JP2906336B2 - Electric zoom camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric zoom camera, and more particularly to an electric zoom camera in which the focal length can be changed stepwise.

[0002]

2. Description of the Related Art A conventional electric zoom camera has a zoom switch, and zooming of a photographing lens is continuously performed only while an operation signal is input from the switch. Then, the operation of the zoom switch is stopped to perform desired zooming (this zooming is hereinafter referred to as a manual electric zoom). For this reason, for example, when changing the focal length of 30 mm to 50 mm, there is a problem that it is necessary to continuously operate the zoom switch, and the usability is poor. The focal length can be changed stepwise by the zoom command, or for example, 30mm
The focal length can be changed in steps from 45 mm to 60 mm (hereinafter, this zoom method is referred to as step zoom), and photographing is performed each time zooming to each focal length is completed (hereinafter, this zoom method is referred to as step zoom). We proposed an electric zoom camera (the shooting method is called zoom continuous shooting). (Zooming that is automatically performed to a preset focal length, such as the above step zoom and zoom continuous shooting, is hereinafter called automatic electric zoom.) .

[0003]

By the way, in the automatic electric zoom camera, the opening F value of the photographing lens corresponding to the focal length at each step position is stored in a table in advance, and
Release F of step position set by step zooming
Since the exposure value can be calculated by reading the value, an appropriate exposure value can be obtained. However, in an automatic electric zoom camera capable of manual zooming, the photographing lens can be set to an arbitrary position by manual zooming. Therefore, the photographing lens is often set to a position other than the step position of the automatic electric zoom. At such a set position between the step positions, the set position itself cannot be detected unless a position detecting device that continuously detects the zoom position is provided. An open F value corresponding to the focal length cannot be obtained.
Therefore, the exposure calculation is performed based on the open F value corresponding to the focal length of the step position near the set position, and an appropriate exposure value for an arbitrary manual zooming position cannot be obtained. Of course, if a device for continuously detecting the zoom position is provided, the focal length and the open F value for the intermediate setting position as described above can be obtained, but depending on the type of camera from the viewpoint of cost and installation space, There is a case where it is desired to omit such a zoom position detecting device.

An object of the present invention is to provide an electric zoom camera that performs optimal exposure control based on an open F-number with respect to a focal length of a set position even when manual zooming is performed at a position other than a step position of an automatic electric zoom. It is in.

[0005]

The present invention will be described with reference to FIG. 1. The present invention comprises a position detecting means 101 for outputting position signals at a plurality of predetermined step positions a1 to an; Zoom drive means for setting the taking lens to the step positions a1 to an by a position signal output from the position detecting means 101 in response to the step zoom command and setting the taking lens to an arbitrary position in response to the manual zoom command 102, wherein the open F-number of the taking lens corresponding to the focal length of the step positions a1 to an and two adjacent step positions a1
Opening F of the photographing lens corresponding to the focal length between -an
F-value storage means 102 for storing values and position detection means 1
An exposure control means 104 for reading out an open F value corresponding to the set position of the photographing lens from the F value storage means 103 based on the position signal output from 01 to perform exposure control, thereby achieving the above object. . The position detecting means 101 of the electric zoom camera according to the second aspect has a conductive pattern corresponding to the plurality of step positions a1 to an and a brush that slides on the conductive pattern in conjunction with zooming of the photographing lens. The invention according to claim 3 is a position detecting means for outputting position signals at a plurality of predetermined positions a1 to an.
1 and a zoom drive unit 102 for setting a photographing lens at an arbitrary position including the predetermined positions a1 to an, wherein the opening F of the photographing lens corresponding to the focal length of the predetermined position a1 to an F-number storage means 102 for storing a value and an open F-number of the photographing lens corresponding to the focal length of the intermediate position between two adjacent predetermined positions a1 to an; When the signal is output, the open F value corresponding to the predetermined position is read out from the F value storage means 103 to perform exposure control, and when the position detection means 101 outputs the intermediate position signal, the F value is output. An exposure control unit 104 for reading out the open F value corresponding to the intermediate position from the value storage unit 103 and performing exposure control is provided, thereby achieving the above object. The position detecting means 101 of the electric zoom camera according to the fourth aspect has a conductive pattern corresponding to the plurality of predetermined positions a1 to an and a brush that slides on the conductive pattern in conjunction with zooming of the photographing lens.

[0006]

FIG. 2 is a sectional view showing a zoom mechanism of a photographing lens in an electric zoom camera. A front lens 1 and a rear lens 2 constitute a zoom lens. 3
Is a front lens holding cylinder, 3a is a focusing helicoid engraved on the outer periphery of the holding cylinder 3, 4 is a focusing pin implanted in the holding cylinder 3, 5 is a shutter focusing driving device, 5a is a shutter focusing drive. The helicoid is fixed to the inner periphery of the focusing drive device 5 and meshes with the helicoid 3a for focusing. 6 is a shutter
The focusing lever is driven by a focusing device 5 and moves the front lens group 1 via the engaged focusing pin 4 to perform focusing.
Each of these elements constitutes a focusing mechanism. 7
Is a shutter blade.

Reference numeral 8 denotes a rear group lens holding cylinder, 8a denotes a pin implanted in the holding cylinder 8, 9 denotes a guide cylinder of the rear group lens holding cylinder 8, and a pin 8a is inserted into a rectilinear groove 9a. 8a can travel straight in the optical axis direction. Reference numeral 9b denotes a helicoid engraved on the guide cylinder 9, reference numeral 10 denotes a cam ring rotatably provided on the guide cylinder 9, and a pin 8 around the cam ring.
The cam groove which engages with a is provided. The pin 10a implanted in the cam ring 10 is inserted and engaged with the cam groove 11a of the rectilinear guide plate 11 fixed to the camera 13 as shown in FIG. The engagement of the side portion 11b of the straight guide plate 11 with the projection 9c of the guide cylinder 9 prevents the rotation of the guide cylinder 9.

Reference numeral 12 denotes an intermediate helicoid, and a camera 13
A helicoid portion 12b meshing with the helicoid 13a of
Helicoid 12 meshing with helicoid 9b of guide cylinder 9
a and a gear portion 12c that meshes with a transmission gear 14 that transmits a driving force from an electric driving portion (not shown). Then, an encoder board 15 for position detection is fixed to a part of the intermediate helicoid 12, and this board 15
The encoder brush 16 slides on the conductive pattern.

The helicoid 13a of the camera 13, the respective helicoids 12a and 12b of the intermediate helicoid 12, and the helicoid 9b of the guide cylinder 9 constitute a double helicoid, and the rotation of the guide cylinder 9 by the linear guide plate 11 is prevented. Zooming is performed by moving the lens groups 1 and 2 by the rotational force from the electric drive unit.

FIG. 4 is an exploded view of the encoder substrate 15, in which a switching portion of the conductive pattern 15a, in other words, a pattern switching position at which a position signal obtained from the brush 16 changes is represented by a1, a2,. I have. When the focal lengths of the photographing lenses corresponding to the switching positions are f1, f2,.

(Equation 1) The switching positions a1 to a9 are determined so that the ratio between two adjacent focal lengths is substantially constant. Since the photographing magnification is substantially inversely proportional to the focal length, each switching position a1 to
The change of the photographing magnification at two adjacent positions of a9 becomes equal at any position.

For example, when the photographing lens is a 35 mm to 70 mm zoom lens and the distance between the lenses is divided into nine as described above,
The focal lengths for the switching positions a1 to a9 can be determined as shown in the following table.

[Table 1]

FIG. 5 is a block diagram showing the overall configuration of the control device. The arithmetic circuit 31 receives the photometric value of the subject from the photometric circuit 32, the film sensitivity from the film sensitivity detection circuit 33, and the above-described position signal from the encoder 34. From the zooming command unit 35, a zoom-up command and a zoom-down command in the case of manual electric zoom, a zoom command in the case of automatic electric zoom, and the number of focal lengths that the lens can take in that case, that is, zoom-up or zoom-down. The number of steps to be performed and a zoom continuous shooting command for performing shooting by zoom continuous shooting are input. Arithmetic circuit 31
Drives the zoom motor 37 via the motor drive circuit 36 based on the zooming signal from the zooming command unit 35. On the other hand, the exposure value is calculated based on the photometric value, the film sensitivity, and the open F value of the photographing lens read out according to the position signal from the encoder 34, and the shutter 39 and the aperture 40 are drive-controlled via the aperture / shutter control circuit 38. .

The open F value is determined as follows.
In the case of automatic electric zooming and zoom continuous shooting, when the zooming position commanded by the camera is detected by the position signal of the encoder 34, the taking lens is stopped, so that the focal length corresponding to the position signal is released. Values can be used. Therefore, a correspondence table between the position signal and the open F value may be provided in the arithmetic circuit 31, and the open F value may be obtained from the position signal. On the other hand, in the case of manual electric zooming, the focal length of the photographing lens is not controlled by the position signal from the encoder 34, but rather, the signal of the zoom-up command or the zoom-down command is output or disappeared by the operator, and the photographing lens is moved. Since the focal length is controlled, there is a high possibility that the photographing lens is controlled at an arbitrary position between the two switching positions. So, encoder 3
4, not the open F-number corresponding to the position signal obtained from
An exposure value is calculated based on an open F value corresponding to an intermediate focal length between two adjacent position signals. Therefore, the arithmetic circuit 3
1, a correspondence table between the position signal and the open F value corresponding to the intermediate focal length between the position signals is provided, and the open F value is obtained in the same manner as described above. And automatic electric zooming,
The two tables are switched and used by manual electric zooming.

In the above arrangement, the front lens group 1 and the rear lens group 2 function as photographing lenses, the encoder 34 calculates position detecting means, the arithmetic circuit 31, the motor driving circuit 36 and the zoom motor 37 calculate zoom driving means. The circuit 31 constitutes an F value storage unit and an exposure control unit.

The operation of the camera having such a configuration will be described in the case where the zooming instruction section 35 issues an instruction for, for example, continuous zooming. When the release button is operated by instructing the zoom continuous shooting, the front lens group 1 and the rear lens group 2 move the zoom motor 3
7 at different speeds. And, for example, 3
When the switching position a1 of 5 mm is detected by the position signal from the encoder 34, the motor 37 stops, and the focal length of the photographing lens is set to 35 mm. Then, the front group lens 1
Is driven for automatic focusing. Then, an open F value is obtained from a position signal indicating that the focal length is 35 mm,
A shutter speed and an aperture value are calculated in accordance with a photometric value, a film sensitivity, and the like, and an aperture 39 and a shutter 40 are drive-controlled by a control circuit 38 to perform photographing. The film is then wound up, after which the photographic lens is for example 49.5
The focal length is set to mm, shooting is performed as described above,
Further, the photographing lens is set to a focal length of, for example, 70 mm, and photographing is performed simultaneously. The degree of change in the photographing magnification of the three photographs obtained by such zoom continuous shooting is equally easy to see.

On the other hand, when a command to zoom up by one step is issued from the zooming command unit 35, the front and rear group lenses 1 and 2 are driven by the zoom motor 37, and the focal length becomes longer by one step than at present. For example, as shown in Table 1, the value is changed from 35 to 38.7 mm. By operating the release button, the open F-number corresponding to the position signal of 38.7 mm is looked up from the table, and the exposure value is determined in the same manner as described above. Is decided and shooting is performed.

In the case of manual electric zooming, the focal length of the photographing lens can be set to an arbitrary value by a zoom-up command or a zoom-down command from the zooming command unit 35. At this time, even if the position signal obtained from the encoder 34 is, for example, the switching position a4, the photographing lens is not necessarily at the switching position a4 and may be at an arbitrary position between a4 and a5. Then, the open F-number corresponding to the intermediate focal length between the switching positions a4 and a5 is obtained from the above-mentioned table. As a result, the positions a4 to a5
Since the exposure value is calculated based on the open F value of the average focal length, the accuracy of the exposure amount is improved.

FIG. 6 is a diagram in which the switching positions a1 to a9 are shifted by a fixed amount 1 with respect to the encoder pattern shown in FIG. That is, when the motor 37 is driven and stopped in accordance with the zooming signal from the zooming instruction unit 35, when zooming from the wide direction to the telescopic direction, when zooming from the telephoto direction to the wide direction, for example, one time from the wide direction to the telephoto direction. The motor 37 is stopped by detecting a desired switching position by moving in the direction, thereby improving the accuracy of setting the focal length due to backlash or the like of the photographing lens drive system. This technique is disclosed, for example, in Japanese Patent Application No. 61-291950. In this case, since the moving direction of the photographing lens at the time of stop is always one direction, the moving amount of the photographing lens due to inertia after the motor stop command is estimated in advance, and the switching position is shifted by that amount, that is, by l. As a result, errors due to inertia can be prevented, and control with even higher accuracy can be performed.

[0019]

[0020]

According to the first aspect of the present invention, step zooming of the photographing lens is performed while detecting the step position by the position detecting means for outputting a position signal at a plurality of predetermined step positions, and the position of the photographing lens is set at an arbitrary position. An electric zoom camera that performs manual zooming to set a photographing lens. The open F value of the photographing lens corresponding to the focal length at the step position and the open F value of the photographing lens corresponding to the intermediate focal length between two adjacent step positions. And remember
Based on the position signal output from the position detection means, the exposure control is performed by reading the open F value corresponding to the set position of the taking lens, so that a device for continuously detecting the zoom position is not required. Even when manual zooming is performed at a position other than the step position, the optimum exposure value can be calculated based on the open F value for the focal length at the set position, and the exposure control accuracy can be improved. According to the second aspect of the present invention, the position detecting means is constituted by the conductive pattern corresponding to the plurality of step positions and the brush sliding on the conductive pattern in conjunction with the zooming of the photographing lens. An inexpensive position detection device can reduce the cost and size of the electric zoom camera. According to the third aspect of the present invention, there is provided position detecting means for outputting a position signal at a plurality of predetermined positions, and the opening of the photographing lens corresponding to the focal lengths of the plurality of predetermined positions is provided.
In the case of manual zooming in which the value and the open F value of the taking lens corresponding to the focal length of the intermediate position between two adjacent predetermined positions are stored, and the taking lens is set at an arbitrary position including a plurality of predetermined positions, When the position signal of the predetermined position is output from the position detecting means, the opening F value corresponding to the predetermined position is read out and exposure control is performed. When the position signal of the intermediate position is output from the position detecting means, Since the exposure control is performed by reading the open F-number corresponding to the intermediate position, even if the electric zoom camera does not have the step zoom mode, a device for continuously detecting the zoom position is not installed, and the position other than the predetermined position is set. Even when manual zooming is performed at an intermediate position, the optimal exposure value can be calculated based on the open F value for the focal length at that intermediate position, allowing fine-grained exposure control It made. In addition, the open F value corresponding to the zoom position is continuously stored, the zoom position is continuously detected, and the open F value corresponding to the zoom position is read out to perform the exposure control. And the position detection device can be simplified, and the cost can be reduced. Furthermore, according to the invention of claim 4, since the position detecting means is constituted by the conductive pattern corresponding to the plurality of predetermined positions and the brush sliding on the conductive pattern in conjunction with the zooming of the taking lens, the position detecting means is simple. An inexpensive position detecting device can reduce the cost and size of the electric zoom camera.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims.

FIG. 2 is a sectional view of a zooming drive system according to one embodiment.

FIG. 3 is a sectional view taken along the line AA of FIG. 2;

FIG. 4 is a development view of a printed circuit board according to one embodiment.

FIG. 5 is a configuration diagram of an entire control device according to an embodiment.

FIG. 6 is a development view showing another example of a printed circuit board.

[Explanation of symbols]

 Reference Signs List 1 front group lens 2 rear group lens 15 printed circuit board 15a conductive pattern 16 brush 31 arithmetic circuit 34 encoder 35 zooming command unit 37 zoom motor 101 position detection unit 102 zoom drive unit 103 F value storage unit 104 exposure control unit

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Toshiyuki Nakamura 1-6-3 Nishioi, Shinagawa-ku, Tokyo Nihon Kogaku Kogyo Co., Ltd. Oi Works (56) References JP-A-62-265632 (JP, A) (Japanese) Sho58-87027 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G02B 7/08-7/10

Claims (4)

(57) [Claims] 1. A position detecting means for outputting a position signal at a plurality of predetermined step positions, and a photographing lens is set to the step position by a position signal output from the position detecting means in response to a step zoom command. And a zoom drive unit for setting the photographing lens to an arbitrary position in response to a manual zoom command, comprising: an open F value of the photographing lens corresponding to a focal length at the step position; An F-number storage unit for storing an open F-number of the taking lens corresponding to an intermediate focal length between two adjacent step positions; and a position signal output from the position detection unit,
An electric zoom camera comprising: an exposure control unit that reads an open F value corresponding to a set position of the photographing lens from the F value storage unit and performs exposure control. 2. The electric zoom camera according to claim 1,
And the position detecting means corresponds to the plurality of step positions.
Linked to the conductive pattern and zooming of the taking lens
And a brush that slides on the conductive pattern . 3. A position signal at a plurality of predetermined positions.
Position detecting means for outputting, and setting the photographing lens at an arbitrary position including the predetermined position
An electric zoom camera provided with a zoom driving unit, wherein the opening of the taking lens corresponding to the focal length at the predetermined position is provided.
The release F value and the focus between the two adjacent predetermined positions
Stores the opening F value of the taking lens corresponding to the point distance
And a position signal of the predetermined position is output from the position detecting means.
When the F value is stored,
The exposure control is performed by reading the open F value
The position signal of the intermediate position is output from the position detecting means.
At the time, the F-number storage means opens the memory corresponding to the intermediate position.
Exposure control means for reading out the release F value and controlling the exposure.
Power zoom camera, wherein the obtaining. 4. The electric zoom camera according to claim 3,
And The position detecting means is configured to determine a position corresponding to the plurality of predetermined positions.
In conjunction with the power pattern and zooming of the taking lens
Having a brush that slides on the conductive pattern.
Characterized electric zoom camera.