JP2012154967A - Image pickup apparatus, interchangeable lens, and image pickup apparatus system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera capable of further improving an operation performance, while accommodating to an old type interchangeable lens using a conventional communication system, and to provide an interchangeable lens.SOLUTION: An image pickup apparatus mountable with an interchangeable lens includes: control means that can switch between a first communication mode for outputting a clock signal from a first terminal and communicating with the lens via a second terminal based on the clock signal, and a second communication mode for communicating with the lens via the first terminal or the second terminal without using the clock signal; and detecting means for detecting whether the mounted interchangeable lens has a first lens side terminal accommodated with the first terminal or not. When the detecting means does not detect the first lens side terminal in the interchangeable lens, the control means communicates with the second communication mode.

Description

  The present invention relates to an imaging apparatus in which an interchangeable lens can be attached and exchanges information by communication, an interchangeable lens that can be attached to the imaging apparatus, and an imaging apparatus system.

  Conventionally, clock-synchronized serial communication (synchronous serial communication) has been adopted as a communication method between a camera and an interchangeable lens. Patent Document 1 discloses the following technical contents. First, synchronous serial communication is performed at a first communication speed at which communication is possible even with an old type interchangeable lens. When it is determined that the attached interchangeable lens is a new lens according to the communication content, the communication is switched to synchronous serial communication at a higher second communication speed. In addition, it is also described that the communication terminal circuit is switched from an open drain type to a CMOS type suitable for high-speed communication when the communication speed is switched. According to this technology, it is possible to operate with a combination with an old type interchangeable lens even though the speed is low, and with a combination with a new type interchangeable lens, it is possible to realize an improvement in communication speed at a certain level.

JP-A-9-304804

  By the way, in the conventional synchronous serial communication, in order to set the data to be sent to the camera in the next communication by analyzing the data received by the lens between the communication, and to execute processing based on the received data A waiting time is provided. The state in which this waiting time has occurred is called Busy, and the lens does not accept communication from the camera during Busy. For this reason, even if the clock frequency is increased, the microcomputer on the camera side communicates while waiting for the lens busy to be released, so there is a limit to the improvement of the operation performance. On the other hand, the camera on the lens side frequently generates a communication interrupt from the camera, and each time a Busy signal is output and a communication interrupt process for cancellation must be preferentially performed. It becomes.

  An object of the present invention is to provide a camera and an interchangeable lens that can further improve the operation performance while supporting an old type interchangeable lens using a conventional communication system.

  In order to achieve the above object, a first invention of the present application is an imaging apparatus to which an interchangeable lens can be attached, the first terminal and the second terminal for communicating with the attached interchangeable lens, and the first A first communication mode in which a clock signal is output from one terminal and communication is performed at the second terminal based on the clock signal, and communication is performed at the first terminal or the second terminal without using the clock signal. Control means capable of switching between the two communication modes, and detection means for detecting whether or not the mounted interchangeable lens has a first lens side terminal corresponding to the first terminal. When the detection unit does not detect that the interchangeable lens has the first lens side terminal, the imaging device performs communication in the second communication mode.

  A second invention of the present application is an imaging apparatus system that includes an imaging apparatus body and an interchangeable lens that is detachably attached to the imaging apparatus body, and the imaging apparatus body and the interchangeable lens can communicate with each other. The imaging device includes a first terminal and a second terminal for communicating with an attached interchangeable lens, outputs a clock signal from the first terminal, and outputs the second signal based on the clock signal. It is possible to switch between a first communication mode in which communication is performed using a terminal and a second communication mode in which communication is performed using the first terminal or the second terminal without using a clock signal, and the interchangeable lens is connected to the first terminal. If the interchangeable lens is compatible with the second communication mode after performing communication in the first communication mode, the interchangeable lens is switched to the second communication mode. Second communication mode The first communication mode is continued when the mode does not correspond to the communication mode, and communication is performed in the second communication mode when the interchangeable lens does not have a terminal corresponding to the first terminal. It is a device system.

  According to the present invention, it is possible to provide a camera and an interchangeable lens that can further improve the operation performance while supporting an old type interchangeable lens using a conventional communication method.

The figure showing the circuit structure of the camera which implemented this invention, and an interchangeable lens Microcomputer circuit block diagram Block diagram of communication control circuit The figure showing the circuit structure of the communication connection part of the camera and interchangeable lens in Example 1. FIG. 3 is a flowchart of the lens type discrimination operation of the camera in the first embodiment. Camera System Operation Flowchart with Camera Implementing the Present Invention and Interchangeable Lens Operation flowchart of camera-side microcomputer embodying the present invention Operation flowchart of camera-side microcomputer embodying the present invention Operational flow chart of lens-side microcomputer embodying the present invention Timing chart of communication signal between camera and interchangeable lens in baud rate adjustment Timing chart of communication signal between camera and interchangeable lens in asynchronous communication Timing chart of communication signal between camera and interchangeable lens in synchronous communication Operation flowchart of camera-side microcomputer in synchronous communication Operation flowchart of lens-side microcomputer in synchronous communication Operational flow chart of asynchronous communication of the camera embodying the present invention The figure showing the circuit structure of the communication connection part of the camera and interchangeable lens in Example 2.

<Example 1>
FIG. 1 is a diagram showing a circuit configuration of a camera and an interchangeable lens embodying the present invention. In FIG. 1, reference numeral 1 denotes a camera, and reference numerals 2 and 3 denote interchangeable lenses that are detachably attached to the camera 1. The camera 1 has a mount portion 4 as a connection portion, and the interchangeable lenses 2 and 3 have a lens mount portion 5 as a lens connection portion. Inside the camera 1, there are a battery 11, a power generation unit 12, and a camera-side microcomputer 13. The power generation unit 12 receives the voltage output from the battery 11, generates a power supply voltage that is optimally stabilized so that the electric circuit such as the camera-side microcomputer 13 operates, and supplies this to each part of the electric circuit. . Normally, the camera 1 includes a photometric sensor for exposure control, a distance measuring sensor for autofocus control, an image sensor for taking a digital image, its drive circuit, an AD conversion circuit, an image processing circuit, and the like. However, it is not shown because it is not deeply related to the gist of the present invention.

  Reference numerals 14 to 18 denote contact portions provided on the mount portion 4 on the camera 1 side for exchanging electrical signals with the interchangeable lens. Reference numeral 14 denotes a camera-side power supply terminal for supplying the lens power generated by the power generation unit 12 to the interchangeable lens. Reference numeral 15 denotes a camera side CLK terminal for transmitting a synchronous clock signal or the like when the camera and the interchangeable lens communicate with each other, 16 denotes a camera side DOC terminal for transmitting communication data from the camera to the interchangeable lens, and 17 denotes from the interchangeable lens. It is a camera side DOL terminal for receiving communication data to the camera. The camera side CLK terminal 15 corresponds to a first terminal, and the camera side DOC terminal 16 and the camera side DOL terminal 17 correspond to a second terminal. These terminals 15 to 17 are connected to the camera-side microcomputer 13. Reference numeral 18 denotes a camera-side ground terminal which is equipotential with the negative side of the battery 11. Reference numeral 19 denotes a temperature sensor that outputs information about the temperature in the camera. The temperature output is connected to the camera-side microcomputer 13.

A lens-side microcomputer 21 is provided inside the interchangeable lens 2 shown in FIG. 1A, and performs overall control of the interchangeable lens 2 and communication control with the camera 1. Reference numerals 24 to 28 denote contact portions provided on the lens mount portion 5 on the lens 2 side for exchanging electrical signals with the camera. Reference numeral 24 denotes a lens-side power supply terminal for receiving power supply from the camera 1. Reference numeral 26 denotes a lens side DOC terminal for receiving communication data from the camera 1 to the interchangeable lens 2, and reference numeral 27 denotes a lens side DOL terminal for transmitting communication data from the interchangeable lens 2 to the camera 1. Reference numeral 28 denotes a lens side ground terminal.
When the interchangeable lens 2 is normally attached to the camera 1, the camera-side terminals 14, 16, 17, 18 and the lens-side terminals 24, 26, 27, 28 are each 1 as shown in FIG. Connected to pair 1.

On the other hand, inside the interchangeable lens 3 shown in FIG. 1B, there is a lens-side microcomputer 31 that performs overall control of the interchangeable lens 3 and communication control with the camera 1. Reference numerals 34 to 38 denote contact portions provided in the lens mount portion 5 on the lens 3 side for exchanging electrical signals with the camera. Reference numeral 34 denotes a lens-side power supply terminal for receiving power supply from the camera 1. Reference numeral 35 denotes a lens-side CLK terminal for transmitting a synchronous clock signal or the like when communicating with the camera 1, 36 denotes a lens-side DOC terminal for receiving communication data from the camera 1 to the interchangeable lens 3, and 37 denotes an interchangeable lens 3. This is a lens-side DOL terminal for transmitting communication data from the camera 1 to the camera 1. The lens side CLK terminal 35 corresponds to a first lens side terminal. Reference numeral 38 denotes a lens side ground terminal.
When the interchangeable lens 3 is normally attached to the camera 1, the camera-side terminals 14 to 18 and the lens-side terminals 34 to 38 are connected one-on-one as shown in FIG.

The present invention can also be applied when optical communication or wireless communication is performed between a camera and an interchangeable lens.
FIG. 2B shows a configuration related to serial communication control among circuit configurations built in the camera-side microcomputer 13 or the lens-side microcomputer 31. The camera-side microcomputer 13 and the lens-side microcomputer 31 are naturally different from each other, but the configuration related to the serial communication control may have the same configuration requirements, and will be described with reference to the common drawings.

  Reference numeral 41 denotes an oscillator, for example, a crystal oscillator or a ceramic vibrator. Such an oscillator is not limited to being built in a microcomputer but may be externally attached. Reference numeral 42 denotes a clock generation circuit which is connected to the oscillator 41 to generate a source oscillation clock, a multiplication circuit which converts the source oscillation clock to a higher frequency, and frequency division / synthesis based on the converted high frequency clock. And a clock generation circuit that generates clocks of various frequencies. A communication control circuit 43 controls the overall communication, and when using a terminal connected as an IO output port, sets an output level and determines an input level. Details will be described later with reference to FIG. Reference numeral 44 denotes a counter / timer circuit that counts the number of pulses of the input signal and measures the time width of the input signal. The clock signal generated by the clock generation circuit 42 is supplied to the communication control circuit 43 and the counter / timer circuit 44. Reference numerals 45 to 47 denote IO control circuits which switch data input / output directions, input / output signal types and input / output circuit forms of input / output signals of the input / output terminals 55 to 57, respectively. Data input / output direction switching is literally switching between using a terminal as a data input or data output. The input / output signal type switching is switching between connecting an input / output signal of a normal parallel IO signal to a terminal or connecting an input / output signal to / from the communication control circuit 43 to a terminal. The switching of the input / output circuit form is performed by switching between the output using the open drain method or the CMOS method described in Patent Document 1 described above and switching whether or not the pull-up resistor is connected. The IO control circuit 45 performs input / output switching of the input / output terminal 55, and a synchronous clock signal SCLK is connected from the communication control circuit 43, and this SCLK signal can be supplied to the counter / timer circuit 44. The IO control circuit 46 performs input / output switching of the input / output terminal 56, and a serial communication data output signal TXD is connected from the communication control circuit 43. The IO control circuit 47 performs input / output switching of the input / output terminal 57, and a serial communication data input signal RXD is connected from the communication control circuit 43.

  An interrupt control circuit 48 is connected to interrupt generation signals from the communication control circuit 43 and the counter / timer circuit 44. Reference numeral 50 denotes a data bus in the microcomputer. The communication control circuit 43, the counter / timer circuit 44 and the IO control circuits 45 to 47 described above are connected to the data bus 50 and can exchange data necessary for the operation. In the microcomputer, there are other circuit configurations such as an ALU, a program counter, a ROM, a RAM, and an AD converter other than those shown in the figure, but they are not shown.

  In the case of the camera-side microcomputer 13, the input / output terminal 55 is connected to the camera-side CLK terminal 15 in FIG. 1, the input / output terminal 56 is connected to the camera-side DOC terminal 16, and the input / output terminal 57 is connected to the camera-side DOL terminal 17. .

  In the case of the lens-side microcomputer 31, the input / output terminal 55 is connected to the lens-side CLK terminal 35 in FIG. 1B, the input / output terminal 56 is connected to the lens-side DOL terminal 37, and the input / output terminal 57 is connected to the lens-side DOC terminal 36. Connected. This is because in the description of the present embodiment, the DOC signal is transmission data from the camera to the lens, and the DOL signal is transmission data from the lens to the camera.

  On the other hand, FIG. 2A shows a configuration related to serial communication control among circuit configurations built in the lens-side microcomputer 21. In the case of the interchangeable lens 2, the lens-side microcomputer 21 does not have terminals corresponding to the IO control circuit 45 and the input / output terminal 55 of FIG. The other configuration is the same as the configuration of the lens side microcomputer 31 shown in FIG.

  FIG. 3 is a diagram for explaining a more detailed configuration of the communication control circuit 43 shown in FIGS. 2 (A) and 2 (B). Clock signals of various frequencies generated by the clock generation circuit 42 are input to the baud rate generator 61. The baud rate generator 61 generates a clock signal necessary for communication control according to various communication setting data sent through the data bus 50. The communication setting data includes switching between communication master and slave, switching between synchronous communication and asynchronous communication, synchronous clock frequency setting for synchronous communication, asynchronous sampling clock frequency setting for asynchronous communication, and the like. When the synchronous communication and the communication master are set by the communication setting data, the synchronous clock signal SCLK according to the synchronous clock frequency setting value in the case of synchronous communication is output. When the synchronous communication and the communication slave are set by the communication setting data, the synchronous clock signal SCLK is input. The synchronous clock signal SCLK is also supplied to 62 transmission / reception control blocks. When asynchronous communication is set by the communication setting data, a sampling clock according to the asynchronous sampling clock frequency setting in the case of asynchronous communication is supplied to the transmission / reception control block 62. The transmission / reception control block 62 also supplies a shift clock to a transmission shift register 63 and a reception shift register 64, which will be described later, according to various communication setting data transmitted through the data bus 50, and inputs / outputs a transmission / reception trigger signal for serial communication. Perform timing control. An interrupt signal is also generated at the completion timing of serial communication transmission / reception.

  Reference numeral 63 denotes a transmission shift register which inputs data to be transmitted by serial communication in parallel and serially outputs it as a signal TXD. A shift clock for serial output is supplied from the transmission / reception control block 62. When performing asynchronous communication, a transmission trigger signal is input from the transmission / reception control block 62. A reception shift register 64 serially inputs a data signal RXD received by serial communication and outputs it in parallel. A shift clock for serial input is supplied from the transmission / reception control block 62. When performing asynchronous communication, a reception trigger signal is output to the transmission / reception control block 62. A transmission data register 65 receives transmission data from the data bus 50 and sets data in the transmission shift register 63. Reference numeral 66 denotes a reception data register which receives reception data from the reception shift register 64 and can output it to the data bus 50.

As for the interchangeable lens 3 having the lens-side CLK terminal 35, a case of a conventional lens that cannot handle asynchronous communication and a case of a new lens that can support asynchronous communication are assumed. When the interchangeable lens 3 having the lens-side CLK terminal 35 is attached to the camera 1, synchronous communication is first performed so as to be able to cope with both a conventional lens and a new lens.
A control flow when the camera-side microcomputer 13 performs synchronous communication as the first communication mode with the interchangeable lens according to the communication protocol shown in FIG. 12 will be described with reference to FIG.

  (Step 301) The input level of the terminal that outputs the synchronous clock signal CLK is checked to determine whether or not the lens side is not in the Busy state. In this example, the state in which the lens side has this terminal at the L level is the Busy state, and in this state, the camera cannot communicate with the lens. When the input level of the terminal that outputs the signal CLK is H level and the lens side is not in the Busy state, the process proceeds to (Step 302).

  (Step 302) First, data DATA_C1 to be transmitted to the lens is set in the transmission data register, and serial communication for one transmission unit is performed. Normally, data DATA_C1 transmitted to the lens is a certain command to the lens, and response data from the lens responding thereto is data DATA_L2 at the time of communication of the next one transmission unit. Since data DATA_L1 sent from the lens to the camera at the same timing as sending DATA_C1 to the lens is don't care data, it is not particularly read and treated.

  (Step 303) The input level of the terminal that outputs the synchronous clock signal CLK is checked to determine whether or not the lens side is not in the Busy state. While the lens side analyzes the content of the transmitted data DATA_C1 and performs a corresponding process, the lens outputs the CLK signal to the L level and enters the Busy state. Therefore, the processing is completed and the lens side is not in the Busy state. (Step 304).

  (Step 304) Next, data DATA_C2 to be transmitted to the lens is set in the transmission data register, and serial communication in one transmission unit is performed. When the data DATA_C1 transmitted in (Step 302) is a command for transmitting lens-specific information to the camera to the lens, the content of the data DATA_C2 is don't care data, and the data sent from the lens for return. DATA_L2 is meaningful.

(Step 305) The received data DATA_L2 is taken into the reception data register.
The above is the basic operation flow of the microcomputer on the camera side when communicating with the interchangeable lens.

  Next, a control flow when the microcomputer 31 on the interchangeable lens side performs synchronous communication with the camera according to the communication protocol shown in FIG. 12 will be described with reference to FIG. The lens-side microcomputer 31 becomes a slave side for communication. It is detected that serial communication of one transmission unit from the camera has been received by a communication interrupt function that generates an interrupt signal when a predetermined number of falling edges of the synchronous clock signal CLK are counted.

  (Step 401) First, the terminal for receiving the synchronous clock signal CLK is set to L level so that the camera can determine that the lens side is in the Busy state.

  (Step 402) The transmission data DATA_C1 from the camera input to the reception data register is input, and the content is analyzed. Note that the transmission data from the camera is initially DATA_C1, but since DATA_C2 or the like may be sent after that, it is described as DATA_Cx in the flowchart.

  (Step 403) When the content of the transmission data DATA_C1 from the camera is a driving command for the actuator on the lens side, the process proceeds to (Step 404).

  (Step 404) The actuator on the lens side is driven according to the content of the transmission data DATA_C1 from the camera.

  (Step 405) It is determined whether or not the processing related to driving of the actuator on the lens side is completed and communication from the next camera can be received. If reception is possible, the process proceeds to (step 407).

  When the content of the transmission data DATA_C1 from the camera is a lens-specific data transmission request in the above (Step 403), the process proceeds to (Step 406).

  (Step 406) The lens-specific data requested according to the transmission data DATA_C1 from the camera is set in the transmission data register.

  (Step 407) The terminal that receives the synchronous clock signal CLK is set to H level so that the camera can determine that the lens side is no longer in the Busy state.

  The operation flow in the case where synchronous communication is performed between the camera 1 and the interchangeable lens 3 has been described above.

  Next, communication of a camera system composed of a camera implementing the present invention and an interchangeable lens when the lens 3 with the CLK terminal is attached will be described. The operation flow of each of the microcomputer on the camera side and the interchangeable lens side will be described later. First, the overall operation flow will be described with reference to the communication setting operation flowchart of FIG.

  When the camera-side microcomputer 13 detects that the lens 3 with the CLK terminal is attached, the operation starts from (Step 101) in FIG. The method for detecting whether or not the attached lens has a CLK terminal will be described later in detail.

  (Step 101) The camera-side microcomputer 13 sets the communication control circuit 43 and the IO control circuits 45 to 47 so as to perform synchronous communication compatible with the conventional lens and the new lens as the initial setting of the communication method with the interchangeable lens. Do. With this setting, when communication is performed in the camera side microcomputer 13, the communication synchronous clock SCLK signal is output from the input / output terminal 55 as a communication master. In the camera-side microcomputer 13, the transmission data TXD signal from the camera to the interchangeable lens is output from the input / output terminal 56, and the transmission data RXD signal from the interchangeable lens to the camera is input from the input / output terminal 57.

  Even if the interchangeable lens is a new lens capable of asynchronous communication, as an initial setting, a slave setting for synchronous communication is performed in the communication control circuit 43 and the IO control circuits 45 to 47. With this setting, the lens-side microcomputer 31 is set to input the communication synchronization clock SCLK signal from the input / output terminal 55. In addition, in the lens-side microcomputer 31, the transmission data TXD signal from the interchangeable lens to the camera is output from the input / output terminal 56, and the transmission data RXD signal from the camera to the interchangeable lens is input from the input / output terminal 57. .

  (Step 102) Communication is performed between the camera and the interchangeable lens in a synchronous manner. The timing chart of the synchronous communication and the operation flow of the camera side microcomputer 13 and the lens side microcomputer 31 are as shown in FIGS.

  With this communication, the camera side transmits a lens information transmission command for knowing whether or not the type or name of the interchangeable lens or a new type capable of asynchronous communication to the interchangeable lens in DATA_C1. When the interchangeable lens side receives the lens information transmission command, the interchangeable lens side transmits lens information corresponding to the command to the camera using DATA_L2.

  (Step 103) The camera-side microcomputer 13 analyzes the received lens information DATA_L2, and determines whether or not the currently mounted interchangeable lens is compatible with asynchronous communication. If it is determined that the currently mounted interchangeable lens is compatible with asynchronous communication, the camera-side microcomputer 13 proceeds to (Step 104).

  (Step 104) The camera communicates with the interchangeable lens again in a synchronous manner, and transmits a command so as to output a pulse to be measured for baud rate adjustment when performing asynchronous communication.

  When receiving this command, the lens side outputs a pulse to be measured by the camera for baud rate adjustment when performing asynchronous communication. An example of a timing chart regarding the output of the baud rate adjusting pulse is shown in FIG. When the camera-side microcomputer 13 transmits a command requesting output of a baud rate adjustment pulse to the interchangeable lens using the camera-side transmission data DATA_C1 in FIG. 10, the lens-side microcomputer 31 receives the data and receives the command. During the analysis, the normal Busy output is temporarily performed by setting the CLK signal to the L output. Thereafter, when the command analysis can be performed and the next communication can be received, the CLK signal is set to the H level to release the Busy and notify the camera.

  When the CLK signal becomes H level and the camera-side microcomputer 13 knows that the lens-side Busy is released, it transmits transmission data DATA_C2. In this case, the transmission data DATA_C2 is don't care data, and is simply transmitted as a timing trigger for outputting a baud rate adjusting pulse to the lens side.

  When the transmission side DATA_C2 is received and a communication interrupt occurs, the lens side microcomputer 31 immediately outputs the baud rate adjusting pulse Tmes by setting the CLK signal to L output. The baud rate adjusting pulse Tmes is output for a time corresponding to a predetermined clock count of the operation clock generated by the oscillation circuit 42 of the lens side microcomputer 31. For example, if the operation clock generated by the oscillation circuit 42 of the lens-side microcomputer 31 is 10 MHz and 65536 clocks are output as the baud rate adjusting pulse Tmes, 6.5536 msec. This pulse output is performed for a period of time. If the operation clock generated by the oscillation circuit 42 of the lens-side microcomputer 31 is 10.1 MHz due to an error factor of the circuit element, the time width of the baud rate adjusting pulse Tmes is 6.487 msec. Thus, the accuracy deviation of the oscillation frequency of the oscillation circuit of the lens side microcomputer 31 is reflected in the time width of this pulse.

  The camera-side microcomputer 13 starts the falling edge of the input / output terminal 55 after transmitting the transmission data DATA_C2, ends the rising edge of the terminal, and measures the time by the counter / timer circuit 44. The time of the baud rate adjusting pulse Tmes Measure.

  If the camera-side microcomputer 13 performs time measurement by the counter / timer circuit 44 with a 16 MHz clock, 6.5536 msec. Is 104857 counts, and 6.487 msec. This time is 103819 counts. Also, if the camera side microcomputer 13 performs time measurement by the counter / timer circuit 44 with a clock of 16.16 MHz, 6.5536 msec. Is 105906 counts, and 6.487 msec. This time becomes 104857 counts. Therefore, by measuring the time of the baud rate adjusting pulse Tmes, the camera-side microcomputer 13 can know the deviation of the oscillation frequency accuracy of the lens-side microcomputer 31 relative to its own oscillation frequency accuracy.

  (Step 105) The camera-side microcomputer 13 considers the relative oscillation frequency accuracy deviation of the lens-side microcomputer 31 based on the count value of the baud rate adjusting pulse Tmes obtained in (Step 104), and performs asynchronous communication. Adjust the baud rate.

  As an example, assume that the baud rate of asynchronous communication decided in advance is 19200 bps. When the oscillation frequency of the oscillation circuit of the lens-side microcomputer 31 is 10 MHz with no deviation, the lens-side microcomputer 31 can send and receive asynchronous communication data at a baud rate of 1920 bps. However, in the case of the lens-side microcomputer 31 oscillating at 10.1 MHz due to an error factor of the circuit element, even if the baud rate is set to 19200 bps, the frequency deviation is 19392 bps. In the case of asynchronous communication, since there is no synchronous clock, if these two baud rate deviations are not within a predetermined range, a data sampling error occurs and normal transmission / reception cannot be performed. Therefore, the camera side microcomputer 13 sets an optimum baud rate in accordance with the relative deviation of the oscillation frequency accuracy of the lens side microcomputer 31.

  (Step 106) The camera-side microcomputer 13 changes the setting of the communication system with the interchangeable lens, and sets the communication control circuit 43 and the IO control circuits 45 to 47 so as to perform asynchronous communication.

  The lens side microcomputer 31 also changes the setting of the communication method with the camera, and sets the communication control circuit 43 and the IO control circuits 45 to 47 so as to perform asynchronous communication.

  After executing this step, communication between the camera and the interchangeable lens is performed by asynchronous communication as the second communication mode. FIG. 11 is an example of a communication timing chart in asynchronous communication. When transmitting a lens information transmission request command or a lens-side actuator drive command from the camera side to the lens side, an asynchronous data pattern at the baud rate set in the DOC signal is output. In many cases, an L level start bit is output first, and then a predetermined number of bits of data are output at a set baud rate. When the output of a predetermined number of bits is completed, an H-level stop bit is output and transmission is completed. There is no need to output the CLK signal, and there is no need to receive the DOL signal at the same time.

When the lens side transmits lens information to the camera in response to a command transmitted from the camera side, this is also converted to the DOL signal at any timing if the lens side is ready for data transmission without using the CLK signal. This is done by outputting this. The communication protocol is the same as in the case of the DOC signal.
By switching to such an asynchronous communication method, it is not necessary to perform the Busy release confirmation performed for each basic transmission unit between the camera side microcomputer 13 and the lens side microcomputer 31.

  This is the end of the description of the setting operation flow relating to the communication of the camera system including the camera and the interchangeable lens.

Next, an operation flow regarding communication setting with the interchangeable lens on the camera side microcomputer 13 side will be described with reference to a flowchart starting from FIG.
When the camera-side microcomputer 13 starts operating after communicating the lens 3 with the CLK terminal and communicates with the interchangeable lens, the operation flow from (step 111) in FIG. 7 is executed.

  (Step 111) As described in the operation flow (step 101) of the camera system of FIG. 6, the communication control circuit 43 and the IO control circuits 45 to 47 are initially set so as to perform synchronous communication. Therefore, the input level of the terminal that outputs the synchronous clock signal CLK, which is a procedure for performing synchronous communication, is checked to determine whether the lens side is not in the Busy state. When the input level of the terminal that outputs the signal CLK is H level and the lens side is not in the Busy state, the process proceeds to (Step 112).

  (Step 112) First, data DATA_C1 to be transmitted to the interchangeable lens is set in the transmission shift register to perform synchronous communication. The content of DATA_C1 is a lens information transmission command for knowing whether or not the interchangeable lens is a new type compatible with the type and name of the interchangeable lens or asynchronous communication.

  (Step 113) The input level of the terminal that outputs the synchronous clock signal CLK is checked to determine whether or not the lens side is not in the Busy state. While the lens side analyzes the content of the transmitted data DATA_C1 and performs the corresponding processing, the lens outputs the CLK output terminal to the Busy state. The process proceeds to (Step 114) after waiting for the processing to be completed and the lens side not to be in the Busy state.

  (Step 114) The don't care data DATA_C2 is set in the transmission shift register to perform synchronous communication.

  (Step 115) When DATA_C2 is transmitted in the previous step, DATA_L2, which is lens information sent from the interchangeable lens, is input from the reception shift register.

  (Step 116) The lens information input in the previous step is analyzed to determine whether or not the currently mounted interchangeable lens is compatible with asynchronous communication. If the camera-side microcomputer 13 determines that the currently mounted interchangeable lens is compatible with asynchronous communication, the process proceeds to (step 151) in FIG.

  (Step 151) The camera-side microcomputer 13 checks the input level of the terminal that outputs the synchronous clock signal CLK, and determines whether or not the lens side is not in the Busy state. If the input level of the terminal that outputs the signal CLK is H level and the lens side is not in the Busy state, the process proceeds to (Step 152).

  (Step 152) Data DATA_C1 to be transmitted to the interchangeable lens is set in the transmission shift register to perform synchronous communication. The content of DATA_C1 is a command for requesting the interchangeable lens to output a pulse to be measured for baud rate adjustment when performing asynchronous communication.

  (Step 153) The input level of the terminal that outputs the synchronous clock signal CLK is checked to determine whether or not the lens side is in the Busy state. When the input level of the terminal that outputs the signal CLK is H level and the lens side is not in the Busy state, the process proceeds to (Step 154).

  (Step 154) The don't care data DATA_C2 is set in the transmission shift register to perform synchronous communication.

  (Step 155) As described in Step (Step 104) of FIG. 4, immediately after reception of this data DATA_C2, the interchangeable lens outputs the CLK signal to the L output to output the baud rate adjusting pulse Tmes. When the baud rate adjusting pulse Tmes is output, time measurement by the counter / timer circuit 44 is started.

  (Step 156) When the interchangeable lens sets the CLK signal to H output and the output of the baud rate adjusting pulse Tmes is completed, the time measurement by the counter / timer circuit 44 is completed. By inputting the measurement value by the counter / timer circuit 44, the camera-side microcomputer 13 obtains information on the deviation of the oscillation frequency accuracy of the lens-side microcomputer 31 relative to its own oscillation frequency accuracy.

  (Step 157) The baud rate at the time of performing asynchronous communication is determined according to the deviation value from the ideal value measured by the counter / timer circuit 44.

  (Step 158) The camera-side microcomputer 13 changes the setting of the communication method with the interchangeable lens, and sets the communication control circuit 43 and the IO control circuits 45 to 47 so as to perform asynchronous communication. The baud rate determined in the previous step is set in the communication control circuit 43.

  Thereafter, communication with the interchangeable lens is performed by the asynchronous communication method as described in FIG.

  If it is determined in (Step 116) in FIG. 7 that the interchangeable lens is a lens that does not support asynchronous communication, the steps described in FIG. Continue communication with the lens.

  Next, an operation flow related to information communication with the camera on the lens side microcomputer 31 side will be described with reference to a flowchart shown in FIG.

  When the interchangeable lens 3 is attached to the camera 1 and receives power supply from the camera and the lens-side microcomputer 31 becomes operable, as described in FIG. 6 (step 101), it is initially set as the slave side of the synchronous communication. Complete the settings for communication control circuit 43 and IO control circuits 45-47. In this state, when an interrupt due to synchronous communication from the camera occurs, the operation flow from (Step 201) is executed.

  (Step 201) The terminal that receives the synchronous clock signal CLK is set to L level so that the camera can determine that the lens side is in the Busy state.

  (Step 202) The transmission data DATA_C1 from the camera input to the reception shift register is input, and the content is analyzed. Note that the transmission data from the camera is initially DATA_C1, but since DATA_C2 or the like may be sent after that, it is described as DATA_Cx in the flowchart.

  (Step 203) When the content of the transmission data DATA_C1 from the camera is a lens-side actuator drive command, the process proceeds to (Step 204).

  (Step 204) According to the content of the transmission data DATA_C1 from the camera, the lens side actuator is driven.

  (Step 205) It is determined whether or not the processing related to driving of the actuator on the lens side is completed and communication from the next camera can be received. If reception is possible, the process proceeds to step 208.

  If the content of the transmission data DATA_C1 from the camera is not a lens-side actuator drive command in the step (step 203), the process proceeds to (step 206).

  (Step 206) It is determined whether or not the content of the transmission data DATA_C1 from the camera requests the output of the baud rate adjustment pulse Tmes for switching to asynchronous communication. If the output of the baud rate adjusting pulse Tmes is not requested, the process proceeds to step 207 because it is a lens information data transmission request.

  (Step 207) The requested lens information data is set in the transmission shift register in accordance with the transmission data DATA_C1 from the camera. If the requested lens information is lens information for knowing whether or not the type and name of the interchangeable lens is a new type capable of asynchronous communication, the information data is set.

  (Step 208) The terminal that receives the synchronous clock signal CLK is set to the H level so that the camera can determine that the lens side is no longer in the Busy state.

  If the content of the transmission data DATA_C1 from the camera requests the output of the baud rate adjustment pulse Tmes for switching to asynchronous communication in the above (step 206), the process proceeds to (step 209).

  (Step 209) As described in (Step 104) of FIG. 6, the lens side microcomputer 31 sets a predetermined count value for outputting the baud rate adjusting pulse Tmes in the counter / timer circuit 44. If set, the camera waits for transmission data DATA_C2 as a timing trigger for outputting a baud rate adjusting pulse from the camera. When this data is received, the process proceeds to (Step 210).

  (Step 210) At the same time when the counter / timer circuit 44 starts counting, the terminal that receives the synchronous clock signal CLK is set to L level. As soon as the counter / timer circuit 44 finishes counting the predetermined value, the terminal that receives the synchronous clock signal CLK is set to the H level. This completes the output of the baud rate adjusting pulse Tmes.

  (Step 211) The lens-side microcomputer 31 changes the setting of the communication method with the camera, and sets the communication control circuit 43 and the IO control circuits 45 to 47 so as to perform asynchronous communication.

Thereafter, communication with the camera is performed by the asynchronous communication described with reference to FIG.
Note that there may be a case where an interchangeable lens that supports asynchronous communication is attached to a camera that does not support asynchronous communication. In this case, a command requesting the output of the baud rate adjustment pulse Tmes is transmitted from the camera side. Never come. Therefore, the above steps (Step 209) to (Step 211) are not executed. Therefore, in such a case, synchronous communication is continued.

  The camera-to-lens communication setting when the interchangeable lens 3 having the lens-side CLK terminal 35 is attached to the camera has been described above. According to the above configuration, when an interchangeable lens capable of asynchronous communication is attached to a camera capable of asynchronous communication, switching the communication method from synchronous communication to asynchronous communication causes a problem of waiting time due to busy during synchronous communication. Can be improved.

  Here, in the configuration of the camera and lens capable of asynchronous communication, synchronous communication is first performed to check whether the lens supports asynchronous communication. After switching to asynchronous communication, the synchronous clock signal CLK The CLK terminal as a terminal for communicating is no longer necessary.

  The technical idea of the present application resides in the interchangeable lens 2 having no CLK terminal as shown in FIG. Since the interchangeable lens 2 is assumed to perform asynchronous communication from the beginning, there is no need to receive a synchronous clock signal from the camera. Therefore, the CLK terminal for receiving the synchronous clock signal is not provided.

  When the interchangeable lens 2 having no CLK terminal is attached to a camera capable of asynchronous communication, asynchronous communication is performed from the beginning. The setting of the camera-lens communication method when the interchangeable lens 2 is attached to the camera will be described below.

  Prior to that, a method of identifying on the camera side whether or not the mounted interchangeable lens has a CLK terminal will be described.

  FIG. 4 is a diagram illustrating a connection configuration between the camera and the interchangeable lens illustrated in FIG. 1 and a method for identifying the mounted interchangeable lens. Reference numeral 71 denotes a MOSFET having a gate as a control terminal connected to the microcomputer 13 of the camera. Reference numeral 72 denotes a pull-down resistor connected to the camera-side CLK terminal 15 and connected to the ground by the MOSFET 71. Reference numeral 73 denotes a MOSFET whose control terminal gate is connected to the microcomputer 13 of the camera, and 74 is a pull-down resistor connected to the camera-side DOC terminal 16 and connected to the ground by the MOSFET 73. The MOSFET 71 and the MOSFET 73 are connected to the ground by being electrically connected to the camera side ground terminal 18.

  FIG. 4A shows a case where the interchangeable lens 2 having no CLK terminal is attached. A pull-up resistor 75 is connected to the lens-side DOC terminal 26 and pulls up the signal line to the power source.

  FIG. 4B shows a case where the interchangeable lens 3 having the CLK terminal is attached. Reference numeral 76 denotes a pull-up resistor for pulling up the lens-side CLK terminal 35 to a power source, and reference numeral 77 denotes a pull-up resistor for pulling up the lens-side DOC terminal 36 to a power source.

  In FIG. 4A, the resistance ratio between the pull-down resistor 72 and the pull-up resistor 75 is set to about 10: 1. When the MOSFET 71 is turned on and the pull-down resistor 72 is enabled, when the lens 3 is attached to the camera-side CLK terminal 15, the voltage at the camera-side CLK terminal 15 becomes about 9/10 of the power supply voltage, and High and Determined. Further, when the lens 2 is attached or when nothing is connected, the lens-side terminal is not connected to the camera-side CLK terminal 15. Therefore, the voltage at the camera-side CLK terminal 15 becomes the GND level and is determined to be Low.

  In FIG. 4B, the resistance ratio between the pull-down resistor 74 and the pull-up resistors 76 and 77 is set to about 10: 1. When the MOSFET 73 is turned on and the pull-down resistor 74 is enabled, when the lens 2 or 3 is attached to the camera, the voltage of the camera-side DOC terminal 16 becomes about 9/10 of the power supply voltage and is determined as High. The Further, when no lens is mounted, the lens side terminal is not connected to the camera side DOC terminal 16. Therefore, the voltage of the camera side DOC terminal 16 becomes the GND level and is determined to be Low.

  In this configuration, the camera-side microcomputer 13 controls the MOSFET 71 and the MOSFET 73 to detect whether a lens signal line is connected to the camera-side CLK terminal 15 and the camera-side DOC terminal 16.

  FIG. 5 is a flowchart regarding attached lens determination of a camera system composed of a camera and an interchangeable lens according to the present invention. A flow of attached lens determination in the camera-side microcomputer 13 will be described. When a power switch (not shown) is turned on and the camera and the interchangeable lens become operable, the operation starts from (Step 001) in the flowchart.

  (Step 001) The MOSFETs 71 and 73 are turned on to enable the pull-down resistors 72 and 74, and the process proceeds to (Step 002).

  (Step 002) The voltage of the camera side DOC terminal 16 is detected. If it is High, the process proceeds to (Step 003). If it is not High, the process proceeds to (Step 006).

  (Step 003) The voltage of the camera side CLK terminal 15 is detected. If it is High, the process proceeds to (Step 004). If it is not High, the process proceeds to (Step 005).

  (Step 004) Since the camera-side CLK terminal 15 and the camera-side DOC terminal 16 are pulled up, the lens-side CLK terminal 35 is connected to the camera-side CLK terminal 15, and the lens-side DOC terminal is connected to the camera-side DOC terminal 16. 36 is connected. Therefore, it is determined that the lens 3 having the communication CLK terminal is attached, and the process proceeds to (Step 007).

  (Step 005) Since the camera side CLK terminal 15 is not pulled up, nothing is connected to the camera side CLK terminal 15. On the other hand, since the camera side DOC terminal 16 is pulled up, the lens side DOC terminal 26 is connected to the camera side DOC terminal 16. Accordingly, it is determined that the lens 2 having no communication CLK terminal is attached, and the process proceeds to (Step 007).

  (Step 006) Since neither the camera-side CLK terminal 15 nor the camera-side DOC terminal 16 is pulled up, nothing is connected to the respective terminals, and it is determined that no lens is attached (step 007).

  (Step 007) The MOSFETs 71 and 73 are turned off to end the mounted lens detection operation.

  When it is determined in (Step 004) that the lens 3 with the CLK terminal is attached, the operation starts from (Step 101) in the flowchart of FIG. 6 described above, and synchronous communication is first performed. Note that a means for detecting the voltages of the camera side CLK terminal 15 and the camera side DOC terminal 16 may be provided separately and connected to the camera side microcomputer 13.

  Alternatively, the pull-down resistor 74 may be connected to the camera-side DOL terminal 17, the pull-up resistor 75 may be connected to the lens-side DOL terminal 27, and the pull-up resistor 77 may be connected to the lens-side DOL terminal 37. In this case, the camera-side microcomputer 13 can determine whether or not the interchangeable lens is attached based on the voltage of the camera-side DOL terminal 17.

Further, the method for determining whether or not the interchangeable lens is attached is not limited to the above method.
FIG. 15 is a setting operation flowchart regarding communication of the camera system including the camera and the interchangeable lens when the lens 2 without the CLK terminal described in FIG. 5 is attached. The operation flow of each of the camera side and interchangeable lens side microcomputers will be described later. First, this figure will be described as the overall operation flow.
When it is detected in the operation of FIG. 5 that the lens 2 without the CLK terminal is attached, the operation starts from (Step 501) of the flowchart.

  (Step 501) The communication control circuit 43 and the IO control circuits 45 to 47 are set so as to perform asynchronous communication, and the process proceeds to (Step 502). At this time, the baud rate for communication is set to a predetermined standard value, for example, 19200 bps.

  (Step 502) Asynchronous communication is performed between the camera and the interchangeable lens, and the process proceeds to (Step 503). With this communication, the camera side transmits a lens information transmission command for knowing the type and name of the interchangeable lens to the interchangeable lens using DATA_C1.

  When the interchangeable lens side receives the lens information transmission command, the interchangeable lens side transmits lens information corresponding to the command to the camera using DATA_L2.

  (Step 503) It is determined whether or not the communication performed in (Step 502) is established. If established, the process proceeds to (Step 510), and if not established, the process proceeds to (Step 504).

  (Step 504) Although the communication performed in (Step 502) is not established, there is a possibility that the cause is a deviation of the baud rate. Therefore, in order to find a baud rate at which communication is possible, the baud rate is changed (Step 505). Proceed to

  Generally, communication can be performed normally up to a baud rate deviation of about 5%. However, if a difference of more than this occurs, communication cannot be performed correctly, so that the baud rate set in the asynchronous communication setting in (Step 501) is not exceeded. Set a baud rate about 5% higher. For example, when the setting in (Step 501) is 19200 bps, a baud rate of about 20160 bps is set.

  (Step 505) Asynchronous communication is performed between the camera and the interchangeable lens, and the process proceeds to (Step 506). With this communication, the camera side transmits a lens information transmission command for knowing the type and name of the interchangeable lens to the interchangeable lens with DATA_C1.

  When the interchangeable lens side receives the lens information transmission command, the interchangeable lens side transmits lens information corresponding to the command to the camera using DATA_L2.

  (Step 506) It is determined whether or not the communication performed in (Step 505) has been established. If it is established, the process proceeds to (Step 510), and if not established, the process proceeds to (Step 507).

  (Step 507) Although the communication performed in (Step 505) is not established, there is a possibility that the cause is a difference in the baud rate. Therefore, the baud rate is changed to search for a baud rate that can be communicated (Step 508). move on.

  Generally, communication can be performed normally up to a baud rate deviation of about 5%. However, if a difference of more than this occurs, communication cannot be performed correctly, so that the baud rate set in the asynchronous communication setting in (Step 501) is not exceeded. Set a baud rate about 5% lower. For example, if the setting in (Step 501) is 19200 bps, a baud rate of about 18240 bps is set.

  (Step 508) Asynchronous communication is performed between the camera and the interchangeable lens, and the process proceeds to (Step 509). With this communication, the camera side transmits a lens information transmission command for knowing the type and name of the interchangeable lens to the interchangeable lens with DATA_C1.

  When the interchangeable lens side receives the lens information transmission command, the interchangeable lens side transmits lens information corresponding to the command to the camera using DATA_L2.

  (Step 509) It is determined whether or not the communication performed in (Step 508) has been established. If established, the process proceeds to (Step 510), and if not established, the process proceeds to (Step 511).

  (Step 510) Settings are made so that communication will continue at the baud rate at which communication has been established so far, and communication settings for the interchangeable lens 2 having no CLK terminal are terminated.

  (Step 511) The baud rate is changed and communication is performed several times. However, since communication is not established, communication error processing is performed and the process is terminated.

  In the above description, the baud rate is changed once up and down. However, the baud rate can be changed a plurality of times to search for a baud rate that allows communication over a wider range.

  In the foregoing, the communication setting between the camera and the lens when the interchangeable lens 2 having no CLK terminal is attached to the camera has been described. According to the above configuration, when a lens that does not have a CLK terminal is attached to a camera that supports asynchronous communication, asynchronous communication is not necessary since the asynchronous communication is performed from the beginning. It is possible to shorten the time from when the image is taken to when the image can be taken. Further, the number of terminal members can be reduced on the lens side.

  As described above, in this embodiment, a camera capable of asynchronous communication detects the presence / absence of the CLK terminal of the attached lens and sets a communication method according to the lens. Specifically, asynchronous communication is performed from the beginning when a lens that does not have a CLK terminal is attached. On the other hand, when a lens having a CLK terminal is attached, synchronous communication is first performed, and after confirming that the lens is compatible with asynchronous communication, switching to asynchronous communication is performed. At this time, if the lens does not support asynchronous communication, synchronous communication is continued.

  As described above, according to the present embodiment, according to the present invention, the camera capable of asynchronous communication maintains the compatibility with the conventional lens, and the communication performance for the lens compatible with new communication. It becomes possible to improve.

<Modification of Example 1>
Example 1 above is a representative camera and interchangeable lens embodiment implementing the present invention, but does not represent all possible embodiments.

  The output terminal of the baud rate adjusting pulse Tmes output from the lens described in FIG. 7 (step 105) or the like is not necessarily limited to the CLK terminal described in the first embodiment, and may be a DOC terminal or a DOL terminal. In the first embodiment, the baud rate adjusting pulse Tmes output from the lens is a section from the falling edge of the signal output to the rising edge, but this is not necessarily limited to this form. If the communication circuit system between the camera and the interchangeable lens has switching between the open drain system and the CMOS system as in Patent Document 1, the circuit is switched to the CMOS system and then the baud rate adjusting pulse Tmes is applied to the lens. Is more preferable because delay rounding of the output waveform is reduced.

  In the first embodiment, the output timing of the baud rate adjusting pulse Tmes output by the lens is set immediately after the reception of DATA_C2, but this is also an example and there is no need to specifically limit it.

  In addition, the characteristics of electronic components such as a microcomputer and an oscillator used for the oscillation circuit often change depending on a change in temperature, and the oscillation frequency often changes within a certain range due to a temperature change. Therefore, it is more preferable to adjust the baud rate not only immediately before switching from synchronous communication to asynchronous communication described in (step 105) in FIG. 6 but also at other timings. Specifically, it is conceivable that the camera-side microcomputer 13 monitors the output of the temperature sensor 19 at an appropriate time interval during its operation, and adjusts the baud rate when a temperature change occurs more than a predetermined value.

<Example 2>
In the first embodiment, the method of detecting whether or not the signal line of the lens is connected to the camera side CLK terminal 15 by detecting the electrical connection of the terminal is described in order to check the presence or absence of the lens side CLK terminal. It can also be detected by other methods. For example, there is a method for detecting the mechanical operation of the camera-side CLK terminal 15. An example is shown in FIG.

  In FIG. 16, the camera-side CLK terminal 15 is biased by a spring (not shown) so that it slightly protrudes from the camera side. As shown in FIG. 16A, when there is no lens side terminal corresponding to the camera side CLK terminal 15, the camera side CLK terminal 15 remains protruding from the camera side. On the other hand, as shown in FIG. 16B, when there is a lens side CLK terminal 35 corresponding to the camera side CLK terminal 15, the camera side CLK terminal 15 is pushed into the camera side by the lens side CLK terminal 35.

  By detecting this difference by the detection switch 20 provided in the vicinity of the CLK terminal 15, it is possible to detect whether or not the lens signal line is connected to the CLK terminal 15.

  Even when this embodiment is applied, a camera capable of asynchronous communication can improve communication performance with respect to a lens compatible with new communication while maintaining compatibility with a conventional lens.

DESCRIPTION OF SYMBOLS 1 Camera 2 Interchangeable lens without CLK terminal 3 Interchangeable lens with CLK terminal 13 Camera side microcomputer 15 Camera side CLK terminal 16 Camera side DOC terminal 17 Camera side DOL terminal 21 Lens side microcomputer 26 Lens side DOC terminal 27 Lens side DOL Terminal 31 Lens side microcomputer 35 Lens side CLK terminal 36 Lens side DOC terminal 37 Lens side DOL terminal 42 Clock generation circuit 43 Communication control circuit

Claims (8)

An imaging device capable of mounting an interchangeable lens,
A first terminal and a second terminal for communicating with the mounted interchangeable lens;
A first communication mode in which a clock signal is output from the first terminal and communication is performed at the second terminal based on the clock signal, and communication is performed at the first terminal or the second terminal without using the clock signal. Control means capable of switching between the second communication mode and
Detecting means capable of detecting whether the mounted interchangeable lens has a first lens side terminal corresponding to the first terminal;
The control unit communicates in the second communication mode when the detection unit does not detect that the interchangeable lens has the first lens side terminal.   The control means performs communication in the first communication mode when the detecting means detects that the interchangeable lens has the first lens side terminal, and the communication causes the interchangeable lens to be in the second state. When it is determined that the communication mode corresponds to the second communication mode, the second communication mode is switched, and when it is determined that the interchangeable lens does not correspond to the second communication mode, the first communication mode is continued. The imaging device according to claim 1.   3. The detection unit according to claim 1, wherein the detection unit can detect whether or not an attached interchangeable lens has the first lens side terminal based on a voltage of the first terminal. 4. Imaging device.   When the detection unit does not detect that the interchangeable lens has the first lens side terminal, the control unit performs communication in the second communication mode at a preset communication speed, and the communication is performed. The imaging apparatus according to any one of claims 1 to 3, wherein if not established, the communication speed is changed and communication is performed again in the second communication mode. An imaging device capable of mounting an interchangeable lens,
A first terminal and a second terminal for communicating with the mounted interchangeable lens;
A first communication mode in which a clock signal is output from the first terminal and communication is performed at the second terminal based on the clock signal, and communication is performed at the first terminal or the second terminal without using the clock signal. Control means capable of switching between the second communication mode and
An electrical member capable of pulling down the first terminal;
Detecting means capable of detecting a potential state of the first terminal;
In the state where the interchangeable lens is mounted, the detection means detects the potential state of the first terminal,
The image pickup apparatus, wherein the control means communicates in the second communication mode when the potential of the first terminal is at a ground level.   When the control means performs communication in the first communication mode when the potential of the first terminal is not at a ground level, and determines that the interchangeable lens corresponds to the second communication mode by the communication. The imaging apparatus according to claim 5, wherein the imaging apparatus is switched to the second communication mode, and the first communication mode is continued when it is determined that the interchangeable lens does not correspond to the second communication mode. An interchangeable lens that can be attached to the imaging device according to any one of claims 1 to 6,
An interchangeable lens having no terminal corresponding to the first terminal. An imaging apparatus system having an imaging apparatus body and an interchangeable lens detachably attached to the imaging apparatus body, wherein the imaging apparatus body and the interchangeable lens can communicate with each other,
The imaging device includes a first terminal and a second terminal for communicating with an attached interchangeable lens, outputs a clock signal from the first terminal, and outputs the second signal based on the clock signal. It is possible to switch between a first communication mode that communicates with a terminal and a second communication mode that communicates with the first terminal or the second terminal without using a clock signal,
When the interchangeable lens has a terminal corresponding to the first terminal, the second communication is performed when the interchangeable lens corresponds to the second communication mode after performing communication in the first communication mode. Switch to the mode, if the interchangeable lens does not support the second communication mode, continue the first communication mode,
An image pickup apparatus system that performs communication in the second communication mode when the interchangeable lens does not have a terminal corresponding to the first terminal.

Images