JPH09233385A - Controller for zoom lens and its control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply an operation of dolly-back image pickup by recording a distance between an object and a camera, focal distance of a zoom lens and an image pickup distance in rehearsal image pickup and conducting zooming and focusing automatically in the going on the air image pickup. SOLUTION: A dolly position detection circuit 1 detects a moving distance of a dolly with a camera mounted thereon in a rehearsal image pickup, a focus ring position detection circuit 2 detects a focus ring position and a rotary angle of a zoom lens. Furthermore, a zoom ring position detection circuit 3 detects a zoom ring position being a focal distance of the zoom lens and a rotary angle. Then a CPU 5 stores the mutual relation among the distance between the object and the camera, the focal distance of the zoom lens and the image pickup distance, to a memory 4. In the case of on the air image pickup, zooming and focusing are conducted automatically based on the focus ring and the rotary angle of the zoom ring stored in the memory 4 by having only to move the dolly while keeping the image pickup direction constant so as to simplify the dolly-back image pickup operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device and a control method for a zoom lens, particularly for a TV camera.

[0002]

2. Description of the Related Art Conventionally, a dollyback is known as a shooting method for TVs and movies. Here, the dolly is a tripod provided with a pulley so that the camera can be freely moved. This dolly-back shooting method is designed so that when the main subject, which is the shooting target, and the background of this main subject are in a distant positional relationship, the dolly on which the camera is mounted approaches the main subject or from the main subject. Zooming is performed so that the composition, that is, the angle of view of the main subject is kept constant while moving in the direction away from the subject. As a result, it is possible to greatly change the shooting range of the background while keeping the angle of view of the main subject constant, and to shoot a powerful image.

[0003]

By the way, in the dolly-back, there are three operations: zooming for keeping the angle of view of the main subject constant, focusing on the main subject, and moving the dolly while keeping the shooting direction constant. Must be done at the same time.

However, the conventional camera has a problem that the photographer must perform these operations by himself, which makes the operation complicated.

It is possible to divide these operations among a plurality of people, but in this case, it is very difficult to match the three operations. Also, the same effect as dolly back can be obtained by using the image synthesizing method, but a blue back (a blue plate placed behind the main subject) is prepared, or an image synthesizing device is prepared. Since the necessity arises, the device becomes large-scale. Also, the synthetic image loses its naturalness.

The present invention has been made based on the above circumstances, and provides a zoom lens control device and control method capable of automatically performing zooming and focusing by moving a dolly on which a camera is mounted. That is the purpose.

[0007]

In order to solve the above-mentioned problems, a control device for a zoom lens according to a first aspect of the present invention comprises:
A detection unit that detects distance information between the subject and the camera, a table that indicates the relationship between the distance information, the information that specifies the focal length of the zoom lens, and the information that specifies the shooting distance of the zoom lens are stored. Information for identifying a focal length and information for identifying a shooting distance corresponding to the distance information detected by the detecting unit is read from the storage unit, and the focal length and the shooting distance identified by the read information. And a control means for controlling the zoom lens so that

According to a second aspect of the present invention, in the first aspect of the invention, the information for specifying the focal length in the storage means has a constant angle of view of the subject regardless of a change in the distance information. It is characterized by being stored as follows.

According to a third aspect of the present invention, there is provided a zoom lens control device, wherein first detecting means for detecting distance information between a subject and a camera, and each time the first detecting means detects distance information. Second detecting means for detecting information specifying the focal length of the zoom lens corresponding to the distance information, and photographing of the zoom lens corresponding to the distance information each time the distance information is detected by the first detecting means. Third detecting means for detecting information specifying a distance, distance information detected by the first detecting means, information specifying a focal length detected by the second detecting means, and the third detecting means Storage means for creating and storing a table showing the relationship with the information for specifying the photographing distance detected by the means, and for specifying the focal length corresponding to the distance information detected by the first detecting means from the storage means. Information and Reads information specifying the shadow distance, is characterized in that it comprises control means for controlling said zoom lens such that the focal length and the object distance specified by the read information.

According to a fourth aspect of the present invention, there is provided a zoom lens control method, which detects distance information between a subject and a camera, and specifies the distance information and information for specifying the focal length of the zoom lens and the shooting distance of the zoom lens. The information specifying the focal length and the information specifying the shooting distance corresponding to the detected distance information is read from the storage unit that stores the table indicating the relationship with the information to be read, and the focus specified by the read information is read. The zoom lens is controlled so that the distance and the shooting distance are set.

According to a fifth aspect of the present invention, in the fourth aspect of the invention, the information for specifying the focal length in the storage means has a constant angle of view of the subject regardless of changes in the distance information. It is characterized by being stored as follows.

According to a sixth aspect of the present invention, there is provided a zoom lens control method, which includes distance information between a subject and a camera, information specifying a focal length of the zoom lens and information specifying a photographing distance corresponding to the distance information. A step of detecting and creating a table showing the relationship between the distance information, the information specifying the focal length, and the information specifying the shooting distance, and storing the table in a storage medium;
The distance information between the subject and the camera is detected, the information specifying the focal length and the information specifying the shooting distance corresponding to the detected distance information are read from the storage medium, and specified by the read information. And a step of controlling the zoom lens so that the focal length and the photographing distance are obtained.

According to the present invention, a table showing the relationship between the distance information from the subject to be photographed, the information for specifying the focal length of the zoom lens, and the information for specifying the shooting distance of the zoom lens is stored in advance in the storage means. The detecting means sequentially detects the distance information between the main subject and the camera at the time of shooting, and the storing means stores the information specifying the focal length of the zoom lens and the information specifying the shooting distance corresponding to the detected distance information. The zoom lens is controlled so that the focal length and the shooting distance specified by the information are obtained. Therefore, a photographer or the like can automatically perform zooming and focusing simply by moving the dolly on which the camera is mounted. Therefore, for example, when performing dolly-back shooting using a camera to which the device of the present invention is applied, the photographer or the like keeps the angle of view of the main subject constant only by moving the dolly while keeping the shooting direction constant. Zooming and focusing on the main subject can be performed, and thus the operation of dolly-back shooting, which has been complicated in the past, can be simplified.

Another aspect of the present invention is to detect a distance information, focal length information and photographing distance information corresponding to the distance information, and create a table showing a relationship between the distance information, the focal distance information and the photographing distance information. By creating and storing, the shooting conditions can be stored by one learning. For example, in rehearsal photography or the like, it is possible to store the relationship between the distance from the main subject to the camera, the focal length of the zoom lens, and the shooting distance. As a result, in actual shooting, just by moving the dolly, zooming and focusing can be performed as in rehearsal.

[0015]

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

FIG. 1 is a schematic block diagram of a zoom lens control apparatus according to an embodiment of the present invention, FIG. 2 is a diagram for explaining an operation of writing various kinds of information in a memory in the apparatus of the present embodiment, and FIG. It is a figure for explaining automatic control of zooming and focusing in an embodiment device.

As shown in FIG. 1, the zoom lens control apparatus according to the present embodiment has a dolly position detecting circuit 1, a focus ring position detecting circuit 2, and a zoom ring position detecting circuit 3.
, Memory 4, central processor unit (CP
U) 5, the focus motor control circuit 6, the zoom motor control circuit 7, the focus ring position detection circuit 2 and the zoom ring position detection circuit 3 A / D which converts the analog signal into a digital signal and outputs it to the CPU 5. Conversion circuit 8 and C
Focus motor control circuit 6 and zoom motor control circuit 7 by converting a digital signal from PU 5 into an analog signal
And a D / A conversion circuit 9 for outputting to.

Although not shown, the dolly position detecting circuit 1 detects the movement of the dolly on which the camera using the apparatus of this embodiment is mounted. As the dolly position detection circuit 1, for example, an encoder or the like that detects rotation of a pulley provided on a leg portion can be considered. For example, a pulse signal is output from the encoder every time the pulley rotates by a predetermined rotation angle. Then, in the CPU 5 described later, the moving distance of the dolly is detected by multiplying the input pulse number by the moving distance of the dolly corresponding to the predetermined rotation angle of the pulley.

Although not shown, the focus ring position detection circuit 2 detects the position (rotation angle) of the focus ring of the zoom lens, which is shooting distance information. Also,
The zoom ring position detection circuit 3 detects the position (rotation angle) of the zoom ring, which is the focal length information of the zoom lens. Here, the focus ring is for moving the focus adjustment lens of the zoom lens to perform focusing. Further, the zoom ring is for moving the zoom lens of the zoom lens to perform zooming.
As the focus ring position detection circuit 2 and the zoom ring position detection circuit 3, for example, a potentiometer or the like can be considered.

The memory 4 is for storing a table showing the relationship between the distance information from the main subject to the camera, the focal length information of the zoom lens, and the photographing distance information of the zoom lens. In the present embodiment, information about the moving distance from the shooting start position of the dolly as the distance information from the main subject to the camera, information about the rotation angle of the zoom ring as the focal length information of the zoom lens, and the zoom lens Information about the rotation angle of the focus ring is used as the shooting distance information.

The relationship between the distance from the main subject to the camera, the focal length of the zoom lens, and the magnification of the zoom lens will be described. The height of the main subject is AB, the height of the image corresponding to the main subject formed on the image sensor through the zoom lens is A′B ′, the distance from the zoom lens to the main subject is a, and the distance from the zoom lens is If the distance to the image corresponding to the main subject on the image sensor is b and the image magnification of the main subject is m, m can be expressed by the following equation. A′B ′ / AB = b / a = m Expression (1) Further, when the focal length of the zoom lens is f, f can be expressed by the following expression. 1 / a + 1 / b = 1 / f Equation (2) Therefore, from the above Equations (1) and (2), the focal length f can be expressed by the following equation. f = ma / (m + 1) Equation (3) From Equation (1), the height AB of the main subject for which the angle of view is desired to be constant and the image height A'corresponding to the main subject on the image sensor are given.
The focal length f of the zoom lens can be obtained by calculating the image magnification m from B'and substituting the image magnification m and the distance a from the zoom lens to the main subject in the expression (3). When the distance a from the zoom lens to the main subject is changed while keeping the image magnification m constant, the focal length f of the zoom lens changes substantially linearly as shown in FIG. It should be noted that A, B, and C shown in FIG. 4 show characteristics concerning the heights of different main subjects. The height of the main subject is A <B <C.

By the way, generally, in a camera for TV shooting or movie shooting, there is a complicated relationship as shown in FIG. 5 between the operation rotation angle of the zoom ring of the zoom lens and the focal length of the zoom lens. Further, there is also a complicated relationship as shown in FIG. 6 between the operation rotation angle of the focus ring of the zoom lens and the shooting distance (distance from the zoom lens to the main subject). Therefore, if the zoom ring and the focus ring are controlled based on the focal length and the shooting distance, the processing becomes complicated. Therefore, in the present embodiment, for example, by using rehearsal shooting or the like, a table indicating the relationship between the moving distance from the shooting start position of the dolly, the rotation angle of the focus ring, and the rotation angle of the zoom ring is stored in advance in the memory 4 I remember it. The zoom ring and the focus ring are directly controlled based on the rotation angles of the focus ring and the zoom ring stored in the memory 4. The operation of writing various information to the memory 4 will be described later.

The CPU 5 centrally controls the apparatus of this embodiment. Specifically, when the memory / dolly back changeover switch (M / S switch) 10 is connected to the M side, the movement distance from the photographic start position of the dolly and the focus are measured at predetermined time intervals according to the procedure described later. The rotation angles of the ring and the zoom ring are associated with each other and written in the memory 4. When the M / S switch 10 is connected to the S side, focusing and zooming during dollyback shooting are automatically controlled according to the procedure described later. In FIG. 1, a start / end position memory switch (S / E switch) 11 is a position (rotation angle) of the focus ring and the zoom ring at the start and end of writing when writing the above-mentioned information to the memory 4. ) Is a switch for writing to the memory 4. The TELE / WIDE direction selection switch (T / W switch) 12 is a switch for selecting the direction in which the zoom ring is moved when performing dollyback.

The focus motor control circuit 6 includes a CPU 5
Of the focus ring position detection circuit 2 based on the focus control signal generated from the D / A conversion circuit 9.
With reference to the focus ring position signal from, the focus motor 13 that drives the focus ring to rotate is controlled. The zoom motor control circuit 7 is issued from the CPU 5, and the D / A
Based on the zoom control signal obtained via the conversion circuit 9,
The zoom ring position signal from the zoom ring position detection circuit 3 is referenced to control the zoom motor 14 that rotationally drives the zoom ring.

Next, the operation of the present embodiment will be described.

First, the operation of writing the above-mentioned information into the memory 4 will be described with reference to FIG. FIG.
In the above, the memory operation procedure is an operation that the photographer or the like should perform.

First, the photographer or the like puts the dolly on which the camera using the apparatus of this embodiment is placed at the position where the dolly-back photographing is started (step 1), and manually operates the zoom ring and the focus ring. The angle of view and focus of the subject are adjusted (step 2). Next, the M / S switch 10 is connected to the M side (step 3), and then the S / E switch 11 is turned on (step 4). This allows the CPU
Reference numeral 5 indicates the rotation angle of the focus ring and the zoom ring detected by the focus ring position detection circuit 2 and the zoom ring position detection circuit 3 at the dolly back shooting start position, and the movement distance (in this case, The moving distance is 0) and it is written in the memory 4 (step 11).

Next, the photographer or the like moves the dolly to a position where the dolly-back photographing is finished while keeping the photographing direction constant (step 5). At this time, the photographer or the like manually operates the zoom ring and the focus ring to perform zooming and focusing so that the angle of view of the main subject is kept constant and the main subject is focused. This operation is usually performed as follows. First, the zoom ring is moved to adjust the focal length to keep the angle of view constant, and then the focus ring is moved to adjust the shooting distance to focus on the main subject. Next, in order to correct the change in magnification caused by the adjustment of the shooting distance, the zoom ring is moved again to adjust the focal length. The above operation is repeated until the dolly reaches the position where the dolly-back shooting ends (step 6). The operation of moving the zoom ring again to adjust the focal length is performed to correct the change in the angle of view caused by the operation of the focus ring after the end of the focus ring operation. This operation is necessary especially in a small-sized and high-magnification camera. This is because, if a small-sized and high-magnification camera is configured without this operation, the following problems occur.

It is necessary to minimize the fluctuation of the pupil position, and basically, the convex structure is made to be the concavo-convex structure. Therefore, the number of lenses increases and the thickness also increases.

In the case of a high magnification zoom, not only is it difficult to maintain the optical properties, but also the performance at the TELE end (MT
F) may be worse.

On the other hand, the CPU 5 calculates the movement distance of the dolly from the shooting start position based on the signal sent from the dolly position detection circuit 1 at predetermined time intervals, and at the same time, the focus ring position detection circuit 2 and the zoom ring. The rotation angles of the focus ring and zoom ring detected by the position detection circuit 3 are acquired. Then, the rotation angles of the focus ring and the zoom ring are written in the memory 4 together with information about the moving distance of the corresponding dolly from the shooting start position (step 1).
2).

Next, when the photographer or the like has moved the dolly to the position where the dolly back photographing is finished, the photographer or the like turns the S / E switch 11 on again (step 7). As a result, the CPU 5 causes the dollyback shooting end position to
Along with the movement distance detected by the dolly position detection circuit 1, the rotation angles of the focus ring and zoom ring detected by the focus ring position detection circuit 2 and the zoom ring position detection circuit 3 are written in the memory 4 (step 11).

Next, the photographer turns off the M / S switch 10 (step 8). As a result, the operation of writing various information to the memory 4 is completed, and a table indicating the relationship between the movement distance of the dolly from the shooting start position, the rotation angle of the focus ring, and the rotation angle of the zoom ring is stored in the memory 4. .

Next, the automatic control operation of focusing and zooming during dolly-back shooting will be described with reference to FIG. In FIG. 3, the operation procedure is an operation that the photographer or the like should perform.

First, the photographer or the like selects the direction in which the zoom ring is to be moved when performing dollyback with the T / W switch 12 (step 21), and then places the dolly at the position where dollyback photography is to be started (step 21). 22). On the other hand, C
The PU 5 displays on the viewfinder, monitor, etc. of the camera that it is waiting for the dollyback shooting to start (step 31).

Next, the photographer or the like connects the M / S switch 10 to the S side (step 23). As a result, the dollyback shooting is automatically started. That is, when the photographer or the like moves the dolly to a position where the dolly-back shooting ends while keeping the shooting direction constant (step 24),
The CPU 5 calculates the movement distance of the dolly from the shooting start position based on the signal sent from the dolly position detection circuit 1 at predetermined time intervals. Then, the rotation angles of the zoom ring and the focus ring corresponding to this moving distance are read from the memory 4, and the control signals are supplied to the focus motor control circuit 6 and the zoom ring so that the zoom ring and the focus ring have the read rotation angles. Output to the motor control circuit 7 (step 32). The focus motor control circuit 6 is
The focus motor 13 is controlled by referring to the focus ring position signal from the focus ring position detection circuit 2 based on the control signal sent from the CPU 5. Similarly, the zoom motor control circuit 7 controls the zoom motor 14 with reference to the zoom ring position signal from the zoom ring position detection circuit 3 based on the control signal sent from the CPU 5. Thereby, the dolly-back shooting is performed under the same conditions as the dolly-back shooting when the various information is written in the memory 4.

According to this embodiment, a table showing the relationship between the movement distance of the dolly from the shooting start position, the rotation angle of the focus ring, and the rotation angle of the zoom ring is stored in advance in the memory 4. , The moving distance from the shooting start position of the dolly during the dolly-back shooting is sequentially obtained, the rotation angles of the focus ring and the zoom ring corresponding to the obtained moving distance are read from the memory 4, and the read rotation angle is set. It controls the focus ring and zoom ring. With this, the photographer or the like can perform zooming for keeping the angle of view of the main subject constant and focusing on the main subject by simply moving the dolly while keeping the shooting direction constant. It is possible to simplify the operation of the dolly-back shooting, which has been complicated in the past.

Further, according to the present embodiment, based on the signals sent from the dolly position detecting circuit 1, the focus ring position detecting circuit 2 and the zoom ring position detecting circuit 3, the dolly photographing start position is determined every predetermined time. From the photographing start position of the dolly and the rotation angle of the focus ring And a table showing the relationship between the rotation angle of the zoom ring and the rotation angle of the zoom ring. Thus, for example, in rehearsal shooting or the like, by writing the above various information in the memory 4, in actual shooting, simply by moving the dolly while keeping the shooting direction constant,
Zooming and focusing can be performed as in rehearsal.

Further, according to this embodiment, the memory 4 can be used without obtaining the focal length and the photographing distance of the zoom lens.
The focus ring and the zoom ring are directly controlled based on the rotation angles of the focus ring and the zoom ring stored in. Therefore, the focus ring and the zoom ring can be controlled more quickly.

The present invention is not limited to the above-described embodiments, but various modifications can be made within the scope of the gist thereof. For example, in the above embodiment, the moving distance from the dolly start position is used as the shooting distance information between the subject and the camera, but the present invention is not limited to this. For example, it may be information specifying the distance between the main subject and the camera itself, or information specifying the position of the camera with respect to the main subject. Further, although the rotation angle of the focus ring and the zoom ring is used as the information for specifying the focal length and the shooting distance of the zoom lens, the present invention is not limited to this, and the focal length and the shooting distance of the zoom lens itself. It may be information for specifying the.

Further, in the above embodiment, the automatic control of focusing and zooming in the dolly back photographing has been described, but the present invention is not limited to this, and the zooming and focusing are automatically performed by moving the dolly. Anything that does.

[0042]

As described above, according to the present invention,
With the above configuration, the photographer or the like can automatically perform zooming and focusing simply by moving the dolly on which the camera is mounted. Therefore, for example, when performing dolly-back shooting using a camera to which the device of the present invention is applied, the photographer or the like keeps the angle of view of the main subject constant only by moving the dolly while keeping the shooting direction constant. Zooming and focusing on the main subject can be performed, and thus the operation of dolly-back shooting, which has been complicated in the past, can be simplified.

According to another aspect of the present invention, distance information,
By detecting the focal length information and the shooting distance information corresponding to the distance information, and creating and storing a table showing the relationship between the distance information, the focal length information, and the shooting distance information, the shooting conditions can be set by learning once. Can be memorized.
For example, in rehearsal photography or the like, it is possible to store the relationship between the distance from the main subject to the camera, the focal length of the zoom lens, and the shooting distance. This allows
In the actual shooting, just by moving the dolly, zooming and focusing can be performed as in the rehearsal.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a zoom lens control device according to an embodiment of the present invention.

FIG. 2 is a view for explaining an operation when a table showing a relationship between information about a moving distance from a shooting start position of a dolly, information about a rotation angle of a focus ring, and information about a rotation angle of a zoom ring is stored in a memory. FIG.

FIG. 3 is a flowchart illustrating an automatic control operation of focusing and zooming during dollyback shooting.

FIG. 4 is a diagram showing a relationship between a shooting distance and a focal length of a zoom lens when a magnification of a main subject is constant.

FIG. 5 is a diagram showing a relationship between an operation rotation angle of a zoom ring of a general zoom lens and a focal length.

FIG. 6 is a diagram showing a relationship between an operation rotation angle of a focus ring of a general zoom lens and a shooting distance.

[Explanation of symbols]

 1 Dolly position detection circuit 2 Focus ring position detection circuit 3 Zoom ring position detection circuit 4 Memory 5 CPU 6 Focus motor control circuit stage 7 Zoom motor control circuit 8 A / D conversion circuit 9 D / A conversion circuit 10 M / S switch 11 S / E switch 12 T / W switch 13 Focus motor 14 Zoom motor

Claims (6)

[Claims] 1. A relationship between detection means for detecting distance information between a subject and a camera, the distance information, information specifying a focal length of a zoom lens, and information specifying a shooting distance of the zoom lens is shown. A storage unit that stores a table, and information that specifies a focal length and information that specifies a shooting distance corresponding to the distance information detected by the detection unit is read from the storage unit and specified by the read information. A control device for the zoom lens, comprising: a control unit that controls the zoom lens so that the focal length and the shooting distance are set. 2. The storage means is configured to keep the angle of view of the subject constant regardless of changes in the distance information.
2. The zoom lens control device according to claim 1, wherein information specifying the focal length is stored. 3. A first detecting means for detecting distance information between a subject and a camera, and each time the distance information is detected by the first detecting means, a focal length of a zoom lens corresponding to the distance information is specified. Second detecting means for detecting the information to be detected, and third detection for detecting the information specifying the shooting distance of the zoom lens corresponding to the distance information every time the distance information is detected by the first detecting means. Means, distance information detected by the first detecting means, information specifying the focal length detected by the second detecting means, and information specifying the shooting distance detected by the third detecting means A storage unit that creates and stores a table indicating a relationship, and from the storage unit, reads information that identifies a focal length and information that identifies a shooting distance corresponding to the distance information detected by the first detection unit, The reading Control apparatus for a zoom lens, characterized by comprising control means for controlling said zoom lens such that the focal length and the object distance specified by the out information, the. 4. Detecting distance information between a subject and a camera,
A focal length corresponding to the detected distance information is specified from a storage unit that stores a table showing a relationship between the distance information, information specifying the focal length of the zoom lens, and information specifying the shooting distance of the zoom lens. A method of controlling a zoom lens, comprising: reading information for specifying a shooting distance and information for specifying a shooting distance, and controlling the zoom lens so that a focal length and a shooting distance specified by the read information are obtained. 5. The storage unit stores a field angle of the subject to be constant regardless of the change of the distance information.
The zoom lens control device according to claim 4, wherein information specifying the focal length is stored. 6. The distance information between the subject and the camera, the information specifying the focal length of the zoom lens and the information specifying the shooting distance corresponding to the distance information are detected, and the distance information and the focal length are specified. A step of creating a table showing the relationship between the information and the information specifying the shooting distance, storing the table in a storage medium, detecting the distance information between the subject and the camera, and determining the focal length corresponding to the detected distance information. Reading information specifying information and information specifying a shooting distance from the storage medium, and controlling the zoom lens so that the focal length and the shooting distance specified by the read information are obtained. And how to control the zoom lens.