JPS59208534A - Diaphragm control device of program type camera - Google Patents

Abstract

PURPOSE:To execute a stop-down control without using a full-aperture F-number by calculating a stop-down quantity detecting quantity so as to satisfy a prescribed program, comparing it with a photometric output, and stopping a stop-down operation. CONSTITUTION:An output of a photodetector 3 corresponding to light quantity of an object to be photographed, which passes through a diaphragm stopped down from the maximum diaphragm aperture to the minimum diaphragm aperture becomes a photometric voltage through a logarithmic operational amplifier 4 and a film sensitivity correcting operational amplifier 6 and it is applied to a comparator 12. On the other hand, this photometric voltage is a applied to a stop-down operating voltage generating circuit 13, too, and in accordance with a stop-down detecting voltage, etc. by the circuit 13, an operational amplifier 15 for calculating a program constant calculates voltage corresponding to a photometric value corresponding to a diaphragm step number based on a shutter second time and applies it to the amplifier 12. As a result, a solenoid 19 is degaussed by a coincidence output of the amplifier 12 and the diaphragm operation is stopped. According to this constitution, a diaphragm control is executed without using a full-aperture F-number through a mechanism interlocking with the diaphragm.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an aperture control device for a programmable camera, and more particularly, an aperture control device for a programmable camera in which aperture control is performed to an aperture value determined by predetermined program characteristics in response to subject brightness. Regarding a control device.

Conventionally, in programmable single-lens reflex cameras that perform aperture control based on predetermined program characteristics,
It is necessary to introduce the aperture F value of the photographic lens as exposure information, and this aperture value and the T value at the aperture of the lens
A subject brightness value is calculated from TL (Through the Lens) 1llll+original value, and an aperture value and a shutter speed value are determined from this subject brightness value based on predetermined program characteristics. That is, when performing aperture control, once the aperture is opened, TTL photometry is performed and the photometry value is memorized, the aperture is stopped down, and the TTL photometry value that passes through the aperture during this narrowing operation is used as the stored aperture value. The photometric value at the aperture is compared with a fixed value calculated based on the value, and when the two match, the aperture stop magnet is driven to stop the aperture operation. Therefore, conventional programmable cameras has a transmission member for transmitting the aperture F value of the photographing lens to the camera side, and for cameras that are not provided with the transmission member, aperture control cannot be performed based on predetermined program characteristics.

In view of the above points, it is an object of the present invention to compare the photometric output that has passed through the diaphragm during the aperture operation and the calculated output that is obtained by calculating and inverting the photometric output so that it satisfies predetermined program characteristics. An object of the present invention is to provide an aperture control device for a programmable camera, in which the aperture value is controlled to an aperture value based on a predetermined program characteristic when the Ryokawa forces match.

According to the present invention, aperture control is performed based on predetermined program characteristics even in a camera that does not have a transmission member for introducing an open F-number.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on illustrated embodiments, but before describing the embodiments, the principle of the present invention will first be explained using calculation formulas.

Now, when determining the program characteristics for the aperture control device according to the present invention, as shown in FIG.
- Program characteristic line Po, which is one of the basics in the AY coordinate system
Assume that This program characteristic line Po is AV=A,V
Based on the straight line o, the point (α.

AVo) and a straight line 1□ with a slope γ. The straight line 2 of the slope γ is AV − AV6 = 7” (T V − α) −
-----(Represented by 11. Here, TV:=α is the level of the aperture opening limit point, and AV=AV0 is the aperture value at that time, that is, the opening F value ( For example, the apex value is AVo=1).The aperture opening limit level α may be set, for example, to the camera shake limit seconds.Also, γ is the shutter seconds value T
This shows how many steps the aperture value AV changes when V changes by one step.

On the other hand, if the exposure information of aperture value AV, subject brightness value Bv, film sensitivity Wb' SV, and shutter time value TV is expressed as an apex value, then from the relationship of the exposure information, AV-BV+5V-TV ------- (2) holds true. Therefore, from equations (1) and (2) above, BV+
5V-TV-AVo=r(TV-α) ``''(3), so from this equation (3), (1+r)'rV=BV+5V-AV0+ar,','
rV= 7□, -(BV+5V-AVo+αr)---
--(41).In other words, this formula (4) is the basic formula for the program characteristic line Po, and once the subject brightness value BY and film sensitivity value Sv are determined, the shutter time value TV can be determined. By substituting this equation (4) into the above equation (27), it can be determined that the aperture value A
Therefore, when the aperture value AV is obtained, the number of aperture steps ΔAV from the open aperture is JAV=AV-AY, -----(6), so this (6) Substituting the above equation (5) into the equation, Δ
Av==-(BV+SV-α-A, VO) ------
(711+γ) That is, it is clear that if the subject brightness value BY and the film sensitivity value Sv are determined from equation (7), the number of aperture stages ΔAV can also be determined.

Here, let us assume that the aperture is actually starting to narrow down to the minimum aperture diameter, and the number of aperture steps from the open aperture during this narrowing operation is ΔA V ac
t, the light amount BV' at that time is BV/=
BY−AV+1−ΔAV −−−−−(8) ct Therefore, by adding the film sensitivity value SV to the value of this equation (8), BV′+5V = BV+5V−AV, −ΔAY −−−−−( 9)
ct.

Therefore, if we intentionally create a signal such as ΔAV
...(12). That is, the above equation (9) and (
When both signals expressed by equation (10) and equation (11) satisfy the above equation (11), at this time, the number of aperture stages ΔAVaot during the aforesaid aperture operation reaches the number of aperture stages ΔAV that satisfies the above equation (7). Become. Therefore, even if the subject brightness value BV is not known, the amount of light BV' during the aperture operation, the film sensitivity value SV, and the number of aperture steps Δ during the aperture operation.
If a determination is made based on the AVact signal and the aperture operation is stopped when the two match, aperture control can be performed based on the P4 Dalam characteristic line PoK.

Next, the present invention will be explained in detail based on the principle of the present invention described above.

FIG. 2 is an electrical circuit diagram of an aperture control device for a programmable camera showing an embodiment of the present invention. A light receiving element 3 having a photoelectric conversion function such as a 5BC (silicon blue cell), which is placed in a position in the camera where it can receive the subject light passing through the photographing lens 1 and the aperture 2, is an inverting input terminal of an operational amplifier 4 for a photometric circuit. and the non-inverting input terminal, with the anode side facing the non-inverting input terminal. A logarithmic compression diode 5 is connected between the inverting input terminal and the output terminal of this operational amplifier 40 with its anode side facing the output terminal. The non-inverting input terminal of operational amplifier 4 is grounded,
The output terminal is connected to a non-inverting input terminal of an operational amplifier 6 for introducing film sensitivity information in the next stage. The inverting input terminal of the operational amplifier 6 is connected to the output terminal of the operational amplifier 6 via a variable resistor 7 for setting a film sensitivity value, and is also connected to the collector of an NPN transistor 8.

The base of the transistor 8 is connected to the base and collector of an NPN transistor 90, and the collector is connected via a resistor 10 to a terminal 11 to which a power supply voltage of 1 Vcc is applied. The emitter of transistor 8.9 is grounded. This circuit consisting of transistors 8 and 9 forms a well-known current mirror circuit by using transistors 8 and 9 with the same characteristics, and the collector of transistor 8 is connected to the variable resistor for setting the film sensitivity value. 7, a constant current ■ equal to the collector current of transistor 9; I try to let it flow.

On the other hand, the output terminal of the operational amplifier 6 is connected to the comparator 12.
5. is connected to the inverting input terminal of the 5. It is connected to the. The output terminal 0 of the narrowing down operation voltage generating circuit 16 is connected to the inverting input terminal of the operational amplifier 15 for program constant calculation via the slope adjusting variable resistor 14 for determining the slope r. A resistor 16 is connected between the inverting input terminal and the output terminal of the operational amplifier 1150, and the output terminal of the operational amplifier 15 is connected to the non-inverting input terminal of the comparator 12.

Further, a sliding terminal of a variable resistor 17 for setting a reference voltage connected between the power supply voltage terminal 11 and ground is connected to the non-inverting input terminal of the operational amplifier 15 and the narrowing operation voltage generating circuit 13. The reference voltage setting variable resistor 17 is used to determine the aperture opening limit level α, and a reference voltage Va proportional to the aperture opening limit level α is guided to the aperture operating voltage generating circuit 13 and the operational amplifier 15. The output terminal of the comparator 12 is connected to the power supply voltage terminal 11 via the aperture control magnet coil.

Next, the operation of the aperture control device shown in FIG. 2 will be described.

When the subject light passes through the photographic lens 1 and the aperture 2 and is received by the light receiving element 3, the light receiving element 3 performs photoelectric conversion, and a voltage VB y/, which is logarithmically compressed amount of light received, is applied to the output terminal of the operational amplifier 4. Output. This voltage vnv' is a voltage proportional to BV' shown in equation (8) above. When this voltage VBvt is led to the non-inverting input terminal of the operational amplifier 6, a constant current I
0 is flowing, so the resistance value of this variable resistor 7 is Rsv
Then, "sv"'Rsv・■. The voltage is the above voltage V
In addition to B V /, the output terminal of the operational amplifier 6 has a voltage VBvl corresponding to the above BV' -) - SV.
+sv is output. The output of this operational amplifier 6 is led to an inverting input terminal of a comparator 12 on one side, and to a narrowing operation voltage generation circuit 13 on the other hand. Since the reference voltage va is led to this narrowing down operating voltage generating circuit 13, the narrowing down operating voltage generating circuit 13 generates a voltage proportional to the number of narrowing stages ΔAV during the narrowing down operation from the output voltage VBV' + BY of the operational amplifier B. voltage v
Create JAv, 6t, output ct, and apply the above reference voltage V. The voltage V∆AVact minus the voltage V7Av, 6t is output to the output terminal 0. This voltage--VJAVaet is the variable resistor 14
Since the reference voltage Va cannot be led to the inverting input terminal of the operational amplifier 1150 through the inverting input terminal of the operational amplifier 1150, the resistance value of the variable resistor 14 is connected to the output terminal of the operational amplifier 15. If Rr is selected for the resistor 16, this voltage will be the signal α-1-1ΔAVaotγ ■a+±ΔAvact is led to the non-inverting input terminal of the operational amplifier 2, and the operational amplifier 12 will output the output voltage VBV'+SV of the operational amplifier 6. compared to

By the way, the output voltage of the operational amplifier 6 mentioned above ■BV'+SV
As shown in FIG. 6, the voltage decreases with the passage of time t, and since the output of the operational amplifier 6 is inverted for calculation, it rises with the passage of time t. That is, if the subject is bright enough, as shown in FIG.
The output becomes "L" level, the aperture control magnet coil 18 is energized, and the aperture 2 starts to narrow down. As the aperture 2 is narrowed down, the output voltage VBV' of the operational amplifier 4 decreases, so the output voltage 'BY' of the operational amplifier 6 decreases.
EV also decreases as shown in Fig. 3, but the number of narrowing stages Δ during narrowing down operation is
Take out the voltage VΔAVast corresponding to Avact,
The output voltage V of the operational amplifier 15 is calculated by calculating the aperture opening limit level α and the Purgram constant of the slope r.
a+-LΔAvaat increases as the aperture 2 narrows down, and s vBV'+sv≦Vα+-! −Δ
When AVaet is reached, at this point the output of the comparator 12 changes from the I'LI level to the @H'' level, the aperture control magnet coil/I/18 becomes de-energized, and the aperture 2 stops the aperture 2.Op-amp At this time, the aperture is controlled to the aperture value AV on the program characteristic line P0 shown in FIG. 1, which corresponds to the subject brightness.Incidentally, in FIG. The point in time when the output of the operational amplifier 15 matches and the aperture stops is the point in time when the amount of level change of both the output voltages of the operational amplifiers 15 and 612- from the start of the aperture becomes 1:r.

Next, examples of specific circuit configurations of the narrowing down operating voltage generating circuit 13 are shown in FIGS. 4 to 6, respectively.

In the narrowing operation voltage generating ports 1ij, lsA shown in FIG. 4, the input terminals connected to the output terminals of the operational amplifier 6 are connected in series with resistors 21. It is connected to an inverting input terminal of an operational amplifier 23 via a capacitor 22, and the inverting input terminal is connected to an output terminal of an operational amplifier 25 via a resistor 24. Therefore, the capacitor 22, the resistor 24, and the operational amplifier 23 constitute a differentiating circuit. The output terminal of the operational amplifier 23 is connected to the inverting input terminal of the operational amplifier 26 via a resistor 25, and the inverting input terminal is connected to the output terminal of the operational amplifier 26 via a resistor 27, a capacitor 28, and a parallel circuit. There is. Therefore,
A 25° resistor, a capacitor 2, and an operational amplifier 26 constitute an integrating circuit. The output terminal of this operational amplifier 26 is an output terminal 0 connected to the variable resistor 14 for adjusting the slope. The non-inverting input terminals of the operational amplifiers 23 and 26 are connected to the reference voltage V mentioned above. is connected to the sliding terminal of the variable resistor 17 so that .

In this narrowing operation voltage generation circuit 15A, when the output voltage VBv/+8v from the operational amplifier 6 is introduced to the input terminal I, the voltage vBv/+sv is first differentiated at the operational amplifier 23 in the previous stage. That is, when the capacitance of the capacitor 22 is C3 and the resistance value of the resistor 24 is R, the output voltage of the operational amplifier 23 is V. 1 is Vol=
v(1'+R+ (VBV/+8V) ”-(1
3) dt becomes. When this voltage V01 is led to the operational amplifier 26 in the next stage, integration is performed in the operational amplifier 260. Therefore, if the resistance value of the resistor 25 is R2 and the capacitance of the capacitor 2 is 02, the output voltage of the operational amplifier 26 is Oxke, becomes .

Here, d t (■nv' +
sv) is nothing but the speed of narrowing down. Therefore, this corresponds to (14) above. However, f stones (VBv r,
, )dt is a negative voltage in terms of the circuit, so the following equation is obtained. Therefore, the above equation (14) is C, R, , = C2
If R2, vo, = va-v, ^v,, tsee *°(16
).

In addition, in the narrowing down operation voltage generating circuit 13B shown in FIG.
The non-inverting input terminal is connected to the next-stage operational amplifier 3 via a storage capacitor 33.
4 and a variable resistor 170 sliding terminal to which the reference voltage Va is applied. The inverting input terminal of the operational amplifier 32 is connected to an output terminal, and the output terminal is connected to the inverting input terminal of the operational amplifier 1340 via a resistor 35. Further, the inverting input terminal of this operational amplifier 34 is connected to the operational amplifier 34 which is the output terminal 0 via a resistor 36.
The non-inverting input terminal is connected to the input terminal (2) via a resistor 37.

In this aperture operation voltage generation circuit 13B, the aperture start interlocking switch 31 is closed before the aperture 2 starts narrowing down, and the output voltage VB of the operational amplifier 6 is
It is led to the non-inverting input terminal of the operational amplifier 32 through the v/+8v switch 31 and to the non-inverting input terminal of the operational amplifier 34 through the resistor 67.

The inverting input terminal of the operation switch 1340 is connected through a resistor 65.
A voltage obtained by inverting the voltage at the non-inverting input terminal of the operational amplifier 32 is derived. When the interlocking switch 31 is turned off at the time of starting narrowing down, the capacitor 33 stores the output voltage vnv'+sv immediately before starting narrowing down, and the voltage -vBY'+SV, which is the inversion of the same voltage, is the output voltage of the operational amplifier 32. is extracted as. Then, as the narrowing down is performed, the voltage at the input terminal I during narrowing down becomes VBY' + 5v - VΔAVaet K, so if the resistors 35 to 37 are all made to have the same resistance value, the output of the operational amplifier 34 The terminal has (■α+V
BV'+8V 'JAVaet) -VBY' +
8V ='(! -vlAV aet voltage is output.

Further, the narrowing operation voltage generating circuit 150 shown in FIG. 6 is composed of a capacitor 41. That is, one end of the capacitor 41 is the input terminal I connected to the output terminal of the operational amplifier 6, and the other end of the capacitor 41 is the output terminal 0 connected to the slope adjustment variable resistor 14. , the capacitor 41 is directly connected to the reference voltage V. It is not connected to the variable resistor 17 for giving . This capacitor 41 is always connected to an operational amplifier 15.
The difference voltage (VBv/+8v-va) between the output voltage vBY' +sv of the operational amplifier B and the voltage - of the non-inverting input terminal of the operational amplifier 15 is applied through the resistors 14 and 16 connected to the
is charged with an electric charge proportional to . For this reason, now
The aperture 2 is narrowed down and the voltage at the input terminal becomes VΔAVa□
Assuming that the capacitor 41. If the time constants of variable resistor 14 and resistor 16 are much thicker than the narrowing down time, the voltage at output terminal 0 will also be vJA.
This results in a decrease of only Vaet. Therefore, as a result, the voltage at the output terminal O becomes va''JAVact.

FIG. 7 is an electrical circuit diagram of an aperture control device showing another embodiment of the present invention. In the aperture control device shown in FIG. 7, an information addition circuit operational amplifier 55 circuit and an inverting amplification operational amplifier 60 circuit are provided between the output terminal of the 1llll+ optical circuit operational amplifier 4 and the inverting input terminal of the comparator 12. In addition, the output of the operational amplifier 4 is directly connected to the narrowing operating voltage generating circuit 13A having the circuit configuration shown in FIG.
KS ('). In other words, this aperture control device's
To explain the differences from the aperture control device described above, the output terminal of the operational amplifier 4 is connected to the inverting input terminal of the operational amplifier 55 via a resistor 51, and one end of the resistor 21 is connected to the input terminal of the aperture operating voltage generating circuit 13A. It is connected to the. Operator 1550 inverting input terminal is resistor 5
2.53, it is connected to a terminal 56 to which a voltage Bv proportional to the film sensitivity value SV is applied, and a terminal 57 to which a correction signal Vx to be described later is applied. Further, the inverting input terminal of the operational amplifier 55 is connected to the output terminal of the operational amplifier 55 via the resistor 54, and the output terminal is connected to the inverting input terminal of the operational amplifier 600 for inverting amplification via the resistor 5B.

The inverting input terminal of the operational amplifier 60 is connected to the output terminal via the resistor 59, and the output terminal is connected to the inverting input terminal of the comparator 12. The non-inverting input terminals of the operational amplifiers 4 and 55.60 are both connected to a terminal 50 to which a reference voltage VR□ is applied. Also,
Operational amplifier 23 of the narrowing operation voltage generation circuit 13A,
The non-inverting input terminal 26 and the non-inverting input terminal of the program constant calculation operational amplifier 15 are also connected to the terminal 50 to which the reference voltage V is applied. In order to determine the aperture opening limit level α with this operational amplifier 15, a terminal 62 to which a reference voltage -va is applied is connected to the inverting input terminal of the operational amplifier 15 via a resistor 61.

In the above aperture control device, the output voltage of the operational amplifier 4 is a voltage VBvl proportional to BV/ shown in the above equation (8), as in the embodiment shown in FIG. 55, if the resistance values of the resistors 51 to 54 are all equal, the information guided through each of the resistors 51 to 53 is added as is. To be precise, the output voltage of the operational amplifier 55 is
VRl, F+VBv! However, since each operational amplifier of this diaphragm control device is based on the voltage VR, the description will be made without referring to the reference voltages VRF and F for convenience.

If the open F value is not introduced now, the terminal 57
Since the correction signal Vx, which will be described later, is not applied to KVi, the voltage vBv/t and the voltage V8v corresponding to the film sensitivity value Sv are added, and the output voltage of the operational amplifier 55 is -vEv/+sv corresponding to BV/+SV. The voltage will be output.

When this output voltage is led to the operational amplifier 60 through the resistor 58, by making the resistance values of the resistors 58 and 59 equal, the output of the eleven operational amplifiers 55 is inverted, so the output voltage of the operational amplifier 60 is "vBY' -1- BY and is led to the inverting input terminal of the comparator 12.

When the output voltage VBv/Fi of the operational amplifier 4 is led to the narrowing operating voltage generating circuit 13A through the resistor 21, it is the integral of the output speed of this narrowing operating voltage generating circuit 13A, which corresponds to the number of narrowing stages. When the output of the operational amplifier 26 is led to the operational amplifier 15 through the slope adjustment variable resistor 14, the operational amplifier 15 adds it to the reference voltage -va which is led through the resistor 61. If R is equal to the resistance value, the output voltage of the operational amplifier 15 is the output voltage of the operational amplifier 26 -vJAVaet and the reference voltage/voltage -
va and the voltage V (! + ΔAVa
It becomes at.

γ Therefore, in the case of the above aperture control device, as in the case of the above embodiment, when the subject is bright and the aperture 2 is narrowing down, the output voltage of the operational amplifier 60 and the output voltage of the operational amplifier 15 are as shown in FIG. When the output voltages change as shown and both output voltages match, that is, VBY, +8v≦V,
When f+1JAVactK is reached, the narrowing down of the aperture γ2 is stopped, and at this time, the aperture control is performed according to the program characteristic line P0 shown in FIG.

Note that when the aperture control device of each of the above embodiments performs aperture control as described above, ideally the voltage at the inverting input terminal of the comparator 12, that is, the operational amplifier 6.6
0 output voltage VBv/+8v and the voltage at the non-inverting input terminal of the comparator 12, that is, the output voltage of the operational amplifier 15
+±ΔAv, ct means γ as shown in Fig. 8. If the diaphragm stops reliably when both output voltages match, the voltage vBY/+8v will be maintained at the predetermined level a [maintained] at the same time. It will be.

However, in reality, due to the delay in cutting off the aperture control magnet, the play of the aperture lever, the aperture blades, etc., as shown in Fig. does not stop, and therefore the voltage VBV'
This results in narrowing down to a state where +BY is further lower than the predetermined level a. Therefore, in such a case, correction can be made by increasing the value of the aperture opening limit level α among the program constants, or by adjusting the value of the slope r. Reference voltage V. When the value of the aperture opening limit level α is increased, the voltage Va+ΔAVaat changes from the state shown by the broken line to the state shown by the solid line, as shown in FIG. 10, and the voltage at both input terminals of the comparator 12 increases. The point at which they match becomes earlier, so
The aperture can be stopped when the voltage vBvl+Sv reaches a predetermined level a. Furthermore, even if the values of K and slope γ are reduced by adjusting the voltage Rr as shown in FIG. 11, the state shown by the broken line changes to the state shown by the solid line. It will stop. Rather than changing the aperture limit level α,
It is preferable to perform the above correction by changing the slope r since the program characteristics are not changed much. In particular, as the aperture speed becomes faster, it becomes proportional to ΔAvact, so that appropriate aperture correction corresponding to the number of aperture stages and speed can be made by only correcting the slope γ. Note that r is corrected by the resistance value R of the tilt adjustment variable resistor 14.

The narrowing operation voltage generation circuit 1
6, when the narrowing operation voltage generating circuit j3A consisting of the above-mentioned differentiating circuit and integrating circuit is used, γ may be corrected by changing the time constant of.

In addition, if you want to use the above aperture control device to perform so-called super automatic exposure control, in which the aperture is further reduced by an amount corresponding to the brightness of the subject after the aperture has been reduced to a predetermined number of stops, An electric circuit as shown in FIG. 12 is added to, for example, the electric circuit of the aperture control device shown in FIG. 7. That is, in the electric circuit shown in FIG. 12, the sliding terminal of a variable resistor 66 for ultra-automatic exposure level setting connected to a power source 65 is connected to a non-inverting input terminal of a comparator 67; The terminal is connected to the output terminal of the operational amplifier 15. and,
An analog switch 68 is connected between the output terminal of the operational amplifier 23 of the differentiating circuit and the resistor 25 of the integrating circuit, and the output terminal of the comparator 67 is connected to a control terminal of the analog switch 68. Therefore, in this aperture control device that performs super-automatic exposure control, the output of the on-halation taro 7 is at a higher level than the voltage V66 of the non-inverting input terminal of the comparator 67, which is set by the variable resistor 66, and the analog switch 6 is turned on. Therefore, as the output voltage of the operational amplifier 15 increases, the aperture becomes more suitable, and when Vα+' JAVact≧v66, the output of the comparator 67 becomes L” level and the analog switch 68 is turned off. The differential output of the operational amplifier 23 is no longer transmitted to the operational amplifier 26, and the output voltage of the operational amplifier 15 is maintained at a voltage value that matches the voltage V66. Therefore, from then on, the output voltage vBv of the operational amplifier 60! The aperture time is affected only by the change in +8v, and when the voltage VBv/+8v drops to the voltage V66 as shown in Fig. 13, the comparator 12 (see Fig. 7) sets the aperture stop to 'H'.
A level signal is output. Therefore, by performing such aperture control, it is possible to obtain a program characteristic line P having, for example, a straight line portion of 000 and a half lines on the AV axis at a rate of /second as shown in FIG. In addition to the circuit shown in FIG. 12 described above, a circuit for performing such super-automatic exposure control may be configured as shown in FIG. 12. For example, in the electrical circuit shown in FIG. This can also be achieved by configuring a circuit that cuts off signal transmission to the next-stage integrating circuit when the value exceeds this value.

In addition, a case will be described in which a wide open F@I AV is introduced in the aperture control device shown in FIG. 7 above. According to equation (5) above, even if the subject brightness value BV is constant, the aperture F value AVF differs depending on the lens, so if the aperture F value AVF of the basic program characteristics determined in design
If a lens with an open F-number AvF larger than 0 is used, then the number of stops will change depending on the open F-number AVF of the lens, and the aperture value AV will also change.

That is, the above program is also a gonad P. is the lens's open F-number A
When vF is different from the above-mentioned open F value AVo, not only the right straight part shown in FIG. 1 but also the straight part with the slope γ! , also the 15th
As shown in the figure, move parallel to the TV axis, and each open F value A
Program characteristic line P according to VF. 1 #PO21・
Accordingly, aperture control is performed to determine the aperture value AV.

Therefore, if it is desired to perform aperture control with a programmed characteristic such that the linear portion, e2, of the programmed characteristic line Po does not change even if the open F value AV is introduced, the electric circuit shown in FIG. , the correction signal V is connected to the terminal 57.
Apply x. That is, if X is the correction amount when introducing the open F value AV that changes due to lens exchange, then from the above formula (5), AV = Sieve BV + 5V - n + x - AV
, )+AV, ---(17), so this (17
) is equal to the above equation (5), then Yoyo(BV+8V-a+x-AV,)+AV.

Then, it can be obtained from this equation (18). According to the above equation (17), which takes into account the correction amount X shown in equation (19), the program characteristic line P2 as shown in FIG.
When changes, the part corresponding to the straight line Po in the program characteristic line Po in Fig. 1 changes, but the straight part 1□
does not change. Therefore, by applying a voltage Vx;v1(Avo-AvF)γ proportional to the correction amount X to the terminal 57, the aperture control according to the program characteristic line P8 shown in FIG. 16 can be performed.

After aperture control is performed by the aperture control device of the present invention, the movable reflection mirror is raised, the shutter is opened, and the film is exposed to the subject light that has passed through the actual aperture. As a means for determining the shutter speed, for example, TTL direct photometry is performed, and when the integral value obtained by this TTL direct photometry reaches a value that allows the shutter speed corresponding to the aperture value on the above-mentioned Plumgram characteristic line to be obtained, the shutter is activated. Alternatively, a method may be adopted in which the time required for narrowing down the aperture in the aperture control described above is stored and the shutter speed is determined in accordance with this time.

As described above, according to the present invention, the photometric output that has passed through the aperture during aperture operation is determined by the calculated output obtained by calculating and inverting the photometric output so as to satisfy a predetermined program characteristic. Since the aperture control is performed according to the number of steps, there is no need to calculate the subject brightness value at the maximum aperture, unlike conventional methods, and this is useful for cameras that do not have a transmission member for introducing the maximum aperture. Also, it is possible to perform aperture control based on predetermined program characteristics.

[Brief explanation of the drawing]

FIG. 1 is a basic program characteristic diagram determined by program constants in an aperture control device for a programmable camera according to the present invention, and FIG. 2 is an electrical diagram of an aperture control device for a programmable camera according to an embodiment of the present invention. The circuit diagram and FIG. 3 are changes in the output voltage for diaphragm control in the diaphragm control device shown in FIG. 2 above. 4 to 6 are electrical circuit diagrams showing specific circuit configuration examples of the aperture operation voltage generating circuit in the aperture control device shown in FIG. The electrical circuit diagrams of the aperture control device of the program type camera shown in FIGS. 8 to 11 are for explaining the method of correcting errors during actual aperture control in the aperture control device shown in FIGS. 3 and 7 above. Fig. 12 is an electrical circuit diagram of the main part of an example of an aperture 31 control device for super-automatic exposure control.
3 is a diagram of changes in output voltage for aperture control by the aperture control device shown in FIG. 12 above, FIG. 14 is a programm characteristic diagram obtained by the aperture control device shown in FIG. 12 above, and FIG. In the aperture control device shown in Fig. 2, the opening F
FIG. 16 is a program characteristic diagram showing changes in the program characteristic line when the values are different.
FIG. 6 is a program characteristic diagram showing a change in a program characteristic line when a value is introduced. 1... Photographing lens 2... Aperture 3... Light receiving element 4... Op-amp for photometry circuit 12... Comparator (comparison circuit) 18... Aperture control Patent applicant for magnet coil (diaphragm drive means) Agent for Olympus Optical Industry Co., Ltd.
Fujikawa 7th part, ;'132- v) 3 Figure 71 Q He-'' 10- O 11th ward, Tsuta 12th ward, Suji 13th ward Procedures Amendment (spontaneous) Commissioner of the Japan Patent Office Kazuo Wakasugi 1, Indication of the case 1983 Patent Application No. 83682 2
, Title of the invention Programmable camera aperture control device 3
, Relationship with the case of the person making the amendment Patent applicant location 2-46-2 Hatagaya, Shibuya-ku, Tokyo Name (037) Olympus Optical Industry Co., Ltd. 4,
Agent Address: Shimak, 5-52-14 Matsubara, Setagaya-ku, Tokyo (TET, 324-2700) '5, ``Claims'' column and ``Detailed Description of the Invention'' of the specification subject to amendment Column 6, Contents of the amendment (1) "Claims" are provided in the attached sheet. (2) Delete the text after "photometric output" in line 11 of page 6 of the specification and before "calculation output" in line 16 of the same page, and replace it with U.
The aperture stop change output is calculated so that it satisfies predetermined program characteristics. (6) "Including time" stated in the 5th line of page 27 of the same
Change it to "inclusive number of stages". (4) Delete the text after "Photometric output" in line 14 of page 30 and before "calculation output" in line 16 of the same page, and replace it with "Set the aperture change output as specified." ``operated to satisfy the program characteristics of ``. 2- Attachment "2. Claims Determine the aperture value corresponding to the brightness of the subject, measure the amount of light from the subject that passes through the aperture with the determined aperture value, and set the shutter speed corresponding to the aperture value above. In a programmable camera that performs exposure operations, it includes an aperture driving means that gradually narrows down the aperture from the maximum aperture to the minimum aperture, and a light receiving element that receives the subject light flux that has passed through the photographic lens and the aperture. a photometric circuit that emits an output corresponding to the photoelectric change of the light-receiving element; a detection device that detects the amount of aperture by the aperture driving device; an arithmetic circuit that performs calculations to satisfy the following; an output of the arithmetic circuit; A comparison circuit for generating an aperture stop signal for stopping the aperture operation of the aperture driving means when the difference between the two river forces reaches a predetermined value by comparing the outputs, and a programmable camera aperture control device comprising: .”

Claims (1)

[Claims:] A program that determines an aperture value in accordance with the brightness of a subject, measures the amount of light from the subject that passes through the aperture with the determined aperture value, and performs an exposure operation at a shutter speed corresponding to the aperture value. In a type camera, the device includes an aperture driving means that gradually narrows down the aperture from the maximum aperture to the minimum aperture, and a light receiving element that receives the subject light flux that has passed through the photographing lens and the aperture, and the photoelectric change in the light receiving element that occurs as the aperture stops. a photometric circuit that outputs an output corresponding to the photometric circuit; an arithmetic circuit that calculates and inverts the output of this photometric circuit so that it satisfies predetermined program characteristics; An aperture control device for a programmable camera, comprising: a comparison circuit that issues an aperture stop signal for stopping the aperture operation of the aperture driving means when the difference between the two river forces reaches a predetermined value.