JP2855591B2 - Camera control device and camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus of a zoom lens.
Control of camera that performs A / D conversion operation of signal corresponding to distance
The present invention relates to improvement of a control device and a camera .

[0002]

2. Description of the Related Art In a lens shutter type camera, when the focal length changes, the FNo. In general, the amount of lens extension at the time of focusing is changed. In order to perform the correction and the lens extension amount correction, a focal length detecting unit is required.

The most common type of the focal length detecting means is that a brush moves on a gray code code pattern in conjunction with the focal length movement.
In addition, there is also a method of detecting the focal length using a variable resistor whose output varies in conjunction with the movement of the focal length, and this method is more effective from the viewpoint of high-precision detection.

FIG. 6 shows an example of the configuration of a focal length detecting means using a variable resistor capable of detecting the focal length of a zoom lens with higher precision.

[0005] In FIG. 6, both ends of the total resistance are connected to a constant voltage Vc (= 2.5 V) and GND, the movable contact moves in conjunction with zooming, and the movable contact moves to the Vc side during the TELE zoom. The movable contact piece is GN during WIDE zoom
The variable resistor that moves to the D side 22 is the variable resistor 21
_{Is an} A / D converter for A / D converting the potential V _OUT of the movable contact piece.

[0006] The digital output from the A / D converter 22 is input to a sequence controller that controls various circuits of the camera, and is then divided into a plurality of zones so that arithmetic processing is easy.

FIG. 7 shows an example of the relationship between V _OUT and the corresponding focal length when the division is made into 13 zones.

In this example, the focal length of the camera is "35 to
105 mm ", and TELE
Numbers 1 to 1 called zoom position (ZP) in order from the end
13 is attached.

[0009]

However, in the above-mentioned conventional example, the linearity of the A / D converter is deteriorated when the power supply voltage drops. Therefore, if the focal length is detected during flash charging, the detection can be performed correctly. There was a problem that there is no.

(Object of the Invention) The present invention has been made in view of the above circumstances, and guarantees the accuracy of an A / D conversion operation in determining the focal length of a zoom lens.
Camera that can always correctly determine the focal length of
It is intended to provide a control device and a camera.

[0011]

To achieve the above object, the present invention according to claim 1 provides a zoom lens having a focal length.
The variable resistor whose resistance value changes with the separation change
Signal output means for outputting a signal corresponding to the focal length of the zoom lens, and A / D conversion of a signal from the signal output means
A / D converter and the output of the A / D converter
Determination means for determining the focal length of the serial zoom lens, the
According to another aspect of the present invention, there is provided a camera control device including control means for preventing the A / D converter from performing the A / D conversion operation and the strobe charging operation at the same time. Claim 2
The described invention can be used as the focal length of the zoom lens changes.
The resistance of the zoom lens is changed by a variable resistor whose resistance value changes.
Signal output means for outputting a signal corresponding to the focal length;
A / D conversion for A / D converting a signal from the signal output means
And a zoom lens according to an output of the A / D converter
Determination means for determining the focal length of
Detects the state of the power supply voltage after the start and before the end of the flash charging operation.
Voltage detecting means, and the voltage detected by the voltage detecting means.
If the state of the power supply voltage does not reach the predetermined level, the A /
Prevent the A / D conversion operation of the D converter from being performed
Control device for camera having control means for
It is. The present invention according to claim 3 is a zoom lens.
Resistor whose resistance value changes with the focal length of the lens
Generates a signal corresponding to the focal length of the zoom lens.
Signal output means for outputting the signal from the signal output means.
A / D converter for A / D conversion, and output of the A / D converter
Determining means for determining the focal length of the zoom lens by force
Stage, the A / D conversion operation of the A / D converter,
Control means to prevent simultaneous charging operations
The camera has a step. Claim 4
The described invention can be used as the focal length of the zoom lens changes.
The resistance of the zoom lens is changed by a variable resistor whose resistance value changes.
Signal output means for outputting a signal corresponding to the focal length;
A / D conversion for A / D converting a signal from the signal output means
And a zoom lens according to an output of the A / D converter
Determination means for determining the focal length of
Detects the state of the power supply voltage after the start and before the end of the flash charging operation.
Voltage detecting means, and the voltage detected by the voltage detecting means.
If the state of the power supply voltage does not reach the predetermined level, the A /
Prevent the A / D conversion operation of the D converter from being performed
And a control means for the camera.

[0012]

[0013]

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 is a block diagram showing a main configuration of a zoom camera according to a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a sequence controller for controlling the sequence of the entire camera, 2 denotes a flash circuit used for flash photography, 3 denotes a distance measuring circuit for measuring a subject distance, and 4 denotes photometry for measuring a subject brightness. circuit,
Reference numeral 5 denotes a lens driving circuit that performs focusing by inputting a lens driving amount calculated based on the distance information measured by the distance measuring circuit 3, 6 denotes a shutter, and 7 denotes a shutter driving circuit that drives the shutter 6. , 8 are photographing lenses.

Reference numeral 9 denotes a focal length detection circuit using a variable resistor for detecting the focal length of the photographing lens 8.
This configuration has the same configuration as that of FIG. The digital output from the A / D converter in the circuit 9 is input to the sequence controller 1 and then divided into a plurality of zones as shown in FIG.

Reference numeral 10 denotes a zoom motor for performing zooming, 11 denotes a zoom motor drive circuit for driving the zoom motor 10, 12 denotes a feed circuit for feeding a film, 15 denotes a release switch, and 16 denotes a long focal length. A TELE switch for zooming to the side, 17 is a WIDE switch for zooming to the short focal length side, and 18 is a battery serving as a power supply of the camera.

The operation of the zoom camera having the above configuration will be described with reference to the flowchart of the sequence controller 1 shown in FIG. In the initial state, it is assumed that the flash is not charged, for example, immediately after the release of the flash emission.

First, in step 101, a strobe charging start signal is output to the strobe circuit 2 to start strobe charging. Then, in the next step 102, it is determined whether or not a charge completion signal has been input from the flash circuit 2. As a result, if the charging completion signal has been input, the operation is terminated.
03, where the focal length of the zoom lens is detected,
That is, it is determined whether or not it is necessary to detect the zoom position (ZP). If it is not necessary to perform the detection, it is determined whether the strobe charging is completed or not Step 1
Return to 02.

On the other hand, if it is necessary to detect the zoom position (ZP) before the completion of the flash charging, the process proceeds from step 103 to step 104, in which a flash charging stop signal is output to the flash circuit 2 to stop the flash charging. . Then, in step 105, the control waits for a guarantee time T for the power supply voltage to return to a level at which the linearity of the A / D converter in the focal length detection circuit 9 can be guaranteed.
When the guaranteed time T has elapsed, the process proceeds to step 106, in which the zoom position is read by operating the focal length detection circuit 9 (A / D converter), that is, A / D conversion is performed, and the process returns to step 101 again to return to the flash. Start charging.

(Second Embodiment) In the first embodiment, the strobe charging is always stopped when the zoom position is detected. However, when the zoom position detection is not urgent, the strobe charging is performed after the completion of the strobe charging. You may do it. The operation of the main part of the zoom camera according to the second embodiment of the present invention will be described with reference to the flowchart of the sequence controller 1 shown in FIG.

The circuit configuration of the zoom camera for performing the second embodiment is the same as that shown in FIG.

First, in step 201, a strobe charging start signal is output to the strobe circuit 2 to start strobe charging. Then, in the next step 202, it is determined whether or not a charging completion signal has been input from the flash circuit 2. As a result, if the charging completion signal has been input, the operation is terminated.
03, where the focal length of the zoom lens is detected,
That is, it is determined whether or not it is necessary to detect the zoom position (ZP). If it is not necessary to perform the detection, it is determined whether or not the flash charging is completed.
Return to 02.

On the other hand, if it is necessary to detect the zoom position (ZP) before the completion of the flash charging, the process proceeds from step 203 to step 204, where it waits for the input of a charging completion signal from the flash circuit 2. Thereafter, when the charge completion signal is input, the process proceeds to step 205, where the focal length detection circuit 9 (A / D converter) is operated to read the zoom position, that is, A / D conversion is performed, and the operation ends.

(Third Embodiment) FIG. 4 is a block diagram showing a main part of a zoom camera according to a third embodiment of the present invention. The same parts as those in FIG. 1 are denoted by the same reference numerals.

In FIG. 4, reference numeral 19 denotes a power supply voltage detection circuit such as a comparator that detects whether the power supply voltage of the camera has returned to a level that guarantees the detection accuracy of the A / D converter in the focal length detection circuit 9 . It is.

[0028]

In the third embodiment, as in the second embodiment, when the flash is being charged at the time of zoom position detection, the battery 1 does not necessarily have to wait until the charging is completed.
If the power supply voltage of No. 8 has returned to a level that guarantees the A / D conversion accuracy, there is no problem even if zoom position detection is performed. Therefore, this determination is made based on the output of the power supply voltage detection circuit 19, and The operation of is advanced.

FIG. 5 is a flowchart of the sequence controller 1 for realizing this, and will be described below.

First, in step 301, a strobe charging start signal is output to the strobe circuit 2 to start strobe charging. Then, in the next step 302, it is determined whether or not a charge completion signal has been input from the flash circuit 2. As a result, if the charging completion signal has been input, the operation is terminated.
03, where the focal length of the zoom lens is detected,
That is, it is determined whether or not it is necessary to detect the zoom position (ZP). If it is not necessary to perform the detection, it is determined whether or not the flash charging is completed.
Return to 02.

On the other hand, if it is necessary to detect the zoom position (ZP) before the strobe charging is completed, the process proceeds from step 303 to step 304, where the output from the power supply voltage detection circuit 19 is read, and the next step is performed. 30
In step 5, based on the read information (power supply voltage state), it is checked whether or not the power supply voltage has returned to the level (guaranteed accuracy) of the A / D converter in the focal length detection circuit 9 (linearity). If the power supply voltage has not returned to the accuracy guarantee level of the A / D converter, the process returns to step 304 and the same loop is repeated. Then, when the power supply voltage returns to the accuracy guarantee level of the A / D converter, step 30 is executed.
The program proceeds to step 6, where the focal length detecting circuit 9 (A / D converter) is operated to read the zoom position, that is, A / D conversion is performed. Then, in the next step 307, the process waits for a charge completion signal to be input from the strobe circuit 2, and ends the operation when the charge completion signal is input. FIG. 5 is a flow chart of the sequence controller 1 for realizing this, and will be described below.

According to each of the above embodiments, when the focal length is detected, strobe charging is always prohibited (first embodiment), or until the charging is completed (second embodiment). Voltage is A / D converter accuracy (linearity)
Since the return to the guaranteed level is waited (third embodiment), the linearity of the A / D converter in the focal length detection circuit 9 is guaranteed, and the focal length detection can always be performed correctly.

(Correspondence between Invention and Embodiment) In the above embodiment, the variable resistor 21 to which the constant voltage Vc is
In the signal output means of the present invention, the A / D converter 22 includes the A / D converter of the present invention.
The step 106 shown in FIG. 2 and the step shown in FIG.
205, a sequence code for executing step 306 in FIG.
The functional part of the controller 1 corresponds to the determination means of the present invention,
Steps 102 to 105, steps 202 to 20 in FIG.
The function part of the sequence controller 1 that executes
The control means of the present invention according to claims 1 and 3 includes a power supply voltage detection.
The output circuit 19 is connected to the voltage detecting means according to claims 2 and 4,
A sequence code for executing steps 302 to 305 in FIG.
The functional part of the controller 1 according to claim 2 or claim 4
These correspond to the light control means, respectively.

As described above, claims 1 to 4
In accordance with the present invention according to ensure the accuracy of the A / D conversion operation in the determination of the focal length of the zoom lens, Zumuren
Camera that can always correctly determine the focal length of the camera
Of the present invention can be provided.

[0035]

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a main configuration of a zoom camera according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of a portion of the zoom camera of FIG. 1 according to the present invention.

FIG. 3 is a flowchart illustrating an operation of a main part of a zoom camera according to a second embodiment of the present invention.

FIG. 4 is a block diagram illustrating a main configuration of a zoom camera according to a third embodiment of the present invention.

FIG. 5 is a flowchart illustrating an operation of the zoom camera of FIG. 4;

FIG. 6 is a circuit diagram showing a configuration of a general focal length detecting means.

FIG. 7 is a diagram showing the relationship between the output level of the focal length detecting means of FIG. 6 and the corresponding focal length.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Sequence controller 2 Strobe circuit 8 Photographing lens 9 Focal length detection circuit consisting of variable resistor and A / D converter 10 Zoom motor 11 Zoom motor drive circuit 19 Power supply voltage detection circuit 21 Variable resistor 22 A / D converter

Claims (4)

(57) [Claims] 1. The resistance of a zoom lens varies with the focal length.
The focus of the zoom lens is changed by a variable resistor whose resistance value changes.
And signal output means for outputting a signal corresponding to point distance, the
A / D converter for A / D converting a signal from signal output means
And the output of the A / D converter,
Determining means for determining the focal length, prior to said A / D converter
A control device for a camera, comprising: control means for preventing the A / D conversion operation and the strobe charging operation from being performed simultaneously. 2. The resistance is changed according to a change in the focal length of the zoom lens.
The focus of the zoom lens is changed by a variable resistor whose resistance value changes.
Signal output means for outputting a signal corresponding to the point distance;
A / D converter for A / D converting a signal from signal output means
And the output of the A / D converter,
Judgment means for judging focal length and start of flash charging operation
Detects power supply voltage state before end of post-strobe charging operation
Voltage detecting means, and a voltage detected by the voltage detecting means.
If the state of the source voltage does not reach the predetermined level, the A / D
To prevent the A / D conversion operation of the converter from being performed.
Control means for controlling a camera
apparatus. 3. The resistance is changed according to a change in the focal length of the zoom lens.
The focus of the zoom lens is changed by a variable resistor whose resistance value changes.
Signal output means for outputting a signal corresponding to the point distance;
A / D converter for A / D converting a signal from signal output means
And the output of the A / D converter,
Determining means for determining a focal length;
Do not perform A / D conversion operation and strobe charging operation at the same time.
Control means for controlling
Camera . 4. A resistance change according to a change in the focal length of the zoom lens.
The focus of the zoom lens is changed by a variable resistor whose resistance value changes.
Signal output means for outputting a signal corresponding to the point distance;
A / D converter for A / D converting a signal from signal output means
And the output of the A / D converter,
Judgment means for judging focal length and start of flash charging operation
Detects power supply voltage state before end of post-strobe charging operation
Voltage detecting means, and a voltage detected by the voltage detecting means.
If the state of the source voltage does not reach the predetermined level, the A / D
To prevent the A / D conversion operation of the converter from being performed.
And a control unit for controlling the camera.