JPH0332052B2 - - Google Patents

Description

Detailed Description of the Invention Technical Field The present invention enables distance measurement memory for two or more objects having different photographing distances, calculates the intermediate distance between the objects in consideration of the exposure tolerance range of flash light, and The present invention relates to a camera that calculates and controls an aperture value based on an intermediate distance.

Conventional technology In conventional autofocus cameras, the distance is measured and focused on one main subject, and sub-subjects located in front and behind the main subject are used as sub-subjects during strobe photography. It was ignored without any consideration given to the amount of exposure given. As a result, when photographing with a strobe, there was a problem in that the exposure amount of the sub-subject was extremely inappropriate.

For example, when using a conventional FM camera to take flash shots of two subjects at different shooting distances, setting the distance for either subject will result in incorrect exposure for the other, so generally the setting is half the sum of the respective distances. However, in this case, the amount of error in the exposure amount will differ. Now, if you are shooting a subject at 4m and 8m using G No. 32 (ASA/100), in order to obtain the proper exposure for both objects at 4m and 8m, you need to
The aperture must be set to F8 for the 8m type, and F4 for the 8m type. Then, when we calculate the intermediate distance from the above calculation, it is 6m and the aperture is (Go.
No./D32/6=5.333) F5.33.

When shooting the two subjects mentioned above with this setting, the exposure for the 4m object will be +1.2Ev, and the exposure for the 8m object will be -0.8Ev, and the light amount error for each subject will be +
When setting 1Ev and -1Ev, the distance setting must be 5.6 57m. However, under the conditions of flash photography, the subject itself is relatively dark, the visual measurement itself is inaccurate, and furthermore, calculating the intermediate value is troublesome for the camera user, resulting in a missed shot opportunity.

Purpose This invention aims to eliminate the above-mentioned conventional drawbacks, and its purpose is to store distance measurement information of a plurality of objects having different photographing distances, and to take into account the allowable exposure range of flash light. , a predetermined position between these subjects is calculated, and an aperture value is calculated and controlled based on the calculation result, thereby providing a camera that can provide appropriate exposure for each subject.

Embodiments Hereinafter, embodiments of the automatic focusing camera according to the present invention shown in the drawings will be described in detail.

First, before explaining the specific configuration of an automatic focusing camera, a general method for determining the median value D based on the depth of field will be explained with reference to FIGS. 1 and 2. For example, when focusing on an object located at a distance D, the permissible focal range that can be recognized as sharp at the same time, that is, the near limit distance Dmin and the far limit distance Dmax of the depth of field range are calculated by the following formulas. It is required.

Dmin= ^Df2 /{ ^f2 +δF(D-f)(1-η)}
…(1) Dmax=Df ² /{f ² −δF(D−f)(1−η)}
...(2) Here, D...Distance to the subject, f...Focal length of the lens, δ...fxz ¹ = f/1500, F...Aperture value of the lens, η...In normal photography, η≒o, z ¹ = resolution of the eye as it is normally considered on the screen.

Therefore, if the subject is located between the distances Dmin and Dmax, conversely, if you focus at distance D, you will be able to focus on both subjects located at Dmin and Dmax above. can.

This invention is based on the above-mentioned idea, and when the depth of field range is (Dmax-Dmin), the distance D, that is, the median value of the depth of field, is determined as follows.

From the above equations (1) and (2), Dmax−Dmin=f ² /{f ² −δF(−f)(1
−η)} −f ² /{f ² +δF(−f)(1−η) =2Df ² δF(D−f)(1−η)/f ⁴ −{δF(D
−f)(1−η)} ² …(3) By rearranging this equation (3), we obtain 2/D=1/Dmin+1/Dmax …(4), and by further rearranging this, we get =2Dmin Dmax／Dmin＋Dmax...(5) Therefore, by the above formula (5), the nearest distance Dmin and the farthest distance Dmax where each subject is located are calculated.
If this is known, the median value of the depth of field that can encompass it can be found regardless of the lens aperture diameter values F, δ, and η.

Therefore, for example, as shown in Fig. 1, the nearest distance Dmin=2m where the objects are located, and the farthest distance Dmax=
At a position of 4m, the median depth of field is from the above formula (5): =2Dmin・Dmax/Dmin+Dmax=2・2・4/2+4
= 16/6 = 2.666m. In the embodiment described below, this calculation of the median value is performed, for example, by an arithmetic circuit,
Arithmetic expression (5) at that time is given by the arithmetic instruction device.

However, the depth of field d ₁ and d ₂ at the farthest and near sides with respect to the median value in the figure is d ₁ = -Dmin = δF ² / {f ² + δF} ... (6) d ₂ = Dmax - = δF ² / {f ² −δF} ...(7) As is clear from equations (6) and (7), the depth of field d ₁ , d ₂ depends on the aperture diameter of the lens aperture.
varies greatly, and depending on the set aperture value FNo., the farthest and nearest distances Dmax and Dmin may or may not be included in the depth of field d ₁ and d ₂ at that time.

That is, as shown in Fig. 1, for example, when the aperture value is F5 or F6, the limit distance on the far side of the depth of field d ₁ or d ₂ is the farthest distance where the subject is located.
In cases where Dmax and Dmin are equivalent, the aperture value is 5,
At the minimum aperture (diaphragm) side of 6, the depth of field
d ₁ and d ₂ become wider, and the farthest and near distances Dmax and Dmin
On the other hand, at the maximum aperture (open) side of the aperture value FF5, 6, the depth of field _d1 , _d2 becomes narrower,
It does not include the farthest and nearest distances Dmax and Dmin mentioned above.

Therefore, in particular, the depth of field d ₁ and d ₂ are the farthest and nearest distances.
The following methods are used to detect cases where Dmin and Dmax are not included.

In other words, the depth of field based on the set aperture value FNo.
Calculate the ranges d ₁ and d ₂ and check whether the depths of field d ₁ and d ₂ are larger than the distances D ₁ and D ₂ from the median to the nearest distance Dmin and the farthest distance Dmax, respectively. Compare and if d ₁ + d ₂ < D ₁ + D ₂ , then
Shooting at this time is stopped and a warning is issued. In the embodiment described below, the depth of field d ₁ and d ₂ are calculated by a depth of field width calculation circuit, and if the comparison result is d ₁ + d ₂ <D ₁ +D ₂ , then At the same time, a warning is issued by the comparison warning calculation circuit.

Further, FIG. 2 explains how to obtain the median value in consideration of the difference in exposure amount due to the strobe device. In Fig. 2, the distance at which an intermediate exposure amount can be obtained between the respective exposure amounts given to the subject located at the farthest and near distances Dmax and Dmin, that is, the median value D, is determined, and the distance of this median value is determined. The idea is that if you focus on , the difference in exposure between objects located at the farthest and near distances Dmax and Dmin from the median will naturally become equal.

The median value in this case is determined as follows.

In other words, each aperture value F ₁ , F ₂ and its apex value η ₁ , η for a subject located at the farthest distance Dmax, Dmin illuminated by a strobe device having a predetermined guide number (GNo.=K) ₂ is expressed as follows.

F ₁ = K/Dmin…(10) η ₁ = logF ₁ /log√2…(11) F ₂ = K/Dmax…(12) η ₂ = logF ₂ /log√2…(13) 1/2 of the aperture step difference η ₂ − _{η 1} is the distance between the median and the nearest distance Dmin or the farthest distance
Since it is equal to Dmax and the number of aperture stages (=logF−logF ₁ /√2), the following formula holds true.

1/2・logF ₂ −logF ₁ /√2=logF−logF ₁ /√2 …(14) 2logF=logF ₁ +logF ₂ Therefore, logF ² = logF ₁ +logF ² …(15) Here, the above formula (10 ), (12) and F=K/, log(K/D) ² = logK/Dmin・K/Dmax …(16) K ² /D ² =K ² /Dmin・Dmax …(16a) Therefore, = √・…(16b) In the example below, this calculation of the median value is
This is performed by an arithmetic circuit, and at that time, arithmetic expression (16b) is given by an arithmetic instruction device.

Therefore, as shown in Fig. 2, if the subject is at the closest distance Dmin = 2 m and the farthest distance Dmax = 4 m, the exposure will be the middle of the respective exposure amounts at this time. From the above formula (16b), the median value from which the amount can be obtained is =√・=√2×4≒2.83m, and if the shooting lens is adjusted to this median value,
For objects located at the farthest and nearest distances Dmax and Dmin, the exposure amount difference ±α (Ev) from the exposure amount at the median value is equal.

As described above, the median value D based on the depth of field α and the median value D considering the exposure amount difference α are different from each other even if the farthest and nearest distances Dmax and Dmin of the subject are the same. However, the photographer can choose one or the other depending on what is important to him or her.

Next, a specific configuration of an automatic focusing camera using the above principle will be explained with reference to an embodiment shown in FIG.

When the camera operator operates the configuration shown in FIG. 3, the focus memory mechanism 16, release mechanism 1, priority signal buttons 24, 60, 61, 62,
These are the AE and FM selection button 37, the manual cancel instruction button 36, and the out sign cancel instruction circuit 23. Below, the configuration of each part will be explained in sequence along with the interaction with each related part.

First, a case will be described in which focusing is performed in consideration of the depth of field.

In the configuration shown in FIG. 3, in the case of normal photography, the release mechanism 1, gate 2, distance measuring device 3, gate 4, memory circuit 5, first memory cancel circuit 6, arithmetic circuit 7, gate 8, shift register 9 , distance display device 10, comparison warning calculation circuit 11,
Distance width calculation circuit 12, lens drive control start circuit 1
3, a lens drive control completion detection circuit 14, and a shutter drive control start circuit 15.

In the above configuration, the gate 2 is now opened by the operation signal of the release mechanism 1, and the range finder 3 is activated by the signal from the gate 2, and the gate 4 is opened and detected by the range finder 3. The object distance is stored in the storage circuit 5 via the gate 4. In this state, if the release mechanism 1 is returned to the original position, the original position return signal a from the release mechanism 1 activates the first memory cancel circuit 6, and the cancel signal b from the first memory cancel circuit 6 is activated. This cancels the information stored in the memory circuit 5 and prepares for the next operation.

On the other hand, when the operation by the release mechanism 1 is further continued, the calculation start signal C from the release mechanism 1 is transmitted to the calculation circuit 7 for calculating the median value.
At the same time, stored information from the storage circuit 5 is input to the arithmetic circuit 7 via the gate 8 which is in an open state.
is input.

When the calculation start signal C is applied to the calculation circuit 7 and the calculation is started, the calculation circuit 7 applies an information stop signal to the shift register 9, and the signal from the shift register 9 closes the gate 8. The output of information from the memory circuit 5 is stopped.

The median output signal output by the arithmetic circuit 7, that is, the median output signal based on the distance measured by the release mechanism 1, is output from the distance display device 10.
is entered and the calculated median value is displayed. Also,
The median output signal is also input to a comparison warning calculation circuit 11 that calculates the far and near points with respect to the median value, and the comparison warning calculation circuit 11 advances the shift register 9 based on this input signal to sequentially read the stored information. Invoke and import. The comparison warning calculation circuit 11 receives information on the depth of field from the distance width calculation circuit 12, and within this comparison warning calculation circuit 11, the far and near point distances with respect to the median are calculated and stored in the storage circuit 5. It is compared with stored information to determine whether the distance measurement point is within the depth of field. When the object is not within the depth of field, a stop signal is output to the lens drive control start circuit 13 to prevent the lens control operation, and a signal is also output to the distance display device 10 to ensure that the object is within the depth of field. A warning will be displayed to indicate that it is not included.

Note that, as described above, when the distance is measured only by the release mechanism 1, the stored information is == and is not related to the depth of field, so neither a stop signal nor a warning is displayed.

Further, the shift register 9 is incremented sequentially for the comparison in the comparison warning arithmetic circuit 11.
When all operations are completed, the shift register 9 sends a comparison completion signal to the lens drive control start circuit 13.
is output to. This lens drive control start circuit 13
When only the comparison completion signal is input, it starts operating and operates the photographing lens, and controls the photographing lens to the focal point position based on the information on the median value in consideration of the depth of field. When the photographic lens stops, an output signal from the lens drive control completion detection circuit 14 is output to the shutter control start circuit 15, which starts controlling the shutter (not shown).

Next, a case will be described in which one focus memory mechanism 16 and one release mechanism 1 perform distance measurement calculations and control in consideration of the depth of field.

In this case, in addition to the above configuration, a focus memory mechanism 16, a shift register 17, a gate 1
8, memory circuit 19, gate 20, calculation instruction device 2
1. Second memory cancel circuit 22, out signal cancel instruction circuit 23, absolute priority signal circuit 2
4, a memory display circuit 25, a gate 26, a third memory cancel circuit 27, and a gate 28.

In this configuration, first, when the focus memory mechanism 16 is operated, the shift register 17 is activated and the gate 18 is opened, and the focus memory mechanism 16 is operated.
The distance measuring device 3 is activated by the final position signal No. 6, and distance information is stored in the storage circuit 19.

Next, the gates 2 and 4 are opened by the operation of the release mechanism 1, and the distance measuring device 3 is activated by the signal from the release mechanism 1, and the distance measurement information obtained by the operation of the release mechanism 1 is stored in the storage circuit 5. Ru. Note that when the release mechanism 1 is returned to its original position, the first memory cancel circuit 6 is activated as described above.
is activated. However, the memory contents of the memory circuit 19 remain.

Furthermore, when the release mechanism 1 is operated, a calculation start signal C is output to the calculation circuit 7, and calculation of the median value is started. Distance information is input to the arithmetic circuit 7 from the memory circuits 5 and 19 via the gates 8 and 20, and an instruction signal d of a predetermined arithmetic expression is input from the arithmetic instruction device 21.

Then, when the instruction signal d corresponding to the above equation (5) is input from the calculation instruction device 21, the median value D is calculated based on the distance information from the storage circuits 5 and 19, and the distance The signal is output to the display circuit 10, the lens drive control start circuit 13, and the comparison warning calculation circuit 11. As described above, at the same time as the start of the calculation, the gates 8 and 20 are closed via the shift register 9 to prevent information from being input to the calculation circuit 7 from the storage circuits 5 and 19.

When the output of the median value is input to the comparison warning calculation circuit 11, the shift register 9 advances and each stored information is input to the comparison warning calculation circuit 11. It is sequentially compared whether the depth of field is within the depth of field with respect to the median value determined by . At this time, an instruction signal d corresponding to an arithmetic expression for performing the comparison is inputted to the comparison warning arithmetic circuit 11 from the arithmetic instruction device 21.

In this case, when the depth of field is outside, an out signal is input to the distance display circuit 10 and the lens drive control start circuit 13 to display a warning and stop the operation of the photographic lens.

When the comparison with the distance information called by the shift register 9 is completed, a comparison completion signal e is inputted from the shift register 9 to the lens drive control start circuit 13. The lens drive control start circuit 13 receives the median output signal from the arithmetic circuit 7 and the comparison completion signal e, and when the out signal is not input from the comparison warning arithmetic circuit 11, the photographing lens operation is started, and the photographing lens is stopped based on the in-focus position, that is, a signal from the arithmetic circuit 7. Stopping of the photographic lens is detected by a lens drive control completion detection circuit 14, and a shutter drive control start circuit 15 is activated to control opening and closing of a shutter (not shown). Further, a detection signal is input from the lens drive control completion detection circuit 14 to the second memory cancel circuit 22, and the information in the memory circuit 19 is canceled by the output from the second memory cancel circuit 22, and the next shooting state is changed. Become.

However, if the stored information does not fall within the depth of field with respect to the median value, the photographing lens will not start operating, making it impossible to take photographs. In this case, the out signal cancel instruction circuit 23 and the absolute priority signal circuit 24 function.

That is, when the focus memory mechanism 16 is operated and the subject distance at which the user absolutely wants to focus is stored in, for example, the memory circuit 19, its contents are output to the memory display circuit 25 and displayed.
At this time, if the absolute priority signal is output from the absolute priority signal circuit 24 by human operation, the gate 2
6 stops working. In addition, out when outputting the out signal
The signal cancel instruction circuit 23 is also manually operated to maintain the operating state.

Now, the median value is calculated by the calculation circuit 7 based on the information in the storage circuits 5 and 19, and the comparison warning calculation circuit 11 compares whether the information in the storage circuits 5 and 19 is within the depth of field. It is done sequentially. In this case, when out signals are output for both the memory contents of the memory circuits 5 and 19, first, the information in the memory circuit 5 and the depth of field are compared and the output is output from the comparison warning calculation circuit 11. A signal is output, and the operation of the photographing lens is stopped by the lens drive control start circuit 13, and the signal is input to the third memory cancel circuit 27. On the other hand, the output from the comparison warning arithmetic circuit 11 activates the shift register 9, and a signal indicating that the comparison is being made with the stored contents of the memory circuit 5 is input to the third memory cancel circuit 27, and the gate 28 is activated. state and this gate 2
The memory contents of the memory circuit 5 are canceled by the cancel information outputted through the memory circuit 8.

Next, the comparison warning calculation circuit 11 is connected to the memory circuit 19.
The absolute priority signal circuit 24 is activated and the gate 26 is closed by the absolute priority signal, and the same cancel signal as in the case of the memory circuit 5 is output. is not output to the memory circuit 19.

Then, the shift register 9 advances sequentially, a completion signal from the shift register 9 is input to the out signal cancel instruction circuit 23, a signal instructing to calculate the median value is again input to the arithmetic circuit 7, The value calculation is performed again based on the stored information stored in the storage circuit 19. Here, since it is only the memory contents of the memory circuit 19, the memory information of the memory circuit 19 = median value,
It is possible to obtain a photograph in which only the desired subject selected by the user is in focus.

As described above, even if multiple subjects are not included in the depth of field, and shooting is interrupted and a warning is issued, one of the subjects can be given priority through manual operation, and the shooting can be continued. It has become possible to continue.

In the above configuration, when distance measurement is performed using only one focus memory mechanism 16, the distance measurement device 3 is activated by operating the focus memory mechanism 16 to output distance measurement information. Furthermore, since the shift register 17 is operating and the gate 18 is also operating, distance measurement information is input to the storage circuit 19. Information to operate only with stored information is artificially input from the focus memory mechanism 16 to the gate 2.
And gate 4 is inoperative.

If the release mechanism 1 is operated in this state, the operation signal is stopped at the gate 2 and the distance measuring device 3 is not activated. When the release mechanism 1 is further operated, the calculation start signal C is input to the calculation circuit 7, and the median value is calculated based on the information stored in the storage circuit 19. Here, if there is only one piece of memory information,
Storage information of this storage circuit 19 = median value,
The subsequent operation order is the same as that of the normal release mechanism 1, so a description thereof will be omitted.

In addition, when measuring distance using only a plurality of focus memory mechanisms 16, each focus memory mechanism 16
With this operation, the distance measuring device 3 is activated and outputs distance measurement information. At the same time, shift register 17 and gate 1
8 is also in the operating state, the distance measurement information is input to the storage circuit 19. Then, by sequentially operating the focus memory mechanism 16, the shift register 1
7 sequentially advances to sequentially operate each gate 29, 30, 31, and sequentially store distance measurement information in each storage circuit 33, 34, 35. It goes without saying that the release mechanism 1 prevents distance measurement information from being artificially output to the gates 2 and 4. Note that the calculation of the median value and the like are as described above, and furthermore, even when a plurality of focus memory mechanisms 16 and release mechanisms 1 are used together, it can be easily understood from the above explanation.

Furthermore, when an out signal indicating that the depth of field is outside is output from the comparison warning calculation circuit 11,
If the out signal cancel instruction circuit 23, which is manually operated in advance before shooting, is operated, the above-mentioned
The out signal cancels the stored information in each of the storage circuits 19, 33, 34, and 35 that is not within the depth of field. Then, when all the operations of the comparison warning calculation circuit 11 are completed, the shift register 9 outputs a comparison completion signal e, starts calculation again, and calculates the median value based on the remaining stored information. is again output from the calculation circuit 7, a comparison warning is issued by the comparison warning calculation circuit 11, and drive control of the photographing lens is started.

The arithmetic circuit 7 outputs a median signal, and the comparison warning arithmetic circuit 11 does not output an out signal.
When the comparison completion signal d indicating that all comparisons have been completed is input from the shift register 9 to the lens drive control start circuit 13, lens drive control is started and the photographing lens is brought to the in-focus position based on the median value signal. Here, the second memory cancel circuit 22 is activated by the detection signal from the lens drive control completion detection circuit 14, and all stored information is canceled and the shutter is driven to open and close. The configuration described above is included in the configuration shown in FIG. Note that the gate 2 is configured so that the distance measuring device 3 is not activated by the release mechanism 1 when a photograph is taken using only information from the focus memory mechanism 16. The second memory cancel circuit 22 also includes a manual cancel instruction button 3.
If 6 is added, it is convenient to cancel the stored contents when erroneous information is inadvertently stored. This manual cancel instruction button 36 can be simplified, for example, by having a configuration in which it also serves as an operating member for the battery check circuit.

Next, a case will be described in which focusing is performed in consideration of the exposure amount during strobe photography.

In this case, the above configuration is combined with a normal shooting/flash shooting selection device (hereinafter referred to as AE/Flash shooting selection device for simplicity).
FM selection device) 37, aperture value F No. calculation circuit 38, guide number G No. information device 39, exposure amount width setting device 40, strobe interlocking external regulation circuit 41, aperture value F No. information device 42, photometry device 43, gate 4
4, 45...49, memory circuits 50...54, average exposure value v calculation circuit 55, brightness display device 56, gates 57...59, and absolute priority signal circuits 60...62 are added.

In this configuration, first, the AE/FM selection device 37 is set to FM mode, and the AE/FM selection device 37 is set to the FM mode.
The FM mode signal from 7 is output to the calculation instruction device 21, guide number G No. information device 39, and shutter drive control start circuit 15, respectively. The calculation instruction device 21 outputs a signal corresponding to the above equation (16b) to the D calculation circuit 7.

In the arithmetic circuit 7, based on the above formula (16b),
Based on one or more pieces of distance information output from the plurality of memory circuits 5, 19, 33, 34, and 35, an exposure amount equivalent to 1/2 of the strobe exposure amount at the farthest distance and nearest distance to the subject is determined. Compute the median value to obtain. This calculated median value is calculated by the distance display circuit 10, the lens drive control start circuit 13,
It is added to the comparison warning calculation circuit 11 and the aperture value F No. calculation circuit 38.

The aperture value F No. calculation circuit 38 calculates a flash mechanical calculation formula (G No.= F×s), the aperture value FNo. at the median value is calculated and output to the distance width calculation circuit 12.

The distance width calculation circuit 12 calculates, for example, ± the exposure amount at the aperture value FNo.
The near side and far side distance ranges corresponding to the exposure width of 1v are calculated and outputted to the comparison warning calculation circuit 11. The exposure width can be arbitrarily set by the exposure width setting device 40 according to the allowable exposure range of the film used.

On the other hand, the comparison warning calculation circuit 11 compares the difference between each distance information from each storage circuit 5, 19, 33, 34, and 35 and the median value with the output information from the distance width calculation circuit 12, i.e. , a comparison is made to determine whether or not the distance is within a predetermined exposure amount width. If all of the differences are within the above distance range, the out signal is not output and the shift register 9
The lens drive control start circuit 1 receives the comparison completion signal from
4 is started, and thereafter, the photographing lens control operation and the shutter control operation are performed in the same manner as described above.

Note that at this time, the shutter drive control starting circuit 1
5 inputs the FM mode signal from the AE/FM selection device 37 and sets the shutter speed to synchronize with the strobe light emission operation.

Also, contrary to the above, any of the above differences,
If it is outside the above distance range, the comparison warning calculation circuit 11
The out distance display circuit 10 and the lens drive control start circuit 13 are outputted from the out distance display circuit 10 and the lens drive control start circuit 13, and together with the warning display, the lens control start operation is blocked. However, as mentioned above, the absolute priority signal circuit 2
4, when a specific subject is specified, distance information corresponding to that subject is left in any of the memory circuits 5, 19, 33, ... 35, so this distance information is the median value. The signal is then output to the lens drive control start circuit 13, and thereafter, a lens drive control operation and a shutter drive control operation are performed based on this median output signal.

Furthermore, the strobe interlocking external regulation circuit 41 uses the light emission amount and film sensitivity information output from the guide number G No. information device 39, and the aperture value F No.
The distance limit range of the strobe on the near and far side determined by the maximum F value (Fmax) and minimum F value (Fmin) of the photographing lens in use outputted from the information device 42 is determined by the allowable exposure amount from the exposure amount width setting device 40. Regulations should be made taking into account the width. This regulated strobe limit distance range information is input to the comparison warning calculation circuit 11,
The comparison warning calculation circuit 11 performs the comparison warning operation within the regulated strobe limit distance range.

Therefore, if any of the above stored information is out of the strobe limit distance range that takes into account the allowable exposure range, the out signal from the comparison warning calculation circuit 11 will be used to display the distance as described above. The signal is output to the device 10 and the lens drive control start circuit 13, a warning is displayed, and the lens drive control start operation is blocked.

Further, in connection with the operation of the focus memory mechanism 16, photometry is performed simultaneously with the above-mentioned distance measurement operation, and luminance information regarding the subject is transmitted to the gate 45.
The data is stored in the memory circuit 50 via the.

When the focus memory mechanism 16 is operated multiple times, distance measurement and photometry are performed each time, and the brightness information of multiple subjects is stored in each storage circuit by the shift register 17 via gates 45...49. 51, 52...54.

In this way, one or more pieces of brightness information stored in each of the storage circuits 50, 51, . be done. This calculation result is the AE/FM selection device 37 mentioned above.
Only when the AE mode is set, the shutter drive control start circuit 15 controls the shutter opening/closing operation based on the average exposure value v. This average exposure value v information is displayed on the brightness display device 56, and for example, this average exposure value v
If the shutter speed is slower than the predetermined shutter speed, an additional camera shake warning will be displayed.

Further, in the storage circuits 50...54, the cancel signal from the third memory cancel circuit 27 cancels the distance information in the storage circuits 5, 19, 33...35, and also cancels the distance information in the storage circuit 50 paired with this distance information. . . 54 is also canceled at the same time.

However, as mentioned above, the absolute priority signal circuit 2
When any of the gate circuits 26, 28, 57...59 specified by 4, 60...62 is closed, both memory circuits 5, 19, 33...35 and 5
0...54 are not canceled and can be photographed only for the prioritized subject.

As described above, since the structure is configured to perform photometry at the same time using the focus memory mechanism 16 and shift register 17 in conjunction with the focus memory mechanism 16, photometry for the main subject can also be performed. At the same time, it is also possible to store brightness information. Further, by photometry, the average exposure value v for the subject and the background can be calculated in the same manner as the operation by the focus memory mechanism 16 described above. By driving and controlling the opening and closing of the shutter using the average exposure value v, an unprecedented autofocus camera can be provided. Further, when an out signal is generated from the comparison warning calculation circuit 11, storage is canceled and the stored information is not input.

Effects of the Invention As detailed in the above embodiments, the present invention provides a camera used for flash photography, which includes a storage means for individually storing distance measurement values of at least two distance measurement points; Calculate a distance value at which the difference in exposure amount from flash photography is the same for the subject existing at the two distance measurement points stored in the means,
Next, a calculation means for calculating an aperture value at which a subject existing at this distance value will be properly exposed by flash photography from the film sensitivity and the amount of light emitted by the flash device, a release button, and a calculation means for calculating the aperture value at which a subject existing at this distance value will be properly exposed by flash photography; The apparatus is characterized by comprising a control means for controlling the aperture aperture to the control aperture value determined by the control aperture value calculation means, and is capable of storing distance measurement information of a plurality of objects having different photographing distances. , the predetermined positions between the subjects are calculated taking into account the allowable exposure range of the flash, and the aperture value is calculated and controlled based on this calculation result, so each of the multiple subjects can be properly exposed. It is possible to take photographs, and there is no inconvenience such as extremely inappropriate exposure of one of the subjects in the resulting photograph.

[Brief explanation of drawings]

Figure 1 is a graph showing the median depth of field.
FIG. 2 is a graph showing the median value of strobe exposure, and FIG. 3 is a block circuit diagram showing the structure of the present invention. 1... Release mechanism, 7... Arithmetic circuit, 5, 1
9, 33, 34, 35...memory circuit, 38...aperture value FNo. calculation circuit.

Claims (1)

[Scope of Claims] 1. In a camera used for flash photography, a storage means for individually storing distance measurement values of at least two distance measurement points, and two distance measurement points stored in the storage means. Calculate the distance value at which the difference in exposure amount from flash photography will be the same for the subject existing at this distance value, and then calculate the aperture value at which the subject existing at this distance value will be properly exposed by flash photography, as the film sensitivity. a control means for controlling the aperture aperture to a control aperture value determined by the control aperture value calculation means in response to the operation of the release button; A camera characterized by being equipped with. 2. The camera according to claim 1, wherein distance measurement is performed for each distance measurement point, and a distance measurement value is stored in the storage means for each distance measurement. 3. The storage means individually stores three or more distance measurement values, and the control aperture value calculation means selects two values, a maximum value and a minimum value, from among the plurality of distance measurement points stored in the storage means. 2. The camera according to claim 1, wherein the aperture value is calculated based on the distance measurement point.