JPH08254647A - Electric zoom camera - Google Patents

Abstract

(57) Abstract: To improve exposure control accuracy in step zooming. SOLUTION: In step zooming of an electric zoom camera, an opening F value of an average focal length in each step interval is set, and exposure control is performed based on the opening F value corresponding to the step interval at which a photographing lens is stopped during manual zooming. Do.

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 a focal length that can be changed stepwise.

[0002]

2. Description of the Related Art A conventional electric zoom camera has a zoom switch, and zooming of a taking lens is continuously performed only while an operation signal is input from the switch, and a necessary photographing range is confirmed by a viewfinder or the like. Then, the operation of the zoom switch is stopped to perform desired zooming (this zooming is hereinafter referred to as manual electric zoom). Therefore, for example, when changing the focal length of 30 mm to 50 mm, there is a problem that the zoom switch needs to be operated continuously and the usability is poor. For example, the applicant has previously described 30 mm → 45 mm → 60 mm. You can change the focal length step by step by zoom command, or for example, 30mm
→ The focal length can be changed stepwise like 45mm → 60mm (hereinafter this zoom method is called step zoom), and shooting is performed every time zooming to each focal length is completed (hereinafter, this We proposed an electric zoom camera (the shooting method is called zoom continuous shooting) (the above-mentioned step zoom, zoom continuous shooting, and other automatic zooming toward a preset focal length is called automatic electric zoom). .

[0003]

However, when the focal length set by the automatic electric zoom is changed by the arithmetic progression, the degree of change in the screen differs between the short focus side and the long focus side, which makes it difficult to see a photograph that is difficult to see. Become.

It is an object of the present invention to provide an electric zoom camera capable of obtaining a photograph in which the degree of change in the screen is substantially the same regardless of the focal length.

[0005]

To explain with reference to FIGS. 1 (a) to 1 (c), which are diagrams corresponding to claims, an electric zoom camera according to the present invention includes a photographing lens 101 having a zooming function and a photographing lens 101. A detection unit 102 for detecting the focal length, a drive unit 103 for zooming the photographing lens 101, and a command unit 104 for instructing zooming are provided. In the electric zoom camera according to claim 1, as shown in FIG. 1 (a), the zooming command causes the ratio of two adjacent focal lengths of the photographing lens 101 to be detected to be substantially constant at a plurality of positions. The above problem is solved by providing the control means 105 for controlling the driving means 103 so as to change the focal length of the taking lens 101 stepwise according to the position. In the electric zoom camera according to claim 1, when the command unit 104 commands the step zoom,
Control means 10 based on the position signal from the detection means 102
5 drives the taking lens 101. The ratio of the two adjacent focal lengths of the taking lens 101 set by this is made substantially constant. Further, as shown in FIG. 1B, the electric zoom camera according to claim 2 has two focal lengths of the photographing lens 101 at the time of outputting sequential position signals output for each predetermined movement amount of the photographing lens 101. The detection means 102 is configured to output a position signal such that the ratio of the two becomes substantially constant at a plurality of positions, and the control means 105 controls the driving means 107 in accordance with the position signal detected at the time of the zooming command, and the photographing lens 102. The above-mentioned problem is solved by changing the focal length of the stepwise. In the electric zoom camera according to the second aspect, when the command unit 104 commands the step zoom, the control unit 105 stops the taking lens 101 by the sequential position signals of the detection unit 102. Since the focal lengths when two adjacent position signals are output are made substantially constant in any focal length region, the ratio of the focal lengths always changes to be substantially constant.

[0006]

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

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

Reference numeral 12 denotes an intermediate helicoid, which is a camera 13
A helicoid portion 12b that meshes with the helicoid 13a of
Helicoid 12 that meshes with helicoid 9b of guide tube 9
a and a gear portion 12c that meshes with a transmission gear 14 that transmits a driving force from an electric drive portion (not shown). An encoder substrate 15 for position detection is fixed to a part of the intermediate helicoid 12, and the substrate 15 is fixed when the focal length is changed.
The encoder brush 16 slides on the conductive pattern.

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

FIG. 4 is an expanded view of the encoder substrate 15. The switching portion of the conductive pattern 15a, in other words, the pattern switching position at which the position signal obtained from the brush 16 changes is represented by a1, a2 ... A9. There is. When the focal lengths of the taking lens corresponding to this switching position are f1, f2 ... f9 respectively,

[Equation 1] As described above, the switching positions a1 to a9 are determined so that the ratio of two adjacent focal lengths is substantially constant. Since the photographing magnification is approximately inversely proportional to the focal length, each switching position a1 ~
The change in imaging magnification at two adjacent positions of a9 is the same at any position.

For example, when the photographing lens is a zoom lens of 35 mm to 70 mm, and the space between them is divided into 9 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 photometric value of the subject is input from the photometric circuit 32, the film sensitivity is input from the film sensitivity detection circuit 33, and the position signal described above is input from the encoder 34 to the arithmetic circuit 31. From the zooming command section 35, a zoom-up command and a zoom-down command at the time of manual electric zoom, a zoom command at the time 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 section 35. On the other hand, the exposure value is calculated by the photometric value, the film sensitivity, and the open F value of the taking lens read according to the position signal from the encoder 34, and the shutter 39 and the diaphragm 40 are drive-controlled via the diaphragm / shutter control circuit 38. .

The open F value is determined as follows.
In the case of automatic electric zooming and continuous zooming, 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 taking lens is not controlled by the position signal from the encoder 34, but the taking lens of the taking lens is output by the output or disappearance of the signal of the operator's zoom up command or zoom down command. Since the focal length is controlled, there is a high possibility that the taking lens will be controlled at an arbitrary position between the two switching positions. Therefore, encoder 3
Instead of the open F value corresponding to the position signal obtained from 4,
The exposure value is calculated by the open F value corresponding to the intermediate focal length of two adjacent position signals. Therefore, the arithmetic circuit 3
1 is provided with a correspondence table of the position signals and the open F values corresponding to the intermediate focal lengths of these position signals, and the open F value is obtained as described above. And automatic electric zooming,
Two tables are used by switching by manual electric zooming.

In the above construction, the front lens group 1 and the rear lens group 2 are the photographing lens 101, the encoder 34 is the detecting means 102, and the zoom motor 37 is the driving means 103.
The zooming command section 35 constitutes the command means 104.

The operation of the camera having such a structure will be described when the zooming command unit 35 commands, for example, continuous zoom shooting. When zoom continuous shooting is instructed and the release button is operated, the front lens group 1 and the rear lens group 2 are moved by the zoom motor 3
Driven by 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 is stopped and the focal length of the taking lens is set to 35 mm. After that, the front lens group 1
Are driven for automatic focusing. Then, the open F value is obtained from the position signal indicating that the focal length is 35 mm,
The shutter speed and the aperture value are calculated according to the photometric value and the film sensitivity, and the control circuit 38 drives and controls the aperture 39 and the shutter 40 to take an image. The film is then rolled up, after which the taking lens is, for example, 49.5.
The focal length is set to mm, and shooting is performed as described above.
Further, subsequently, the taking lens is set to a focal length of, for example, 70 mm, and the taking is performed simultaneously. The degree of change in the shooting magnification of the three photographs obtained by such continuous zooming is equally easy to see.

On the other hand, when a command to zoom up by one step is issued from the zooming instruction section 35, the front and rear lens groups 1 and 2 are driven by the zoom motor 37, and the focal length becomes one step longer than at the present time. For example, as shown in Table 1, it was changed from 35 to 38.7 mm, and by operating the release button, the open F value corresponding to the position signal of 38.7 mm was looked up from the table, and the exposure value was the same as above. Is decided and shooting is done.

In the case of manual electric zooming, the focal length of the taking lens can be set to an arbitrary value by a zoom-up command or a zoom-down command from the zooming command section 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 always at the switching position a4, but may be at any position between a4 and a5. From the above, the open F value corresponding to the focal length intermediate 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 by the open F value of the average focal length of, the accuracy of the exposure amount can be improved.

FIG. 6 is a diagram in which the switching positions a1 to a9 are displaced from each other 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 command unit 35, whether it is zooming from the wide to tele direction or zooming from the tele to wide direction, for example, from the wide to tele direction. The desired switching position is detected by the directional movement and the motor 37 is stopped to improve the accuracy of focal length setting due to backlash of the photographing lens drive system. This technique is disclosed in, for example, Japanese Patent Application No. 61-291950. In this case, since the movement direction of the photographing lens at the time of stop is always one direction, the movement 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, an error due to inertia can be prevented, and more accurate control can be performed.

In the above, the pattern is set so that the ratio of the sequential position signals obtained from the encoder 34 is substantially constant, and the photographic lens is zoomed stepwise. A position signal indicating the position of the taking lens may be continuously output, and stepwise zooming may be performed by the processing of the arithmetic circuit 31. In this case, the stepwise zooming and the conventional continuous zooming may be selected as desired.

[0020]

According to the first and second aspects of the present invention, the ratio of two adjacent focal lengths of the focal lengths which are changed stepwise is set to be substantially constant. Even on the side, the degree of change in the shooting magnification is constant, and you can get a clear photo. Further, according to the invention of claim 4, the movement direction when the photographing lens is stopped is one direction regardless of the zooming direction, and the switching position of each position signal is shifted by the shift due to the inertia of the photographing lens. The accuracy of focal length setting is further improved.

[Brief description of drawings]

FIG. 1 is a diagram for responding to a complaint.

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

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a development view of a printed circuit board according to an 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 the printed circuit board.

[Explanation of symbols]

 1 Front Group Lens 2 Rear Group Lens 15 Printed Circuit Board 15a Conductive Pattern 16 Brush 31 Calculation Circuit 34 Encoder 35 Zooming Command Section 37 Zoom Motor 101 Photographing Lens 102 Detecting Means 103 Driving Means 104 Commanding Means 105 Control Means

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[Procedure amendment]

[Submission date] May 22, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

[0003]

By the way, in the automatic electric zoom camera, the open F value of the taking lens corresponding to the focal length at each step position is stored in a table in advance,
Opening the step position set by step zooming F
Since the value can be read and the exposure value can be calculated, 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, and therefore the photographing lens is often set to a position other than the step position of automatic electric zoom. At such a set position intermediate between the step position and the step position, the set position itself cannot be detected unless a position detection device for continuously detecting the zoom position is provided. The 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 cannot be obtained for any manual zooming position. Of course, if a device for continuously detecting the zoom position is provided, it is possible to obtain the focal length and the open F value with respect to the intermediate set position as described above. It may be desired to omit such a zoom position detection device.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

An object of the present invention is to provide an electric zoom camera which performs optimum exposure control based on the open F value with respect to the focal length of the set position, even when manually zooming to a position other than the step position of the automatic electric zoom. Especially.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

[0005]

The present invention will be described with reference to FIG. 1. The invention of claim 1 is position detecting means 101 for outputting a position signal 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 the position signal output from the position detecting means 101 in response to the step zoom command and for setting the taking lens at any position in response to the manual zoom command. Is an electric zoom camera equipped with 102,
The open F value of the taking lens corresponding to the focal length f of the step positions a1 to an and two adjacent step positions am,
The position signal output from the position detection unit 101 and the F value storage unit 103 that stores the open F value of the taking lens corresponding to the intermediate focal length f of a (m + 1) (m = 1 to n−1) On the basis of the above, an exposure control unit 104 is provided which controls the exposure by reading the open F value corresponding to the setting position of the taking lens from the F value storage unit 103. Further, the invention of claim 2 is an electric zoom camera including position detecting means 101 for outputting a position signal at a plurality of predetermined positions a1 to an, and zoom driving means 102 for setting the photographing lens at an arbitrary position. And the open F value of the taking lens corresponding to the focal lengths f of the plurality of positions a1 to an and two adjacent positions a.
An F value storage unit 103 that stores an open F value of the taking lens corresponding to an intermediate focal length f of m, a (m + 1) (m = 1 to n−1), and a position output from the position detection unit 101. And an exposure control unit 104 for performing exposure control by reading out an open F value corresponding to the setting position of the photographing lens from the F value storage unit 103 based on the signal. Further, the position detecting means 101 of the electric zoom camera according to claim 3 has a conductive pattern corresponding to a plurality of positions, and a brush that slides on the conductive pattern in association with zooming of the photographing lens.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

In the above structure, the front lens group 1 and the rear lens group 2 are photographing lenses, the encoder 34 is position detecting means, and the arithmetic circuit 31, the motor drive circuit 36 and the zoom motor 37 are zoom drive means. The circuit 31 constitutes an F value storage means and an exposure control means, respectively.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Delete

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction content]

[0020]

According to the first aspect of the invention, the stepping zooming of the photographing lens is performed while detecting the step position by the position detecting means which outputs the position signal at a plurality of predetermined step positions, and the photographing lens is moved to an arbitrary position. With an electric zoom camera that performs manual zooming that sets the taking lens, the opening F value of the taking lens corresponding to the focal length at the step position and the opening F value of the taking lens corresponding to the intermediate focal length between two adjacent step positions. And remember
Based on the position signal output from the position detecting means, the open F value corresponding to the set position of the photographing lens is read out to control the exposure, so that a device for continuously detecting the zoom position is not installed. Even when manual zooming is performed to a position other than the step position, the optimum exposure value can be calculated based on the open F value with respect to the focal length of the set position, and the exposure control accuracy can be improved. Further, according to the invention of claim 2, a position detecting means for outputting a position signal at a plurality of predetermined positions is provided, and the open F value of the photographing lens corresponding to the focal lengths of the plurality of positions and the adjacent two. The open F value of the taking lens corresponding to the focal length in the middle of the position is stored, and the taking lens of the taking lens is stored based on the position signal output from the position detecting means during manual zooming for setting the taking lens at an arbitrary position. Since the exposure F value corresponding to the set position is read out to perform the exposure control, 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 other than the step position is not set. Even when the position is manually zoomed, the optimum exposure value can be calculated based on the open F value for the focal length of the set position, and the exposure control accuracy can be improved. Kill. Further, according to the invention of claim 3, the position detecting means is constituted by the conductive pattern corresponding to a plurality of positions and the brush sliding on the conductive pattern in association with the zooming of the photographing lens, so that the structure is simple. The inexpensive position detection device can reduce the cost and size of the electric zoom camera.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of reference numerals] 1 front lens group 2 rear lens group 15 printed circuit board 15a conductive pattern 16 brush 31 arithmetic circuit 34 encoder 35 zooming command section 37 zoom motor 101 position detecting means 102 zoom driving means 103 F value storage means 104 exposure control means

[Procedure Amendment 9]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

FIG.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Nakamura 1-6-3 Nishi-oi, Shinagawa-ku, Tokyo Nihon Kogaku Kogyo Co., Ltd.

Claims (4)

[Claims] 1. A photographic lens having a zooming function, a detecting means for detecting a focal length of the photographic lens, a driving means for zoom driving the photographic lens, a commanding means for instructing zooming, and 2 adjacent to each other by a zooming command. Control means for controlling the driving means to change the focal length of the photographing lens in steps according to the detected position of the photographing lens so that the ratio of the two focal lengths becomes substantially constant at a plurality of positions. A characteristic electric zoom camera. 2. A photographic lens having a zooming function, a driving means for driving the photographic lens to zoom, a command means for instructing zooming, and a position signal output for each predetermined movement amount of the photographic lens. Detecting means for outputting a position signal such that the ratio of the two focal lengths of the photographing lens at the time of outputting the position signal is substantially constant at a plurality of positions; and controlling the driving means according to the position signal detected at the time of the zooming command, An electric zoom camera, comprising: a control unit that changes the focal length of the taking lens in steps. 3. The electric zoom camera according to claim 2, wherein the detection unit includes a conductive pattern and a brush that relatively slides on the conductive pattern in accordance with zoom driving of the photographing lens. An electric zoom camera, which outputs a position signal upon contact with a pattern. 4. The electric zoom camera according to claim 3, wherein the control unit controls the photographing lens by a relative movement of the brush in one of a tele-direction and a wide-direction to a tele-direction with respect to the conductive pattern. An electric zoom camera characterized in that the position signal switching position of the conductive pattern is shifted by a predetermined amount by an amount corresponding to the amount of movement of the photographing lens due to inertia until the photographing lens stops after the position signal is output. .