JPS5849919A - Exposure controller - Google Patents

Abstract

PURPOSE:To switch automatically the control to the exposure control for strobe photography, by fixing a specific combination between a stop and shutter seconds by the digital signal issued from the strobe. CONSTITUTION:Analog information of the luminance of an object which is corrected by inputs from a film sensitivity setting part RS and an opening F value setting part RF is outputted to an A-D converter ADC. Information of the luminance of the object digitized by the converter ADC is ranked by a decoder DEC and is sent to a stop controlling circuit AC and a shutter controlling circuit SC through a strobe photography setting circuit EG to operate stop setting solenoids beta1 and beta2 and shutter starting solenoids gamma1 and gamma2. Thus, the control is switched automatically to the exposure control for strobe photography.

Description

[Detailed Description of the Invention] The present invention is a programmatic exposure control device, in which when an automatic optical strobe is used, exposure control for strobe photography is automatically performed by attaching the strobe to the camera. The present invention relates to a device that does this.

Automatic exposure control devices that employ an aperture-priority or speed-priority exposure control method are widely used. The structure of this exposure control method is relatively simple, and the combination of aperture and shutter speed can be changed according to the shooting conditions, but if you adjust the aperture and shutter speed settings, the exposure will be automatically set to 0. The result is that the range of light amount values that can be controlled is narrowed. On the other hand, with the program control method, the exposure conditions are determined by a combination of aperture and time, which are programmed in advance according to the brightness of the subject, allowing a wide range of light intensity values. Automatic exposure control is possible.

However, even with this program control, there is a problem that the device for setting the aperture and shutter speed in parallel becomes complicated, and the setting takes time.

In contrast, the present invention #1 first ranks the subject brightness information or the subject lf degree information corrected by other exposure determining factors such as film sensitivity, and then sets the aperture in coarse steps according to the ranks. In addition to selecting the value,
We have invented a programmable electric shutter that sets the shutter speed in parallel with the aperture value selection based on the rank and subject brightness information, thereby solving the above drawbacks. (
On the following page, we proposed a method that simplified the exposure control circuit and improved the accuracy of exposure condition setting by performing the above exposure control using digitalized information. (Special Patent No. A54-163539) This invention adds a circuit to the above-mentioned improved exposure control circuit for automatically switching to exposure control for flash photography when an autoflash flash is attached to the camera. The aim is to obtain an automatic exposure control device.

A detailed explanation will be given below with reference to the drawings.

FIG. 1 is a block circuit diagram showing one embodiment of the exposure control circuit of the present invention. In the figure, PA is a photometric circuit having a light receiving element PD, and EC connected to the photometric circuit PA is an analog calculation circuit. Analog information is outputted as necessary from an A-D converter ADCK having a built-in register. The subject brightness information digitized by the converter ADC is ranked by the decoder DEC, and is sent to the aperture control circuit AC and shutter control circuit SC via the flash photography setting circuit EG.
Operate the aperture setting solenoids β4 and I2 and the starter and rear curtain start solenoids γ5 and γ2 of the shutter.

In the figure, O8C is a built-in oscillation circuit, FD is a frequency dividing circuit, and C
C is a main control circuit, which starts operation in response to release signals S1 and S2, and outputs a film winding completion signal W after shooting.
It is restored by E.

The construction and operation of these circuits, which are operating solenoids for the α mirror, diaphragm, film winding, etc., are the same as those in Tokusho No. 163539/1987, which the present inventor previously filed.

When using an auto-adjustable flash, the flash is attached to the accessory shoe As of the camera;
Shoe As has three contacts, each of which is automatically connected to a corresponding contact on the strobe side. Contact a is connected to a synchro contact XS of the shutter. The contact point S is connected to the strobe photography setting circuit EG to input aperture value designation information from the strobe side. Contact C is connected to film sensitivity setting section R8 and inputs film sensitivity information to the strobe.

FIG. 2 is a detailed diagram of an example of a strobe photography setting circuit.

In this embodiment, the aperture control signals δ4, δ2 from the decoder DEC are input to the aperture control circuit AC via AND gates A1, A2, and OR gate 02, and the shutter speed control signals T0 to T7 are input to the AND gates A3 to A2. A. The signals are then input to the shutter control circuit SC via OR gates 03 and 04.

EF is the input terminal for aperture specification information from the strobe.
In the normal AE shooting mode, no strobe signal is input, and in the strobe shooting mode, for example, when the aperture value is F:&6,
In the case of i'0', F:11, 111 is input.

First, if the input EFIC and strobe signals are not input in AI shooting mode, this terminal EF will be in a floating state, and the transistors T4, T2, T
, are both off. Therefore, inverter 1
5, the output of I2 is %Ol and 1, and the outputs of D flip-flops D1 and D2 are both %01. In this state, Andgate people.

Inverter I, 1. Since the input from A is always %11, the aperture control signal δ is sent directly to the aperture control circuit A.
It is input to C. On the other hand, since the input from the D flip-flop D2 to the OR gate 0□ is ON, the aperture control signal β2 is input as is to the AND gate A2, and the input signal β2 is input to the AND gate A2.

Since the output of is %11, the signal δ2 is directly input to the aperture control circuit AC.

On the other hand, the shutter speed control (No. 1 T0 to T7 passes through AND gates A, ~A, etc., but D flip-flops D1, D
2 outputs are both %OI, and the OR gate 0. The output of is %OI, so the output of the input terminal 15 is 11N, which is the above-mentioned AND gate A, ~A,. Since it is one input of the control signal T. -T, hasonama＼
This is the output of the AND gate. anime) A6, A8
Only the output of is input to the second gate 05.04, but since one input is the output %0# of the OR gate 01, it is the control signal T after all. -T7 is directly input to the shutter control circuit SC. In this manner, when there is no signal input from the terminal EF, the flash photography setting circuit EG inputs the output signal from the decoder DEC as it is to the aperture and shutter control circuit AC%SC.

When the signal %Of corresponding to the terminal EFK% is inputted, for example, F:ss, the transistors T2 and T are turned on, and accordingly, the output of the inverter 12 becomes %ll, and this is turned on at the timing when the clock signal CK is added. The output Q of the read D flip 70 tube D2 is also %11. Therefore, the output of inverter 14 changes to 10'. Meanwhile, inverter I.

The output of is % lI. Therefore, the output δ of the AND gate A, to which the output of the gate A is input, is the signal a.

% g l regardless of the Also, since the output of OR gate 02 is always %lN regardless of how the signal δ2 changes, the output δ'2 of gate A2 is also %lN.
11, and the inputs δ:, δ; to the aperture control circuit AC are F: regardless of the outputs δ4, δ2 of the decoder.
%O1l corresponding to 56%.

Also, ORGATE 0. The output is 111. Inverter I5
The output of is %01, so the AND gate A, ~A
,. All outputs are %oI, or gate 0,04
Therefore, regardless of the output from the decoder DEC, the input to the shutter control circuit SC is %ooooiotoo corresponding to T0 to T7.
', which in the illustrated example is T, + T, = 1.95 + 7.81 = 9.76 m, e
-1/1oose.

So, the height is 14°. This means that the shutter is set in seconds.

For example, when a signal %l l corresponding to F:11 is input to the terminal EF, the transistor T is turned on, and accordingly, the output of the inverter l is %ll, and the clock signal CK causes the D flip 1 flop to be turned on. The output Q of D is %lN,
The output of the inpertae is % g l. For this reason,
Regardless of the aperture control signal δ and δ2 from the decoder DEC, the output δ(, δ; of AND gates A1 and A2 is always %o〃, and the input to the aperture control circuit AC is F:1
It is kept at '001, which corresponds to 1.

On the other hand, as the output of the D flip 7F tube D becomes %ll, the output of the OR gate 01 becomes %II, and the output of the inverter I5 becomes %oI, and the shutter control circuit Input to SC is %0001
0100'IC fixed and signed. . With the release of the shutter (not shown), the application of clock pulses to the D clip-flops D4 and D2 is stopped.
The output Q is held until the photographing operation is completed. This prevents the aperture and shutter control signals from changing even if the aperture and shutter control circuits AC and SC do not have a memory function and the input signal to the terminal EF changes due to the flash force. It is effective for

The above embodiment is an example in which the output signal of the decoder DEC is fixed by the strobe photography setting circuit EG, but the decoder DE
The input signal of C may be fixed, and FIG. 3 shows an embodiment thereof.

When no strobe signal is input to the terminal EF, the outputs of the D flip-flops D4 and D2 are both % as in the first embodiment.
It is ON, the output of OR gate 01 is %Ol, and the output of inverter 5 is %11.

Therefore, AND gates A1 to A6 and OR gate 0
2.0! ! , 04 are all output signals of the A-D converter. - coincides with D5, and in addition, inverter I6
Since the output of is %11, the output of AND gate A7 matches the aperture control signal δ2 of the decoder. In this way, when there is no input from terminal EF, photographing is performed in the normal AE mode.

When the signal %Ol corresponding to the terminal EFKF: 56 is input, the output of the D7 lip 70 knob D2 is %ll, as in the first embodiment, and therefore the output of the OR gate 01 is $1#,
The output of the inverter 15 becomes 10I. For this reason, AND gate A4. ~A, 6 outputs are all %OI, OR gates o2, o5, o4 outputs are 'I', and decoder D
ECsc is F: 5.6/. . A signal turtle 100110' corresponding to exposure information for seconds is input. At this time, the output of the impermeter is 11, and the aperture information δ2 becomes the output of the AND gate A17.

When the signal %11 corresponding to EFK, F: 11 is input, the output of OR gate o1 becomes 11' as above.
, the output of inverter 15 becomes %g/, and decoder DE
The input to C becomes a signal '100110 corresponding to the centering F: 5.6/10 seconds. However, in this case, the output of inverter I6 becomes % ON, and AND gate A7
By setting the output to 0', the aperture control signal becomes F:
Convert to lIK.

As described above, with the circuit including a small number of D7 lip-flops, it is possible to fix the aperture control signal based on the strobe information signal, and at the same time fix the shutter control signal to a time generally suitable for strobe photography. Although a knee control circuit with no function is used, it is possible to have a signal holding function using a strobe photography setting circuit in the strobe photography mode.

It goes without saying that the design of the above-mentioned circuit can be changed at any time without being limited to the embodiment, depending on what kind of signals are made to correspond to what kind of exposure conditions.

[Brief Description of the Drawings] Fig. 1 is a block circuit diagram of an embodiment of the exposure control X1fc according to the present invention, Fig. 2 is a detailed diagram of the strobe photography setting circuit, and Fig. 3 is a detailed diagram of the strobe photography setting circuit. FIG. 6 is a detailed view of another embodiment. PA: Photometric circuit EC = Analog calculation circuit R8: Film sensitivity setting section RF: Open F value setting section ADC: A-D
Converter DEC: Decoder EG: Strobe shooting setting circuit AC: Aperture control circuit SC: Shutter control circuit O20: Oscillator circuit FD bifurcation circuit wI CC: Main control circuit α: Mirror force operation solenoid β: Aperture setting solenoid r: Shutter curtain start Solenoid AS: Accessory Shoe Patent - Person Roku Konishi Photo Industry Aji Shiki Company Investor Agent
Patent attorney Fumi Sato (and 1 other person)

Claims (1)

[Claims] In a programmable exposure control circuit that uses digital exposure information including subject brightness information to select a predetermined combination of aperture value and shutter speed using a decoding circuit, a digital signal emitted from the strobe is used to select a specific combination of aperture and shutter speed. Exposure control fXl device characterized by fixed