentially transmits the zoom position in response to a request signal received every time image data is generated.

  The operation when the camera body 2 receives the zoom position will be described with reference to FIG. The CPU 211 detects whether or not the zoom position has been received from the lens controller 311 (G1). When the CPU 211 receives the zoom position, the CPU 211 calculates the estimated effective AV value using the received zoom position, the open AV value table stored in the buffer memory 204, and the difference information (G2). The method of calculating the estimated effective AV value is as described above. Thus, the CPU 211 can estimate the effective aperture value on the camera body side even when the effective aperture value of the interchangeable lens is changed in accordance with the change of the zoom ring. In the first embodiment, it is only necessary to acquire a part of the AV value table stored in the interchangeable lens from the interchangeable lens 3, so that the information acquired from the interchangeable lens can be reduced.

  Note that the operations as shown in FIGS. 11 to 13 may be performed without performing the operations described with reference to FIGS. 9 and 10. In this case, since the difference information of the camera body has not been updated, that is, the difference information remains “0”, the estimated effective AV value is obtained using this difference information. Specifically, when the camera body 2 acquires the zoom position “8”, the estimated effective AV value “3.6” is obtained using the zoom position “8”, the open AV value table, and the difference information “0”. calculate. Thus, even when there is no operation as shown in FIGS. 9 and 10, that is, even when the zoom magnification of the interchangeable lens is not changed, the effective AV value can be calculated on the camera body side.

[5. (Summary)
The digital camera 1 includes a camera body 2 and an interchangeable lens 3. The camera body 2 includes a CPU 211 that acquires an open AV value table from the interchangeable lens 3, a CPU 211 that sequentially acquires the zoom position of the zoom lens 303 from the interchangeable lens 3, and an AV value to the interchangeable lens 3 to adjust the aperture 307. When the AV value is transmitted by the CPU 211 to be transmitted and the CPU 211, the magnitude of the difference between the open AV value table and the AV value obtained according to the zoom position acquired immediately before based on the transmitted AV value. When the CPU 211 acquires the difference information and the CPU 211 acquires the difference information and then acquires the zoom position, the interchangeable lens 3 is obtained using the difference information, the zoom position, and the acquired open AV value table. CPU 211 for estimating the current AV value of .

In this way, the camera body acquires the open AV value table and zoom position from the interchangeable lens, and estimates the AV value (effective AV value) of the interchangeable lens based on the acquired information and difference information. it can.
(Other embodiments)
Embodiment 1 was illustrated as embodiment of this invention. However, the present invention is not limited to the first embodiment, and can be implemented in other embodiments. Therefore, other embodiments of the present invention will be described collectively below.

  In the first embodiment of the present invention, a CMOS sensor is provided. However, the present invention is not limited to this. For example, a CCD image sensor may be provided. That is, the imaging means may have any configuration as long as it can capture a subject image and generate image data (digital signal or electrical signal). In addition, when it comprises with a CMOS sensor, power consumption can be reduced.

  In the first embodiment of the present invention, the lens controller 311 transmits the open AV value table to the CPU 211 when it is assumed that the aperture is adjusted to the open state. However, the lens controller may transmit a specific AV value table corresponding to the current aperture state of the diaphragm to the CPU. In this case, for example, the lens controller acquires an AV value indicating the current aperture state from the aperture. Then, assuming that the aperture is adjusted to the acquired AV value, the lens controller transmits a specific AV value table capable of obtaining an effective AV value according to the zoom position to the CPU. Specifically, when the lens controller acquires the AV value “3” of the aperture, as shown in FIG. 14, the lens controller transmits information regarding the AV value “3” to the CPU as a specific AV value table.

  In the first embodiment, the lens controller transmits the open AV value table to the CPU when the lens is mounted. However, the present invention is not limited to this, and the lens controller sends an open AV value table to the CPU when the power is turned on from OFF or when it is detected that the lens has been replaced when the power is on. It doesn't matter if you do.

  In the first embodiment, the lens controller 311 sequentially transmits the zoom position according to the request signal. However, the present invention is not limited to this, and the zoom position may be transmitted sequentially when it is detected that the zoom lens is moved. In this case, when the zoom lens is stopped, transmission of the zoom position is preferably stopped. In this way, it is possible to efficiently calculate the estimated effective aperture value while reducing the number of communications between the camera body and the interchangeable lens. The zoom lens is stopped when, for example, the lens controller acquires the zoom position from the zoom lens position detector at a predetermined timing (once every 1/30 seconds) and detects the same zoom position for a predetermined number of times. It may be determined that the zoom lens has stopped. That is, the lens controller acquires the zoom position from the zoom lens position detector at a predetermined timing. The lens controller determines that the zoom lens has stopped when the acquired zoom position is the same continuously for a predetermined number of times. In this case, the lens controller does not transmit the zoom position even when the request signal is received.

  In the first embodiment, the AV value table is used as information for obtaining the effective aperture value of the interchangeable lens. However, the present invention is not limited to this, and a mathematical expression may be used as information for obtaining the effective aperture value of the interchangeable lens. In such a case, if the numerical value when the iris is adjusted to the open state (the one that can calculate the effective AV value according to the zoom position) is transmitted as the open AV value information transmitted to the camera body as described above. Good.

  In the first embodiment, the example in which the AV value is used as the calculated value has been described. However, the present invention is not limited to this, and an aperture value may be used instead of the AV value. In this case, it can be realized by using a general relational expression between the AV value and the aperture value.

  That is, the present invention is not limited to the above embodiment, and can be implemented with various configurations.

  The present invention can be applied to a digital still camera body, a digital video camera body, and the like to which an interchangeable lens can be attached and detached.

The perspective view of the digital camera which concerns on embodiment of this invention 1 is a block diagram illustrating a configuration example of a digital camera according to an embodiment of the present invention. The figure which shows an example of the AV value table memorize | stored in the interchangeable lens 3 The figure which shows an example of the open | release AV value table transmitted to the camera main body 2 The figure for explaining the acquisition method of difference information The figure for demonstrating the calculation method of a presumed effective AV value The flowchart which shows the operation example of the interchangeable lens 3 which concerns on embodiment of this invention. The flowchart which shows the operation example of the camera main body 2 which concerns on embodiment of this invention. The flowchart which shows the operation example of the camera main body 2 which concerns on embodiment of this invention. The flowchart which shows the operation example of the interchangeable lens 3 which concerns on embodiment of this invention. The flowchart which shows the operation example of the camera main body 2 which concerns on embodiment of this invention. The flowchart which shows the operation example of the interchangeable lens 3 which concerns on embodiment of this invention. The flowchart which shows the operation example of the camera main body 2 which concerns on embodiment of this invention. The figure which shows an example of the specific AV value table which concerns on other embodiment The figure for demonstrating an example of the subject of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Digital camera 2 Camera body 3 Interchangeable lens 201 CMOS sensor 202 Shutter 203 Signal processor 204 Buffer memory 208 Body mount 209 Flash memory 210 Card slot 211 CPU
212 Shutter switch 220 Dial 301 Lens mount 303 Zoom lens 304 Focus lens 306 Focus drive unit 307 Aperture 308 Aperture drive unit 309 Zoom ring 310 Focus ring 311 Lens controller 312 Buffer memory 313 Zoom lens position detector 314 Flash memory 320 OIS drive unit 330 Gyro sensor

Claims (3)

A camera body that is detachable from an interchangeable lens having an aperture and a movable lens,
When it is assumed that the aperture is adjusted to a specific aperture diameter, relation information that can obtain information on the brightness of the interchangeable lens according to information on the lens position of the movable lens is acquired from the interchangeable lens. Relationship information acquisition means;
Lens position acquisition means for sequentially acquiring information about the lens position of the movable lens from the interchangeable lens;
Transmitting means for transmitting information about brightness to the interchangeable lens to adjust the aperture;
When information on brightness is transmitted by the transmission means, information on brightness obtained according to the acquired relation information and information on the lens position acquired immediately before based on the transmitted information on brightness Difference acquisition means for acquiring difference information regarding the magnitude of the difference between
After acquiring the difference information by the difference acquisition unit, when the information on the lens position is acquired by the lens position acquisition unit, the exchange is performed using the difference information, the information on the lens position, and the acquired relationship information. A guessing means to guess information about the current brightness of the lens;
Camera body with The camera body according to claim 1, wherein the movable lens is a zoom lens. A reception means for receiving an operation from the user;
The transmission means transmits information on brightness to the interchangeable lens in order to adjust the diaphragm according to an operation from the received user.
The camera body according to claim 1.

Images