JPH0224105Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camera capable of storing photometric values, and particularly to a camera equipped with a device for canceling this storage.

2. Description of the Related Art Conventionally, as photometry methods for cameras, there have been known two types: a spot photometry method that measures light over a relatively narrow area of an object, and an average photometry method that measures light averagely over a relatively wide area. Here, the spot method is advantageous when adjusting the exposure level only to a specific, narrow area of the subject. However, if this spot method is used, there is a risk that the exposure level in areas other than narrow areas will be greatly deviated. On the other hand, with the average metering method,
After all, since it is an overall average, there is a risk that the exposure level of the main subject will be out of order.

For this reason, the applicant previously proposed in Japanese Patent Application No. 57-145393 that spot light metering was carried out on arbitrary parts of the subject, sequentially memorizing these light metering values, and controlling exposure based on these memorized values. We have proposed a camera that can do this.

On the other hand, there are cases where a number of photos are taken at the same exposure level, such as when taking a panoramic photo. In order to respond to such requests,
In the camera shown in Japanese Patent Application No. 57-145393 mentioned above, once a photograph is taken, the actual exposure value at the time of photographing is stored, and exposure control is performed for subsequent photographs based on this memorized exposure value. It also has a function (EE lock function) that allows you to do this.

However, when the above-mentioned storage of spot photometric values and actual exposure values is applied to a camera with interchangeable lenses, the following problems occur.

In other words, interchangeable lenses have various aperture values, and therefore the amount of light passing through the interchangeable lens itself changes during photometry. Therefore, there is no problem if you always use a lens with the same aperture, but if you change the lens to a lens with a different aperture after storing it, the exposure will be incorrect. In order to prevent this, it would be best to provide the interchangeable lens itself with a signal member that indicates its aperture value.
In this case, the configuration of the lens itself and the configuration of the camera, lens, and coupling portion become extremely complicated.

This invention was developed in view of the above problems, and the purpose of this invention is to provide a camera in which the stored value is always cleared each time the lens is replaced.

An embodiment of the camera according to the invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a plan view of a camera showing an embodiment of the present invention. This camera 10 is a so-called single-lens reflex camera, and has a photographic lens barrel 2 removably attached to the center of the front surface of the camera body 1, and a pentaprism housing 3 in the center of the top surface. It has a protruding triangular roof shape. As is well known, the photographic lens barrel 2 houses and holds a photographic lens 4 (see Fig. 2), and a front section on the outer periphery of the lens barrel 2 allows the aperture value to be set. A ring 5 and a shooting distance setting ring 6 are arranged so as to be rotatable in sequence. In addition, the camera body 1
In the left half of the upper surface partitioned by the pentaprism storage section 3, there are a film winding lever 8, a film frame number display window 9, a shutter release button 11, and an EE.
A lock operation knob 13, a spot input button 14, and an average light metering mode initial switch button 15 are provided. On the other hand, on the right half of the top of the camera body 1,
A film rewind knob 17, a film sensitivity setting dial 18, a film sensitivity display window 19, and an exposure correction operation knob 22 are provided.

In addition, in FIG. 1, the reference numeral 26 indicates the photographing lens barrel 2.
The operation button 27 is used to attach the camera to the camera body 1.
2 denotes a metal fitting for attaching a strap (not shown) to the camera body 1, and 28 denotes a viewfinder eyepiece window frame.

The EE lock operation knob 13 is rotatably arranged at the base of the pedestal of the shutter release button 11, and the EE lock operation knob 13 is rotatably arranged at the base of the pedestal of the shutter release button 11. The same knob 13 is located between the ``LOCX'' indicator and the ``CLEAR'' indicator.
It has been stopped in accordance with the indicators listed in . This EE lock operation knob 13 is used to select the EE lock shooting mode (hereinafter simply referred to as EE lock mode) in which multiple frames are photographed at the exposure level once taken, or to select the EE lock mode or spot metering shooting mode (hereinafter simply referred to as EE lock mode). Hereinafter, it is simply referred to as the spot metering mode.
SW ₃ (see Figure 4), and clear switch SW ₄
(See Figure 4). When the EE lock operation knob 13 is turned and the index of the knob 13 is set to the "EE.LOCK" index, the EE lock mode selection switch SW ₃ is closed, the VEE lock mode is selected, and the index is set to the "CLEAR" index. Then, the clear switch SW ₄ is closed, the EE lock mode and the spot metering mode are canceled, and the normal average metering photography mode (hereinafter simply referred to as average metering mode) is selected. When the rotation operation force is removed from the operating knob 13, the knob 13 automatically returns to its normal position by its own habit, but the EE lock mode and average photometry mode are maintained as they are.

The spot input button 14 is formed of a self-resetting type push button, and is adapted to be linked to a spot input switch _SW2 (see FIG. 4), which will be described later. This spot input button 14 allows the camera 1 to input the luminance value of the subject partially metered through the photographic lens 4.
This is an operating member for inputting and storing the electrical circuit 0, and also serves as an operating member for selecting a spot photometry mode. First press the spot input button 14 in the average metering mode.
When pressed, the spot input switch SW ₂ is closed and the spot metering mode is selected, and when the spot input button 14 is pressed for the second and subsequent times,
Spot brightness values are input and stored sequentially. Therefore, the spot input button 14 is
When you press the button continuously (n is any integer) times,
The first time the camera switches to spot metering mode, and the second and subsequent times the spot brightness value is input.
A total of (n-1) spot brightness value cameras 10
stored in memory. Note that the spot input button 14
The spot metering mode is not canceled by the self-return of the meter, and the mode can be canceled by pressing the average metering mode switching button 15 or by pressing the EE lock operation knob 13.
This is now done through operations that correspond to the ``CLEAR'' indicator.

The average photometry mode switching button 15 is a self-resetting push button, and is linked to an average photometry mode selection switch _SW1 (see FIG. 4), which will be described later. This average photometry mode switching button 15 is an operation member for switching the photographing mode from the spot photometry mode to the average photometry mode.

FIG. 2 shows the optical system of a single-lens reflex camera disposed within the camera 10 of this embodiment. As is well known, in the optical system of a single-lens reflex camera, a movable reflection mirror 31 that is tilted at an angle of 45 degrees with respect to the photographing optical path is rotatably disposed.
At this position for forming the viewfinder optical path, the object light that has entered the camera 10 through the photographic lens 4 is reflected at right angles upward and is made to enter the viewfinder optical system. The finder optical system includes a focusing glass 35 disposed at a position optically conjugate to the photosensitive surface of the photographic film 34.
A condenser lens 36 is placed directly above the focusing glass 35, and a pentaprism 37 is further placed directly above the condenser lens 36.
and a finder eyepiece lens 38 disposed to face the rear end surface which is the light output end surface of the pentaprism 37, and the rear end edge between the focusing glass 35 and the condenser lens 36. A photographing information display device 39 made of a light-transmissive liquid crystal display panel, which will be described later, is disposed on the side. Further, the center part of the movable reflection mirror 31 is processed with a half mirror or has fully transparent slits arranged in a row to form a semi-transparent part 31a.
Movable reflection mirror 3 corresponding to this semi-transparent part 31a
A total reflection mirror 32 is movably attached to the rear side of the mirror 1 so as to form a predetermined angle with the movable reflection mirror 31. This total reflection mirror 32 is
The subject light that has passed through the semi-transparent part 31a of the movable reflection mirror 31 is reflected toward the bottom of the camera 10, and this light is transmitted to the photometric light receiving device 4 disposed in the same part.
1 through the condensing lens group 30. As shown in FIG. 3, the photometric light receiving device 41 is formed in a rectangular shape and is tilted toward the front end of the bottom of the camera body 1 so as to look up at the total reflection mirror 32. . This photometric light receiving device 41 has a surface of an N-type semiconductor substrate 42.
P-type semiconductor region 43a with a square shape and a rectangular shape,
43b, cathode electrodes 44a and 44b are formed on the N-type semiconductor substrate 42, and the P-type semiconductor region 43
anode electrodes 45a and 45b are attached to the regions 43a and 43b, respectively, and the region 43a and the substrate 42 are connected to a photoelectric conversion element SPD ₁ ( Fourth
(see figure), and also forms a region 43b and a substrate 42.
is a photoelectric conversion element SPD ₂ that spot-meters the subject light reflected by the total reflection mirror 32 (see Figure 4).
is formed.

On the other hand, the connection mount portion of the camera body 1 to which the lens barrel 2 is connected is provided with the connection mount portion shown in FIGS.
As shown in the figure, an operating member 101 is provided for operating a second clear switch SW ₄₀ connected in parallel with the clear switch SW ₄ .

Here, FIGS. 17 to 19 show one example for selecting the clear switch SW ₄₀ . The mount portion 1a of the camera body 1 includes
A detection pin 101 as an operating member is provided, which is given the habit of protruding from the mount surface by a spring 100. Further, the second clear switch is located at the rear end of this detection pin 101.
SW ₄₀ is installed. This second clear switch SW ₄₀ is a normally closed switch, and when the lens barrel 2 is attached to the camera body 1, the detection pin 101 is closed by the mount 2a of the lens barrel 2.
It is designed to open when pressed.

Therefore, according to the above-mentioned system configuration, even if the operation knob 13 is not operated, it is necessary to
The EE lock mode and spot metering mode will be canceled and the stored values will be cleared.

Further, FIGS. 20 to 21 show other examples of operating the clear switch SW ₄₀ . An interlocking lever 5a that interlocks with the aperture ring 5 extends along the optical axis from the mounting surface of the lens barrel 2, as is known. On the other hand, an interlocking ring 1b is rotatably disposed on the back side of the mount surface 1a of the camera body 1. This interlocking cylinder 1b has a spring 1d
This gives it a counterclockwise rotational habit.
A pin 1d is fixedly provided on this ring 1b as the operating member 101. This pin 1d comes into contact with a suitable member and stops at the illustrated position where the switch SW ₄₀ is closed. Also, the interlocking ring 1
b is provided with a protrusion 1e that engages with the interlocking lever 5a when the lens barrel 2 is attached. The lens barrel 2 and the camera body 1 are connected by a known bayonet mount mechanism.

According to the above configuration, when attaching the lens barrel 2 to the camera body 1, first the two are joined at a position where the moving lever 5a engages with the protrusion 1e,
Then, by rotating the lens barrel clockwise, the two are combined. During this rotation, interlocking ring 1
b is also rotated clockwise to open switch SW ₄₀ .

Therefore, when the lens barrel 2 is removed from the camera body 1, the switch SW ₄₀ is always closed, and when the lens is attached, it is opened, resulting in the same effect as in the previous embodiment.

Although not shown, the operating member 101 may be linked to a button for attaching and detaching the interchangeable lens of the camera 10. That is, in order to remove the lens barrel 2, the interchangeable lens removal button must first be pressed. Therefore, in conjunction with the pressing operation of this button, the operating member 1
If _{the switch SW 40 is} closed via 01, the EE lock mode and the The spot metering mode will be canceled and the stored values will be cleared.

FIG. 4 shows an electric circuit in the camera 10 of this embodiment. In this electric circuit, reference numeral 60 indicates a reference voltage circuit, and its output terminal that generates the reference voltage Vref is connected to an operational amplifier.
It is connected to the non-inverting input terminals of A ₁ and A ₄ and the inverting input terminal of operational amplifier A ₅ . The output terminal is connected to a variable resistor RV ₄ for selecting a voltage according to the aperture value, and to the other terminal of a variable resistor RV ₅ for selecting a voltage according to the film sensitivity value and correction value. ing. The above operational amplifier
The inverting input terminal of A ₁ is grounded through semi-fixed resistor RV ₁ for brightness level adjustment, and the output terminal is connected to the emitter of transistor Q ₁ for generating logarithmic compression voltage.
and photocurrent logarithmic compression transistors Q ₂ and Q ₃
are connected to the respective emitters. The above transistor Q ₁ is formed of a PNP type transistor, and its base is connected to the non-inverting input terminal of operational amplifier A ₁ .
The collectors are respectively connected to the inverting input terminal of the same amplifier _A1 . The semi-fixed resistor RV ₁ has a current I ₁ = Vref / RV ₁ (a) that makes the potential at the inverting input terminal of the operational amplifier A ₁ equal to the reference voltage Vref through the emitter and collector of the transistor Q ₁ . As a result, a voltage V _A1 is generated at the output terminal of the operational amplifier A ₁ as follows: V _A1 = Vref + kT/qlnI ₁ /Is (b). However, k is the Boltzmann constant, T is the absolute temperature, q is the unit charge, and Is is the reverse saturation current (the same applies hereinafter).

Transistors Q ₂ and Q ₃ for logarithmic compression of the above photocurrent
are formed of PNP type transistors, the photoelectric conversion element SPD 1 for average photometry is connected in the forward direction between the base and collector of transistor Q ₂ , and the above photoelectric conversion element SPD ₁ is connected between the base and collector of transistor Q ₃ in the forward direction. Photoelectric conversion element for spot photometry
SPD ₂ is connected forward. The anode of photoelectric conversion element SPD ₁ is connected to the inverting input terminal of operational amplifier A ₂ , the cathode is connected to the non-inverting input terminal of operational amplifier A ₂ , and the anode of photoelectric conversion element SPD ₂ is connected to the inverting input terminal of operational amplifier A ₃ . , the cathodes are connected to the non-inverting input terminal of operational amplifier _A3 , respectively. The output terminal of operational amplifier A ₂ is connected to the inverting input terminal of amplifier A ₂ , and
It is also connected to the first input terminal of a multiplexer MPX ₁ consisting of a plurality of analog switches.
Further, the output terminal of the operational amplifier A ₃ is connected to the inverting input terminal of the amplifier A ₃ and the collector of a transistor Q ₆ , which will be described later, through a resistor R ₂ , and is also connected to the second input of the multiplexer MPX ₁ . Also connected at the end.

On the other hand, the non-inverting input terminal of the operational amplifier _A5 to which the reference voltage Vref is applied to the inverting input terminal is grounded through a semi-fixed resistor _RV2 for spot photometry brightness level adjustment. The output terminal of this operational amplifier _A5 is connected to the base of a PNP type transistor _Q4 , the collector of which is connected to the non-inverting input terminal of operational amplifier _A5 , and the emitter is connected to the non-inverting input terminal of operational amplifier _A5 .
Connected to the collector and base of PNP transistor _Q5 , respectively. Transistor _Q5 has the operating voltage Vcc applied to its emitter and its base
Connected to the base of PNP transistor _Q6 . The operating voltage Vcc is applied to the emitter of the transistor _Q6 , forming a current mirror circuit together with the transistor _Q5 , and its collector is connected to one end of the resistor _R2 . Above semi-fixed resistor
RV ₂ contains the inverting input terminal voltage Vref of operational amplifier A ₅ .
A current I ₂ = Vref / RV ₂ ...(C) such that the non-inverting input terminal voltage becomes equal flows through the emitter-collector of the transistor Q ₄ , and this current I ₂ flows through the transistors Q ₅ and
It also appears in _Q6 .

Now, assuming that the photocurrent I _P1 is flowing through the photoelectric conversion element SPD ₁ through the transistor Q ₂ , the voltage V _A2 at the output terminal of the operational amplifier A ₂ is V _A2 = V _A1 −kT/qlnI _P1 /Is ……( d), and by substituting the above equation (b), V _A2 = Vref + kT / qlnI ₁ / Is - kT / qlnI _P1 / Is = Vref + kT / qlnI ₁ / I _P1 ...(e) On the other hand, the photoelectric conversion element SPD ₂ Assuming that a photocurrent I _P2 is flowing through the transistor Q ₃ , the voltage V _A3 at the output terminal of the operational amplifier A ₃ is V _A3 = V _A1 −kT/qlnI _P2 /Is + (I _P2 + I ₂ ) R ₂ ... ...(f), and by substituting and rearranging the above equation (b), we get V _A3 = Vref + kT / qlnI ₁ / I _P2 + (I _P2 + I ₂ ) R ₂ ... (g).

Therefore, according to the photometric circuit in the camera of this embodiment, the output voltages V A2 and V _A2 of the operational amplifiers A ₂ and A ₃ are
Since V _A3 does not include the reverse saturation current Is, there is no influence of the reverse saturation current Is. Also, semi-fixed resistance
By adjusting RV ₁ , the current I ₁ changes and the output voltages V _A2 , V _A3 , that is, the outputs of average photometry and spot photometry can be adjusted. moreover,
By adjusting the semi-fixed resistor RV ₂ , the current I ₂ changes, and the output voltage V _A3 , that is, the output of spot photometry, can be adjusted independently.

On the other hand, the inverting input terminal of the operational amplifier _A4 , to which the reference voltage Vref is applied to the non-inverting input terminal, is grounded through the resistor _R1 . Also, this op amp A ₄
A variable resistor is connected between the inverting input terminal and output terminal of
An adjustment semi-fixed resistor RV ₃ is connected to generate a voltage according to the number of stages of RV ₄ and RV ₅ . The variable resistors RV ₄ and RV ₅ are connected to an operational amplifier in parallel.
It is connected between the output terminal of _A4 and the output terminal of the reference voltage circuit 60. The sliding contact terminal of the variable resistor RV ₄ is adapted to move in conjunction with an aperture (not shown), and is connected to the fifth input terminal of the multiplexer MPX ₁ , so that the aperture value AV The function is to generate a voltage corresponding to the voltage. In addition, the above variable resistor
The first sliding contact terminal of RV ₅ is adapted to move in conjunction with the film sensitivity setting dial 18 (see Figure 1), and is connected to the third input terminal of multiplexer MPX ₁ . film sensitivity value
It serves to generate a voltage corresponding to SV. The second sliding contact terminal of the variable resistor RV ₅ is adapted to move in conjunction with the exposure compensation operation knob 22 (see Figure 1), and is connected to the fourth input terminal of the multiplexer MPX ₁ . It is connected and serves to generate a voltage corresponding to the correction value CV.

As mentioned above, the multiplexer MPX ₁ is composed of multiple analog switches,
The first to fifth input terminals have an output voltage V _A2 of the operational amplifier A ₂ corresponding to the brightness value BV1 determined by average photometry,
The output voltage V _A3 of the operational amplifier A ₃ according to the brightness value BV 2 by spot photometry, the voltage at the first sliding contact terminal of the variable resistor RV ₅ according to the film sensitivity value SV,
A voltage is applied to the second sliding contact terminal of the variable resistor RV ₅ in accordance with the correction value CV, and a voltage is applied to the sliding contact terminal of the variable resistor RV ₄ in accordance with the aperture value AV. The multiplexer MPX ₁ is for selectively outputting one of the above five input information, and in order to select one information, its control signal input terminal is connected to a central processing unit consisting of a microcomputer. (Hereinafter, the CPU will be abbreviated.) 50 is connected to the output port O2. Further, the output terminal of the multiplexer MPX ₁ is connected to the inverting input terminal of a comparator A ₆ which together with the DA converter 58 constitutes a sequential comparison type AD conversion circuit. The input terminal of the D-A converter 58 is connected to the CPU 50.
The output terminal is connected to the non-inverting input terminal of the comparator _A6 .
Further, the output terminal of the comparator _A6 is connected to the input port I7 of the CPU50.

The output port 04 of the CPU 50 is an output port for driving the rear curtain locking magnet _Mg1 of the shutter, and is connected through a resistor _R3 to the base of a switching transistor _Q7 for magnet control. The transistor Q ₇ is formed of the NPN type, its emitter is grounded, and the collector is connected to the operating voltage Vcc through the coil of the magnet Mg ₁ .
is applied. Further, the output port 03 is an output port for driving a photographing information display device 39 made of a liquid crystal display panel, and is connected to an input end of the display device 39.

Input ports 11 to 16 of the CPU 50 all have built-in pull-down resistors (not shown), and each input port I1 to I6 has an average photometry mode selection switch SW ₁ and a spot input switch.
One end of SW ₂ , EE lock mode selection switch SW ₃ , clear switch SW ₄ , release switch SW ₅ , and trigger switch SW ₆ are connected to each other. Each of these switches SW ₁ to _{SW 6} is a normally open switch, and the operating voltage Vcc is applied to the other end of each switch. The average photometry mode selection switch SW ₁ is a switch for selecting the average photometry mode, and is closed in conjunction with the pressing operation of the average photometry mode switching button 15 (see Figure 1). There is. The spot input switch SW ₂ is a switch for selecting the spot photometry mode and inputting the spot brightness value, and is closed in conjunction with the pressing operation of the spot input button 14 (see Fig. 1). It's becoming like that. EE lock mode selection switch above
SW ₃ is a switch for selecting the EE lock mode, and is closed in conjunction with the operation of the EE lock operation knob 13 (see Figure 1) corresponding to the "EE.LOCK" indicator. There is. The clear switch SW ₄ is a switch for clearing the spot luminance value input in the spot metering mode and its calculation result value, and canceling the spot metering mode and the EE lock mode.
It is designed to close in conjunction with the operation of the EE lock operation knob 13 (see FIG. 1) corresponding to the "CLEAR" indicator. Also, this clear switch
A second clear switch SW ₄₀ is connected in parallel to SW ₄ . The above release switch SW ₅ is
This switch is used to release the shutter, and is closed when the shutter release button 11 (see Figure 1) is pressed, and opened when the exposure operation is completed. There is. The trigger switch SW ₆ is a switch for detecting the start of exposure, and is designed to close in conjunction with the upward movement of the movable reflection mirror 31 and open in conjunction with the downward movement of the movable reflection mirror 31.

FIG. 5 is a block diagram showing the internal configuration of the CPU 50, which is the core of the control system in the camera 10 of this embodiment. In the figure, a clock generator (CLOCK) 71 is a part that generates pulses that serve as a reference for the operation of the CPU 50, and a control circuit (CONT) 72 is a part that is a central part that controls the overall operation of the CPU 50. CPU50 is
It is necessary to transfer and process various binary data in an orderly manner according to a predetermined program order, but in order to do this, it is necessary to know when and for how long the gates inside the CPU 50 should be open, or which flip-flops should be opened. It is necessary to have a part inside the CPU 50 that determines whether to set or reset the CPU 50 depending on the state of the CPU 50 and the state of the input. doing this job
CONT72. The instruction register (INR) 73 is a part that temporarily holds the contents of a random access memory (RAM) 84, which will be described later, and the CONT 72 determines the state of each part of the CPU 50 based on the contents of this INR 73. The program counter (PC) 76 is a part that stores the address to be executed from now on in order to execute the program in an orderly manner.The program counter (PC) 76 is a part that stores the address to be executed from now on in order to execute the program in an orderly manner. . Stack pointer (SP) 77
When an interrupt instruction occurs or a jump instruction to a subroutine occurs, the PC7
6. Temporarily retain the contents of the accumulator (ACC) 79, index register (IX) 78, etc., which will be described later, without destroying them, when you want to return from those instructions and use them again. This is a register for IX78 is a register for storing an instruction execution address when executing an instruction in index address format. The arithmetic processing circuit (ALU) 81 is a part that performs operations related to arithmetic operations in the execution of instructions. It also performs logical operations such as logical sum or logical product of two memories. A condition code register (CCR) 82 is a register for storing a code used for detecting a state in a flag when executing an instruction requiring a judgment such as a branch instruction.
The determination function occupies an important position for the CPU 50, and in controlling the camera 10 of this embodiment, the state of each input port (“1” or “0”) is determined, as will be described later. There are often places where branch instructions are executed, either changing the flow of the program to be executed next or executing the instructions without changing the flow. This is CCR8
This is done by determining the state of the flag in step 2. CCR82 is a negative flag that becomes "1" when the result of execution of an instruction becomes negative in two's complement, "0" when the result becomes positive, and "0" when the result becomes "0". 1”,
A zero flag that becomes “0” when it is not “0”.
The overflow flag is set to "1" when the result causes a two's complement overflow, and "0" otherwise. "1" when a carry or borrow occurs from the unsigned binary number as a result of the operation. It is made up of various flags such as a carry flag that becomes "0" when no occurrence occurs. The memory buffer register (MBR) 75 is a register from which, when an address to be read is entered in the storage address register (SAR) 74 and a read instruction is issued to the memory, the contents of the specified address are read out.

The read-only memory (ROM) 83 is the CPU 5
This is for executing instructions while sequentially reading out the contents. Further, a random access memory (RAM) 84 is a memory that temporarily stores values during arithmetic processing and their results, or various input information. The display random access memory (DRAM) 85 is connected to the shooting information display device 39.
(See Figure 4) has an area that corresponds one-to-one to each segment of the liquid crystal display board forming the
When the content of a specific address in the DRAM 85 becomes "1", the corresponding segment of the liquid crystal display panel lights up in color. The liquid crystal drive circuit (LCDD) 61 is a circuit for driving the photographing information display device 39 formed of a liquid crystal display board to generate color.
A plurality of segment lines and common lines are each drawn out. As mentioned above, the input port (INPP) 88 includes seven input ports I1 to I7, and the output port (OUTPP) 8
9 is formed of four output ports O1 to O4, respectively (see FIG. 4), as described above. Note that all outputs of OUTPP89 are latch outputs.

Next, the flow of control of the CPU 50 configured as above will be briefly explained.

The CPU 50 repeats two cycles: first, a fetch cycle in which the instruction stored in the address in the memory specified by the PC 76 is loaded, and then an execute cycle in which the instruction is executed. First, the value of PC76 is SAR
74. At the same time, PC76 has
The contents that were previously stored in PC76 plus "1" are stored. When the address to be read is entered in the SAR 74, a read instruction is issued to the memory, and after a while, the contents of the address instructed to the MBR 75 are read out. The instruction code part is transferred to INR73. This is the fetish cycle. Following this, the execution cycle begins,
This operation differs depending on the contents of INR73. As an example, suppose that the INR 73 contains an instruction (LDA instruction) to load the contents of the memory into the ACC 79. The address part of the instruction remaining in the MBR 75 is transferred to the SAR 74, then a read command is issued to the memory, and after a while, the data obtained in the MBR 75 is transferred to the ACC 79 to complete the instruction.
As another example, we will show how a conditional branch instruction, which frequently appears in the flowcharts described later, is executed. If it is desired to make a conditional branch by determining the state of a certain input port (assumed to be port A), the contents of port A are read to the MBR 75 in the switch cycle, as in the case of the above example. It is assumed that the bit of the A port is in the most significant bit of the memory. Now INR73
If an LDA instruction is included to store the contents of the memory in the ACC 79, the contents of the A port are transferred to the ACC 79 in the same way as in the above example.
Subsequently, the PC 76 instructs the address to be executed next, and the instruction is stored in the MBR 75 in exactly the same manner. Now, if INR73 contains an instruction (ROL instruction) to shift the most significant bit of ACC79 to the carry flag of CCR82, in the next execution cycle,
This means that the status of the A port (“0” or “1”) is stored in the carry flag. Next, in the same way, the state of the carry flag is determined, and if the carry flag is "1", the program branches, and if not, it executes an instruction (BCS instruction) to directly execute the next program. can be accomplished. In the latter example, LDA, ROL
Although three instructions, ie, and BCS instructions, were used, desired control can be performed by arbitrarily combining dozens of types of instructions in this way.

In the flowcharts described later (see Figures 11 to 16), we will explain how to use each block shown in Figure 5 to execute the program at the machine language level. Although not shown, transfer commands, addition and subtraction, etc. in the program can be easily implemented using known methods.

FIGS. 6 to 10 show display modes on the photographic information display device 39, respectively.
The display device 39 is formed of a well-known liquid crystal display board, and includes a shutter time electrode of "1" to "2000" and a rectangular shape arranged in a straight line in the horizontal direction directly above the shutter time electrode. The bar display segment electrode has a bar display segment electrode, diamond-shaped point display segment electrodes arranged horizontally in sequence immediately above the bar display segment electrode, and "SPOT" and "MEMO" electrodes, respectively. ing. Each electrode is made of a transparent electrode, and the display device 39 is of a light transmissive type. The above segment electrode for bar display is for displaying the shutter time value corresponding to the average brightness value in average photometry mode, or the shutter time value corresponding to the additive average value of spot brightness values in spot metering mode. The point display segment electrode is for displaying the shutter time value corresponding to each spot brightness value in the spot photometry mode. Also, “SPOT”
The electrode is used to indicate that the camera is in spot photometry mode, and the "MEMO" electrode is used to display that it is in EE lock mode.

As mentioned above, each of the above electrodes has one
Memories corresponding to pair 1 are allocated in the DRAM 85 (see Fig. 5), and a voltage is selectively applied to the electrodes according to the contents of these memories to display the shutter speed index or to calculate the shutter speed in seconds. Bar display, point display, etc. of the current value T _v are now available. Therefore, all displays on the display device 39 are latched displays, and once a certain segment is displayed, the display of that segment will not be cleared unless the contents of the corresponding memory are changed.

Note that in the flowcharts (Figures 11 to 16) described below, clearing of the memory that is performed before displaying to update the display is not specifically specified, but this is because the basic display is a bar display or a point display. It's done in the program. Furthermore, since the contents of the memory are updated at a high speed of several tens of microseconds, even if a segment that does not require display change is momentarily cleared, the display will not flicker at all.

As described above, the camera 10 of this embodiment is configured.

Next, before entering into a description of the operation of this camera 10, the photographing mode in the camera 10 of this embodiment will be outlined. First, the photographing modes of the camera 10 are roughly divided into an average metering mode and a spot metering mode. In the average photometry mode, photography is performed based on an average luminance value obtained by photometering a relatively wide area of the subject. The spot metering mode is a shooting mode that is selected by pressing the spot input button 14 in the average metering mode, and the spot brightness value is not input when the spot input button 14 is pressed for the first time. Instead, only the shooting mode is switched. Then, by operating the spot input button 14 for the second and subsequent times, the spot brightness values are input in sequence and the shutter is released, taking a photo at the exposure level determined based on the average value of the spot brightness values. It is beginning to be practiced. In both the average photometry mode and the spot photometry mode, an EE lock mode can be selected.
In this EE lock mode, after the camera 10 has been powered on and taken at least once, the EE lock operation knob 13 (see Figure 1) must be turned to "EE."
EE lock switch according to the “LOCK” indicator
This is a shooting mode that is selected by closing SW ₃ (see Figure 4), and the number of subsequent shots at the same exposure level as the one taken immediately before closing EE lock switch SW ₃ . This is a shooting mode that allows you to take pictures even with the camera.

Next, the operation of the camera 10 of this embodiment will be explained with reference to the flowcharts shown in FIGS. 11 to 16. In addition, in the interpretation of the flowchart, MX (X is arbitrary) is the memory address, (MX) is the memory contents of the MX address, and "←"
Assume that each represents a transfer. Therefore, for example, "MA1←0" means to store "0" in the memory at address MA1, and "MA1←
(MA3)'' means to transfer the contents of the memory at address MA3 to the memory at address MA1.

First, when power is applied to the camera 10, an operating voltage is supplied to the electric circuit shown in FIG. 4, and each part of the circuit enters an operating state. In the CPU 50, the program starts from the mode determination flowchart shown in FIG. 11, and first initial settings of various flags and memory are performed in the subroutine SUBI. Here, as shown in FIG. 15, in order to initialize the spot mode detection flag MA1, "0" is stored in the flag MA1. Next, in order to initialize the spot input detection flag MA2, "0" is stored in the same flag MA2. Next, the spot input number memory M
6, write “-1” to the same memory M6.
is stored. Next, set the EE lock detection flag.
To initialize ME1, "0" is stored in the flag ME1. Then, returning to the flowchart for mode discrimination shown in FIG. 11,
Subsequently, in order to initialize the EE lock enable flag ME2, "0" is stored in the flag ME2. This EE lock enable flag ME2 is a flag that prevents the EE lock mode from being selected unless the camera 10 is photographed at least once after the power is turned on.

Next, it is detected whether or not the EE lock operation knob 13 is operated in response to the "CLEAR" index by determining I4=1. If the nozzle 13 is operated and the clear switch SW ₄ is turned on, I4 = 1, so this judgment is YES (hereinafter, on the flowchart, the branching direction of YES is referred to as Y).
Indicated by ), move to subroutine SUBI, clear various flags and memory, and then return to EE.
The lock enable flag ME2 is determined.
Also, if the knob 13 is not operated and the clear switch is
If SW ₄ is off, I4=0, so I4=
1 is passed as NO (hereinafter, in the flowchart, the branching direction of NO is indicated by N), and immediately the EE lock enable flag ME2 is determined.

To determine the EE lock enable flag ME2,
This is done by determining (ME2) = 0, and (ME2) =
If it is 0, it means that no shooting has been done after the power was turned on, so the judgment is passed with a yes and the next EE is started.
The process skips the lock mode detection (determination of I3=1) and enters the determination of the average photometry mode (determination of I1=1).

(1) Now, assuming that you have not operated any of the various operation members after powering on the camera 10, the camera 1
0 is average photometry mode. That is, since the average metering mode selection switch SW ₁ is off and the spot input switch SW ₂ is off, the flow is I1 = 1.
and I2=1 are both passed as no, and the spot input detection flag MA2 is set to “0”.
After storing and initializing , the judgment of (MA1) = 1 is passed as no. Therefore, the program flow branches to the average photometry mode flowchart shown in FIG. 12 through -. Here, first, it is determined whether or not it is in the EE lock mode by determining (ME1) = 1, but since it is not currently in the EE lock mode, this determination is passed as NO, and then the display device 39
A basic display is performed. This basic display, as shown in FIG. 6, is a display of a shutter speed index of "1" to "2000". Next, the average brightness value BV1 is input to the brightness value storage memory M1. The input of this average brightness value BV1 is the average brightness value BV1 in the electric circuit shown in FIG.
Multiplexer MPX ₁ to voltage corresponding to BV1
The average brightness value BV1 of the digital quantity is input to the input port I7 through a successive approximation type A-D conversion circuit consisting of a D-A converter 58 and a comparator _A6 . It can be done.

After inputting the average brightness value BV1, the process moves to the subroutine SUB shown in FIG. 16, where the film sensitivity value SV, correction value CV and aperture value AV are entered.
are respectively input in the same manner as the average brightness value BV1, and are stored in the film sensitivity value storage memory M.
2, stored in the correction value storage memory M3 and the aperture value storage memory M4, respectively. After this, when returning to the flowchart of the average metering mode shown in Fig. 12, the shutter second value TV
Apex operation ((M1) + (M2) + (M3) -
4M4)) is performed, and the calculation result value is stored in the shutter seconds value storage area M5. continue,
Shutter second time value TV determined by the above calculation
(M5) is displayed as a bar on the display device 39 (see FIG. 6).

Next, it is detected whether or not the shutter release has occurred by determining I5 = 1. If it is not a shutter release, this determination is passed as NO, and after executing the interval, through -, the 11th
Returning to the flowchart of mode determination shown in the figure.
Therefore, unless the shutter release button 11 is pressed or other operating members are operated, the flow loops along the previously described path. Note that the above-mentioned interval is for adjusting the time so that one execution time of the program is about 100 ms, and can be easily executed by program operation in microcomputer processing.

If the shutter release button 11 is pressed,
When release switch SW ₅ is closed,
In the average photometry mode flowchart shown in Fig. 12, the judgment of I5=1 is passed as YES, and -
The process branches to the shutter release flowchart shown in FIG. Here, first, "1" is stored in the output port O4, and in the electric circuit shown in FIG. 4, the transistor _Q7 is turned on, and the trailing curtain locking magnet _Mg1 is energized to hold the shutter trailing curtain. . Next, the contents (M1) of the brightness value storage memory M1 are stored in the brightness value storage memory M10, and the average brightness value BV1
will be saved. This will be the next shoot
Since this may be performed in EE lock mode, the average brightness value BV1 at the time of shooting is set in advance.
It is done to remember. Next, save the previously input spot brightness value (MPN←
(MBN), N=1 to n), storage of spot mode detection flag MA1 (MA3←(MA1)),
The number of spot inputs (MC1←M6) is sequentially saved, but these are meaningful only when the current shooting is in the spot metering mode, and are irrelevant in the current case, which is the average metering mode. Next, timer count setting memory MT
, the apex-calculated shutter seconds value TV
(M5) is stored. Subsequently, it is determined whether the trigger switch SW ₆ has been closed and exposure has started based on the determination of I6=1, and when exposure has started, this determination is made YES and the timer count program is entered. Here, the contents (MT) of the timer count setting memory MT mentioned above are counted down sequentially, and the contents (MT) of the memory MT are
When becomes "0", the determination of (MT)=0 is passed as YES, and "0" is then stored in the output port O4. As a result, in the electric circuit shown in FIG. 4, the transistor _Q7 is turned off, the trailing curtain locking magnet _Mg1 is demagnetized, and the shutter trailing curtain starts running. The exposure is then completed. After this, set the EE lock enable flag.
The flag ME2 indicates that "1" has been stored in ME2, that a photograph has been taken at least once after the power was turned on, and that the EE lock mode can now be selected.
It is stored in 2. Next, "0" is stored in the spot input detection flag MA2, and the state is returned to the state where there is no spot input, but this only has meaning when the current shooting is in the spot metering mode, and is in the average metering mode. It's not relevant in this case. Next, by determining (MA1) = 1, it is determined whether the current shooting was performed in average metering mode or spot metering mode, and since it is currently in average metering mode,
The result of the determination is NO, and "-1" is stored in the spot input number memory M6 and initialized.
In addition, in the case of spot metering mode,
(MA1) = 1 is passed with a yes, and the memory M
“0” is stored in 6. Next, the interval instruction is executed. This interval is
Since several tens of milliseconds are required until the movable reflection mirror 31 is lowered after exposure is actually completed and the next photometry can be started, this program is designed to delay this. The program flow then returns to the mode determination flowchart shown in FIG. 11 through - and loops again through the previously described path.

Further, even if the average photometry mode switching button 15 is pressed from the spot photometry mode, the camera 10 is set to the average photometry mode. In this case,
In the mode discrimination flowchart shown in Fig. 11, I1=1 when the average photometry mode selection switch SW ₁ is turned on, so the program reads I1=1.
1 is passed as YES, spot mode detection flag MA1 and spot input detection flag are set.
After initializing by storing "0" in MA2, the process branches to the average photometry mode flowchart shown in FIG. 12 through -. Therefore, as in the case above, the flow loops and
The shutter time value TV based on the average luminance value BV1 is displayed as a bar on the display device 39 (see FIG. 6). Furthermore, when the pressing operation of the average photometry mode switching button 15 is released, since the average photometry mode selection switch _SW1 is a self-resetting switch, I1≠1, but the content of the spot mode detection flag MA1 becomes "0" once. Therefore, from then on, just as in the case described above, the determination of (MA1)=1 is passed as NO, and the process branches to the flowchart of the average photometry mode shown in FIG. 12 through -.

(2) Next, operate the EE lock operation knob 13 from the average metering mode to set the index to "EE."
LOCK” indicator, it becomes EE lock in average metering mode. In this state, it is assumed that at least one photograph has been taken after the power is turned on, and the content of the EE lock enable flag ME2 (ME2) is "1". Therefore, in the mode determination flowchart shown in FIG. 11, the determination of (ME2)=0 is passed as NO, and then the determination of I3=1 is entered. In addition,
If shooting has not been performed since the power was turned on, operate the EE lock operation knob 13.
Even if the index = corresponds to the "EE.LOCK" index, the EE lock enable flag ME2 remains "0", so the next determination of I3 = 1 is skipped and the EE lock mode is not selected.
The determination of I3=1 is to detect whether the EE lock operation knob 13 has been operated and the EE lock mode selection switch SW ₂ has been closed, and the EE lock mode selection switch SW ₃ is currently on. Therefore, this judgment is passed with a yes, and then "1" is stored in the EE lock detection flag ME1, and the fact that the EE lock mode is set is stored in the flag ME1. Therefore,
After this, remove the operating force from the EE lock operation knob 13 and turn the EE lock mode selection switch SW _3.
Even if the device turns off due to its own habits, the state of EE lock mode is maintained. Subsequently, the contents (MC1) of the spot input number storage memory MC1 for EE lock are transferred to the spot input number memory M6, and the spot mode detection flag is also set.
The contents of the mode memory flag MA3 (MA3) for EE lock are transferred to MA1, but these have meaning only when the previous shooting was in spot metering mode, so if the previous shooting was in average metering mode. It doesn't really matter in this case.
However, even if EE lock is selected in average metering mode, if the previous shot was taken in spot metering mode, the next shot will be taken using EE lock in spot metering mode. will be described later, but since it is the same as when the EE lock is set in the spot metering mode, a detailed explanation will be omitted.

Next, we enter the judgment of I1=1 and I2=2,
Normally, the EE lock operation knob 13, the spot input button 14, and the average metering mode switching button 15 are not operated at the same time, and switches SW ₁ and SW ₂ are considered to be off, so each of these judgments is passed with a negative result. After storing “0” in the spot input detection flag MA2, (MA1) =
After passing through the determination No.1, the process branches to the average photometry mode flowchart shown in FIG. 12 through -. Here, it is detected whether or not it is in EE lock mode by determining (ME1) = 1, but since it is currently in EE lock mode, this determination is passed with a yes, and then the display device 3
A basic display at 9 is performed. This basic display is “1” to “2000” as shown in Figure 7.
Display of shutter speed index and “MEMO”
and the display of indicators. Next, the contents (M10) of the brightness value storage memory 10, that is, the average brightness value BV1 at the time of the previous photographing, are restored to the brightness value storage memory M1. This is done to ensure that the photograph is taken at the same exposure level as the previous photograph. From then on, the subroutine is similar to the normal average metering mode described in (1) above.
The film sensitivity value SV, correction value CV, and aperture value AV are input at SUB, and after apex calculation of the shutter second value TV (M5) is performed, this is displayed as a bar. (See Figure 7). In other words, in the case of EE lock mode, the average luminance value
BV1 is not updated, the average brightness value BV1 taken immediately before EE lock is used as is, and only the film sensitivity value SV, correction value CV and aperture value AV are updated. In other words, photography is always performed at a constant exposure level. When the shutter release button 11 is pressed, the shutter is released in the same manner as in the normal average photometry mode described in (1) above.

(3) Next, the operation in spot metering mode will be explained. The spot photometry mode can be selected by pressing the spot input button 14. When the spot input button 14 is pressed, the spot input switch SW 2 is turned on and the first spot input switch SW ₂ is turned on.
In the mode determination flowchart in Figure 1,
The judgment of I2=1 will be passed with a yes. Then, based on the judgment of (ME1) = 1, it is detected whether or not it is in the EE lock mode.
Assuming that we are not currently in EE lock mode, we pass this judgment with a no, and by the judgment of (MA2) = 1,
A determination is made as to whether or not a spot brightness value is being input. If spot input is detected only by turning on spot input switch SW ₂ , it will be determined that a spot input has been made every time the flow cycles.To avoid this, it is necessary to perform a spot input operation once. Once done,
Next, after confirming that the spot input switch _SW2 has been turned off, it is necessary to detect the spot input again. The spot input detection flag MA2 is a flag for this purpose.
Before switching to spot metering mode, it is initialized to "0", so the program first sets (MA2) =
Judgment number 1 will pass with a no. continue,
"1" is stored in each of the spot detection flag MA1 and the spot input detection flag MA2, and it is remembered that the spot metering mode has been selected, and spot input will not be performed unless the pressure on the spot input button 14 is once released. Remember what you should not do. and,
The program branches to the spot metering mode flowchart shown in FIG. 14 through -.

In the flowchart for spot metering mode,
First, basic display is performed on the display device 39. This basic display, as shown in Figure 8,
These are the display of the shutter speed index from "1" to "2000" and the display of the "SPOT" index. next,
The spot input number memory M6 is counted up (M6←(M6)+1). Memory M6
is initialized to "-1" when the spot photometry mode is selected, so it becomes "0" and the next determination (M6)=0 is passed with a yes. This is 1 of the spot input buttons 14.
This is so that the second operation only switches the photographing mode to the spot metering mode and does not input the spot luminance value. Subsequently, the spot brightness value BV2 is input to the spot brightness value storage memory M7, and the subroutine SUB
The film sensitivity value SV, correction value CV, and aperture value AV are respectively input by . and,
The shutter time value TV (M8) is apex-calculated and, as shown in FIG. 8, is displayed as a point on the display device 39 as the shutter time value of the subject portion currently being photometered. Therefore, the camera 10 is in a state where the photographer can input a spot brightness value while monitoring the exposure level of the photometry section.

Next, it is detected whether the shutter release has occurred or not by determining I5=1, and if it is not the shutter release, this determination is passed through with a "no", and after the execution of the interval, through -, as shown in FIG. Return to the mode determination flowchart. Normally, spot input switch SW ₂ is used for flow 1.
It remains on for longer than the time required for the cycle (approximately 0.1 sec). In the second program flow, the I2 = 1 judgment is passed again with a yes, and this time the (MA2) = 1 judgment is passed with a yes, and through -, the flowchart of the spot metering mode shown in Fig. 14 is reached. It will diverge. Therefore, the spot brightness value BV2 is stored in the spot brightness value storage memory M7 again, and in the same manner, the shutter second value of the subject part currently being photometered is displayed in points.

After this, when the press of the spot input button 14 is released, the spot input SW ₂ turns off by its own habit, so that I2≠1, and in the mode determination flowchart of FIG. 11, the determination of I2 = 1 is passed as NO. It becomes like this. However, during the initial program flow, the spot mode detection flag MA1 was set.
Since we have set "1" in the spot input detection flag M2, we initialize it by storing "0" in the spot input detection flag M2.
The determination of (ME1)=1 is passed as NO, and the process branches to the flowchart of the spot photometry mode shown in FIG. 14 through -.
Therefore, the subsequent flow of the program is the same as when the spot input button 14 had been pressed.

Next, when the spot input button 14 is pressed again to close the spot input switch _SW2 , the 11th
In the flowchart for mode determination in the figure, I2
Pass the determination of =1 with YES, pass the determination of (MA2) =1 with NO, and set the spot mode detection flag MA1 and the spot input detection flag.
After storing “1” in each MA2, −
The process branches to the flowchart of the spot photometry mode shown in FIG. Here, after the basic display is performed, the count up of the spot input number memory M6 (M6←(M6)+1)
is performed, and next time the contents of memory M6 (M
6) becomes “1”. Therefore, the program is
The next judgment (M6) = 0 can be passed with no, and the spot brightness value is stored in the brightness value storage area MBn.
BV2 is stored. Here, n in the area MBn means the content (M6) of the memory M6, and since (M6)=1 now, the spot brightness value V2 is stored in the memory at address MB1. Next, the film sensitivity value is set using the subroutine SUB.
The SV, correction value CV, and aperture value AV are input, and then the apex calculation of the shutter second value TV corresponding to the spot brightness value BV2 is performed, and this is stored in the shutter second value storage area.
Stored in MSN's corresponding memory. and,
This point display of the shutter time value TV is performed on the display device 39. Next, calculate the average of the shutter seconds value TV _o 〓 ^N=1 (MSN)/
n) is performed and stored in the shutter time value storage memory M5, but since there is currently only one spot input value, the spot brightness value BV2 is
is the average value itself. Subsequently, this average value is displayed as a bar on the display device 39. Thereafter, the spot brightness value BV2 is stored in the spot brightness value storage memory M7, and from then on, the shutter second value of the subject part currently being photometered is displayed in the same way.

Next, it is detected whether or not the shutter release has occurred by determining I5 = 1. If it is not a shutter release, this determination is passed as NO, and after the execution of the interval, the 11th
The process returns to the mode determination flowchart shown in the figure. In the program flow from the second time onwards, I2
Pass through the judgment of =1 with a yes, pass the judgment of (MA2) =1 with a yes, and through -, the 14th
The branching to the flowchart of the spot photometry mode shown in the figure is the same as in the case of the first press operation of the spot input button 14.
Then, when the press of the spot input button 14 is released, the determination of I2=1 is passed as no, and (MA1)=1
Pass the judgment with yes, and as before, −
Through this, the process branches to the flowchart of the spot photometry mode shown in FIG.

In this way, when multiple spot input buttons 14 are pressed, in the flow of the first program when I2 = 1, the determination of (MA2) = 1 is always passed as NO, and through -, as shown in Fig. 14. The flowchart branches to the spot photometry mode, and the spot input number memory M6 is counted up (M6←(M6)+1). As a result, the contents of memory M6 (M6), i.e., n
increases sequentially, and along with this, the spot brightness values BV2 are sequentially stored in the memory from address MB1 to address MBn in the brightness value storage area MBN. Then, each time a new spot brightness value is input, the apex calculation ((MBN) +
(M2) + (M3) - (M4), N = 1 to n) are redone, and each shutter time value is stored in the corresponding memory (MSN, N = 1) of the shutter time value storage area MSN.
~n) respectively. Each shutter time value TV is displayed as a point on the display device 39 (FIG. 9 shows an example where three spot brightness values are input).
Next, an arithmetic average of each shutter time value TV ( _o 〓 ^N=1 (MSN)/n) is performed, and the result is stored in the shutter time value storage memory M5. Subsequently, this average value M5 is displayed as a bar on the display device 39 (see FIG. 9). From this point on,
The spot brightness value BV2 currently being photometered is input, and the corresponding shutter seconds value TV is displayed as a point. Since this point display moves when the camera 10 is moved or the brightness of the subject changes, it can be distinguished from the point display of the shutter second value corresponding to the previously input spot brightness value.

If the shutter release button 11 is pressed,
Assuming that the release switch SW ₅ is closed, the flow of the program is as shown in the flowchart of the spot metering mode shown in Figure 14, after the determination of I5 = 1 is YES, and then the determination of (M6) = 0 is entered. . This determination is made so that if the shutter release button 11 is pressed while the camera is in spot metering mode but no spot brightness value has been input, the photo will be taken in average metering mode instead of spot metering mode. It is for the purpose of That is, if no spot brightness value is input, the count of the spot input number memory M6 is "0", so
The determination of (M6) = 0 is passed as YES, and the flow of the program temporarily returns to the mode determination flowchart shown in FIG. 11 through -. And here, the spot mode detection flag MA1, the spot input detection flag MA2
After each is initialized to "0", the flowchart of the average photometry mode shown in FIG. 12 is entered through -, and the shutter release is performed in exactly the same manner as in the average photometry mode. In this case, after the shutter release button 11 is pressed, the shutter second time value TV based on average photometry is
After calculating the value, the program enters the shutter release flowchart in Figure 13 again and performs the exposure operation, but since this program processing is performed within a few milliseconds, it has no effect on the actual shooting operation. There isn't.

In the spot metering mode and with the spot brightness value input, press the shutter release button 11.
If is pressed, in the flowchart of the spot metering mode shown in Figure 14, the judgment of I5=1 is YES, the judgment of (M6)=0 is NO, and
The program flow directly enters the shutter release flowchart shown in FIG. Here, the shutter release is performed in exactly the same manner as the shutter release operation in the average metering mode described in (1) above, but in the case of this shooting, the shutter second value is stored in the shutter second value storage area M5. In addition, exposure is controlled by the average value of shutter seconds corresponding to each spot brightness value. In addition, in the case of this shooting, the shooting mode is spot metering mode, so the spot brightness value is saved (MPN←(MBN), N=1 to n), and the spot mode detection flag MA1 is saved (MA3
← (MA1)), save the number of spot inputs (MC1
← (M6)) program becomes meaningful. In other words, there is a possibility that the next shot will be taken with EE lock in spot metering mode.
These values at the time of the current shooting are stored. Also,
After the exposure operation is completed, the spot input detection flag is set.
"0" is stored in MA2, and even if the shutter is released while the spot input button 14 is pressed, it is initialized to the same state as when the spot input button 14 is once released. moreover,
By determining (MA1) = 1, it is determined that the current shooting was performed in the spot metering mode, "0" is stored in the spot input number memory M6, and the previously input spot brightness value is canceled. Ru. The reason why "0" is stored in the memory M6 is because the current shooting mode is the spot metering mode, so the next time the spot input button 14 is pressed, the spot brightness value is input immediately instead of switching the shooting mode. This is so that they may do the same. In addition, the spot input number memory M
As long as the contents of memory M6 are reset to "0", the previously input spot brightness values are managed by the contents of memory M6 (M6), that is, n.
The previously input spot brightness values are canceled without clearing the contents of the brightness value storage area MBN.

(4) Next, from this spot metering mode,
By operating the EE lock operation knob 13 and making the index correspond to the "EE.LOCK" index, the EE lock state can be obtained in the spot metering mode.
In this state, it is assumed that at least one photographing has already been performed, and the content (ME2) of the EE lock enable flag ME2 is "1". Therefore, in the mode determination flowchart shown in FIG.
Pass the judgment of (ME2) = 0 with no, then I3 = 1
enter into the judgment. Then, exit this judgment with a yes, and set the EE lock detection flag in the average photometry mode described in (2) above, as in the case of EE lock.
"1" is stored in ME1, and the contents (MC1) of spot input number storage memory MC1 for EE lock are stored in spot input number memory M6.
1. Mode memory flag for EE lock
The contents of MA3 (MA3) are transferred respectively,
The number of spot inputs and the spot metering mode from the previous shooting are restored.

Next, the judgment of I1=1 is passed with no, and I2=
1 judgment is entered, but whether you pass this judgment with a yes or no, in the end you will pass each judgment of (ME1) = 1 with a yes, and through -,
The process branches to the flowchart of the spot photometry mode shown in FIG. Here, first, basic display is performed on the display device 39. This basic display is as shown in FIG.
Display of shutter speed index of “2000”,
These are the display of the “SPOT” index and the display of the “MEMO” index. Next, the film sensitivity value SV, correction value CV, and aperture value AV are input by subroutine SUB, and then the shutter second value corresponding to each spot brightness value that has been previously input is calculated (( MPN) + (M2) + (M3) -
(M4), N=1 to n) are performed, and the results are stored in the corresponding memories (MSN, N=1 to n) of the shutter time value storage area MSN, respectively. Each shutter time value TV is displayed as a point on the display device 39 (FIG. 10 shows an example where two spot brightness values are input and stored).
Thereafter, as in the case of the normal spot metering mode described in (3) above, the average value of the shutter seconds value TV is calculated, and this is displayed as a bar.
The point brightness value currently being photometered is input, and the corresponding shutter seconds value is displayed as a point (see FIG. 10). When the shutter release button 11 is pressed, as in the case of the normal spot metering mode described in (3) above, the judgment of I5=1 is passed as YES, and through -, as shown in Fig. 13. The flowchart branches to the shutter release flowchart, and an exposure control operation is performed. At this time, the previously input spot brightness values, etc. are saved again, so it goes without saying that it is possible to take photographs under the same exposure conditions any number of times.

In addition, by operating the EE lock operation knob 13,
When that indicator corresponds to the “CLEAR” indicator,
Clear switch SW ₄ is turned on, and in the mode determination flowchart shown in Figure 11, the determination of I4 = 1 is made YES, so that various flags and memory are initialized by subroutine SUB. Become. Therefore, the spot metering mode and the EE lock mode are canceled, and the camera 10 automatically returns to the normal average metering mode.

As described above, according to the present invention, the values stored in the camera are cleared each time a lens is replaced, so that exposure errors due to differences in lens open aperture values can be reliably prevented.

[Brief explanation of drawings]

FIG. 1 is a plan view of a camera showing an embodiment of this invention, FIG. 2 is a side view of the main parts showing the optical system installed in the camera shown in FIG. , a front view of the photometric light receiving device disposed in the optical system shown in FIG. 2, FIG. 4 is an electrical circuit diagram of the camera shown in FIG. 1, and FIG.
Block diagrams showing the internal configuration of the microcomputer as the central processing unit shown in the figure, FIGS. 6 to 10, show the display mode in the photographing information display device shown in FIGS. FIGS. 11 to 16 are enlarged front views, flowcharts showing the programs in the microcomputer shown in FIG. Figures showing examples, and the 20th
21 and 21 are diagrams showing a second example for performing a clear operation, respectively. 1... Camera body, 2... Lens barrel, 10...
...Camera, SW ₄₀ ...Clear switch, 101...
...detection pin, 5a...speed-action lever, 1b...speed-action ring.

Claims (1)

[Scope of utility model registration request] A camera with interchangeable lenses that measures subject light through a photographic lens and stores and stores the measured light values includes a camera body and a detection member provided on the camera body that detects when the lens is removed from the camera body. A camera characterized in that the storage of the photometric value is released in response to the detection operation of the detection member.