JPH07270668A - Lens position controller - Google Patents

Abstract

PURPOSE:To accomplish an automatic zooming operation with a rear-focus zooming lens and a TV-AF by a simple constitution and arithmetic operation by comparing a set magnification set by a magnification setting means with a photographic magnification calculated by a magnification calculating means and controlling 1st and 2nd lens groups so that the photographic magniflcation may become the set magnification. CONSTITUTION:The controller has an AZ(automatic zooming) function with an RFZ(rear-focus zooming lens) and the TV-AF. First of all, the size(magnification) X1 of an object which occupies a screen when each lens(a variator lens 101b and a focus lens 101d) is positioned after AF is calculated. Next, the size is compared with the size (magnification) X0 of the object which occupies the screen which is obtained by external setting, or which is previously specified, then, the moving direction of the variator lens 101b is decided. Then, the variator lens 101b is controlled so as to be driven in the decided direction by a prescribed quantity untill X1=X0 is satisfied, and also, the focus lens 101d is controlled so as to be driven while keeping such a lens relationship that a focused state is always obtained in accordance with the positional change of the variator lens 10b and the object distance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, in an optical device such as a video camera having a rear focus zoom lens (RFZ), always keeps the size of the object occupied in the screen constant even if the object distance changes. Auto zoom function (A
Z).

[0002]

2. Description of the Related Art Conventionally, as a general zoom lens of an optical device such as a video camera, a lens group (focus lens) for focus adjustment is used for a first group, and a lens group for zooming is used for a second group. There is a front-lens focus type zoom lens that uses a (variator lens). However, recently, in order to reduce the size and weight of the zoom lens and enable closer shooting, a rear focus type zoom lens (RFZ) that uses a lens group behind the variator lens for focusing is used. It is like this.

FIG. 11 is a block diagram of a video lens using RFZ.

Reference numeral 101 is a rear focus type zoom lens, 101a is a fixed front lens group, and 101b is a front lens group.
Is a variator lens group, 101c is a fixed lens group,
101d is a focusing (compensator) lens group. Reference numeral 102 is an image pickup device such as a CCD, 103 is an aperture meter, 104 is an aperture encoder for detecting an aperture value, for example, a Hall element output provided in the aperture meter 103 is used.

Reference numeral 105 denotes a camera processing circuit, and the Y signal is taken into the AF circuit 106. The AF circuit 106 determines whether it is in-focus or out-of-focus, and when it is out-of-focus, it is determined whether it is the front focus or the rear focus, and the degree of non-focus (TV-AF). These results are fetched by the CPU 107.

Reference numeral 108 denotes a power-on reset circuit, which is a power source O
Performs various reset operations at N hours. Reference numeral 109 denotes a zoom switch, the contents of which are transmitted to the CPU 107. Reference numeral 110 denotes a zoom motor, which is, for example, a step motor, and a drive pulse is transmitted from the CPU 107 to the zoom motor driver 111 and rotated according to the number of pulses to drive the variator lens group 101b through a transmission mechanism (not shown). It In addition, the number of drive pulses of the step motor is continuously measured by the CPU 10
It is counted within 7 and used as an absolute position encoder of the variator lens group 101b.

Reference numeral 112 denotes a focus motor, which uses a step motor like the zoom motor. A focus motor driver 113 drives the focus lens group 101d in the same manner as the variator lens group. Reference numeral 114 denotes data for driving and controlling each lens while maintaining a lens relationship in which the lens is always in focus according to the subject distance during zooming, and is stored in the ROM or the like.

The data 114 is, for example, a variator lens group 101 at an arbitrary subject distance as shown in FIG.
Focus lens group 101d that is focused on the position b
Is a positional relationship (cam locus), and holds cam loci (lens position data) for several types of subject distances.
During shooting, the zoom switch 109 is operated and the (V
1, RR1), when zooming from each lens position to the tele side, the variator lens group 101b is V1.
It is driven at a predetermined speed Vv.

At this time, V of the variator lens group 101b
The lens position V2 on the telephoto side after a predetermined time t from 1 is obtained,
The position RR2 of the focus lens group 101d with respect to V2 is obtained from the data 114, and the focus lens group 101d
Drive speed Vr

[0010]

[Equation 1] And ask.

Each lens is driven to (V2, RR2) at each speed (Vv, Vr). If the subject distance is not held in the data 114, the zoom operation is performed by interpolating from the subject distance cam locus (lens position data) held in the data 114.

For example, in the zooming operation from the respective lens positions of (V3, RR3) in FIG. 12, first of all the cam loci held, with respect to V3 at a subject distance S1 closer to (V3, RR3) and a far subject distance S2. RR3 ', RR3''
Then, the differences D ′ and D ″ of RR3 with respect to RR3 ′ and RR3 ″ are obtained. Next, the variator lens group 1b
The lens position V4 on the telephoto side after a predetermined time t is obtained from V3 of FIG.
RR4 ', RR with respect to V4 in S1 and S2 of
4 "is obtained and R is the ratio of the above-mentioned differences D'and D".
R4 is obtained, and the driving speed V of the focus lens group 101d
r is obtained from the above equation, and each lens has its own velocity (Vv, V
It is driven to (V4, RR4) in r).

The conventional auto-zoom function (AZ)
Is configured by calculating the focal length f to be taken from the subject distance R and the size x of the subject occupying the screen, and setting the zoom lens to the obtained focal length f.

On the other hand, as a simpler AZ method, in Japanese Unexamined Patent Publication No. 2-184808, in a front lens focusing type four-group zoom lens, a distance ring and a zoom ring are arranged at predetermined initial positions and then the positions thereof are set. AF is started, and the absolute position of the distance is known by counting the number of pulses on the rotary pulse board that works with the AF motor, and the number of pulses on the rotary pulse board that works with the zoom motor matches the pulse number of the AF motor. By letting A
Z is established.

FIG. 13 shows a relationship (constant magnification locus) between the number of pulses of the AF motor and the number of pulses of the zoom motor for keeping the size (f / R) of the subject imaged on the screen constant. According to this method, AZ is realized in a photographing magnification and a photographing distance range that do not cause a large f / R error even when approximated by the straight line a.

[0016]

As described above, the zoom lens of the optical device such as a video camera having the AZ function is
It is a front focus type. Also, in RFZ
Even if Z is performed, basically, similar to the front focus type, use the relationship of f = f (R, X) of the focal length f, the subject distance R, and the size X of the subject occupying the screen. become.

Therefore, the object distance R is detected by calculation or the like from the result of the distance measuring device or the absolute position detecting device of each lens unit for focus adjustment, and this is set externally or a predetermined X value. To calculate the focal length f,
It is necessary to calculate and control the position of the zoom lens group so that the focal length f is obtained.

Further, the positional relationship between the variator lens and the focus lens for keeping X of RFZ constant (constant magnification locus).
Is shown in FIG. As described above, the constant magnification locus of RFZ is a higher-order curve than the constant magnification locus of the front-lens focus type shown in FIG.

That is, in order to form the AZ with the RFZ, the subject distance R is obtained from the zoom lens position, and the target zoom lens position is obtained from the subject distance R and the size X of the subject in the target screen. Requires a complicated configuration or calculation. The above-mentioned simple AZ method of interlocking the variator lens with the position of the focus lens by omitting it requires complicated mechanical or electrical interlocking because the constant magnification locus becomes a high-order curve in RFZ. There is a problem.

Although it is ideal for a video camera to be able to always perform in-focus shooting, as described above, each lens position that gives a predetermined X is obtained, and the lens is driven linearly at that lens position. In this case, the maximum driving speed of each lens driving motor cannot be instantaneously driven, and a predetermined X
There is a problem that the subject is out of focus until each lens position where

[0021]

A first lens unit for zooming, and a second lens unit behind the first lens unit for correcting and focusing during zooming. First position detecting means for detecting the position of the first lens group, and second
Second position detecting means for detecting the position of the second lens group, first control means for the focusing operation, and focusing of the second lens group with the movement of the first lens group. In the lens position control device provided with the second control means for maintaining the above, the magnification setting means for setting the size of the subject occupying the screen and the detection results of the first and second position detecting means Magnification calculation means for calculating the size of the object to occupy, and magnification calculation means for calculating the size of the object to occupy the screen from the first lens group position and the second lens group position. After the focusing operation by the control unit No. 1 is completed, the set magnification set by the magnification setting unit and the photographing magnification calculated by the magnification calculation unit are compared, and the second control unit sets the photographing magnification to the set magnification. First , Providing the third control means for controlling the second lens group.

In the third control means, the first lens group is driven by a predetermined amount. Alternatively,
The first lens group is driven by an amount based on the ratio of the set magnification and the photographing magnification. Alternatively, the first
The lens group is driven at a predetermined speed. Alternatively, by driving the first lens group at a speed based on the ratio of the set magnification and the photographing magnification, each lens position that becomes the set magnification can be simply and easily kept in focus. It was done.

[0023]

【Example】

[First Embodiment] A first embodiment of the present invention will be described with reference to FIGS.

In this embodiment, AZ in RFZ and TV-AF is used.
And each lens position after AF (variator lens,
The size (magnification) X1 of the subject occupying the screen with the focus lens) is calculated and compared with the externally set or predetermined size (magnification) X0 of the subject occupying the screen to determine the moving direction of the variator lens. In this direction, the variator lens is controlled by a predetermined amount until X1 = X0, and the focus lens is drive-controlled while maintaining a lens relationship in which the variator lens position change is always in focus according to the subject distance. Is.

FIG. 1 shows a flowchart of the AF system relating to the AZ operation in this embodiment. The AF system consists of three loops. First, the loop 1 is a transition between the out-of-focus operation and the in-focus operation, and when it is determined to be out of focus in ST4, the loop 2 transitions to the out-of-focus operation. In loop 2, AF operation is first performed (ST
1).

The AF operation ST1 is, for example, an operation of detecting a focus level associated with a large number of high frequency components of a video signal, and drivingly controlling the focus lens group to a higher focus level. After ST1, the focus level after the movement of the focus lens group is compared with a predetermined focus level to determine whether or not the focus is achieved (ST2).

If it is out of focus in ST2, the operation returns to the AF operation (ST1) again, and if it is in focus, the loop 3 moves to the focus operation. In the loop 3, first, the AF operation is stopped (ST3), the focusing level is detected at a predetermined time interval, and it is determined whether or not the focusing is achieved (ST4).

If it is in focus in ST4, the AZ of the present invention
Perform operation (ST5) and return to ST4. If out of focus, A
The Z operation is stopped (ST6), and the operation again shifts to the non-focusing operation of loop 2.

The AZ operation in ST5 will be described with reference to the AZ operation flowchart shown in FIG.

First, it is determined whether or not it is in the AZ operation mode (ST5-1). The ON / OFF operation of the AZ operation mode is linked to the ON / OFF of an AZ switch (not shown), for example. Alternatively, the zoom switch (not shown) may be turned on after a predetermined time has elapsed after the zoom operation. At the same time as this AZ operation mode 0N, AZ
The set.flg, which indicates whether or not the set shooting magnification Xs for the operation is set, is cleared to 0.

In ST5-1, the AZ operation mode is OF
If it is F, the process returns to ST4. AZ operation mode is O
If N, it is determined by set.flg whether or not the set photographing magnification Xs is set (ST5-2).

If set.flg = 0 (no setting), the photographing magnification X1 is obtained by the above-described photographing magnification calculation method, the set photographing magnification is set to Xs = X1 (ST5-3), and the process proceeds to ST5-4.
If set.flg = 1 (with setting), the process proceeds to ST5-5.

At ST5-4, the flag AZ.flg for recognizing the AZ operation state is cleared to 0. AZ.flg is a flag indicating whether or not the shooting magnification X matches the set shooting magnification Xs, and if 0, X1 = Xs, and if 1, X1 ≠ Xs. In ST5-5, the AF operation status is A
Judge by F.flg.

Here, AF.flg is after the above-mentioned AF operation is completed (S
T2) Set AF.flg = 1. AF.flg = 1 if A
Since it is just after the F operation (except immediately after setting the photographing magnification), AF.flg is cleared (ST5-6), and the AZ lens operation of ST5-7 is performed regardless of AZ.flg. Also, AF.flg
If = 0, the presence or absence of the AZ operation is determined based on AZ.flg (ST5-8).

If AZ.flg = 1 in ST5-8, S
Perform AZ lens operation of T5-7, and if AZ.flg = 0, return to ST4.

The AZ lens operation in ST5-7 will be described with reference to the AZ lens operation flowchart shown in FIG.

First, the photographing magnification X1 is obtained from the variator lens position V and the focus lens position R (ST5-7-
1).

Next, X obtained in ST5-7-1 is compared with the set photographing magnification X0 (ST5-7-2). X1 = Xs
If so, AZ.flg = 0 is set (ST5-7-3), and the process returns to ST4. If X1> Xs, first the variator
The lens target position is determined to be a position (V-ΔV) moved by ΔV to the Wide side (ST5-7-6) (here, the Wide end position of the variator lens is 0 and the Tel direction is positive).

Next, as described above, the focus lens target position R (V + ΔV) is obtained from the cam locus data 114 and the variator lens target position (V-ΔV) (ST5-7).
-5).

Finally, each lens is driven to the obtained target position (ST5-7-6). After moving, set AZ.flg = 1 (ST5
-7-7), and returns to ST4 described above. If X <Xs,
First, the variator lens target position is obtained as a position (V + ΔV) moved by ΔV to the Tel side (ST5-7-
8). Next, similarly to ST5-7-5, the focus lens target position R (V + ΔV) is obtained (ST5-7-9).

Finally, each lens is driven to the obtained target position (ST5-7-10). After moving, set AZ.flg = 1 (ST
5-7-7), and returns to ST4 described above.

The AZ operation can be performed by repeating the above operation. An example of this AZ operation will be described with reference to FIG.

The solid line in FIG. 4A shows an arbitrary constant magnification locus, and the chain line shows a cam locus at each subject distance. Figure 4
4B is an enlarged view of the portion W in FIG. 4A. The solid line L1 is an arbitrary constant magnification locus, and the solid lines L2 and L3 are focusing allowable ranges for the constant magnification locus L1.

Now, suppose that the position of the zoom lens is at the point Z0 after the AF operation and the AZ operation is turned on. Here, the shooting magnification Xs is the zoom lens position Z0 as described above.
It is requested and set by. When the subject approaches a position where the subject is out of focus from this state, the AF operation is activated (loop 1 in FIG. 1), and the AF operation is performed (loop 2 in FIG. 1).

As a result, the zoom lens position becomes the point Z1, and the magnification X1 at the point Z1 is obtained for the AZ operation. Next, the magnification X1 and the set magnification Xs are compared, and in this case X
1> Xs, and the zoom lens moves on the above-described cam locus toward the wide side by a predetermined amount.

After that, the AF operation and the AZ operation are similarly repeated, and Z2, Z3, Z4, ...
・ Zn and the zoom lens operate to perform constant magnification shooting.

As described above, in the first embodiment, the AZ operation in RFZ and TV-AF can be performed with a simple structure and calculation.

Further, during the AZ operation, it is possible to always perform in-focus shooting.

[Second Embodiment] A second embodiment of the present invention will be described with reference to FIGS. 5 and 6.

The second embodiment is the AZ for RFZ and TV-AF as in the first embodiment, and the size of the subject occupying the screen at each lens position (variator lens, focus lens) after AF. (Magnification) X1 is calculated and compared with the size (magnification) X0 of the subject occupying the externally set or predetermined screen to determine the moving direction of the variator lens, and the variator lens is also focused in that direction. The lens is driven and controlled while maintaining a lens relationship in which the lens is always in focus according to the subject distance with respect to the variator-lens position change. Further, during the AZ operation, the photographing magnification X1
The moving amount of the variator lens is determined according to the ratio of the set magnification Xs.

The flow chart of the AF system relating to the AZ operation and the flow chart of the AZ operation in the second embodiment are the same as those in the first embodiment and will not be described here.

AZ lens operation of the second embodiment (ST-5
-7) will be described with reference to the AZ lens operation flowchart shown in FIG. In FIG. 5, the same parts as those in FIG.

In ST-5-7-2, if X1 = Xs, AZ.flg = 0 is set (ST5-7-3), and the above-mentioned S is executed.
Return to T4. If X1> Xs, the ratio X1 / Xs of the shooting magnification X1 and the set magnification Xs is obtained, and the variator lens movement amount Ap is obtained as Ap = kp × (X1 / Xs) using a predetermined coefficient kp (ST-7- 21).

Next, the target position obtained by moving the variator lens position to the Wide side by Ap is obtained as (V-Ap) (ST5-7-22). Next, as described above, the focus lens target position R (V + ΔV) is obtained from the cam locus data 114 and the variator lens target position (V-Ap) (ST5-7-23). Finally, each lens is driven to the obtained target position (ST5-7-6).

After the movement, set AZ.flg = 1 (ST5-7-
7) and returns to ST4 described above. In ST-5-7-2, if X1 <Xs, the set magnification Xs and the photographing magnification X1
Of the variator lens is calculated as Ap = kp * (Xs / X1) using a predetermined coefficient kp (ST5-7-24).

Next, the target position obtained by moving the variator lens position to the Tel side by Ap is obtained as (V + Ap) (S).
T5-7-25). Next, as described above, cam locus data 1
14 and the variator lens target position (V + Ap) to obtain the focus lens target position R (V + ΔV) (ST
5-7-26). Finally, each lens is driven to the obtained target position (ST5-7-10). After moving, AZ.flg = 1 is set (ST5-7-7), and the process returns to ST4.

The AZ operation can be performed by repeating the above operation. An example of this AZ operation will be described with reference to FIG.

The solid line in FIG. 6A indicates an arbitrary constant magnification locus, and the chain line indicates a cam locus for each subject distance. Figure 6
6B is an enlarged view of the portion W in FIG. 6A. The solid line L1 is an arbitrary constant magnification locus, and the solid lines L2 and L3 are focusing allowable ranges for the constant magnification locus L1.

Now, suppose that the position of the zoom lens is at the point Z0 after the AF operation and the AZ operation is turned on. Here, the shooting magnification Xs is the zoom lens position Z0 as described above.
It is requested and set by. When the subject approaches a position where the subject is out of focus from this state, the AF operation is activated (loop 1 in FIG. 1), and the AF operation is performed (loop 2 in FIG. 1).

As a result, the zoom lens position becomes the point Z1, and the magnification X1 at the point Z1 is obtained for the AZ operation. Next, the magnification X1 and the set magnification Xs are compared, and in this case X
1> Xs, the zoom lens moves to the wide side on the above-mentioned cam locus, and the photographing magnification X1 approaches the set magnification Xs.

At this time, as described above, the photographing magnification X1
Since the moving amount of the variator lens is determined according to the ratio of the set magnification Xs, the moving amount is large when the ratio is large, and the moving amount is small when the ratio is small, and the set magnification Xs can be approached more quickly. After that, the AF operation and the AZ operation are repeated in the same manner, and the Z
2, Z3, Z4, ..., Zn Zoom lens works,
Perform constant magnification photography.

As described above, in the second embodiment, the same effect as that of the first embodiment is obtained, and the movement amount of the variator lens is determined according to the ratio of the photographing magnification X1 and the set magnification Xs during the AZ operation. Therefore, the set magnification Xs can be approached more quickly.

[Third Embodiment] A third embodiment of the present invention will be described with reference to FIG.

The third embodiment is the AZ for RFZ and TV-AF as in the first embodiment, and the size of the subject occupying the screen at each lens position (variator lens, focus lens) after AF. (Magnification) X1 is calculated and compared with the size (magnification) X0 of the subject occupying the externally set or predetermined screen to determine the moving direction of the variator lens, and the variator lens is also focused in that direction. The lens is driven and controlled while maintaining a lens relationship in which the lens is always in focus according to the object distance with respect to the variator-lens position change. However, during the AZ operation, each lens is driven and controlled at a predetermined moving speed. It is the one.

The flow chart of the AF system relating to the AZ operation and the flow chart of the AZ operation in the third embodiment are the same as those in the first embodiment and will not be described here.

AZ lens operation of the third embodiment (ST-5
-7) will be described with reference to the AZ lens operation flowchart shown in FIG. In FIG. 7, the same parts as those in FIG.

The operation of the AZ lens of the third embodiment is performed at a predetermined time interval T using a timer of a microcomputer (not shown) capable of obtaining a predetermined time interval or an oscillator such as a crystal oscillator (not shown). To configure.

In ST-5-7-2, if X1 = Xs, AZ.flg = 0 is set and each lens drive is stopped (ST.
5-7-3), and returns to ST4 described above. If X1> Xs, a predetermined vater lens driving speed Vv is set (S
T5-7-31).

Next, the focus lens drive speed Vr is set (ST-5-7-34). Here, how to obtain the focus lens driving speed will be described.

First, the variator lens position after the above-described AZ lens operation cycle T is calculated as Vt = V-kv * Vv * T using the operation cycle T and the variator lens driving speed Vv. Here, kv is the ratio of the driving speed of the variator lens driving motor (not shown) to the variator lens moving speed.

Next, the cam locus data 114 as described above.
And the variator lens position Vt, the focus lens target position R (Vt) is obtained, and the focus lens drive speed Vr is calculated using the focus lens position R and the operation cycle T obtained in ST-5-7-1.

[0072]

[Equation 2] And ask. Here, kr is the ratio of the drive speed of the focus lens drive motor (not shown) and the focus lens movement speed.

Each lens is driven at each lens drive speed finally obtained (ST5-7-6). After driving, set AZ.flg = 1 (ST5-7-7) and return to ST4. ST-5
If X1 <Xs in 7-2, a predetermined vater lens driving speed Vv is set (ST5-7-33).

Next, the focus lens drive speed Vr is set (ST-5-7-34). Here, how to obtain the focus lens driving speed will be described. Basically ST5-7-
However, the driving direction is different from ST-5-7-32, and the variator lens position after the AZ lens operation cycle T is calculated using the operation cycle T and the variator lens drive speed Vv as follows: Vt = V + kv × Vv × T

Next, similarly, the focus lens target position R (Vt) is obtained, and the focus lens drive speed Vr is obtained. Each lens is driven at each lens driving speed finally obtained (ST5-7-10). After driving, set AZ.flg = 1 (ST5-7-7) and return to ST4.

The AZ operation can be performed by repeating the above operation.

As described above, in the third embodiment, the same effect as that of the first embodiment is obtained, and since each lens is controlled to be driven at a predetermined moving speed during the AZ operation, the lens is stopped during the AZ operation. Will be less. Therefore, it is possible to more smoothly approach the set magnification Xs while changing the angle of view.

[Fourth Embodiment] A fourth embodiment of the present invention will be described with reference to FIG.

The fourth embodiment is the AZ for RFZ and TV-AF as in the third embodiment, and the size of the object occupying the screen at each lens position (variator lens, focus lens) after AF. (Magnification) X1 is calculated, and the moving direction of the variator lens is determined by comparing it with the size (magnification) X0 of the object occupying the screen set externally or in advance, and the variator lens is moved in that direction at a predetermined speed. Also, the focus lens is drive-controlled at a speed that maintains a lens relationship in which the focus lens is always in focus according to the subject distance with respect to the variator lens position change, but during the AZ operation, the shooting magnification X1 is set. The driving speed of the variator lens is determined according to the ratio of the magnification Xs.

The flow chart of the AF system relating to the AZ operation and the flow chart of the AZ operation in the fourth embodiment are the same as those in the first embodiment and will not be described here.

AZ lens operation of the fourth embodiment (ST-5
-7) will be described using the AZ lens operation flowchart shown in FIG. In FIG. 8, the same parts as those in FIG.

The operation of the AZ lens of the fourth embodiment is configured to operate at a predetermined time interval T as in the third embodiment.

In ST-5-7-2, if X1 = Xs, AZ.flg = 0 is set and each lens drive is stopped (ST.
5-7-3), and returns to ST4 described above. If X1> Xs, the ratio X1 / Xs of the photographing magnification X1 and the set magnification Xs is calculated, and the variator lens driving speed A is calculated using a predetermined coefficient kv.
v is calculated as Av = kv × (X1 / Xs) (ST-7-41), and the vaeter lens driving speed V
v is set (ST5-7-44).

Next, the focus lens drive speed Vr is set to the third value.
Obtained in the same manner as in Example ST-5-7-32 (ST5
-7-43). Each lens is driven at the obtained lens driving speed (ST5-7-6). After driving, set AZ.flg = 1 (S
(T5-7-7), and returns to ST4 described above.

If X1 <Xs in ST-5-7-2, the ratio Xs / X1 of the photographing magnification X1 and the set magnification Xs is obtained, and the variator lens driving speed Av is Av = kv × using a predetermined coefficient kv. (Xs / X1) is obtained (ST-7-44), and the baeta lens drive speed V is obtained.
v is set (ST5-7-45).

Next, the focus lens drive speed Vr is set to the third value.
Obtained in the same manner as in Example ST-5-7-34 (ST5
-7-46). Each lens is driven at the obtained lens driving speed (ST5-7-10). After driving, set AZ.flg = 1 (ST5-7-7) and return to ST4.

The AZ operation can be performed by repeating the above operation.

As described above, in the fourth embodiment, the same effect as that of the third embodiment is obtained, and the driving speed of the variator lens is determined according to the ratio of the photographing magnification X1 and the set magnification Xs during the AZ operation. Therefore, the set magnification Xs can be approached more quickly.

[Fifth Embodiment] The fifth embodiment uses the same RFZ and AZ for TV-AF as in the first embodiment.
In the shooting magnification calculation of T5-7-2, several kinds of constant magnification trajectory data are held in advance in the ROM or the like, and the constant magnification trajectory data is used to determine the shooting magnification at any variator lens position and focus lens position. This is obtained by interpolation.

FIG. 9 shows a block diagram of the video lens of the present invention. In the figure, those having the same symbols as those in FIG. 11 are the same and will not be described.

Reference numeral 1 denotes several kinds of constant magnification locus data, for example, the position V of the variator lens group 101b and the position of the focus lens group 101d of the object size X occupying an arbitrary screen as shown in FIG. It is a relationship of R (constant magnification locus), and a constant magnification locus for several kinds of X is expressed as R = ΣKn * Rn (V, X) (Equation 5-1). V, X) is approximated and the coefficient Kn is held in a memory means such as a ROM.

Next, a method of calculating the photographing magnification X at each lens position using the constant magnification locus data will be described. The position V of the variator lens group 101b and the position R of the focus lens group 101d are shown in FIG.
1, R1).

First, the focus lens group position with respect to the variator lens group position V1 at each magnification held in the data 1 is obtained by using the data 1 (Equation 5-1), and R1 is the focus lens position of which magnification. Then, the obtained magnification and focus lens position are set to (X2, R2) and (X3, R3). Next, the differences D2 and D3 between R1 and R2 and R3 are obtained.

Then, the photographing magnification X1 at the lens position (V1, R1) is determined by the ratio of D2 and D3.

[0095]

[Equation 3] And ask. With this method, the photographing magnification X at each lens position can be obtained without performing a complicated calculation.

Since the AZ operation and the AF operation related to the AZ operation are the same as those in the first embodiment, the description thereof will be omitted. The AZ operation of the second to fourth embodiments may be the AZ operation of the fifth embodiment.

As described above, in the fifth embodiment, complicated calculation of the subject distance R, the focal length f, etc. is omitted, and the photographing magnification is easily obtained from each lens position and several kinds of constant magnification locus data held in advance. Therefore, the AZ operation can be configured more easily.

[0098]

As described above, the AZ operation in RFZ and TV-AF can be performed with a simple configuration and calculation.

Further, during the AZ operation, it is possible to always perform in-focus shooting.

[Brief description of drawings]

FIG. 1 is a flowchart of an AF system related to AZ operation.

FIG. 2 AZ operation flowchart

FIG. 3 is a flowchart of an AZ lens operation according to the first example.

FIG. 4 is a diagram showing changes in the position of each lens due to the AZ operation in the first embodiment.

FIG. 5 is an AZ lens operation flowchart of the second embodiment.

FIG. 6 is a diagram showing changes in the position of each lens due to the AZ operation in the second embodiment.

FIG. 7 is an AZ lens operation flowchart of the third embodiment.

FIG. 8 is an AZ lens operation flowchart of the fourth embodiment.

FIG. 9 is a configuration diagram of a video lens of Example 5

FIG. 10: Constant magnification locus diagram in RFZ

FIG. 11 is a block diagram of a conventional video lens using RFZ.

FIG. 12 is a cam locus diagram of RFZ.

[Fig. 13] Constant magnification locus of front focus type

FIG. 14 is a constant magnification locus diagram of RFZ.

[Explanation of symbols]

 1 Constant magnification locus data 101 Zoom lens 102 Image sensor 103 Aperture 104 Encoder 105 Camera processing circuit 106 AF circuit 107 CPU 108 Power-on reset 109 Zoom switch 110 Zoom motor 111 Zoom motor driver 112 Focus motor 113 Farcus motor driver

Claims (7)

[Claims] 1. A first lens group for zooming, and the first lens group.
Second lens group for performing the correction and focusing operations when zooming behind the second lens group, first position detecting means for detecting the position of the first lens group, and second lens group Position detecting means for detecting the position of the second lens group, the first control means for the focusing operation, and the in-focus state of the second lens group with the movement of the first lens group. In a lens position control device provided with a second control means, a magnification setting means for setting a size of an object occupying a screen, and a size of the object occupying the screen from detection results of the first and second position detecting means. And a magnification calculation means for calculating the height, and after completion of the focusing operation by the first control means,
The setting magnification set by the magnification setting means is compared with the photographing magnification calculated by the magnification calculating means, and the second controlling means causes the photographing magnification to become the setting magnification.
A lens position control device comprising third control means for controlling the second lens group. 2. A first lens group for zooming, and the first lens group.
Second lens group for performing the correction and focusing operations when zooming behind the second lens group, first position detecting means for detecting the position of the first lens group, and second lens group Position detecting means for detecting the position of the second lens group, the first control means for the focusing operation, and the in-focus state of the second lens group with the movement of the first lens group. In a lens position control device provided with a second control means, a magnification setting means for setting the size of a subject occupying the screen, a first lens group position and a first lens group position where the size of the subject occupying the screen is substantially constant. A memory means for storing data relating to the positional relationship between the two lens groups, a magnification calculation for calculating the size of the object occupying the screen based on the detection results of the first and second position detecting means and the data read from the memory means. Means for providing the first After the focusing operation by the control means is completed, the set magnification set by the magnification setting means and the photographing magnification calculated by the magnification calculating means are compared, and the second controlling means sets the photographing magnification to the set magnification. A lens position control device comprising third control means for controlling the first and second lens groups. 3. The lens position according to claim 1, wherein the second control means includes a storage means for storing positional relationship information of the first and second lens groups for maintaining a focused state. Control device. 4. The lens position control device according to claim 1, wherein the third control means drives the first lens group by a predetermined amount. 5. The lens position control device according to claim 1, wherein the third control unit drives the first lens group by an amount based on the ratio of the set magnification and the photographing magnification. 6. The lens position control device according to claim 1, wherein the third control means drives the first lens group at a predetermined speed. 7. The lens position control device according to claim 1, wherein the third control unit drives the first lens group at a speed based on a ratio between the set magnification and the photographing magnification.