JP3523658B2 - camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera, and more particularly to a camera.
Focus in zooming operation of the zoom lens.
Move the focus lens to the correct position, so-called zoom
The present invention relates to a camera that performs a tracking operation. [0002] 2. Description of the Related Art Conventionally, in a video camera or the like,
During zooming operation of the zoom lens, the zoom track
In many cases, a switching operation is performed. FIG. 6 shows the zoom tiger.
Focusing on zoom lens position during
Diagram showing the change of the focus lens position that becomes the normal position
It is. The tracking operation is performed at each zoom lens position.
On the other hand, the focus lens is moved along the curve of FIG.
It is performed by moving. FIG. 7 shows a general photographing device such as a video camera.
FIG. 3 is a diagram showing a conceptual diagram of a shadow optical system, and
The object image is captured by an imaging surface of a CCD 52 through a photographing lens 51.
It shall image on top. As shown in the figure,
And the front focal position FF and the rear focal position FB
The distance from the imaging surface of the CCD 52 to the
The distance between the point positions FB is D. Further, in front of the subject 50
Assuming that the subject distance between the square focal positions FF is L, this optical system
At L × D = -f^Two    ............ (1) Is established. Note that the subject in the above equation (1)
The distance L is usually indicated by the distance from the lens tip.
Originally, the value of L + f must be used.
The point distance f is generally about 50 mm,
Since the distance L can be ignored, the value L + f
Has been substituted. FIG. 8 shows a zoom track in the optical system.
This is a diagram showing a part of the king curve.
Indicates the change of the focus lens extension position
ing. The focal lengths f1 and f2 of the photographing lens 51 are
Focusing position at the object distance ∞ (infinity)
With respect to the positions P0, Q0 and the subject distance L11.
Position P1, Q2, position P2, Q2 with respect to subject distance L12.
And Further, at the object distance ∞ at the focal length f1,
Focus based on focusing position P0
The lens extension amounts are D11 and D12. Also the focal length
Focusing position Q0 at subject distance に お け る at f2
The extension of the focus lens based on
1, D22. The above equation (1) is applied to each of the above positions.
When fitted, L11 × D11 = -f1^Two      ............ (2) L12 × D12 = -f1^Two      ……………… (3) L11 × D21 = -f2^Two      ……………… (4) L12 × D22 = -f2^Two      ............ (5) And from equations (2) and (3) L11 × D11 = L12 × D12 (6) Also, from equations (4) and (5) L11 × D21 = L12 × D22 (7) Holds. Furthermore, whether equations (6) and (7) hold
Et al., D22 / D12 = D21 / D11 (8) It becomes. [0006] Since the above equation (8) holds, the reference
A tracking curve for a distance な る that is the object distance,
In addition, the reference focus at a predetermined subject distance, for example, L11.
Focus lens extension amount D21 at point distance f2
Of the focus lens at other focal lengths f1
The value of the ratio D21 / D11 to D11 (hereinafter, this focus lens
(The ratio of the feed amount is referred to as the feed ratio).
If given, indicates the required extension position of each zoom lens.
The zoom tracking curve as shown in FIG.
According to the curve, the focus during the zoom operation is obtained.
The lens can be extended to an appropriate in-focus position. [0007] The zoom tracking curve shown in FIG.
Conventionally, various zoom tracking control methods
Has been proposed. For example, "NATIONAL TECHNIC
AL REPORT ”(VOL. 37 NO.3 JUN. 1991, pp. 338-344)
  Zoom lens zoom of the video camera described in
The zoom tracking method uses the zoom track stored in the memory.
Read the table of the curve and interpolate the table
To calculate the appropriate amount of movement of the focus lens
And perform tracking. [0008] Zoom tracking by the above table interpolation
9 will be described in detail.
Reference subject distance L1 of zoom tracking curve
(= ∞) and subject distance L2, and between distance L1 and L2
Tracking curve for subject distance L3
It is the diagram which extracted and shown. At the zooming position Za
Focus lens for subject distances L1 and L2
The positions are A1 and A2, and the position at the zooming position Zb is
The focus lens position for the object distances L1 and L2 is B
1, B2. Then, the delivery at the positions A2 and B2
The amount is set to values Db and Dd as shown. Note that these
Is stored in the memory. Now, the zoom lens is located at the position Za,
Move to the position A3 on the tracking curve with the object distance L3.
It is assumed that a focus lens is located. The position A3 is
, The focus lens position A1 with respect to the zoom position Za,
A2 and the focus lens position based on A2
Defined relatively from the feeding amount Da by A1 and A3
be able to. Therefore, the zoom lens position changes to Zb
Suppose you did. The subject distance L1 at the zoom position Zb,
L2 focus lens positions B1, B2 and repetition between two points
The delivery amount Dd is obtained from the memory storage information. Subject distance
The tracking curve of the separation L3 is equal to the above-mentioned payout ratio Da /
Assuming that Db is maintained, the position B1
Relative position B3 is obtained, and the feeding amount Dc
Is required. The calculation by the table interpolation is performed by a certain
Two tracking cars sandwiching a rocking curve
Is assumed to be interpolated at a certain ratio
You. Therefore, it is stored in memory to maintain the accuracy of interpolation.
It is necessary to set the number of tracking curves
As an example, eight tracking curves are used as data.
Video cameras for storing have been proposed. Note that this
As a proposal other than a video camera, "MITSUBISHI ELE
CTRIC ADVANCE ”(DEC. 1991, pp. 32-33)
Mera uses 12 tracking curves as data
I remember. [0011] However, the above equation
An equation indicating that the payout ratio of (8) is constant holds.
This is because the light incident on the focus lens is parallel light.
Since it holds only for a range closer to the phototype,
Move away from the distance where the light incident on the focus lens is parallel
The more the feeding ratio becomes, the more the payout ratio is not constant. For example,
As shown in the payout ratio in Table 1 below, the focal length is 5.
It changes greatly based on the 15 mm payout ratio.
In addition, the amount of change varies depending on the subject distance.
Also, a lens system having a tracking curve shown in FIG.
According to the simulation, the maximum feed position of 200μm
Misalignment occurred. Note that this lens has an error of 30 μm.
If there is, it feels out of focus. Also, during zoom operation
Under conditions where it is relatively difficult to feel out-of-focus
However, in practice, only a deviation of 50 μm can be tolerated. Therefore, the aforementioned "NATIONAL TECHNICAL REP"
ORT ”(VOL. 37 NO.3 JUN. 1991, pp. 338-344)
The above conditions are considered when considering the
In order to satisfy
Assuming that the curve data is stored in the memory, the focal length
64 steps and focus lens position 8
If the accuracy shown in the 64 bytes x 10 lines = 640 bytes Requires a large storage capacity for a general video camera.
Will be required. [0013] In addition, the
For video cameras with a camera ratio of 10 times or more,
However, for accuracy, 64 steps to 256 steps (8 bits
), The memory capacity must be 2.5K
You need something for the site. Such memory capacity
In terms of volume, it is realistic for a consumer video camera
I can't say. The present invention has been made in order to solve the above-mentioned problems.
Focus on zoom tracking accuracy
Need to increase memory capacity
Without using a simple configuration, zoom tracking control is performed.
It is an object of the present invention to provide a camera capable of performing the operation. [0015] Means for Solving the Problems The present inventionbyThe camera is
ZReference object distance when moving within a predetermined range of the zoom lens
This is the locus of the appropriate position of the focus lens corresponding to the separation.
To hold data representing the zoom tracking curve
Reference zoom tracking curve data holding means,No.
First group numerical data to hold one group of numerical data
Holding means,No.No. 2 for holding two sets of numerical data
Means for holding two groups of numerical data;the aboveThe zoom lens is
When in the first position corresponding to the reference zoom magnificationOf
Corresponding to the object distancethe aboveThe proper position of the focus lens
Derived from the data representing the zoom tracking curve
AboveCompatible with reference subject distancethe aboveFocus lens
Expressed as the distance between the appropriate position andthe aboveFour
The reference feeding amount of the lens is set as the first feeding amount,
The zoom lens has a second position different from the first position;
When in positionRecordFocus corresponding to object distance
The proper position of the lensThe above zoom tracking curve is displayed.
Derived from dataA file corresponding to the above reference subject distance
Expressed as the distance between the correct position of the focusing lens and the two positions.
The amount of extension of the focus lens to be extended to the second amount of extension
, And the first and second feeding amounts.
Feed-out ratio value expressed as the ratio of both feed-out amounts
To this second payout amountthe aboveNumerical value of the first groupIn one of
A givenMultiplied by the first constantAboveNumerical value of the second groupof
One givenAdd a second constanthandCalculateRepetitionStart
Ratio calculation means and the required focus lensSecondRepetition
AmountTo calculate, The first feed amount
Projection amountToCalculated by the above-mentioned payout ratio calculating means.
Feeding ratioDivide byWith the feeding amount calculating means.
And features. [0016] [0017] In one camera of the present invention, focus
The target extension amount of the lens is defined as the first extension amount.
The feed ratio calculated by the feed ratio calculation means
Drive the focus lens to the target position to zoom
Perform racking operation. [0018] [0019] DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings.
You. FIG. 1 is a main part of a video camera according to a first embodiment of the present invention.
It is a block block diagram. The main configuration of this camera is
The fixed lens that forms the
Of the first lens unit 1 as a lens group and the second lens unit for zooming
Lens group 2, the third lens group 3, which is a fixed lens group,
The focus lens 4 of the fourth group lens and the image of the subject 20
CCD5 for converting to an electric signal, and the imaging signal of CCD5
The video signal is converted to a video signal and output to a recording circuit (not shown).
Image circuit 6 and zoom operation in tele and wide directions
The zoom switches 12 and 13 for instructing and the zoom switches
The signals of the switches 12 and 13 are processed, and a zoom lens
Output to moving part 8 or zoom tracking control circuit 7
And a ROM and the like.
The subject distance 基準 (infinity), which is the reference subject distance.
Data holder for corresponding reference zoom tracking curve
Steps and first and second groups for determining the payout ratio
First and second storing the values VAL1, VAL2, etc.
A memory 15 containing a group numerical data holding means and the like;
Based on the signals from the zoom switches 12 and 13, the zoom
The zoom tracking control circuit for performing racking control
7 and a zoom lens based on the signal of the zoom switch.
A zoom lens driving unit 8 for driving the zoom lens 2;
The movement of zoom lens 2 is detected, and the signal is
A zoom encoder 9 input to the zoom control circuit 7;
Tracking control circuit 7 and AF control circuit 1
Drive for driving the focus lens 4 based on the output of 0
Section, which is composed of a stepping motor
Included in the video signal from the lens driver 11 and the video circuit 6
Focus detection information indicating the degree of focus that has been
The contrast information in the ascending focusing method is extracted, and the
Focus lens A with respect to focus lens drive unit 11
AF control circuit that outputs an F (autofocus) control signal
It is constituted by the road 10 and the like. The zoom tracking control circuit 7
Includes a feed-out ratio calculating means to be described later and a feed-out amount calculation.
Means are built-in. Also, the focus lens 4
The drive unit 11 moves the stepping mode
Since there is no need for detection because it is composed of
No encoder for the lens is required. Next, in the present embodiment configured as described above,
The zooming operation of the camera is for tele and wide
Executed based on operation signals of zoom switches 12 and 13
It is. That is, the signal is input to the zoom lens driving unit 8.
Then, the drive unit 8 controls the zoom lens based on the operation signal.
Drive 2 is performed. Note that the zoom encoder 9
The zoom lens 2 reaches the wide or telephoto end.
Is detected, the driving unit 8 performs the driving operation.
To stop. At the same time, the zoom switches 12 and 13
The operation signal is also input to the zoom tracking control circuit 7.
The tracking control described later is performed, and the focus
Lens 4 is advanced to the appropriate position corresponding to the zoom position.
Will be issued. The zoom tracking control circuit 7
Is always the zoom lens position from the zoom encoder 9.
Position information ZO and the focus information from the focus lens drive unit 11.
Focus lens position information FO is taken in. In addition,
In the embodiment, the third lens unit is fixed,
Focus lens 4 according to the function of zoom lens 2
It may be moved to assist. The focus of the focus lens 4 itself is
The sing operation is performed by the AF control circuit 10 from the video signal.
This is executed according to the extracted focus detection information. That is, AF
A focus lens is provided to the control circuit 10 based on the focus detection information.
4 is calculated, and the focus lens driving unit 11 is operated.
Through this, the focus lens 4 is driven to the in-focus position. Next, the zoom track of the camera of the present embodiment.
The following describes the switching control. Figure 2 shows the reference subject
The zoom track for the body distance ∞ and a certain subject distance L0
It is a diagram showing an example of a king curve. This trucking
Zoom lens 2 is in the first position
When at the reference wide end position W
The amount of extension of the focus lens 4 from the
The reference feeding amount Dk is used as the feeding amount. Soshi
The zoom position Z where the zoom lens 2 is at the second position.
Extending position corresponding to the distance 場合 when it changes from O1 to ZOn
The amount of extension of the focus lens 4 from the position
The delivery amounts D1 to Dn are the delivery amounts. The position
FO1 to FOn are the values when zoom tracking drive is performed.
3 shows the extension position of the focus lens 4. Therefore, each of the above feeding amounts D1 to Dn and
Feeding ratio Dk / D which is a ratio to the reference feeding amount Dk.
When n is measured, for example, data as shown in Table 1 is obtained.
Have been. Table 1 shows the focal length at the wide end position and
5.15 mm, and the value Dk / Dn at each focal length was calculated.
The change is shown for each subject distance. [0025] [Table 1]The value of the feed-out ratio Dk / Dn in Table 1 above depends on each focal length.
Therefore, it also changes depending on the subject distance
However, for the reciprocal (diopter) of the subject distance, 1
It has the following function. From the above equation (1), the above ∞ distance pair
The feeding amount Dk from the feeding position is
The value of the feed ratio Dk / Dn is proportional to
It can be approximated by a linear expression for the delivery amount Dn
It is. That is, the value of the feed-out ratio Dk / Dn depends on each focal length.
VAL1, which is numerical data of the first group that changes with separation
And VAL2 which is the numerical data of the second group, Dk / Dn = VAL1.times.Dn + VAL2...
…… (9) Can be shown in the form of VAL1 and VAL2 are
Lens lens position, that is, a value that varies depending on the focal length
Equation (9) is given by the following Table 2 for each focal length.
Is given as shown. [0026] [Table 2]In the camera according to the present embodiment, the V
AL1 is the first group numerical data corresponding to each zoom lens position
VAL2 is also used for each zoom lens
As the second group numerical data corresponding to the position, the memory 15
To be stored. At the time of zoom tracking control,
The above numerical data VAL1 of the corresponding zoom lens position,
And VAL2 is read out, and the output ratio Dk / Dn
The value is obtained by the equation (9). Further, in the camera of this embodiment, the reference
At each zoom lens position ZO1 to ZOn at the object distance ∞
The proper zoom, which is the reference zoom tracking curve data for
Extending position data of the focus lens 4 @DATA (ZO
n) is also stored in the memory 15. When performing zoom tracking control,
In this case, Dn0, which is the amount of extension at the beginning of the operation, and the memory 15
The stored values VAL1 and VAL2
Then, the value Dk / Dn0, which is the payout ratio at the beginning of the operation, is obtained.
You. Further, the feeding ratio Dk / Dn0 and the feeding amount Dn0
From this, the reference feeding amount Dk in the initial state is obtained. Continued
When the zoom lens position is changed, the zoom
The feeding ratio Dk / Dn with respect to the zoom lens position ZOn is
It is obtained from the value data VAL1 and VAL2,
From the feed ratio value and the reference feed amount Dk.
Of the focusing lens is calculated. Soshi
Then, the storage amount of the memory 15 is stored with respect to the feeding amount Dn.
The feeding-out position data $ DATA (ZOn)
Add and target the appropriate in-focus position of the focus lens 4
Is calculated, and the data signal is calculated by the focus lens driving unit 1.
1 to terminate the zoom tracking operation. Next, a flowchart of the zoom processing of FIG.
The zoom tracking operation of the camera of this embodiment
Will be described in more detail. Zoom switch 12,
Alternatively, when the zoom processing is started by pressing the button 13,
First, in steps S11 and S12, the initial focus
Of the zoom position FO1 and the initial zoom lens position ZO1
Is taken into the zoom tracking control circuit 7. In step S13, the initial focus
The lens position FO1 and the reference stored in the memory 15
Feed amount at subject distance (∞) ∞DATA (ZO1)
And the feed amount D1 is obtained from
From the value V corresponding to the initial zoom lens position ZO1
AL1 and VAL2 are read, and based on the above equation (9),
To determine the feeding ratio Dk / D1 with respect to the feeding amount D1.
I will. Then, in step S15, the base for the initial state is determined.
The quasi-delivery amount Dk is calculated. Note that this reference
The zoom lens position corresponding to the amount Dk is the wide end W.
You. In step S16, a zoom switch
It is assumed that the zoom lens 2 has been moved by the operations of 12, 13
The moving zoom lens position ZO2 is input. continue,
In step S17, the zoom lens position ZO2 is
The corresponding values VAL1 and VAL2 are read, and the current zoom position is read.
Feeding ratio Dk to feeding amount D2 in ZO2
/ D2. However, the left side of the operation expression of this step
Unless the feed-out amount D2 is originally used, the feed-out amount D1 must be used.
However, since the value D2 is undecided at this point,
Uses the feeding amount D1. Further, as described below
Zoom drive continues and the zoom position is updated.
Even if it is repeated, the zoom position found just before
Will be used. For this
In the case of this camera, the error is from the wide end position W to the tele end position.
Since it is divided into 64 steps up to T,
Even if the immediately preceding value is used, no large error occurs. In step S18, the payout ratio
Dk / D2 and the initial state obtained in step S15.
Lens position ZO2 from the reference feed amount Dk in the state
Is obtained as the target feeding amount D2 corresponding to the above. In addition,
In step S19, the target focus lens position FO
2 to the target extension amount D2.
Delivered amount 基準 DAT for reference subject distance 被 写 体 at O2
A (ZO2) is obtained by addition. Then, step S2
0, the data of the target focus lens position FO2 is
Output to the focus lens drive unit 7. In step S21, a zoom switch
12 and 13 are pressed and the zoom position is updated.
Is determined by the change in the output value of the zoom encoder 9.
Admit. Then, the switch is not operated and the zoom position
If this is not updated, this routine is terminated.
Has been updated, the process returns to step S16 and has been updated.
Target focus for next zoom lens position ZOn
The calculation of the lens movement position FOn is executed. However,
The suffix shown in steps S16 to S20
Fix 1 or 2 is input each time the process is repeated.
Be incremented. As described above, the video camera of this embodiment
In LA, the memory required for zoom tracking
As data, each zoom level at the reference subject distance (∞)
Lens position data corresponding to the lens position ZOn
ΔDATA (ZOn) and each zoom lens position Z
Data group VAL1 corresponding to On and data group VAL2
And so on, interpolating the conventional zoom tracking curve
Memory 1
5 has a smaller storage capacity, and has a higher accuracy.
It is possible to perform the team tracking. In the camera of the present embodiment,
The zoom distance corresponding to the reference feed amount Dk for calculating the feed ratio
Position is the wide end W, but this position is different
May be specified. Further, the focus lens 4
Data of the subject distance ∞ as a reference for the
But also at other subject distances
Applying the stitching curve as the reference data of the above feeding position
It is also possible. Next, a video camera according to a second embodiment of the present invention.
Will be described. The camera of the present embodiment has a zoom track.
The method for obtaining the target payout amount in king control is described above.
It is different from that of the first embodiment,
The basic configuration of the laser is the same as that of the first embodiment. However
The memory for tracking control is shown in FIG.
The used memory 15A is used. In the memory 15A
Corresponds to each zoom lens position at the reference subject distance (∞)
Focus lens position data ($ DATA
(ZOn) and each zoom lens at a predetermined subject distance
A group of numerical values to be described later showing the payout ratio corresponding to the close position
(KHDATA (ZOn)) and the correction coefficient hn
An arithmetic expression and the like to be described later are stored. Also, zoom tracking
As the zoom control circuit, the zoom track shown in FIG.
A control circuit 7A is used.
It has built-in ratio calculation means and correction coefficient calculation means, etc.
You. Here, the feeding ratio Dk / Dn shown in Table 1 is used.
Is repeated at a distance of 1 m, which is the predetermined object distance.
Of the ratio of the feeding ratio based on the value of the feeding ratio
When the change is obtained, the values shown in Table 3 are obtained. [0038] [Table 3]Each value in Table 3 above corresponds to the correction coefficient hn.
Thus, for example, at a focal length of 25.45 mm,
When trying to find the payout ratio at a body distance of 1.7m
In this case, from Table 3, the correction coefficient h under the condition is 0.973.
Is required. On the other hand, the reference focal length is 25.45 m
Table 1 shows the extension ratio at m and the object distance of 1 m.
4.87 × 10^-2Is required. This payout ratio
4.87 × 10^-2Is multiplied by 0.973 of the correction coefficient h.
Then, an accurate payout ratio under the above conditions is obtained. Then, the tracking of the camera of this embodiment is performed.
In the control, an operation for determining the feed ratio Dk / Dn is performed.
As an expression, the following linear expression, Dk / Dn = hn × KHDATA (ZOn) ............
............ (10) Shall apply. Where hn is the second payout
The focus lens extension amount Dn, which is the displacement amount, and the second
Linear relationship with the zoom lens position ZOn
The correction coefficient is a coefficient having. Also, KHDATA
(ZOn) is a predetermined subject distance described later, for example,
Each zoom lens position ZOn at a subject distance of 1 m
Is a group of numerical values indicating the payout ratio Dk / Dn corresponding to
You. The values of the correction coefficients hn in Table 3 are satisfied.
As a linear expression for hn = α × Dn + β ……………………………
…… (11) Is used. However, both coefficient values α and β are zoom lens positions.
Is the value corresponding to the position. In particular, the value β is approximated by
be able to. That is, β = 1.396-0.02837 × ZOn ………………
… (12) And The following Table 4 shows the correction coefficient hn of the above equation (11).
The calculation formula is shown for each zoom lens position.
is there. [0041] [Table 4]Now, as can be seen from Table 3 above, when the focal length is 17 mm or less,
Indicates that the value of the correction coefficient hn does not change much and is close to the value 1.
Can be Also, if the focal length is 25.45 mm or more,
Is that the value of the coefficient α in the equation (11) is close to 0.07.
be able to. Therefore, in the camera of this embodiment, the focal length
Zoom lens corresponding to the intermediate position between 17mm and 25.45mm
If the distance is less than 15 mm of the distance 2
The value of the positive coefficient hn is fixed to 1. In addition, the movement amount is 15 mm
If the above is the case, the value of the coefficient α is set to 0.07,
β takes the value of the above equation (12), and
The number hn equation applies. That is,     hn = 0.07.times.Dn + 1.396-0.02837.times.ZOn (13) And the payout ratio is calculated by the equation (13). In the camera of this embodiment, the tracking
The data stored in the memory 15A for power control includes
As shown in FIG. 1, each zoom at the reference subject distance (∞)
Focus lens position data corresponding to the zoom lens position ZOn.
∞DATA (ZOn), for example,
Corresponds to each zoom lens position ZOn at an object distance of 1m
KH which is a group of numerical values indicating the calculated payout ratio Dk / Dn
Equation (13) for calculating DATA (ZOn) and correction coefficient hn
Are stored. And stored in the memory 15A.
The zoom tracking control based on each data
An appropriate extension position of the focus lens 4 is required. Next, the flowchart of the zoom processing shown in FIGS.
According to the zoom tracking of the camera of the present embodiment.
The processing operation will be described in detail. Note that, in part,
The same processing as the processing of the first embodiment is also included. As shown in FIG.
The zoom switch 12 or 13 is pressed
Is started, but the processing of steps S31 to S33 is
This is the same as that of the first embodiment. In step S34, the zoom lens 2
Is detected by the zoom encoder 9 and the value is
Check if the travel distance indicating the boundary position is 15 mm or more
You. If the amount of movement is less than 15 mm, jump to step S37.
And the correction coefficient hn is fixed at a value of 1, and the movement zoom
Value corresponding to the lens position ZO1.
The value KHDATA (ZO1) read from A is
The feed ratio Dk / D1 is set as it is, and will be described later.
Proceed to step S38. In addition, when the moving amount is 15 mm or more,
If there is, the process proceeds to step S35, where
The correction coefficient h1 is obtained by performing a calculation based on the above. Change
In step S36, the correction coefficient h1 and the memory 15A
From the value KHDATA (ZO1) read from
The feeding ratio Dk / D1 in the state is determined. And
Proceed to step S38. In step S38, the values obtained by the above processing
The feeding ratio Dk / D1 and the feeding amount D1
Then, the reference feed amount Dk in the initial state is obtained. continue,
The process proceeds to step S39 shown in FIG.
Similarly, the moving zoom lens position ZO2 is input. Step
In step S40, the moving amount of the zoom lens 2 is 15 mm or less.
Check if it is above. When the travel is less than 15mm
Jumps to step S43 and sets the correction coefficient hn to the value 1
Is a value corresponding to the moving zoom lens position ZO2.
And the value KH read from the memory 15A
DATA (ZO2) is fed out as it is and the ratio Dk / D2
And the process proceeds to step S44. In addition, the moving amount is
If it is 15 mm or more, the process proceeds to step S41,
An operation based on equation (13) is performed to determine a correction coefficient h2.
I will. In this case, the feed amount Dn in the equation (13) is used.
Should be applied to the feed amount D2.
The zoom lens position just before
In this case, the correction coefficient is calculated using the value D1 in this case.
Calculate h2. The accuracy problem in this regard is discussed above.
This is the same as in the first embodiment. Further, in step S42, the correction coefficient h2
And the value KHDATA (ZO) read from the memory 15A.
2), the feed-out ratio Dk / D2 is determined. And
The process proceeds to step S44 and subsequent steps.
This is the same processing as that of the embodiment, and
The lens position FO2 and the zoom position are not updated.
When the focus lens is driven, data such as FOn
Output to the unit 11 so that the focus lens 2
Is driven to the position. As described above, the video camera of this embodiment is
As with the camera of the first embodiment, the camera
A more accurate zoom track with less memory capacity
The locking operation is enabled. That is, the reference subject distance
∞DAT which is focus lens position data in (∞)
A (ZOn) and each zoom lens at a subject distance of 1 m
Showing the feeding ratio Dk / Dn corresponding to the closing position ZOn.
KHDATA (ZOn), which is the numerical value of the group, and correction
Only the equation (13) for calculating the coefficient hn is stored in the memory 15A.
Only enables high-precision tracking control.
is there. Note that the camera of this embodiment also
The zoom distance corresponding to the reference feed amount Dk for calculating the feed ratio
The zoom position is wide end W, but another zoom position is specified
You may. The subject distance is used as a reference for the extension position.
Uses data of separation, but is not limited to this.
Before applying the reference data on body distance,
This is the same as in the first embodiment. In addition, the above
A group of numerical values KHDATA (ZOn) indicating the ratio Dk / Dn
Subject distance is not limited to 1m, but data at other positions
It may be. In this embodiment and the first embodiment.
Was applied to a video camera, but of course
The gist of the invention is that other still video cameras and silver halide film
Also apply to zoom tracking control of camera
Can be. [0051] As described above, the camera of the present invention has a zoom
Of the focus lens in
The feeding amount is calculated using a single reference tracking curve data.
And a format corresponding to the reference focal length at a predetermined subject distance.
The feed amount of the lens and the feed ratio at each focal length,
Alternatively, it is determined by applying the correction coefficient etc.
So that the conventional camera data interpolation formula
Such as memory tracking control.
High-speed calculation with no need for the curve data
And high-precision zoom tracking control
However, there are many remarkable effects, such as possible with inexpensive equipment.
Have.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a main block configuration diagram of a video camera according to a first embodiment of the present invention. FIG. 2 is a view showing an example of a zoom tracking curve applied to a zoom tracking process of the video camera of FIG. 1; FIG. 3 is a flowchart of a zoom process of the video camera of FIG. 1; FIG. 4 is a part of a flowchart of zoom processing of a video camera according to a second embodiment of the present invention. FIG. 5 is a part of the flowchart of the zoom processing of the video camera of FIG. 4; FIG. 6 is an example of a zoom tracking curve applied to zoom tracking control of a conventional video camera. FIG. 7 is a diagram showing an optical system of a conventional video camera. FIG. 8 is a diagram showing a method of calculating a focus lens extension amount in zoom tracking control of a conventional video camera. FIG. 9 is a diagram showing a method of obtaining a focus lens extension amount in zoom tracking control using a data interpolation method of a conventional video camera. [Explanation of Signs] 2... Zoom lens 4... Focus lens 7... Zoom tracking control circuit (payout ratio calculating means, payout amount calculating means) 15) Memory (first group of numerical data holding means, second group of numerical data holding means, reference zoom tracking curve data holding means) 7A zoom tracking control circuit (Delivery ratio calculation means, correction coefficient calculation means) 15A Memory (numeric data holding means, reference zoom tracking curve data holding means) W ... wide end Position (first position) ZO2 to ZOn...
FO2 to FOn (appropriate position of the focus lens) Dk …………………………………………………………………………………………………………………………………………………………………………………………………………. ………………………………………………………………………………………………………………………………………………………………………………. VAL2... (Numerical value of the second group) ∞DATA (ZOn)... (Reference zoom tracking curve data) h1, h2, hn (correction coefficient) KHDATA (ZOn) (a group of numerical data)

Continuation of the front page (56) References JP-A-4-19703 (JP, A) JP-A-62-276011 (JP, A) JP-A-4-190310 (JP, A) JP-A-4-53368 (JP , A) (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 5/232 G02B 7/08

Claims (1)

(57) [of Claims] [Claim 1] for carrying data representative of the zoom tracking curve is a locus of proper positions of the focus lens corresponding to the reference object distance when moving the predetermined range's Murenzu a reference zoom tracking curve data retention unit, a first group numerical data retention means for carrying data number in the first group, a second group numerical data retention means for carrying data numbers of the second group , when the zoom lens is in the first position corresponding to a predetermined reference zoom magnification, the proper position and the zoom tracking car of the follower <br/> Kasurenzu corresponding to the Utsushitai distance
Reference movement amount of the focus lens, expressed as the distance between both the position of the proper position of the focus lens corresponding to the reference object distance derived from data representing the blanking and the first feed amount, the zoom lens is the First
Position when in the different second position and the upper Symbol proper position and the zoom focus lens corresponding to the Utsushitai distance
When the extension amount of the focus lens expressed as the interval between the two positions and the appropriate position of the focus lens corresponding to the reference subject distance derived from the data representing the system tracking curve is the second extension amount, The value of the payout ratio, which is expressed as the ratio of the payout amount to the payout amount and the second payout amount, is added to this second payout amount.
Serial first group of numerical value is one given first predetermined second constant is added Eject and Repetitive you calculated ratio operation, which is one of the numerical values of the second group constant value obtained by multiplying the Means for calculating a required second extension amount of the focus lens
To order, dividing the first feed amount serving the feed amount, by feeding ratio calculated by the feed ratio calculation means
And a feeding amount calculating means for calculating.