JP2596535B2 - Camera system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera system, and more particularly, to a control means such as a microcomputer provided in a camera body, and detachable in and from the camera body. The present invention relates to a camera system having a circuit element provided in each of the camera accessories and whose operation is controlled by the control means.

2. Description of the Related Art In an interchangeable lens camera such as a single-lens reflex camera, various camera accessories such as a photographing lens and a flash device are exchangeable in a camera body. The operation of the projection lens and the flash device mounted on the camera body must be controlled by the camera body. Heretofore, conventionally, each camera accessory performs data communication with the camera body via an independent signal line or transmission mechanism, and the camera body is also provided with control means for each camera accessory separately. Was. Therefore, various kinds of data transmitted from each camera accessory are used only for controlling each camera accessory, and data transmitted from one camera accessory is used for controlling another camera accessory. However, precise control based on various kinds of data has not been possible.

[Object of the Invention] An object of the present invention is to provide a camera system capable of performing precise control based on more kinds of data than before using data transmitted from a camera accessory mounted on a camera body with a simple configuration. Is to provide.

[Constitution of the Invention] A camera system according to the present invention is a camera system comprising a camera body and a camera accessory detachable from the camera body, wherein a circuit element in the camera body which is provided in the camera body and performs a predetermined operation; A circuit element in the accessory that is provided in the camera accessory and performs a predetermined operation; a control unit that is provided in the camera body and controls the operation of the circuit element in the camera body and the circuit element in the accessory; In order to select a common data bus that performs serial data communication with the circuit elements in the accessory and a circuit element that performs data communication with the control means,
A circuit element selected via the chip select line by the control means, the chip element having independent chip select lines respectively connecting the control element and the circuit element in the camera body and the circuit element in the accessory; But,
The serial data communication is performed via the data bus.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a camera body, 2 is a release button,
The release button 2 is provided with a photometric switch S1 for instructing photometry when manually pushed down to the first stage, and a release switch S1 which is turned on when pushed down to the second stage and operates the shutter.

Reference numeral 3 denotes a mode changeover switch using a slide switch. P represents a program mode, S represents an exposure time priority automatic aperture mode, M represents a manual mode, and A represents an aperture priority exposure time automatic mode. Reference numeral 4 denotes a display device on which control exposure time, aperture value, and film sensitivity override data are displayed.

5 is an aperture value setting key, 6 is a shutter speed setting key, 7,
Reference numeral 8 denotes an up key and a down key for changing the aperture value F and the shutter speed SS. 9 is a counter display window,
The number of frames shot on the film is displayed.

Reference numeral 10 denotes an ISO mode key. When the ISO mode key is pressed, the ISO data used in the camera body 1 is displayed on the display unit 4.
Is displayed, and the up key 7 and the down key 8 can be used to change the ISO data.

11 is an override key. When this key is pressed, the override data is displayed on the display unit 4 and the up key is pressed.
7. By operating the down key 8, the override data can be changed. Reference numeral 13 denotes a film information display window provided on the back cover 13 of the camera body 1.

As shown in FIG. 2, the camera body 1 shown in FIG. 1 is provided with code reading contacts 15 and 16 for reading ISO data provided on the film container 14. The contact pieces 15 and 16 are formed on the outer peripheral surface of the film container 14 as shown in FIG. 6, for example, a plurality of contact pieces AT2 to AT6, FT8 and F which come into contact with the code electrodes 1 to 10 in two rows and six rows, respectively.
It has T9, FT10, RT11, RT12.

Each of the contact pieces AT2 to RT12 is fixed to an upright column 18 made of an insulating material in the camera body 1 with screws or the like.

In the camera body 1, as shown in FIG. 3, a back cover opening / closing detection switch 31 that is turned off when the back cover 33 of the camera is closed and turned on when the back cover 33 is opened, and a counter switch 34 that communicates with the film counter 34. Is provided. Counter switch
34 is opened and closed by a lever 36 operated by a cam 35, and is turned on when the count value of the film counter is between S and 1, and turned off when the count value is equal to or more than S.

FIG. 4 is a block diagram of the entire camera system to which the present invention is applied. (PO1) is a power-on reset circuit that outputs a power-on reset signal from the terminal (PR1) when a power supply battery (BAB) is mounted and power supply from the power supply line (VC) is resumed.

(MCB) is a microcomputer (hereinafter, referred to as a microcomputer) that controls the operation of the entire camera system. The operation of this microcomputer (MCB) is shown in FIG. 7, FIG. 8, FIG.
This is shown in the flowcharts of FIGS. 10 and 11. (S1)
Is a photometric switch, which is closed when the release button 2 is first depressed. (ISS) is a switch that is closed by pressing the ISO mode key (10), and (ORS) is a switch that is closed by pressing the override key (11). A switch (FSS) is closed by pressing an aperture value setting key (5), and a switch (SSS) is closed by pressing an exposure time key (6). (UPS) is a switch that is closed when the up key (7) is pressed, and (DOS) is a switch that is closed by pressing the down key (6). These switches are output terminals (O2), (O3), and (O3) of the microcomputer (MCB). (O4) and the input terminals (i1), (i2), and (i3) form a key matrix, and the closed switch is determined by the microcomputer (MCB).

This microcomputer (MCB) has a pin (O
2), (O3) and (O4) are “High”, and the line connected to the input terminal (i1) is passed through the AND circuit (AN1), OR circuit (OR1), and AND circuit (AN3). Interrupt terminal (it
A). Therefore, the photometric switch (S1), ISO
When the switch (ISS) or override switch (ORS) is closed, the terminal (itA) is interrupted and the microcomputer (M
CB) is activated.

(BMS) is a main switch. When this main switch (BMS) is opened, the output of the inverter (IN2) becomes “Low”, the microcomputer (MCB) stops operating, and the AND circuit (AN3) is turned off. Disabled, interrupt signal to pin (itA) is not input, microcomputer (MCB)
Is not invoked. If the power supply battery (BAB) is removed and power is not supplied from the line (VC), the AND circuit (AN3) is disabled and no interrupt is performed. Therefore, when the power supply battery (BAB) is not mounted or the main switch (BMS) is open, the microcomputer (MCB) remains in the operation stop state.

The switch (S2) is a switch that is closed at the second stage of pressing the release button (2). When the release button switch (S2) is closed, the output of the inverter (IN3) becomes “High”, and the AND circuit (AN2) and the OR circuit (OR
1), the interrupt signal is output to the terminal (it) via the AND circuit (AN3).
Enter A). When the interrupt signal is input, the shutter charge is completed, and if the production of exposure control data is completed, the operation immediately shifts to the exposure control operation. In addition, the interrupt by the release button switch (S2) is that while the microcomputer (MCB) is sending and receiving data to and from another circuit, the output of the OR circuit (OR3) becomes “High” and the AND circuit ( No interrupt is performed because AN2) is disabled.

The switch (RCS) is a back cover switch that is closed when the camera back cover (3) is opened as shown in FIG. 3 and is opened when the camera back cover (3) is closed. Therefore, when the back cover is closed, the output of the inverter (IN4) becomes “High”, a pulse is output from the one-shot circuit (OS1), the flip-flop (RF1) is set, and the terminal (itB) is connected. An interrupt signal is input. Then, the microcomputer (MCB) performs an operation when the back cover is closed, and when this operation is completed, a pulse is output from the terminal (O18) to reset the flip-flop (RF1) and enter an operation stop state.

(LE) is an interchangeable lens, connectors (CNF), (CNB
1) Data such as the aperture value, which is electrically connected to the camera body via the lens and is fixedly stored in the circuit (LEC) in the lens, is read into the microcomputer (MCB) in series via the interface circuit (BOL) It is. This operation is performed by the microcomputer (M
CB) sets the terminal (O5) to "High" and executes a serial input / output instruction, so that eight clock pulses are output from the serial clock pulse terminal (SCP). Then, data is input in series from the lens (LE) in synchronization with the clock pulse, and the data is read from the serial input terminal (SIN). By repeating this serial input command a plurality of times, all necessary data from the lens (LE) is read.

(CAD) is a code pattern circuit that outputs code pattern data provided on the film container (14), (E)
M) is a code plate that outputs data corresponding to the set exposure control mode. (SFC) is a counter switch that closes when the film counter is in the preliminary winding position and opens when the filming position is reached (corresponding to FIG. 32). It is.

(BUB) is a backup battery, (CIM) is ISO
This circuit stores data, reads data (CAD) from a film container, and reads mode data and a signal from a film counter switch (SFC). A specific example is shown in FIG. This circuit (CIM) is supplied with power from a backup battery (BUB) via a diode (D21) and also supplied from a main battery (BUB) via a diode (D20). (BCC) is a circuit that checks the output voltage of the backup battery (BUB). Power is supplied from the power supply line (VB) via the transistor (BT0), and the output of the backup battery (BUB) is equal to or more than a predetermined value. If it is, a "High" signal is output to the terminal (i20). (PO5) is a power-on reset circuit that outputs a reset signal when a backup battery (BUB) is attached. The reset signal from this circuit (PO5) is
It is sent only to the ISO data storage register in M), and the contents of this register are reset only when the backup battery (BUB) is installed. Terminals (O30), (O31),
(O32) is a terminal for controlling the operation mode of the circuit (CIM), and the circuit (CIM) performs an operation according to the output of this terminal. The OR circuit (OR50) is connected to this terminal (O3
0), (O31) and (O32) are input terminals, and the output terminal is connected to the input terminal of the OR circuit (OR3). Therefore,
If data is exchanged between the circuit (CIM) and the microcomputer (MCB), interruption to the terminal (itA) by the release switch (S2) is prohibited.

In FIG. 5, reference numeral (SD1) denotes a circuit which reads data input in series from the terminal (SOU) of the microcomputer (MCB) in synchronization with a clock pulse from the terminal (SCP). When the terminal (O30) becomes "High", the counter (LPC) that operates when "" becomes "High" counts a synchronization clock pulse, and outputs a latch pulse when eight clock pulses are counted. This latch pulse is sent to the register (LAC), and when this pulse is input, the data from the reading circuit (SDI) is latched. Register (LAC)
Is reset by a pulse from the power-on reset circuit (PO5) in FIG.

(DSC) is a data selector, and if the output of terminals (O31) and (O32) is "01", the register (LAC) from the input section (α1)
ISO data stored in the storage unit. If "10", input unit (α2)
Data on the film container from
The mode from 3) and the signal of the film counter switch are output respectively. If the outputs of the terminals (O31) and (O32) are "00", the data selector (DSC) does not output data. The serial data output circuit (SDO) is an OR circuit (OR52)
The data from the data selector (DSC) whose output becomes "High" is sequentially output to the terminal (SIN) based on the synchronization clock pulse.

The configuration of (CAD) and (EM) in FIG. 4 is shown in FIG.

In FIG. 6, a code pattern (1) is provided on the film container (14). Are conductive parts in any film container, and in this embodiment, the grounded electrode (COT) is in contact.
Are provided with a conduction / non-conduction pattern according to the data corresponding to the ISO sensitivity of the film in the film container (14), and this example is shown in Table 1.

The contact pieces (AT2) to (AT6) are in contact with these parts, respectively. These contact pieces are connected to the input terminal (α2) of the data selector (DSC) of FIG. 5 via a pull-up resistor and an inverter.
Has been entered. In the parts (1) to (4), a code pattern corresponding to the data of the number of photographed frames of the film (60) stored in the film container (14) is provided. The contact pieces (FT8), (FT9) and (FT10) are in contact with this part,
In this embodiment, since this data is not used, the data from the contacts (FT8), (FT9), and (FT10) are not input anywhere.

Exposure range data is provided in the part. This code is shown in Table 2.

The contact pieces (RT11) and (RT12) are in contact with the part (1), and a signal from this contact piece is input to the input terminal (α2) of the data selector (DSC) via the pull-up resistor and the inverter.

(MT1), (MT2), (CMT) are the code plates for data output in the exposure calculation mode. These code plates (MT1), (MT2),
The sliding member (VT) moves on (CMT) according to the mode setting by the mode changeover switch 3. When the sliding member (VT) is at the position (P), the data of “00” is in the program mode. When the sliding member (VT) is at the position of (S), the data is “10” in the exposure time priority mode (hereinafter referred to as S mode). If the data is located at the position (A), the aperture priority mode (hereinafter referred to as A mode) indicates “0”.
If the data of "1" is at the position of (M), the data of "11" is input in the input terminal (α) of the data selector (DSC) in the manual mode.
Input to 2). In addition, a signal input from the film counter switch (SFC) via the inverter (IN5) is also input to the input terminal (α2) of the data selector (DSC).

Referring again to FIG. 4, (FL) is a flash light emitting device, in which a power supply battery (BAF), a light emission and control circuit (FLC), and a main switch (FMS) are provided. The flash device (FL) is provided with a connector (CNF), which is electrically connected to the connector (CNB2) that attaches the flash device (FL) to the camera body and exchanges data with the control circuit (FCC). Operations such as transmission and reception and light emission amount control are performed.

(LMC) is a photometric circuit. The photometric output of this photometric circuit (LMC) is input to the analog input terminal (AN1) of the microcomputer, and the reference potential for DA conversion is input to the terminal (VRI). . A display circuit (DPC) drives a liquid crystal display (LDP) for data display and a display light emitting diode (FLD) for flash photography. The display circuit (DPC) takes in display data output from the terminal (SOU) while the terminal (O10) is at "High", and performs display based on this data. Details of this display unit will be described later with reference to FIG.
(RLC) is a release circuit which releases the lock of the exposure control mechanism based on a pulse from the terminal (O12).

(APC) is an aperture control circuit, and the aperture control circuit (A
The PC) reads the data of the number of steps that is sent from the terminal (SOU) while the terminal (O13) is “High”, and stops the aperture of the camera when the actual number of steps matches the read data. Then, the aperture is determined. (TIC) is an exposure time control circuit that reads the exposure time control data output from the terminal (SOU) while the terminal (O14) is “High” and reads the data from the time when the count switch (S3) is closed. The shutter closing operation is started after a lapse of time corresponding to the data. Further, the terminal (TIE) becomes “High” when the release signal (RLS) is output, and starts the shutter closing operation for a certain period of time (for example, 50 msec).
It will be “Low” after elapse.

Next, the operation of this system will be described based on the flowchart of FIG. When power supply from the terminal (VC) starts, power supply to the microcomputer (MCB) starts and the microcomputer (MC
B) performs an initial reset operation. The flip-flop (RF1) is reset by the power-on reset signal (PR1), and the display circuit (DPC) supplied from the terminal (VC) is also reset.

The microcomputer (MCB) starts with the terminal (O
1)-(O4) is set to “High”, and terminals (O5)-(O18) are set to “L”.
ow ". The terminal (O31) is set to" High "and the terminal (O3
0) and (O32) are set to "Low", and the serial input / output operation is performed after a certain period of time required for the vibration due to battery attachment to subside and the contact between the contact piece and the film container to stabilize has elapsed. Then, the data on the film container from the detection unit (CAD) is read into the register IOR via the circuit (CIM), and this data is set in the register CAR. Register C
Table 4 shows how to set the data in the AR.

Next, the terminal (O32) is set to “High” to perform a serial input / output operation, and the ISO data stored in the register (LAC) is read. The read data is set in the register MER. Next, the terminal (O31) is also set to "High" to read the mode data and the counter switch data, and set this data in the register MOR. And then the input terminal (i20)
Is "High", and if "High", the output voltage of the backup battery (BUB) is sufficient.
Determine whether the data read from the register (LAC) is normal. In this determination, if all bits are not "0", it is sufficient to determine that the bit is normal. If the backup battery (BUB) is normal and the data from the register (LAC) is normal, the data (MER) read from the register (LAC) is set in the register SVR, and the process proceeds to step # 3. .

If the output voltage of the backup battery (BUB) is equal to or lower than the predetermined value in step # 1 or if normal data is not read from the register (LAC) in step # 2, the process proceeds to step # 4. Transition. In step # 4, it is determined whether or not the data from the film container has been read by determining the contents of the register CAR. If the data has been read, the ISO data based on the data from the film container is stored in the register SVR. If it is not set, the fixed data Svn (for example, ISO100Sv =
5) is set in the register SVR. Next, the content of the register SVR is set to the input / output register IOR, and the terminal (O30) is set to “Hi”.
gh "to perform serial I / O operation, and this is sent to the contents of register SVR and storage register (LAC). Next, when fixed data is set, bits MDR0 and MDR7 are set to“ 1 ”. The remaining bits are set to “0.” Here, the register MDR is a register in which data indicating the display mode is set, and the meaning of each bit is as follows. “0” when neither symbol nor SS symbol is displayed, “1” when ISO or SS symbol is displayed
become.

MDR1 is “1” when displaying the exposure time on the display, ISO
It is "0" when displaying data.

When displaying override data, MDR2 and MDR3 are set to “01” if the override data is on the + side, “10” if the override data is on the negative side, and “11” if the override data is 0 and the override data is displayed. When not displayed, it is "00". Therefore, if MDR2,3 is "00", no indication about override is made and "01"
If so, "+" is displayed before the override symbol "+/-" and the override data. If "10", "-" is displayed before the symbol "+/-" and the override data. If it is "11", the symbol "+/-" is displayed. At this time, 0 is displayed for the override data, and neither "+" nor "-" is displayed before the data. In addition,
Even if the signal “+/-” indicates the exposure control value,
Displayed if MDR2,3 is "01", "10".

MDR4 is "1" when displaying the F value, and "0" when not displaying the F value. Therefore, when "1", "F" is displayed, and when "0", "F" is not displayed. MDR5, MDR
6 is a light emitting diode (F
A signal indicating the display mode of (LD) is set. When set to “00”, the flash unit is not attached to the camera body (FL
D) is off. "01" indicates that the flash unit is in a powered state is mounted, blinks 2H _2. "Ten"
Indicates that the flash device is fully charged, the light emitting diode (FLD) lights up, and "11"
Indicates that dimming is complete, and the light emitting diode (FL
D) is flashing 8H _2. MDR7 the entire liquid crystal display unit when it is "1" flashing 2H _2, when the "0" lights.

Next, the contents of register SVR, data B for blank display
The contents of the LD and the register MDR are sent to the display unit (DPC), and the terminals (O2) and (O4) are set to "Low" to enable interruption to the terminals (itA) and (itB), and wait for 10 seconds. Therefore, when the power supply battery (BAB) of the microcomputer (MCB) is installed, the storage circuit (LA) supplied by the backup battery (BUB)
C) or the backup battery (BU
If the output of B) is not normal and the ISO data based on the data on the film container is not read and fixed ISO data is set, this data flashes for 10 seconds and a warning is displayed. Done. Further, when it is determined by the bit 2 of the register MOR that the film counter switch (CFC) is open, the terminals (O2) and (O4)
To “Low”. Therefore, an interrupt signal is input to the terminal (itA) only when the ISO switch (ISS) is closed, so that the exposure control operation is not started even if the release button is operated, and the release lock state is established. To get out of this state, operate the ISO switch or wait 10 seconds. When it is determined that the film counter switch (CFS) is closed, the possibility that the film is mounted is low, and the release lock is not performed, and the control waits for 10 seconds.

After 10 seconds, the terminals (O2) and (O4) are set to “High”
Then, the process proceeds to the step # 3, and data for lighting and displaying the ISO data is sent to the display unit (DPC) to be in the “HALT” state. When normal ISO data is read from the register (LAC), this data is set, and the process immediately proceeds to step # 3 to display the ISO light. Even if the register (LAC) is not normal, when normal data is read from the film container, ISO is lit and the release lock is not activated.

FIG. 8 shows the operation when the back cover is closed and an interrupt signal is input to the terminal (itB). First, a certain time (for example, 0.5 sec) elapses after the back cover is closed.
This is because the film container vibrates immediately after the back cover is closed, and the contact between the film container (14) and the lighting (15), (16) is not stable. Next, terminals (O2), (O
3), (O4) is “High”, terminals (O1), (O5) to (O1
8), (O30) and (O32) are set to “Low”, and the terminal (O3
Set 1) to “High” to perform serial input / output operation. Thus, data from the film container is read.
Next, based on the read data, it is determined whether or not data is provided on the film container.If provided, ISO data based on this data is set in the register SVR, and the data is stored on the film container. If no data is provided, the contents of the register SVR are left as before.

Next, the bit MDR0 is set to “1”, the remaining bits MDR1 to MDR7 are set to “0”, and the contents of the register SVR, the blank data BLD,
The set ISO data is displayed by sending the contents of the register MDR to the display unit (DPC). Then, the terminal (O18) generates a pulse to reset the flip-flop (RF1),
Waiting for 5 seconds to enable interrupts to the terminals (itA) and (itB), the display is turned off and the state becomes "HALT" in the same manner as the operation from step # 3 in FIG.

Here, a specific example of the (CAR) presence determination of # 4 and # 8 will be described with reference to FIG. As shown in Table 1, in the case of a film container provided with a code pattern, at least one of the parts is always a conductive part. Therefore, if "1" is read into either bit CAR4 or CAR3 of register CAR, data is set from the code pattern on the assumption that the container provided with the code pattern is mounted.

On the other hand, if both bits are “0”, it means that the film container without the code pattern is mounted or the film container is not mounted, and in this case, it is based on the contents of the register CAR. No data is set.

Next, a specific example of the operation for setting the film sensitivity in steps # 7 and # 10 will be described with reference to FIG. First, 16 _H ( _H indicates a hexadecimal number) is set in the register SVR.

Here, the registers SVR1 and SVR2 are 8 bits, and each bit is weighted from the upper bit by 16, 8, 4, 2, 1, 1/2, 1/4, 1/8. And the film sensitivity is the apex value
It changes in 1 / 3Ev units. Therefore, if the number of parts of the sensitivity of the film set in the camera is 1/3, it is approximately 1/4, and if it is 2/3, it is approximately 3/4 (= 1/4 + 1/2). Therefore, in step # 1, 16 bits set in register SVR1
_H is Is equivalent to

Next, first, the bits CAR4 and CAR5 of the register CAR are set to “11”.
If it is “08 _H ”, “10” is “04 _H ”, “01” is “02”
_H ”is added to the contents of the register SVR1. Therefore, if the bit of the decimal part is“ 11 ”, Sv = 1 is added to“ 1E _H ”, and the decimal part is 3/4. 10 "for Sv = 1 /
2 is added to “1A _H ” to reduce the decimal part to 1/4. If the bit of the decimal part is “01”, Sv = 1/4 is added to “18 _H ” to set the decimal part to 0.

Next, if bit CAR2 of register CAR is 1, Sv = 4, CAR1
Is added to the contents of the register SVR1 if Sv = 2 and CAR0 is 1 if Sv = 1. The above operation will be described with an example in which a film container of ISO 400 is mounted on a camera. In this case, as shown in Table 1, the portion indicated by, is a conducting portion. In the register CAR, the bits CAR3 and CAR2 are "1", and the CAR4, CAR1 and CAR0 are "0". Therefore, 22 _H is added to the register SVR1 to be 38 _H. This data is 4 + 2 + 1 = 7 according to the definition of the weight of each bit, and the apex value Sv = 7 in ISO400.

Next, the operation of FIG. 4 based on the flowchart of FIGS. 11-1, 2, 3, and 4 will be described. When the power supply battery (BAB) is installed with the main switch (BMS) closed,
When one of the photometric switch (S1), ISO switch (ISS), and override switch (ORS) is closed, an interrupt signal is input to the terminal (itA) via the AND circuit (AN3).
The operation from step 11 is started. First, the flag CCF
Is determined whether or not the content of “1” is “1”. This flag CCF is “1” when exposure control data is calculated, and is “0” when exposure control data is not calculated. The operation when an interrupt signal is input to the terminal (itA) in a state where the calculated control value has been calculated will be described later.

When the flag CCF is “0”, the terminal (O1) is set to “High” next. As a result, the transistor (BT0) becomes conductive, and power supply starts from the line (VB). Further, the AND circuit (AN1) is disabled, the AND circuit (AN2) is activated, and the signal from the release switch (S2) can be input to the terminal (itA) as an interrupt signal. Next, by setting the terminals (O3) and (O4) to "Low", only the terminal (O2) is set to "High" and it is determined whether or not the terminal (i1) is "High". If the terminal (i1) is “High”, the photometric switch (S
When 1) was closed, the interruption was made,
Set the flag LMF to “1” and set the terminal (O2) to “Low”.
If the switch (SI) is open and the terminal (i1) is determined to be "Low" in step # 13, then only (O3) is set to "High" and the terminal (i1) is set to "High". " If "High" at this time, ISO switch (ISS)
When the flag ISF is set to "1" and the terminal (i1) is "Low", the interrupt is performed by the override switch (ORS), and the flag ORF is set to "1". To Then, the terminal (O3) is set to "Low", and the process proceeds to step # 14.

In the step # 14, the terminal (O5) is set to “High”. Then, data from the lens (LE) is read by performing the serial input / output operation a plurality of times (a predetermined number of times), and the read data is sequentially set in a plurality of registers LDR. When this operation is completed, the terminal (O5) is set to “Low”, and the terminal (O31),
(O32) is set to “High”. After this operation, a serial input / output operation is performed to read the mode signal applied from the code plate EM and the signal from the counter switch (SFC), set the register MOR, and set the terminals (O31) and (O32). Set to “Low”. The mode data is set to bits MOR0 and MOR1, and the signal of the counter switch (SFC) is set to MOR2. Thus, the state of the film counter and the signal of the exposure control mode are taken into the register MOR.

Next, the terminal (O9) is set to “High” and the terminal (O8) is
Output pulse of μsec width. And I / O register I
After data of “00H” is set in OR, a serial input / output operation is performed. Then, the flash device (F
L), and this data is stored in register FDR
Is set to Then, the terminal (O9) is set to “Low” and # 15
Go to step.

In step # 15, the output representing the photometric result of the subject obtained from the photometric circuit (LMC) is subjected to AD conversion.
Perform an operation of (Bv−Avo−Avc) + Avo + Avc = Bv to remove terms of the open aperture value Avo and the open metering error Avc included in the D-converted data based on the data from the lens (LE). To calculate data of subject brightness.

Then, the calculation of Bv + (SVR) = Ev is performed, and the exposure value Ev is calculated.

Next, it is determined whether or not the contents of the bits MDR2 and MDR3 of the register MDR are “01”. Is subtracted from the exposure value Ev to calculate the Ev value. If the contents of MDR2 and MDR3 are not "01", it is next determined whether or not it is "10". If "10", it means that the -side override has been performed, and the -side override data is set. Add the contents of register ORR2 to exposure value Ev
Calculate the Ev value.

Upon completion of the above operation, the flow shifts to step # 16, and thereafter, an operation of calculating exposure control data is performed. In the step # 16, it is determined whether or not the mode is the P mode. If the mode is the P mode, the calculation for the steady light photographing and the calculation for the flash light photographing in the P mode are performed, and the flag DCF1 is set to "0". Move to Here, the flag DCF1 is "1" when the set aperture value or the set exposure time is changed, and becomes "0" when there is no change. In the P mode, neither data change is accepted. is 0"
Becomes

If it is determined in step # 16 that the mode is not the P mode, the process proceeds to step # 19 to determine whether the mode is the A mode. In the case of the A mode, a change in the set aperture value is accepted, so that this data first performs a change operation. First, the terminal (O
2) Set "High" to determine whether the terminal (i2) is "High". If the terminal (i2) is "High", the fixed aperture switch (FSS) is closed. Then, the terminal (i
It is determined whether or not 3) is “High”. If “High”, the up switch (UPS) is closed. In this case, the terminal (O2) is set to "Low" and the data change operation to the small aperture side is performed. That is, it is first determined whether or not the content of the register AVR3 in which the set aperture value data is set is on the open side of the open aperture value data Avo from the lens (LE) (this data is sent from the lens ROM). I do. If the data is on the open side of the open aperture value Avo (this occurs when the lens is replaced), the content of the register AVR3 is set to Avo, and the routine proceeds to step # 20.
If the contents of register AVR3 are not opener than Avo, then
It is determined whether or not vo is equal. If they are equal, data dAv from the lens (LE) is added. If they are not equal, 1/2 is added to the contents of register AVR3. Determine whether the value is larger than the maximum aperture value data Avm, and if it is larger, register AV
The maximum aperture value Avm is set to R3, and the process proceeds to step # 20. If not, the process directly proceeds to step # 20. The maximum aperture value data Avm is also sent from the lens ROM.

Here, the data dAv will be described. There are various values for the open aperture value of interchangeable lenses, and 0.5 Ev units (Avo = 0.5, 1.0,
Some are 1.5, 2.0 ...) and some are not in 0.5Ev units (for example, F2.5 (Av = 2.64), F3.5 (Av
= 3.61), F1.8 (Av = 1.7), etc.). By the way, the aperture value set on the camera side is a series of 0.5 Ev unit except for the open aperture value. Therefore, if the aperture is not in 0.5Ev units, the aperture value changes from the open aperture to the next set aperture by a value dAv smaller than 0.5Ev and becomes a value in 0.5Ev units. It changes. Therefore, F2.5
For a lens of dAv = 0.36, for a lens of F3.5 dAv = 0.39, F
For a 1.8 lens, dAv = 0.3. This data dAv
Is also sent from the lens ROM.

When the terminal (O2) is “High”, the terminal (i3)
If it is determined that the up switch (UPS) is not closed, not "igh", the terminal (O2) is set to "Low" and the terminal (O3)
It is determined whether or not the down switch (DOS) is closed from the state of the terminal (i3) with only "High". When it is determined that the down switch (DOS) is closed, the terminal (O3) is set to “Low”, and the content of the register AVR3 is set to 1 /
2 is subtracted, and it is determined whether or not the result of the subtraction is on the open side from the open aperture value Avo. If the value is on the open side, the open aperture value Avo is set in the register AVR3, and # 20
Go to step.

In step # 20, "1" is set in the flag DF1 to indicate that the setting data has been changed, and the process proceeds to step # 21. On the other hand, if the aperture switch (FSS) is not closed, or if both the up switch (UPS) and the down switch (DOS) are not closed, no data is changed, and the flag DCF1 is set in step # 23. Sets "0" and proceeds to the step # 21. In the step # 21, the calculation for the steady light photographing in the A mode is performed. Then, in the step # 22, the calculation for the flash light photographing in the A mode is performed, and then the process proceeds to the step # 24.

If it is determined in step # 19 that the mode is not the A mode, it is determined in step # 25 whether the mode is the S mode. When it is determined that the mode is the S mode, it is next determined in steps # 25 and # 26 whether or not the exposure time switch (SSS) is closed from the state of the terminal (i2). When it is determined that the exposure time switch (SSS) is not closed,
At step # 28, the flag DCF1 is set to "0", and the routine proceeds to step # 29. On the other hand, if it is determined in step # 27 that the exposure time switch (SSS) is closed, then it is determined whether the up switch (UPS) is closed. And it is # 3 that the up switch (UPS) is closed.
If it is determined in step 0, 1 is added to the contents of the register TVR3 in which the set exposure time data is set. It is determined in step # 31 whether or not the addition result is larger than the shortest exposure time data Tvm.
The flag DCF1 is set to "3", and if it is not large, the flag DCF1 is set to "1" in step # 32, and the process proceeds to step # 29.

Up switch (UPS) not closed # 3
If it is determined in step 0, then the down switch (DO
It is determined in step # 33 whether or not S) is closed. If the down switch (DOS) is closed, 1 is subtracted from the contents of the register TVR3 in step # 34, and it is determined whether or not the result of the subtraction is longer than the longest exposure time Tvo. And for a long time Tvo
Is set in the register TVR3, and if it is not a long time, the flag DCF1 is set to "1" and the process proceeds to step # 29.

When the exposure time switch (SSS) is not closed,
Or, if both the up switch (UPS) and down switch (DOS) are not closed, the flag D
CF1 is set to “0”, and the process proceeds to step # 29. # 2
In the step 9, the calculation for the steady light photographing in the S mode is performed, then the calculation for the flash photographing in the S mode is performed, and the process proceeds to the step # 18.

If it is determined in step # 25 that the mode is not the S mode, the mode is the M mode. In this case, both the aperture value data and the exposure time data can be changed. After the change, the calculation for the steady light photographing in the M mode and the calculation for the flash light photographing in the M mode are performed, and the process proceeds to the step # 18.

In step # 18, since the calculation of the exposure control data has been completed, it is possible to shift to the exposure control operation, and the flag
Set “1” to CCF. Then, an interrupt operation by an interrupt signal to the terminals (itA) and (itB) is enabled. Next, it is determined whether or not the currently powered flash device is mounted on the basis of data from the flash device (FL). If there is no mounted signal, the bits MDR5 and MDR6 of the register MDR are set to “00” to # 35. Go to step. If there is a mounting signal, then it is determined whether or not the dimming operation completion signal (hereinafter referred to as FDC signal) is input. If the FDC signal is input, “11” is set in bits MDR5 and MDR6 of register MDR. Set and move to step # 35. On the other hand, if the FDC signal is not input, it is determined whether or not the next charge completion signal is input. If the charge completion signal is input, “10” is input to the MDRs 5 and 6; 01 "is set.

In step # 35, the terminal (O9) is set to "High", and data is transferred from the camera to the flash device (FL). In step # 36, a pulse having a width of 100 μsec is output to the terminal (O8). Next, the ISO data set in the register SVR is set in the input / output register IOR, and the contents are output from the analog signal output terminal (ANO) via the DA converter. Subsequently, the serial input / output operation is performed to send the ISO data to the flash device.

Next, the contents of register AVR2, in which the aperture value data for flash photography is set, are set in register IOR and sent to the flash device, and the contents of register TVR2, in which exposure time data for flash photography is set, are set in register IOR. And send it to the flash device. Next, of the data from the lens (LE), the content of the register LDRf in which the focal length data is set is set in the register IOR, sent to the flash device, and the terminal (O9) is set to "Low". The above is the data transfer operation to the flash device. Based on these data, the flash device performs operations such as displaying an interlocking range and automatically setting an irradiation angle.

Next, in step # 40, it is determined whether or not the flag ISF is "1". If "1", it means that the ISO switch is closed, and the process proceeds to step # 43. On the other hand, “0”
Then, it is determined whether or not the flag ORF is "1" in a step # 41. And if “1”, override switch (OR
This is the case where S) is closed, and the process proceeds to step # 44. On the other hand, if it is “0”, bit M of register MOR
The contents of OR2 are discriminated, and if "0", the film counter switch (SFC) is closed and the film counter has not reached position 1 (the position of the photographable film frame), and the process proceeds to step # 52. Transition. In step # 42,
When it is determined that the bit MOR2 of the register MOR is “1” and the film counter switch (SFC) is open, the process proceeds to step # 46, in which case the bit is set in a mode for displaying the exposure control value. If MDR2,3 is "11", it is set to "00" and MDR1 and MDR4 are set to "1". As a result, the symbol +/- is not displayed unless the override is performed,
Further, the symbols of F and SS are displayed on the display device LDP.

Next, it is determined whether or not the charging completion signal is input. If the charging completion signal is input from the flash device (FL) to the microcomputer (MCB), the exposure time for flash photography (contents of the register TVR2) and the aperture are determined. The value (contents of the register AVR2) is sent in series to the display unit (DPC), and the exposure time (contents of the register TVR1) and the aperture value (the content of the register AVR1) for steady light photography if the charge completion signal is not input Are serially sent to the display unit (DPC), and the flow shifts to the step # 49 in FIG. 11-4.

If it is determined in step # 40 that the ISO switch (ISS) is closed, the process proceeds to step # 43.

When the process proceeds to step # 43, only the terminal (O2) is set to “Hig
In step # 50, it is determined whether the up switch (UPS) is closed. Then, the up switch (UPS) is determined.
Is closed, it is then determined in step # 51 whether the manually set minority part of the ISO data is 1/4. If it is 1/4, 1/2 is added, and if it is not 1/4, data obtained by adding 1/4 is set in the register SVR2. Therefore, if the decimal part is 0,
If it is 1/4, 1/4, it becomes 3/4, and if it is 3/4, it becomes 0. That is, as described above, 1/3 = 1/4, 2/3 = 3/4, and 0 = 0. And
Determine whether the contents of the register SVR2 is larger than the maximum ISO data Svm, and if it is larger than Svm, set Svm to the register SV.
Set to R2, if it is not large, leave it as it is, and proceed to step # 52.

If it is determined in step # 50 that the up switch (UPS) is not closed, the process proceeds to steps # 53 and # 54, where only the terminal (O3) is set to "High", and the down switch (DOS) is set in # 55. Is determined whether or not is closed. Then, if the down switch (DOS) is closed and the decimal part of the data that is manually set is 3/4, subtract 1/2, and 3/4
If not, subtract 1/4. That is, if it is 3/4, it is 1/4, if it is 1/4, it is 0, and if it is 0, it is 3/4. Then, it is determined whether or not the content of the register SVR is smaller than the minimum ISO data Svo,
If it is smaller, Svo is set to SVR2. If it is not smaller, the process proceeds to step # 52.

If it is determined in step # 55 that the down switch (DOS) is not closed, the process proceeds to step # 52 while keeping the contents of the register SVR.

In the step # 52, the flag DCF2 is set to "1", the bit MDR0 is set to "1", the bits MDR1, MDR4, and MDR7 are set to "0", the content of the register SVR is set to the register IOR, and the terminal (O30)
To “High” to perform serial input / output operation. As a result, the newly set ISO data is fixedly stored in the storage register (LAC) (FIG. 5) in the circuit (CIM). Subsequently, the ISO data and the data for turning off the aperture value display unit are sent to the display circuit (DPC), and the process proceeds to step # 49.

If it is determined in step # 41 that the flag ORF is "1" and the override switch (ORS) is closed, the flow proceeds to step # 44. That is, step # 57
First, it is determined whether or not the up switch (UPS) is closed. If the up switch (UPS) is closed, MDR2 and MDR3 are set to “01” and the contents of the register ORR1 are set to 1/2.
Is added. Then, it is determined whether or not the content of the register ORR1 exceeds the maximum value ODm. If it does, the ODm is set in the register ORR1, and if not, the flag DCF is set to “1” in step # 58. To step # 60.

When it is determined in step # 57 that the up switch (UPS) is not closed, the process proceeds to step # 61, in which only the terminal (O3) is set to "High", and in # 62, the down switch (DOS) is set. Is determined whether or not is closed. If the down switch (DOS) is closed, register ORR
Add 1/2 to the contents of 2, and if it exceeds the maximum value ODm, set ODm in the register ORR2. If not, set "1" to the flag DCF2 and go to step # 60. I do.

If the down switch (DOS) is not closed in step # 62, the flag DCF2 is set to "1" while the MDR2 and MDR3 and the registers ORR1 and 2 are left as they are, and the process proceeds to step # 60 in FIG. 11-4. Transition.

In step # 60, it is determined whether the bits MDR2 and MDR3 of the register MDR are “00”, and if “00”, “1” is displayed for display.
MDR0, MDR1, MDR4, and MDR7 are set to "0".
Therefore, in this case, the symbol +
Only the /-symbol is displayed.

Next, the blank data (BLD) is output to the register (IOR) and further sent to the display unit (DPC) so that the numerical display unit of ISO or SS is turned off. Then, the contents of MDR2 and MDR3 are changed to “01”. If it is "+", the contents of the register ORR1 are sent to the display unit (DPC) if it is not "01" because the register ORR1 is not "01", and the process proceeds to step # 49. Next, in step # 49, register MDR
To the display (DPC) and set the terminal (O11) to “High”
The display by the light emitting diode (FLD) of the display unit (DPC) is enabled.

Next, it is determined whether or not one of the flags DCF1 and DCF2 is “1”. If “1”, the data is changed, and in this case, the data change is performed at a high speed. Wait for a certain period of time in order to prevent the situation, and then proceed to step # 65. On the other hand, if the flags DCF1 and DCF2 are both “0”, the process immediately proceeds to step # 65. In step # 65, the terminals (O2), (O3) and (O4) are set to "High" and whether (i1), (i2) and (i3) are set to "High", that is, the key switch is set to one. Determine if any of them are closed. If any one is closed, set the data for 5 seconds in the internal counter ICO,
Determine whether the main switch (BMS) is closed. If the main switch (BMS) is closed, (O2) and (O4) are set to “Low” and the switch (ISS)
Is determined whether or not is closed. And (IS
If S) is closed, the flag ISF is set to "1", the ORF and LMF are set to "0", and the process returns to the step # 14. If (ISS) is not closed, it is determined whether the switch (ORS) is closed, and if it is, ORF is set to “1”, LMF and ISF are set to “0”, and #
Return to step 14. If the switches (ISS) and (ORS) are both open, the flag LMF is set to "1" and the process returns to step # 14. Therefore, the exposure time and the aperture value are displayed for 5 seconds when none of the switches are closed.

If all the key switches are not closed, it is determined whether or not the content of the internal counter ICO is "0", and if it is "0", the flow proceeds to step # 67. On the other hand, if it is not "0", it is determined whether or not the reset switch (S4) is closed, and if not, the state of the main switch (BMS) is determined, and # 66 to # 14 are determined.
Return to step.

When 5 seconds elapse after all the key switches are opened, when the reset switch (S4) is closed, or when the main switch (BMS) is opened, the process proceeds to step # 67 and the terminal (O1), (O5) to (O18) are set to “Low”, the flags CCF, LMF, ISF, and ORF are set to “0”, and the interrupt pin (itA)
The interrupt by (itB) is enabled, the display is turned off in the same manner as the operation from the seventh step # 3, and the HALT state is set.

When the release switch (S2) is closed with the calculation of the exposure control value completed and the flag CCF set to "1", the terminal (itA)
Is accepted, and the process proceeds to step # 70.
In step # 70, the terminal (O9) is set to "High", and a pulse of 50 μsec width is output from the terminal (O8) to read data from the flash device. Then, it is determined whether or not the charging completion signal is input. If the charging completion signal is input, the content of the register PVR2 in which the aperture value for flash photography is set is sent to the aperture control circuit (APC), and the charging completion signal is output. Is input to the aperture control circuit (APC), the contents of the register PVR1 in which the aperture value for the constant light imaging is set. Next, it is determined again whether or not the charging completion signal has been input, and if it has been input, the register TVR in which the exposure time for flash photography is set is set.
2. If the input is not input, the contents of the register TVR1 in which the exposure time for steady light photography is set are stored in the exposure time control circuit (TI
Send to C).

Next, the terminal (O9) is set to “High” and the flash device (F
By sending a 150 μsec pulse from the terminal (O8) to L), the flash device determines that the exposure control operation has started. Then, the terminal (O11) is set to "Low" to turn off the light emitting diode (FLD) so that the light emission display is not performed during the exposure control. Next, a pulse is output from the terminal (O12), and the release circuit (RLC) performs the release operation of the shutter to start the exposure control operation. Then, it waits for the reset switch (S4), which operates when the shutter curtain is opened, to complete the exposure control operation, and then closes (S
4) When terminals are closed, terminals (O2), (O3) and (O4)
igh ", the flow shifts to the step # 67, and the same operation as described above is performed to enter the HALT state.

FIG. 12 is a specific example of the display circuit of FIG. When the terminal (CDP) becomes “High”, the synchronization clock pulse (SC
Each time eight P) are input, terminals (1), (2), (
The latch pulse is output from the latch control circuit (LAC) to 3). The data read by the serial input register (SIR) is sequentially stored in the registers (REG1), (REG2),
(REG3). Therefore, the register (REG1) contains the exposure time or ISO numerical data, (REG2) the aperture value or override numerical data, and (REG3) the display mode data, that is, the contents of the register MDR in the microcomputer (MCB). Is set, and the output of terminals (e0) to (e7) is
Corresponds to R bits MDR0 to MDR7.

The decoder (DE1) converts the output of the register (REG1) into a value for displaying the exposure time, and (DE2) converts the value into a value for displaying the ISO data. Then, the data selector (DS1) is connected to the terminal (e
If 1) is “High”, that is, the exposure time display mode, the decoder (D
If the data from E1) is "Low", that is, if the display mode is the ISO display mode, the data from decode (DE2) is transmitted. The decoder (DE3) converts the output of the register (REG2) into a value for displaying an aperture value, and the decoder (DE4) converts the output for displaying an override. The data select (DS2) is connected to the terminal (e
4) If "High", that is, the aperture value display mode, the decoder (DE
The data from 3) is output as "Low", that is, data from the decoder (DE4) unless the aperture value display mode. The decoder (DE5) is connected to the terminals (e0) to (e) of the register (REG3).
This is a decoder that converts the data from 4) into data for signal display.

Timing signal output circuit (TIC) is 8Hz at terminal (j1)
(J2) outputs a 2Hz clock pulse, and further outputs a common signal output circuit (COD) and a segment signal output circuit (SE
Send the timing signal to D). The segment signal output circuit (SED) outputs data select (DS1), (DS
2) A display signal based on the data from the decoder (DE5) is output to perform liquid crystal display. If the terminal (e7) of the register (REG3) is “High”, the AND circuit (G
2) Clock pulse is output from 1) and the liquid crystal display is 2Hz
Flashes.

The signals from the terminals (e5) and (e6) of the register (REG3) and the 8 Hz and 2 Hz clock pulses from (j1) and (j2) are sent to the drive circuit (LDC), and the terminal (DPE) is set to “High”. "", A drive signal according to the state of the flash is output to the terminal (FLD).

FIG. 13 shows a specific example of display in the embodiment of the present invention. FIG. 13 (a) shows an example of a display state when the exposure time is set. The first display section, which is also used for displaying the shutter speed and the film sensitivity, has a display indicating the shutter speed of 1/2000 sec. At the same time as the second
The aperture value F5.6 is displayed on the display section. On the other hand, FIG. 13 (b) shows an example of a display state at the time of setting the film sensitivity.
The film speed ISO400 is displayed on the first display, and nothing is displayed on the second display.

Modified Example In this embodiment, data on the film container is read out after a certain period of time after the back cover is closed, and this data is stored.However, such a storage circuit is not provided, and exposure calculation is performed. When performing, the present invention can be applied to a camera of a type that always reads data on a film container. In this case, reading from the film container, exposure calculation, and exposure control may be prohibited for a certain period of time after the back cover is closed.

[Effects of the Invention] As described above, the present invention provides a camera system including a camera body and a camera accessory detachably mounted on the camera body, a circuit element provided in the camera body and performing a predetermined operation, A circuit element in the accessory for performing a predetermined operation provided in the camera accessory, a control means provided in the camera body for controlling the operation of the circuit element in the camera body and the circuit element in the accessory, a control means and a circuit element in the camera body And a common data bus for performing data communication with the circuit elements in the accessory, and a circuit between the control means and the circuit elements in the camera body and the accessory in order to select a circuit element for performing data communication with the control means. And a circuit element selected by the control means via the chip select line and the control circuit. Means for communicating data via the data bus.
With this configuration, it is possible to concentrate data on a single control means provided in the camera body, thereby enabling various accessories to be precisely controlled based on various types of data. Data communication can be performed accurately with a very simple configuration. Further, the selected circuit element is free except during the selected data communication.

Further, since the chip select lines are provided independently, there is no danger of data interference.

[Brief description of the drawings]

1 is a perspective view showing the appearance of a camera to which the present invention is applied, FIG. 2 is a view showing the inside of the camera of FIG. 1, FIG. 3 is a film counter and a counter switch, a back cover and a back cover open / close detection. FIG. 4 is a block diagram showing an embodiment of a camera system to which the present invention is applied, FIG. 5 is a block diagram showing a main part of the camera system of FIG. 4, and FIG. 7 is a perspective view showing a portion for reading data from the film container, FIGS. 7 to 11-1 to 11-4 are flowcharts showing the operation of the camera system shown in FIG. 4, and FIG. 12 shows another embodiment. FIGS. 13 (a) and 13 (b) are diagrams showing examples of display on the display device. 10: ISO mode key, 14: Film container, MCB: Microcomputer, CAD: Film container code pattern output circuit, DSC: Data selector, DPC: Display, 33: Back cover, LMC: Photometry circuit.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masatake Niwa 2-30 Azuchicho, Higashi-ku, Osaka City International Building Minolta Camera Co., Ltd. (72) Inventor Takeo Takarada 2-30-30 Azuchicho, Higashi-ku, Osaka Osaka Tokiwa Minolta Camera Co., Ltd. (72) Inventor Nobuyuki Taniguchi 2-30 Azuchicho, Higashi-ku, Osaka City Osaka City International Building Minolta Camera Co., Ltd. Document JP-A-58-105139 (JP, A) JP-A-58-218089 (JP, A) JP-A-55-89823 (JP, A) JP-A-58-166331 (JP, A) 152226 (JP, A) JP-A-57-212422 (JP, A)

Claims (2)

(57) [Claims] A camera system comprising a camera body and a camera accessory detachable from the camera body, a circuit element in the camera body which is provided in the camera body and performs a predetermined operation, and an operation of the accessory which is provided in the camera accessory. Control means for controlling the operation of the circuit element in the camera body and the control means in the accessory provided in the camera body, and between the control means and the circuit element in the camera body and the control means in the accessory. A common data bus that performs serial data communication with the control unit, and an independent unit that connects the control unit with the circuit element in the camera body and the control unit in the accessory in order to select an object to perform data communication with the control unit. A body that has a chip select line and supports selections made through the chip select line The control means in the circuit element or the accessory and the control means in the camera body are configured to perform data communication via the data bus, and the control means in the accessory is selected via a chip select line. A camera system characterized in that it is configured to control an accessory independently of the control means in the main body based on the transmitted data. 2. The camera system according to claim 1, wherein said camera accessory is a flash device detachable from a camera body.