JPS6020725B2 - Shutter time priority automatic exposure device that can expand the appropriate exposure range - Google Patents

Description

Detailed Description of the Invention This invention obtains aperture value information as a digital signal from subject brightness information, set shutter time information, etc., and automatically controls the camera's aperture according to this signal, so-called shutter time priority automatic exposure. Regarding equipment.

In this conventional type motion exposure device, all signals are processed in an analog manner.

Therefore, the accuracy was not very good, and since the aperture value was displayed using the meter pointer, it was difficult to read it clearly. Furthermore, in internal light-receiving type cameras, memory is carried out by clamping the meter pointer with a well-known comb-shaped member, which poses problems such as the meter pointer being easily damaged.

This invention is intended to eliminate the above-mentioned drawbacks by storing aperture value information digitally, and uses pulses corresponding to the aperture value calculated based on the brightness of the subject and a preset shutter time. a digital storage device for storing the pulses, comprising a pulse oscillator for generating the pulses, storage stages for underexposure, proper area, and overexposure, and each input terminal for increasing and decreasing the storage amount; an aperture drive circuit that controls the aperture according to the value stored in the storage device; a display device that displays the stored value; a shirt evening time setting member that generates one shirt time correction pulse per unit rotation; and the digital storage device. When the stored value of the aperture value equivalent pulse once stored in the device is in the underexposure range or overexposure range, the gate is opened in response to the output of the storage stage, and the shutter time correction pulse is stored in the storage capacity of the digital storage device. We propose a shutter time priority type automatic exposure device that uses a gate circuit that allows input to either an increase input terminal or a storage capacity decrease input terminal.

Hereinafter, this invention will be explained in detail according to its embodiments.
In FIG. 1, reference numeral 1 denotes a pulse oscillator, which oscillates at a frequency corresponding to the light from the subject that is incident on the light receiving element 2. In FIG.

The oscillation frequency is determined depending on the brightness of the subject or the logarithm of the brightness. Since various types of pulse oscillators of this type are well known, the circuits will be omitted. 3 is a timer,
As shown in FIG. 2, this comprises a variable resistor 4 for setting the shutter time, a capacitor 5, a switching transistor 6, and the like.

This timer 3 has an output of "1" from the time the power supply voltage is applied until the switching transistor 6 turns on. 7 is an AND gate, and the output of timer 3 is “1”
The pulse of the pulse oscillator 1 is passed during the timer period (during the timer time).

8 is an OR gate, and 9 is a reversible shift register as a digital storage device.

This reversible shift register 9 receives the pulse output from the AND gate 7 as a right shift pulse via the 〇R gate 8, and receives the pulse output from the AND gate 10 (described later) as a left shift pulse. It's like this.

11a, 11b, . . . 11h, 11i are display members such as light emitting diodes following each stage of the shift register 9, 11a, 11b are underexposure castles, and 11c to 11g.
11h and 11i are set as appropriate castles, and overexposed castles.

That is, when the aperture value calculated from the brightness of the subject and the evening time of the set shirt is within the aperture controllable range, one of the display members 11c to 11g lights up, and the aperture value is smaller than the maximum aperture value. 11a or 1 for value
1b is lit, and conversely, when the aperture value is larger than the maximum aperture value, either 11h or 11i is lit. In the figure, the shift register 9 is shown as having nine stages, but the number of stages is determined as necessary.
Reference numeral 12 denotes an aperture drive circuit for moving the aperture 13, which includes, for example, a circuit that converts the digital output of the shift register 9 into an analog output such as voltage, and a rotation mechanism such as a meter, rotary magnet, or servo motor that operates using voltage, etc. including.

It is preferable that the diaphragm 13 is at its maximum aperture value in its initial state and is narrowed down by the frit drive circuit 12. When the aperture value stored in the shift register 9 is 4 mm below the open aperture value, the aperture 13 can remain open, so the output of that stage is not input to the aperture drive circuit 12. Reference numeral 14 denotes a clock pulse oscillator, which, as shown in FIG.

This variable resistor 15 and the variable resistor 4 are interlocked with the shutter dial. 18 is a switch that is formed at the same time as the shirt sleeve is closed.

Reference numeral 19 denotes a counter, which turns on the thyristor 20 when the count reaches a predetermined value.

21 is a zero electromagnet for closing the shutter.

When the aperture value stored in the shift register 9 is less than the open aperture value by 4, the signal is sent to A via the OR gate 22.
The voltage is applied to the ND gate 23.

On the other hand, when the stored aperture value is larger than the maximum five aperture values, the signal is sent to the AND gate 2 via the OR gate 24.
5. 38 is a flip-flop which is triggered when the output of the timer 3 returns from "1" to "0", and sends the "1" output to the AND gate 23;
and 250.

26 is an AND gate which, when receiving the output of the AND gate 23, passes the output pulse of a monostable multipipulator 37, which will be described later.

Similarly, numeral 10 is an AND gate which, when receiving the output of the AND gate 25, passes the output pulse of the single-stage stable multi/disabler 37. 27 is a shutter dial, which is linked to the timer 3 and the variable resistance of the clock pulse oscillator 14.

27 is a brush, which rotates in conjunction with the shirt dial 27.

Although not shown in the figure, a voltage is applied to this brush 28. Reference numeral 29 denotes an insulating plate arranged in the rotation area of the brush 28, and conductor parts 30 to 34 are provided at predetermined intervals.

This interval is made to match the click interval of the shirt starter dial 27, and when the shirt starter dial 27 is set to a desired shirt starter time, the brush 28 comes into contact with the insulating part.
When the shirt dial 27 is rotated by one step, the brush 28 comes into contact with a conductive part and then comes into contact with the next insulating part. 35 is an OR gate and each conductor part 30 to 34
It is designed to receive the output power of 0.

As mentioned above, since voltage is applied to the brush 28,
When the shirt time is changed by one step, one pulse is output from the OR gate 35, and when it is changed by two steps, two pulses are output from the OR gate 35 as the shirt night time correction pulse. 36 is an AND gate, which passes the output pulse of the OR gate 35 after the output of the flip-flop 38 becomes "1".

37 is a monostable multipipulator, and AND gate 36
The output pulse is triggered by the pulse output from the AND gate 10, 26.

This monostable multipipulator 37 is for waveform shaping and is not necessarily necessary. The operation of this embodiment circuit will be explained.

Set the shirt time by operating the shirt dial 27. Then, when the power switch (not shown) is closed, the timer 3 and the pulse oscillator 1 are activated, and the pulse is
The signal is input to a reversible shift register 9 via an ND gate 7 and an OR gate 8. Therefore, the signal "1" initially set in the first stage is shifted to the right in the Z direction in the figure, and the stage corresponding to the number of shift pulses becomes the output "1".
At this time, if any one of the display members 11c to 11g lights up, it means that the aperture value is within the controllable range.
That is, the aperture drive circuit 12 correctly controls the aperture 13 to the aperture 2.
It's crowded. Then, when the release button is pressed, the switch 18 is closed at the same time as the shirt cover is opened, and after the set time has elapsed, the thyristor 20 is turned on and the shirt cover is closed. If either the display member 11a or 11b lights up, it means that there is insufficient exposure even at the maximum aperture value. At this time, shift register 9
The output of is applied to AND gate 23 via OR gate 22. And the output of timer 3 changes from “1” to “0”
When returning to AN, the flip-flop 38 inverts and outputs
Send to D gate 23. Then, AND gate 23 outputs and AND gate 26 opens. shirt tadyal 2
When the brush 7 is moved one step at a time, the insulating portion and the conductive portion of the brush 28 come into contact with each other alternately, so that the OR gate 35 outputs one pulse at a time. This pulse passes through an AND gate 36 and triggers a monostable multipipelator 37. Then, the output pulse of the multipipulator 37 is AND
The signal is input to the shift register 9 via the gate 26 and the OR gate 8. Each time this pulse is input to the shift register 9, the signal shifts further to the right, and the display section 11
When c lights up, stop the shirt tadyal. At this time, the aperture value is the open aperture value. Then, by pressing the leash pin, the shirt timing will be controlled using the corrected shirt timing. When either display section 11h or 11i lights up, it means overexposure even at the maximum aperture value. At this time, the output of the shift register 9 is applied to the AND gate 25 via the OR gate 24.

Then, when the flip-flop 38 outputs, the output of the AND gate 25 is sent to the AND gate 10, so
AND gate 10 opens the gate. When the shutter dial 27 is moved in the opposite direction to that described above, that is, in a direction that increases the shutter time, a pulse is input to the shift register 9 via the AND gate 10. Therefore, each time this pulse is input, the signal shifts to the left. Then, when the display member 11g lights up, the shirt dial is stopped.
At this time, the aperture value is the maximum aperture value. Next, when the release nail is pressed down, the shirt release is controlled using the corrected shirt release time. In this embodiment, if the shutter dial is corrected, the aperture value in the digital storage device is also corrected, so there is no need to operate the timer 3, pulse oscillator 1, etc. again and perform recalculation based on the correction information. Further, in this embodiment, the set shutter time is not automatically and uniformly corrected, but the degree of correction can be arbitrarily selected depending on the shooting intention, which is convenient.

As described above, according to the present invention, when the digitally stored aperture value is out of the controllable range, a message to that effect is displayed, so that the set shutter time can be corrected.

Since the repetition period of the zero clock pulse used for shirt starter control or the count number of the counter that counts clock pulses is changed in conjunction with the shirt starter time setting section, the shirt starter time control circuit can be configured digitally. This is preferable as an interlocking mechanism. Furthermore, the amount of rotation of the shutter time setting member is converted into a digital output, and this output is used to correct the number of pulses stored in the digital storage device, so that the set shutter time can be quickly and easily corrected. , the depth of field can be selected arbitrarily depending on the shooting intention.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an automatic exposure device showing one embodiment of the present invention, and FIG. 2 is a circuit diagram showing a specific example of a timer and a clock pulse oscillator. 1. ...Pulse oscillator, 3...Timer, 9
...Reversible shift register, 11a to 11i...
...Display member, 12...Aperture drive circuit, 1
3...Aperture, 14...Clock pulse oscillator, 27...Shutter dial, 28...
... Brush, 29 ... Insulator, 30-34
・・・・・・Conductor part. Figure 1 Figure 2

Claims (1)

[Claims] 1. Equipped with a pulse oscillator that generates pulses corresponding to an aperture value calculated based on the brightness of the subject and a preset shutter time, etc., and a storage stage for an underexposure area, an appropriate area, and an overexposure area, and , a digital storage device that stores the pulses and includes input terminals for increasing and decreasing the storage amount, an aperture drive circuit that controls the aperture according to the stored value of the digital storage device, and a display that displays the stored value. a shutter time setting member that generates one shutter time correction pulse per unit rotation; and when the stored value of the pulse corresponding to the aperture value once stored in the digital storage device is in an underexposure range or an overexposure range. , a gate circuit that receives the output of the storage stage, opens the gate, and inputs the shutter time correction pulse to either the storage amount increase input terminal or the storage amount decrease input terminal of the digital storage device. Exposure device.