JP2013003261A - Focus detection device and imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a focus detection device capable of shortening time for detecting a focus.SOLUTION: A focus detection device includes: a control part 103e for controlling a drive part 212 so that an optical system is focused, the control being made based on a focusing state detected by a focus detection part 103a for receiving a set of fluxes having passed through different zones of the optical system and detecting a phase difference of an object image to detect a focused state of the optical system; and a determination part 103c for determining whether either of the nearest end of the optical system and the infinity end thereof is included in a focus-detectable range calculated by a calculation part 103b configured to calculate the focus-detectable range on the basis of the aperture diameter of a diaphragm 211 and the position of a focusing lens 210b. Further, the drive part 212 is controlled in a manner that the aperture diameter of the diaphragm 211 is set at a second aperture diameter smaller than a first aperture diameter if a focused state is not detectable, so that the focusing lens 210b is driven in the direction of infinity end if the nearest end is included, or so that the focusing lens 210b is driven in the direction of the nearest end if the infinity end is included.

Description

  The present invention relates to a focus detection apparatus and an imaging apparatus.

  It is known that a focus detection range can be calculated from the current position of a focusing lens in a focus detection device that detects the focus state of an optical system. For example, Patent Document 1 describes a focus detection apparatus that performs only scanning in a direction in which the lens is extended when the position at infinity is included in the focus detectable range and the focus cannot be detected.

Japanese Patent Laid-Open No. 1-187521

  The focus detection apparatus described in Patent Document 1 must perform a normal scanning operation when the infinity position is not included in the focus detectable range, and the time required for focus detection becomes long.

According to a first aspect of the present invention, there is provided a focus adjusting device for adjusting a focus state of an optical system having a focusing lens and a diaphragm, and a driving unit that drives the focusing lens in the optical axis direction and passes through different regions of the optical system A focus detection unit that detects the phase difference of the subject image by receiving the pair of light beams and detecting the phase difference of the subject image, and the optical system is in focus based on the focus state detected by the focus detection unit A control unit that controls the drive unit to be, a calculation unit that calculates a focus detectable range of the focus detection unit based on the aperture diameter of the diaphragm and the position of the focusing lens, and focus detection calculated by the calculation unit And a determination unit that determines whether or not the possible range includes one of the near end and the infinity end of the optical system, and the control unit sets the aperture diameter of the aperture to the first aperture diameter and detects the focus Focus on the part If the focus state cannot be detected, the aperture diameter of the diaphragm is set to a second aperture diameter smaller than the first aperture diameter, and the determination unit performs the determination. If the near end is included, the distance is infinite If the infinity end is included in the end direction, the focus detection device controls the drive unit so that the focusing lens is driven in the close end direction.
An invention according to claim 5 is an imaging apparatus comprising the focus detection apparatus according to any one of claims 1 to 4.

  According to the present invention, it is possible to reduce the time required for focus detection.

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 schematic diagram which shows the detail of the holding parts 102 and 202. FIG. It is a timing chart which shows the example of command data communication. It is a timing chart which shows the example of hotline communication. 3 is an enlarged view schematically showing an imaging surface of an imaging element 104. FIG. 4 is a cross-sectional view of a focus detection pixel 320. FIG. 3 is a cross-sectional view of imaging pixels 310, 311 and 312. FIG. It is explanatory drawing of the focus detection by the pupil division system using a micro lens. It is a figure for demonstrating the detail of the focus detection calculation by the focus detection part 103a. It is a figure which shows typically an aperture value and a focus detectable range. It is a flowchart of the automatic focus adjustment process by the focusing control part 103e.

(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 1 includes a camera body 100 and an interchangeable lens 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 interchangeable lens 200 is detachably attached. At a position near the lens mount 101 of the camera body 100 (inner peripheral side of the lens mount 101), a holding part (electrical connection) that holds a contact in a state of partially protruding toward the inner peripheral side of the lens mount 101 Part) 102 is provided. The holding portion 102 is provided with a plurality of contacts.

  The interchangeable lens 200 is provided with a lens mount 201 to which the camera body 100 is detachably attached corresponding to the lens mount 101 on the body side. At a position near the lens mount 201 of the interchangeable lens 200 (inner peripheral side of the lens mount 201), a holding portion (electrical connection) that holds a contact in a state of partially protruding toward the inner peripheral side of the lens mount 201 Part) 202 is provided. The holding portion 202 is provided with a plurality of contacts.

  When the interchangeable lens 200 is attached to the camera body 100, the holding unit 102 provided with a plurality of contacts is electrically and physically connected to the holding unit 202 provided with a plurality of contacts. Both holders 102 and 202 are used for power supply from the camera body 100 to the interchangeable lens 200 and transmission / reception of signals between the camera body 100 and the interchangeable lens 200.

  An imaging element 104 such as a CMOS or CCD is provided behind the lens mount 101 in the camera body 100. In the imaging surface of the imaging element 104 of the present embodiment, focus detection pixels are incorporated together with imaging pixels. The imaging surface of the imaging element 104 will be described in detail later.

  Above the camera body 100, a button 107 serving as an input device is provided. When the camera body 100 is in a power-off state, when the user presses the button 107, the camera body 100 is in a power-on state. A button 207 similar to the button 107 is also provided on the side surface of the lens barrel of the interchangeable lens 200. When the camera body 100 is in the power-off state, when the user presses the button 207 of the interchangeable lens 200 attached to the camera body 100, the camera body 100 is in the power-on state.

  FIG. 2 is a cross-sectional view showing an interchangeable lens type camera system to which the present invention is applied. The interchangeable lens 200 includes an imaging optical system 210 that forms a subject image. The imaging optical system 210 includes a plurality of lenses 210 a to 210 c and a diaphragm 211. The plurality of lenses 210a to 210c includes a focusing lens 210b for controlling the focus position of the subject image.

  The interchangeable lens 200 is a so-called zoom lens. That is, the imaging optical system 210 has a variable focal length, and the user rotates an operation ring provided on the interchangeable lens 200 or operates an operation member such as a button provided on the camera body 100, for example. The focal length of the imaging optical system 210 can be changed by a predetermined operation such as.

  Inside the interchangeable lens 200, a lens control unit 203 that controls each part of the interchangeable lens 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 the lens side first communication unit 217, the lens side second communication unit 218, the lens driving unit 212, the lens position detection unit 213, the zoom position detection unit 214, the ROM 215, and the RAM 216.

  The lens-side first communication unit 217 and the lens-side second communication unit 218 are configured to be able to exchange signals with the camera body 100 via the communication contacts of the holding units 102 and 202. The lens side first communication unit 217 and the lens side second communication unit 218 are communication interfaces on the interchangeable lens 200 side, respectively. The lens control unit 203 performs data communication (hotline communication, command data communication) described later with the camera body 100 (a body control unit 103 described later) using these communication interfaces. The power receiving unit 230 receives the operating current of each unit including the lens control unit 203 from the camera body 100 through the power supply contact of the holding units 102 and 202 from the camera body 100.

  The lens driving unit 212 includes an actuator such as a stepping motor, for example, and drives the focusing lens 210b in accordance with a signal input to the lens driving unit 212. The focusing lens 210b is driven in the optical axis direction by the lens driving unit 212. The lens position detection unit 213 is configured by, for example, an encoder connected to the focusing lens 210b, and detects the position of the focusing lens 210b in the optical axis direction. Similarly, the zoom position detection unit 214 includes, for example, an encoder connected to a zooming lens included in the imaging optical system 210, and detects the current zoom position.

  The ROM 215 is a non-volatile storage medium, and stores a predetermined control program executed by the lens control unit 203, various tables described later, and the like. The RAM 216 is a volatile storage medium and is used as a storage area for various data by the lens control unit 203.

  A shutter 115 for controlling the exposure state of the image sensor 104 and an optical filter 116 combining an optical low-pass filter and an infrared cut filter 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.

  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. The button 107 shown in FIG. 1 is connected to the body control unit 103, and a pressing operation of the button 107 can be detected.

  A body-side first communication unit 117 and a body-side second communication unit 118 are connected to the body control unit 103. The body side first communication unit 117 and the body side second communication unit 118 are both connected to the holding unit 102, and signals can be exchanged with the interchangeable lens 200. The body side first communication unit 117 can exchange data with the lens side first communication unit 217 via a plurality of communication contacts provided in the holding unit 102. Similarly, the body side second communication unit 118 can exchange data with the lens side second communication unit 218. In other words, each of the body-side first communication unit 117 and the body-side second communication unit 118 is a body-side communication interface. The body control unit 103 performs communication (hotline communication and command data communication) described later with the interchangeable lens 200 (lens control unit 203) using these communication interfaces.

  A display device 111 configured by an LCD panel or the like is disposed on the back surface of the camera body 100. The body control unit 103 displays various menu screens for setting an image of a subject (a so-called through image) based on the output of the image sensor 104, shooting conditions, and the like on the display device 111.

  As shown in the lower part of FIG. 2, the body control unit 103 includes a focus detection unit 103a, a range calculation unit 103b, an end determination unit 103c, a drive instruction transmission unit 103d, and a focus control unit 103e in software form. These units are implemented in software by the body control unit 103 executing a predetermined control program stored in a ROM (not shown) or the like, but these units may be configured as dedicated electronic circuits. Good.

  The focus detection unit 103 a detects the focus state of the imaging optical system 210 by detecting the phase difference of the subject image from the output of the focus detection pixel array of the image sensor 104. The range calculation unit 103b calculates the focus detectable range of the focus detection unit 103a based on the aperture diameter of the diaphragm 211 and the position of the focusing lens 210b. The end determination unit 103c determines whether or not the end of the imaging optical system 210 (one of the closest end and the infinite end) is included in the focus detectable range calculated by the range calculation unit 103b. The drive instruction sending unit 103d sends a drive instruction for the focusing lens 210b to the interchangeable lens 200 via the body-side first communication unit 117. When receiving the driving instruction, the lens control unit 203 drives the focusing lens 210b according to the driving instruction. The focus control unit 103e controls the drive instruction sending unit 103d so that the imaging optical system 210 is in a focused state based on the focus state detected by the focus detection unit 103a.

(Description of holding units 102 and 202)
FIG. 3 is a schematic diagram showing details of the holding units 102 and 202. In FIG. 3, the holding portion 102 is arranged on the right side of the lens mount 101 in accordance with the actual mount structure. That is, the holding portion 102 of the present embodiment is disposed at a location deeper than the mount surface of the lens mount 101 of the camera body 100 (a location on the right side of the lens mount 101 in FIG. 3). Similarly, the holding unit 202 is arranged on the right side of the lens mount 201 because the holding unit 202 of this embodiment is arranged at a position protruding from the mount surface of the lens mount 201 of the interchangeable lens 200. Represents. Since the holding unit 102 and the holding unit 202 are arranged in this way, when the mount surface of the lens mount 101 and the mount surface of the lens mount 201 are brought into contact with each other, the camera body 100 and the interchangeable lens 200 are mounted and coupled. The holding part 102 and the holding part 202 are connected, and the electrical contacts provided in both holding parts are also connected. Since such a mount structure is well known, further explanation and illustration are omitted.

  As shown in FIG. 3, the holding unit 102 has 12 contacts BP <b> 1 to BP <b> 12. The holding unit 202 has twelve contacts LP1 to LP12 corresponding to the twelve contacts described above.

  The contact BP1 and the contact BP2 are connected to the power transmission unit 130 in the camera body 100. The power transmission unit 130 supplies the operating voltage of each part in the interchangeable lens 200 excluding a circuit (such as the lens driving unit 212) having a driving system such as an actuator and a relatively large power consumption to the contact point BP1. That is, the operating voltage of each part in the interchangeable lens 200 excluding the above driving parts is supplied from the contact BP1 and the contact LP1. The voltage value that can be supplied to the contact point BP1 has a range between the minimum voltage value and the maximum voltage value (for example, a voltage width in the 3V range). The voltage value that is normally supplied is the maximum voltage value and the minimum voltage value. Is a voltage value in the vicinity of the intermediate value. As a result, the current value supplied from the camera body 100 side to the interchangeable lens 200 side is a current value within a range of about several tens of mA to several hundreds of mA in the power-on state.

  The contact BP2 is a ground terminal corresponding to the operating voltage given to the contact BP1. That is, the contact BP2 and the contact LP2 are ground terminal voltages corresponding to the above operating voltage. The contact LP1 and the contact LP2 are connected to the power receiving unit 230 in the interchangeable lens 200. The power receiving unit 230 supplies the power supplied from the camera body 100 to each unit in the interchangeable lens 200 including the lens control unit 203.

  In the following description, the signal line constituted by the contact point BP1 and the contact point LP1 is referred to as a signal line V33. A signal line constituted by the contact point BP2 and the contact point LP2 is referred to as a signal line GND. These contacts LP1, LP2, BP1, BP2 constitute a power supply system contact for supplying power from the camera body 100 side to the interchangeable lens 200 side.

  The contacts BP3, BP4, BP5, and BP6 are connected to the body-side first communication unit 117. The contact points LP3, LP4, LP5, and LP6 on the interchangeable lens 200 side corresponding to these contact points are connected to the lens-side first communication unit 217. The body-side first communication unit 117 and the lens-side first communication unit 217 transmit and receive data to and from each other using these contact points (communication system contact points). The contents of communication performed by the body-side first communication unit 117 and the lens-side first communication unit 217 will be described in detail later.

  In the following description, a signal line constituted by the contact BP3 and the contact LP3 is referred to as a signal line CLK. Similarly, the signal line constituted by the contact BP4 and the contact LP4 is signal line BDAT, the signal line constituted by the contact BP5 and the contact LP5 is signal line LDAT, and the signal line constituted by the contact BP6 and the contact LP6 is signaled. Called line RDY.

  The contacts BP7, BP8, BP9, and BP10 are connected to the body-side second communication unit 118. The contacts LP7, LP8, LP9, and LP10 on the interchangeable lens 200 side corresponding to these contacts are connected to the lens-side second communication unit 218. The lens-side second communication unit 218 transmits data to the body-side second communication unit 118 using these contacts (communication system contacts). The contents of communication performed by the body-side second communication unit 118 and the lens-side second communication unit 218 will be described in detail later.

  In the following description, a signal line constituted by the contact BP7 and the contact LP7 is referred to as a signal line HREQ. Similarly, a signal line composed of the contact point BP8 and the contact point LP8 is signal line HANS, a signal line composed of the contact point BP9 and the contact point LP9 is signal line HCLK, and a signal line composed of the contact point BP10 and the contact point LP10 is signaled. Called line HDAT.

  The contact BP11 and the contact BP12 are connected to the power supply circuit 140 in the camera body 100. The power supply circuit 140 supplies, to the contact point BP12, a driving voltage of a circuit (such as the lens driving unit 212) having a driving system such as an actuator and having relatively large power consumption. That is, the driving voltage of each driving unit is supplied from the contact point BP12 and the contact point LP12. The voltage value that can be supplied to the contact point BP12 has a range from the minimum voltage value to the maximum voltage value, all of which are larger than the voltage value range that can be supplied to the contact point BP1 (for example, The maximum voltage value that can be supplied to the contact point BP12 is several times the maximum voltage value that can be supplied to the contact point BP1). That is, the voltage value supplied to the contact point BP12 is a voltage value whose magnitude is different from the voltage value supplied to the contact point BP1. The voltage value that is normally supplied to the contact BP12 is a voltage value in the vicinity of an intermediate value between the maximum voltage value and the minimum voltage value that can be supplied to the contact BP12. Thus, the current supplied from the camera body 100 side to the interchangeable lens 200 side has a current value of about 10 mA to several A in the power-on state.

  The contact BP11 is a ground terminal corresponding to the drive voltage given to the contact BP12. That is, the contact BP11 and the contact LP11 are ground terminals corresponding to the drive voltage.

  In the following description, a signal line constituted by the contact BP11 and the contact LP11 is referred to as a signal line PGND. A signal line constituted by the contact BP12 and the contact LP12 is referred to as a signal line BAT. These contacts LP11, LP12, BP11, BP12 constitute a power supply system contact for supplying power from the camera body 100 side to the interchangeable lens 200 side.

  As is apparent from the magnitude relationship between the voltage value (current value) supplied to the contacts BP12 and LP12 and the voltage value (current value) supplied to the contacts BP1 and LP1, the voltages are supplied to the contacts. The difference between the maximum value and the minimum value of the current flowing through the contact point BP11 and the contact point LP11 serving as the ground terminals for each of the voltages is larger than the difference between the maximum value and the minimum value of the current flowing through the contact point BP2 and the contact point LP2. ing. This is because the power consumed by each drive unit having a drive system such as an actuator is larger than that of an electronic circuit such as the lens control unit 203 in the interchangeable lens 200 and it is not necessary to drive the driven member. This is because each drive unit does not consume power.

(Description of command data communication)
The lens control unit 203 controls the lens-side first communication unit 217 and receives control data from the body-side first communication unit 117 via the contacts LP3 to LP6, that is, the signal lines CLK, BDAT, LDAT, and RDY. Reception and transmission of response data to the body-side first communication unit 117 are performed in parallel at a first predetermined cycle (for example, 16 milliseconds in this embodiment). Hereinafter, details of communication performed between the lens-side first communication unit 217 and the body-side first communication unit 117 will be described.

  In the present embodiment, communication performed between the lens control unit 203 and the lens-side first communication unit 217 and the body control unit 103 and the body-side first communication unit 117 is referred to as “command data communication”. A transmission line composed of four signal lines (signal lines CLK, BDAT, LDAT, and RDY) used for command data communication is referred to as a first transmission line.

  FIG. 4 is a timing chart showing an example of command data communication. The body control unit 103 and the body-side first communication unit 117 first check the signal level of the signal line RDY at the start of command data communication (T1). The signal level of the signal line RDY indicates whether the lens-side first communication unit 217 can communicate. That is, a communication availability signal indicating availability of data communication is output from the lens side first communication unit 217 to the signal line RDY. The lens control unit 203 and the lens-side first communication unit 217 output a signal of H (High) level from the contact LP6 when communication is not possible. That is, the signal level of the signal line RDY is set to H level. When the signal line RDY is at the H level, the body control unit 103 and the body-side first communication unit 117 do not start communication until the signal line RDY is at the L level. Also, the next processing during communication is not executed.

  If the signal line RDY is at L (Low) level, the body control unit 103 and the first body side communication unit 117 output the clock signal 401 from the contact point BP3. That is, the clock signal 401 is transmitted to the first lens side communication unit 217 via the signal line CLK. In synchronization with the clock signal 401, the body control unit 103 and the body side first communication unit 117 output a body side command packet signal 402, which is the first half of the control data, from the contact point BP4. That is, the body side command packet signal 402 is transmitted to the first lens side communication unit 217 via the signal line BDAT.

  When the clock signal 401 is output to the signal line CLK, the lens control unit 203 and the lens-side first communication unit 217 synchronize with the clock signal 401, and the lens-side command packet that is the first half of the response data from the contact LP5. The signal 403 is output. That is, the lens-side command packet signal 403 is transmitted to the first body-side communication unit 117 via the signal line LDAT.

  The lens control unit 203 and the lens side first communication unit 217 set the signal level of the signal line RDY to the H level in response to the completion of transmission of the lens side command packet signal 403 (T2). The lens control unit 203 starts a first control process 404 (described later) that is a process according to the content of the received body-side command packet signal 402.

  When the first control process 404 is completed, the lens control unit 203 notifies the lens side first communication unit 217 of the completion of the first control process 404. In response to this notification, the lens side first communication unit 217 outputs an L level signal from the contact LP6. That is, the signal level of the signal line RDY is set to L level (T3). The body control unit 103 and the first body side communication unit 117 output the clock signal 405 from the contact point BP3 in accordance with the change in the signal level. That is, the clock signal 405 is transmitted to the lens side first communication unit 217 via the signal line CLK.

  The body control unit 103 and the first body-side communication unit 117 output a body-side data packet signal 406 that is the latter half of the control data from the contact point BP4 in synchronization with the clock signal 405. That is, the body side data packet signal 406 is transmitted to the lens side first communication unit 217 via the signal line BDAT.

  Further, when the clock signal 405 is output to the signal line CLK, the lens control unit 203 and the lens side first communication unit 217 synchronize with the clock signal 405, and the lens which is the latter half of the response data from the contact LP5 receives the data packet signal. 407 is output. That is, the lens-side data packet signal 407 is transmitted to the first body-side communication unit 117 via the signal line LDAT.

  In response to the completion of transmission of the lens-side data packet signal 407, the lens control unit 203 and the lens-side first communication unit 217 set the signal level of the signal line RDY to the H level again (T4). The lens control unit 203 starts a second control process 408 (described later) that is a process according to the content of the received body-side data packet signal 406.

  As described above, the lens-side first communication unit 217 includes the signal line CLK from which the clock signal is output from the camera body 100, the signal line BDAT from which the data signal is output from the camera body 100 in synchronization with the clock signal, A signal line LDAT from which a data signal is output in synchronization with the clock signal from the lens-side first communication unit 217, and a communication enable / disable signal indicating whether data communication from the lens-side first communication unit 217 to the lens-side first communication unit 217 is possible. Is communicated with the camera body 100 using the signal line RDY from which is output.

  Here, the first control process 404 and the second control process 408 performed by the lens control unit 203 will be described.

  For example, a case where the received body-side command packet signal 402 has a content requesting specific data on the interchangeable lens side will be described. As the first control process 404, the lens control unit 203 analyzes the content of the command packet signal 402 and executes a process of generating the requested specific data. Further, as the first control process 404, the lens control unit 203 uses the checksum data included in the command packet signal 402 to easily determine whether there is an error in the communication of the command packet signal 402 from the number of data bytes. The communication error check process to check is also executed. The specific data signal generated in the first control process 404 is output to the body side as a lens-side data packet signal 407. In this case, the body side data packet signal 406 output from the body side after the command packet signal 402 is a dummy data signal (including checksum data) that has no particular meaning for the lens side. In this case, the lens control unit 203 executes the communication error check process as described above using the checksum data included in the body side data packet signal 406 as the second control process 408.

  For example, a case where the received body-side command packet signal 402 is an instruction to drive a lens-side driven member will be described. For example, a case where the command packet signal 402 is an instruction to drive the focusing lens 210b and the received body side data packet signal 406 is the driving amount of the focusing lens 210b will be described. As the first control process 404, the lens control unit 203 analyzes the content of the command packet signal 402 and generates an acknowledgment signal indicating that the content has been understood. Furthermore, the lens control unit 203 also executes the communication error check process as described above using the checksum data included in the command packet signal 402 as the first control process 404. The acknowledge signal generated in the first control process 404 is output to the body side as a lens side data packet signal 407. In addition, as the second control process 408, the lens control unit 203 executes an analysis process of the contents of the body side data packet signal 406 and uses the checksum data included in the body side data packet signal 406 as described above. Execute the check process.

  When the second control process 408 is completed, the lens control unit 203 notifies the lens side first communication unit 217 of the completion of the second control process 408. Accordingly, the lens control unit 203 causes the lens side first communication unit 217 to output an L level signal from the contact LP6. That is, the signal level of the signal line RDY is set to L level (T5).

  If the received body-side command packet signal 402 is an instruction to drive the lens-side driven member (for example, the focusing lens 210b) as described above, the lens control unit 203 notifies the lens-side first communication unit 217. While the signal level of the signal line RDY is set to L level, the lens driving unit 212 is caused to execute processing for driving the focusing lens 210b by the driving amount.

  The communication performed at the above-described time T1 to time T5 is one command data communication. As described above, in one command data communication, body control unit 103 and body side first communication unit 117 transmit body side command packet signal 402 and body side data packet signal 406 one by one. In other words, the body side command packet signal 402 and the body side data packet signal 406 together constitute one control data although it is divided and transmitted for convenience of processing.

  Similarly, in one command data communication, the lens control unit 203 and the lens side first communication unit 217 transmit the lens side command packet signal 403 and the lens side data packet signal 407 one by one. That is, the lens side command packet signal 403 and the lens side data packet signal 407 are combined to form one response data.

  As described above, the lens control unit 203 and the lens-side first communication unit 217 perform reception of control data from the body-side first communication unit 117 and transmission of response data to the body-side first communication unit 117 in parallel. And do it. The contact LP6 and the contact BP6 used for command data communication are contacts through which asynchronous signals (signal level of the signal line RDY / H (High) level or L (Low) level) that are not synchronized with other clock signals are transmitted. is there.

(Description of hotline communication)
The lens control unit 203 controls the lens side second communication unit 218 to transmit lens position data to the body side second communication unit 118 via the contacts LP7 to LP10, that is, the signal lines HREQ, HANS, HCLK, and HDAT. Send. Hereinafter, details of communication performed between the lens-side second communication unit 218 and the body-side second communication unit 118 will be described.

  In the present embodiment, communication performed between the lens control unit 203 and the lens-side second communication unit 218, and the body control unit 103 and the body-side second communication unit 118 is referred to as “hotline communication”. A transmission line composed of four signal lines (signal lines HREQ, HANS, HCLK, and HDAT) used for hot line communication is referred to as a second transmission line.

  FIG. 5 is a timing chart showing an example of hotline communication. The body control unit 103 of the present embodiment is configured to start hot line communication every second predetermined period (for example, 1 millisecond in the present embodiment). This period is shorter than the period for performing command data communication. FIG. 5A is a diagram illustrating a state in which hot line communication is repeatedly performed at predetermined intervals Tn. FIG. 5B shows a state in which a certain communication period Tx is expanded in hot line communication repeatedly executed. Hereinafter, the procedure of hotline communication will be described based on the timing chart of FIG.

  At the start of hot line communication (T6), body control unit 103 and body-side second communication unit 118 first output an L level signal from contact point BP7. That is, the signal level of the signal line HREQ is set to L level. The lens side second communication unit 218 notifies the lens control unit 203 that this signal has been input to the contact LP7. In response to this notification, the lens control unit 203 starts executing a generation process 501 that generates lens position data. The generation process 501 is a process in which the lens control unit 203 causes the lens position detection unit 213 to detect the position of the focusing lens 210b and generates lens position data representing a detection result.

  When the lens control unit 203 completes the generation process 501, the lens control unit 203 and the lens-side second communication unit 218 output an L level signal from the contact LP8 (T7). That is, the signal level of the signal line HANS is set to the L level. The body control unit 103 and the body-side second communication unit 118 output the clock signal 502 from the contact BP9 in response to the input of this signal to the contact BP8. That is, a clock signal is transmitted to the lens side second communication unit 218 via the signal line HCLK.

  The lens control unit 203 and the second lens-side communication unit 218 output a lens position data signal 503 representing lens position data from the contact LP10 in synchronization with the clock signal 502. That is, the lens position data signal 503 is transmitted to the body-side second communication unit 118 via the signal line HDAT.

  When the transmission of the lens position data signal 503 is completed, the lens control unit 203 and the second lens side communication unit 218 output an H level signal from the contact LP8. That is, the signal level of the signal line HANS is set to the H level (T8). The body-side second communication unit 118 outputs an H-level signal from the contact LP7 in response to the input of this signal to the contact BP8. That is, the signal level of the signal line HREQ is set to H level (T9).

  The communication performed from time T6 to time T9 described above is one hot line communication. As described above, in one hot line communication, one lens position data signal 503 is transmitted by the lens control unit 203 and the second lens side communication unit 218. The contacts LP7, LP8, BP7, and BP8 used for hotline communication are contacts through which asynchronous signals that are not synchronized with other clock signals are transmitted. That is, the contacts LP7 and BP7 are contacts through which an asynchronous signal (signal level HREQ signal level / H (High) level or L (Low) level) is transmitted, and the contacts LP8 and BP8 are asynchronous signals (signal line HANS). Signal level / H (High) level or L (Low) level).

  Note that the command data communication and the hotline communication can be executed simultaneously or partially in parallel. That is, one of the lens side first communication unit 217 and the lens side second communication unit 218 can communicate with the camera body 100 even when the other is communicating with the camera body 100. is there.

(Description of focus detection pixels)
FIG. 6 is an enlarged view schematically showing the imaging surface of the imaging element 104. The imaging pixels are composed of three types of pixels, ie, a green pixel 310, a red pixel 311, and a blue pixel 312. These pixels are two-dimensionally arranged in a Bayer array. The imaging pixels (green pixel 310, red pixel 311 and blue pixel 312) are each a microlens, a photoelectric conversion unit, and color filters (not shown) (red (R), green (G), and blue (B)). Type).

  In FIG. 6, the focus detection pixels 320 are continuously arranged in the row direction (lateral direction in FIG. 6) to form a focus detection region. The array of focus detection pixels 320 is surrounded by imaging pixels. There are a plurality of focus detection areas formed in this manner on the imaging surface of the imaging element 104. That is, there are a plurality of sets of focus detection pixels 320 continuously arranged in the row direction. Note that there is an area where the focus detection pixels 320 are arranged in the column direction (vertical direction in FIG. 6), but such an area is obtained by rotating 90 degrees clockwise in FIG. The description is omitted.

  FIG. 7 is a cross-sectional view of the focus detection pixel 320. FIG. 7A is a cross-sectional view as seen from the incident direction side (optical system side) of the subject light, and FIG. 7B is a cross-sectional view as seen from the lateral direction (paper side in FIG. 2). Each of the focus detection pixels 320 includes the microlens 10 and a pair of photoelectric conversion units 12 and 13. In the focus detection pixel 320, the microlens 10 is disposed in front of the focus detection photoelectric conversion units 12 and 13, and the photoelectric conversion units 12 and 13 are projected forward by the microlens 10. The photoelectric conversion units 12 and 13 are formed on the semiconductor circuit substrate 29.

  FIG. 8 is a cross-sectional view of the imaging pixels 310, 311, and 312. FIG. 8A is a cross-sectional view seen from the incident direction side (optical system side) of the subject light, and FIG. 8B is a cross-sectional view seen from the lateral direction (the paper surface side in FIG. 2). The imaging pixels 310, 311, and 312 each include a microlens 10 and an imaging photoelectric conversion unit 11. In the imaging pixels 310, 311, and 312, the micro lens 10 is disposed in front of the imaging photoelectric conversion unit 11, and the photoelectric conversion unit 11 is projected forward by the micro lens 10. The photoelectric conversion unit 11 is formed on the semiconductor circuit substrate 29. A color filter (not shown) is disposed between the microlens 10 and the photoelectric conversion unit 11.

  The photoelectric conversion unit 11 of the imaging pixels 310, 311, 312 is designed to have a shape that receives all the light flux having a predetermined aperture diameter (for example, F1.0) by the microlens 10. On the other hand, the pair of photoelectric conversion units 12 and 13 of the focus detection pixel 320 are designed in such a shape that the microlens 10 receives all light beams having a predetermined aperture diameter (for example, F2.8).

(Description of focus state detection processing by the focus detection unit 103a)
FIG. 9 is an explanatory diagram of focus detection by a pupil division method using a microlens. The microlenses 50 and 60 of the focus detection pixels are disposed in the vicinity of the planned imaging plane of the imaging optical system 210. The microlens 50 projects the shape of the pair of photoelectric conversion units 52 and 53 disposed behind the microlens 50 onto the exit pupil 90 that is separated from the microlenses 50 and 60 by the projection distance d0. , 93 are formed. The projection distance d0 is a distance determined according to the curvature and refractive index of the microlens, the distance between the microlens and the photoelectric conversion unit, and is hereinafter referred to as a distance measurement pupil distance. The microlens 60 projects the shape of the pair of photoelectric conversion units 62 and 63 disposed behind the microlens 60 onto the exit pupil 90 separated by a projection distance (distance pupil distance) d0. , 93 are formed. That is, the projection direction of each pixel is determined so that the projection shapes (ranging pupils 92 and 93) of the photoelectric conversion units of the focus detection pixels coincide on the exit pupil 90 at the projection distance d0. That is, the pair of distance measuring pupils 92 and 93, the pair of photoelectric conversion units 52 and 53, and the pair of photoelectric conversion units 62 and 63 have a conjugate relationship via the microlenses 50 and 60.

  In FIG. 9, for convenience, focus detection pixels (comprising a microlens 50 and a pair of photoelectric conversion units 52 and 53) on the optical axis and adjacent focus detection pixels (a microlens 60 and a pair of photoelectric conversions) are shown. (Converters 62 and 63) are schematically illustrated. However, even when the focus detection pixel is located at a position away from the optical axis around the screen, the pair of photoelectric conversion units is each a pair of distance measuring units. A light beam arriving at each microlens from the pupil is received. The arrangement direction of the focus detection pixels 320 is made to coincide with the arrangement direction of the pair of distance measuring pupils, that is, the arrangement direction of the pair of photoelectric conversion units.

  The photoelectric conversion unit 52 outputs a signal corresponding to the intensity of the image formed on the microlens 50 by the focus detection light beam 72 passing through the distance measuring pupil 92 and directed to the microlens 50. The photoelectric conversion unit 53 passes through the distance measuring pupil 93 and outputs a signal corresponding to the intensity of the image formed on the microlens 50 by the focus detection light beam 73 directed to the microlens 50. The photoelectric conversion unit 62 outputs a signal corresponding to the intensity of the image formed on the microlens 60 by the focus detection light beam 82 passing through the distance measuring pupil 92 and directed to the microlens 60. The photoelectric conversion unit 63 outputs a signal corresponding to the intensity of the image formed on the microlens 60 by the focus detection light beam 83 passing through the distance measuring pupil 93 and directed to the microlens 60.

  A plurality of focus detection pixels as described above are arranged in a straight line, and the output of a pair of photoelectric conversion units of each pixel is grouped into an output group corresponding to the distance measurement pupil 92 and the distance measurement pupil 93, whereby the distance measurement pupil Information on the intensity distribution of a pair of images formed on a focus detection pixel array by a focus detection light beam (a pair of light beams that have passed through different regions of the imaging optical system 210) that respectively pass through the lens 92 and the distance measuring pupil 93 is obtained. . By performing image shift detection calculation processing (correlation calculation processing, phase difference detection processing), which will be described later, on these pieces of information, the amount of image shift between a pair of images is detected by a so-called pupil division type phase difference detection method. Furthermore, by performing a conversion calculation according to the center of gravity distance of the pair of distance measuring pupils to the image shift amount, the current imaging plane with respect to the planned imaging plane (the focal point corresponding to the position of the microlens array on the planned imaging plane) The deviation (defocus amount) of the imaging plane at the detection position is calculated. The focus detection unit 103a detects the focus state of the imaging optical system 210 by performing the above calculation.

  In the above description, the range-finding pupil has been described as being not limited (not broken) by the aperture limiting element (aperture aperture, lens outer shape, hood, etc.) of the interchangeable lens. When the distance measuring pupil is limited by the above, the photoelectric conversion unit of the focus detection pixel receives the light beam passing through the limited distance measuring pupil as the focus detection light beam.

FIG. 10 is a diagram for explaining the details of the focus detection calculation by the focus detection unit 103a. A pair of data strings (α1 to αM, β1 to βM, where M is the number of data) output from the focus detection pixel column is subjected to a high frequency cut filter process as shown in the following equation (1) to obtain a first data string By generating (A1 to AN) and the second data sequence (B1 to BN), noise components and high frequency components that adversely affect the correlation processing are removed from the data sequence.
An = αn + 2 × α (n + 1) + α (n + 2),
Bn = βn + 2 × β (n + 1) + β (n + 2) (1)

  In the above formula (1), n = 1 to N. Further, α1 to αM correspond to image data of an image formed by the focus detection light beam passing through the distance measuring pupil 92 in FIG. Corresponds to data. Note that this processing can be omitted when the calculation time is shortened or when it is known that the high-frequency component is small because the focus is already largely defocused.

Next, the correlation calculation shown in the following equation (2) is performed on the data strings An and Bn, and the correlation amount C (k) is calculated.
C (k) = Σ | An−B (n + k) | (2)

  In the above-described equation (2), the Σ operation is a total operation accumulated for n. The range of n is limited to a range in which data of An and Bn + k exists according to the shift amount k. The shift amount k is an integer and is a relative shift amount with the data interval (pixel pitch) of the data string as a unit. As shown in FIG. 10A, the calculation result of the expression (2) indicates that the correlation amount C (k) is the amount of shift with high correlation between a pair of data (k = k j = 2 in FIG. 10A). Minimal (the smaller the value, the higher the degree of correlation).

Next, a shift amount x that gives a minimum value C (x) with respect to the continuous correlation amount is obtained using a three-point interpolation method according to the following equations (3) to (6).
x = k j + D / SLOP (3),
C (x) = C (k j) − | D | (4),
D = {C (kj-1) -C (kj + 1)} / 2 (5),
SLOP = MAX {C (kj + 1) -C (kj), C (kj-1) -C (kj)} (6)

  Whether or not the shift amount x calculated by the above equation (3) is reliable is determined as follows. As shown in FIG. 10B, when the degree of correlation between a pair of data is low, the value of the interpolated correlation minimum value C (x) becomes large. Accordingly, when C (x) is equal to or greater than a predetermined threshold value, it is determined that the calculated shift amount has low reliability, and the calculated shift amount x is canceled. Alternatively, in order to normalize C (x) with the contrast of data, when the value obtained by dividing C (x) by SLOP that is proportional to the contrast is equal to or greater than a predetermined value, the reliability of the calculated shift amount Is determined to be low, and the calculated shift amount x is canceled. Furthermore, when SLOP which is a value proportional to contrast is equal to or smaller than a predetermined value, it is determined that the subject has low contrast and the reliability of the calculated shift amount is low, and the calculated shift amount x is canceled. . As shown in FIG. 10C, when the correlation between the pair of data is low and there is no drop in the correlation amount C (x) between the shift ranges kmin to kmax, the minimum value C (x) is obtained. In such a case, it is determined that the focus cannot be detected.

When it is determined that the calculated shift amount x is reliable, the defocus amount DEF of the subject image plane with respect to the planned image formation plane can be obtained by the following equation (7).
DEF = KX · PY · x (7)

  In the above equation (7), PY is the detection pitch (the pitch of the focus detection pixels), and KX is the size of the opening angle of the center of gravity of the light beam passing through the pair of distance measurement pupils (the distance measurement pupil center distance and the measurement distance). It is a conversion coefficient determined by (the pupil distance).

(Description of automatic focus adjustment operation)
In the camera 1, automatic focus adjustment is performed by the focus control unit 103 e in the body control unit 103. For example, automatic focus adjustment is started by a user operation, automatic control by the body control unit 103, or the like. The automatic focus adjustment may be performed when a so-called through image is displayed on the display device 111, or may be performed when a moving image is captured or immediately before a still image is captured.

  The camera 1 of the present embodiment performs automatic focus adjustment with a photographing aperture. For example, in the aperture priority auto mode, if the user has set the photographing aperture to F4, when performing automatic focus adjustment, the focusing control unit 103e first controls the aperture diameter of the aperture 211 to a diameter corresponding to F4. The focus detection unit 103a performs focus detection. However, if the aperture diameter is too small, the amount of light necessary for focus detection cannot be obtained, so a predetermined lower limit (for example, F5.6) is set. If the photographing aperture value is larger than this lower limit value (that is, if the aperture diameter is smaller than the predetermined diameter), the focus control unit 103e drives the aperture 211 to this lower limit value, and then the focus detection unit 103a detects the focus state. Let Hereinafter, the opening diameter set here is referred to as a first opening diameter.

  When the aperture 211 is set to the first aperture diameter, the focus detection unit 103a may not be able to detect the focus state depending on the contrast of the subject and the current position of the focusing lens 210b. This means that the defocus amount DEF is not calculated because it is determined that the reliability of the shift amount x described above is low. If the defocus amount DEF is calculated, the focus control unit 103e drives the focusing lens 210b to the focus position based on the calculated defocus amount DEF. As a result, the imaging optical system 210 is brought into focus and the automatic focus adjustment is completed. On the other hand, when the focus state cannot be detected, the focusing control unit 103e first drives the diaphragm 211 to the second opening diameter larger than the first opening diameter (smaller opening diameter). That is, the diaphragm 211 is in a more narrowed state.

  In the present embodiment, the second aperture diameter is the smallest aperture diameter (largest aperture value) that allows focus detection. The second aperture diameter may be different depending on the relative position in the imaging range of the focus detection area that is the target of focus adjustment (for performing focus detection). For example, if focus detection is performed in a focus detection region located near the optical axis (near the center of the imaging range), the second aperture diameter is smaller than the focus detection region located near the end of the imaging range (aperture stop). It is possible to increase the value). In addition, when the focus adjustment is not performed on a specific focus detection area but an appropriate area is automatically selected from a large number of focus detection areas, the aperture diameter is limited to the largest of the many focus detection areas. Will be matched to strict ones.

  Here, the focus control unit 103e causes the focus detection unit 103a to detect the focus state again, and checks whether or not the defocus amount DEF is calculated. The reason why the focus state is detected again after setting to the second aperture diameter is that the focus state may be detected this time even if the focus state cannot be detected at the time of the previous focus detection. This is based on the fact that the detectable range of the defocus amount DEF is wider than that at the previous focus detection because the stop 211 is narrower than the first aperture diameter at the previous focus detection.

  FIG. 11 is a diagram schematically showing the aperture diameter of the diaphragm 211 and the focus detectable range. A range 90A shown in FIG. 11 is a focus detectable range when the diaphragm 211 is set to the first aperture diameter, and a range 90B is set to an aperture diameter smaller than the first aperture diameter and larger than the second aperture diameter. The focus detection range and the range 90C are the focus detection possible range when the second aperture diameter is set. As described above, the focus-detectable range increases as the aperture 211 is reduced (as the aperture diameter of the aperture 211 decreases).

  The range calculation unit 103b calculates the focus detectable range based on the aperture diameter of the diaphragm 211 and the current position of the focusing lens 210b. These pieces of information are acquired from the lens control unit 203 as necessary by command data communication, hotline communication, or the like.

  If the focus state can be detected in the second focus detection (if the defocus amount DEF is calculated), the focusing control unit 103e adjusts the focusing lens 210b based on the defocus amount DEF. Drive to the focal position. As a result, the imaging optical system 210 is brought into focus and the automatic focus adjustment is completed. If the defocus amount DEF is not calculated even in the second focus detection, the focus control unit 103e focuses while driving the focusing lens 210b within a certain range (for example, from the closest end to the infinity end). It is necessary to perform a so-called scanning operation in which detection is repeatedly performed.

  When starting the scanning operation, the focusing control unit 103e first causes the range calculation unit 103b to calculate the focus detectable range of the focus detection unit 103a at the current aperture diameter (second aperture diameter). Then, the end determination unit 103c determines whether one of the close end and the infinity end of the imaging optical system 210 is included in the calculated focus detectable range.

  As shown in the range 90C of FIG. 11, if the infinitely far end is included in the focus detectable range calculated here, the focus detecting unit 103a at this point of time from the infinitely far end of the focusing lens 210b. It should be possible to detect the focus state for the range up to the current position. Nevertheless, the defocus amount DEF is not calculated here. Therefore, the focusing control unit 103e assumes that there is no in-focus position (the position of the focusing lens 210b that is in the in-focus state) in the range from the infinity end to the current position, and directs the scanning operation toward the nearest end. Do it. That is, the drive instruction sending unit 103d is controlled so that the focusing lens 210b is driven in the direction toward the closest end.

  In other words, the focus control unit 103e drives the focusing lens 210b in the direction of the infinity end when the end determination unit 103c determines that the close focus range is included in the focus detectable range, and the infinite end When it is determined that the far end is included, the focusing lens 210b is driven in the direction of the closest end. When the calculated focus detectable range includes neither the near end nor the infinity end, the focus control unit 103e performs a scanning operation in a predetermined direction (for example, the direction of the close end). Do.

  FIG. 12 is a flowchart of automatic focus adjustment processing by the focus control unit 103e. This processing is performed by the body control unit 103 executing a control program stored in a storage medium (not shown) (for example, a ROM such as a flash memory). Note that automatic focus adjustment may be performed by an electronic circuit or the like configured to execute processing similar to this processing.

  First, in step S100, the focus control unit 103e transmits an instruction to the lens control unit 203 so that the aperture diameter of the diaphragm 211 becomes a diameter corresponding to the photographing diaphragm (first aperture diameter). This instruction is transmitted by command data communication. In step S110, the focus detection unit 103a detects the focus state of the imaging optical system 210. In step S120, the focus control unit 103e determines whether or not a sufficiently reliable focus state has been detected. If the focus state can be detected, the process proceeds to step S220, the focusing lens 210b is driven based on the focus state (defocus amount DEF) detected by the drive instruction sending unit 103d, and the automatic focus adjustment process ends. On the other hand, if the focus state cannot be detected, the process proceeds to step S130.

  In step S130, as in step S100, the focus control unit 103e instructs the lens control unit 203 so that the aperture diameter of the diaphragm 211 becomes the aperture diameter (second aperture diameter) corresponding to the focus detection area to be focused. Send. In step S140, the focus detection unit 103a detects the focus state of the imaging optical system 210 again.

  In step S150, the focus control unit 103e determines whether or not a sufficiently reliable focus state has been detected. If the focus state can be detected, the process proceeds to step S210. In step S <b> 210, the focus control unit 103 e transmits an instruction to drive the aperture 211 to return the aperture 211 to the imaging aperture (first aperture diameter) to the lens control unit 203. In step S220, the focusing lens 210b is driven, and the automatic focus adjustment process ends. On the other hand, if the focus state cannot be detected in step S150, the process proceeds to step S160.

  In step S160, the range calculation unit 103b calculates the focus detectable range of the focus detection unit 103a. In step S <b> 170, as in step S <b> 210, the focus control unit 103 e transmits an instruction to drive the aperture 211 to return the aperture 211 to the imaging aperture (first aperture diameter) to the lens control unit 203. In step S180, the end determination unit 103c determines whether or not the end of the focusing range (closest end or infinity end) is included in the focus detectable range calculated in step S160. If the close end or the infinity end is included, the process proceeds to step S190. In step S190, the drive instruction sending unit 103d sends a drive instruction so that the focusing lens 210b is driven in a direction opposite to the end part included in the focus detectable range.

  On the other hand, if the end portion is not included in the focus detectable range, the process proceeds to step S200, and the drive instruction sending unit is set so that the focusing lens 210b is driven in a predetermined direction (the closest end direction in the present embodiment). 103d sends a drive instruction.

According to the camera system according to the first embodiment described above, the following operational effects can be obtained.
(1) The focus control unit 103e sets the aperture diameter of the diaphragm 211 to the first aperture diameter and causes the focus detection unit 103a to detect the focus state. If the focus state cannot be detected, the focus control unit 103e increases the aperture diameter of the diaphragm 211. The second opening diameter is set to be smaller than the first opening diameter, and the end determination unit 103c is made to determine whether or not the end is included in the focus detectable range. When the focus detection possible range includes the near end, the driving instruction to drive the focusing lens 210b in the direction of the infinite end, and when the infinite end is included, the driving instruction to drive the focusing lens 210b, respectively. The sending unit 103d is controlled. Since it did in this way, the time which a focus detection requires can be shortened.

(2) The focus control unit 103e sets the aperture diameter of the diaphragm 211 to the second aperture diameter, and then causes the focus detection unit 103a to detect the focus state. When the focus state can be detected, the drive instruction sending unit 103d is controlled so that the imaging optical system 210 is in a focused state based on the focus state, and the focus state cannot be detected. Causes the edge determination unit 103c to make a determination. Since it did in this way, the frequency which performs a scanning operation | movement reduces and a quick focusing operation | movement is attained.

(3) After setting the aperture diameter of the diaphragm 211 to the second aperture diameter, the focusing control unit 103e quickly returns the aperture diameter of the diaphragm 211 to the first aperture diameter when it is no longer necessary. Since it did in this way, the appearance of the through image displayed on the display device 111 changes only for a very short time, and the user does not feel uncomfortable.

  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 automatic focus adjustment process shown in FIG. 12, when the focus control unit 103e can detect the focus after setting the second aperture diameter, the aperture diameter of the aperture 211 is returned to the first aperture diameter (step S210). Thereafter, the focusing lens 210b is driven (step S220). The driving of the diaphragm 211 and the driving of the focusing lens 210b may be performed in parallel. That is, transmission of the driving instruction for the diaphragm 211 by the focusing control unit 103e and transmission of the driving instruction for the focusing lens 210b by the driving instruction sending unit 103d are performed in succession, and the driving of the diaphragm 211 and the focusing lens 210b is performed in parallel. May be performed. By doing so, it is possible to further shorten the time required to focus. The same applies to driving of the diaphragm 211 in step S170 and driving of the focusing lens 210b in steps S190 and S200.

  Further, when the driving of the diaphragm 211 and the driving of the focusing lens 210b are performed in parallel, when the driving of the diaphragm 211 is completed (while the focusing lens 210b is driven), the focus detection unit 103a is again operated. The focus state may be detected. In this case, when the defocus amount DEF is calculated, the focus control unit 103e causes the drive instruction sending unit 103d to transmit a driving instruction for the focusing lens 210b based on the new defocus amount DEF. In general, since the accuracy of the defocus amount DEF to be calculated is higher when the aperture diameter of the diaphragm 211 is larger, the time required for final focusing can be reduced by doing so.

(Modification 2)
Instead of setting the second opening diameter to a predetermined opening diameter, an appropriate opening diameter may be obtained by calculation each time. For example, the largest aperture diameter in which the end of the focusable range is included in the focus detectable range may be set as the second aperture diameter, and such an aperture diameter may be obtained by calculation in step S130 of FIG.

(Modification 3)
In the embodiment described above, focus detection is first performed. If focus detection is impossible, the diaphragm 211 is narrowed down, and then the edge is determined after further focus detection. These operations “(A) focus detection”, “(B) narrow down to the second opening diameter”, and “(C) end determination” are in various orders. Can be combined.

  In the above-described embodiment, the processing is performed in the order of (A), (B), (A), (C), but this is performed, for example, (A), (C), (B), (A), (C). That is, when focus detection is not possible at the beginning, the end determination unit 103c determines the end before narrowing down to the second opening diameter. If the end portion is included in the focus detectable range, the focusing lens 210b is once driven in a direction opposite to the end portion and the focus detection is performed again. On the other hand, if the end portion is not included, the diaphragm 211 is narrowed down to the second opening diameter, and the process proceeds in the same flow as in the first embodiment.

  Alternatively, the processing can be performed in the order of (A), (B), and (C). That is, after the diaphragm 211 is narrowed down to the second opening diameter, the edge determination is immediately started and the scanning operation is performed. In this way, various combinations of processing flows before and after the operation of narrowing down to the second opening diameter can be considered.

(Modification 4)
In the embodiment described above, the pupil division method using focus detection pixels provided on the imaging surface is used as the focus detection method. The present invention is not limited to such a focus detection method. For example, a photoelectric conversion element for focus detection is provided separately from the image pickup element for imaging, and a part of subject light is guided to the photoelectric conversion element by a half mirror or the like, and focus detection is performed based on the output of the photoelectric conversion element. A method of performing

(Modification 5)
In the above-described embodiment, the present invention is applied to a lens-interchangeable camera system, but the present invention is not limited to such an embodiment. For example, the focus detection device to which the present invention is applied can be mounted on a lens-integrated camera, or the present invention can be applied to a so-called single-lens reflex camera.

  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, 100 ... Camera body, 103 ... Body control part, 103a ... Focus detection part, 103b ... Range calculating part, 103c ... End part determination part, 103d ... Drive instruction sending part, 103e ... Focus control part, 104 ... Image sensor 117, first body side communication unit 118, second body communication unit 200, interchangeable lens, 203 lens control unit, 210 imaging optical system, 210 b focusing lens, 217 first lens side Communication unit, 218 ... second communication unit on the lens side

Claims (5)

A focus adjusting device for adjusting a focus state of an optical system having a focusing lens and a diaphragm,
A drive unit for driving the focusing lens in the optical axis direction;
A focus detection unit that detects a focus state of the optical system by receiving a pair of light beams that have passed through different regions of the optical system and detecting a phase difference of a subject image;
Based on the focus state detected by the focus detection unit, a control unit that controls the drive unit so that the optical system is in a focused state;
A calculation unit that calculates a focus detectable range of the focus detection unit based on the aperture diameter of the diaphragm and the position of the focusing lens;
A determination unit that determines whether the focus detection possible range calculated by the calculation unit includes one of the closest end and the infinity end of the optical system;
The control unit sets the aperture diameter of the diaphragm to the first aperture diameter and causes the focus detection unit to detect the focus state. If the focus state cannot be detected, the control unit sets the aperture diameter of the aperture to the first aperture diameter. The second opening diameter is set to be smaller and the determination unit performs the determination. If the close end is included, the direction of the infinity end is included, and if the infinity end is included, the A focus detection apparatus, wherein the driving unit is controlled so that the focusing lens is driven in the direction toward the closest end. The focus detection apparatus according to claim 1,
The control unit, after setting the aperture diameter of the diaphragm to the second aperture diameter, causes the focus detection unit to detect a focus state, and when the focus state can be detected, the control unit determines the focus state based on the focus state. A focus detection apparatus that controls the drive unit so that an optical system is in a focused state and causes the determination unit to perform the determination when a focus state cannot be detected. The focus detection apparatus according to claim 2,
The control unit sets the aperture diameter of the diaphragm to the second aperture diameter, and then causes the focus detection unit to detect the focus state. If the focus state can be detected, the optical system is in focus. In parallel with the control of the drive unit to be in a state, the aperture diameter of the diaphragm is set from the second aperture diameter to the first aperture diameter. The focus detection apparatus according to claim 3,
The control unit causes the focus detection unit to detect the focus state again in response to the aperture diameter of the aperture being changed from the second aperture diameter to the first aperture diameter. An imaging apparatus comprising the focus detection apparatus according to claim 1.

Images