Camera body

Abstract

To communicate information of a communicable interchangeable lens to a camera.SOLUTION: A camera body 100 is capable of installing a camera accessory and comprises: a first contact point which outputs a first clock signal to the camera accessory; a second contact point to which a signal is input from the camera accessory synchronously with the first clock signal; a third contact point which outputs a signal to the camera accessory synchronously with the first clock signal; a fourth contact point to which, after the camera accessory is installed, a first voltage showing that the camera accessory is in a data-communicable state and a second voltage showing that the camera accessory is not in a data-communicable state are input; and a communication part which performs the data communication by sending / receiving a signal by using the second contact point and the third contact point, where the second voltage is higher than the first voltage.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a camera body. [Background technology]

[0002] In camera systems with interchangeable lenses, at least one optical element whose drive state changes, such as a focus adjustment lens, is typically located within the interchangeable lens. The camera body requires information (drive information) regarding the drive state of such driven elements for various control purposes. For example, the camera system described in Patent Document 1 is equipped with an encoder that monitors the movement of the lens transmission system. The drive amount monitor signal output by this encoder is fed back to the lens drive control CPU via a lens-side contact located in the lens mount and a corresponding body-side contact located in the body mount. Meanwhile, in the camera system described in Patent Document 1, the main CPU in the camera body is connected to the lens CPU and other components in the photographic lens via a contact separate from the contact that transmits the monitor signal. The main CPU receives information necessary for controlling the camera sequence and exposure operation from other CPUs, and sends the necessary camera sequence information to other CPUs. In other words, this contact is a contact for general-purpose communication between the main CPU and the lens CPU. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-68871 Summary of the Invention

[0004] For interchangeable lenses that can communicate with cameras, a new mechanism for communicating lens information to the camera is desired. According to a first aspect, a camera body to which a camera accessory can be attached comprises: a first contact that outputs a first clock signal to the camera accessory; a second contact to which a signal is input from the camera accessory in synchronization with the first clock signal; a third contact to which a signal is output to the camera accessory in synchronization with the first clock signal; a fourth contact to which a first voltage indicating that the camera accessory is in a state where it can perform data communication and a second voltage indicating that the camera accessory is in a state where it cannot perform data communication are input after the camera accessory is attached; and a communication unit that performs the data communication by sending and receiving signals using the second contact and the third contact, wherein the second voltage is higher than the first voltage. [Brief explanation of the drawings]

[0005] [Figure 1] 1 is a perspective view showing an interchangeable lens camera system to which the present invention is applied; [Figure 2] 1 is a cross-sectional view showing an interchangeable lens camera system to which the present invention is applied. [Figure 3] 2 is a schematic diagram showing details of the holding portions 102 and 202. FIG. [Figure 4] 10 is a timing chart showing an example of command data communication. [Figure 5] 10 is a timing chart showing an example of hotline communication. [Figure 6] FIG. 2 is a schematic diagram of a driven member (optical member). [Figure 7] 10A and 10B are diagrams showing examples of data sent and received by command data communication when the interchangeable lens 200 is initialized. [Figure 8] FIG. 4 is a diagram showing a data format of driven information. [Figure 9] FIG. 10 is a diagram showing various data transmitted and received in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0006] (First embodiment) Fig. 1 is a perspective view showing an interchangeable lens camera system to which the present invention is applied. Note that Fig. 1 shows only the devices and apparatus related to the present invention, and illustration and description of other devices and apparatus are omitted. Camera system 1 is composed of a camera body 100 and an interchangeable lens 200 that can be attached to and detached from camera body 100.

[0007] The camera body 100 is provided with a body-side mount section 101 to which an interchangeable lens 200 is detachably attached. A body-side holder (electrical connection section) 102 that holds 12 body-side connection terminals is provided in the vicinity of the body-side mount section 101 (on the inner periphery of the body-side mount section 101) in a state where it partially protrudes on the inner periphery of the body-side mount section 101.

[0008] The interchangeable lens 200 is also provided with a lens-side mount section 201 that corresponds to the body-side mount section 101 and to which the camera body 100 is detachably attached. A lens-side holder (electrical connection section) 202 that holds 12 lens-side connection terminals is provided in the vicinity of the lens-side mount section 201 (on the inner periphery of the lens-side mount section 201) in a state where it partially protrudes on the inner periphery of the lens-side mount section 201.

[0009] When the interchangeable lens 200 is attached to the camera body 100, a body-side holder 102 (described in detail later), which is provided with multiple body-side connection terminals, is electrically and physically connected to a lens-side holder 202 (described in detail later), which is provided with multiple lens-side connection terminals. These terminals are used to supply power from the camera body 100 to the interchangeable lens 200 and to send and receive signals between the camera body 100 and the interchangeable lens 200.

[0010] An image sensor 104 is provided behind a body-side mount portion 101 inside the camera body 100. Buttons 107, which serve as an input device, are provided above the camera body 100. A user uses input devices such as buttons 107 to give instructions to the camera body 100 to take pictures or to set shooting conditions.

[0011] 2 is a cross-sectional view showing an interchangeable lens camera system to which the present invention is applied. Interchangeable lens 200 is equipped with imaging optical system 210 that forms an image of a subject. Imaging optical system 210 is made up of multiple lenses 210a to 210c and iris diaphragm 211. These multiple lenses 210a to 210c include focusing lens 210b for controlling the focus position of the subject image, and blur correction lens 210c for correcting image blur of the subject image.

[0012] The interchangeable lens 200 includes a drive system (not shown) for driving the focusing lens 210b, the blur correction lens 210c, and the iris diaphragm 211. For example, the focusing lens 210b is driven by an ultrasonic motor. The blur correction lens 210c is driven by two voice coil motors, and the iris diaphragm 211 is driven by a stepping motor. That is, the focusing lens 210b, the blur correction lens 210c, and the iris diaphragm 211 are driven by a drive system provided within the interchangeable lens 200 and are driven members (optical members) whose driven state changes. Thus, in the present invention, the driven members (optical members) include not only drivable lenses included in the lenses 210a to 210c, but also members that are present on the photographing optical path and that pass or block light beams from the subject. For example, the iris diaphragm 211, which adjusts the amount of subject light passing through the imaging optical system 210, is also a driven member (optical member).

[0013] The interchangeable lens 200 also includes a lens control unit 203 that controls each unit of the interchangeable lens 200. The lens control unit 203 is composed of a microcomputer (not shown) and its peripheral circuits, etc. The lens control unit 203 is connected to a first lens side communication unit 217, a second lens side communication unit 218, a ROM 215, and a RAM 216.

[0014] The first lens side communication unit 217 and the second lens side communication unit 218 exchange data with the camera body 100 via terminals of the lens side holding unit 202 and the body side holding unit 102. The first lens side communication unit 217 and the second lens side communication unit 218 are communication interfaces on the interchangeable lens side. The lens control unit 203 uses these communication interfaces to perform various communications (hotline communication, command data communication) described below with the camera body 100 (body control unit 103 described below).

[0015] The ROM 215 is a non-volatile storage medium that stores in advance predetermined control programs and the like that are executed by the lens control unit 203. The RAM 216 is a volatile storage medium that is used by the lens control unit 203 as a storage area for various data.

[0016] A shutter 115 for controlling the exposure state of the image sensor 104 and an optical filter 116 that combines an optical low-pass filter and an infrared cut filter are provided in front of the image sensor 104. Subject light that has passed through the imaging optical system 210 is incident on the image sensor 104 via the shutter 115 and the filter 116.

[0017] Inside the camera body 100, there is provided a body control unit 103 that controls each part of the camera body 100. The body control unit 103 is made up of a microcomputer, RAM and its peripheral circuits, etc., not shown.

[0018] The body control unit 103 is connected to a first body side communication unit 117 and a second body side communication unit 118. The first body side communication unit 117 is connected to the body side holding unit 102, and can exchange data with the first lens side communication unit 217. Similarly, the second body side communication unit 118 can exchange data with the second lens side communication unit 218. In other words, the first body side communication unit 117 and the second body side communication unit 118 are each body side communication interfaces. The body control unit 103 uses these communication interfaces to perform various communications (hotline communication, command data communication) described below with the interchangeable lens 200 (lens control unit 203).

[0019] A display device 111 configured with an LCD panel or the like is disposed on the back surface of the camera body 100. The body control unit 103 displays on this display device 111 an image of the subject based on the output of the image sensor 104 (a so-called through image) and various menu screens for setting shooting conditions and the like.

[0020] (Explanation of the body side holding part 102 and the lens side holding part 202) FIG. 3 is a schematic diagram showing the details of the body-side holder 102 and the lens-side holder 202. Note that in FIG. 3, the body-side holder 102 is located to the right of the body-side mount unit 101, which is in accordance with the actual mount structure. That is, the body-side holder 102 of this embodiment is located in a position recessed from the mount surface of the body-side mount unit 101 (to the right of the body-side mount unit 101 in FIG. 3). Similarly, the lens-side holder 202 is located to the right of the lens-side mount unit 201, which indicates that the lens-side holder 202 of this embodiment is located in a position protruding from the mount surface of the lens-side mount unit 201 of the interchangeable lens 200. The camera body 100 and the interchangeable lens 200 are mounted and coupled together by bringing the mount surface of the body-side mount unit 101 and the mount surface of the lens-side mount unit 201 into contact with each other. Since the body side holder 102 and the lens side holder 202 are arranged as described above, the body side holder 102 and the lens side holder 202 are connected by mount coupling, and the electrical contacts provided on both holders are also connected. This type of mount structure is well known, so further explanation and illustration will be omitted.

[0021] 3, there are 12 contacts BP1 to BP12 on the body side holder 102. There are also 12 contacts LP1 to LP12 on the lens side holder 202, which correspond to the above 12 contacts, respectively.

[0022] Contacts BP1 and BP2 are connected to a power transmission unit 130 inside the camera body 100. The power transmission unit 130 supplies contact BP1 with operating voltage for each unit inside the interchangeable lens 200, excluding circuits that have drive systems such as actuators and consume relatively large amounts of power (such as the drive system for the focusing lens 210b). In other words, contacts BP1 and LP1 supply operating voltage for each unit inside the interchangeable lens 200, excluding the above-mentioned drive units. The voltage that can be supplied to contact BP1 ranges from a minimum voltage value to a maximum voltage value (for example, a voltage range of about 3 V), but the voltage that is normally supplied is a voltage value near the midpoint between the maximum and minimum voltage values. As a result, the current supplied from the camera body 100 to the interchangeable lens 200, when the power is on, is within a range of approximately several tens of mA to several hundreds of mA.

[0023] Contact BP2 is a ground terminal corresponding to the operating voltage applied to contact BP1. That is, contacts BP2 and LP2 are ground terminal voltages corresponding to the operating voltages. Contacts LP1 and LP2 are connected to a power receiving unit 230 in the interchangeable lens 200. The power receiving unit 230 supplies power received from the camera body 100 to each unit in the interchangeable lens 200, including the lens control unit 203.

[0024] In the following description, the signal line formed by contacts BP1 and LP1 will be referred to as signal line V33. Additionally, the signal line formed by contacts BP2 and LP2 will be referred to as signal line GND. These contacts LP1, LP2, BP1, and BP2 form power system contacts for supplying power from the camera body 100 to the interchangeable lens 200.

[0025] Contacts BP3, BP4, BP5, and BP6 are connected to the body-side first communication unit 117. Contacts LP3, LP4, LP5, and LP6 on the interchangeable lens 200 side corresponding to these contacts 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 contacts (communication system contacts). The content of communication between the body-side first communication unit 117 and the lens-side first communication unit 217 will be described in detail later.

[0026] In the following description, the signal line formed by contacts BP3 and LP3 will be referred to as signal line CLK. Similarly, the signal line formed by contacts BP4 and LP4 will be referred to as signal line BDAT, the signal line formed by contacts BP5 and LP5 will be referred to as signal line LDAT, and the signal line formed by contacts BP6 and LP6 will be referred to as signal line RDY.

[0027] 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 uses these contacts (communication system contacts) to transmit data to the body-side second communication unit 118. The content of communication between the body-side second communication unit 118 and the lens-side second communication unit 218 will be described in detail later.

[0028] In the following description, the signal line formed by contacts BP7 and LP7 will be referred to as signal line HREQ. Similarly, the signal line formed by contacts BP8 and LP8 will be referred to as signal line HANS, the signal line formed by contacts BP9 and LP9 will be referred to as signal line HCLK, and the signal line formed by contacts BP10 and LP10 will be referred to as signal line HDAT.

[0029] The contacts BP11 and BP12 are connected to a power supply circuit 140 in the camera body 100. The power supply circuit 140 supplies to the contact BP12 a drive voltage for a circuit (such as the drive system for the focusing lens 210b) that has a drive system for an actuator or the like and consumes relatively large amounts of power. That is, the drive voltage for the drive system for the focusing lens 210b or the like is supplied from the contacts BP12 and LP12. The voltage that can be supplied to the contact BP12 ranges from a minimum voltage to a maximum voltage, but all of these ranges are greater than the range of voltages that can be supplied to the contact BP1 described above (for example, the maximum voltage that can be supplied to the contact BP12 is several times the maximum voltage that can be supplied to the contact BP1). That is, the voltage that can be supplied to the contact BP12 is a voltage that is different in magnitude from the voltage that can be supplied to the contact BP1 described above. The voltage that can normally be supplied to the contact BP12 is a voltage that is approximately midway between the maximum and minimum voltages that can be supplied to the contact BP12. As a result, the current supplied from the camera body 100 to the interchangeable lens 200 has a current value of approximately 10 mA to several A when the power is on.

[0030] The contact BP11 is a ground terminal corresponding to the drive voltage applied to the contact BP12. That is, the contact BP11 and the contact LP11 are ground terminals corresponding to the drive voltage.

[0031] In the following description, the signal line formed by contacts BP11 and LP11 will be referred to as the signal line PGND. Furthermore, the signal line formed by contacts BP12 and LP12 will be referred to as the signal line BAT. These contacts LP11, LP12, BP11, and BP12 form power supply system contacts for supplying power from the camera body 100 to the interchangeable lens 200.

[0032] The following point is clear from the magnitude relationship between the voltage (current) values ​​supplied to the contacts BP12 and LP12 and the voltage (current) values ​​supplied to the contacts BP1 and LP1. That is, the difference between the maximum and minimum values ​​of the current flowing through the contacts BP11 and LP11, which serve as ground terminals for the voltages supplied to the contacts BP12 and LP12, is greater than the difference between the maximum and minimum values ​​of the current flowing through the contacts BP2 and LP2. This is because the power consumed by each drive unit having a drive system such as an actuator is greater than that consumed by electronic circuits such as the lens control unit 203 within the interchangeable lens 200, and because each drive unit does not consume power when there is no need to drive a driven member.

[0033] (Command and data communication explanation) The lens control unit 203 controls the first lens side communication unit 217 to receive control data from the first body side communication unit 117 and transmit response data to the first body side communication unit 117 in parallel at a first predetermined cycle (for example, 16 milliseconds in this embodiment) via contacts LP3 to LP6, i.e., signal lines CLK, BDAT, LDAT, and RDY. Details of communication performed between the first lens side communication unit 217 and the first body side communication unit 117 will be described below.

[0034] In this embodiment, communication performed between the lens control unit 203 and the first lens side communication unit 217 and the body control unit 103 and the first body side communication unit 117 is referred to as "command data communication." Also, a transmission path consisting of four signal lines (signal lines CLK, BDAT, LDAT, and RDY) used for command data communication is referred to as a first transmission path.

[0035] FIG. 4 is a timing chart showing an example of command data communication. At the start of command data communication (T1), the body control unit 103 and the first body-side communication unit 117 first check the signal level of the signal line RDY. The signal level of the signal line RDY indicates whether the first lens-side communication unit 217 is able to communicate. In other words, a communication availability signal indicating whether data communication is available is output from the first lens-side communication unit 217 to the signal line RDY. If communication is unavailable, the lens control unit 203 and the first lens-side communication unit 217 output an H (High) level signal from the contact LP6. In other words, the signal level of the signal line RDY is set to H level. If the signal line RDY is H level, the body control unit 103 and the first body-side communication unit 117 will not start communication until it becomes L level. Furthermore, they will not execute the next process during communication.

[0036] When the signal line RDY is at L (Low) level, the body control unit 103 and the first body-side communication unit 117 output a clock signal 401 from contact BP3. That is, the clock signal 401 is transmitted to the first lens-side 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 command packet signal 402, which is the first half of the control data, from contact BP4 in synchronization with this clock signal 401. That is, the body-side command packet signal 402 is transmitted to the first lens-side communication unit 217 via the signal line BDAT.

[0037] Furthermore, when a clock signal 401 is output to the signal line CLK, the lens control unit 203 and the first lens-side communication unit 217 output a lens-side command packet signal 403, which is the first half of the response data, from the contact LP5 in synchronization with the clock signal 401. In other words, the lens-side command packet signal 403 is transmitted to the first body-side communication unit 117 via the signal line LDAT.

[0038] The lens control unit 203 and the first lens side communication unit 217 set the signal level of the signal line RDY to H level (T2) in response to completion of transmission of the lens side command packet signal 403. The lens control unit 203 starts a first control process 404 (described below), which is a process in accordance with the contents of the received body side command packet signal 402.

[0039] When the first control process 404 is completed, the lens control unit 203 notifies the first lens side communication unit 217 of the completion of the first control process 404. In response to this notification, the first lens side communication unit 217 outputs an L-level signal from contact LP6. That is, the signal level of the signal line RDY is set to L level (T3). In response to this change in signal level, the body control unit 103 and the first body side communication unit 117 output a clock signal 405 from contact BP3. That is, the clock signal 405 is transmitted to the first lens side communication unit 217 via the signal line CLK.

[0040] The body control unit 103 and the first body-side communication unit 117 output a body-side data packet signal 406, which is the latter half of the control data, from contact BP4 in synchronization with this clock signal 405. In other words, the body-side data packet signal 406 is transmitted to the first lens-side communication unit 217 via signal line BDAT.

[0041] Furthermore, when a clock signal 405 is output to the signal line CLK, the lens control unit 203 and the lens-side first communication unit 217 output a lens data packet signal 407, which is the latter half of the response data, from the contact LP5 in synchronization with the clock signal 405. In other words, the lens-side data packet signal 407 is transmitted to the body-side first communication unit 117 via the signal line LDAT.

[0042] The lens control unit 203 and the first lens side communication unit 217 change the signal level of the signal line RDY back to H level (T4) in response to completion of transmission of the lens side data packet signal 407. The lens control unit 203 starts a second control process 408 (described below), which is a process in accordance with the content of the received body side data packet signal 406.

[0043] As described above, the lens side first communication unit 217 performs data communication with the camera body 100 using the signal line CLK over which a clock signal is output from the camera body 100, the signal line BDAT over which a data signal is output from the camera body 100 in synchronization with the clock signal, the signal line LDAT over which a data signal is output from the lens side first communication unit 217 in synchronization with the clock signal, and the signal line RDY over which a communication availability signal indicating whether or not the lens side first communication unit 217 is able to communicate data is output.

[0044] Here, the first control process 404 and the second control process 408 performed by the lens control unit 203 will be described.

[0045] For example, consider a case where the received body-side command packet signal 402 requests specific data from the interchangeable lens. As a first control process 404, the lens control unit 203 analyzes the content of the command packet signal 402 and generates the requested specific data. Furthermore, as the first control process 404, the lens control unit 203 also performs a communication error check process that uses checksum data included in the command packet signal 402 to simply check whether there are any errors in the communication of the command packet signal 402 based on the number of data bytes. 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. Note that 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 to the lens side. In this case, as a second control process 408, the lens control unit 203 performs the above-described communication error check process using the checksum data included in the body-side data packet signal 406.

[0046] Next, for example, a case will be described in which the received body-side command packet signal 402 is an instruction to drive a driven member on the lens side. For example, a case will be described in which 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 amount of drive of the focusing lens 210b. As a first control process 404, the lens control unit 203 analyzes the contents of the command packet signal 402 and generates an acknowledgement signal indicating that the contents have been understood. Furthermore, as a first control process 404, the lens control unit 203 also performs the above-mentioned communication error check process using checksum data included in the command packet signal 402. The acknowledgement signal generated in the first control process 404 is output to the body side as a lens-side data packet signal 407. Furthermore, as a second control process 408, the lens control unit 203 analyzes the contents of the body-side data packet signal 406 and performs the above-mentioned communication error check process using the checksum data included in the body-side data packet signal 406.

[0047] When the second control process 408 is completed, the lens control unit 203 notifies the first lens side communication unit 217 of the completion of the second control process 408. As a result, the lens control unit 203 causes the first lens side communication unit 217 to output an L level signal from the contact LP6. In other words, the signal level of the signal line RDY is set to L level (T5).

[0048] If the received body-side command packet signal 402 is an instruction to drive a lens-side driven member (for example, a focusing lens) as described above, the lens control unit 203 executes the following process: The lens control unit 203 causes the lens-side first communication unit 217 to set the signal level of the signal line RDY to L level, and causes the drive system of the focusing lens 210b to execute a process to drive the focusing lens 210b by the corresponding drive amount.

[0049] The communications performed from time T1 to time T5 described above constitute one command data communication. As described above, in one command data communication, the body control unit 103 and the first body side communication unit 117 transmit one body side command packet signal 402 and one body side data packet signal 406. That is, although they are transmitted in two parts for processing convenience, the body side command packet signal 402 and the body side data packet signal 406 together constitute one piece of control data.

[0050] Similarly, in one command data communication, one lens-side command packet signal 403 and one lens-side data packet signal 407 are transmitted by the lens control unit 203 and the first lens-side communication unit 217. That is, the lens-side command packet signal 403 and the lens-side data packet signal 407 together constitute one piece of response data.

[0051] As described above, the lens control unit 203 and the first lens side communication unit 217 receive control data from the first body side communication unit 117 and transmit response data to the first body side communication unit 117 in parallel. The contacts LP6 and 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.

[0052] (Hotline communication explanation) 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 contacts LP7 to LP10, i.e., signal lines HREQ, HANS, HCLK, and HDAT. Details of communication performed between the lens side second communication unit 218 and the body side second communication unit 118 will be described below.

[0053] In this 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." Also, a transmission path consisting of four signal lines (signal lines HREQ, HANS, HCLK, and HDAT) used for hotline communication is referred to as a second transmission path.

[0054] FIG. 5 is a timing chart showing an example of hotline communication. The body control unit 103 of this embodiment is configured to start hotline communication every second predetermined period (for example, 1 millisecond in this embodiment). This period is shorter than the period for command data communication. FIG. 5(a) is a diagram showing how hotline communication is repeatedly executed every predetermined period Tn. FIG. 5(b) shows an expanded view of the period Tx of one of the repeatedly executed hotline communications. The procedure of hotline communication will be described below based on the timing chart of FIG. 5(b).

[0055] At the start of hotline communication (T6), the body control unit 103 and the body-side second communication unit 118 first output an L-level signal from contact BP7. That is, the signal level of the signal line HREQ is set to L. The lens-side second communication unit 218 notifies the lens control unit 203 that this signal has been input to contact LP7. In response to this notification, the lens control unit 203 starts executing a generation process 501 for generating lens position data. The generation process 501 is a process in which the lens control unit 203 causes a focusing lens position detection unit (not shown) to detect the position of the focusing lens 210b, and generates lens position data representing the detection result.

[0056] When the lens control unit 203 completes execution of the generation process 501, the lens control unit 203 and the second lens-side communication unit 218 output an L-level signal from contact LP8 (T7). That is, the signal level of the signal line HANS is set to L. In response to this signal being input to contact BP8, the body control unit 103 and the second body-side communication unit 118 output a clock signal 502 from contact BP9. That is, the clock signal is transmitted to the second lens-side communication unit 218 via the signal line HCLK.

[0057] The lens control unit 203 and the lens-side second communication unit 218 output a lens position data signal 503 representing lens position data from the contact LP10 in synchronization with this 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.

[0058] When transmission of the lens position data signal 503 is completed, the lens control unit 203 and the lens-side second 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 H level (T8). In response to this signal being input to the contact BP8, the body-side second communication unit 118 outputs an H-level signal from the contact LP7. That is, the signal level of the signal line HREQ is set to H level (T9).

[0059] The communication performed from time T6 to time T9 described above constitutes one hotline communication. As described above, in one hotline 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. In other words, the contacts LP7 and BP7 are contacts through which asynchronous signals (signal level of the signal line HREQ / H (High) level or L (Low) level) are transmitted. The contacts LP8 and BP8 are contacts through which asynchronous signals (signal level of the signal line HANS / H (High) level or L (Low) level) are transmitted.

[0060] Command data communication and hotline communication can be performed simultaneously or partially in parallel. That is, one of the first lens side communication unit 217 and the second lens side communication unit 218 can communicate with the camera body 100 even when the other is communicating with the camera body 100.

[0061] (Explanation of driven information) The interchangeable lens 200 of this embodiment has a focusing lens 210b, a blur correction lens 210c, and an iris diaphragm 211, which are driven members (optical members) whose driven state changes. In the following explanation, information related to the positions of these three driven members (optical members) is referred to as driven information. Here, the position of the driven member refers to, for example, the position in the optical axis direction for the focusing lens 210b, the position in a plane perpendicular to the optical axis for the blur correction lens 210c, or the opening degree (position of the diaphragm blades) for the iris diaphragm 211. In addition, information related to the position of the driven member is, in other words, information related to the driven state of each driven member. The driven information of each driven member is detected by a drive information detection process executed by the lens control unit 203.

[0062] The lens control unit 203 detects the position of the focusing lens 210b by, for example, counting the number of pulses of a signal input to a drive system (such as a stepping motor) of the focusing lens 210b. Alternatively, the position of the focusing lens 210b may be detected using a well-known distance encoder or the like provided in the interchangeable lens 200. The positions of other driven members are also detected by similar well-known methods.

[0063] 6A and 6B are schematic diagrams of driven members (optical members), with FIG. 6A showing the focusing lens 210b, FIG. 6B showing the image blur correction lens 210c, and FIG. 6C showing the iris diaphragm 211. As shown in FIG. 6A, the focusing lens 210b is driven along the optical axis R. The lens control unit 203 detects the drive amount of the focusing lens 210b as drive information. The drive amount of the focusing lens 210b is represented by a 2-byte integer. This integer ranges from −65536 to +65535, and is positive when driven in the direction of arrow 41 (toward the subject) and negative when driven in the direction of arrow 42 (toward the camera body 100). The integer value representing the drive amount of the focusing lens 210b is expressed as 0, which is the position of the focusing lens 210b the previous time the drive information detection process was performed. That is, the integer value that is the driven information of the focusing lens 210b represents the position of the focusing lens 210b in the form of the amount of displacement from the previous execution.

[0064] The lens control unit 203 uses the drive amount of the focusing lens 210b when performing automatic focus adjustment. Note that the automatic focus adjustment process that the lens control unit 203 executes based on the change in the focus state of the focusing lens 210b and the drive amount of the focusing lens 210b is a well-known technique, and therefore a description thereof will be omitted.

[0065] As shown in FIG. 6(b), blur correction lens 210c is driven along horizontal axis 42 and vertical axis 43, which are perpendicular to optical axis R. Lens control unit 203 detects the drive amount of blur correction lens 210c as drive information. The drive amount of blur correction lens 210c consists of two integer values, each 1 byte in size: one represents the drive amount relative to horizontal axis 42 (horizontal drive amount) and the other represents the drive amount relative to vertical axis 43 (vertical drive amount). Each drive amount is a value in the range of −128 to +127. For the horizontal drive amount, displacement in the direction of arrow 42f is expressed as a positive value, and displacement in the direction of arrow 42b is expressed as a negative value. Similarly, for the vertical drive amount, displacement in the direction of arrow 43f is expressed as a positive value, and displacement in the direction of arrow 43b is expressed as a negative value. Like the drive information of focusing lens 210b, the drive information of blur correction lens 210c is the amount of displacement since the previous execution of the drive information detection process.

[0066] The drive amount of the blur correction lens 210c is used by the lens control unit 203 to perform automatic focus adjustment. Image blur correction using the blur correction lens 210c is performed by driving the blur correction lens 210c based on the amount of blur of the interchangeable lens 200 and changing the optical axis of the imaging optical system 210. This change in the optical axis can have an effect, for example, causing the imaging optical system 210, which was in a focused state, to become slightly out of focus. The lens control unit 203 uses the drive amount of the blur correction lens 210c to make such fine adjustments to the focused state.

[0067] FIG. 6(c) shows an iris diaphragm 211 disposed on the optical axis R. The iris diaphragm 211 has an aperture 47 formed by multiple aperture blades. The lens control unit 203 detects the size of the aperture 47 as drive information. As with other optical elements, this drive information is expressed as the amount of change in size since the previous execution of the drive information detection process. This drive information is expressed as a 2-byte integer value ranging from −65536 to +65535. This integer value represents the amount of change in the number of aperture stops, and is positive when the aperture is narrowed and negative when the aperture is widened. This integer is detected with a resolution of 1 / 12 stop. For example, if the aperture has been narrowed by 1 / 12 stop since the previous execution, the lens control unit 203 detects an integer value of +1 as the drive information of the iris diaphragm 211.

[0068] The body control unit 103 uses the drive amount of the iris diaphragm 211 to detect the state of the iris diaphragm 211. There is a time lag depending on the state of the interchangeable lens 200 between when the body control unit 103 sends an instruction to drive the iris diaphragm 211 to the lens control unit 203 and when driving of the iris diaphragm 211 is actually completed. It is difficult to accurately estimate this time lag. Therefore, the body control unit 103 generally waits a period of time that is considered to be sufficiently longer than this time lag after sending the drive instruction, so that it can reliably complete driving of the iris diaphragm 211 before executing subsequent processing. On the other hand, by obtaining the drive amount of the iris diaphragm 211, the body control unit 103 of this embodiment can detect that the iris diaphragm 211 has reliably been narrowed down to the specified size, so no extra waiting time is required.

[0069] (Explanation of initialization process) When the interchangeable lens 200 is attached while the camera body 100 is in a power-on state, power starts to be supplied to the interchangeable lens 200. At this time, the body control unit 103 and the lens control unit 203 start executing an initialization process for the interchangeable lens 200.

[0070] 7 is a diagram showing an example of data transmitted and received by command data communication when initializing the interchangeable lens 200. During the initialization process, various data necessary for controlling the interchangeable lens 200 is transmitted and received by command data communication.

[0071] During initialization processing, the lens control unit 203 transmits the characteristic data 10 shown in FIG. 7A to the body control unit 103. The characteristic data 10 is two bytes of data, with the lowest byte being a unique value indicating that the data is characteristic data. The body control unit 103 examines the lowest byte of the received data and recognizes that the data is characteristic data. In the highest byte of the characteristic data 10, each bit corresponds to a different function of the interchangeable lens 200. For example, in the example shown in FIG. 7A, the eighth bit (AF) of the characteristic data 10 corresponds to the autofocus function, and the ninth bit (VR) corresponds to the image stabilization function. If the value of each of these bits is 1, the interchangeable lens 200 is equipped with the corresponding function. Note that bits marked "N / A" in FIG. 7 indicate that no meaning is defined for that bit in this embodiment. In other words, the bit may have any value.

[0072] Having transmitted the characteristic data 10, the lens control unit 203 then transmits type data 20 shown in FIG. 7(b) to the body control unit 103. The type data 20 is two-byte data that indicates the type of drive information that the lens control unit 203 can transmit, and like the characteristic data 10, the lowest byte is a unique value indicating that it is type data. The highest byte of the type data 20 indicates the type of drive information that the interchangeable lens 200 can transmit via hotline communication. Specifically, each bit corresponds to a type of drive information that can be transmitted, and if the value of each bit is 1, the lens control unit 203 can transmit the type of drive information that corresponds to that bit.

[0073] 7(b), for example, the eighth bit (FL) of the type data 20 corresponds to the drive amount per unit time of the focusing lens 210b, the ninth bit (IR) corresponds to the drive amount per unit time of the iris diaphragm 211, and the tenth bit (VR) corresponds to the drive amount per unit time of the image blur correction lens 210c. By referencing each bit of the received type data 20, the body control unit 103 can determine what type of drive information the interchangeable lens 200 is capable of transmitting via hotline communication. The interchangeable lens 200 of this embodiment transmits type data 20 in which the FL, IR, and VR bits are all 1.

[0074] As described above, when the interchangeable lens 200 is attached to the camera body 100, the lens control unit 203 transmits type data 20 that indicates the type of drive information that the lens control unit 203 can transmit.

[0075] (Description of the driven information detection process) After the initialization process is complete, the body control unit 103 periodically requests the lens control unit 203 to start hotline communication. When the lens control unit 203 receives a request to start hotline communication from the camera body 100, it executes a process to detect driven information. Here, the request to start hotline communication is a change in the signal level of the specific signal line (signal line HREQ) mentioned above. The process to detect driven information is a process to detect driven information to be sent to the body control unit 103 from each optical member (driven member).

[0076] (Description of the driven information transmission process) After executing the process of detecting the driven information, the lens control unit 203 then executes a process of transmitting the driven information. In the process of transmitting the driven information, each piece of driven information detected by the process of detecting the driven information is transmitted by the lens control unit 203 to the body control unit 103.

[0077] Fig. 8 is a diagram showing the data format of the driven information. Figs. 8(a) to 8(c) respectively show FL data 51 indicating the drive amount of focusing lens 210b, IR data 52 indicating the drive amount of iris diaphragm 211, and VR data 53 indicating the drive amount of blur correction lens 210c. As described above, the drive amount of focusing lens 210b and the drive amount of iris diaphragm 211 are each detected as a 2-byte integer value, so as shown in Figs. 8(a) and 8(b), FL data 51 and IR data 52 are 2 bytes in size.

[0078] The drive amount of blur correction lens 210c is detected as a 1-byte integer value for each of the left-right drive amount and the up-down drive amount. Correspondingly, as shown in Figure 8(c), VR data 53 is 2-byte data in which the lower byte represents the left-right drive amount VRX and the upper byte represents the up-down drive amount VRY.

[0079] The lens control unit 203 concatenates these pieces of data shown in Figures 8(a) to (c) in a predetermined order to create transmission data to be sent to the body control unit 103 via hotline communication. Figure 8(d) shows transmission data 54 created in this way. The lens control unit 203 concatenates, starting from the least significant byte, the drive amount of the focusing lens 210b (FL data 51), the drive amount of the iris diaphragm 211 (IR data 52), and the drive amount of the blur correction lens 210c (VR data 53).

[0080] If the interchangeable lens 200 does not have any of the driven members (optical members) among the focusing lens 210b, the image blur correction lens 210c, and the iris diaphragm 211, then naturally the drive information of that driven member is not included in the transmission data created by the lens control unit 203. Furthermore, if the interchangeable lens 200 further has another driven member, the drive information of that driven member is further added to the transmission data created by the lens control unit 203.

[0081] As described above, the lens control unit 203 repeatedly transmits drive information for each driven member of the interchangeable lens 200 to the camera body 100 via the first transmission unit 301 in accordance with the above-mentioned clock signal generated in the camera body 100.

[0082] The camera system according to the first embodiment described above provides the following advantageous effects. (1) The interchangeable lens 200 includes a lens-side mount unit 201 to which the camera body 100 can be attached, an imaging optical system 210 including multiple driven members whose drive states change, a first lens-side communication unit 217, and a second lens-side communication unit 218. The second lens-side communication unit 218 transmits multiple pieces of drive information relating to the positions of the multiple driven members to the camera body 100 via the second transmission path in response to a clock signal output from the camera body 100. The first lens-side communication unit 217 transmits type data 20 indicating the type of drive information that can be transmitted by the second lens-side communication unit 218 via the first transmission path. This allows the camera body 100 to grasp the type of drive information transmitted from the interchangeable lens 200. In other words, the interchangeable lens 200 can notify the camera body 100 in advance of the type of drive information that it will transmit in the future.

[0083] (2) The lens control unit 203 transmits the type data 20 when the interchangeable lens 200 is attached to the camera body 100. This allows the body control unit 103 to quickly start acquiring driven information after the interchangeable lens 200 is attached.

[0084] (3) The lens control unit 203 transmits the driven information via a second transmission path that is specialized for communication of the driven information. This prevents a decrease in the responsiveness of communication of the driven information due to communication congestion on the first transmission path, etc.

[0085] (4) The body control unit 103 requests the start of hotline communication by changing the signal level of a specific signal line, rather than sending data indicating a communication request to the lens control unit 203. This prevents unnecessary communication from occurring due to a request to send driven information.

[0086] (5) The lens control unit 203 transmits multiple types of drive information via hotline communication. This allows the transmitted data to be changed appropriately even if the number of types of drive information increases, eliminating the need for additional signal lines, encoders, etc., as in conventional examples.

[0087] (Second embodiment) A camera system according to a second embodiment of the present invention has a similar configuration to the camera system according to the first embodiment, but differs from the first embodiment in the details of the initialization process of the interchangeable lens 200. The following describes the camera system according to the second embodiment, focusing on the differences from the first embodiment. In the following description, the same components as those in the first embodiment are designated by the same reference numerals as those in the first embodiment, and their description will be omitted.

[0088] 9A and 9B are diagrams showing various types of data transmitted and received in the second embodiment. Fig. 9A shows designation data 30 transmitted from the body control unit 103 to the lens control unit 203 during initialization processing. Upon receiving type data 20, the body control unit 103 executes a determination process to determine whether or not the body control unit 103 needs the type of drive information that can be transmitted by the interchangeable lens 200. Then, the body control unit 103 transmits designation data 30 to the lens control unit 203, specifying the type of drive information determined to be necessary in the determination process.

[0089] In this embodiment, the designation data 30 is two-byte data, and like the characteristic data 10 and type data 20, the lowest byte is a unique value indicating that it is designation data. The highest byte of the designation data 30 indicates the type of drive information to be transmitted from the interchangeable lens 200 via hotline communication. Specifically, like the type data 20, each bit corresponds to a type of drive information, and if each bit is 1, the body control unit 103 is requesting the lens control unit 203 for the type of drive information corresponding to that bit.

[0090] In FIG. 9(a), the eighth bit (FL) of the specification data 30 corresponds to the drive amount per unit time of the focusing lens 210b, the ninth bit (IR) corresponds to the drive amount per unit time of the iris diaphragm 211, and the tenth bit (VR) corresponds to the drive amount per unit time of the image blur correction lens 210c. For example, if the user sets the camera body 100 to autofocus mode, the body control unit 103 needs to know the drive amount of the focusing lens 210b to perform automatic focus adjustment. Therefore, the body control unit 103 determines in the above-mentioned determination process that the drive amount of the focusing lens 210b is necessary. Then, it transmits specification data 30 in which the eighth bit is 1 to the interchangeable lens 200. On the other hand, if the camera body 100 is set to manual focus mode, the body control unit 103 does not perform automatic focus adjustment and therefore does not need to drive the focusing lens 210b. Therefore, the body control unit 103 transmits specification data 30 in which the eighth bit is 0 to the interchangeable lens 200.

[0091] In the determination process, the body control unit 103 determines that drive information is not necessary in the following cases: For example, suppose the interchangeable lens 200 is a new interchangeable lens manufactured after the camera body 100 and is capable of transmitting a new type of drive information that the camera body 100 did not anticipate. In this case, the camera body 100 does not know how to use that type of drive information, so it determines that that type of drive information is unnecessary. Also, if the camera body 100 is an inexpensive camera body with only limited functions, it may not be equipped with advanced control functions that use a specific type of drive information. In such a case, that type of drive information is not necessary either.

[0092] When the lens control unit 203 receives the designation data 30, it repeatedly transmits the type of drive condition information specified by the designation data 30 to the body control unit 103. However, the lens control unit 203 may not be able to correctly receive the designation data 30 for various reasons, such as the signal line being affected by electrical noise. In this way, if the designation data 30 is not received during the initialization process, the lens control unit 203 of this embodiment transmits all transmittable types of drive condition information to the body control unit 103 in hotline communication after the initialization process. Note that "if the designation data 30 is not received during the initialization process" naturally includes not only cases where the body control unit 103 transmitted the designation data 30 but was unable to receive it, but also cases where the body control unit 103 did not transmit the designation data 30.

[0093] When the body control unit 103 transmits designation data 30 excluding some of the drive condition information (for example, drive condition information for the focusing lens 210b), and the lens control unit 203 correctly receives the designation data 30, the lens control unit 203 transmits, for example, transmission data 55 shown in FIG. 9B via hotline communication. Unlike the transmission data 54 shown in FIG. 8D, the transmission data 55 does not include FL data 51. On the other hand, if the lens control unit 203 does not correctly receive the designation data 30, the lens control unit 203 transmits transmission data 54 (FIG. 8D) including all of the drive condition information, even though the body control unit 103 did not request the drive condition information. In other words, the lens control unit 203 transmits transmission data 54 regardless of the designation data 30 from the body control unit 103. After receiving this transmission data 54, the body control unit 103 recognizes from the data length of the transmission data 54 that FL data 51 is present at the beginning, and simply ignores the FL data 51.

[0094] The camera system according to the second embodiment described above provides the following advantageous effects. (1) The lens control unit 203 receives designation data 30 specifying the type of drive information from the camera body 100 via the first transmission path. If the lens control unit 203 is not successful in receiving the designation data 30, it transmits all types of drive information that it can transmit. In other words, the lens control unit 203 transmits transmission data 54 regardless of the designation data 30 from the body control unit 103. In this way, the camera body 100 can receive drive information even if it fails to transmit the designation data 30 specifying the drive information.

[0095] The following modifications are also within the scope of the present invention, and one or more of the modifications may be combined with the above-described embodiment.

[0096] (Variation 1) Two or more types of drive information may exist for one driven member (optical member). For example, in the first embodiment, VR data 53 indicating the drive amount of blur correction lens 210c is composed of a horizontal drive amount VRX and a vertical drive amount VRY, but these two drive amounts may be treated as separate pieces of drive information. Also, two or more pieces of drive information that are completely different in type or usage may exist for one driven member (optical member). For example, in the first embodiment, in addition to FL data 51 indicating the drive amount of focusing lens 210b, data indicating the drive speed of focusing lens 210b may also be made available.

[0097] (Variation 2) The initialization process may be performed at any timing. For example, it may be performed when the interchangeable lens 200 is attached even if the camera body 100 is in a power-off state, or it may be performed if the interchangeable lens 200 is attached when the camera body 100 is powered on.

[0098] (Variation 3) The representation format of the driven information is not limited to the format described in the first embodiment. For example, the drive amount of each optical element may be represented by an integer value representing the absolute position of the optical element, or may be represented by a representation format other than a 2-byte integer value (for example, floating point). The same applies to the characteristic data 10, type data 20, and specification data 30.

[0099] (Variation 4) The manner in which each piece of driven information is used may differ from that described in the first embodiment. For example, the amount of drive of the focusing lens 210b may be used in processing other than automatic focus adjustment.

[0100] (Variation 5) The interchangeable lens 200 may be provided with other driven members in addition to the focusing lens 210b, the image blur correction lens 210c, and the iris diaphragm 211. For example, like the focusing lens 210b, the interchangeable lens 200 may be provided with a zoom lens as a member that is movable in the optical axis direction of the interchangeable lens (imaging optical system 210), and a mechanism (power zoom mechanism) that electrically drives the zoom lens may be provided in the interchangeable lens 200.

[0101] (Variation 6) When the lens control unit 203 transmits transmission data via hotline communication regardless of the specified data 30 from the body control unit 103, it does not have to be configured to transmit the same combination of data types every time. For example, the combination of data types to be transmitted may be changed for each transmission timing. As a specific example, the configuration may be such that "position information of the focusing lens 210b" is transmitted at the first transmission timing, "position information of the focusing lens 210b, position information of the image blur correction lens 210c, and blade position information of the iris diaphragm 211" such as the transmission data 54 described above is transmitted at the second transmission timing, and "position information of the image blur correction lens 210c and blade position information of the iris diaphragm 211" such as the transmission data 55 described above is transmitted at the third transmission timing, and transmission is repeated in this order thereafter.

[0102] The present invention is not limited to the above-described embodiments, and other forms that are conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention, as long as the features of the present invention are not impaired.

[0103] The disclosures of the following priority applications are incorporated herein by reference: Japanese Patent Application No. 2011-198422 (filed September 12, 2011)

Claims

[Claim 1] A camera body to which a camera accessory can be attached, a first contact for outputting a first clock signal to the camera accessory; a second contact to which a signal is input from the camera accessory in synchronization with the first clock signal; a third contact for outputting a signal to the camera accessory in synchronization with the first clock signal; a fourth contact to which a first voltage indicating that the camera accessory is in a state where it can perform data communication and a second voltage indicating that the camera accessory is in a state where it cannot perform data communication are input after the camera accessory is attached; a communication unit that performs the data communication by transmitting and receiving signals using the second contact and the third contact; Equipped with The second voltage is higher than the first voltage.

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