JP2884657B2 - camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an automatic exposure state in which an aperture and a shutter speed are automatically set based on luminance information of a shooting area, and a manual in which an aperture and a shutter speed can be arbitrarily set. The present invention relates to a camera including an exposure state switching unit for switching to an exposure state, and an emission control unit for emitting a flash device when a flash emission is required based on the luminance information in the automatic exposure state.

[Conventional technology]

The above-mentioned camera can shoot in an extremely simple procedure by automatically setting the exposure conditions such as the aperture and shutter speed in the automatic exposure state, and in addition, when the subject has low brightness or backlight. By automatically causing the flash device to automatically emit light, it is possible to avoid underexposure, and even a non-skilled person can easily take an image with few failures. By the way, in this kind of camera,
Even when it is determined that the flash photography is unnecessary based on the luminance information, the flash device may be desired to emit light for a special reason, for example, to make the main subject stand up and make a photograph with the background dropped. Conventionally, in order to respond to such a demand, an operation member for always emitting the flash device at the time of exposure is provided regardless of the luminance information of the shooting region, and by operating this operation member in the automatic exposure state, the flash combined shooting is always performed. There are known ones that can do this.

[Problems to be solved by the invention]

However, the conventional camera described above has the following problem.

In other words, it is not so often necessary for a user of this type of automated camera to always perform flash photography regardless of the luminance information described above, and most photography is performed based on the luminance information. Shooting with the flash device emitting light is sufficient only when light emission is required. Nevertheless, the conventional camera, which has a dedicated operation member for expressing less frequent shooting conditions, increases the number of parts and complicates the circuit for controlling the camera operation, resulting in cost reduction. It was to bring up.

An object of the present invention is to provide a camera which can realize a configuration for performing forced light emission in an automatic exposure state in view of the above-mentioned circumstances, in a cost-effective manner.

[Means for solving the problem]

The camera according to the present invention is characterized in that the exposure state switching means switches between an automatic exposure state in which an aperture and a shutter speed are automatically set based on luminance information of a shooting area and a manual exposure state in which the aperture and a shutter speed can be arbitrarily set. Light emitting control means for causing the flash device to emit light when the flash is required based on the luminance information in the automatic exposure state, and always emitting the flash device in the automatic exposure state regardless of the luminance information. A forced light emitting means is provided, and the forced light emitting means is linked so as to be activated by an operation on an operation member for setting a photographing condition in the manual exposure state.

(Operation)

In other words, in order to perform forced flash in the automatic exposure state,
Focusing on the fact that there is an operation member used only in the manual exposure state instead of providing a dedicated operation member, for example, an operation member for changing and setting the aperture and the shutter speed in the manual exposure state, or An operation for an operation member that is not used in the automatic exposure state, such as an operation member for selecting a shooting condition to be changed in a configuration in which a change setting of the aperture and the shutter speed is shared by one operation member. By performing forced light emission in the above, it is not necessary to add an operation member even though a new function is added. In the control device of the camera, it is recognized whether the camera is in the automatic exposure state or the manual exposure state. Therefore, the operation of one operation member causes the camera to perform an operation according to each exposure state. It can be realized very easily only by changing the software without causing the circuit to be complicated.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 and FIG. 3 are schematic structural views of the whole camera according to the present invention. This camera is a camera body (1)
A photographing lens (2) detachably attached to a lens mount (1A) of the camera body (1), and a flash device (3) detachably attached to a hot shoe (1B) of the camera body (1). ).

FIG. 2 shows a state where the taking lens (2) is not attached,
FIG. 3 shows a state where the flash device (3) is not mounted.

(11) is a release button for starting the shooting operation,
(12) to (17) are operation keys for switching the operation mode of the camera and setting photographing conditions.

(12) is a photometry mode switching key. Each time this key is pressed, the brightness value of the detected subject is averaged over the entire photographing range to obtain an exposure value for exposure control << Average photometry mode >> And a <multi-segment metering mode> in which an exposure value for exposure control is obtained using the luminance value of the subject detected for each of the plurality of divided areas of the shooting range.

(13) is an exposure mode switching key. Each time the key is pressed, a "program mode" for obtaining an aperture value and a shutter speed value from an exposure value for exposure control in accordance with a preset program chart. The mode is sequentially switched to "manual mode" for manually setting the aperture value at the time of exposure and the shutter speed value.

(14) is an up / down key for switching between the aperture value and the shutter speed value in the <manual mode>. When the mode setting key (15) is pressed to enter the <aperture change mode>, the up / down key is used. When the aperture value is changed by the operation on (14) and the shutter speed is changed to the "shutter speed change mode" by the pressing operation on the mode setting key (15), the shutter speed value is changed by the operation on the up / down key (14). You.

(16) is a flash mode switching key. Each time the key is pressed, the flash device (3) is activated to perform flash photography, and a flash mode (normal) without using the flash device (3). To "natural light mode" for taking a picture. In the above “light emission mode”, in the case of the “program mode” in accordance with the exposure mode, when it is determined that flash photography is necessary based on the subject brightness determination or the like, the flash device (3)
Is automatically set, and in the case of "manual mode", "forcible light emission mode" is set, in which the flash device (3) is always activated.

When the mode setting key (15) is pressed when the flash mode switching key (16) is switched to the <flash mode> in the <program mode>, the flash mode is set to the "forced flash mode". mode"
And << Automatic flash mode >>. Then, the automatic flash mode is released and the flash mode switching operation is performed only in the program mode in order to perform the forced flash mode in which the flash is always used in combination with the flash mode. The mode setting key (1), which is used only for switching the operation target by the up / down key (14) in the “manual mode” and not exclusively in the “program mode”
By also using 5), the number of parts can be reduced rationally.

(17) is an override key for performing exposure compensation for a combination of an aperture value and a shutter speed value according to a program diagram in << Program Mode >>, (18)
Is a main key, and (20) is a body display unit for displaying photographing information by liquid crystal.

Next, operation control of the camera will be described. Figure 1
FIG. 3 is a block diagram of an internal electric circuit of the camera according to the present invention, and also shows an in-lens circuit (200) of the taking lens (2) and a flash control circuit (300) of the flash device (3).

Reference numeral (100) denotes a CPU for controlling the operation of the camera, which controls the entire operation of the camera system including the devices in the camera body (1), the photographing lens (2), the flash device (3) and the like.

Reference numeral (101) denotes a film sensitivity reading circuit for reading the sensitivity information of the film by bringing a terminal provided in the patrone chamber into contact with the film patrone. (102) is a display circuit,
The body display section (20) and a finder display section (not shown) provided in the finder display photographing information and the like.

Reference numeral (103) denotes a shutter driving unit which opens and closes a shutter (not shown) under the control of the CPU (100). (104)
Reference numeral denotes an aperture driving unit which opens and closes an aperture (not shown) under the control of the CPU (100).

(105) is a photometric circuit composed of an IC, and the light receiving section (106)
Converts the photocurrent output from the light receiving unit (106) in accordance with the amount of the subject light received by the camera into a digital value corresponding to the subject brightness and outputs the digital value to the CPU (100). Note that the light receiving section (10
6) is a pair of light receiving elements (106a) and (106a) each having a different light receiving surface corresponding to two divided areas obtained by dividing the photographing area.
b).

A sync switch (Sx) outputs a sync signal for flash emission to the flash control circuit (300) when the shutter is fully opened. The flash control signal (FLEN) from the CPU (100) is input to the flash control circuit (300). When the flash control signal (FLEN) is at the “L” level, the flash control circuit (300) The flash is emitted in synchronization with the input of a synchro signal accompanying the closing of the synchro switch (Sx).

The in-lens circuit (200) is composed of an IC, has focal length information and open aperture value information specific to the taking lens (2), and transmits such information to the CPU (100).

Reference numeral (107) denotes an automatic focus adjustment circuit composed of an IC. The focus state of the photographing lens (2) is determined using detection information from the focus detection unit (108), and the photographing lens (2) is focused on the subject. In order to perform the focus adjustment operation by moving toward the lens, the driver (109) for the lens driving motor (M) receives the control signal (AM1) for starting the motor operation and the control signal (AM2) for stopping the motor operation. Output. Further, the automatic focus adjustment circuit (107) adjusts the focus of the photographic lens (2) with respect to the subject based on the above-described determination of the focus state or the determination result of the focus state again after the focus adjustment operation driven by the motor. When it is located within a set range near the focus position (this state is called a focus state), the CPU
Set the focus detection signal (AFIN) to (100) to “L” level,
Otherwise (ie, out of focus), it is set to the “H” level.

The CPU (100) includes various switches (S ₁ ) to
Status signal (S ₇₎ is input.

(S ₁ ) is a photometric switch that is closed by pressing the release button (11) at the first stage. When the photometric switch (S ₁ ) is closed, the photometric operation by the photometric circuit (105), and Then, the automatic focusing operation by the automatic focusing circuit (107) is started. (S ₂ ) is a release switch which is closed by pressing the release button (11) at the second stage beyond the first stage. The release switch (S ₂ )
, A series of release operations is started.

(S ₃ ) is a flash mode changeover switch in which closing and opening are sequentially repeated by operating the flash mode changeover key (16). When the switch is closed, “flash mode”, that is, use of the flash device (3) is performed. The mode is a permission mode, and in the open state, it is a "natural light mode", that is, a mode in which use of the flash device (3) is prohibited.

(S ₄ ) is a photometry mode changeover switch in which closing and opening are sequentially repeated by operating the photometry mode switching key (13). >>

(S ₅₎ is a mode setting switch and open sequentially closed in operation for the mode setting key (15) are repeated,
In the <manual mode>, the aperture value is changed by the up / down key (14) in the closed state. In this case, the aperture speed is changed by the up / down key (14) in the open state. When the shutter mode is changed to the "shutter speed change mode" and the "program mode" and the "light emission mode", the shutter mode is switched to the "intensity light emission mode" in the closed state, and returns to the "natural light mode" in the open state.

(S ₆ ) is an up / down switch interlocked with the operation of the up / down key (14), which is normally in the neutral position. In the “manual mode”, the up / down key (14) is pressed to the “up” side. When the up-down key (14) is pressed down to the "down" side, the upper contact (a) in the figure comes into contact with the lower contact (b) in the figure.
Abut.

(S ₇ ) is an exposure mode changeover switch in which closing and opening are sequentially repeated by operating the exposure mode changeover key (13). The manual mode is set in the closed state, and the program mode is set in the open state. .

The CPU (100) is activated in response to the closing of the photometric switch (S ₁ ), and uses the luminance value data from the photometric circuit (105) to control the brightness value for exposure control in accordance with the set photometric mode. Is calculated, and from the luminance value and the distribution of the luminance values in the two divided regions in the photographing region, the << automatic emission mode >>
Then, the necessity of flash photography is determined, and the brightness value is decomposed into an aperture value and a shutter speed value according to the necessity of flash photography and an exposure mode. When the relays switch (S ₂ ) is closed, a series of release operations, such as retracting the mirror and operating the aperture and shutter based on the aperture value and shutter speed value, are controlled, and flash photography is required. If not, the operation of the flash unit (3) is controlled. Hereinafter, the control of each operation described above will be described with reference to the flowcharts of FIGS. 4 to 7.

The flowchart of FIG. 4 shows a main routine for controlling the entire operation of the camera.

When the photometric switch (S ₁ ) is closed and this flow starts, first, port processing for activation and initial value setting of the RAM are performed <# 2>, and the open aperture value [A [# 4] Read information necessary for automatic exposure control and automatic focus adjustment, such as [ _VMIN ], maximum aperture value [A _VMAX ], and focal length value [f].

Next, a control signal is output to the automatic focus adjustment circuit (107) to start the automatic focus adjustment operation <# 6>. Upon receiving the control signal, the automatic focus adjustment circuit (107) performs a focus detection operation using information from the focus detection unit (108), that is, an operation of determining the focus state of the photographing lens (2). On the basis of this, a focusing operation for driving the taking lens (2) so as to be in focus is performed.

Thereafter, a control signal is output to the photometric circuit (105) to start a photometric operation, and digitized luminance value data is read from the photometric circuit (105) <# 8>. Subsequently, a subroutine _<< Average photometric value calculation >> for _{obtaining the} average photometric value [B _VAVE ] using the obtained luminance value data is called <# 10.
>. Details of this subroutine will be described later. Next, a subroutine << multi-segment photometric value calculation >> for obtaining a multi-segment photometric value [B _VS ] is called according to a known algorithm using the obtained luminance value data <# 12>. The algorithm of this subroutine is well known and will not be described in detail.

Next, the photometry mode is determined <# 14>. In the case of << Average photometry mode >>, after substituting the average photometry value [B _VAVE ] as the target luminance value [B _VT ], <# 20>, on the other hand, << In the case of "Multi-segment metering mode", the focus determination signal (AF
IN) to determine whether or not the camera is in focus <# 16>. If the camera is in focus, the previous brightness value is used as it is, and nothing is performed. After substituting the multi-segment metering value [B _VS ] as [B _VT ] <<#
18>, in each case, the flash mode is determined <# 30>.

The in-focus state is determined in the step <# 16> described above, and if the in-focus state is set, the previous luminance value is used as it is. (AE lock). As described later, since << multi-segment photometry mode >> is assumed to be a mode used by a beginner relatively compared to << average photometry mode >>, in << average photometry mode >> of the present embodiment,
AE lock is not performed at the same time as focusing, but it is also possible to do so.

In the case of << light emission mode >>, the exposure mode is subsequently determined <# 32>. As a result, in the case of << program mode >>, the photometry mode is further determined <# 34>. As a result, in the case of the “multi-segment photometry mode”, subsequently, it is determined whether or not the flash photography is necessary according to the distribution of the detected luminance value for each divided area <# 36>. That is, when the luminance is low or when the luminance of the periphery is higher than that of the central part and it is determined that the subject is backlit, it is determined that flash photography is necessary.

Next, in step <# 36>, it is determined whether or not it is determined that flash photography is necessary. <# 38>, and if it is determined that flash photography is not required, << Forced flash mode >> is set. It is determined whether or not it has been performed <# 40>. As a result, in the case of the << automatic light emission mode >>, the process proceeds to the step <# 60>, where the control aperture value [A _V ] and the control shutter speed value [T _V ] and the subroutine << natural light mode exposure calculation >> is called. Details of this subroutine will be described later. It should be noted that even if the result of the determination in the step <# 30> is "natural light mode", the process branches to the step # 60.

After returning from this subroutine, the flash control signal (FLEN) is set to the "H" level, and the routine proceeds to steps <# 62> and <# 70>.

On the other hand, if the result of determination in step <# 40> is << Forced flash mode >> and if it is determined in step ## 36 that flash photography is necessary, <# 50 In step <>, a subroutine << light emission mode exposure calculation >> for obtaining a control aperture value [A _V ] and a control shutter speed value [T _V ] suitable for photographing using flash light is called. Details of this subroutine will be described later. It should be noted that, even if the result of the determination in the step <# 32> is << manual mode >> and the result of the determination in the step <# 34> is << average photometry mode >>, It branches to the step of 50>. After returning from this subroutine, the flash control signal (FL
EN) to “L” level, and proceed to steps # 52 and # 70.

The operation from the step <# 30> to the step <# 70> described above is summarized, and the process proceeds to the step <# 36> for determining whether or not the flash photography is necessary. The operation is performed only when the “program mode” is set as the exposure mode and the “multi-segment photometry mode” is set as the photometry mode in the case of the “light emission mode”.

In other words, if 《Manual mode》 is set as the exposure mode, the flash will always be fired without determining whether or not the flash is necessary. Even if 《Program mode》 is set as the exposure mode, the metering mode If << Average metering mode >> is set as
Unlike the << multi-segment metering mode >>, which is capable of discriminating backlight and the like, so that unskilled people can take pictures even if they are unskilled. Since it is possible to take a picture taking into account the brightness state of the camera, it is determined that the photographer has the intention of flash emission as long as the <flash mode> is set, and the necessity of flash emission is determined. The flash is always emitted with priority given to the photographer's intention.

In other words, in the case of << multi-segment photometry mode >>, depending on the photometry mode, it is possible to selectively perform shooting in which the flash is not fired and shooting in which the flash is required and the flash is automatically fired. On the other hand, in the case of << Average metering mode >>, it is possible to selectively perform shooting without flash emission and shooting with flash emission required.

Therefore, the two photometry modes of the average photometry and the multi-segment photometry are appropriately switched to enable a fine photometry operation. By causing the flash to be automatically fired at the time of backlight or the like, it is possible to shoot with less failures.

In step <# 70>, the determined control aperture value [A _V ]
And control shutter speed value display is performed such [T _V]-focus state flash mode, then, to determine the state of the photometric switch _{(S 1) <# 72>} . Photometric switch (S ₁₎
If the is open, it goes to the standby state,
If the photometry switch (S ₁ ) is closed, then the state of the release switch (S ₂ ) is determined <# 74>. If the release switch (S ₂ ) is open, the flow returns to the step <# 8> to repeat the photometry operation. On the other hand, if the release switch (S ₂ ) is closed, the aperture is narrowed down. 76>, opening and closing the shutter <# 78>, charging the aperture and the shutter <# 80>, and then shifting to the standby state.

The flowchart of FIG. 5 shows a subroutine << calculation of average photometric value >> called in the step <# 10> of the main routine. First, prior to the description of the subroutine, the algorithm of the operation used therein will be described.

Exposure calculation is generally performed using a value based on the APEX method in which luminance information of a subject is logarithmically compressed. The average photometry value [B _VAVE ] when performing average photometry using the brightness value [B _Vi ] by the APEX method from the light receiving elements whose light receiving areas are divided into (N + 1) light receiving areas with different light receiving areas is, for example, , The number of divided regions (N + 1) is “3”, the area of each divided region is [S ₁ ], [S ₂ ], [S ₃ ], and the weight for each divided region is [W ₁ ], If [W ₂ ] and [W ₃ ], Can be obtained by

Since the area [S _i ] of each divided region and the weight [W _i ] for each divided region are known, the product [S _i · W _i ] obtained for each divided region is determined by the weight coefficient [k _i ] Putting the above formula as a general formula, Becomes

Here, the above-mentioned weight coefficient [k _i ] indicates the ratio of the luminance value of each divided area, and if the ratio is correct, an absolute value is not necessary. A value normalized to be: If you use the above formula, Becomes

In general, when performing the average photometric calculation, the brightness value [B _Vi ] obtained for each of the divided regions is substituted into the above equation to obtain the average brightness value [B _VAVE ]. In this calculation, Even in a computer, it takes time to find the power of "2", and the amount of calculation becomes enormous as the number of divisions increases.
There is a possibility that a photo opportunity may be missed due to photometric calculation. Therefore, instead of the above formula, Has been proposed and practiced,
Since it is a rough calculation, it is hard to say that it is an accurate average luminance value. For this reason, in the camera of this embodiment, an average photometric calculation is performed based on the algorithm described below, so that an accurate average luminance value [B _VAVE ] can be obtained while shortening the calculation time.

First, a code [B] obtained by _converting the luminance value [B _Vi ] and the average luminance value [B _VAVE ] of each of the divided regions into integers as follows in order to perform a digital operation.
_{Vi *} , B _{VAVE *} ].

Here, the constant [a] is the number of divisions that divide one stage of the luminance value [B _Vi ], and is “8” when the bit operation is performed by expressing the decimal part with 3 bits. Further, the constant [b] is obtained by converting a coded luminance value (hereinafter referred to as a luminance code value) [B _{Vi *} ] into a positive value with respect to a luminance value [B _Vi ] that can take a value ranging from positive to negative. For example, when the number of divisions [a] is set to “8” as described above with respect to the luminance value [B _Vi ] which normally takes a value in the range of “−10 to 20”. , The offset number [b] is “80”
Becomes By performing the process of the formula, luminance information for each divided region, the "00 _H ~FF _H" integer luminance code values being converted [B _{Vi *]} to.

If you rewrite the above formula using the above formula, Becomes Here, the luminance code value [B _{Vi *} ] is a positive integer, and using the quotient [Mi] of the integer divided by the aforementioned division number [a] and the remainder [Ni], Therefore, if we rewrite the above formula using this formula, Becomes

Now, the largest one of the luminance code values [B _{Vi *} ] obtained by converting the luminance value [B _Vi ] of each divided area is represented by [B
_{Vmax *} ], it can be expressed as B _{Vmax *} = a · Mmax + Nmax from the equation, and the maximum quotient [Mmax] obtained by using this equation is introduced into the above. Can be rewritten.

In the above equation, the maximum quotient [Mmax] can be easily obtained from the equation using the maximum of a plurality of luminance code values [B _{Vi *} ]. Also, in [1/2 ^Mmax-Mi], because it is [Mmax ≧ Mi], term of [1/2 ^Mmax-Mi] mean, [Mmax-Mi] iterations of division by "2" [Mmax-Mi] in binary arithmetic
This can be done by right shifting multiple times.

That is, the calculation by the computer can be executed by shifting the original data to the right by [Mmax−Mi] bits, and the calculation time can be extremely short.

Further, the value of the remaining term [2 ^{Ni / a} ] (hereinafter referred to as a remainder term) is obtained by dividing the remainder [Ni] obtained by dividing the luminance code value [B _{Vi *} ] by the number of divisions [a] into the number of divisions [ a] and the type is the same as the number of divisions [a], which is a little. Therefore, they are stored as a remainder table, and the data is referred to during the calculation by referring to the remainder table. I have to bring it.

As an example, Table 1 below shows a remainder item table when the number of divisions [a] is “8”. Note that [1.0 ≦ 2 ^{Ni / a} <2.0]
Therefore, in order to effectively use the bits of the memory, the remainder term data corresponds to only the value of the decimal part, and "1" is added and used in the program.

Therefore, the operation of the above-described expression is a combination of simple multiplication, addition, and a function operation for obtaining a known natural logarithm, in addition to the above-described bit shift, and thus can be easily and quickly performed. Then, by converting the average luminance code value [B _{Vi *} ] obtained by the expression using the expression, the average luminance value [B _VAVE ] can be obtained. That is, an accurate average luminance value [B _VAVE ] can be obtained in a short time.

In the above description, the maximum quotient [Mmax] is introduced in the conversion from the expression to the expression, but the same operation can be performed using any other quotient [Mx]. When the maximum quotient [Mmax] is used, the operation of [1/2 ^Mmax-Mi ] is performed by shifting right, while any quotient [M
When [x] is used, [1] depends on the sign of [Mx−Mi].
/ 2 ^Mx-Mi ] will be changed to right shift or left shift.

For example, when the minimum quotient [Mmin] is used, [Mmin−
Since Mi ≦ 0], the calculation of [1/2 ^Mmin-Mi ] is always performed by left shift. However, in such an average photometric calculation by the APEX method, since the calculation is performed using logarithmically compressed data, the obtained average luminance value [B _VAVE ]
Always goes to the side of the maximum luminance value [B _Vmax ] instead of the center of the maximum luminance value [B _Vmax ] and the minimum luminance value [B _Vmin ]. Therefore, as described above, the maximum quotient [M _MAX ] is It is more preferable to introduce and perform the operation because the number of shifts can be reduced and the operation time can be shortened.

Now, the subroutine << average photometric value calculation >> based on the above algorithm will be described with reference to the flowchart of FIG. The number of divisions [a] is set to “8”, and 2
The weighting factor [k _i ] standardized in consideration of the light receiving area [S _i ] and the weight [W _i ] for each of the divided regions is 3 /
4 "and" 1/4 ", and their weighting factors [k _i ]
Are stored in the weight coefficient table as weight coefficient data.

The luminance value data read from the photometry circuit (105) in step <# 8>, which is a step before this subroutine is called, is based on the APEX method, and the integer part 5 bit decimal part 3
It is bit digital data.

When this subroutine is called, first, a maximum value [B _Vmax ] is selected from a plurality of obtained luminance values [B _V0 , B _V1 ] <# 102>, and then, based on the above-described equation, After converting the maximum luminance value [B _Vmax ] to the maximum luminance code value [B _{vmax *} ], the maximum quotient [Mmax], which is an integer part divided by “8” of the division number [a], is obtained <# 104>. Subsequently, the 16-bit addition register (DE) is reset to “0000 _H ” <# 106>, and the counter (i) of the cumulative operation loop is set.
Is reset to “0” <# 108>.

Next, the operation enters a cumulative operation loop, and first,
Based on the equation, the obtained luminance value [B _Vi ] is converted into a luminance code value [B _{Vi *} ], and then the integer quotient [Mi] divided by “8” of the division number [a] and the remainder [N _I ] <# 112>.
Then, according to the value of the remainder [N _I ], Table 1
<# 114> is obtained from the remainder item data (REMD) from the remainder item table indicated by <1>, and "1" is added to the remainder item data (REMD) to obtain the original value (REMV) of the remainder item <# 116>. .
Then, multiply it by “8000 _H ” to adjust the number of bits,
The integer part 1-bit decimal part 15-bit data is set in the bit operation register (HL) <# 118>.

Subsequently, after the data in the operation register (HL) is divided by “4” which is a common denominator of the weighting coefficient [k _i ] for standardization of the weighting coefficient <# 120>, the cumulative operation loop counter ( According to the value of i), the weight coefficient data (WEID), which is the numerator of the weight coefficient [k _i ], is extracted from the weight coefficient table described above <# 122>, and the weight coefficient data (WEID) is stored in the arithmetic register. (# 124) is multiplied by the data in (HL) and stored in the operation register (HL) again.

Next, the maximum quotient [Mmax] obtained in <# 104> and <# 112>
After shifting the data in the operation register (HL) to the right by the number of bits corresponding to the difference from the quotient [Mi] found in << 12
6> The data in the operation register (HL) is added to the addition register (DE) <# 128>. Thereafter, the accumulative operation counter (i) is incremented by <# 128>. If it is determined that the accumulative operation counter (i) exceeds the set value and the accumulative operation has been completed for all of the divided areas, <# 142.
>, If not, return to the step <# 112> and repeat the above accumulation operation <# 132>.

At the time of exit from the accumulation operation loop, the data in the addition register (DE) is equivalent to the antilogarithm part of the logarithmic term in the above-mentioned equation.

In step <# 142>, the data set in the operation register (HL) in step ## 118 has been multiplied by "8000 _H " as a result of adjusting the number of bits. It is necessary to divide the data in the register (DE) by “8000 _H ”, but it is easier to make the integer an antilog in the subsequent logarithmic operation. Is obtained by subtracting the logarithm of "8000 _H " with "2" base from the logarithm of "2" base of the data of "2" and stores it in the result register (C).

Next, the data in the result register (C) is
Digit alignment is performed so that B represents the term of "1/8" which is the reciprocal of "8" which is the number of divisions [a] of the original data <# 14
4>. In other words, this digit alignment is to set the LSB of the data stored in the result register (C) to "1" when the operation result in the step of ## 142 is, for example, "1/8". , Which means that the original calculation result is multiplied by the number of divisions [a]. Therefore, the data in the result register (C) after the digit alignment is obtained by multiplying the logarithmic term in the above-mentioned equation by the number of divisions.

Therefore, next, the following equation, which is obtained by modifying the equation using the above equation, _Is used to determine the average brightness value [B _VAVE ] by the APEX method <# 146>, and then the process returns to the original routine.

The flowchart of FIG. 6 shows a subroutine << flash emission mode exposure calculation >> called in step <# 50> of the main routine described above.

When this subroutine is called, first, the film sensitivity information read by the film sensitivity reading circuit (101) is input <# 202>, and the film sensitivity information is converted into an APEX type film sensitivity value [S _V ]. <# 204> Then, the exposure mode is determined <# 206>.

When the exposure mode is << Program Mode >>, the control exposure value [E _V ] is obtained from the target brightness value [B _VT ] and the film sensitivity value [S _V ] <# 208>, and the maximum flash synchronization speed value [T _VX] ] was used as a control shutter speed value [T _V] <# 2
10> Find control aperture value [A _V ] by subtracting control shutter speed value [T _V ] from control exposure value [E _V ] <# 21
2>. Subsequently, the obtained control aperture value [A _V ] is checked and <# 214, 216>. _If the aperture value is smaller than the minimum aperture value [A _VMIN ], that is, the open aperture value, the minimum aperture value [A _VMIN ] is set to the control aperture value [A _VMIN ]. and a _V] <# 218>, the control aperture value [a _V] is the maximum diaphragm value [greater than a _VMAX] maximum diaphragm value [a _VMAX]
Is set to the control aperture value [A _V ] <# 220>, and the process returns to the original routine.

On the other hand, in the case of <# 206> result of the discrimination at the step of "manual mode", to determine the state of the mode setting switch _{(S 5) <# 230>} . A mode setting switch (S ₅₎ is open a long Invite "shutter speed change mode", the flow proceeds to <# 240> following steps, whereas, if the mode setting switch (S ₅₎ is a closed state "stop Change mode >>, and proceed to the steps following <# 260>.

Go to <Shutter speed change mode><# 24
0> In the following step, the up-down switch (S ₆₎
Check the status of the two input ports (IP ₅ ) and (IP ₆ ) related to <# 240, # 242>, and set the input port (IP ₅ ) to “L” level and the up / down key (14) to the down side if it is the the determined operation proceeds to <# 254> following steps, whereas, if it is determined that an input port (IP ₆₎ is up-down key "L" level (14) is operated in the up-side <# twenty four
4> continue with the following steps, any of the input ports (IP _5),
If (IP ₆ ) is not at the “L” level, the process proceeds to the step of ## 280.

In step <# 244>, the set shutter speed value [T _VS ] is incremented, and then the set shutter speed value [T _VS ] is checked, and <# 246>, the set shutter speed value [T _VS ] is synchronized. If it exceeds the maximum speed value [T _VX ], the tuning maximum speed value [T _VX ] is set to the set shutter speed value [T _VS ], and then the process proceeds to steps ## 248 and # 280.

On the other hand, in the step <# 254>, the set shutter speed value [T _VS ] is decremented, and then the set shutter speed value [T _VS ] is checked, and then <# 256>, the set shutter speed value [T _VS ] _If is smaller than the controllable minimum shutter speed value [T _VMIN ], the minimum shutter speed value [T _VMIN ] is set to the set shutter speed value [T _VS ], and then the process proceeds to steps <# 258> and <# 280>. .

Also, proceed to <Aperture Change Mode><#260> In the following steps, the up-down switch (S ₆ )
Check the status of the two input ports (IP ₅ ) and (IP ₆ ) related to << 260, # 262>, the input port (IP ₅ ) is at the “L” level and the up / down key (14) is on the down side If it is determined that the input port (IP ₆ ) has been set to “L” level and the up / down key (14) has been operated to the up side, it is determined that <# 274>. 26
4> continue with the following steps, any of the input ports (IP _5),
If (IP ₆ ) is not at the “L” level, the process proceeds to the step of ## 280.

In the step <# 264>, the set aperture value [A _VS ] is incremented, and then the set aperture value [A _VS ] is checked. <# 266>, and the set aperture value [A _VS ] becomes the maximum aperture value [ if beyond the a _VMAX], set the maximum aperture [a _VMAX] aperture [a _VS] and then after <# 268>, the process proceeds to step of <# 280>.

On the other hand, in the step <# 274>, the set aperture value [A _VS ]
The decrements, then check the aperture value setting _{[A VS] <# 276>} , is smaller than the set aperture value [A _VS] is the minimum aperture value [A _VMIN], minimum aperture value [A _VMIN] Is set to the set aperture value [A _VS ], and the process proceeds to steps ## 278 and # 280.

In the step # 280, the set aperture value [A _VS ] is set to the control aperture value [A _V ], and then the set shutter speed value [T
_VS ] as the control shutter speed value [T _V ] <# 282
> Return to the original routine.

The flowchart of FIG. 7 shows a subroutine << natural light mode exposure calculation >> which is called in step <# 60> of the main routine described above.

When this subroutine is called, first, the film sensitivity information read by the film sensitivity reading circuit (101) is input <# 302>, and the film sensitivity information is converted into an APEX type film sensitivity value [S _V ]. <# 304> Then, the exposure mode is determined <# 306>.

When the exposure mode is << program mode >>, the control exposure value [E _V ] is obtained from the target luminance value [B _VT ] and the film sensitivity value [S _V ] <# 308>, and the control exposure value on the lower luminance side in the program diagram is obtained. Bending point (on the lower luminance side than this bending point, the control shutter speed value [T _V ] changes according to the luminance value while the control aperture value [A _V ] remains at the minimum aperture value [A _VMIN ]. On the high-luminance side from the bending point, the control aperture value [A _V ] and the control shutter speed value [T _V ] are calculated by the following equations.
Is calculated. )) And the difference [△ E _V ] between the control exposure value [E _V ] and the luminance value [E _VH ] is determined <# 310>, and the sign of the difference [E _V ] is determined <# 312>. .

When the difference [△ E _V ] is negative or “0”, that is, when the luminance is lower than the bending point, the minimum aperture value [A _VMIN ]
Is set to the control aperture value [A _V ], and then the process proceeds to steps ## 314 and # 322. On the other hand, when the difference [△ E _V ] is positive, that is, when the luminance is higher than the bending point, based on an arithmetic expression representing a program line, A _V = A _VMIN + △ E _V / 2, The control aperture value [A _V ] is determined <# 316>. Subsequently, the obtained control aperture value [A _V ] is checked and <#
318>, the control aperture value [A _V] is after the maximum aperture control aperture value [A _VMAX] [A _V] is larger than the maximum diaphragm value [A _VMAX] <# 320>, the <# 322> Proceed to step.

In step <# 322>, the control shutter speed value [T _V ] is obtained by subtracting the control aperture value [A _V ] obtained from the control exposure value [E _V ]. Then, check the sought control shutter speed value _{[T V] <# 324,326>} , greater than the maximum shutter speed value [T _VMAX] maximum shutter speed value [T _VMAX] a control shutter speed value [T _V] and then <# 328>, then the control shutter speed value [T _V] is obtained by a minimum shutter speed value [T _VMIN] minimum shutter speed value is smaller than [T _VMIN] a control shutter speed value [T _V] <#330>, the process returns to the original routine.

On the other hand, in the case of <# 306> result of the discrimination at the step of "manual mode", to determine the state of the mode setting switch _{(S 5) <# 340>} . A mode setting switch (S ₅₎ is open a long Invite "shutter speed change mode", the flow proceeds to <# 350> following steps, whereas, if the mode setting switch (S ₅₎ is a closed state "stop Change mode >>, and proceeds to the steps following <# 370>.

Proceed to <Shutter speed change mode><# 35
0> In the following step, the up-down switch (S ₆₎
Two input ports involved in the (IP _5), to check the state of the _{(IP 6) <# 350,} # 352>, input Podo (IP ₅₎ is up-and-down key in the "L" level (14) to the down side if it is the the determined operation proceeds to <# 364> following steps, whereas, if it is determined that an input port (IP ₆₎ is up-down key "L" level (14) is operated in the up-side <# 35
4> continue with the following steps, any of the input ports (IP _5),
If (IP ₆ ) is also not “L” level, the process proceeds to the step of ## 390.

In step <# 354> increments the set shutter speed value [T _VS], then checks the setting shutter speed value [T _VS] <# 356>, the maximum set shutter speed value [T _VS] is Shutter speed value [T
_VMAX ], the maximum shutter speed [T
_VMAX ] to the set shutter speed value [T _VS ] <# 3
58>, <# 390>.

On the other hand, in the step <# 364>, the set shutter speed value [T _VS ] is decremented, and then the set shutter speed value [T _VS ] is checked, and <# 366>, the set shutter speed value [T _VS ] if There smaller than the minimum shutter speed value [T _VMIN], the minimum shutter speed value [T _VMIN] after the set shutter speed value [T _VS] a <# 368>, the process proceeds to step <# 390>.

Also, advances in the case of "iris change mode" in <# 370> following steps, similarly up-down switch (S ₆₎
Check the status of the two input ports (IP ₅ ) and (IP ₆ ) related to << 370, # 372>, the input port (IP ₅ ) is at “L” level and the up / down key (14) is on the down side If it is determined that the input port (IP ₆ ) has been set to “L” level and it is determined that the up / down key (14) has been operated to the up side, the process proceeds to <# 384>. 37
4> continue with the following steps, any of the input ports (IP _5),
If (IP ₆ ) is also not at the “L” level, the process proceeds to step # 390.

In the step of <# 374>, the set aperture value [A _VS ] is incremented, and then the set aperture value [A _VS ] is checked and <# 376>, and the set aperture value [A _VS ] becomes the maximum aperture value [ if beyond the a _VMAX], set the maximum aperture [a _VMAX] aperture [a _VS] and then after <# 378>, the process proceeds to step of <# 390>.

On the other hand, in the step <# 384>, the set aperture value [A _VS ]
The decrements, then check the aperture value setting _{[A VS] <# 386>} , is smaller than the set aperture value [A _VS] is the minimum aperture value [A _VMIN], minimum aperture value [A _VMIN] Is set to the set aperture value [A _VS ], and the process proceeds to steps ## 388 and # 390.

In step # 390, the set aperture value [A _VS ] is set to the control aperture value [A _V ], and then the set shutter speed value [T
_VS ] as the control shutter speed value [T _V ] <# 392
> Return to the original routine.

The correspondence between the above-described embodiment and words in the claims is as follows. First, "Program mode" corresponds to an automatic exposure state, "Manual mode" corresponds to a manual exposure state, and an exposure mode switching key ( 13) and the CPU (100) that changes the exposure mode in accordance with the operation corresponding thereto constitutes the exposure state switching means. Further, in the automatic exposure state, the CPU (100) for controlling the operation of the flash device (3) so as to cause the flash device (3) to emit light when the flash device needs to emit light based on the luminance information of the photographing area is a light emission control means. Is composed. In addition, the mode setting key (1
5) constitutes an operation member, and the CPU (100) which changes the flash mode in response to an operation on the setting key (15) and sets the mode to "forced light emission mode" constitutes forced light emission means.

(Another embodiment)

 Next, another embodiment of the present invention will be described.

<1> In the above-described embodiment, the configuration for performing the forced light emission in the <program mode> has been described. Alternatively, or in addition to this, detailed description will be omitted. Similarly, in a so-called aperture-priority or shutter-speed-priority exposure state in which the photographer manually sets the other one, the flash device is normally operated automatically, and the flash device is operated at the photographer's will. (3) may be configured to be capable of forcibly emitting light. And, in such a case, as the operation member, the one for setting the photographing condition of the non-priority one,
That is, for example, in the aperture priority mode, an operation member for changing the shutter speed may be used. Therefore, the automatic exposure state in the present invention includes an aperture priority mode and a shutter speed priority mode in addition to a fully automatic program mode.

<2> When the flash device (3) automatically emits light in the automatic exposure state, a criterion for determining whether flash emission is necessary and a configuration therefor can be appropriately changed.
In the case of performing multi-segment photometry, it is not necessary to use the luminance information obtained from the plurality of divided areas to cause the flash device (3) to emit light when the subject is in a backlight state. 3) may be configured to emit light. In this case, a configuration in which only average photometry may be performed instead of a configuration in which multi-segment photometry is possible may be employed.

〔The invention's effect〕

As described above, the camera according to the present invention always causes the flash device to emit light regardless of the brightness information in the automatic exposure state in which the flash device is automatically caused to emit light as necessary based on the brightness information of the shooting area. In doing so, the operation is activated by effectively using the operating members that are not used in the automatic exposure state,
The function can be added advantageously in terms of cost without increasing the number of parts and increasing the complexity of the circuit due to the addition of the operation members.

[Brief description of the drawings]

The drawings show an embodiment of the camera according to the present invention. FIG. 1 is a block diagram of a control circuit, FIG. 2 is a front view, FIG. 3 is a plan view, and FIGS. is there. (3) Flash device, (15) Operation member.

Continuation of the front page Examiner Akiyoshi Sato (56) References JP-A-1-191833 (JP, A) JP-A-1-202719 (JP, A) JP-A-1-289923 (JP, A) (58) Search Field (Int.Cl. ⁶ , DB name) G03B 7/00-7/28 G03B 15/05

Claims (1)

(57) [Claims] An exposure state switching means for switching between an automatic exposure state in which an aperture and a shutter speed are automatically set based on luminance information of a shooting area and a manual exposure state in which an aperture and a shutter speed can be arbitrarily set; In a camera provided with light emission control means for emitting a flash device when a flash is required based on the luminance information in the automatic exposure state, the camera is always forced to emit light regardless of the luminance information in the automatic exposure state. A camera provided with a light emitting means, wherein the forced light emitting means is connected so as to be activated by an operation on an operation member for setting a photographing condition in the manual exposure state.