JP3478563B2 - camera - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an electronic zoom and an optical zoom.
The present invention relates to a camera that performs zooming by linking the frames .

[0002]

2. Description of the Related Art As a conventional focus system, a rear focus system such as that disclosed in Japanese Patent Publication No. 52-15226 is often used in order to reduce the size and weight of a video camera (movie). . This is for focusing using a lens group located closer to the image sensor than the variator lens. Even when changing the focal length (magnification) while fixing the shooting distance, not only the variator lens but also the master It is also necessary to move the lens (focus lens). That is, the position of the focus lens is determined by a function having two variables, the shooting distance and the focal length.

At present, a microcomputer is generally used to control such a complicated focus lens. The position of the variator lens (movement amount from the reference position) is used instead of the focal length for control, and the position of the focus lens (from the reference position) with respect to the position of the variator lens is used for some typical shooting distances (subject distances). The data of the curve that represents the amount of movement) is used. This curve is called a trace curve, and the operation of moving the focus lens along the trace curve when the variator lens is moved is called a zoom trace. An example of the trace curve is shown in FIG.

In the consumer movie, the zoom function is a necessary and important function, but in the case of the optical zoom as described above, the size and weight of the high-magnification zoom lens are large, which prevents the movie from becoming smaller and lighter. Becomes

Therefore, as a method of solving such a problem, electronic zooming, that is, a method of expanding a photographed image by vertically and horizontally extending a video signal by electronic signal processing without using a lens optical system There is. An example of a proposal for such an electronic zoom is, for example, Proceedings of the 1989 National Conference of the Television Society of Japan, pp. 161 to 162.
Page (July 1989), and Proceedings of the 1991 National Conference of the Television Society of Japan, 359-360 (1991).
July, 2007).

In this proposed example, vertical expansion is performed by so-called "thinning transfer" by controlling readout of the image pickup device, and then horizontal expansion is performed by signal processing using a line memory. However, a method using signal processing for both horizontal and vertical is also conceivable.

Conventionally, such an electronic zoom has been used in combination with an optical zoom to realize a high zoom ratio. Usually, in the range of low zoom ratio, the optical zoom is used without using the electronic zoom, and the electronic zoom is used when further enlarging after the variator lens reaches the telephoto end. On the contrary, when moving to the wide-angle side, first decrease the zoom ratio of the electronic zoom, and when it becomes 1 (that is,
When the electronic zoom function stops working), use the optical zoom to start moving the variator lens to the wide-angle side.
By such a method, it is possible to minimize deterioration of image quality such as resolution due to electronic zoom.

[0008]

However, in the above-mentioned prior art, when zoom tracing is performed in the optical zoom, the focus lens must be largely moved by a slight movement of the variator lens in the portion where the inclination of the trace curve is large. I have to. Therefore, in order to increase the zooming speed, it is necessary not only to move the variator lens at high speed, but also to move the focus lens at high speed, which makes the drive motors for both the variator lens and the focus lens large and heavy, and increases power consumption. There was a problem of inviting. Furthermore, as shown in FIG. 10, the slope of the trace curve in the vicinity of the telephoto end is considerably larger than that in the wide-angle end, so it is necessary to move the focus lens very quickly in the vicinity of the telephoto end. Since there is a limit, even if an attempt is made to increase the zooming speed as a whole, there is a problem that the zooming speed is limited due to such a slope of the trace curve near the telephoto end.

When zooming from the wide-angle side to the telephoto side when the object distance is shorter than the close-up distance, even if the wide-angle side is in focus, it becomes impossible to focus as the zoom lens approaches the telephoto end. Even if the variator lens reaches the telephoto end and the electronic zoom operates in such a situation, the electronic zoom function cannot be used because the electronic zoom is out of focus. Therefore, when the subject distance is a certain amount or more, a zoom ratio of several tens to several tens of times can be obtained by a combination of the optical zoom and the electronic zoom, but if the subject distance is short, it is at most 2-3. Only a double zoom ratio can be obtained, and there is a problem in that there is an imbalance in operability.

An object of the present invention is to solve the above-mentioned problems of the prior art, to reduce the size and weight of a lens drive motor, to reduce power consumption, and to increase the zooming speed. Even if the subject distance is short,
An object of the present invention is to provide a camera capable of obtaining a zoom ratio of ten-odd times to several tens of times by combining an optical zoom and an electronic zoom.

[0011]

In the range where the inclination of the trace curve is large, the moving speed of the variator lens is reduced, and zooming by electronic zoom is performed by an amount that compensates for the reduced speed of the variator lens.

When entering an unfocusable area due to zooming, the variator lens is stopped immediately before entering that area, and instead, electronic zoom is used to perform zooming.

The maximum magnification of the electronic zoom when the subject distance is short is set larger than the maximum magnification of the electronic zoom when the subject distance is long. Alternatively, the product of the variable magnification of the optical zoom and the maximum magnification of the electronic zoom is made substantially constant at any object distance.

When the electronic zoom is used while the variator lens is stopped halfway, when the subject distance increases and the optical zoom changes to a focusable state, the variator lens is moved to the telephoto side and at the same time the electronic zoom is turned on. Reduce the scaling factor so that the overall scaling factor is kept approximately constant.

When the subject distance is small when the variator lens is on the telephoto side, the reverse operation is performed.

[0016]

In the range where the inclination of the trace curve is large, the moving speed of the variator lens is reduced to enable control along the trace curve even if the moving speed of the focus lens is low, thus reducing the size and size of the drive motor. Power consumption can be achieved. On the other hand, by performing zooming by the electronic zoom by an amount that compensates for the speed reduction of the variator lens, a high zooming speed can be obtained at a constant speed as an image effect.

When entering an unfocusable area due to zooming, the variator lens is stopped immediately before entering the area, and instead, the electronic zoom is used to perform zooming, thereby effectively utilizing the electronic zoom that could not be utilized conventionally. To
Zooming with a larger zoom ratio is possible.

If the product of the magnification of the optical zoom and the maximum magnification of the electronic zoom is made substantially constant at any object distance, it is possible to perform zooming at a constant ratio regardless of the object distance.

When the variator lens is stopped halfway and the electronic zoom is being used, and when the subject distance increases and the optical zoom changes to a focusable state, the variator lens is moved to the telephoto side and at the same time the electronic zoom is used. Reduce the scaling factor to keep the overall scaling factor constant. With this method, the state becomes the same as that after zooming from the wide-angle side to the telephoto side with a large object distance, and the performance of the optical zoom is utilized to prevent image quality deterioration and to obtain operational uniformity. Further, even when the subject distance continuously changes, it is possible to focus on following this.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a block diagram showing the configuration of the lens system used in this embodiment. In FIG. 2, 201, 2
Reference numerals 02, 204, and 205 are lens groups, 201 is a front lens, 202 is a variator lens, 204 is a relay lens, and 205 is a focus lens. Further, 203 is a diaphragm, 206 is an image sensor, 207 is a signal processing unit, 208 is a video signal output terminal, 209 is a microcomputer, and 210 and 211 are drive motors.

Among the lens group, the front lens 201 and the relay lens 204 are fixed. On the other hand, the focus lens 205 is driven by the drive motor 210 and is movable in the optical axis direction, and serves to adjust the focus. The variator lens 202 is also driven by the drive motor 211 and is movable in the optical axis direction, and this has a zooming effect. The image formed by these optical systems is converted into an electric signal by the image sensor 206, various signal processing including electronic zoom processing is performed by the signal processing unit 207, and the signal is output from the video signal output terminal 208. The microcomputer 209 controls the lens system including aperture control (not shown).

The trace curve for the focus lens 205 in FIG. 2 is as shown in FIG.
As long as optical scaling / focus adjustment is performed optically, zoom tracing may be performed using this trace curve.

In the present embodiment, an electronic zoom for performing a scaling process on an image signal obtained from the image pickup device 205 by using electronic means (that is, the signal processing unit 7) is combined with an optical zoom to provide a wide range. It enables zooming.

A method of combining the optical zoom and the electronic zoom will be described with reference to FIG. FIG. 3 is an explanatory diagram for explaining a combination method of the optical zoom and the electronic zoom in this embodiment. In FIG. 3, a trace curve is not taken into consideration for the sake of convenience, and the relationship between the variable magnification (zoom magnification) and the subject distance is shown. In the present embodiment, as shown in FIG. 3, in the range from the subject distance of 1 m to infinity, the magnification of the optical zoom is set to 8 times, and the electronic zoom of 2 times is combined with this to obtain the magnification of 16 times. There is.

In FIG. 3, a portion shown as an optical zoom area is an optically focusable range. Since the movable range of the focus lens 205 for focus adjustment is structurally limited, for example, when the subject distance is 10 cm, a magnification of 8 times cannot be obtained, and a magnification of about 4 times is obtained. . If the variator lens 202 is moved to the telephoto side in order to obtain a large zoom ratio for such a subject distance, focus adjustment by the focus lens 205 becomes impossible. The area of the subject distance in which the scaling ratio is limited in this way is hereinafter referred to as a macro area.

The limitation of the variable magnification ratio in the optical zoom area or the limitation of the object distance that can be focused is apparent from the trace curve of FIG. For example, if the subject distance is 20
When cm, the position of the variator lens 202 is from 0 mm to 8
Although zoom trace in the range of mm is possible, if the variator lens 202 moves beyond this range and moves further to the telephoto side, the trace curve will exceed the movable range of the focus lens 205.

In FIG. 3, an electronic zoom area A is an area where a focused electronic zoom effect can be obtained in the conventional electronic zoom. Therefore, conventionally, when the subject distance is shorter than 1 m, zoom tracing is impossible as described above. Therefore, even if the electronic zoom is used to increase the magnification ratio, the focused image will not be obtained. I couldn't get it.

Further, in FIG. 3, electronic zoom areas B and C are areas which can be newly focused by the present invention. That is, for example, when the object distance is closer than 1 m and the magnification is gradually increased from 1 ×, the variator lens 202 is stopped at the boundary between the optical zoom area and the area B, and thereafter, the electronic zoom is used. Scale.

In addition, the electronic zoom area C is used to obtain a constant magnification (16 times in this embodiment) regardless of the subject distance. In this case, it is necessary to set the maximum variable magnification by the electronic zoom to about 8 times. Since the magnification change by the electronic zoom is performed by the electronic signal processing in the signal processing unit 207, it is easy to increase the magnification change.

On the other hand, when the magnification of the electronic zoom is increased, the deterioration of the image quality is increased. For applications where the image quality is not desired to be deteriorated so much, a method may be considered in which the maximum zoom ratio by electronic zoom is set to 2 and the electronic zoom area C is not used.

Next, the zooming operation of this embodiment will be described. In the optical zoom area, the same zoom tracing as in the conventional case is performed while moving the variator lens 202, and in the electronic zoom area A, B or C, the signal processing unit 207 is performed without moving the variator lens 202.
Magnification is changed by electronic signal processing in.

Further, at a place where the optical zoom area is switched to the electronic zoom area, control is performed so that the variable magnification by the optical zoom and the variable magnification by the electronic zoom change at the same time. This state is shown in FIG. In FIG. 4, the scaling factor on the vertical axis is a logarithmic scale.

At the position where the variator lens 202 is at the wide-angle end, both the optical zoom and the electronic zoom have the minimum magnification (1
Times). When increasing the zoom ratio from this state, the zoom ratio of the optical zoom is first increased (section 1 in FIG. 4). Next, when the optical zoom magnification becomes large and the variator lens 202 approaches the telephoto end (section 2 in FIG. 4), the moving speed of the variator lens 202 (that is, the optical zoom magnification change speed) is reduced. At the same time, the zoom ratio of the electronic zoom is gradually increased. When the variator lens 202 reaches the telephoto end (section 3 in FIG. 4), the change of the zoom ratio of the optical zoom is stopped, and only the zoom ratio of the electronic zoom is changed. The rate of change of the electronic zoom magnification at this time is higher than the rate of change of the electronic zoom magnification in the section 2.

In this way, the moving speed of the variator lens 202 (that is, the changing speed of the zoom ratio of the optical zoom) is reduced in the vicinity of the telephoto end where the inclination of the trace curve becomes large. The speed can be reduced, and the variator lens 202 and the focus lens 204 can be driven by a drive motor that is smaller, lighter, and consumes less power than ever before. Moreover, by operating the electronic zoom at the same time, the total scaling ratio in the finally obtained image obtained by combining the optical zoom and the electronic zoom changes at a constant speed as shown in FIG. It becomes zooming.

Further, by performing such control, even if the variator lens 202 cannot be suddenly stopped or started in the optical zoom due to the inertia of the variator lens 202, etc. The zoom and electronic zoom can be smoothly connected to each other.

In the example shown in FIG. 4, the subject distance is 1
When the distance is greater than m, and when the optical zoom area shown in FIG. 3 moves to the electronic zoom area A, the subject distance is 1
Even when the distance is closer than m, and when moving from the optical zoom area shown in FIG. 3 to the electronic zoom area B, only the position for decelerating / stopping the change in the magnification of the optical zoom is different, and other operations are performed in the same manner. .

FIG. 1 shows a case where the object distance is infinity and 1 cm.
The case of is compared and shown. When the subject distance is more than 1 m such as infinity, the optical zoom is used up to a magnification of 8 times. Therefore, when the magnification of the optical zoom where the trace curve shown in FIG. As indicated by 1 (1), the moving speed of the variator lens 202 (that is, the changing speed of the magnification of the optical zoom 8) is reduced, and at the same time, the electronic zoom is started to move.

On the other hand, when the subject distance is shorter than 1 m, the optical zoom is used with a magnification of 6 or less. For example, as shown in FIG. 1 (2), when the subject distance is 1 cm, the moving speed of the variator lens 202 (that is, the changing speed of the optical zoom scaling factor) when the optical zoom scaling factor is around 2 times. Is lowered and stopped at the double. At this time, as in the case of FIG. 1A, the electronic zoom is operated so that the changing speed of the total scaling ratio becomes constant. In the case of FIG. 1 (2), the zoom ratios of the optical zoom and the electronic zoom may be changed at the same time only while the changing speed of the zoom ratio of the optical zoom is constant until the stop. Therefore, the time that changes at the same time is shorter than that in the case of FIG.

The example shown in FIG. 4 is for zooming from the wide-angle side to the telephoto end. Conversely, when zooming from the telephoto end to the wide-angle side, the time axis of FIG. 4 is reversed. It suffices to perform the operation as described above.

Further, in the example shown in FIG. 4, control is performed so that the time change of the magnification of the optical zoom becomes exponential. However, in an actual lens, when the variator lens 202 is moved at a constant speed, the variable magnification of the optical zoom does not exactly change exponentially. Therefore, by using the relationship between the position of the variator lens 202 and the magnification of the optical zoom, which is optically determined, the moving speed of the variator lens 202 is controlled so that the magnification of the optical zoom changes exponentially. There is. On the other hand, in an optical system in which the relationship between the position of the variator lens 202 and the magnification of the optical zoom can be regarded as an exponential function, even if the moving speed of the variator lens 202 is controlled to be constant,
The same effect can be obtained.

Further, in the example shown in FIG. 4, the changing speed (exponential function) of the zoom ratio of the optical zoom is switched between two steps in the sections 1 and 2, but the speed is gradually decelerated or accelerated. You may control. In this case, the electronic zoom is controlled so as to gradually accelerate or decelerate correspondingly to the rate of change of the zoom ratio.

Next, the zoom speed control method in this embodiment will be described. FIG. 5 is a flowchart showing an example of the zoom speed control method in this embodiment. When the target zoom speed is given, first, the change speed of the magnification of the optical zoom (hereinafter referred to as the optical zoom speed) is determined. The optical zoom speed is determined by the target zoom speed when the position of the variator lens 202 is on the wide angle side, and when it corresponds to the section 2 in FIG. 4, the target value is determined so as to decelerate as described above.

Further, as described above, the target moving speed of the variator lens 202 is obtained by obtaining the target moving speed of the variator lens 202 from the optical zoom speed using the relationship between the zoom ratio of the optical zoom and the position of the variator lens 202. Is determined. In many cases, the target moving speed of the variator lens 202 can be obtained with sufficient accuracy even by a simple method such as multiplying the optical zoom speed by a constant coefficient.

Next, the electronic zoom speed is obtained by subtracting the optical zoom speed from the target zoom speed. With such control, the above-described zooming operation can be performed.

The above control mainly refers to the changing speed of the variable magnification, but a method of determining the target variable magnification from the current variable magnification and the target zoom speed is also possible. FIG. 6 is a flowchart showing another example of the zoom speed control method in this embodiment.

The variator lens 202 is used when a small DC motor is used to drive the variator lens 202.
When the factor of the speed control is unstable, the control method shown in FIG. 6 is effective. In this method, the target zoom speed and the variator lens 20 are set when the electronic zoom speed is determined.
Actual variator lens 2 instead of target moving speed 2
The moving speed of 02 is used. The moving speed of the variator lens 202 can be easily obtained by the differential value (or difference value) of the output of the position sensor used for zoom tracing. Also, a speed sensor may be separately provided.

The zoom control described above may be continuous control, but is also suitable for sample control using a microcomputer or the like. In particular, it can be realized by a single microcomputer in combination with zoom trace control and automatic focusing control.

Next, focusing in this embodiment will be described. FIG. 7 is an explanatory diagram for explaining the focusing operation in this embodiment.

The focusing operation is represented by a vertical movement in FIG. 7 since it is considered that the magnification ratio is unchanged and only the object distance is changed. Of these, if the subject distance changes only within the optical zoom region or only within the electronic zoom region A, focusing can be performed by moving the focus lens 204 as in the conventional case (eg, arrow 701, 702). However, the situation is different when the subject distance changes, including the electronic zoom region B or C, as indicated by arrows 703 and 704. Therefore, as a representative, the focusing operation in the case shown by the arrow 703 will be described.

FIG. 8 is an explanatory diagram showing the relationship between the subject distance and the magnifications of the optical zoom and the electronic zoom for focusing in the case shown by the arrow 703 in FIG. Unlike FIG. 7, the abscissa represents the subject distance and the ordinate represents the magnification, and the magnification is shown for each of the optical zoom and the electronic zoom.

In the case shown in FIG. 8, the total magnification is about 3, and when the subject distance is shorter than 10 cm, the electronic zoom area B is set. For example, when the subject distance is 1 cm, the zoom ratio is 2 times with the optical zoom and 1.5 times with the electronic zoom. When the subject distance is more than 10 cm, the optical zoom is 3 times and the electronic zoom is 1 time. And the total magnification is constant at any subject distance. In the case of focusing, a smooth transition is made between them. As shown in FIG. 8, the magnification of the optical zoom and the electronic zoom are controlled according to the subject distance.

By the way, in the portion where the magnification of the optical zoom changes in FIG. 8, as shown by the trace curve in FIG. 10, even if only the variator lens 202 is moved with the position of the focus lens 204 kept constant, focusing is achieved. Subject distance changes. Focusing can be performed by utilizing this property. In addition, when combined with an automatic focusing mechanism using a video signal, which has been used in recent years, the focus lens 2 can be used for small focus movement.
02, using only the variator lens 2
A method such as moving 04 is adopted.

However, in FIG. 7, when the magnification of the optical zoom is 8 and the subject distance approaches, for example, from 1 m to less than 1 m, the variator lens 202 is moved to focus. It is necessary to reduce the magnification from 8 times to about 4.6 times or less. However, in this case, as is clear from the trace curve of FIG. 10, when the magnification of the optical zoom is 8 and the subject distance is 1 m, even if only the variator lens 202 is moved with the position of the focus lens 204 kept constant, While the variator lens 202 is being moved (that is, until the magnification of the optical zoom reaches about 4.6 times), it is not possible to focus on an object at a distance of less than 1 m. That is, the subject distance does not continuously change when focusing is performed. This phenomenon may cause inconvenience especially in the automatic focusing mechanism.

Therefore, by slightly changing the electronic zoom region and the optical zoom region, a structure suitable for the automatic focusing mechanism can be obtained. An example thereof is shown in FIG. That is, the area D in FIG. 9 is newly set as the electronic zoom area. As a result, the closest object distance that can be focused on changes monotonically with respect to the change in the optical zoom magnification, regardless of the optical zoom magnification. Therefore, focusing as shown by the arrow 901 can be continuously performed.

[0056]

According to the present invention, in a range where the trace curve has a large inclination, the moving speed of the variator lens is reduced, so that the control along the trace curve is possible even if the moving speed of the focus lens is small. Become. In addition, by reducing the moving speed of the focus lens in this way, it is possible to drive the lens with a drive motor that is smaller and lighter in weight and consumes less power than before, thus achieving a reduction in the size and weight of the drive motor and lower power consumption. it can. On the other hand, by performing zooming by electronic zoom by an amount that compensates for the speed reduction of the variator lens, a high zoom speed can be obtained at a constant speed as an image effect.

When entering a non-focusable area by zooming using the optical zoom, the variator lens is stopped immediately before entering the area, and instead the electronic zoom is used to perform zooming, which cannot be used conventionally. The electronic zoom can be effectively used, and even when the subject distance is short, a zoom ratio of a dozen to several tens of times can be obtained by combining the optical zoom and the electronic zoom.

If the product of the variable magnification by the optical zoom and the maximum variable magnification of the electronic zoom is made substantially constant at any object distance, it is possible to perform zooming at a constant ratio regardless of the object distance.

When the variator lens is stopped halfway and the electronic zoom is being used and the subject distance becomes large and the focus can be achieved only by the optical zoom, the variator lens is moved to the telephoto side and the electronic zoom is performed at the same time. Reduce the zoom ratio of to keep the overall zoom ratio (zoom ratio) constant. With this method, when the subject distance is large, the state will be the same as after zooming from the wide-angle side to the telephoto side, and the performance of the optical zoom will be used to prevent image quality deterioration and ensure operational uniformity. To be

It is possible to focus on an object located within a certain range regardless of the zoom magnification.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing a temporal change of a zoom ratio by an optical zoom and a zoom ratio by an electronic zoom in one embodiment of the present invention, when an object distance is infinity and when it is 1 cm. .

FIG. 2 is a configuration diagram showing a configuration of a lens system used in an embodiment of the present invention.

FIG. 3 is an explanatory diagram illustrating a method of combining an optical zoom and an electronic zoom according to an embodiment of the present invention.

FIG. 4 is a characteristic diagram showing a temporal change of a variable magnification ratio by optical zoom and an electronic zoom ratio according to an embodiment of the present invention.

FIG. 5 is a flowchart showing an example of a zoom speed control method according to an embodiment of the present invention.

FIG. 6 is a flowchart showing another example of the zoom speed control method in the embodiment of the present invention.

FIG. 7 is an explanatory diagram illustrating an operation of focusing according to the embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a relationship between a subject distance and magnifications of optical zoom and electronic zoom for focusing in a case as indicated by an arrow 703 in FIG. 7.

FIG. 9 is an explanatory diagram for explaining another combination method of the optical zoom and the electronic zoom in the embodiment of the present invention.

FIG. 10 is a characteristic diagram showing an example of a trace curve according to the related art or the present invention.

[Explanation of symbols]

201 ... front lens, 202 ... variator lens,
203 ... Aperture, 204 ... Relay lens, 205 ... Focus lens, 206 ... Image sensor, 207 ... Signal processing unit,
208 ... Video signal output terminal, 209 ... Microcomputer, 210 ... Focus lens drive motor, 211 ...
Variator lens drive motor.

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Claims (5)

(57) [Claims] 1. A and a zoom lens having an optical zooming action and focus lens that performs focusing, optical's
The original scaling factor of the camera depends on the subject distance
Area of such subject distance, macro area
A lens system, a driving means for moving the zoom lens and the focus lens in the optical axis direction, an image sensor for converting an image of a subject formed by the lens system into an electric signal, and the image sensor An electronic zoom unit that electronically magnifies an image of a subject represented by the electric signal by performing signal processing on the output electric signal, and a control unit that controls the driving unit and the electronic zoom unit. In a camera provided with the zoom lens, the control unit increases the zoom ratio by the zoom lens when increasing the total zoom ratio obtained by using both the zoom ratio by the zoom lens and the zoom ratio by the electronic zoom unit. , The total magnification is the macro area of the lens system.
Depends on the range of zoom magnification change that depends on the subject distance
After exist and becomes first value is set, reduce the rate of change of magnification by the zoom lens, the larger the magnification by the electronic zooming unit, the total magnification is, the
Zoom changes depending on the subject distance in the macro area of the lens system.
When the value reaches the second value set depending on the change range of the magnification, the zoom ratio by the zoom lens is stopped from increasing and the change speed of the zoom ratio by the electronic zoom is increased to increase the total zoom ratio. A camera, characterized in that the drive means and the electronic zoom means are controlled so that the changing speed becomes substantially constant when viewed exponentially. 2. When reducing the total magnification, the magnification by the electronic zoom means is reduced, and when the total magnification reaches the second value, the rate of change of the magnification by the electronic zoom means. And the zoom ratio by the zoom lens is also reduced, and when the total zoom ratio reaches the first value, the zoom ratio by the electronic zoom means is stopped to be reduced, and the zoom ratio by the zoom lens is reduced. 2. The camera according to claim 1, wherein the driving means and the electronic zooming means are controlled so that the changing speed is increased and the changing speed of the total magnification is exponentially substantially constant. . 3. a zoom lens having an optical zooming action and focus lens that performs focusing, optical's
The original scaling factor of the camera depends on the subject distance
Area of such subject distance, macro area
A lens system, a driving means for moving the zoom lens and the focus lens in the optical axis direction, an image sensor for converting an image of a subject formed by the lens system into an electric signal, and the image sensor An electronic zoom unit that electronically magnifies an object image represented by the electric signal by performing signal processing on the output electric signal, and a control unit that controls the drive unit and the electronic zoom unit The camera is characterized in that the maximum value of the magnification change by the zoom lens is limited to a value that enables focusing by the focus lens for each subject distance. 4. The camera according to claim 3, wherein the maximum value of the zoom ratio by the zoom lens is changed continuously and monotonously according to the change of the subject distance. 5. The maximum value of the total zoom ratio obtained by using both zooming by the zoom lens and zooming by the electronic zooming unit is substantially constant regardless of the change in the subject distance. 4. The camera according to claim 3, wherein the maximum value of the magnification change by the zoom lens and the maximum value of the magnification change by the electronic zoom unit are changed complementarily according to the change of the subject distance.