JPS5858526A - Aperture controller for camera - Google Patents

Abstract

PURPOSE:To make a proper exposure for a main object possible to prevent erroneous setting of a shutter speed and an aperture, by shifting automatically the aperture in a proper number of stages for the result of the automatic adjustment in case of flash photography. CONSTITUTION:When charging of the flash device side is completed and a charge completion signal is inputted to an inverter 20, an AND circuit 21 holds a low output even if the output of a comparator 6 is inverted to the high level. In case that a set shutter speed is the strobe symchronizing shutter speed, the shutter speed is controlled in accordance with the set value; and when an aperture reaches an aperture value, where the exposure is under a proper exposure by a set number of stages, in the set shutter speed, the output of a comparator 11 is inverted, and the power supply to an electromagnet 24 is broken, and thus, the aperture is adjusted to said aperture value. In case that the set shutter speed is higher than the synchronizing shutter speed, the output of a comparator 14 is inverted by a proper aperture value of the natural light, and the power supply to the electromagnet 24 is broken, and the aperture is adjusted to the aperture value at this time.

Description

[Detailed Description of the Invention] The present invention is a camera in which when the shutter speed is set, the aperture value is automatically adjusted according to the brightness of the subject, and the aperture value is adjusted by the flash device charging completion signal input from the flash device. The present invention relates to an aperture control device for a camera that switches an aperture value.

Normally, in flash photography using an eye reflex camera, the aperture value is selected by the photographer depending on the subject distance, for example, F2.8 or F5.6, and the shutter speed is the maximum synchronized shutter speed of the camera used ( Normally 1/60s
I was shooting at ec/degree). In photographs obtained by such photography, if the flash photography is done in relatively low ambient light conditions, the surroundings are mostly unexposed and in pitch darkness, and only the main subject is exposed. The result is a photograph that is far from what the photographer intended.

As a countermeasure to these problems, a method is proposed in which the photographer manually sets the shutter speed and aperture value, and then sets the shutter speed to a slow shutter speed, such as I BeC, to give exposure to the surroundings. has been done. However, with this method, the photographer has to set the shutter speed and aperture value by referring to his or her experience or the readings indicated by the exposure meter, so it is not easy to use, and there is a high possibility of incorrect settings. Met.

The present invention was devised in consideration of the above problems, and allows the photographer to set the shutter speed and automatically control the aperture to an aperture value that provides an appropriate exposure based on the set shutter speed when shooting with natural light. When a charging completion signal is input from the flash device, the automatically adjusted aperture value is controlled to underexpose, for example, by about one stop, and then the flash is emitted to obtain proper exposure for the main subject. It controls the light emission so that the

A detailed explanation will be given below based on the drawings.

FIG. 1 shows a first embodiment of a TTL flash control shutter speed priority camera circuit using the present invention. In the figure, numerals 1 and 100 are both photovoltaic elements that receive the reflected light from the subject that has passed through the photographic lens aperture, and 1 is installed near the pentagonal prism to receive the reflected light from the subject when the -eye reflex mirror is lowered.・It is arranged so that it is incident,
This is for metering the light reflected from the subject before the shutter travels. 1
Reference numeral 00 is provided near the film so that when the mirror is raised, the reflected light from the object is reflected by the shutter base or the film surface and enters the mirror, and is used for flash control.

Reference numeral 2 outputs a logarithm compression voltage of the photometric value through a high power impedance operational amplifier logarithm compression diode 3.

A sliding resistor 4 connected to both ends of a constant voltage source 5 has a sliding contact A that moves on the resistor 4 according to the set film sensitivity, and generates a voltage that is the sum of the photometric value and the film sensitivity information, that is, in terms of Apex calculation. A voltage corresponding to (BV-1-8V-AV) is output from point B. (BV is the brightness value of the subject, SV is the set film sensitivity value, and AV is the value of the aperture aperture through which the subject light passes) Sliding resistor 7 connected to both ends of constant voltage source 8
The sliding contact C moves on 7 according to the set shutter speed, and a voltage corresponding to the set shutter speed is output from the 0 point. The sliding resistor 9 connected to both ends of the constant voltage source 10 is a sliding resistor that adds a shift signal to the aperture control signal, and is a resistor that sets the number of steps at which underexposure occurs due to natural light. , for example, the setting is set to underexpose by one stop, and the set shutter speed is set to 1 stop.
/2 sec, a voltage corresponding to ISθC0 is output. Of course, the set number of stages may be fixed. Further, from point D, a voltage corresponding to the highest strobe synchronization shutter speed is output. In the comparator 15, a voltage corresponding to the set shutter speed is input to the ten terminals, and a voltage corresponding to the fastest strobe synchronization shutter speed is input to the first terminal, and when the set shutter speed becomes faster than the synchronization speed, the output is ``'' H″Leherninal. 6.
11. 141. With the i converter vertical, the voltage at point B decreases when the aperture is stopped down, and when the aperture value reaches the aperture value that allows proper exposure in natural light for the set shutter speed, the output of the 6 changes from the "L" level to the ``H'' level. The voltage is reversed. 11 is when the aperture of the diaphragm reaches an aperture value that is under the set number of exposure steps in natural light compared to the set shutter speed, the voltage will change from the "L" level to the @H" level. Even though the voltage at point D, that is, the voltage corresponding to the highest tuned shutter speed, is still connected to both ends of the constant voltage source 13, the sliding resistor 12 causes the voltage corresponding to a shutter speed that is one step lower than the setting to F. 14 is the output when the aperture value reaches an aperture value that is under the set exposure number of steps in natural light compared to the fastest flash synchronized shutter speed.
The voltage is inverted from the L@ level to the "H" level voltage.

When a flash device charge completion signal is not input from the flash device side (not shown), no flash is emitted, and the input of the inverter 20 remains at the "L" level, so the output of the inverter 20 is set at the "H" level. When the aperture reaches an aperture value that provides proper exposure at the shutter speed, the AND circuit 21.
The output of the OR circuit 23 is inverted to the "H" level, power to the aperture control electromagnet 24 is cut off, and the aperture is adjusted to the aperture value at that time. Next, when charging on the flash device side is completed and a charging completion signal of H" level is input to INNO (-20), the AND circuit 21 Maintain the ``L'' level.

When the set shutter speed is the strobe synchronization shutter speed, the shutter speed is controlled according to the set value, and the aperture aperture reaches the aperture value at which the exposure is underexposed by the set number of steps at the set shutter speed.Sult comparator 11
The output power of inverter 17 is inverted to H'' level, and the output of comparator 15 is at L level, so the output of inverter 17 is @
At H'' level, AND circuits 16, 22, OR circuit 19.
23 is inverted to the "H" level, power to the electromagnet 24 is cut off, and the aperture is adjusted to an underexposure aperture value. When the set shutter speed is faster than the synchronized shutter speed, the output of comparator 15 is
Since the output power of INNO (-17) is 1L'', the AND circuit 16 closes and the AND circuit 18 opens, and the output of the comparator 14 is reversed to H'', that is, the printer speed is lower than the synchronized speed due to the sliding resistance 12. The shutter speed is delayed by the set number of steps to give proper exposure in natural light, and when the aperture is stopped down to the aperture value, the output of the comparator 14 is inverted to "H", and the AND circuit 1B, the OR circuit 19, and the AND circuit 22 After that, the magnet 24 is de-energized and the aperture is adjusted to the value at that time.

Next, in synchronization with the start of the first curtain run of the shutter, the count switch 103 is opened, the photometric value by the photovoltaic element 100 is expanded by the transistor 101, and the integration of the expanded current by the integrating capacitor 102 is started. Furthermore, when the shutter curtain is fully opened, the flash discharge tube starts emitting light, and when the exposure amount reaches an appropriate level, the output of the comparator 104 becomes "
The signal is inverted to H'' level, and the signal is transmitted as a flash emission stop signal to the flash unit (not shown) to stop the flash emission.In this way, the flash emission control is performed by film surface photometry.

FIG. 2 is a second implementation 91 of a TTL strobe controlled shutter speed priority camera using the present invention. 1st
In the camera shown in the figure, the aperture is controlled to be several stops under the set shutter speed to give exposure to the periphery of the subject, and the main subject is given the proper exposure by emitting fXj light. However, in this embodiment of the car camera, we set the camera speed and speed; considering that we are shooting a subject in a backlit scene such as daylight synchronization, we set the aperture under natural light and adjusted the aperture to overexpose by the set number of stops. and then emit a flash. I mean,
In backlit scenes, the brightness of the subject is normally affected by the backlight (for example, the brightness is extremely high, such as BV8 or higher, and the aperture value for proper exposure at that brightness is FIL or higher, and the main subject is in a shadow due to backlighting and has low brightness.) Even if you try to get the correct exposure by flashing, the aperture 9 will be closed too close and the amount of light will not be enough with the normal flash firing ability.For this reason, with this camera, if you set the shutter heat filter synchronization speed to a higher speed, The aperture is adjusted so that the surrounding area is overexposed with only natural light. In the figure, a sliding resistor 2 is connected to both ends of a constant voltage source 13.
5 is a resistor that sets the number of steps to ensure that the surrounding area is auto-exposed <- under natural light.The maximum flash synchronization shutter speed output to the flash is 1/60 seconds, and the number of overexposure steps is 2 steps. Then, from point G, the phase is 1/250 seconds,
The corresponding voltage is output. When the flash device charging completion signal is input and the set shutter speed is faster than the synchronization speed, the output of the comparator 15 becomes II B IT.
When the aperture is reversed to the level, the AND circuit 16 is closed, and the aperture 18 is open, and the aperture is narrowed down to the aperture that will cause overexposure by the set number of steps at the highest synchronized shutter speed (i.e., the aperture value that will give the correct exposure at l / 250 seconds). Since the output of the contactor 18 is also reversed to the 1H" level, the power to the aperture stone 724 is cut off, and the aperture is adjusted at the aperture value at that time. The same symbols are given and the explanation is omitted.

FIG. 43 shows a third embodiment of a TTL strobe control aperture-priority camera circuit using the present invention, which is a camera in which the aperture value is set with priority and the shutter speed is automatically controlled to obtain proper exposure.

In the figure, 26 is a sliding resistance in which the sliding contact moves according to the number of steps from the set aperture value to the open aperture, and from point 1, the voltage output from point B when the aperture is narrowed down to the set aperture value. The same voltage is output in the open aperture state. Reference numeral 27 is a memory switch which is opened in synchronization with the camera release just before the aperture narrowing operation starts. When the strobe charging completion signal is not input from the strobe side, the logarithmic compression voltage of the photometric value stored in the memory capacitor 28 is transferred to the expansion transistor 3 via the inverter 29.
0 and integrated by the counting capacitor 32. When the integrated value reaches a certain level, the output of the comparator 33 is reversed to the 1H" level, the electricity to the shutter speed control electromagnet 34 is cut off, and the shutter second curtain runs. In this way, the shutter speed is controlled to obtain the proper exposure at the set aperture value.

- The sliding resistor 35 connected to both ends of the constant voltage source 36 is a resistor that sets the number of underexposure steps due to natural light, and from the point, the output voltage of the buffer 29 is increased by a voltage corresponding to the number of underexposure steps. The voltage added to is output. The constant voltage source 38 outputs a voltage corresponding to the fastest strobe synchronization shutter speed. The output of the constant voltage source 38 and the voltage at point K are input to the comparator 37, and when the voltage at point K is higher than the voltage at point 38, the shutter speed corresponding to the voltage at point is higher than the strobe synchronization shutter speed. When the speed increases, the output of the comparator 37 is '
It becomes "H" level. Now, with the aperture set as mentioned above,
If the shutter speed that results in underexposure in natural light by one step of set exposure is faster than the strobe synchronization speed, the output of the comparator 37 becomes H" level, and if the strobe charging completion signal is input, the AND circuit 47 The output also becomes @H'' level, transistor 49 is turned on, and transistor 50 controls the shutter at the maximum strobe synchronized shutter speed. The main subject can be properly exposed by flashing the flash. Next, if the shutter speed corresponding to the voltage at the point is the strobe synchronization shutter speed, comparator 3
7 maintains the 1L" level, and the output of the inverter 39 becomes the 1H" level, so the output of the AND circuit 43 also goes to the "H" level, the transistor 45 is turned on, and the shutter speed is set at the set aperture value. The shutter speed is controlled to underexpose the set exposure by one stop in natural light, and the main subject is properly exposed by firing the strobe.

FIG. 4 is a fourth embodiment of a TTL strobe control shutter speed priority camera circuit using the present invention. In this camera, the number of underexposure steps (overexposure) due to natural light is not fixed to a fixed value, but changes depending on the brightness of the subject.If the subject is dark, the number of underexposures (overexposure) due to natural light is changed by one step to make the surroundings dark. On the other hand, if the subject is extremely bright, the number is increased, and if the subject is extremely bright, the daytime synchronization is considered to be the target subject and the exposure due to natural light is controlled to the over side.

In the figure, the sliding resistor 76 connected to both ends of the constant voltage source 7'7 is a resistor that inputs information about the maximum aperture value of the photographing lens, and from point M onwards, only the brightness of two objects is input that does not depend on the aperture value of the photographic lens. The corresponding voltage is output, and the memory switch 78 is opened by the camera release before the aperture starts.
The voltage at point M is stored in memory capacitor 79. The voltage of the memory capacitor 79 passes through a buffer circuit 80, and a voltage corresponding to the subject brightness is outputted from the buffer circuit 80.

A constant voltage source 51 outputs a voltage corresponding to the subject brightness, which is a reference for determining the number of underexposure steps, and resistors 52, 53, 5
5, 56, 57. A buffer 80 corresponding to the brightness of the subject is converted from the output voltage of the constant voltage source 51 using an operational amplifier 54°58.
A voltage obtained by subtracting the output voltage of is output from the operational amplifier 58. The sliding resistor 59 is a resistor that determines the degree of change in the number of underexposure steps (or the number of overexposure steps) that changes according to changes in subject brightness, and the voltage corresponding to the number of underexposure steps (or the number of overexposure steps) is set at the L point. is output from. The voltage at the 0 point corresponding to the set shutter speed is resistor 62, 63, 65
, 60, 66 and operational amplifiers 64 and 67, the voltage at point L is subtracted, and the result is output from operational amplifier 6'7. The voltage at point D, which corresponds to the fastest strobe synchronization shutter speed, is determined by resistors 68.69, 71.72 and operational amplifier 70.
73, the voltage at the L point is similarly subtracted, and the result is output from the operational amplifier 73. When the charging completion signal is not input from the strobe side, when the aperture reaches the aperture value that allows proper exposure at the set shutter speed, the comparator 16 is inverted to the "H" level, and the aperture value is inverted to the "H" level. The power supply to the lens 24 is cut off, and the aperture is adjusted to the aperture value at that time.

If the charging completion signal is input from the strobe side,
When the set shutter speed is the strobe synchronization speed, the output of the comparator 15 maintains the L'' level, so when the aperture reaches an aperture that is underexposed (or overexposed) by the amount corresponding to the brightness of the subject at the set shutter speed, the output of the comparator 74 is The output is inverted to the IIH1'' level and aperture control is performed. Next set up
When the speed is faster than the strobe synchronization speed, the output of the comparator 15 becomes "H" level, and when the aperture reaches the aperture that underexposes (or overexposes) by the amount corresponding to the brightness of the subject at the fastest strobe synchronization shutter speed, the output of the comparator 75 changes. The output is inverted to the 1H'' level and aperture control is performed. FIG. 5 is a diagram showing the position of the light receiving element provided in the camera of the present invention.

In the figure, 107 is a photographing lens, 106 is a mirror, 1
05 indicates a prism, 1) is a light receiving element for metering the reflected light from the subject when the mirror is down, and 100 is a mirror up.
This is a light-receiving element for photometering the reflected light from the subject.

The device of the present invention is a camera with the above-mentioned configuration in which when either the aperture or the shutter speed is set, the other is automatically adjusted, and in the case of flash photography, the aperture is set to the underexposure side (as compared to the result of the above automatic adjustment). The system automatically shifts the appropriate number of steps to the overexposure side (in the case of normal flash photography) or overexposure (in the case of daytime sync □ mouth photography), so the camera user can perform normal flash photography by performing the same operations as in normal photography. In this case, it is possible to obtain an exposure that is close to appropriate even when compared to the surrounding background, and this eliminates the situation where the aperture is too narrow during daytime synchronization and the main subject cannot be adequately exposed. Since no special operation is required to obtain the desired effect, it is possible to provide a camera that can be used by anyone and prevents erroneous shutter speed and aperture settings. )

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIGS. 1 to 4 are circuit diagrams of four different embodiments, and FIG. 5 is a side view showing the arrangement of photovoltaic elements. 1.100...photovoltaic element, 6. 11. 14.
15... Comparator, 4... Film sensitivity setting [iJ low resistance 9... Sliding resistor for setting the number of steps under the aperture, 12... Sliding resistor for shutter speed signal shift,
24... Magnet for aperture setting. Agent Patent Attorney Kosuke Hayashi

Claims (3)

[Claims] (1) In a circuit that sets either the shutter speed or aperture and automatically adjusts the other, a circuit is provided that adds a shift signal for the appropriate number of steps to the aperture control signal, and a charging completion signal is input from the flash device. An aperture control device for a camera, in which aperture control is performed by the output of a circuit that adds the shift signal when the shift signal is added. (2) If the shutter speed is determined faster than the maximum flash device sync speed, the shift signal will be on the overexposure side; if the shutter speed is determined to be slower than the maximum flash device sync speed, the shift signal will be on the underexposure side. An aperture control device for a camera according to claim 1, wherein: (3) Equipped with a circuit that outputs a shutter speed control signal corresponding to the maximum flash device synchronized shutter speed, and when a charging completion signal is input from the flash device, an appropriate aperture value signal is formed by the output of this circuit; An aperture control device for a camera according to claim 1 or 2, wherein a shift signal is added to the aperture value signal.