Camera system

Abstract

To solve the problem in which: camera accessories include a master lens capable of forming a subject image and an intermediate accessory mountable between the master lens and a camera body; in the prior art, the number of terminals needs to be changed between the master lens and the intermediate accessory, so as to distinguish the master lens and the intermediate accessory from each other when seen from the camera body.SOLUTION: A camera system has at least one accessory and a camera body communicable with the accessory, and comprises: the camera body including a body-side mount; and the accessory including an accessory-side mount removably mounted on the body-side mount, and a receiving unit receiving an instruction signal transmitted from the camera body. The instruction signal includes identification information and an instruction from the camera body. The identification information is information for identifying the accessory that is mounted on the body-side mount and communicable with the camera body.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Camera accessories include a master lens that can form an image of a subject, and an intermediate accessory that can be attached between the master lens and the camera body (see Patent Document 1). In conventional technology, in order to distinguish between the master lens and the intermediate accessory from the camera body, it was necessary to use different numbers of terminals for the master lens and the intermediate accessory. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 63-38926 Summary of the Invention

[0004] A camera system having at least one accessory and a camera body capable of communicating with the accessory, the camera body having a body-side mount, an accessory-side mount detachable from the body-side mount, and an accessory having a receiving unit that receives an instruction signal transmitted from the camera body, the instruction signal including identification information and an instruction from the camera body, and the identification information being information that identifies the accessory that is attached to the body-side mount and capable of communicating with the camera body. [Brief explanation of the drawings]

[0005] [Figure 1] FIG. 1 is a perspective view illustrating a camera system. [Figure 2] FIG. 1 is a block diagram illustrating the configuration of a main part of a camera system including a teleconverter. [Figure 3] FIG. 2 is a circuit diagram showing a schematic diagram of electrical connections between the camera body, the teleconverter, and the interchangeable lens. [Figure 4] 10A and 10B are diagrams illustrating examples of the timing of command data communication performed between a body-side communication unit and a lens-side communication unit. [Figure 5] 10A and 10B are diagrams illustrating examples of the timing of hotline communication performed between a body-side communication unit and a lens-side communication unit. [Figure 6] FIG. 6(a) is a diagram illustrating the structure of a command packet, and FIG. 6(b) is a diagram illustrating the structure of a data packet. [Figure 7] 10 is a diagram illustrating the flow of processing in device ID allocation command data communication and normal command data communication. FIG. [Figure 8] 10 is a flowchart illustrating the flow of processing executed in the body-side control unit, the control / communication unit, and the lens-side control unit during device ID allocation command data communication. [Figure 9] 10 is a flowchart illustrating the flow of normal command data communication executed in the body-side control unit, the control / communication unit, and the lens-side control unit during normal command data communication. DETAILED DESCRIPTION OF THE INVENTION

[0006] Hereinafter, an embodiment of the invention will be described with reference to the drawings. Fig. 1 is a perspective view of a camera system 1 according to an embodiment of the invention before any camera accessories are attached to a camera body 2. Fig. 2 is a block diagram illustrating the configuration of the main parts of the camera system 1. The camera accessories of this embodiment include an interchangeable lens 3 as a master lens and a teleconverter 4 as an intermediate accessory. The master lens of this embodiment refers to a device that is attached to the camera body 2 and can form a subject image. The master lens of this embodiment refers to a device that does not have other camera accessories attached to its subject side in a state where it can communicate with them. The intermediate accessory of this embodiment refers to a device that can be attached to its subject side in a state where other devices can communicate with it, and is also called a non-master lens. A non-master lens is used in combination with a master lens. The camera body 2 and camera accessories, and the camera accessories themselves, are coupled together using a bayonet structure between the body-side mount and lens-side mount. Therefore, the body-side mount 210 of the camera body 2 and the front mount 413 located on the lens side of the teleconverter 4 have approximately the same shape, and the lens-side mount 310 of the interchangeable lens 3 and the rear mount 412 located on the body side of the teleconverter 4 have approximately the same shape. Therefore, the interchangeable lens 3 can be used by attaching it directly to the camera body 2 without using the teleconverter 4, or by attaching it indirectly to the camera body 2 via the teleconverter 4. When the camera body 2 and camera accessories, or the camera accessories themselves, are coupled, the terminals on each mount come into physical contact and are electrically connected.

[0007] <Interchangeable lenses> The interchangeable lens 3 has a lens mount 310, a lens control unit 330, a lens communication unit 340, a lens storage unit 350, a lens power supply circuit 352, an imaging optical system 360, a lens driver 370, and an aperture driver 380.

[0008] The annular lens mount 310 is provided with a lens terminal holder 320. The lens terminal holder 320 arranges multiple lens terminals in an arc shape centered on the optical axis. The multiple lens terminals include, for example, an attachment detection terminal that transmits a signal to the camera body 2 indicating that the interchangeable lens 3 has been attached to the camera body 2, a communication terminal used for communication between the interchangeable lens 3 and the camera body 2, a power supply terminal through which power is supplied from the camera body 2 to the interchangeable lens 3, and a ground terminal.

[0009] When the interchangeable lens 3 is attached to the camera body 2 via the teleconverter 4, the signals and power transmitted by each terminal are transmitted from the interchangeable lens 3 to the camera body 2 via the teleconverter 4. When the interchangeable lens 3 is attached directly to the camera body 2, the signals and power are transmitted directly from the interchangeable lens 3 to the camera body 2.

[0010] The lens side control unit 330 is composed of a microcomputer and its peripheral circuits, etc. The lens side control unit 330 executes a control program stored in the lens side memory unit 350 to control each unit of the interchangeable lens 3. In addition, in response to a request from the camera body 2, the lens side control unit 330 reads data stored in the lens side memory unit 350 and transmits the data from the lens side communication unit 340 to the camera body 2 via the teleconverter 4 or directly. The lens side control unit 330 is connected to the lens side communication unit 340, lens side memory unit 350, lens driver 370, and aperture driver 380.

[0011] Based on instructions from the body-side communication unit 240, the lens-side communication unit 340 performs predetermined communication with the body-side communication unit 240 either directly or via the teleconverter 4. The lens-side communication unit 340 is connected to the lens-side control unit 330 and the communication terminal described above. Through communication between the body-side communication unit 240 and the lens-side communication unit 340, instructions to move the lens 361 (described below) and requests to send information such as data stored in the lens-side memory unit 350 are sent from the camera body 2 via the teleconverter 4 or directly to the interchangeable lens 3. Meanwhile, based on instructions from the body-side communication unit 240, information indicating the state inside the interchangeable lens 3, such as the position of the lens 361 after movement, and data read from the lens-side memory unit 350 are sent from the interchangeable lens 3 via the teleconverter 4 or directly to the camera body 2.

[0012] The lens-side storage unit 350 is configured with a non-volatile storage medium. The lens-side control unit 330 controls the recording and reading of data in the lens-side storage unit 350. In addition to storing control programs and the like executed by the lens-side control unit 330, the lens-side storage unit 350 can also store data indicating the model name of the interchangeable lens 3 (also referred to as model name information), data indicating the optical characteristics of the imaging optical system 360, and data indicating a device ID. The device ID is an identifier used to identify a camera accessory attached to the camera body 2, and is data composed of codes and the like used to specify a communication partner from among the attached camera accessories. The device ID is transmitted from the camera body 2 each time the interchangeable lens 3 is attached to the camera body 2 (or attachment is detected). The lens-side storage unit 350 is connected to the lens-side control unit 330.

[0013] The power supply circuit 352 distributes power supplied from the camera body 2 to the interchangeable lens 3 via the power supply terminal to each section within the interchangeable lens 3. The power supply circuit 352 is connected to the power supply terminal described above.

[0014] The imaging optical system 360 forms a subject image on the imaging plane either directly or via the teleconverter 4. The optical axis O of the imaging optical system 360 substantially coincides with the center positions of the lens mount 310, the front mount 413 of the teleconverter 4, the rear mount 412 of the teleconverter 4, the body mount 210, and the imaging plane. The imaging optical system 360 is composed of, for example, multiple lenses 361 including a focusing lens, a zoom lens, etc., and an aperture 362. At least some of the multiple lenses 361 are configured to be movable along the optical axis O by a lens driver 370 or manually. The position of each lens along the optical axis O is configured to be detectable by an encoder or the like of the lens driver 370.

[0015] The diaphragm 362 adjusts the amount of light incident on the image sensor 260. The diaphragm 362 is configured so that the aperture diameter (aperture value) can be changed by the diaphragm driving unit 380 or by manual operation. The aperture diameter of the diaphragm 362 is configured so that it can be detected by an encoder of the diaphragm driving unit 380 or the like.

[0016] The lens driving unit 370 is configured with, for example, a motor and a lens driving mechanism. Based on instructions from the lens side control unit 330, the lens driving unit 370 moves the focusing lens included in the lens 361 along the direction of the optical axis O. The lens driving unit 370 is connected to the lens side control unit 330. The diaphragm driving unit 380 is made up of a motor and a diaphragm driving mechanism. The diaphragm driving unit 380 changes the opening diameter of the diaphragm 362 based on instructions from the lens side control unit 330. The diaphragm driving unit 380 is connected to the lens side control unit 330.

[0017] <Teleconverter 4> The teleconverter 4 has a rear mount 412 that faces the body-side mount 210 when attached to the camera body 2, a front mount 413 that faces the lens-side mount 310 when the interchangeable lens 3 is attached, an accessory-side control / communication unit 435, an accessory-side memory unit 437, a switch 450, an accessory-side power supply circuit 452, and a lens 460.

[0018] The rear mount 412 is provided with a rear terminal holding portion 422 in which multiple terminals are arranged in an arc shape centered on the optical axis. The front mount 413 is provided with a front terminal holding portion 423 in which multiple terminals are arranged in an arc shape centered on the optical axis. The multiple terminals arranged in the rear terminal holding portion 422 and the front terminal holding portion 423 include an attachment detection terminal that transmits a signal indicating that the camera accessory is attached, a communication terminal used for communication between the camera accessory and the camera body 2, a power supply terminal through which power is supplied from the camera body 2 to the camera accessory, and a ground terminal. Here, the terminals included in the rear terminal holding portion 422, which is arranged on the rear side (camera body 2 side) of the intermediate accessory, are the same as the terminals included in the lens-side terminal holding portion 320 of the lens-side mount 310. Furthermore, the terminals included in the front terminal holding portion 423, which is arranged on the front side (subject side) of the intermediate accessory, are the same as the terminals included in the body-side terminal holding portion 220 arranged on the body-side mount 210.

[0019] The accessory-side control / communication unit 435 is composed of a microcomputer, a memory unit, and its peripheral circuits. The accessory-side control / communication unit 435 executes a control program stored in the accessory-side memory unit 437 to control the opening and closing of the switch 450. When the switch 450 is closed, power supplied from the camera body 2 to the power supply circuit 452 is supplied to the interchangeable lens 3, and when the switch 450 is opened, the power supply to the interchangeable lens 3 is cut off. The accessory-side control / communication unit 435 also performs predetermined communication with the body-side communication unit 240. Furthermore, in response to a request from the camera body 2, the accessory-side control / communication unit 435 reads data stored in the accessory-side memory unit 437 and transmits it to the camera body 2. The accessory-side control / communication unit 435 also controls operations and detection within the teleconverter 4 in response to instructions from the camera body 2. The accessory-side control / communication unit 435 is connected to the communication terminal and switch 450 described above.

[0020] The accessory-side storage unit 437 has data recording and reading controlled by the accessory-side control / communication unit 435. The accessory-side storage unit 437 stores control programs and the like executed by the accessory-side control / communication unit 435, and can also store data indicating the model name of the teleconverter 4 (also referred to as model name information), data indicating a device ID, and the like. The accessory-side storage unit 437 is connected to the accessory-side control / communication unit 435.

[0021] The switch 450 is configured by a semiconductor switch element using, for example, a FET (field effect transistor). The on / off of the switch 450 is controlled by a control signal input from the accessory-side control / communication unit 435 to the switch 450. Switch-off means that the contact is open, and switch-on means that the contact is closed. The switch 450 is off, for example, when a high-level (hereinafter referred to as "H level") control signal is not input from the accessory-side control / communication unit 435 (i.e., when a low-level (hereinafter referred to as "L level") control signal is input), and is on when an H-level control signal is input from the accessory-side control / communication unit 435. The switch 450 is connected to the power supply circuit 452, the power supply terminal of the second lens-side terminal, and the accessory-side control / communication unit 435.

[0022] The power supply circuit 452 distributes the power supplied to the teleconverter 4 via the power supply terminal and ground terminal on the body side to each section within the teleconverter 4 or to the interchangeable lens 3. The power supply circuit 452 is connected to the power supply terminal and the switch 450.

[0023] Lens 460 is a teleconverter lens that converts the focal length of lens 361 by, for example, 1.4 times. When teleconverter 4 is attached to interchangeable lens 3, the focal length of interchangeable lens 3 becomes 1.4 times greater than when teleconverter 4 is not attached.

[0024] <Camera body> The camera body 2 has a body mount 210 , a body control unit 230 , a body communication unit 240 , a power supply unit 250 , an image sensor 260 , a signal processing unit 270 , an operation member 280 , and a display unit 290 .

[0025] The annular body-side mount 210 is provided with a body-side terminal holder 220. The body-side terminal holder 220 has multiple body-side terminals. The multiple body-side terminals include, for example, an attachment detection terminal that transmits a signal indicating that an interchangeable lens 3 has been attached to the camera body 2, either directly or via the teleconverter 4, to the camera body 2, a communication terminal used for communication between the camera body 2 and the teleconverter 4 or interchangeable lens 3, a power supply terminal through which power is supplied from the camera body 2 to the teleconverter 4 or interchangeable lens 3, and a ground terminal.

[0026] The body side control unit 230 is composed of a microcomputer and its peripheral circuits, etc. The body side control unit 230 executes a control program stored in the storage unit 235 to control each unit within the camera body 2. The body side control unit 230 is connected to the body side communication unit 240, power supply unit 250, image sensor 260, signal processing unit 270, operation member 280, display unit 290, and the above-mentioned attachment detection terminal.

[0027] The body-side control unit 230 includes a storage unit 235. The body-side control unit 230 controls the recording and reading of data in the storage unit 235. In addition to storing control programs and the like executed by the body-side control unit 230, the storage unit 235 can also store model name information for camera accessories and data indicating the optical characteristics of the camera accessories. Furthermore, when a camera accessory is attached, the body-side control unit 230 assigns a device ID as described below, and retains and temporarily stores the device ID sent to the camera accessory. The body-side control unit 230 erases the retained device ID information when the power is turned off or the camera accessory is removed.

[0028] The body side communication unit 240 performs the above-mentioned communication with the lens side communication unit 340 or the accessory side control / communication unit 435. The body side communication unit 240 is connected to the body side control unit 230 and the above-mentioned communication terminal. The power supply unit 250 converts the voltage of a battery (not shown) into a voltage used by each part of the camera system 1, and supplies it to each part of the camera body 2, the interchangeable lens 3, and the teleconverter 4. The power supply unit 250 can switch power supply on and off for each power supply destination in response to instructions from the body-side control unit 230. The power supply unit 250 is connected to the body-side control unit 230 and the above-mentioned power supply terminal.

[0029] The image sensor 260 is a solid-state image sensor such as a CMOS image sensor or a CCD image sensor. The image sensor 260 captures an image of a subject on an imaging surface and outputs an imaging signal in response to a control signal from the body-side control unit 230. The image sensor 260 is connected to the body-side control unit 230 and the signal processing unit 270.

[0030] The image sensor 260 has pixels for generating an image (referred to as imaging pixels) and pixels for focus detection (referred to as focus detection pixels). Signals generated by the imaging pixels (hereinafter referred to as imaging pixel signals) are used to generate image data by a signal processing unit 270 (described later). Furthermore, signals generated by the focus detection pixels (hereinafter referred to as focus detection pixel signals) are used by the signal processing unit 270 (described later) for focus detection processing that detects the imaging state of an image formed by the interchangeable lens 3, in other words, the focus position.

[0031] The signal processing unit 270 generates image data by performing predetermined image processing on the imaging pixel signals output from the image sensor 260. The generated image data is recorded in a predetermined file format on a storage medium (not shown), or is used to display an image on the display unit 290. The signal processing unit 270 is connected to the body-side control unit 230, the image sensor 260, and the display unit 290.

[0032] Furthermore, the signal processing unit 270 detects the focal position of the interchangeable lens 3 and calculates the defocus amount using the focus detection pixel signals output from the image sensor 260. Based on the calculated defocus amount, the signal processing unit 270 calculates the amount of movement of the focusing lens to the in-focus position.

[0033] An operation member 280 including a release button, operation switches, etc. is provided on the exterior surface of the camera body 2. The user issues instructions for shooting, instructions for setting shooting conditions, etc. by operating the operation member 280. The operation member 280 sends an operation signal to the body-side control unit 230 in response to the user's operation. The display unit 290 is configured by, for example, a liquid crystal display panel. The display unit 290 displays images based on image data processed by the signal processing unit 270, operation menu screens, etc., in response to instructions from the body-side control unit 230. The display unit 290 is connected to the body-side control unit 230 and the signal processing unit 270.

[0034] <Terminal details> 3 is a circuit diagram that schematically shows the electrical connections between the camera body 2, the teleconverter 4, and the interchangeable lens 3. In FIG. 3, arrows indicate the flow of signals. The body-side terminal holding section 220 of the body-side mount 210 has the following body-side terminals: LDET(B) terminal, VBAT(B) terminal, PGND(B) terminal, V33(B) terminal, GND(B) terminal, RDY(B) terminal, DATAB(B) terminal, CLK(B) terminal, DATAL(B) terminal, HCLK(B) terminal, and HDATA(B) terminal. These 11 body-side terminals are collectively referred to as the body-side terminal group. The terminals of the body-side terminal group are arranged in the order shown in FIG. 3 on an arc centered on the central axis of the body-side mount section 210.

[0035] The lens-side terminal holding portion 320 of the lens-side mount 310 has an LDET(L) terminal, a VBAT(L) terminal, a PGND(L) terminal, a V33(L) terminal, a GND(L) terminal, a RDY(L) terminal, a DATAB(L) terminal, a CLK(L) terminal, a DATAL(L) terminal, an HCLK(L) terminal, and an HDATA(L) terminal. These 11 lens-side terminals are collectively referred to as the lens-side terminal group. The terminals of the lens-side terminal group are arranged in the lens-side terminal holding portion 320 in the order shown in FIG. 3, forming an arc centered on the optical axis.

[0036] In the teleconverter 4, the second terminal group included in the front terminal holding portion 423 is the same as the body side terminal group, and the first terminal group included in the rear terminal holding portion 422 is the same as the lens side terminal group. In Figure 3, the labels for the terminals of the rear terminal holding portion 422 and the front terminal holding portion 423 are omitted.

[0037] Furthermore, the accessory side control / communication unit 435 is connected in parallel between the RDY(B) terminal of the camera body 2 and the RDY(L) terminal of the interchangeable lens 3, between the DATAB(B) terminal of the camera body 2 and the DATAB(L) terminal of the interchangeable lens 3, between the CLK(B) terminal of the camera body 2 and the CLK(L) terminal of the interchangeable lens 3, and between the DATAL(B) terminal of the camera body 2 and the DATAL(L) terminal of the interchangeable lens 3.

[0038] The RDY(B) terminal, DATAB(B) terminal, CLK(B) terminal, DATAL(B) terminal, HCLK(B) terminal, HDATA(B) terminal, RDY(L) terminal, DATAB(L) terminal, CLK(L) terminal, DATAL(L) terminal, HCLK(L) terminal, and HDATA(L) terminal are the communication terminals described above. Of the communication terminals, the RDY(B) terminal, DATAB(B) terminal, CLK(B) terminal, and DATAL(B) terminal are used for command data communication, which will be described later. Furthermore, of the communication terminals, the HCLK(B) terminal and HDATA(B) terminal are used for hotline communication, which will be described later. In this embodiment, two communication systems are provided: command data communication and hotline communication. The command data communication and hotline communication are different and independent communication systems. The RDY(B) terminal, DATAB(B) terminal, CLK(B) terminal, DATAL(B) terminal, HCLK(B) terminal, and HDATA(B) terminal are each connected to the body side control unit 230 via the body side communication unit 240. The RDY(L) terminal, DATAB(L) terminal, CLK(L) terminal, DATAL(L) terminal, HCLK(L) terminal, and HDATA(L) terminal are each connected to the lens side control unit 220 via the lens side communication unit 340.

[0039] The RDY(B) terminal is an input terminal to which a signal from the RDY(L) terminal is input. A signal indicating whether or not the interchangeable lens 3 is capable of command data communication (hereinafter referred to as the RDYL signal) is input to the RDY(B) terminal from the RDY(L) terminal of the interchangeable lens 3 via the teleconverter 4. A signal indicating whether or not the teleconverter 4 is capable of command data communication (hereinafter referred to as the RDYA signal) is input to the RDY(B) terminal from the teleconverter 4. When command data communication is possible, the lens-side control unit 330 changes the potential of the RDYL signal from L level to L level, once via H level. When command data communication is possible, the accessory-side control / communication unit 435 changes the potential of the RDYA signal from L level to L level, once via H level. Upon receiving the RDYL signal or RDYA signal, the RDY(B) terminal transmits the RDYB signal to the body-side control unit 230 via the body-side communication unit 240. When the body side control unit 230 detects that the potential of the RDYB signal has changed from L level to H level to L level, it determines whether the camera accessory specified by the device ID is capable of command data communication. The lens-side control unit 330 can switch the output of the RDY(L) terminal of the interchangeable lens 3 to a high-impedance state. Furthermore, the accessory-side control / communication unit 435 can switch the output of the RDY(L) terminal of the teleconverter 4 to a high-impedance state. The high-impedance state refers to a state in which the connection with the body-side communication unit 240 is essentially cut off. When the accessory-side control / communication unit 435 cuts off the connection with the body-side communication unit 240, the lens-side communication unit 340 becomes connected to the body-side communication unit 240. Furthermore, when the lens-side communication unit 340 cuts off the connection with the body-side communication unit 240, the accessory-side control / communication unit 435 becomes connected to the body-side communication unit 240. When the accessory-side control / communication unit 435 is connected to the body-side communication unit 240, an RDYA signal from the teleconverter 4 is transmitted to the RDY(B) terminal of the camera body 2. When the lens-side communication unit 340 is connected to the body-side communication unit 240, an RDYL signal from the interchangeable lens 3 is transmitted to the RDY(B) terminal of the camera body 2. The RDYA signal output by the accessory-side control / communication unit 435 is a signal determined and generated by the accessory-side control / communication unit 435. The RDYL signal output by the lens-side communication unit 340 is a signal determined and generated by the lens-side control unit 330.

[0040] The DATAB(B) terminal outputs a data signal (hereinafter referred to as the DATAB signal) to the DATAB(L) terminal of the interchangeable lens 3 or the teleconverter 4. The DATAB(L) terminal is an input terminal that inputs the DATAB signal from the DATAB(B) terminal. Therefore, the DATAB signal from the body-side communication unit 240 is input to the lens-side communication unit 340 or the accessory-side control / communication unit 435.

[0041] The DATAL(B) terminal is an input terminal to which a signal from the DATAL(L) terminal is input. A data signal (hereinafter referred to as the DATAA signal) is input to the DATAL(B) terminal from the DATAL(L) terminal of the teleconverter 4, or a data signal (hereinafter referred to as the DATAL signal) from the DATAL(L) terminal of the interchangeable lens 3 is input via the teleconverter 4. The lens-side communication unit 340 can switch the output of the DATAL(L) terminal of the interchangeable lens 3 to a high impedance state. The accessory-side control / communication unit 435 can switch the output of the DATAL(L) terminal of the teleconverter 4 to a high impedance state. When the accessory-side control / communication unit 435 is connected to the body-side communication unit 240, a DATAA signal from the teleconverter 4 is transmitted to the DATAL(B) terminal of the camera body 2. When the lens-side communication unit 340 is connected to the body-side communication unit 240, a DATAL signal from the interchangeable lens 3 is transmitted to the DATAL(B) terminal of the camera body 2. The DATAA signal output by the accessory-side control / communication unit 435 is a signal determined and generated by the accessory-side control / communication unit 435. The DATAL signal output by the lens-side communication unit 340 is a signal determined and generated by the lens-side control unit 330.

[0042] The CLK(B) terminal is an output terminal that outputs a clock signal (hereinafter referred to as the CLK signal) to the CLK(L) terminal. The CLK(L) terminal is an input terminal that receives the CLK signal from the CLK(B) terminal. The CLK signal from the body side communication unit 240 is input to the lens side communication unit 340 via the teleconverter 4. The CLK signal from the body side communication unit 240 is input to the accessory side control / communication unit 435.

[0043] The HCLK(B) terminal is an input terminal through which a clock signal (hereinafter referred to as the HCLK signal) from the HCLK(L) terminal of the interchangeable lens 3 is input to the body side communication unit 240. The HCLK(L) terminal is an output terminal that outputs the HCLK signal to the HCLK(B) terminal. The HDATA(B) terminal is an input terminal through which a data signal (hereinafter referred to as an HDATA signal) from the HDATA(L) terminal of the interchangeable lens 3 is input to the body side communication unit 240. The HDATA(L) terminal is an output terminal that outputs the HDATA signal to the HDATA(B) terminal.

[0044] The LDET(B) terminal is the above-mentioned attachment detection terminal. In the camera body 2, the LDET(B) terminal is connected to the body side control unit 230 via a resistor R2. A power supply V33 supplied from the power supply unit 250 is connected between the resistor R2 and the body side control unit 230 via a resistor R1. On the other hand, in the interchangeable lens 3, the LDET(L) terminal is connected (grounded) to the GND potential via resistor R3. Also, in the teleconverter 4, the LDET(B) terminal and the LDET(L) terminal are not grounded. In this embodiment, the LDET(L) terminal is provided in the master lens, and the LDET(B) terminal and the LDET(L) terminal are not grounded in the non-master lenses. With this configuration, the LDET(B) terminal is pulled up inside the camera body 2, and is at the potential of the power supply V33 when no interchangeable lens 3 is attached. When an interchangeable lens 3 is attached, the LDET(L) terminal, which is at ground potential, is connected to the pulled-up LDET(B) terminal, and the potential of the LDET(B) terminal drops. This allows the camera body 2 to detect that an interchangeable lens 3 has been attached. Furthermore, when only the teleconverter 4 is attached to the camera body 2 and no interchangeable lens 3 is attached, the LDET(B) terminal remains at the potential of the power supply V33.

[0045] The VBAT(B) terminal is a power supply terminal that supplies power to camera accessories. The lens driver 370 and the aperture driver 380 are driven by power supplied from the VBAT(B) terminal to the VBAT(L) terminal. The lens driver 370 and the aperture driver 380 include actuators such as motors, and therefore require a higher voltage and current than the power supplied to the lens-side controller 330. In the following description, the voltage applied by the power supply unit 250 to the VBAT(B) terminal is referred to as the drive system voltage. The PGND(B) terminal is a ground terminal corresponding to the VBAT(B) terminal. The PGND(B) terminal is connected to the PGND(L) terminal.

[0046] The V33(B) terminal is also a power supply terminal that supplies power to the camera accessory. The power supplied from the V33(B) terminal to the teleconverter 4 is distributed by a power supply circuit 452 to each part of the teleconverter 4, such as the accessory-side control / communication unit 435. In addition, the power output from the power supply circuit 452 is supplied to the V33(L) terminal of the interchangeable lens 3 via a switch 450. The power supplied from the V33(L) terminal to the interchangeable lens 3 is distributed by the power supply circuit 352 to each part of the interchangeable lens 3, such as the lens-side control unit 330.

[0047] The lens side control unit 330 is connected to the V33(B) terminal and operates at a lower voltage and current than the drive system voltage. In the following description, the voltage applied to the V33(B) terminal by the power supply unit 250 is referred to as the circuit system voltage. The GND(B) terminal is a ground terminal corresponding to the V33(B) terminal. As mentioned above, the GND(B) terminal is connected to the GND(L) terminal of the interchangeable lens 3 via a signal line within the teleconverter 4. 3, the direction in which power is supplied is indicated by an arrow. The power generated by the circuit voltage (hereinafter referred to as circuit power) is distributed by the power supply unit 250 to each unit of the camera body 2, such as the body side control unit 230.

[0048] In this embodiment, the power supply circuit 452 of the teleconverter 4 and the switch 450 are inserted and connected in series between the V33(B) terminal of the camera body 2 and the V33(L) terminal of the interchangeable lens 3. When the switch 450 is on, circuit power is supplied to the V33(L) terminal via the power supply circuit 452, and when the switch 450 is off, the supply of circuit power to the V33(L) terminal is cut off. Because circuit power is supplied to the accessory-side control / communication unit 435 upstream of the switch 450, circuit power is supplied regardless of whether the switch 450 is open or closed.

[0049] The switch 450 is controlled to be open from when the accessory-side control / communication unit 435 is started up until the end of device ID allocation command data communication (described later) between the accessory-side control / communication unit 435 and the body-side communication unit 240. The switch 450 is then controlled to be closed after the end of device ID allocation command data communication between the accessory-side control / communication unit 435 and the body-side communication unit 240. Closing the switch 450 connects the camera body 2 to the next camera accessory (interchangeable lens 3 in this embodiment), and circuit power is supplied.

[0050] In the interchangeable lens 3, the VBAT(L) terminal is connected to the power supply circuit 351. The output of the power supply circuit 351 and the PGND(L) terminal are connected to the lens driving unit 370 and the aperture driving unit 380. In addition, the V33(L) terminal is connected to the power supply circuit 352, as described above. The output of the power supply circuit 352 and the GND(L) terminal are connected to the lens side control unit 330 and other units.

[0051] <Command data communication explanation> Next, command data communication will be described with reference to Fig. 4. In command data communication, data signals can be sent and received bidirectionally between the lens side control unit 330 and the body side control unit 230. Here, a first usage example will be defined as a usage pattern in which the interchangeable lens 3 is indirectly attached to the camera body 2 via the teleconverter 4, and a second usage example will be defined as a usage pattern in which the interchangeable lens 3 is directly attached to the camera body 2 without the teleconverter 4. Figure 4 is a diagram illustrating the timing of various signals in the second usage example.

[0052] In this embodiment, two types of command data communication are performed: device ID allocation command data communication and normal command data communication. Device ID allocation command data communication is command data communication performed by the camera body 2 to assign device IDs to camera accessories such as the interchangeable lens 3 and teleconverter 4 attached to the camera body 2. Normal command data communication is command data communication performed after a device ID has been assigned by device ID allocation command data communication (see FIG. 7). In one command data communication, one command packet 402 is sent from the camera body 2 to the camera accessory, and then one data packet 406, 407 is sent and received between the camera body 2 and the camera accessory. Command packet 402 includes data indicating a request for model name information, data indicating a request for a discrimination signal to determine whether the lens is a master lens or a non-master lens, data indicating a device ID indicating the destination of the command data communication, data indicating a request for information regarding the optical characteristics of the camera accessory, data indicating what data will be sent in the next data packet, data indicating the data length of the next data packet, and the like. The data packet 406 sent from the camera body 2 to the camera accessory includes data indicating the amount of drive of the moving parts within the camera accessory, data for conveying the operating status within the camera body 2, data for conveying the device ID, and the like. The data packet 407 sent from the camera accessory to the camera body 2 includes data indicating the model name information of the camera accessory, data indicating a discrimination signal for determining whether the lens is a master lens or a non-master lens, data for conveying the operating status of the moving parts within the camera accessory, data indicating information regarding the optical characteristics of the camera accessory, data indicating the magnification of the teleconverter 4, data indicating the optical characteristics of the interchangeable lens after it is attached to the teleconverter 4, and the like.

[0053] Figure 4 and the following description show command and data communication between the body side communication unit 240 and the lens side communication unit 340, but the command and data communication between the body side communication unit 240 and the accessory side control / communication unit 435 is similar, and in that case, in Figure 4 and the following description, the RDYL signal becomes the RDYA signal, the DATAL signal becomes the DATAA signal, and the lens side communication unit 340 becomes the accessory side control / communication unit 435.

[0054] The lens side communication unit 340 sets the potential of the RDYL signal to L level when command data communication starts. Furthermore, when the lens side communication unit 340 determines that it is now in a state where command data communication can be performed, it keeps the potential of the RDYL signal at L level. Furthermore, when it is not in a state where command data communication can be performed, the lens side communication unit 340 sets the level of the RDYL signal to H level.

[0055] When the RDYL signal is at L level at the start of command data communication (T1), the body side communication unit 240 starts outputting a clock signal 401 as a CLK signal. This causes the clock signal 401 to be transmitted from the camera body 2 to the interchangeable lens 3. The frequency of the clock signal 401 is, for example, 8 MHz.

[0056] The body side communication unit 240 outputs a command packet 402 as a DATAB signal in synchronization with a clock signal 401. In Fig. 4, the command packet 402 is indicated by switching between H level and L level. When transmission of the command packet 402 is complete, the body side communication unit 240 stops outputting the clock signal 401.

[0057] The lens side control unit 330 uses an error detection code (e.g., checksum data) included in the command packet 402 received by the lens side communication unit 340 to determine whether or not there is a communication error in the command packet 402. If it determines that there is no communication error, the lens side communication unit 340 sets the level of the RDYL signal to H level (T2). The lens side control unit 330 then starts a first control process 404 based on the command packet 402.

[0058] When the first control process 404 by the lens side control unit 330 is completed, the lens side communication unit 340 can set the level of the RDYL signal to L level (T3). When the level of the input RDYL signal becomes L level, the body side communication unit 240 outputs a clock signal 405 as a CLK signal.

[0059] The body side communication unit 240 outputs a data packet 406 as a DATAB signal in synchronization with the clock signal 405. In Fig. 4, the data packet 406 is indicated by switching between H level and L level. When the body side communication unit 240 has completed transmission of the data packet 406 of a predetermined length, it stops outputting the clock signal 405 (T4).

[0060] On the other hand, when the clock signal 405 is input, the lens side communication unit 340 outputs a data packet 407 as a DATAL signal in synchronization with the clock signal 405. In Fig. 4, the data packet 407 is indicated by switching between H level and L level.

[0061] The lens side control unit 330 uses an error detection code (e.g., checksum data) included in the data packet 406 received by the lens side communication unit 340 to determine whether or not a communication error has occurred in the data packet 406. If it is determined that there is no communication error, the lens side communication unit 340 sets the level of the RDYL signal to H level again (T4). The lens side control unit 330 then starts the second control process 408 based on the data packet 406.

[0062] <Packet Structure> Fig. 6(a) is a diagram illustrating the structure of the command packet 402, and Fig. 6(b) is a diagram illustrating the structures of the data packets 406 and 407. The command packet 402 and the data packets 406 and 407 each include synchronization data at the beginning. The command packet 402 is, for example, 8 bytes of fixed-length data. "Dev ID" 63 is fixed-length data that includes the device ID of the communication partner. Normally, command data communication is performed after device ID allocation command data, so the command packet 402 is transmitted including the device ID of the communication partner. Therefore, data indicating the device ID of the communication partner is set in "Dev ID" 63. In contrast, in the case of device ID allocation command data communication, the communication is performed before the device ID is allocated, so the command packet 402 is transmitted without specifying the device ID of the communication partner. In this case, in the device ID allocation command data communication, a predetermined initial value is set in "Dev ID" 63, and the command packet 402 remains fixed length.

[0063] "CMD" 64 is fixed-length data indicating instructions, requests, etc. "CMD" 64 contains data indicating instructions or requests from the camera body 2. "Length" 66 is fixed-length data indicating the data length (i.e., the amount of information) of the data packet 406 to be sent next. Since the command packet 402 indicates the data length of the subsequent data packet 406, when receiving the data packet 406, the receiving device (interchangeable lens 3 or teleconverter 4) can detect the synchronization data, measure the data length indicated by "Length" 66, and then finish receiving the data packet 406.

[0064] Data packets 406 and 407 are variable-length data of m bytes, with the number of data pieces indicated by "Length" 66. "DATA1" 72, "DATA2" 73, ..., "DATAn" m-1 are each data pieces divided into 1-byte lengths. The information to be transmitted is set in 1-byte units as "DATA1" 72, "DATA2" 73, .... In the case of data packet 406 for device ID allocation command data communication, data indicating the device ID is set in "DATA1" 72, for example. In the case of data packet 407 for normal command data communication, data indicating information from the camera accessory is set in "DATA1" 72, "DATA2" 73, ..., "DATAn" m-1.

[0065] <Explanation of the first and second control processes> Next, an example of the first control process 404 and the second control process 408 of the command data communication shown in FIG. 4 will be described. For example, suppose the command packet 402 includes an instruction to drive the lens 361. As a first control process 404, the lens-side control unit 330 generates a data packet 407 indicating that it has received the instruction to drive the lens 361. Next, as a second control process 408, the lens-side control unit 330 issues an instruction to the lens driver 370 to move the lens 361 by the amount of movement indicated in the data packet 406. This causes the lens 361 to move in the direction of the optical axis O. When the instruction to move the lens 361 is issued from the lens-side control unit 330 to the lens driver 370, the lens-side communication unit 340 determines that the second control process 408 has been completed and sets the level of the RDYL signal to L (T5). Also, for example, suppose the command packet 402 includes an instruction to start hotline communication. The lens-side control unit 330 generates a data packet 407 indicating that it has received the instruction to start hotline communication, as a first control process 404. Next, the lens-side control unit 330 outputs an instruction to start hotline communication to the lens-side communication unit 340, as a second control process 408, and sets the level of the RDYL signal to L level, marking the second control process 408 as complete (T5).

[0066] <Command data communication processing flow> Next, the flow of command data communication processing when the teleconverter 4 is attached as an accessory will be described. FIG. 7 is a time chart illustrating the flow of processing during device ID allocation command data communication and normal command data communication that occurs after a device ID has been assigned. From top to bottom, FIG. 7 shows the RDYB signal input to the camera body 2, the DATAB signal output from the camera body 2, the RDYA signal output from the accessory control / communication unit 435, the DATAA signal output from the accessory control / communication unit 435, the RDYL signal output from the lens-side control unit 330, and the DATAL signal output from the lens-side control unit 330. The horizontal axis in FIG. 7 represents time. Reference numerals beginning with S in FIG. 7 represent step numbers indicating corresponding processes in the flowcharts of FIGS. 8 and 9. FIG. 8 is a flowchart illustrating the flow of processing executed during device ID allocation command data communication. FIG. 9 is a flowchart illustrating the flow of processing executed during normal command data communication.

[0067] To roughly explain the flow in Figure 7, the period from time t10 to time t20 is the period during which the camera body 2 performs device ID allocation command data communication in turn with the teleconverter 4 and the interchangeable lens 3. Then, the period from time t20 onwards is the period during which the camera body 2 performs normal command data communication individually with the interchangeable lens 3 or teleconverter 4. The body side communication unit 240 performs device ID allocation command data communication with the accessory side control / communication unit 435 from time t10 to time t12, and performs device ID allocation command data communication with the lens side communication unit 340 from time t13 to time t20.

[0068] When the body-side control unit 230 detects that a camera accessory has been attached, it performs device ID allocation command data communication for each attached camera accessory, thereby assigning a device ID to each camera accessory. Thereafter, in normal command data communication, the body-side control unit 230 specifies the device ID of the communication partner in each command data communication. Note that in this embodiment, the body-side control unit 230 assigns a device ID each time the attachment detection terminal detects attachment of a camera accessory or the power is turned on. Therefore, even if a previous device ID was stored in the memory unit in the body-side control unit 230 before performing device ID allocation command data communication, the device ID is reassigned before communication is performed.

[0069] (Device ID allocation command data communication) When the interchangeable lens 3 is indirectly attached to the camera body 2 via the teleconverter 4, the potential at the LDET(B) terminal drops. When the body-side control unit 230 detects this drop in the potential at the LDET(B) terminal, it supplies circuit power to the V33(B) terminal of the teleconverter 4. This supplies power to the accessory-side control / communication unit 435, and at time t10, the accessory-side control / communication unit 435 starts up. The started-up accessory-side control / communication unit 435 changes the RDYA signal from L level → H level → L level (S410), notifying the camera body 2 that it is ready to receive device ID allocation command data communication.

[0070] The body-side control unit 230, notified by the RDYB signal that the teleconverter 4 is in a state where it can receive data, outputs a DATAB signal in synchronization with the clock signal 401 (S230). The DATAB signal at this time includes a command packet 402, which includes an instruction to assign a device ID to the teleconverter 4 and a request for a discrimination signal from the teleconverter 4. Having completed the first control process 404 for the command packet 402, the accessory-side control / communication unit 435 changes the RDYA signal from L level → H level → L level (S425) to notify the camera body 2 that it is in a state where it can receive data. The body-side communication unit 240 outputs a DATAB signal in synchronization with the clock signal 405 (S240). The DATAB signal at this time is a data packet 406, which includes a device ID (for example, device ID1) to be assigned to the teleconverter 4. Upon receiving the data packet 406, the accessory-side control / communication unit 435 stores the device ID1 in the storage unit 437 or holds it in the accessory-side control / communication unit 435 by the second control process 408.

[0071] Meanwhile, the accessory control / communication unit 435 outputs a DATAA signal in synchronization with the clock signal 405 (S430). This DATAA signal includes a data packet 407, which contains the teleconverter 4's identification signal and model name information. In this embodiment, the teleconverter 4's identification signal represents the data contained in the "DATA_1" 72 field as, for example, "01," indicating that the teleconverter 4 is a non-master lens. In other words, by receiving the identification signal (01) from the teleconverter 4, the camera body 2 recognizes that another device (in this example, the interchangeable lens 3) may be attached to the subject side of the camera accessory (teleconverter 4) with which it is currently communicating, so that it can communicate with the camera. The teleconverter 4's identification signal is stored in the memory unit 437. The camera body 2 also associates the device ID 1 assigned to the teleconverter 4 with the model name information received from the teleconverter 4 and stores it in the in-body control unit 230.

[0072] Upon confirming the completion of reception of the data packet 406 (S240) and the completion of transmission of the data packet 406 (S430), the accessory-side control / communication unit 435 changes the RDYA signal from L level to H level again to L level to abandon communication (S445), and cuts off output of the RDYA signal and the DATAA signal within a predetermined time period from time t11 when the signal was changed to L level (t12, S450). Furthermore, the accessory-side control / communication unit 435 turns on the switch 450, i.e., connects circuit power from the power supply circuit 452 to the interchangeable lens 3 (S460). By connecting the circuit power, power is supplied to the interchangeable lens 3, and at time t13, the lens-side control unit 330 is activated. When the lens-side control unit 330 is activated, the interchangeable lens 3 is able to perform device ID allocation command data communication with the camera body 2, and the lens-side control unit 330 performs processing similar to the processing performed by the accessory-side control / communication unit from time t10 to t12. In this embodiment, the discrimination signal of the interchangeable lens 3 is represented by, for example, data contained in the "DATA_1" 72 field, such as "00," indicating that the interchangeable lens 3 is the master lens. In other words, by receiving a discrimination signal (00) from the interchangeable lens 3, the camera body 2 can recognize that no other devices are attached to the subject side of the camera accessory (interchangeable lens 3) with which it is currently communicating and capable of communicating. The discrimination signal of the interchangeable lens 3 is stored in the storage unit 350. The camera body 2 also assigns a device ID (for example, device ID2) to the interchangeable lens 3, associates information received from the interchangeable lens 3 (for example, model name information) with the device ID2 assigned to the interchangeable lens 3, and stores this in the in-body control unit 230. The interchangeable lens 3 also stores the assigned device ID2 in the storage unit 350 or stores it in the lens-side control unit 330. The body-side control unit 230 determines based on the discrimination signal that the device that assigned device ID2 is the master lens and that no other devices are attached to the subject side in a state capable of communication, and therefore terminates the device ID allocation command data communication. By performing device ID allocation command data communication in this manner, the camera body 2 can allocate device IDs to all camera accessories that are attached in a communicable manner, and can also store the acquired model name information in association with the assigned device ID.

[0073] In this embodiment, only the teleconverter 4 to which power is supplied from time t10 to t12 is able to perform device ID allocation command data communication with the camera body 2 and receives a request for device ID allocation and a discrimination signal. On the other hand, the interchangeable lens 3 to which power is not supplied cannot perform device ID allocation command data communication with the camera body 2, and therefore does not receive a request for device ID allocation or a discrimination signal. Therefore, only the accessory control / communication unit 435 can send its own model name information and discrimination signal to the camera body 2. This causes the camera body 2 to assign device ID1 to the teleconverter 4, and associates information received from the teleconverter 4 (e.g., model name information) with the device ID1 assigned to the teleconverter 4 and stores it in the body-side control unit 230. The body-side control unit 230 determines from the discrimination signal that the device to which device ID1 is assigned is a non-master lens and that another device capable of communication may be attached to the subject side, and can therefore begin allocating the next device ID2.

[0074] (Normal command data communication) After completing the device ID allocation command data communication, the body side control unit 230 performs normal command data communication from time t20 onwards. Normal command data communication is performed by the camera body 2 individually designating either the interchangeable lens 3 or the teleconverter 4 as the communication partner. In the example of FIG. 7, the camera body 2 performs normal command data communication with the teleconverter 4 from time t23 to time t32, and performs normal command data communication with the interchangeable lens 3 from time t33 onwards.

[0075] When the body side communication unit 240 detects that the RDYB signal has changed from L level to H level to L level, it outputs the DATAB signal in synchronization with the clock signal 401 (S130). The DATAB signal at this time includes a command packet 402, which contains instructions and requests to the teleconverter 4. Therefore, the command packet 402 includes the device ID 1 corresponding to the teleconverter 4.

[0076] The command packet 402 is received by both the lens side communication unit 340 and the accessory side control / communication unit 435. Upon receiving the command packet 402, the lens side communication unit 340 detects that the command packet 402 contains a device ID2 that is different from its own device ID1, and cuts off output of the RDYL signal and the DATAL signal for a predetermined time (t33) from time t21 when reception of the command packet 402 is completed (S570). The predetermined time for cutting off can also be recognized by the lens side communication unit 340 because the data length of the subsequent data packet 406 is included in the command packet 402. On the other hand, when the accessory-side control / communication unit 435 receives the command packet 402 and detects that its own device ID2 is included in the command packet 402, it sets the output of the RDYA signal and the DATAA signal to a communication-enabled state (t23, S530) within a predetermined time from time t21 when it has completed receiving the command packet 402. The accessory-side control / communication unit 435 changes the RDYA signal from L level → H level → L level (S540) to notify the camera body 2 that it is in a command data communication-enabled state and can receive the subsequent data packet 406.

[0077] The body-side communication unit 240, which has been notified by the teleconverter 4 that it is in a state where it can receive signals, outputs a DATAB signal in synchronization with the clock signal 405 (S140). The DATAB signal at this time includes a data packet 406, which includes data for performing the operation instructed in the command packet 402 that the teleconverter 4 completed receiving at time t21. Meanwhile, the accessory-side control / communication unit 435 outputs a DATAA signal in synchronization with the clock signal 405 (S550). The DATAA signal at this time includes a data packet 407, which can include, for example, the magnification of the focal length of the teleconverter 4, information indicating the optical characteristics of the lens 460, and the optical characteristics of the interchangeable lens when a specific interchangeable lens is attached.

[0078] Next, when the RDYB signal changes from L level to H level to L level, the body side communication unit 240 outputs the DATAB signal in synchronization with the clock signal 401 (S130). The DATAB signal at this time includes a command packet 402, which includes a device ID 2 corresponding to the interchangeable lens 3. The command packet 402 is received by the lens side communication unit 340 and the accessory side control / communication unit 435. When the accessory side control / communication unit 435 confirms that the command packet 402 contains a device ID2 that is different from its own device ID1, it blocks output of the RDYA signal and the DATAA signal within a predetermined time from time t31 when it has completed receiving the command packet 402 (t32, S570). On the other hand, when the lens side communication unit 340 confirms that its own device ID2 is included in the command packet 402, it sets output of the RDYL signal and the DATAL signal to a communication enabled state within a predetermined time from time t31 when it has completed receiving the command packet 402 (t33, S530). The lens side communication unit 340 changes the RDYL signal from L level → H level → L level (S540) to notify the camera body 2 that it is in a reception enabled state.

[0079] The body side communication unit 240, which has been notified by the interchangeable lens 3 that it is in a state where it can receive data, outputs a DATAB signal in synchronization with the clock signal 405 (S140). The DATAB signal at this time includes a data packet 406, which includes data and the like for the interchangeable lens 3 to perform the operation instructed in the command packet 402 that was received at time t31. Meanwhile, the lens side communication unit 340 outputs a DATAL signal (S550) in synchronization with the clock signal 405. The DATAL signal at this time includes a data packet 407, which can include information indicating optical characteristics such as the focal length of the imaging optical system 360 of the interchangeable lens 3, information indicating the operating state of the movable parts, and the like.

[0080] In the second use example, the teleconverter 4 is not attached, and the interchangeable lens 3 is attached directly to the camera body 2. In this case, the processing from time t13 onwards in Figure 7 is carried out as device ID allocation command data communication. Also, the processing from time t33 onwards in Figure 7 is carried out as normal command data communication. In the second use example, only one device ID (for example, device ID1) is assigned to the interchangeable lens 3, and command packets sent from the camera body 2 always include that device ID (device ID1). As a result, the interchangeable lens 3 is able to receive all command data from the camera body 2.

[0081] If there are multiple intermediate accessories between the interchangeable lens 3 and the camera body 2, for example two, device ID allocation command data communication is initiated between the camera body 2 and a first intermediate accessory closer to the camera body 2 before the interchangeable lens 3. Then, after device ID allocation command data communication with the first intermediate accessory has finished, device ID allocation command data communication is initiated with a second intermediate accessory attached to the subject side of the first intermediate accessory (the side farther from the camera body 2). In other words, the communication partner is switched and device ID allocation command data communication is performed. After device ID allocation command data communication with all intermediate accessories attached between the camera body 2 and the interchangeable lens 3 has finished, device ID allocation command data communication is initiated between the camera body 2 and the interchangeable lens 3. That is, if there are multiple intermediate accessories, a process similar to the process from time t10 to t12 in FIG. 7 is performed as device ID allocation command data communication, but before time t13.

[0082] (Processing of the body-side control unit 230 in device ID allocation command data communication) Next, the device ID allocation command data communication process in the camera body 2 will be described with reference to FIG. When the body side control unit 230 performs power-on processing in response to a power-on operation, it starts the device ID allocation command data communication of Fig. 8. In step S210, the body side control unit 230 determines whether the signal at the LDET(B) terminal is at L level, i.e., whether or not an interchangeable lens 3 is attached. If the LDET(B) terminal is at L level, the body side control unit 230 makes a positive judgment in step S210 and proceeds to step S220, where it makes a judgment based on a response from the interchangeable lens 3. If the LDET(B) terminal is at H level, the body side control unit 230 makes a negative judgment in step S210 and waits for the interchangeable lens 3 to be attached while repeating the processing of step S210.

[0083] In step S220, the body side control unit 230 determines whether the RDYB signal has changed from L level → H level → L level. If a change in the RDYB signal is detected, the body side control unit 230 determines that the teleconverter 4 is in a state where reception is possible, makes a positive decision in step S220, and proceeds to step S230. If the body side control unit 230 does not detect the above change, it makes a negative decision in step S220 and repeats the processing of step S220. In step S230, the body side control unit 230 transmits a command packet 402 for device ID allocation command data communication. In step S235, the body side control unit 230 determines whether or not the RDYB signal has changed. When the body side communication unit 240 detects a change from L level → H level → L level, the body side control unit 230 determines that the teleconverter 4 is in a reception-enabled state, makes a positive decision in step S235, and proceeds to step S240. If the body side control unit 230 does not detect the above change, it makes a negative decision in step S235 and repeats the processing of step S235. In step S240, the body side control unit 230 transmits a data packet 406 for device ID allocation command data communication, and also receives a data packet 407 for device ID allocation command data communication from the camera accessory, and proceeds to step S245. The data packet 406 contains data indicating the device ID. Meanwhile, the data packet 407 contains an identification signal and model name information for the camera accessory.

[0084] In step S245, the body side control unit 230 determines whether the RDYB signal has changed. If a change in the RDYB signal from L level → H level → L level is detected, the body side control unit 230 determines that the communication partner is in a state where reception is possible, makes a positive decision in step S245, and proceeds to step S250. If the body side control unit 230 does not detect the above change, it makes a negative decision in step S245 and repeats the processing of step S245. In step S250, the body side control unit 230 associates the transmitted device ID with the model name information of the communication partner and stores the association, and then proceeds to step S260. That is, the body side control unit 230 stores information linking the device ID 1 set in the data packet 406 in S240 with the communication partner "Teleconverter 4."

[0085] In step S260, the body side control unit 230 determines whether the discrimination signal indicates a master lens. That is, the body side control unit 230 determines whether the discrimination signal is 00 or 01. If the discrimination signal indicates a master lens (00), in this embodiment, no other camera accessories are attached in a communicable state on the subject side of the master lens, and therefore it can be determined that device IDs have been assigned to all camera accessories attached in a communicable state. The body side control unit 230 makes a positive judgment in step S260 and ends the device ID allocation command data communication according to FIG. 8. After the device ID allocation command data communication, the process proceeds to normal command data communication in FIG. 9. If the discrimination signal indicates a non-master lens (01), there is a possibility that another camera accessory may be attached in a communicable state on the subject side of the non-master lens, and therefore it cannot be determined that device IDs have been assigned to all camera accessories attached in a communicable state. The body side control unit 230 makes a negative decision in step S260 and returns to step S220. When returning to step S220, the body side control unit 230 repeats the same processing as described above.

[0086] (Accessory side control / communication unit 435 processing in device ID allocation command data communication) Next, the device ID allocation command data communication process in the teleconverter 4 will be described with reference to FIG. When accessory-side control / communication unit 435 is activated by the supply of circuit power and enters a reception-enabled state, it changes the RDYA signal from L level to H level to L level in step S410, and proceeds to step S420.

[0087] In step S420, the accessory-side control / communication unit 435 receives the command packet 402 of the device ID allocation command data communication from the body-side communication unit 240, and proceeds to step S425. In step S425, when the accessory-side control / communication unit 435 is ready to receive the next data packet 406, it changes the RDYA signal from L level → H level → L level, and proceeds to step S430. In step S430, the accessory-side control / communication unit 435 receives the data packet 406 of the device ID allocation command data communication from the body-side communication unit 240, and transmits the data packet 407 to the body-side communication unit 240, and then proceeds to step S440.

[0088] In step S440, the accessory-side control / communication unit 435 stores in the storage unit 437 the device ID assigned to the teleconverter 4 by the camera body 2 in the data packet 406 received in step S430, and proceeds to step S445. In step S445, accessory side control / communication unit 435 completes storing the device ID as first control processing 404, and when it becomes ready to receive, changes the RDYA signal from L level → H level → L level, and proceeds to step S450.

[0089] In step S450, the accessory-side control / communication unit 435 cuts off the output of the RDYA signal and the DATAA signal (setting them to a high impedance state), and proceeds to step S460. In step S460, the accessory-side control / communication unit 435 turns on the switch 450, i.e., supplies circuit power to the interchangeable lens 3, and ends the device ID allocation command data communication in Fig. 8. After the device ID allocation command data communication, the process proceeds to normal command data communication in Fig. 9.

[0090] (Processing of the lens control unit 330 in device ID allocation command data communication) Next, the processing of device ID allocation command data communication in the interchangeable lens 3 will be described with reference to FIG. When the lens side control unit 330 is started up by the supply of circuit power and enters a state where it can receive signals, in step S310, the lens side communication unit 340 changes the RDYL signal from L level → H level → L level, and the process proceeds to step S320.

[0091] In step S320, the lens side control unit 330 receives the command packet 402 of the device ID allocation command data communication from the body side communication unit 240 via the lens side communication unit 340, and proceeds to step S325. In step 325, when the lens side control unit 330 is ready to receive the next data packet 406, the lens side communication unit 340 changes the RDYL signal from L level → H level → L level, and proceeds to step S330. In step S330, the lens side control unit 330 receives a data packet 406 of the device ID allocation command data communication from the body side communication unit 240 via the lens side communication unit 340, and transmits a data packet 407 to the body side communication unit 240, and proceeds to step S340.

[0092] In step S340, the lens side control unit 330 stores the device ID assigned to the interchangeable lens 3 from the camera body 2 by the data packet 406 received in step S330 in the lens side memory unit 350 as the first control process 404, and then proceeds to step S345. In step S345, when the lens side control unit 330 has completed storing the device ID and is ready to receive data, the lens side communication unit 340 changes the RDYL signal from L level → H level → L level, ending the device ID allocation command data communication in Fig. 8. After the device ID allocation command data communication, the process proceeds to normal command data communication in Fig. 9.

[0093] (Processing of the body side control unit 230 in normal command data communication) Next, the normal command data communication process in the camera body 2 will be described with reference to FIG. In step S110, the body side control unit 230 determines the communication partner (i.e., device ID) and proceeds to step S120. At this time, the device ID of the communication partner is held in the body side control unit 230. When issuing instructions or requests to the teleconverter 4, such as drive control within the teleconverter 4 or error check within the teleconverter 4, the body side control unit 230 determines device ID 1, since the teleconverter 4 is the communication partner. Also, when issuing instructions or requests to the interchangeable lens 3, such as initialization such as moving the lens 361 to an initial position by the lens drive unit 370, drive control of the lens 361 by the lens drive unit 370, or error check within the interchangeable lens 3, the interchangeable lens 3 is the communication partner, and device ID 2 is determined.

[0094] In step S120, the body side control unit 230 determines whether the RDYB signal is at H level. In other words, when the body side control unit 230 detects that the device ID allocation process or the second control process in the camera accessory has ended and the RDYB signal has changed from L level → H level → L level, the body side control unit 230 makes a positive decision in step S120 and proceeds to step S130. If the body side control unit 230 does not detect the above change, it makes a negative decision in step S120 and repeats the process of step S120.

[0095] In step S130, the body side control unit 230 transmits a command packet 402 for normal command data communication, and proceeds to step S135. The command packet 402 at this time includes data specifying a device ID. In step S135, the body side control unit 230 determines whether or not the RDYB signal has changed. When the body side control unit 230 detects a change in the RDYB signal from L level → H level → L level, it determines that the communication partner is in a state where it can receive, makes a positive decision in step S135, and proceeds to step S140. When the body side control unit 230 does not detect the above change, it makes a negative decision in step S135 and repeats the processing of step S135. In step S140, the body side control unit 230 causes the data packet 406 for normal command data communication to be transmitted, and also causes the data packet 407 for normal command data communication to be received from the camera accessory with which the communication is being made, and then proceeds to step S145. In step S145, the body side control unit 230 determines whether the RDYB signal has changed. If a change in the RDYB signal from L level → H level → L level is detected, the body side control unit 230 determines that the communication partner is in a state where reception is possible, makes a positive decision in step S145, and proceeds to step S150. If the body side control unit 230 does not detect the above change, it makes a negative decision in step S145 and repeats the processing of step S145.

[0096] In step S150, the body side control unit 230 determines whether or not to perform termination processing. If, for example, a power-off operation has been performed, the body side control unit 230 makes a positive determination in step S150, performs a predetermined power-off process, and terminates the normal command data communication shown in Fig. 9. During the power-off process, the device ID stored in the memory unit 235 is erased. If the body side control unit 230 does not want to perform termination processing, it makes a negative decision in step S150 and returns to step S130. When returning to step S130, the body side control unit 230 repeats the same processing as described above. Note that the body side control unit 230 may also perform step S110, which determines the communication partner, before step S130.

[0097] (Processing of the intermediate accessory control / communication unit 435 and the lens side control unit 330 in normal command data communication) Next, the processing of normal command data communication in the camera accessory will be described with reference to Fig. 9. Hereinafter, the accessory-side control / communication unit 435 and the lens-side control unit 330 will be collectively referred to as the "control unit of the camera accessory." In step S510, the control unit of the camera accessory receives the command packet 402 of normal command data communication from the body side control unit 240, and proceeds to step S520.

[0098] In step S520, the control unit of the camera accessory determines whether the device ID included in command packet 402 matches its own device ID. If its own device ID is included in command packet 402, the control unit of the camera accessory makes a positive decision in step S520 and proceeds to step S530. If its own device ID is not included in command packet 402, the control unit of the camera accessory makes a negative decision in step S520 and proceeds to step S570.

[0099] If command packet 402 is addressed to the camera accessory, the control unit of the camera accessory sets the output of the RDYA signal and DATAA signal, or the output of the RDYL signal and DATAL signal, to a communication-enabled state in step S530, and proceeds to step S540. If the control unit of the camera accessory determines in step S540 that there is no error in receiving command packet 402, it changes the RDYA signal or RDYL signal from L level → H level → L level, and proceeds to step S545. In step S545, the control unit of the camera accessory starts first control process 404 based on command packet 402, and proceeds to step S550.

[0100] In step S550, the control unit of the camera accessory receives the data packet 406 from the body side control unit 240, and transmits the data packet 407 to the body side control unit 240, and then proceeds to step S560. In step S560, if the control unit of the camera accessory determines that there is no error in receiving data packet 406, it changes the RDYA signal or RDYL signal from L level → H level → L level and proceeds to step S565. In step S565, the control unit of the camera accessory starts second control process 408 based on the control content of data packet 406 and returns to step S510.

[0101] If its own device ID is not included in command packet 402, the control unit of the camera accessory makes a negative decision in step S520 and proceeds to step S570. In step S570, the control unit of the camera accessory cuts off the output of the RDYA signal or RDYL signal and the DATAA signal or DATAL signal, and returns to step S510.

[0102] (3rd usage example) In the first and second usage examples, when only a non-master lens is attached to the camera body 2, the potential of the LDET(B) terminal remains at the potential of the power supply V33 and does not drop, and the camera body 2 does not detect that a camera accessory is attached. Also, in the first and second usage examples, the body-side control unit 230 is configured to detect the attachment of the interchangeable lens 3 by detecting a drop in the potential of the LDET(B) terminal and by detecting attachment using a lens attachment / detachment detection pin (not shown) provided on the body-side mount 210. However, the camera body 2 may be configured to detect that a camera accessory is attached even when a non-master lens is attached and no master lens is attached. Hereinafter, a third usage example will be referred to as an example in which the camera body 2 is powered on with the teleconverter 4 attached, and then the interchangeable lens 3 is attached. In the third usage example, the device ID allocation command data communication from step S220 onwards may be started when the camera body 2 is powered on and before the interchangeable lens 3 is attached. In this way, a device ID may be assigned to the teleconverter 4 by processing from time t10 to time t12 when only the teleconverter 4 is attached to the camera body 2, and then after the interchangeable lens 3 is attached, a device ID may be assigned only to the interchangeable lens 3 by processing from time t12 to time t20.

[0103] <Hotline communication explanation> The body-side control unit 230 performs hotline communication with the master lens. The master lens (interchangeable lens 3 in this embodiment) has a moving member inside, and transmits the position and movement status of the moving member via hotline communication that is separate from command data communication. In hotline communication, a data signal (HDATA signal) and a clock signal (HCLK signal) are transmitted unidirectionally from the lens-side control unit 330 to the body-side control unit 230.

[0104] In hotline communication, when an instruction to start hotline communication is sent from the camera body 2 to the interchangeable lens 3 via command data communication, hotline data is sent from the lens side communication unit 340 to the body side communication unit 240 independently of (unrelated to) the command data communication until an instruction to end hotline communication is sent from the camera body 2 to the interchangeable lens 3 via command data communication. The hotline data sent from the lens side communication unit 340 to the body side communication unit 240 is, for example, information about the state of the interchangeable lens 3, and can include position information of the focusing lens of the lens 361, position information of the image stabilization lens, information indicating the control state of the focusing lens, and the like. This information is shown as lens signal 503 in FIG. 5, which will be described below.

[0105] 5 is a diagram illustrating the timing of hotline communication between the body-side communication unit 240 and the lens-side communication unit 340. When the lens-side control unit 330 receives a command to start hotline communication via command data communication (T6), it starts processing 501 to generate data related to lens information. The generation processing 501 is processing to acquire information indicating the state of the interchangeable lens 3 at a sampling period of, for example, 1 millisecond, and generate a signal carrying the acquired information, i.e., lens signal 503.

[0106] When the lens side control unit 330 has completed generating the lens signal 503 (T7), the lens side communication unit 340 outputs the clock signal 502 from the HCLK(L) terminal. This causes the clock signal 502 to be transmitted from the interchangeable lens 3 to the camera body 2. The frequency of the clock signal 502 is, for example, 2.5 MHz.

[0107] The lens side communication unit 340 outputs a lens signal 503 as an HDATA signal in synchronization with the clock signal 502. In Fig. 5, the lens signal 503 is indicated by switching between H level and L level. When the lens side communication unit 340 completes transmission of the lens signal 503 (T8), it stops outputting the clock signal 502 and returns to time T6. The lens side communication unit 340 repeats times T6 to T8 as one hotline cycle. The lens side communication unit 340 repeats the generation process 501 and transmission of the lens signal 503 at regular intervals (for example, every 1 millisecond) until an instruction to end communication (also referred to as an instruction to stop transmission) is transmitted from the camera body 2 via command data communication. The time from time T7 to time T8 does not exceed 80% of the time from time T6 to time T8. In other words, the time required to transmit the lens signal 503 during one hotline communication is set to about 75%, and the data length of the lens signal 503 is set to not exceed 80%. The lens side control unit 330 may also perform the generation process 501 independently of the HCLK signal and HDATA signal. In this case, the generation process 501 does not necessarily have to be performed between T6 and T7.

[0108] Because the command data communication and hotline communication described above allow two types of communication to be performed independently, it is possible to execute each type of communication in parallel. That is, the body-side control unit 230 and the lens-side control unit 330 can start and end hotline communication while performing command data communication. It is also possible to perform command data communication while performing hotline communication. Therefore, the body-side control unit 230 can continuously obtain information about the interchangeable lens 3 through hotline communication even during command data communication. Furthermore, because information about the interchangeable lens 3 can be continuously obtained through hotline communication, the adverse effects of sending and receiving long data through command data communication can be reduced. Furthermore, because hotline communication is available, the body-side control unit 230 can send various instructions and requests to the interchangeable lens 3 at any time and receive information from the interchangeable lens 3 at any time.

[0109] According to the above-described embodiment, the following effects can be obtained. (1) The camera body 2 is configured to allow camera accessories to be attached or detached, into which light from a subject enters, and is equipped with a body-side terminal and a body-side communication unit 240 that communicates with at least one of the attached camera accessories. The body-side communication unit 240 requests, via a communication terminal among the body-side terminals, from the teleconverter 4 a discrimination signal indicating whether or not another device (e.g., an interchangeable lens 3) capable of communicating with the camera body 2 can be attached to the front side (subject side) of the teleconverter 4. With this configuration, it is possible to obtain, from the communicating device, a discrimination signal indicating whether or not a camera accessory is present in front of the communicating device. The discrimination signal is information that determines whether the lens is a master lens or a non-master lens, and in this embodiment is defined as information indicating whether or not another device can be attached to the subject side of the device so as to be able to communicate. Because the camera accessory transmits a discrimination signal to determine whether the lens is a master or non-master lens, the camera body 2 does not need to have a dedicated terminal for distinguishing between master and non-master lenses, nor does it need to determine whether the lens is a master or non-master lens from the model name information of the camera accessory, etc. Since there is no need to have a terminal just for distinguishing between master and non-master lenses, this contributes to the miniaturization of the mount parts of the camera body 2 and camera accessories. Furthermore, the number of terminals on the master lens can be the same as the number of terminals on the non-master lens, which also contributes to the miniaturization of the mount part. Furthermore, because the camera body 2 does not need to determine whether the lens is a master or non-master lens from the model name information of the camera accessory, etc., there is no need to store the model name information of all camera accessories that can be attached to the camera body 2, and it is possible to distinguish whether a lens is a master or non-master lens even for camera accessories developed or released after the camera body 2.

[0110] (2) The camera body 2 includes a storage unit that stores device IDs for identifying the interchangeable lens 3 and the teleconverter 4. This configuration allows the device IDs of camera accessories connected to the camera body 2 to be managed appropriately.

[0111] (3) The body-side communication unit 240 instructs the interchangeable lens 3 to use a command packet 402 to assign device ID2, and instructs the teleconverter 4 to use a command packet 402 to assign device ID1. Because device ID allocation command data communication and normal command data communication are not performed in parallel, device IDs can be assigned appropriately to the communication partners, and in subsequent normal command data communication, the desired communication partner can be specified simply by using the device ID. Furthermore, in command data communication, the camera accessory's control unit transmits data packet 407 in parallel with receiving data packet 406. In this way, while the command packet 402 is unidirectional, the data packet is bidirectional, so a means of data communication from the camera accessory to the camera body 2 can also be ensured for command data communication. Furthermore, in this embodiment, a device ID is assigned each time the power is turned on or an accessory is attached or detached, and is assigned in the order in which the accessories are attached to the camera body 2. Therefore, the camera body 2 does not always assign the same device ID to a specific camera accessory.

[0112] (4) The body-side communication unit 240 performs normal command data communication using a device ID. This configuration allows the device ID to be used to specify the recipient of the instruction, enabling the instruction to be sent appropriately. If the device ID were not used, the camera accessory would need to determine whether the instruction from the camera body 2 is intended for it, which could lengthen the time it takes for the desired camera accessory to receive the instruction when multiple camera accessories are attached. Furthermore, if the device ID were not used, the camera accessory might not be able to determine whether the instruction from the camera body 2 is intended for it, which could result in the desired camera accessory being unable to receive the instruction. However, according to this embodiment, the desired camera accessory can receive the instruction at the appropriate time.

[0113] (5) The body-side communication unit 240 ends the device ID allocation command data communication when the discrimination signal indicating whether or not another device capable of communicating with the camera body 2 can be attached to the front side (subject side) of the camera accessory indicates that it cannot be attached. After the device ID allocation command data communication ends, the body-side control unit 230 instructs the camera accessory to start initialization processing, etc., via normal command data communication. The initialization processing is, for example, processing such as moving driven parts such as the lens 361 to their initial positions. In this embodiment, the device ID allocation command data communication is terminated after a determination signal indicating that no other devices can be attached to the front is received, so it is possible to assign device IDs to all of the camera accessories attached to the camera body 2. Since normal command data communication can be started after device IDs have been assigned to all of the attached camera accessories, communication using device IDs can be performed with all of the camera accessories attached so that they can communicate.

[0114] (6) If the discrimination signal indicates that another device capable of communicating with the camera body 2 can be attached to the front side (subject side) of the camera accessory, the body side communication unit 240 communicates with the other device via that camera accessory. With this configuration, the interchangeable lens 3 can communicate with the camera body 2 via the teleconverter 4, eliminating the need to provide separate terminals for communicating with the camera body 2 and the teleconverter, and allowing for the mount to be made smaller.

[0115] (7) The body-side communication unit 240 indicates the device ID of the interchangeable lens 3 via the terminal of the teleconverter 4. With this configuration, the device ID can be properly communicated to the camera accessory even when an intermediate accessory is attached.

[0116] (8) After starting device ID allocation command data communication, the body-side communication unit 240 instructs the camera accessory to which it will first assign a device ID (the teleconverter 4 in this embodiment) to assign device ID1 as the device ID, and then instructs the camera accessory to which it will next assign an identifier (the interchangeable lens 3 in this embodiment) to assign device ID2 as the device ID. Device ID1 is used by the teleconverter 4 to recognize instructions addressed to it and to distinguish them from instructions addressed to the interchangeable lens 3. Device ID2 is used by the interchangeable lens 3 to recognize instructions addressed to it and to distinguish them from instructions addressed to the teleconverter 4. In this way, since different device IDs are assigned to multiple camera accessories in order, starting with the camera accessory closest to the camera body 2, device IDs can be assigned appropriately to multiple communication partners.

[0117] (9) The camera body 2 is equipped with a power supply unit 250 that supplies power to the power supply circuit 452 of the attached teleconverter 4 and the power supply circuit 352 of the interchangeable lens 3. With this configuration, it is possible to appropriately supply power to multiple communication partners using a single power supply unit 250 in the camera body 2.

[0118] (10) A camera accessory into which light from a subject is incident is configured to be detachably attached to the camera body 2. For example, the teleconverter 4 includes an accessory control / communication unit 435 that communicates with the camera body 2 and a memory unit 437 that stores a discrimination signal (e.g., 01) indicating that another camera accessory (e.g., interchangeable lens 3) that can communicate with the camera body 2 can be attached to the front side of the teleconverter 4 (i.e., the subject side), and the accessory control / communication unit 435 sends the discrimination signal to the camera body 2. The interchangeable lens 3 also includes a lens communication unit 340 that communicates with the camera body 2 and a lens memory unit 350 that stores a discrimination signal (e.g., 00) indicating that another camera accessory that can communicate with the camera body 2 cannot be attached to the front side (subject side) of the interchangeable lens 3, and the lens communication unit 340 sends the discrimination signal to the camera body 2. This configuration allows the camera body 2 to easily determine whether another camera accessory can be attached to the front side of the camera accessory so that communication is possible.

[0119] (11) A camera accessory into which light from a subject is incident is detachable from the camera body 2 and includes a communication unit that communicates with the camera body 2. The camera accessory stores a discrimination signal indicating whether other devices capable of communicating with the camera body 2 are attached to the subject side of the camera accessory, and the communication unit transmits the discrimination signal to the camera body 2. In other words, the master lens stores a discrimination signal indicating that other devices capable of communicating with the camera body 2 are not attached to the subject side, and the non-master lenses store a discrimination signal indicating that other devices capable of communicating with the camera body 2 may be attached to the subject side. This configuration allows the camera accessory to appropriately notify the camera body 2 of information indicating whether other camera accessories capable of communicating with the subject are present on the subject side. Because the discrimination signal is stored for each camera accessory, there is an advantage that the camera body does not need to memorize the distinction between master and non-master lenses for each camera accessory.

[0120] (12) Each camera accessory has a storage unit that stores a device ID for distinguishing it from other camera accessories. With this configuration, the camera accessory can properly store its own device ID and properly receive instructions from the camera body 2.

[0121] (13) The camera accessory has an identification unit (the accessory control / communication unit 435 in the case of the teleconverter 4, or the lens control unit 330 in the case of the interchangeable lens 3) that identifies whether the command packet 402 sent from the camera body 2 contains its own device ID stored in the memory unit. This configuration makes it possible to appropriately determine whether the command packet 402 sent from the camera body 2 is addressed to the camera accessory or to someone else.

[0122] (14) If the camera accessory includes its own device ID in command packet 402, it determines that the command data communication is addressed to itself and receives data packet 406. If the camera accessory were to receive data packet 406 that includes a device ID different from its own device ID, there is a risk that the drive instruction from the camera body 2 will not be executed correctly by the intended camera accessory, or that data packet 407 will be sent from an unintended camera accessory to the camera body 2. In this embodiment, with the configuration described above, it is possible to properly receive command packet 402 addressed to itself and the subsequent data packet 406 sent from the camera body 2.

[0123] (15) If the camera accessory does not include its own device ID in the command packet 402, it places the communication terminal in a high impedance state and does not receive the data packet 406. With this configuration, it is possible to avoid receiving the data packet 406 when the instruction or request sent from the camera body 2 is addressed to someone else.

[0124] (16) The camera accessory has a lens-side terminal on the side opposite to the subject side (the imaging surface side). The accessory-side control / communication unit 435 and the lens-side communication unit 340 communicate with the camera body 2 via the lens-side terminal.

[0125] (17) The teleconverter 4 is provided with a body-side terminal on the subject side for communicating with the interchangeable lens 3, a lens-side terminal on the opposite side of the optical axis O from the subject side, a signal line connecting the lens-side terminal and the body-side terminal, and an accessory-side control / communication unit 435 that can switch communication via the signal line between a communication enabled state (a state in which a signal is output) and a communication abandoned state (a high-impedance state in which no signal is output). This configuration makes it possible to avoid, for example, a collision on the signal line between the RDYL signal output from the interchangeable lens 3 and the RDYA signal output from the teleconverter 4.

[0126] (18) The teleconverter 4 and the interchangeable lens 3 have an optical system that passes light from the subject side.

[0127] (19) The teleconverter 4 includes a plurality of lens-side terminals provided in the rear terminal holding portion 422 on the camera body 2 side, a plurality of body-side terminals provided in the front terminal holding portion 423 on the interchangeable lens 3 side, at least one power supply signal line connecting at least one of the lens-side terminals to at least one of the body-side terminals, and a switch 450 for opening and closing the power supply signal line. According to this embodiment, the number of connection terminals (11) between the camera body 2 and the interchangeable lens 3 is equal to the number of connection terminals (11) between the teleconverter 4 and the interchangeable lens 3, so there is no need to increase the number of terminals. The camera body 2 to which the teleconverter 4 is attached is equipped with a group of body-side terminals and a power supply unit 250 that supplies power to the teleconverter 4 via a V33(B) terminal that is connected to a power supply signal line on which a switch 450 is provided in the teleconverter 4. With this configuration, the body-side control unit 230 can supply power from the camera body 2 to the teleconverter 4 when the switch 450 is open, and can supply power from the camera body 2 to the teleconverter 4 and the interchangeable lens 3 when the switch 450 is closed.

[0128] (20) The camera body 2 further includes a body-side communication unit 240 that communicates with the accessory-side control / communication unit 435 via a communication terminal among the group of body-side terminals. When the body-side communication unit 240 receives a change in the RDYA signal or RDYL signal from L level to H level to L level, it starts device ID allocation command data communication. With this configuration, it is possible to wait until the powered camera accessory becomes capable of communication before allocating a device ID from the camera body 2 to the camera accessory.

[0129] (21) In the first usage example, when the second control process 408 is completed in the device ID allocation command data communication and the switch 450 is closed, the power supply unit 250 supplies power to the interchangeable lens 3 via the power supply V33(B) terminal. Furthermore, the body-side communication unit 240 communicates with the lens-side communication unit 340 via the communication terminal, and when it receives a change in the RDYL signal (L level → H level → L level) from the supplied interchangeable lens 3 indicating whether command data communication is possible or not, it sends a command packet 402 including a device ID to the interchangeable lens 3. With this configuration, it is possible to assign a device ID to the interchangeable lens 3 from the camera body 2 after waiting for the powered interchangeable lens 3 to become able to communicate.

[0130] (22) The camera accessory attached to the camera body 2 includes a communication unit that communicates with the body-side communication unit 240 via a communication terminal. The communication unit of the camera accessory switches the RDYL signal or RDYA signal, and the DATAL signal or DATAA signal, between a communication-disabled state (high impedance state) and a communication-enabled state. This configuration makes it possible to prevent, for example, the RDYL signal output from the interchangeable lens 3 and the RDYA signal output from the teleconverter 4 from colliding on the signal line.

[0131] (23) The camera accessory's communication unit enables communication through the input units (communication terminals DATAB and CLK) that receive the DATAB signal and CLK signal from the camera body 2. This configuration allows the interchangeable lens 3 and teleconverter 4 to properly receive the CLK signal and DATAB signal output from the camera body 2.

[0132] (24) When a command packet 402 including a device ID addressed to itself is input from the camera body 2, the communication unit of the camera accessory switches the output unit (communication terminals RDY(L), DATAL(L)) to a communication enabled state. With this configuration, the communication unit waits for the command packet 402 including a device ID addressed to itself to be input, and then switches the output unit to a communication enabled state. This makes it possible to appropriately avoid collisions on the signal lines between, for example, the signals (RDYL, DATAL) output from the interchangeable lens 3 and the signals (RDYA, DATAA) output from the teleconverter 4.

[0133] (25) When a command packet 402 including a device ID addressed to another person is input from the camera body 2 to the communication unit of the camera accessory, that is, when a command packet 402 including a device ID addressed to the camera accessory is not input to the input unit, the communication unit switches the output unit (communication terminals RDY(L), DATAL(L)) to a communication abandon state (high impedance state). This configuration makes it possible to appropriately avoid, for example, a collision on the signal line between the signal (RDYL, DATAL) output from the interchangeable lens 3 and the signal (RDYA, DATAA) output from the teleconverter 4.

[0134] (26) The teleconverter 4 attached between the camera body 2 and the interchangeable lens 3 comprises a lens terminal provided in the rear terminal holding portion 422 on the camera body 2 side, a body terminal provided in the front terminal holding portion 423 on the interchangeable lens 3 side, multiple signal lines connecting the lens terminal and the body terminal, and a switch 450 provided on one of the signal lines for opening and closing the signal line. With this configuration, for example, when the switch 450 is open, the signal line from the camera body 2 to the interchangeable lens 3 is cut off and only the signal line from the camera body 2 to the teleconverter 4 is open, and when the switch 450 is closed, the signal line from the camera body 2 to the interchangeable lens 3 via the teleconverter 4 is open.

[0135] (27) In the teleconverter 4, the switch 450 is provided on at least one of the signal lines supplied from the power supply unit 250 of the camera body 2. With this configuration, when the switch 450 is open, power can be supplied from the camera body 2 to the teleconverter 4. When the switch 450 is closed, power can be supplied from the camera body 2 to the teleconverter 4 and the interchangeable lens 3.

[0136] (28) In the teleconverter 4, the switch 450 is a normally open contact, so that when the switch 450 is initially open, power is supplied from the camera body 2 only to the teleconverter 4, and when the switch 450 is closed, power is supplied from the camera body 2 to the teleconverter 4 and the interchangeable lens 3.

[0137] (29) In the teleconverter 4, the accessory-side control / communication unit 435 puts the output unit for the communication signal lines (signal lines for the RDYA signal and DATAA signal) into a communication abandon state (high impedance state) before closing the switch 450. With this configuration, for example, even if the RDYL signal is output from the interchangeable lens 3 to the communication signal line by closing the switch 450, it is possible to prevent the RDYL signal from colliding with the RDYA signal output from the output unit of the teleconverter 4 on the signal line.

[0138] (30) The camera body 2 assigns device IDs to all camera accessories attached so that they can communicate, and then specifies the device ID in normal command data communication to send a command packet 402 and a data packet 406 from the body-side communication unit 240. With this configuration, the camera body 2 can specify a communication partner and communicate with a device that has been assigned a device ID that matches the specified device ID.

[0139] 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. Although the camera body 2 in this embodiment is a mirrorless type, it may also be a single-lens reflex type. The storage unit in this embodiment may be volatile or non-volatile. The device ID may be held and temporarily stored in a control unit (body-side control unit 230, accessory-side control / communication unit 435, lens-side control unit 330), or may be temporarily stored in a storage unit (storage units 235, 437, 350). Note that the time for which the device ID is stored only needs to include at least the time the accessory is attached, and it is not necessary to continue storing the device ID after the accessory is removed or the power is turned off. In this embodiment, the lens driving unit 370 moves the focusing lens along the direction of the optical axis O, but this can be modified as appropriate. If the multiple lenses 361 include a zoom lens, the lens driving unit 370 may include a zoom driving unit. Furthermore, if the multiple lenses 361 include a shake correction lens for reducing the effects of shake caused by camera shake or the like, the lens driving unit 370 may include a shake correction lens driving unit. In this embodiment, power is supplied by the drive system voltage only to the interchangeable lens 3 and not to the teleconverter 4, but drive system power may also be supplied to the teleconverter 4. In this embodiment, the instruction to assign a device ID to the camera accessory and the instruction to send an identification signal to the camera accessory are contained in one command packet 402, but these may be separated into two command packets. In this case, the camera accessory prepares separate data packets 407, one containing model name information and one containing the identification signal. In this embodiment, device IDs are assigned to all camera accessories attached to the camera body 2 in the order in which they are connected to the camera body 2 (starting with the camera accessory closest to the camera body 2), but this is not limited to this. In this embodiment, when the teleconverter 4 and interchangeable lens 3 are attached to the camera body 2 as shown in Figures 2 and 3, the body-side control unit 230 assigns a device ID to the teleconverter 4, and then assigns a device ID to the interchangeable lens 3. This order is the same (unchanged) whether the teleconverter 4 is attached alone to the camera body 2, and then the interchangeable lens 3 is attached to the teleconverter 4 integrated with the camera body 2, or whether the interchangeable lens 3 is attached to the teleconverter 4, and then the teleconverter 4 integrated with the interchangeable lens 3 is attached to the camera body 2. In this embodiment, the power-on process is performed in response to a power-on operation, and the device ID allocation command data communication is started, but this is not limited to this. In this embodiment, the teleconverter 4 has been described as an example of a non-master lens. However, the non-master lens is not limited to the teleconverter 4. For example, a wide-angle converter, a close-up ring, or the like may also be used. In other words, the teleconverter 4 may be any intermediate accessory that is attached between the camera body 2 and the master lens. While lens hoods and front converters can be attached to the subject side of the master lens, they are not considered to be devices that are attached in a communicative state because they do not communicate with the camera body 2. Another example of a master lens is an adapter that converts communication standards to the camera body 2. An adapter is used when an interchangeable lens that conforms to a different communication standard is attached to the subject side, but when communicating with the camera body 2, the adapter converts the communication standard and sends instructions to the interchangeable lens that conforms to the different communication standard. Therefore, from a communication perspective, the adapter may also be used as a master lens. Note that being communicatively attachable means being able to receive instructions from the camera body 2 and respond appropriately to those instructions. Therefore, in this embodiment, components such as lens caps and hoods that can be physically attached to the subject side of a camera accessory are not considered to be "camera accessories that can be communicatively attached." Also, interchangeable lenses of other communication standards can be attached to the camera body 2 via a mount adapter, but in this case, the interchangeable lenses of other communication standards cannot respond appropriately even if they receive instructions directly from the camera body 2, and the mount adapter must convert the instructions from the camera body 2. Therefore, in this embodiment, the interchangeable lenses of other communication standards are not considered to be "camera accessories that can be communicatively attached." In this embodiment, the accessory-side control / communication unit 435 is not connected to the HCLK(B) terminal, HCLK(L) terminal, HDATA(B) terminal, and HDATA(L) terminal. Therefore, from the perspective of the camera body 2, the only partner in hotline communication is the interchangeable lens 3, and a one-to-one relationship is maintained. Therefore, although it was decided that the device ID of the communication partner is not to be specified in hotline communication, this is not limited to this. In this embodiment, one teleconverter 4 is attached as an intermediate accessory, but multiple intermediate accessories may be attached. Also, an upper limit (for example, two) may be set on the number of intermediate camera accessories.

[0140] Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments that are conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention. [Explanation of symbols]

[0141] 1...camera system, 2...camera body, 3...interchangeable lens, 4...accessory, 210...body side mount, 230...body side control unit, 235...storage unit, 240...body side communication unit, 270...signal processing unit, 310...lens side mount, 330...lens side control unit, 340...lens side communication unit, 350...lens side memory unit, 352, 452...power supply circuit, 360...imaging optical system, 402...command packet, 406, 407...data packet, 412...rear side mount, 413...front side mount, 435...control / communication unit, 437...memory unit, 450...switch, 460...lens

Claims

[Claim 1] A camera system having at least one accessory and a camera body capable of communicating with the accessory, a camera body having a body-side mount; an accessory including an accessory-side mount detachable from the body-side mount and a receiver that receives an instruction signal transmitted from the camera body; the instruction signal includes identification information and an instruction from the camera body, A camera system in which the identification information is information for identifying an accessory that is attached to the body mount and is capable of communicating with the camera body.

Images