JPS5927887B2 - Digital electric shutter with high and low brightness correction for single-lens reflex cameras - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a digital electric shutter with high and low brightness correction for a single-lens reflex camera that corrects both high brightness inappropriate exposure and low brightness inappropriate exposure.

In general, there are many high-brightness inappropriately exposed subjects everywhere, such as a snowy landscape reflected in the sun on a mountain in winter, or a coastline exposed to the midsummer sun.

When a photographer encounters such a subject, he or she often abandons photography due to instructions from the warning device. At a slightly more professional level, in such cases, a neutral filter (gray filter) is prepared separately, and an appropriate filter is attached to the camera depending on the proportion of high brightness. In other words, the brighter the light, the darker the filter that transmits less light. However, it is not only cumbersome to manually select the desired neutral filter based on the high brightness ratio and attach it to the lens each time, but it is also difficult to attach a filter when photographing a high-speed subject, such as a skier going downhill. Because you don't have time to do it, you end up missing out on valuable training. Furthermore, beginners such as the elderly and children tend to avoid photographing with a filter attached. Furthermore, in the case of a low-luminance inappropriately exposed subject, an auto strobe is attached to the camera to take the picture.

This auto-strobe is extremely convenient because the amount of light it emits is controlled in accordance with the distance at a constant aperture, and it provides an appropriate amount of light to the film, but it has the following drawbacks.

A. When firing a strobe, you have to manually adjust the shutter time to the X contact each time, which is cumbersome.
I often forget to adjust the settings and fail to take pictures. B
．． Although it is an electric shutter, the X contact (corresponding to a shutter time of 1/60 seconds) is operated mechanically, which is disadvantageous in terms of construction.

E. This is troublesome because it must be determined each time whether appropriate range photography is possible or whether strobe light should be emitted.

D. The aperture must also be set to a predetermined aperture value each time the strobe is fired, which is a problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide a digital electric shutter with high and low brightness correction for a single-lens reflex camera, which can automatically correct any inappropriate exposure exposure, whether high or low. Hereinafter, specific examples of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a specific example of a digital electric shutter with high and low brightness correction for a single-lens reflex camera according to the present invention. In the figure, reference numeral 1 denotes a photoresponse pulse generator that outputs a number of photoresponse pulses corresponding to the intensity of field light that has passed through the lens as a gate output of a gate circuit while a gate signal is applied. This photoresponsive pulse generator 1 includes a photoelectric element 2 that receives field light and outputs an electrical signal according to the incident light.
a first reference pulse generator 4 that generates a reference pulse, and a first reference pulse generator 4 that generates a reference pulse;
It is configured to include an AND circuit 5 as a gate circuit that controls passing of the reference pulse as a photoresponse pulse only during the time when the gate signal is being outputted. 6 is a fixed shutter time equivalent pulse generator that outputs a number of pulses corresponding to a predetermined shutter time (for example, 1/60 seconds); a second reference pulse generator 7 that generates a reference pulse; The gate signal of that time width is
A fixed shutter time setting timer 8 that outputs a signal ``1'' and outputs a signal ``O'' when the time elapses, and an AND circuit that serves as a gate circuit that allows the reference pulse to pass only for the time that the timer 8 outputs a signal ``1''. The circuit 9 is configured to include a circuit 9.

Reference numeral 10 designates an AND circuit as a gate circuit that allows a reference pulse from the second reference pulse generator 7 to pass when a shutter time restoration command signal "1" is output from a delay circuit 67, which will be described later. Reference numeral 11 designates a photoresponse pulse generator. The AND circuit 10 stores a light response pulse corresponding to the field light from the device 1.
This is a photoresponsive shutter time restoring device which restores the photoresponsive shutter time and outputs a first shutter closing signal when the reference pulse inputted through the reference pulse has a certain relationship with the stored value.

This photoresponse shutter time restoration device 11 includes a photoresponse pulse counter 12 that counts and stores photoresponse pulses, a reference pulse counter 13 that counts reference pulses given through an AND circuit 10, and a count value of this counter 13. and a first matching circuit 14 which outputs a first shutter close signal when the value matches the value stored in the photoresponse pulse counter 12. Each counter 12, 13 is 121 to 1
27, and 7 stages from 131 to 137. In this embodiment, the first stage 121 and the second stage 122 of the photoresponse pulse counter 12 are treated as high-intensity stages, and the third stage 122 is treated as a high-intensity stage.
The range from 23 to 5th level 125 is treated as the appropriate brightness level (・,
The sixth stage 126 and the seventh stage 127 are treated as low brightness stages. Reference numeral 15 stores a fixed shutter time equivalent pulse given from the fixed shutter time equivalent pulse generator 6, and when the reference pulse inputted through the AND circuit 10 has a certain relationship with the stored value, the fixed shutter time (for example, 1 /6
0 seconds) and outputs a second shutter close signal.

This device 15 includes a fixed shutter time equivalent pulse counter 16 that counts and stores fixed shutter time equivalent pulses;
A reference pulse counter 13 is also used as the photoresponsive shutter time restoration device 11, and a second shutter is provided which outputs a second shutter closing signal when the counted value of this counter 13 matches the stored value of a fixed shutter time equivalent pulse counter 16. 2 matching circuits 17. counter 16 is 16
It has a seven-stage configuration from 1 to 167. 18 determines the storage state of the high brightness stage, proper brightness stage, and low brightness stage of the photoresponse pulse counter 12, and outputs one of a high brightness signal, a proper brightness signal, and a low brightness signal according to the stored contents. and a gate circuit which inputs a gate signal from the photoresponsive pulse generator 1 and blocks the output of the signal from the abduction recircuit while the gate signal is present. and prohibited circuit 1
9. OR circuits 20 to 22, prohibition circuit 26 and OR circuit 2
7 constitutes the above-mentioned discrimination circuit, and prohibition circuit 2
3 to 25 constitute the gate circuits described above.

Reference numeral 28 denotes a filter selection circuit which selects a desired filter from among the plurality of high brightness correction filters 29 and 30 and attaches it to the front of the lens of the single-lens reflex camera.

This filter selection circuit 28 is usually arranged at a position where each filter 29, 30 is pulled against the tension force of each tension spring 31, 32 and removed from the front of the camera lens, and a locking claw is set at that position. 33, 34 and pivot hooks 35, 3
6, and when the electromagnetic magnets 37 and 38, which are disposed opposite to each other at the other ends of the pivot hooks 35 and 36, are energized, the opposing pivot hooks are rotated and engaged. The filter is disengaged from the retaining claw, and the filter is set in front of the camera lens by pulling the tension spring. Further, this filter selection circuit 28 has filter-mounted transistors 39 and 40 as switching means for controlling energization of the electromagnets 37 and 38 from a power source (not shown), and each transistor 39 and 40 is connected to an AND circuit 41 and 42. It is designed to be selectively conductive under the control of . The AND circuit 41 receives high-intensity signals from the prohibition circuit 19 and the prohibition circuit 26, and the AND circuit 42 receives high-intensity signals from the second stage 122 of the photoresponse pulse counter 12 and the prohibition circuit 26. Each of them is now working. Further, each filter 29, 30 is provided with a corresponding filter set signal generator 43, 44 which generates a filter set signal when the filter is set in front of the camera. Reference numeral 45 denotes a restart/reset signal generator that receives the filter set signal as input and generates a restart signal/reset signal, and includes a first monostable multivibrator 46, a differentiating circuit 49 comprising a capacitor 47 and a resistor 48, and It is configured with

A restart signal is outputted from the first monostable multivibrator 46 and given to the optical response timer 3, and a resetting signal is outputted from the differentiating circuit 49 and applied to the optical response pulse counter 1.
It is now being given to 2 people. Reference numeral 50 denotes an aperture drive circuit which uses the low luminance signal as an aperture Fbl leg input to set the aperture 51 to a predetermined value, and outputs an aperture correction end signal when the correction of the aperture 51 is completed.

52 is a first circuit which inputs a filter set signal, delays this signal by the re-photometry time, and outputs a first mirror flip-up signal; This mirror flip-up control circuit includes a second circuit that outputs a second mirror flip-up signal when a brightness signal exists or a low brightness signal and an aperture correction end signal exist.

The first circuit includes a second monostable multivibrator 55 that receives a filter set signal as an input and outputs a signal after delaying the photometry time when the signal is applied, and a second monostable multivibrator 55 that receives the output of this multivibrator 55 as an input. The third monostable multivibrator 56 outputs the first mirror flip-up signal when the signal is input.
The second circuit includes an OR circuit 79 that receives the appropriate brightness signal and the low brightness signal as input, an AND circuit 53 that receives the low brightness signal and the aperture correction end signal as input, and an AND circuit that takes the output of the OR circuit 79 as the normal input. 53 as an inhibit input. In addition, 57 is the first and second
This is an OR circuit that outputs a mirror flip-up signal to the mirror flip-up operation circuit 58. 58 is a mirror flip-up operation circuit that flips up a mirror (not shown) when each mirror flip-up control signal "1" is applied.

This circuit includes an electromagnetic magnet 59 for flipping up the mirror, a mirror flipping thyristor 60 for controlling the magnet, and resistors 61 and 62. Reference numeral 63 denotes a front curtain start operation that starts a front curtain (not shown) when a mirror flip-up operation signal [1] issued from a resistor 62 when the mirror flip-up operation circuit 58 operates is inputted via a delay circuit 67, which will be described later. It is a circuit.

This circuit includes an electromagnetic magnet 64 for starting the leading curtain, a leading curtain starting thyristor 65 for controlling the magnet, and a resistor 66. 67
has a capacitor 68, which delays the mirror flip-up operation signal by the mirror flip-up time and outputs the shutter time restoration command signal "1" and the leading curtain start command signal "1". It is a circuit.

69 is an auto strobe circuit which uses this as a trigger signal to cause the auto strobe tube 70 to emit light when the second shutter closing signal is applied, and 71 is an auto strobe circuit (not shown) which causes the auto strobe tube 70 to emit light when the first or second shutter closing signal is applied. This is a rear curtain start operation circuit that starts the curtain.

This circuit 71 includes an electromagnetic magnet 72 for starting the trailing curtain, a trailing curtain starting thyristor 73 for controlling the magnet, and a resistor 74.
75 is a first switching gate circuit which inputs the low brightness signal and the first shutter close signal and outputs the first shutter close signal when the low brightness signal is not present; The second shutter close signal switching output circuit is provided with a second switching gate circuit which receives the second shutter close signal as input and outputs the second shutter close signal when the low luminance signal is present.

This circuit 75 is composed of an inhibit circuit 76, an AND circuit 77, and an OR circuit 78. The inhibit circuit 76 functions as the first switching gate circuit described above, and the AND circuit 77 functions as the aforementioned second switching gate circuit. Acts as a gate circuit. Next, the operation of such an electric shutter is shown in Fig. 1 and Fig. 2 A-
1. This will be explained with reference to FIGS. 3A to 3F.

First, a case where field light is in a high brightness inappropriate exposure range will be described with reference to FIG. 1 and FIG. 2 A-1.

When the camera is aimed at the subject and a power supply (not shown) is closed in conjunction with the winding of the film, the photoresponse timer 3 starts operating due to the action of the photoelectric element 2 that receives the field light that has passed through the lens. As shown in Figure A, the gate signal “1”
Since the reference pulse from the first reference pulse generator 4 passes through the AND circuit 5 as a photoresponse pulse, the number of photoresponse pulse counters corresponds to the field light. 12, counted and stored. The completion of this storage is when the optical response timer 3 stops operating and issues a signal "0". On the other hand, the gate signal [1] from the photoresponse timer 3 is transmitted to the prohibition circuits 23 to 25.
The gates of these inhibit circuits 23 to 25 are all closed.

Therefore, the effect of successive changes in the stored value of the photoresponse pulse counter 12 does not appear on anything other than the photoresponse pulse counter 12. Under these circumstances, if storage is performed only in the first stage 121 of the photoresponse pulse counter 12, this is a high-brightness stage, and if you take a picture with this stage, you will end up with an overexposed and low-quality photograph. is obtained. Assuming that the time when storage is performed in the third stage 123 of the optical response pulse counter 12 is the fastest shutter time for that camera, this is 1/10.
If it is 00 seconds, the memory of the first stage described above corresponds to 1/4000 seconds. However, since the fastest shutter time is only 1/1000 seconds, mechanically it is not possible to shutter faster than this, resulting in scratches and overexposure. Therefore, in such cases, if you insert a well-known high-brightness correction filter made of a gray filter (also called a neutral filter) in front of the photographic lens, you can delay the shutter time and speed up the photographing process. It can be carried out.

The present invention attempts to do this automatically, and moreover, selects a high brightness correction filter that transmits different light depending on the intensity of high brightness. Now, when the storage in the first stage 121 of the photoresponse pulse counter 12 is completed, the gate signal from the photoresponse timer 3 changes from "1" to "O", so all the gates of the inhibition circuits 23 to 25 are be opened.

Therefore, the high brightness signal "1" stored in the first stage 121 is changed to the prohibition circuit 19 (the signal stored in the second stage 122 is "0").
”, the gate of this inhibition circuit 19 is open. ), it is divided into two parts, one directly goes to the gate of the AND circuit 41, and the other goes directly to the gate of the OR circuit 20 and the inhibition circuits 23, 26.
At this moment, the filter mounting transistor 39 is turned on, and as shown in FIG. Excitation is performed, the pivot hook 35 is rotated, the locking claw 33 is released, and the high brightness correction filter 29 is pulled by the tension spring 31 and is automatically installed in front of the camera lens. The transistor 39 turns off when the memory in the first stage 121 is [
0”. In this case, as mentioned above, the high-brightness shutter time corresponding to 1/4000 second is
/1000 seconds, the L value can be lowered in two steps.

In other words, if the filter 29 is designed in advance to reduce the L value by 2 steps, it will automatically reduce the L value by 2 steps to create a shutter time of 1/1000 seconds. I can do it. In addition, in this case, the prohibition circuit 26 controls the third stage 123 to the seventh stage 1 of the optical response pulse counter 12.
Since the stored values of each stage up to 27 are all "0", the gate is open.

The purpose of use of this prohibition circuit 26 is that when the memory extends to the proper and low brightness stages, the high brightness correction filter is installed by the signal from the first stage 121 or the second stage 122, making it impossible to take pictures. Therefore, this is to prevent automatic installation of these filters from occurring. Then, when the installation of the filter 29 is completed, at that moment the filter set signal generator 43 generates the filter set signal [1] as shown in FIG. 2C, and the first monostable multivibrator 4
Apply that signal to 6.

The first monostable multivibrator 46 receives this signal.
generates a signal "1" as shown in FIG. 2D. This signal "1" is differentiated by a differentiating circuit 49 and applied as a set signal to the photoresponse pulse counter 12 to clear the stored value. Do you obey? , the storage signal “1” of the first stage 121 is “
0], and as shown in Figure 2B, the filter installation signal "
1" becomes "O". Also, this signal "1" is applied to the optical response timer 3 as a restart signal to restart it, and as shown in FIG. "1" is output. Therefore, the reference pulse is sequentially sent to the photoresponse pulse counter 12 again. However, in this case, since the light attenuated by the high-intensity correction filter 29 is incident on the photoelectric element 2, the timer time becomes longer than before, and therefore the number of pulses sent also becomes larger than before. That is,
In this case, since the filter 29 is designed in advance to have a density of two stages based on the L value, the next storage of the photoresponse pulse counter 12 will be performed at the third stage 123, and the shutter time will be 1/ What used to be 4000 seconds becomes 1/1000 second.

Therefore, the appropriate luminance signal "1" stored in the third stage 123
is the OR circuit 21. Since the signal is applied to the inhibit input terminal of the inhibit circuit 26 via the inhibit circuit 24 and the OR circuit 27, the inhibit circuit 26 outputs the signal [0], which is applied to each AND circuit 41 and 42 of the filter selection circuit 28. Therefore, the gates of these AND circuits 41 and 42 are all closed. The reason why we provided this process of closing the gates of the AND circuits 41 and 42 is because in this case, by assumption, the signal "1" is stored only in the third stage 123 of the optical response pulse counter 12, and therefore 1st row 121 and 2nd row 1
22's memory is "O" so there is no problem,
If there is a signal "1" in the first stage 121 or the second stage 122, or both stages, this will turn on the transistors 39 and 40, and the filters 29 and 30 will be installed. In order to prevent this, a prohibition circuit 26 is provided to prevent this photographing when the light is suitable, and AND circuits 41 and 42 are provided.
The gate is closed.

On the other hand, the filter set signal [1] from the filter set signal generator 43 is applied to the first monostable multivibrator 4.
6, it is also applied to the second monostable multivibrator 55, and as shown in FIG. It comes to be output to the multivibrator 56. When the time required for remeasurement has elapsed, the output signal of the second monostable multivibrator 55 becomes "O", and at the fall of this signal, the third monostable multivibrator 56 switches to the second
It is activated as shown in FIG. This turns on the thyristor 60, excites the electromagnetic magnet 59, and flips up the mirror (not shown) at the timing shown in FIG. 2G. The capacitor 68 connected to the cathode side of the thyristor 60 delays the operation signal of the mirror flip-up operation circuit 58 by a delay time corresponding to the mirror flip-up operation time width shown in FIG. 2G. It is. The purpose of the delay using the capacitor 68 is to prevent the front curtain from starting while the mirror is flipping up. During the mirror flip-up operation when the resistor 62 is turned on due to conduction of the thyristor 60, the signal “1” is sent to the capacitor 68 of the delay circuit 67.
When the delay is applied to the thyristor 65 of the front curtain start operation circuit 63, the thyristor 65 is turned on, the electromagnetic magnet 64 is excited, and the start of the front curtain (not shown) is automatically started as shown in FIG. 2H. It will be done at the right time.

Further, the mirror flip-up operation signal is delayed by a delay circuit 67 and then applied to the AND circuit 10 as a shutter time restoration command signal "1". As a result, the reference pulse from the second reference pulse generator 7 is transferred to the reference pulse counter 13.
will be sent to. When the count value of the reference pulse counter 13 and the stored value of the photoresponse pulse counter 12 match, the photoresponse shutter time is restored, and the first shutter closing signal "1" is output from the first matching circuit 14, applied to the inhibit circuit 76. At this time, the low luminance stage of the light response pulse counter 12 is in the state of the signal "0", so the inhibition circuit 76 to which this signal "O" is applied passes the first shutter closing signal "1", and the OR circuit The signal is applied to the thyristor 73 of the trailing curtain start operation circuit 71 via 78. This turns on the thyristor 73 as shown in FIG. 2,
The electromagnetic magnet 72 is excited, and the rear curtain (not shown) is started. The trailing curtain is started as described above, but if the gate of the AND circuit 77 is not closed at this time, the contents of the optical response pulse counter 12 and the reference pulse counter 13 will become equal and the trailing curtain will not start. After this, the contents of the fixed shutter time equivalent pulse counter 16 of the fixed shutter time restoring device 15 and the reference pulse counter 13 become equal, and a second shutter close signal is output from the second match circuit 17 to output the auto strobe circuit. 69 is activated, causing the strobe tube 70 to emit light.

To prevent this, an AND circuit 77 is used.
Note that when the field light is in the high brightness range, the memory signal of the low brightness stage of the light response pulse counter 12 is "O" as described above, so the aperture drive circuit 50 does not operate, and therefore the aperture 51 is not automatically corrected, and the initial preset state is maintained.The above was a case of field light corresponding to 1/4000 seconds, but next, the case of field light corresponding to 1/2000 seconds Let's discuss the case.

In this case, the second stage 12 of the optical response pulse counter 12
A signal "1" is stored in the second stage, and "0" is stored in the first stage 12 and the third stage 123 to the seventh stage 127. Therefore, at this time, unlike the above, the high brightness signal "1" is applied to the filter mounted transistor 40 via the AND circuit 42, so the electromagnetic magnet 38 corrects the high brightness by 1L brighter than before. filter 30 will be selected and mounted in front of the camera lens. The installation process is the same as described above, and the subsequent shutter time restoration process is also performed in the same manner as described above. In addition,
The reason why the prohibition circuit 19 is connected is that if the stored value is the first stage 121 and 2 of the optical response pulse counter 12,
If the transistors 39 and 40 with filters are simultaneously operated in the stage 122, the filters 2 and 2 are simultaneously operated.
This is to prevent 9 and 30 from being attached at the same time. That is, if the signal "1" is stored in both the first stage 121 and the second stage 122, the filter selection circuit 28 is controlled by the signal "1" in the second stage 122. In this embodiment, for convenience of explanation, the prohibition circuit 19 is inserted to compensate for the high luminance correction for each LV, but if it is desired to insert the filter more precisely (1.
In the sense that you want to compensate even in the case of high brightness such as 5LV, in such a case, the first stage 121 and the second stage 122
This is a case where the signal "1" is stored at the same time.

), a known decoder may be used. In this embodiment, the used filter is returned to its original position by means not shown in conjunction with the winding of the film.

Next, a case where field light is in the appropriate exposure range will be described.

In this case, the stored signal "1" is detected by the optical response pulse counter 1.
This is the case where the data exists from the third stage 123 to the fifth stage 125 of 2.

In such a case, since the output signal of the OR circuit 21 is "1", the gate of the prohibition circuit 26 always remains closed, so even if the signal "
1], the gates of the AND circuits 41 and 42 are closed, and selective mounting of the filter is never performed. Further, the output signal [1] of the OR circuit 21 is transmitted to the prohibition circuit 24,
It is input to the prohibition circuit 54 via the OR circuit 79 as normal human input. At this time, the OR circuit 53 outputs "0" from the prohibition circuit 25 and "0" from the aperture drive circuit 50, so
AND output is "0". Therefore, the prohibition circuit 54 which uses this AND output as a prohibition input outputs the second mirror flip-up signal "1" at this time, and this signal is applied to the mirror flip-up operation circuit 58, causing the mirror to be flipped up. I,
As described above, the shutter is then automatically opened and closed. In this case, of course, the optical response timer 3 operates only once.

In other words, no correction is required. Next, a case where field light is in a low luminance inappropriate exposure range will be described with reference to FIGS. 1 and 3A to 3F.

In this case, the photoresponse timer 3 outputs the gate signal “1” to the third
This signal "1" opens the gate of the AND circuit 5 and applies the reference pulse to the photoresponse pulse counter 12, and the stored signal "1" is applied to the six stages of the photoresponse pulse counter 12. This is when the number reaches from the 126th row to the 7th row 127.

In this way, when the stored signal "1" reaches the low luminance stage, the signal "1" necessarily passes through the first stage 121 to the fifth stage 125 or is stored in these stages. There is. However, this signal "1" should not cause the filter to be installed or the shutter to open or close immediately as it is within the appropriate range.

That is, in this case, proper exposure can only be obtained by firing the auto strobe. From this point of view, it is an extremely difficult problem in terms of invention to make a circuit work with a certain signal only when necessary, and prevent the circuit from working when it is unnecessary, even though the same signal is present. This can also be said to be the essence of the invention.

It is considered that the invention deserves special mention for overcoming such technical difficulties, which was one of the difficulties encountered in the invention. Now, as described above, the photoresponse pulse counter 1
When the signal "1" reaches either or both of the sixth stage 126 or the seventh stage 127 of the second stage, this signal [1] is sent to the prohibition circuit 26 via the OR circuit 22, the prohibition circuit 25, and the OR circuit 27. Since it is applied to the inhibit input terminal and closes the gate, there is no influence from the stored values in the first stage 121 and second stage 122.

In other words, no filter is attached at all. 3rd row 12
The influence of the stored values in the third to fifth stages 125, that is, the drive of the mirror flip-up operation circuit 58 is not performed because the gate of the prohibition circuit 54 is closed.

Therefore, we will discuss in detail how the gate of the inhibiting circuit 54 is closed and how the aperture is driven. The low brightness signal "1" from the low brightness stage of the photoresponse pulse counter 12 closes the gate of the inhibit circuit 76 and opens the gate of the AND circuit 77 to prepare for strobe light emission.

On the other hand, since this low brightness signal "1" is also applied to the aperture drive circuit 50, the aperture 51 is rotationally driven from the initially set aperture value to a predetermined aperture value.

One driving period of this aperture 51 is shown in FIG. 3B. The reason why the aperture 51 is driven to a predetermined aperture value in this manner will be explained below.

Normally, with an auto strobe, once the aperture 51 is fixed at a certain aperture value, the amount of light emitted is controlled according to the distance, so that the negative is always exposed to the appropriate amount. This predetermined aperture value is specified by each manufacturer, and is usually around F4 to F5 or F6. When the aperture 51 is opened, it becomes possible to control light emission to a distant place with the same guide number, but since the depth of field becomes shallow, there is a risk that the image will be out of focus in wide-open shooting. On the other hand, in order to avoid out-of-focus, it is better to close down the aperture 51 deeply, but stopping down causes a loss of light, and F4 to F5, 6
It becomes impossible to control light emission at a distance compared to the case of .
For this reason, if a predetermined aperture value is determined in advance, ideal strobe photography can be performed. For example, F5.
If 6 is preferable, the initially set aperture should be Fl. 4 or Fll, it will automatically be set to F5 for flash photography.
All you have to do is switch to 6.

As will be described later, the aperture drive circuit 50 outputs a signal [1] if the initially set aperture value is different from the predetermined aperture value, and outputs a signal [0] if they are the same, and applies this to the AND circuit 53. .

Therefore, when automatic correction of the diaphragm 51 is performed, the diaphragm drive circuit 50 outputs the diaphragm correction end signal [0] to the AND circuit 53, so the AND circuit 53 outputs the signal ``0'' to the prohibition input terminal of the prohibition circuit 54. to be applied.

At this time, the prohibition circuit 25 is connected to the normal input terminal of the prohibition circuit 54.
A low brightness signal "1" is applied from the OR circuit 79. Therefore, when the prohibition circuit 54 completes the automatic correction of the aperture 51, the prohibition circuit 54 sends the first mirror flip-up signal "1" to the OR circuit 5.
7 to the mirror flip-up operation circuit 58, and the mirror is flipped up at the timing shown in FIG. 3C. Then, after the required time to flip up the mirror, the front curtain start operation circuit 63
is activated, and the leading curtain is started at the timing shown in FIG. When the counted value of the reference pulse counter 13 and the fixed shutter time equivalent pulse counter 16 match, the second shutter close signal is outputted from the second matching circuit 17, and is sent to the auto strobe circuit 69 via the AND circuit 77 and then to the AND circuit 77. In addition to the circuit 77, the trailing curtain start operation circuit 71 is connected via an OR circuit 78.
is applied to. Therefore, at this time, the rear curtain start operation circuit 71
is activated, and the rear curtain is launched at the timing shown in Figure 3E.
Then, the auto strobe tube 70 emits light at the timing shown in FIG. 3F, and photographing is completed. Since the shutter time at this time is 1/60 seconds, in order to restore such a shutter time, the constant stored value of the fixed shutter time equivalent pulse counter 16 is set in advance to the reference pulse generator 7 and the fixed shutter time. It is selected based on the correlation with the setting timer 8.

The reason why I chose 1/60 second is that for cameras such as single-lens reflex cameras, where the shutter time is generally determined by the start of the front and rear curtains, the shutter opens fully from exactly 1/60 second. It is from. 1/60 second is generally said to be the limit for camera shake, and 1/30 second slower than this is said to cause some risk of camera shake, so 1/60 second is selected. FIG. 4A shows a filter (representatively filter 29).

Other filters have similar configurations. ) 29 is shown before it is attached to the lens 81 of the camera 80, and FIG. ) has a similar configuration.) The specific configuration of 43 is shown below. Note that 82 is a holding plate for the filter 29. The filter set signal generator 43 has a movable contact 43A provided on the filter holding plate 82, and a signal that is short-circuited by the movable contact 43A when the filter 29 is mounted in front of the lens 81.
It is configured to include a pair of fixed contacts 43B and 43C.

FIG. 5 shows a specific circuit example of the optical response timer 3 mentioned above.

This photoresponse timer 3 is connected in series with the short-circuiting transistor 83 driven by the restart signal "1" from the first monostable multivibrator 46 and the aforementioned photoelectric element 2, and is connected between the collector and emitter of the short-circuiting transistor 83. a switching transistor 85 whose base is connected to the connection point between the photoelectric element 2 and the time-limiting capacitor 48;
The resistor 86 is connected in series to the collector of the resistor 86. In such a photoresponse timer 3, when a power switch (not shown) is closed in conjunction with, for example, film winding, charging of the time constant capacitor 84 via the photoelectric element 2 is started.

At this time, the first monostable multipipulator 46 is in a stationary state because it is not receiving the filter set signal "1".
Since the signal "0" is output, the shorting transistor 83 of the time constant capacitor 84 is in an off state. Therefore, the gate signal [1] is applied from the collector of the switching transistor 85 to the AND circuit 5 and the inhibition circuits 23 to 25 in FIG. A photoresponse pulse is sent to the photoresponse pulse counter 12 during the application period of this gate signal "1". When the terminal voltage of the time constant capacitor 84 reaches a predetermined level voltage, the switching transistor 85 is turned on and the output signal changes from "1" to "0".
”. At this time, the storage of the optical response pulse counter 12 is completed. This is the first operation of the photoresponse timer 3.

Next, when the filter set signal [1] is applied from the filter set signal generators 43 and 44 to the first monostable multivibrator 46, a restart signal "1" is outputted at this moment and applied to the shorting transistor 83. do. As a result, this transistor 83 is turned on, and the time-limiting capacitor 84 discharges its internal charge. Then, after a certain period of time, the first
The monostable multivibrator 46 returns to its initial state,
Since the signal changes from "1" to "0", the shorting transistor 83 is turned off again, and charging of the time-limiting capacitor 84 via the photoelectric element 2 is restarted. Then, the second re-memory, that is, after the filter is attached, is completed.

The first monostable multivibrator 46 may be of any known type, including a configuration of individual transistors, a linear IC,
Any configuration of digital IC may be used, but the time it takes for the signal "1" to be output in response to the filter set signal and for it to return to "0" or its pulse width is determined by the optical response pulse counter 12.
After being cleared, the time constant capacitor 84 passes through the photoelectric element 2.
All you have to do is select it so that the second charging of the battery starts. This pulse width can be selected, as is well known, by appropriately selecting the elements that determine the time constant within the monostable multipiperator. Figure 6 shows the aperture and drive circuit 50.
This figure shows an example of a specific configuration.

In the figure, 87 is a variable resistor, and a fixed sliding resistor 8
7A and a slider 87B that slides in contact with the slider 87B, and the slider 87B is driven in conjunction with the movement of the aperture 51. 88 is an aperture drive motor that drives the aperture 51, 89 is a transistor 89A, 8
9B and a differential amplifier consisting of resistors 89C to 89E, 90
A and 90B are variable resistors and fixed resistors that constitute the voltage dividing circuit 90.

The differential amplifier 89 receives one input voltage 1 from the slider 87B.
is applied, and the other input voltage V2 is applied from the voltage dividing point of the voltage dividing circuit 90. 91 is an amplifier that amplifies the unbalanced signal from the differential amplifier 89 and supplies it to the motor 88 via electric lines 92A and 92B; 93 and 94 are electric lines 9
A light emitting visual object such as a lamp or a light emitting diode is connected between 2A and 92B.

95 is a relay switch 95 connected to the electric circuit 92A.
A and a relay magnet 95B that drives the relay, 96 is a transistor that is turned on by the signal "1" from the inhibit circuit 25 to excite the relay magnet 95B, and these 95 and 96 act as a loop opening/closing means. 97.

This loop opening/closing means 97 includes a closed loop prohibition circuit 2 which includes an aperture drive motor 88, an aperture 51, a variable resistor 87, a differential amplifier 89, a voltage dividing circuit 90, and an amplifier 91.
This is for opening and closing with the signal from 5. 98,99
100 is a resistor, 100 is a photoelectric element, and 101 is a Schmitt circuit.

The photoelectric element 100 forms a voltage dividing circuit with the resistor 98, and a signal from the voltage dividing point is applied to the Schmitt circuit 101. The photoelectric element 100 is optically coupled to a light-emitting viewer 93, and these elements 93, 98, and 100 form a Schmitt drive signal generating circuit 102. 10 more
2, 99, and 101, aperture correction signal generation circuit 103
is formed. Next, the operation of such aperture drive circuit 50 will be explained.

If the aperture 51 is arbitrarily selected in advance before shooting, the aperture 5
Assume that the slider 87B added to 1 is located at the illustrated position of the fixed sliding resistor 87A. The divided voltage V1 obtained from this slider 87B is the transistor 8 of the differential amplifier 89.
It is input to 9A. The divided voltage V2 from the voltage dividing circuit 90 is input to the other transistor 89B. Under the above circumstances, when the low luminance signal "1" from the first photoresponse pulse counter 12 is input to the aperture drive circuit 50 via the OR circuit 22 and the inhibition circuit 25, the transistor Shio 9
6 is turned on, relay magnet 95B is energized,
Relay switch 95A is turned on. Therefore, the slider 8
7B at the illustrated position, if V1>V2 (assuming that such a state is a high F value and assuming Fll), the output of the differential amplifier 89 is sent to the amplifier 9 as an unbalanced signal.
1, the motor 88 starts rotating due to the amplified unbalanced signal.

This rotation drives the diaphragm 51 by 1 in the direction to open it (in the direction of the ground line in the figure), so V1 gradually decreases, and when it reaches V1-V2, the unbalanced signal becomes "O" and the motor 88 is activated. The rotation is stopped and the aperture value settles to a predetermined value.

This aperture value is about F4 to F5.6 as mentioned above. The reason why the light emitting visual recognition body 93 is connected to the output end of the amplifier 91 is to display to the photographer that the initially set aperture value has been canceled and a predetermined aperture value has been obtained. In this case, the light-emitting visual body 93 lights up with an unbalanced signal, and this lighting causes the aperture 5
The light continues during the first rotation, and is turned off when a predetermined aperture value is reached. When the light-emitting visual recognition body 93 lights up, the photoelectric element 100 (for example, CdS, etc.) of the Schmitt drive signal generation circuit 102 that receives the irradiated light has a low internal resistance, so the Schmitt circuit 101 does not reverse, that is, remains stationary. Since the output signal "1" is being generated (the output from the previous stage of the Schmitt circuit 101 is being taken out).

), the AND circuit 53 outputs a signal "1", and the prohibition circuit 5
Gate 4 is closed. In other words, if the initially set aperture value differs from the predetermined aperture value, the light-emitting visual recognition body 93 is always turned on by the unbalanced signal, so that the signal "1" is generated and the gate of the prohibition circuit 54 is closed. Next, the rotation of the diaphragm 51 leads to V1-V2, and the light emitting visual recognition body 93
When the light goes out, the Schmitts circuit 101 inverts and outputs the aperture correction end signal "O", so the output from the AND circuit 53 is "O", and therefore the gate of the prohibition circuit 54 is opened and the low brightness signal becomes the first is output as a mirror flip-up signal [1], the mirror flip-up operation circuit 58 is driven, and the mirror is flipped up.

Note that when the field light is appropriate, the Schmitt circuit 101 outputs "O" because the loop opening/closing means 97 is opened and the light emitting visual recognition body 93 does not light up.

On the other hand, if the initially set aperture value is on the open side (if it is on the F2 position), contrary to the above, then the slider 87B
Since it is on the ground line side from the beginning, it is in the state of V1 and V2.

Therefore, in this case as well, the motor 88 will be rotated because the unbalanced signal is input to the amplifier 91, but since this unbalanced signal has the opposite polarity than before, the rotation of the motor 88 will also be reversed. Become. Therefore, since the aperture 51 also rotates in the opposite direction to that described above, the slider 87B is slid toward the hot line side (+E side), and the motor 88 is moved in the same manner as described above in that V1-V2 is reached.
rotation will be stopped. Therefore, in the case of the aperture 1 drive circuit 50 shown in FIG. 6, even if the photographer sets an arbitrary aperture value that he/she desires before taking a picture, the F value may be high in the low luminance region. Since the predetermined aperture value can always be reached, extremely advantageous strobe photography can be performed.

Note that if the light emitting visual recognition body 94 is connected to the input end of the motor 88, the following advantages will arise.

This is because the appropriate/improper brightness range can be determined by turning on and off the light-emitting visual recognition body 94. That is, in this case, the light emitting visual recognition body 94 is turned on only when the brightness is in the low brightness range when the relay switch 95A is closed, and remains off when the brightness is in the appropriate brightness range. Further, the variable resistor 90A is used when it is necessary to change a predetermined aperture value.

As explained above, in the diaphragm drive circuit 50 shown in FIG. 6, the turning on and off of the light emitting visual recognition body 93 is used to drive the Schmitt circuit 101, but the present invention is not necessarily limited to this. , for example, may be performed purely electronically as shown in FIG. FIG. 7 shows an example in which a well-known absolute value circuit is used as the Schmitt drive signal generation circuit 102.

In such a case, as is well known, the output from the absolute value circuit always generates a voltage of the same polarity (in this case, positive voltage) regardless of whether the input is positive or negative, so this voltage can be applied to the Schmitt circuit 101. In this case, since we are targeting a Schmitt circuit, we used a combination of a light-emitting visual object and a photoelectric element, or an absolute value circuit, but if we use a comparator using a well-known operational amplifier, a circuit configuration other than the one shown can be used. Conceivable. The electric shutter of the present invention is not limited to the embodiment shown in the drawings, but may have the following configuration, for example.

In the above embodiment, one filter is required for each increase in the number of high-brightness stages. If it is designed in a logical manner, it can be used logically such that combining stages 1 and 2 will result in 3 stages of dimming, and combining stages 1 and 4 will result in 5 stages of dimming. can.

With such a configuration, the number of filters used can be reduced. Each filter device may be in the form of a floodlight filter for use in stage lighting, for example.

The shutter time restoring devices 11 and 15 are not limited to the matching type shown, but may also be of the well-known addition/subtraction type, inversion type, or the like. Fixed shutter time restoration device 15
may be independently provided with a reference pulse counter.

The loop opening/closing means 97 is not limited to the illustrated position, but may be provided at any position of the closed loop described above.

In this case, between the motor 88 and the diaphragm 51 or between the diaphragm 51
When provided between the loop opening and closing means 97 and the variable resistor 87, the loop opening and closing means 97 becomes a mechanical opening and closing means.

As explained above, the digital electric shutter with high and low brightness correction for single-lens reflex cameras according to the present invention automatically corrects high and low brightness by simply pointing the camera at the subject and closing the power switch. Since the camera is photographed automatically, you can greatly expand your photographic options.

Further, in the present invention, since the shutter release is performed automatically, it is possible to take pictures with almost no camera shake. Therefore, it is possible to provide a single-lens reflex camera that is easy to handle not only for professionals but also for beginners, the elderly, and children. Furthermore, since the present invention has a structure in which the fixed shutter time is restored by a fixed shutter time restoration device made of an electric circuit, both the shutter closing signal and the photoresponsive shutter time restoration device made of an electric circuit can be obtained as an electric signal. Therefore, selection control to be applied to the trailing curtain start operation circuit and the auto strobe circuit can be easily carried out. Further, the present invention includes a photoresponse pulse counter output control circuit,
While the photoresponse pulse generator is outputting the gate signal, the output signals from the high brightness stage, proper brightness stage, and low brightness stage of the photoresponse pulse counter are blocked from passing through. The effect of successive changes in stored values does not appear on anything other than the optical response pulse counter, and malfunctions can be prevented. Furthermore, in the present invention, when storage is performed only in the high-brightness stage of the photo-responsive pulse counter, the light-responsive pulse counter output control circuit provides the filter selection circuit with a high-brightness signal corresponding to the stored content. The camera automatically selects the required high-brightness correction filter, attaches it in front of the photographic lens, and performs photometry again, so high-brightness correction can be automatically performed using the high-brightness correction filter. .

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the electric shutter according to the present invention, and FIGS. 2A-1 and 3A-F are diagrams for explaining the operation timing of the electric shutter shown in FIG. 4A and 4B are perspective views showing an example of the state of the filter attachment mechanism used in FIG. 1 before and after the filter attachment mechanism is attached to the lens, and FIG. 5 is a perspective view of the filter attachment mechanism used in FIG. 6 is a circuit diagram showing an example of the aperture drive circuit used in Fig. 1. Fig. 7 is a circuit diagram showing an example of the aperture drive circuit used in Fig. 6. FIG. 7 is a block diagram showing a modification of the correction signal generation circuit. 1...Photoresponsive pulse generator, 2...Photoelectric element, 5...Gate circuit, 6...Fixed shutter time equivalent pulse generator, 4, 7...
Reference pulse generator, 11...Photoresponsive shutter time restoration device, 12...Photoresponse pulse counter,
13...Reference pulse counter, 14...
- First matching circuit, 15...Fixed shutter time restoration device, 16... Fixed shutter time equivalent pulse counter, 17... Second matching circuit, 18.
...Photoresponse pulse counter output control circuit, 26.
...Prohibition circuit, 28 ... Filter selection circuit, 29, 30 ... High brightness correction filter, 4
3, 44...Filter set signal generator, 50
...Aperture drive circuit, 51...Aperture, 5
2...Mirror flip-up control circuit, 54...
...Prohibited circuit, 57...OR circuit, 58...
...mirror flip-up operation circuit, 63.. ...Front curtain start operation circuit, 69...Auto strobe circuit,
70... Auto strobe tube, 71...
Rear curtain start operation circuit, 75... Shutter close signal switching output circuit, 79... OR circuit, 80...
... Single-lens reflex camera, 81 ... Lens, 87 ... Variable resistor, 88 ... Aperture drive motor, 89 ... Differential amplifier, 90...
...Voltage divider circuit, 91...Amplifier, 97...
. . . Loop opening/closing means, 103 . . . Signal generation circuit during aperture correction.

Claims (1)

[Scope of Claims] 1. A photoresponse pulse generator that outputs a number of photoresponse pulses as a gate output of a gate circuit while a gate signal is applied, the number of which corresponds to the intensity of field light that has passed through a lens; The photoresponsive pulse generator includes a fixed shutter time equivalent pulse generator that outputs a number of pulses corresponding to a predetermined shutter time, and a photoresponsive pulse counter that is divided into a high brightness stage, a proper brightness stage, and a low brightness stage. A number of photoresponse pulses corresponding to the field light given from the camera are stored in the photoresponse pulse counter, and the number of reference pulses applied by the shutter release is in a constant relationship with the value stored in the photoresponse pulse counter. a light-responsive shutter time restoring device that completes the restoration of the light-responsive shutter time and outputs a first shutter closing signal when the light-responsive shutter time reaches the end of the light, and a fixed shutter time equivalent pulse counter that outputs a first shutter closing signal; Fixed shutter time when shutter time equivalent pulses are stored in the fixed shutter time equivalent pulse counter and the number of reference pulses applied by shutter release has a constant relationship with the stored value of the fixed shutter time equivalent pulse counter. a fixed shutter time restoring device that completes the restoration and outputs a second shutter closing signal; and a fixed shutter time restoring device that determines the storage states of the high brightness stage, proper brightness stage, and low brightness stage of the photoresponse pulse counter and stores the stored contents. According to high brightness signal, suitable brightness signal,
A light-responsive pulse counter output control comprising a discrimination circuit that outputs any one of low luminance signals, and a gate circuit that receives the gate signal and blocks the output of the signal from the discrimination circuit while the gate signal is present. A predetermined filter is selected from a plurality of high-brightness correction filters under the control of the circuit and the high-brightness signal, and is mounted in front of the photographing lens, and a filter set signal is generated when the filter is mounted, and a filter set signal is generated. a filter selection circuit that provides a restart signal to the photoresponse pulse generator and a reset signal to the photoresponse pulse counter; and a filter selection circuit that uses the low luminance signal as an aperture control input to set an aperture to a predetermined value and correct the aperture. an aperture drive circuit that outputs an aperture correction end signal when the aperture correction is completed; a first circuit that receives the filter set signal and delays this signal by a re-photometry time to output a first mirror flip-up signal; and the appropriate brightness signal. and a second mirror flip-up signal that receives the low brightness signal and the aperture correction end signal as input and outputs a second mirror flip-up signal when the appropriate brightness signal exists or when the low brightness signal and the aperture correction end signal exist. a mirror flip-up control circuit comprising a mirror flip-up control circuit; a mirror flip-up operation circuit that causes the mirror to flip up using each of the mirror flip-up signals and outputs a mirror flip-up operation signal when the mirror flips up; A mirror flip-up time delay circuit that delays and outputs a mirror flip-up operation signal by the time required for mirror flip-up, and a front curtain start operation circuit that is driven by the delayed mirror flip-up operation signal to start the front curtain. a gate means that controls to start applying a reference pulse to the photoresponsive shutter time restoring device and the fixed shutter time restoring device under the control of the delayed mirror flip-up operation signal; a first switching gate circuit that receives a first shutter close signal as an input and outputs the first shutter close signal when the low brightness signal is not present; and a first switching gate circuit that receives the low brightness signal and the second shutter close signal. a shutter closing signal switching output circuit comprising a second switching gate circuit which receives as input and outputs the second shutter closing signal when the low luminance signal is present; an auto strobe circuit that causes strobe light to be emitted by using this as a trigger signal when the second shutter closing signal is given; and the first or second shutter closing signal is given from the first or second gate circuit. 1. A digital electric shutter with high and low brightness correction for a single-lens reflex camera, characterized in that it is equipped with a rear curtain start operation circuit that starts the rear curtain when the rear curtain is turned on. 2 The aperture drive circuit includes a variable resistor that generates a variable voltage V_1 in conjunction with the movement of the aperture and a slider, and a predetermined voltage V_1.
a voltage divider circuit that generates the voltage V_2; a differential amplifier that receives the voltages V_1 and V_2 and outputs an unbalanced signal until both voltages are balanced; and an amplifier that amplifies the unbalanced signal;
an aperture drive motor that drives the aperture in the opening or closing direction depending on the polarity of the unbalanced signal output from the amplifier and stops driving when the unbalanced signal disappears; A variable resistor, the differential amplifier, the voltage divider circuit, and the amplifier are provided at any position in a closed loop formed by the low brightness signal, and when the low brightness signal is present, the loop is closed to close the low brightness signal. a loop opening/closing means which opens the loop when the signal is absent; and a loop opening/closing means which receives the output signal of the amplifier as input and sends an aperture correction end signal to the mirror flip-up control circuit when the output signal is absent.
The single-lens reflex camera according to claim 1, further comprising an aperture correction signal generation circuit that outputs a signal "0" and outputs a signal "1" when the output signal exists. Digital electric shutter with high and low brightness correction for cameras. 3. The photoresponse pulse counter output control circuit is an inhibition circuit that inputs the proper luminance signal and the low luminance signal to an inhibition input terminal, controls passage of the high luminance signal, and applies the passage signal to the filter selection circuit. 26. A digital electric shutter with high and low brightness correction for a single-lens reflex camera according to claim 1 or 2 having the following claim. 4. The first circuit of the mirror flip-up control circuit:
A monostable multivibrator 55 which receives the filter set signal as an input and outputs a signal after delaying it by the re-photometry time when the signal is applied, and the signal is input with the output of the monostable multivibrator 55 as an input. The second circuit includes an OR circuit 79 which receives the appropriate brightness signal and the low brightness signal.
, an AND circuit 53 which receives the low luminance signal and the aperture correction end signal as inputs, and a prohibition circuit 54 which takes the output of the OR circuit 79 as a normal input and the output of the AND circuit 53 as a prohibition input. A digital electric shutter with high and low brightness correction for a single-lens reflex camera according to any one of claims 1 to 3.