JPH0743773A - Camera - Google Patents

Abstract

PURPOSE:To operate a camera without causing malfunction and to smoothly and surely photograph by selectively switching two power-supply voltage in accordance with a mounted photographic lens. CONSTITUTION:In the case of a lens mounted on the camera body 1' is a 2nd interchangeable lens, a control circuit for a 2nd interchangeable lens 4 is controlled by a lens driving signal from the terminal SCLK/P31(SI/P32) of a microprocessor(MCU) 10', and a motor rotating direction is controlled by the control circuit so as to drive a range ring, then, focusing is conducted. Meanwhile, when the mounted lens is a 1st interchangeable lens, the range ring of the 1st interchangeable lens is not driven by the lens driving signal interchangeable lens is not driven by the lens driving signal from the terminal SCLK/P31(SI/ P32) of the MCU 10', so that the signal of a focus detecting part 12 is not changed. At this time, an output signal is generated from the terminal PO by the MCU 10', and a voltage to be impressed on a contact 1'a is switched by a switching circuit 16 from a voltage V2 to a voltage V1 based on the output signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a first taking lens having a circuit operating at a first power supply voltage, and a second taking lens having a circuit operating at a second power supply voltage different from the first power supply voltage.
The present invention relates to a camera that can be selectively attached with the taking lens of.

[0002]

2. Description of the Related Art Conventionally, for example, JP-A-54-10862.
There are interchangeable lenses disclosed in Japanese Patent Laid-Open No. 8 and Japanese Patent Laid-Open No. 60-52812, which are mounted on a camera for use as needed. That is, these interchangeable lenses have an electrical contact for exchanging data with the camera body side, and a control circuit for receiving a power supply from the camera body side through the electrical contact and performing a predetermined operation. It is made up of In the camera system including the interchangeable lens and the camera body, various information on the camera body side is electrically read by the camera body side, and the control unit on the camera body side controls exposure based on the read information.
Focus detection control and the like are performed, and the range ring of the interchangeable lens is driven to the in-focus position according to the focus detection control.

[0003]

However, in the conventional example and other conventional techniques disclosed in the above publication,
Only a camera system consisting of a particular interchangeable lens and a camera body dedicated to the interchangeable lens is mentioned.

Therefore, consider a camera of the type having interchangeable lenses of the first and second types, having two of the first and second power supply voltages, and selectively switching the two power supply voltages. When the interchangeable lens of the first or second type is selectively attached to the camera body,
Conventionally, there has been no technology that considers the operation of the control circuit on the interchangeable lens side without malfunction.

The present invention has been made in view of the above technical background, and has two first and second power supply voltages, and the two power supply voltages are selectively switched. It is an object of the present invention to provide a camera that can operate without causing a malfunction when two types of photographing lenses that operate at respective power supply voltages are mounted on different types of cameras and used properly.

[0006]

The gist of the present invention for achieving the above object is to provide a first photographing lens (2) having a circuit that operates at a first power supply voltage, and the first power supply voltage. In a camera capable of selectively mounting a second taking lens (4) having a circuit that operates with a different second power supply voltage, the camera can be connected to the first taking lens and the second taking lens (4). Terminals (1′a to 1′e), a first power supply (V1) that supplies the first power supply voltage, a second power supply (V2) that supplies the second power supply voltage, and The selection means for selecting one of the first power supply voltage and the second power supply voltage and outputting it to the terminals (1′a to 1′e), and the first taking lens (2) are attached. Is selected, the first power supply voltage is selected, and when the second taking lens (4) is attached, And a control unit that controls the selection unit to select the second power supply voltage.

[0007]

In the camera according to the present invention, the first taking lens (2) and the second taking lens (4) are selectively used as required. The first taking lens (2) operates at a first power supply voltage, and the second taking lens (4) operates at a second power supply voltage different from the first power supply voltage.

When the first photographing lens or the second photographing lens (4) is attached to the camera, the terminals (1'a-1 ')
The photographing lens and the camera are connected by e). The control means detects which photographic lens is attached, selects the first power supply voltage when the first photographic lens (2) is attached, and causes the second photographic lens (4) to operate. When mounted, it is supported by the selection means to select the second power supply voltage. The selection means receiving this support selects the first or second power supply voltage suitable for the attached shooting lens and outputs it to the terminals (1′a to 1′e), and the shooting lens is driven by the correct power supply voltage. Works properly.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Various embodiments of the present invention will be described below with reference to the drawings. In the description of each embodiment, the same parts are designated by the same reference numerals, and the duplicated description will be omitted. First
1 to 10 show a first embodiment of the present invention. The camera according to the present invention corresponds to a camera body of a third type, which will be described later, and can be mounted with either the first or second photographing lens. In order to clarify the technical background, the first type camera body dedicated to the first taking lens and the second type camera body dedicated to the first taking lens are described in the first half.

FIG. 1 shows a camera of a first type having a first power supply V1 (in the following description, the voltage thereof, that is, the first power supply voltage is also represented by V1. Here, V1 = 5V). A body (hereinafter, simply referred to as a first camera body) 1 and a first type interchangeable photographing lens (hereinafter, simply referred to as a first camera body 1) according to the first embodiment. 3 is a block diagram showing a camera system including an interchangeable photographing lens) 2.

As shown in FIG. 1, the circuit of the first camera body 1 and the first interchangeable photographing lens 2 are arranged when the first interchangeable photographing lens 2 is attached to the first camera body 1. ,
The respective electrical contacts (hereinafter, simply referred to as contacts) 1a-2a, 1b-2b, ..., 1e-2e are connected to each other.

In the circuit of the first camera body 1, contacts 1a to 1e arranged on the mount portion, a microcomputer (hereinafter referred to as MCU) 10, and a known exposure control portion 1 are provided.
1, a known focus detection unit 12, a motor drive unit 13, a motor 14, a coupling 15 that rotates in conjunction with the motor 14, and a power switch SW1 for supplying the first power supply voltage V1 to the terminal 1a are provided. There is.

The MCU 10 is provided with an input / output terminal P1, a serial clock terminal SCLK, a serial input terminal SI and a serial output terminal SO for exchanging serial signals with the circuit of the first interchangeable photographing lens 2. .
Further, the MCU 10 includes an exposure control unit 11 and a focus detection unit 1.
2 and input / output terminals 11a, 12a and 13a for controlling the motor drive unit 13.

The exposure control section 11 performs a known exposure control, and the focus detection section 12 outputs a signal for determining the moving direction of the lens in order to perform a known focus adjustment control. .

The motor drive unit 13 drives the motor 14 by a signal calculated by the MCU 10 based on the output signal from the focus detection unit 12.

The coupling 15 is provided on the side of the first interchangeable photographing lens 2 when the first interchangeable photographing lens 2 is attached to the first camera body 1.
It is made to mesh with. Therefore, the motor 1
The rotation of 4 is transmitted to the distance ring 22 of the interchangeable photographing lens via the coupling 15 and the coupler 21 so that the focus is automatically adjusted.

The MCU 10 has a well-known serial interface function having an 8-bit input / output register. The serial input terminal SI and the serial output terminal S0 are connected to the contact point 1d, and the contact point 1d is connected to the contact point 2d of the first interchangeable photographing lens 2 to form a bidirectional data line.

The contact point 1c forms a serial clock line by being connected to the serial clock terminal SCLK of the MCU 10, and corresponds to the first interchangeable photographing lens 2
Is connected to the serial clock terminal SCLK of the MCU 20 on the side of the second interchangeable photographing lens 2 via the contact point 2c. Here, the serial clock is the first camera body 1
It is designed so that it is always output from the MCU 10 side. The contact 1b is connected to the input / output terminal P1 of the MCU 10 and forms a signal line for performing a handshake with the first interchangeable photographing lens 2.

The contact point 1e is for grounding, and when it is connected to the contact point 2e of the second interchangeable photographing lens 2, the GNDs thereof are common.

The contact 1a is for supplying the first power supply V1 to the second interchangeable photographing lens 2, and when the power switch SW1 on the first camera body 1 side is turned on, the first power supply V1 is turned on. In addition to being supplied to the circuit of the first camera body 1, the same power supply v1 is also supplied to the circuit of the first interchangeable photographing lens 2 via the contact 2a.

Next, the circuit section on the side of the first interchangeable photographing lens 2 will be described.

As shown in FIG. 1, in the circuit of the first interchangeable-photographing lens 2, electrical contacts (hereinafter, simply referred to as contacts) 2a to 2e arranged on a mount portion, microcomputers (hereinafter, MCU). 20), a coupler 21 meshing with the coupling 15, a distance ring 22, and a voltage detection means 23 for resetting and releasing the reset of the MCU 20.

The MCU 20 is a microcomputer having the same 8-bit serial interface function as the MCU 10. Further, in the MCU 20, like the MCU 10, the serial input terminal SI and the serial output terminal SO thereof are connected to the contact 2d. The reset terminal RESET bar of the MCU 20 (the reference numeral with a horizontal line above RESET in the figure) is connected to the output Q of the voltage detecting means 23.

The voltage detecting means 23 includes a comparator 24,
The reference voltage source Vo (in the following description, its voltage, that is, the reference voltage is also represented by Vo) is composed of resistors R1 and R2. The potential at the point where the first power supply voltage V1 is divided by the resistors R1 and R2

[0025]

[Equation 1]

Is input to the non-inverting input terminal of the comparator 24, and the reference voltage Vo is input to the inverting input terminal of the comparator 24. The power supply voltage Vcc applied through the contact 2a of the second interchangeable photographing lens 2 is

[0027]

[Equation 2]

At this time, the output Q of the voltage detecting means 23 becomes L, and the reset terminal RESET bar of the MCU 20 is set to L to bring the MCU 20 into the reset state.
It is designed to prevent the start of 0 operation.

On the other hand,

[0030]

[Equation 3]

At this time, the output Q of the voltage detecting means 23 becomes H, the reset terminal RESET bar of the MCU 20 becomes H, the reset state of the MCU 20 is released, and the MCU 20 starts a predetermined operation.

Here,

[0033]

[Equation 4]

It is assumed that

FIG. 2 shows that the first interchangeable photographing lens 2 is attached to the first camera body 1 so that the first power supply voltage V1 is applied to the circuit of the first interchangeable photographing lens 2. 6 is a timing chart of the output Q given from the voltage detection means 23 to the reset terminal RESET bar of the MCU 20 at this time.

As shown in FIG. 2, the applied power supply voltage Vcc is the first power supply voltage V on the first camera body 1 side with some delay due to the circuit impedance when the power is turned on.
Reach 1 Output Q is L when Vcc becomes Vo '
From H to H, the reset of the MCU 20 is released, and the MCU 20 can start a predetermined operation. At this time, the rise of the power supply voltage Vcc is steep,
If the reset time of MCU 20 becomes short,
The voltage detection means 23 may be provided with a delay means in advance.

FIG. 3 is a flow chart showing the operation of the MCU 20.

The operation of the MCU 20 will be described below with reference to FIG.

As shown in FIG. 3, in step # 1, the input / output terminal P2 is set to the input state in order to monitor the activation of the first camera body 1 from the MCU10 side.
Check if the input is L. If the input is L, the process proceeds to the next step # 2. If the input is H, it is assumed that there is no activation from the MCU 10 side, and step # 1
Returning to the above, the processing is repeated until the input at the input / output terminal P2 becomes L.

At step # 2, the serial output terminal SO
Is set to a high impedance to enable the input of the serial clock from the MCU 10, the input / output terminal P2 is set to the output mode, and the input / output terminal P2 outputs L.
The MCU 10 side of the first interchangeable photographing lens 2 is notified to the MCU 20 side that the response preparation is completed.

In the next step # 3, the process is repeated until 8 pulses of the serial clock are received from the MCU 10, and the serial flag is set by receiving 8 pulses. At this time, the process proceeds to the next step # 4.

At step # 4, H is output from the input / output terminal P2 to indicate that the instruction from the MCU 10 has been received. Next, in step # 5, the 8-bit contents of the serial input / output register are stored in the X register.

In step # 6, the data in the memory indicated by the X register is transferred to the serial input / output register.

At the next step # 7, the MCU sets the output of the input / output terminal P2 at L and the preparation for data transfer is completed.
Notify the 10 side.

At the next step # 8, similar to step # 3, the process is repeated until the serial flag is set. In the future, in synchronization with the input of 8 pulses to the serial clock terminal SCLK, the data of the serial input / output register is bit by bit from the serial output terminal SO via the contacts 2d and 1d to the MC.
It is sent to the U10 side. Finally, in step # 9, the input / output terminal P2 is set to H, the process returns to step # 1, and MC
Wait for the next activation from the U10 side.

The above is the MCU on the side of the first interchangeable photographing lens 1.
It is a function of 20.

In step # 6, the data in the memory indicated by the contents of the X register is transferred to the serial input / output register. For example, the data shown in Table 1 can be stored in this memory.

[0048]

[Table 1]

Table 1 shows the data of the 50 mm F1.4 lens, and the data 50 showing the focal length is contained at the address 00. Address 01 is a spare memory area containing 00. Address 0 contains data 0C indicating the maximum aperture value. F1.4
Since the open aperture value of the lens is AV = 1, if this open aperture value (AV = 1) is expressed in 1/12 EV steps, there are 12 steps, and if this 12 is expressed in hexadecimal, it becomes 0C. If the minimum aperture is F16 (AV8), the maximum number of aperture stages is 7, so these 7 stages are 1 / similar to address 02.
If it is expressed in 12 EV steps, there are 84 steps, and if this 84 is expressed in hexadecimal, it becomes 54. This is the data at address 03.

Lens type data is entered at address 04. Since this is a standard lens, the most significant bit of 8-bit data is set to 1 and 80 data is stored. 0
The correction amounts (1) to (3) for AF are stored at addresses 5 to 07. It is possible to add more data to the address 08 onward, but the description is omitted here.

As described above, the MC on the first interchangeable photographing lens side
Since the U20 is configured, when the MCU 20 receives address data indicating the required data type from the MCU 10 of the first camera body 1, the MCU 20 can send the corresponding data to the MCU 10.

FIG. 4 is a flowchart showing a subroutine of serial input / output processing of the MCU 10 on the side of the first camera body 1. Hereinafter, based on FIG. 4, the MCU
The input / output processing subroutine 10 will be described.

The MCU 10 carries out arithmetic processing for exposure control and focus adjustment control. In the process, when data peculiar to the lens is required, it enters the subroutine of serial input / output processing shown in FIG. The data can be taken out from the MCU 20 side.

As shown in FIG. 4, first, in the first step # 101, the input / output terminal P1 is set in the output mode, and L is output from the input / output terminal P1.
MCU 2 on the side of the first interchangeable photographing lens 2 via b and 2b
The input / output terminal P2 of 0 is activated.

At the subsequent step # 102, the address data for designating the memory address on the MCU 20 side, which is determined by the required data, is transferred to the serial input / output register of the MCU 10. For example, if the open aperture value is required, the address data 02 indicating the address where the data is stored may be transferred to the serial input / output register.

In step # 103, after measuring for a predetermined time, the input / output terminal P1 is set to H level and the input mode is set.
Go to step # 104.

At step # 104, it is checked whether the input at the input / output terminal P1 is L or not. When the response preparation is completed on the MCU 20 side, the input of the input / output terminal P1 becomes L, and otherwise, it becomes H. When the MCU 20 side becomes responsive and the output of the input / output terminal P2 becomes L, it is detected and the process proceeds to step # 105.

In step # 105, by starting the serial clock from the serial clock terminal SCLK of the MCU 10, the address data stored in the serial input / output register is output from the serial output terminal SO in synchronization therewith.

By monitoring the serial flag in step # 106, the process is repeated until the 8-bit serial transfer is completed. When the flag is set and the serial transfer is completed, the process proceeds to step # 107.

In step # 107, the measurement is performed for a predetermined time so that the input / output terminal P2 on the MCU 20 side is changed from L to H.

At step # 108, it is checked whether the terminal P1 is L or not. If preparation for data transfer is completed on the MCU 20 side, L is input to the input / output terminal P1, so the process proceeds to the next step. If not, the process is repeated.

In step # 109, the serial output terminal SO of the MCU 10 is set to high impedance, and then a clock pulse is generated from the serial clock terminal SCLK. The data of the interchangeable photographing lens 2 is input.

In step # 110, the serial flag is monitored in the same manner as in step # 106, and when the 8-bit serial transfer is completed, the process can proceed to the next step.

In step # 111, the data of the serial input / output register is stored in a predetermined memory to complete the processing of the subroutine and return to the main flow.

By the above operation, for example, the MCU 10
If a large aperture value is required on the side, send the O2 Madres data from the MCU10 to the MCU20, and if the attached lens is a 50mm F1.4 lens, the OC data will be MCU.
It will be returned from 20. With this data, MCU10
It suffices to perform exposure control, display calculation or focus adjustment control.

FIG. 5 is a timing chart showing an example of transmission / reception of a serial signal between the first camera body 1 and the first interchangeable photographing lens 2.

In FIG. 5, 1 is an output waveform from the input / output terminal P1 of the MCU 10, and 2 is a waveform from the input / output terminal of the MCU 20. Since the input / output terminals P1 and P2 are composed of open drains and pull-up resistors, whichever of the input / output terminals P1 and P2 is connected when the input / output terminals P1 and P2 are connected via the contacts 1b and 2b. When one of the outputs is L, the combined output is L and 3
It becomes a waveform like. Reference numeral 4 denotes a waveform of the serial clock output from the serial clock terminal SCLK of the MCU 10. When the contacts 1c and 2c are connected, the serial clock of the waveform 4 is input to the MCU 20.

Reference numeral 5 is an output waveform (address data waveform) of the serial output terminal SO of the MCU 10, and reference numeral 6 is an MCU.
20 is an output waveform of 20 serial output terminals SO (a waveform of data of the open F value of the lens in the figure). When the serial output terminals SO, SO are connected via the contacts 1d, 2d, the combined output when one of the serial output terminals SO, SO is L is Similarly, it becomes L and has a waveform like 7.

Next, the timing chart of FIG. 5 will be described in time series.

In step # 101, the MCU 10 shifts the output of the input / output terminal P1 from H to L (t = t1), and the MCU 20 detects it at the input / output terminal P2 and advances from step # 1 to # 2. , The output of the input / output terminal P2 is changed from H to L (t = t2). In step # 103, the MCU 10 changes the output of the input / output terminal P1 from L to H after measuring the predetermined time (t = t3).

At this time, since the waveform of the above 3 is L and L is input to the input / output terminal P1, the MCU1
For 0, the process proceeds from step # 104 to # 105 to start the serial clock (t = t4). Then, in synchronization with this serial clock, the address data of the waveform 5 is output bit by bit from the serial output terminal SO of the MCU 10. For example, when reading the data of the open F value with the first camera body 1, since this data is located at address 02, the lower bit (LSB) is synchronized with the serial clock from the serial output terminal SO of the MCU 10. )
From 01000000 is output one bit at a time.

At this time, since the serial output terminal SO of the MCU 20 is in the high impedance state in step # 2, the waveform of 7 becomes 01000000 like the waveform of 5 and enters the serial input terminal SI of the MCU 20.

8-pulse serial clock is MCUP2
When input to the serial clock terminal SCLK of 0 (t
= T5), the transfer of this data to the serial input register of the MCU 20 is completed, the MCU 20 proceeds from step # 3 to # 4, and when the output of the input / output terminal P2 is changed from L to H, the waveform of 3 is also L. To H (t = t6).
Then, the MCU 20 proceeds to steps # 5 and 6 and the MCU
The MCU according to the data of 20 serial input registers
The address of the memory in 20 is designated, and the designated data is output to the serial input register. MCU20
At step # 7, when the data transfer preparation is completed, the output of the input / output terminal P2 is changed from H to L (t = t7).

As a result, the input / output terminal P of the MCU 10
When 1 becomes L, the MCU 10 performs steps # 108 to #
The process proceeds to 109 to restart the serial clock (t = t8). In synchronization with this serial clock, the data of the open F value is output from the serial output terminal of the MCU 20 bit by bit.

As shown by the lens in Table 1, when address 02 is specified, the specified data is 0C, so MCU2
The output 6 from the serial output terminal SO of 0 is 00110000 from the lower bit. At this time, since the serial output terminal SO of the MCU 10 has a high impedance in step # 109, the output waveform of 7 changes like the waveform of 6 and is input from the serial input terminal SI of the MCU 10.

The 8-pulse serial clock is used by the MCU 20.
When input to the serial clock terminal SCLK of (t =
t9), the data is transferred to the serial input register of the MCU 10, that is, the open F value data is 00110000 (0
The transfer of C) is completed.

The subroutine processing of the MCU 10 is completed by storing the open F value data read in step # 111 in the storage section. On the other hand, the MCU 20 changes the input / output terminal P2 from L to H in step # 9 (t = t10
), And returns to step # 1 to wait for the next instruction.

Next, referring to FIG. 6, the first shown in FIG.
Another camera system different from the camera system according to the embodiment will be described.

The camera system shown in FIG. 6 has a second power source V2 (in the following description, its voltage,
The power supply voltage of is also represented by V2. Here, V2 = 3V. ) Of a second type camera body (hereinafter, simply referred to as a second camera body) 3 and an interchangeable lens of a second type (hereinafter, simply referred to as a second camera body 2) dedicated to the second camera body 2. 2 is called an interchangeable lens) 4).

The second camera body 3 has an exposure control unit 11,
It is composed of the focus detection unit 12 and the MCU 30, and the second power source V2 is turned into the second power source by closing the power switch SW2.
Is supplied to the entire circuit of the camera body 3, and the voltage V from the contact 3a of the second camera body 3 to the side of the second interchangeable lens 4 via the contact 4a of the second interchangeable lens 4.
2 power is supplied. The contact 3e is for grounding, and by connecting to the contact 4e for grounding of the second interchangeable lens 4, both GNDs are common. Contact 3c is MCU3
0 is connected to the terminal P31, and the focus detection unit 12 outputs the MCU 30 to the distance ring 2 of the second interchangeable lens 4.
When 2 should be moved from the closest distance to the infinity (∞) direction, when it is determined that it should, the output of the terminal P31 changes from H to L. On the other hand, when the MCU 30 determines that it should move from infinity (∞) to the closest direction, the output of the terminal P32 connected to the contact 3d changes from H to L.

The second interchangeable lens 4 includes a control circuit 40.
, The motor 47, and four transistors T for controlling the rotation direction of the motor 47 by the output of the control circuit 40.
r1 to Tr4 and a distance ring 22 connected to the motor 47 are provided. Control circuit terminals P41, 42, 43,
44, 45 and 46 are respectively connected to the contact 4c, the contact 4d, the base of the transistor Tr1, the base of the transistor Tr2, the base of the transistor Tr3 and the base of the transistor Tr4.

The second interchangeable lens 4 is attached to the second camera body 3, and the contacts 3a and 4a, 3c and 4c, 3d and 4 are attached.
When d, and 3e and 4e are respectively connected, the second
The drive signal from the camera body 3 drives the motor 47 via the control circuit 40 to move the distance ring 22 to adjust the distance.

Control circuit 40 operates as shown in Table 2.

[0084]

[Table 2]

The operation of the control circuit 40 will be described below.

The contacts 4c and 4d are "H" and "H", respectively.
When the inputs to the terminals P41 and P42 are "H" and "H", the outputs from the terminals P43 to P46 are "H" and
Transistors Tr1 to Tr4 become "H", "L", "L"
Are all off. As a result, no current flows through the motor 47, and the motor 47 is stopped.
At this time, the distance ring 22 is also stopped.

Next, the contacts 4c and 4d are respectively set to "L",
It becomes "H" and the terminals P41 and P42 are "L" and "H".
In the case of, the outputs of the terminals P43 to P46 become "L", "H", "L", "H", respectively, the transistors Tr1 and Tr4 are turned on, and the transistors Tr2 and Tr3 are turned off.
It becomes FF. As a result, a forward current flows through the motor 47, the motor 47 rotates in the forward direction, and the distance ring 22 is driven from the closest side to the infinity (∞) direction.

On the other hand, the contacts 4c and 4d are "H",
Becomes "L", and terminals P41 and P42 are "H",
When it is "L", the output of the terminals P43 to P46 is "H",
When it becomes "L", "H", "L", contrary to the above case, the transistors Tr2 and Tr3 are turned on and the transistors Tr1 and Tr4 are turned off. This makes the motor 4
A negative current flows through 7, the motor 47 rotates in the negative direction, and the range ring 22 is driven from the infinity side to the close direction.

As described above, in the camera system of FIG. 6, when the second interchangeable lens 4 is attached to the second camera body 3, the control signal corresponding to the output of the focus detection unit 12 is set to the micro level. The computer 30 has terminals P31 and P32.
To the control circuit 40 of the second interchangeable lens 4, the motor 47 is controlled, and the distance ring 22 is driven by the motor 47, whereby the focus adjustment of the second interchangeable lens 4 is automatically performed. .

Next, a camera body of the third type having the first power source V1 and the second power source V2 and capable of driving both the first interchangeable lens 2 and the second interchangeable lens 4. 1 '(hereinafter referred to simply as the third camera body) will be described.

FIG. 7 is a block diagram of the third camera body 1 '. In FIG. 7, parts having the same functions as those of the first camera body 1 shown in FIG. 1 are designated by the same reference numerals. Further, an element newly added to the third camera body 1'compared to the first camera body 1 is a function of switching the second power source V2 for the second interchangeable lens 4 and the power source voltage supplied to the interchangeable lens. It is a switching circuit 16 having.

The switching circuit 16 is connected to the terminal P of the MCU 10 '.
The second power source V2 for the second interchangeable lens 4 or the first power source V1 for the first interchangeable lens 2 when the power switch SW1 is turned on is selected by the signal from O and is selected. The power supply voltage V1 or V2 is output to the contact 1'a. When the first power supply V1 is not applied to the switching circuit 16, the second power supply V2 is connected to the switching circuit 1
It is designed so that it is not supplied from the output terminal of 6.

The MCU 10 'is similar to the MCU 10, but has software for driving the first interchangeable lens 2 and software for driving the second interchangeable lens 4 built therein.

The MCU 10 'has a terminal PO for controlling the switching circuit 16. The terminals P1, SCLK / P31, SI / P32 and SO of the MCU 10 'are
When the first interchangeable lens 2 is attached, the MCU 10
Of the terminals P1, SCLK, SI and SO of the above, while the second interchangeable lens 4 is attached,
It functions similarly to the terminals P31 and P32 of the MCU 30.
The terminals P1, SCLK / P31, SI / P32 and SO have pull-up resistors R11 to R2 connected to the power supply voltage V1 or V2 supplied from the switching circuit 16 to the interchangeable lens side.
Since it is pulled up by R13, the lens drive signal supplied to each interchangeable lens 2 or 4 is configured not to exceed the power supply voltage V1 or V2 applied to the contact 1'a.

The contacts 1'a to 1'e are provided on the mount portion of the lens at the same positions as the contacts 1a to 1e. Therefore, when the first interchangeable lens 2 is mounted, the contacts 1'a to 1'e are the contact points 2 of the first interchangeable lens 2.
On the other hand, when the second interchangeable lens 4 is mounted, the contact point 1'a is connected to the contact point 4a, and the contact points 1'c to e are connected to the contact points 4c to 4e, respectively. There is.

Next, the operation of the third camera body 1'when the first interchangeable lens 2 or the second interchangeable lens 4 is attached will be described.

The MCU 10 'carries out processing on the assumption that the first interchangeable lens mounted is the second interchangeable lens 4. That is, the switching circuit 16 is connected to the terminal P of the MCU 10 '.
The second power supply V2 is selected as the power supply voltage by the output from O, and this second power supply V2 is applied to the contact 1'a. In this state, the MCU 10 'determines the driving direction of the lens based on the output from the focus detection unit 12, and the terminal SCL
Set K / P31 and SI / P32 in output mode. Then, the MCU 10 'sends a lens drive signal according to the determined lens drive direction to the terminal SCLK / P31.
Alternatively, it is output from SI / P 32 and the control of Table 2 is performed by the lens drive signal.

At this time, if the lens mounted on the third camera body 1'is the second interchangeable lens 4, the MCU 1
The control circuit 40 of the second interchangeable lens 4 is controlled according to Table 2 by the lens driving signal from the 0'terminal SCLK / P31 or SI / P32, and the control circuit 40 controls the rotation direction of the motor 47. Distance ring 22
To adjust the focus. At this time, as the range ring 22 is driven, the signal of the focus detection unit 12 changes, so that the MCU 10 ′ detects the change of the signal of the focus detection unit 12 so that the mounted lens is the second interchangeable lens 4 Is determined.

If the lens mounted on the third camera body 1'is the first interchangeable lens 2, the MCU is
Since the distance ring 22 of the first interchangeable lens 2 is not driven by the lens drive signal from the terminal SCLK / P31 or SI / P32 of 10 ', the signal of the focus detection unit 12 does not change. At this time, the MCU 10 'outputs an output signal from the terminal PO, and the switching circuit 16 switches the power supply voltage applied to the contact 1'a from V2 to V1 by the output signal, and the MCU 10' is shown in FIG. Enter the subroutine processing shown. Then, the MCU 10 'of the third camera body 1'and the MCU 20 of the first interchangeable lens 2
The information shown in the timing chart of FIG. 5 is transmitted and received between the camera and the camera, whereby the exposure control or the automatic focus adjustment control is performed.

Next, considering the situation in which the camera system shown in FIG. 1 and the camera system shown in FIG. 6 coexist and the third camera body 1'shown in FIG. 7 exists, The operation of the voltage detecting means 23 will be described in comparison with the operation of the known microcomputer reset circuit 23 'shown in FIG.

First, the voltage detecting means 23 of the first interchangeable lens 2 shown in FIG. 1 is connected to the known reset circuit 2 shown in FIG.
The interchangeable lens replaced with 3'is the first camera body 1
Consider the case of attaching to.

In this case, when the power supply switch SW1 of the first camera body 1 is turned on and the first power supply voltage V1 is supplied to the power supply line (which voltage is represented by Vcc), FIG. As shown, this Vcc does not reach the first power supply voltage V1 immediately due to the internal resistance of the circuit. At this time, the waveform of the output Q'of the reset circuit 23 'reaches the threshold voltage Vth with a delay of a time constant determined by the resistor R and the capacitor C, as shown in FIG. When the output Q'has reached the threshold voltage Vth, the MCU 20 is released from reset. This threshold voltage Vth is slightly different depending on the characteristics of the MCU 20, but is generally a value near 1/2 Vcc.

Therefore, the level of the threshold voltage Vth changes depending on the power supply voltage.
In the case of FIG. 9 in which a single power source is supplied, no problem occurs, but interchangeable lenses having different power supply voltages are used for the same camera body (for example, the third camera body shown in FIG. 7). When the control is performed by 1 '), there are the following problems.

FIG. 10 shows the power supply voltage Vcc when the interchangeable lens is attached to the third camera body 1'shown in FIG. 7, and the first voltage using the voltage detection means 23 as shown in FIG. A waveform of the output Q of the voltage detecting means 23 when the interchangeable lens 2 is attached to the third camera body 1 ',
6 is a timing chart showing a waveform of an output Q'of the reset circuit 23 'when the first interchangeable lens 2 in which the voltage detecting means 23 is replaced by a reset circuit 23' is attached to the third camera body 1 '. .

As shown in FIG. 10, the power supply voltage V when the interchangeable lens is attached to the third camera body 1 '.
The voltage cc starts to be applied at time t = t0, and reaches a second power supply voltage V2 suitable for the second interchangeable lens 4 at time t = t1 due to internal resistance. At this time, the third camera body 1'identifies the type of the interchangeable lens mounted by the method described above. When the third camera body 1'identifies that the mounted interchangeable lens is the second interchangeable lens 4, the power source voltage V2 is kept as it is and the predetermined processing is started.

On the other hand, when the third camera body 1'identifies that the attached interchangeable lens is not the second interchangeable lens 4, the third camera body 1'is replaced by the first interchangeable lens 2. Start supplying suitable first power supply voltage V1 (t = t
3). The power supply voltage Vcc is t = t5 due to the internal resistance.
At the point of time, the first power supply voltage V1 is reached.

When the first interchangeable lens 2 using the conventional reset circuit 23 'is mounted on the third camera body 1'which operates as described above, as shown in FIG.
The output Q'of the conventional reset circuit 23 'is released when it becomes 1/2 of the second power supply voltage V2 (t = t2). Then, even if the third camera body 1'determines that the second interchangeable lens 4 is not the second interchangeable lens 4 and the first power supply voltage V1 is supplied, not only a new reset release signal is generated, but also from V2 to V1. There is a problem that the MCU 20 receives noise due to a large change in the power supply voltage and the function itself cannot be guaranteed.

However, when the first interchangeable lens 2 having the voltage detecting means 23 according to the first embodiment of the present invention is attached to the third camera body 1 ', it is shown in FIG. When the power supply voltage Vcc reaches the reference voltage Vo '
At (t = t4), the output Q of the voltage detecting means 23 changes from L to H, and the reset of the MCU 20 is released. Therefore, MC
U20 can start its operation without malfunction.

In the case shown in FIG. 10, it is assumed that it takes time for the power supply voltage Vcc to rise, so that no delay circuit is provided. However, the power supply voltage V
When the rising edge of cc is steep, a delay circuit may be inserted between the voltage detection circuit 23 and the reset terminal RESET bar of the MCU 20 (horizontal line above RESET).

Next, a second embodiment of the present invention will be described with reference to FIG.

FIG. 11 is a block diagram showing a first interchangeable lens 2A according to the second example.

The first interchangeable lens 2A has the same function as that of the first interchangeable lens 2 according to the first example.

As shown in FIG. 11, the first interchangeable lens 2A is provided with a control circuit 20 ', a voltage detecting means 23 similar to that in the first embodiment, and a gate means 25. .

The control circuit 20 'may be composed of a microcomputer like the MCU 20, and may be any one having the function shown in FIG.

The gate means 25 is inserted between the input / output terminal of the control circuit 20 'and the contacts 2b, 2c, 2d, and the EN terminal is controlled by the output Q of the voltage detecting means 23. That is, when the output Q is H,
The input of the EN terminal becomes H, and the input / output terminal of the control circuit 20 'and the contacts 2b, 2c, 2d are connected. When the output Q is L, the input of the EN terminal becomes L and the connection between the two is cut off.

Therefore, when the power supply voltage Vcc on the side of the first interchangeable lens 2A does not reach the predetermined value (the reference voltage Vo '), the contacts 2b, 2c, 2d are disconnected from the control circuit 20', and are moved to the camera body side. The first interchangeable lens 2A is not affected by the camera body, and there is no room for malfunction.

FIG. 12 is a block diagram showing a first interchangeable lens 2B according to the third example of the present invention. The difference from the second embodiment of FIG. 11 is that a gate means 26 is inserted between the input / output terminal of the control circuit 20 'and the contact 2a instead of the gate means 25. The gate means 26 controls the control circuit 20 'when the input to the EN terminal is H.
Further, the power supply voltage Vcc supplied from the camera body through the contact 2a is applied to the control circuit 20 ', and when the input of the EN terminal is L, the power supply voltage is cut off.

According to the third embodiment, as in the case of the second embodiment shown in FIG. 11, when the power supply voltage Vcc supplied to the first interchangeable lens 2B does not reach the predetermined value, the camera body On the first interchangeable lens 2B side, and there is no room for malfunction of the first interchangeable lens 2B.

In each of the above-mentioned embodiments, the case where the present invention is applied to the interchangeable lens as the camera accessory has been described, but the present invention is also applicable to the intermediate ring, the teleconverter, the bellows, etc. which can be mounted on the lens mount of the camera body. Needless to say, can be applied.

Furthermore, in the first interchangeable lens 2, 2A or 2B according to each of the above-described examples, the first camera body 1
Alternatively, since the terminal 2b for starting the serial data transfer with the third camera body 1'is provided separately from the terminals 2c, 2d for transferring the data, the terminal 2b and the camera system shown in FIG. Even if the camera system shown in FIG. 2 is configured to be driven by the same power supply voltage, if the first interchangeable lens 2, 2A or 2B is mistakenly attached to the second interchangeable lens 3, There is no contact corresponding to the contact 2b of the first interchangeable lens 2, 2A or 2B on the side of the second interchangeable lens 3, and the first interchangeable lens 2, 2A or 2B does not operate.

Since the terminal 2b on the side of the first interchangeable lens 2, 2A or 2B is not connected to the terminals 3c, 3d on the side of the second camera body 3, the first interchangeable lens 2 , 2A or 2B is the second camera body 3
There is no possibility of receiving a false signal from the side. Therefore, even when the first interchangeable lens 2, 2A or 2B does not only transfer lens data as described in the above embodiment but also performs other operations, the first interchangeable lens 2
The interchangeable lens 2, 2A or 2B does not receive an erroneous signal from the second camera body 3 side.

[0122]

According to the camera of the present invention, the first photographing lens operating at the first power supply voltage and the second photographing lens having a different voltage are used.
When the second shooting lens that operates with the power supply voltage of is attached to a camera that can supply any power supply voltage and used properly,
Since the two power supply voltages are selectively switched according to the attached photographic lens, it is possible to always operate without malfunction, and it is possible to perform smooth and reliable photography.

[Brief description of drawings]

FIG. 1 is a block diagram showing a camera system including a camera body of a first type and an interchangeable lens of a first type according to a first example.

FIG. 2 is a timing chart showing the function of the voltage detecting means used in the first type interchangeable lens.

FIG. 3 is a flowchart showing an operation of a microcomputer used for the first type interchangeable lens.

FIG. 4 is a flowchart of a subroutine showing serial input / output processing of the microcomputer used for the camera body of the first type.

5 is a timing chart of serial input / output signals in the camera system shown in FIG.

FIG. 6 is a block diagram showing a camera system including a second type camera body and a second type interchangeable lens.

FIG. 7 is a block diagram showing a third type camera body that can be used for both the first type interchangeable lens and the second type interchangeable lens.

FIG. 8 is a circuit diagram showing a conventional reset circuit for a microcomputer.

FIG. 9 is a timing chart showing the relationship between the power supply voltage Vcc from the camera body side and the output Q ′ of the reset circuit.

10 is a diagram illustrating a power supply voltage Vcc from the camera body side and an output Q of a conventional reset circuit when the first type interchangeable lens is mounted on the third type camera body shown in FIG. 2 is a timing chart showing the relationship between the power supply voltage Vcc and the output Q of the reset circuit according to the embodiment.

FIG. 11 is a block diagram showing a first type interchangeable lens according to Example 2 of the present invention.

FIG. 12 is a block diagram showing a first type interchangeable lens according to Example 3 of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... 1st type camera body 1 '... 3rd type camera body 2; 2A; 2B ... 1st type interchangeable lens (camera accessory) 2a-2e ... Electrical contact 20 ... Microcomputer 20' ... Control circuit 23 ... Voltage detecting means

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G03B 17/14 7513-2K

Claims (1)

[Claims] 1. A first photographing lens having a circuit that operates with a first power supply voltage and a second photographing lens that has a circuit that operates with a second power supply voltage different from the first power supply voltage are selected. A camera that can be mounted on a terminal, a terminal connectable to the first taking lens and the second taking lens, a first power supply for supplying the first power supply voltage, and a second power supply voltage. A second power supply to be supplied, a selection unit that selects one of the first power supply voltage and the second power supply voltage and outputs the selected power supply voltage to the terminal, and when the first taking lens is mounted And a control unit that controls the selection unit to select the first power supply voltage and to select the second power supply voltage when the second taking lens is mounted. .