JP7191661B2 - Zoom lens device and imaging device - Google Patents

Description

The present invention relates to a zoom lens device and an imaging device.

A zoom lens device for a television camera generally includes, in order from the object side to the image side, a focus lens group, a variable power lens group including a variator for variable power and a compensator for correcting fluctuations in the image plane due to variable power. and an imaging lens group. In such a zoom lens device, there is a problem that the focal point position fluctuates (out of focus occurs) depending on the angle (orientation) (of the optical axis) with respect to the horizontal (plane). The zoom lens device may be used tilted, for example, from a high place such as the top of a tower or a stadium in sports broadcasts, or from a helicopter in news reports. be. Therefore, the defocus caused by the attitude (difference) in such a case can be a problem.

Japanese Patent Application Laid-Open No. 2002-200000 discloses that as a countermeasure against focus deviation, the amount of focus deviation for each posture (angle) of a zoom lens device is measured in advance and stored as a correction amount, and based on the correction amount that matches the posture, a correction lens group is moved in the optical axis direction. It discloses a method of correcting (compensating for) defocusing due to posture by moving.

JP 2016-170292 A

Defocus due to posture is caused by changes in the deflection of the lens barrel, and tilting of the focus lens group and variable power lens group due to play in the mechanism. In particular, the defocus due to tilting of the lens group can appear steeply when the change in attitude (angle) from the horizontal becomes large to some extent. In addition, the attitude (angle) at which sharp defocusing occurs can also change due to changes in parts of the zoom lens device (e.g. expansion and contraction) due to usage environments such as temperature. Therefore, as shown in FIG. 9, the angle at which sharp defocus occurs may differ between when the correction amount is stored and when the zoom lens device is used. An excessive divergence from the out-of-focus amount may occur, giving the user a sense of discomfort.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lens device that is advantageous in reducing defocus due to, for example, posture.

A zoom lens device according to the present invention is a zoom lens device having a zoom lens group that moves in an optical axis direction, and includes an angle detection unit for detecting an angle of the zoom lens device with respect to the horizontal, and a focus position of the zoom lens device. a correction lens group that moves in the direction of the optical axis to correct variations; a storage unit that stores information about a correction amount of the focal position with respect to the angle; and based on the angle and the information, the correction lens group in the direction of the optical axis, wherein Δmb is the change in the correction amount per 1° of the change in the angle, and MAX Δmb is the Δmb at the angle θb at which Δmb is maximum. , where IC is the diameter of the image circle, the conditional expression 0<|MAXΔmb|/IC<4.50×10 ⁻³
is satisfied, let Δma be the change in the focal position per 1° of the change in the angle, let MAX Δma be the Δma at the angle θa at which Δma is maximum, and change the correction amount per 1° of the change in the angle θa as mb,
When |MAXΔma|≧3.0×10 ⁻³ (mm),
0.01<|mb/MAXΔma|<1.0
satisfies the following conditional expression,
When |MAXΔma|<3.0×10 ⁻³ (mm),
0.01<|mb/MAXΔma|<10.0
It is characterized by satisfying the following conditional expression.

According to the present invention, for example, it is possible to provide a lens device that is advantageous in reducing defocus due to posture.

1 is a schematic diagram showing the configuration of an imaging system that is Embodiment 1 of the present invention; FIG. 5 is a flow chart showing an example of processing in the first embodiment; 4 is a schematic diagram of the structure of the variable magnification lens group in Example 1. FIG. FIG. 10 is a schematic diagram showing how a part of the zoom lens group is tilted when there is a difference in posture in Example 1; FIG. 4 is a diagram showing the relationship between the amount of focus deviation and the amount of correction due to the difference in posture at the wide-angle end in Example 1, where (A) is a diagram when sharp focus deviation occurs, and (B) is a diagram when sharp focus deviation does not occur; is a diagram. 2 is a schematic diagram showing the configuration of an imaging system that is Embodiment 2 of the present invention; FIG. 10 is a flowchart illustrating an example of processing in Example 2; 7A and 7B are examples showing the relationship between the amount of focus deviation and the amount of correction due to the difference in posture at the wide-angle end in Example 2, where (A) is a diagram when a sharp focus deviation occurs, and (B) is a diagram in which the focal length is doubled by the extender. (C) is a diagram at the telephoto end, and (D) is a diagram when the temperature changes. FIG. 10 is a diagram showing the influence of a sharp change in defocusing angle due to a posture difference;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
The zoom lens apparatus of the present invention has a focus lens group that moves for focusing, a zoom lens group that moves for zooming, an aperture stop, and a relay lens group that does not move for zooming. A zoom lens device has an attitude difference detection section (angle detection section) that detects an angle with respect to a horizontal state when the optical axis direction is at an angle from the horizontal direction. In this specification, the angle (elevation/depression angle) of the optical axis direction of the zoom lens device with respect to the horizontal direction is also referred to as "posture difference". The zoom lens device of the present invention has a correction lens group that moves in the optical axis direction in order to correct defocus caused by a difference in posture. The correction lens group is arranged within the relay lens group. In the present invention, the correction amount of the image plane position in the optical axis direction by moving the correction lens group in the optical axis direction in order to correct the defocus due to the attitude difference satisfies the following conditional expression (1).
0<|MAXΔmb|/IC<4.50×10 ⁻³ (1)
Here, MAXΔmb is the maximum absolute value of the change Δmb in the amount of correction per 1° change in the attitude (elevation/depression angle) of the zoom lens device for correcting the focus shift due to the difference in attitude, and IC is the image circle. Size. The sign of the amount of correction of the position of the correction lens group is negative when moved toward the object side, and positive when moved toward the image side.

The sharp defocus at a certain elevation/depression angle is caused by tilting of the lens due to backlash that exists in the mechanism of the movable lens group. Therefore, the angle at which sharp defocusing occurs changes due to expansion and contraction of the constituent parts of the zoom lens device and changes in the physical properties of lubricants and anti-wear agents depending on operating environment conditions such as temperature.

Therefore, for example, when the focus deviation amount for each posture measured at the time of assembly adjustment is stored as a correction amount and the focus deviation due to the posture difference during use is corrected, as shown in FIG. Defocus may occur due to deviation from the out-of-focus amount.

In the present invention, in order to perform correction so as to prevent a sharp focus shift due to a posture difference, the correction amount is appropriately set so that the correction is gradually performed before and after the elevation/depression angle at which the sharp focus shift occurs, which is measured in advance. .

By setting the lower limit of conditional expression (1) to 0, it is a condition that the defocus caused by the difference in attitude is corrected. If the upper limit of conditional expression (1) is exceeded, the amount of correction will change too much, and if the angle at which sharp defocusing occurs changes depending on various conditions, the image will appear unnatural.

More preferably, conditional expression (1) is set as follows.
1.00×10 ⁻⁵ <|MAXΔmb|/IC<3.60×10 ⁻³ (1a)

Further, in the present invention, the change in the focal position per 1° change in the posture of the zoom lens device is defined as Δma, and the change in the focal position per 1° change in the posture of the zoom lens device at the angle θa at which the absolute value of Δma is maximized. is MAXΔma, and mb is the change in the correction amount per 1° change in posture of the zoom lens device at the angle θa detected when the zoom lens device is in use,
|MAXΔma|≧3.0×10 ⁻³ (mm) 0.01<|mb/MAXΔma|<1.0 (2)
When |MAXΔma|<3.0×10 ⁻³ (mm) 0.01<|mb/MAXΔma|<10.0 (3)
satisfy.

Conditional expressions (2) and (3) are defined as follows: where Δma is the change in focus position when the posture of the zoom lens device changes by 1°, the change in focus position at the angle θa at which Δma is maximum is expressed at the angle θa It defines the range of ratios of changes in correction amounts. More specifically, when the out-of-focus caused by the posture difference includes a sharp occurrence with respect to the posture difference, conditional expression (2) defines the occurrence of a steep out-of-focus with respect to the posture difference. is not included, it is defined by conditional expression (3).

When the focus shift due to the posture difference includes abrupt occurrence with respect to the posture difference, if the lower limit of conditional expression (2) is exceeded, the amount of correction for the amount of focus shift (fluctuation amount of the focal position) caused by the posture difference will be insufficient. , an image that gives a sense of discomfort is formed due to a sharp change in the defocusing angle. On the other hand, if the upper limit of conditional expression (2) is exceeded, it means that the amount of correction becomes excessively large with respect to the amount of defocus caused by the difference in posture. An image that gives a sense of discomfort is formed due to the change. In a predetermined region including the pre-obtained elevation/depression angle at which the sharp defocus occurs, the correction amount is changed smaller than the change in the correction amount with respect to the change in the elevation/depression angle at the pre-acquired elevation/depression angle at which the steep defocus occurs.

If the defocus caused by the posture difference does not include abrupt occurrence with respect to the posture difference, and the lower limit of conditional expression (3) is exceeded, the amount of correction becomes insufficient and the amount of defocus caused by the posture difference cannot be sufficiently corrected. On the other hand, when the upper limit of conditional expression (3) is exceeded, the amount of correction becomes excessively large with respect to the amount of defocus caused by the difference in posture, and an image that gives a sense of discomfort is formed.

More preferably, conditional expression (2) is set as follows.
0.1<|mb/MAXΔma|<1.0 (2a)
More preferably, conditional expression (3) is set as follows.
0.1<|mb/MAXΔma|<5.0 (3a)

The zoom lens device shown in Example 1 will be specifically described with reference to FIG.
Embodiment 1 FIG. 1 shows the configuration of an imaging apparatus that is Embodiment 1 of the present invention.

The imaging apparatus according to the first embodiment includes a zoom lens device 0, an imaging device 7 arranged on the image plane of the zoom lens device 0, and a video signal processing circuit 8 for obtaining a video signal based on a signal from the imaging device 7. have A zoom lens device 0 has a focus lens group 1 , a variable magnification lens group 2 , an aperture stop 3 , a front relay lens group 4 , an extender section 5 and a rear relay lens group 6 .

The variable magnification lens group 2 is composed of a lens group (variator 2a) that moves along the optical axis to vary the magnification, and a lens group (compensator 2b) that corrects the image plane that fluctuates along with the magnification variation. An extender unit 5 is composed of a unity magnification lens group 5a and an extender lens group 5b that shifts the focal length range to the telephoto side, and either one of the lens groups is selectively inserted and removed on the optical axis. . In Example 1, the rear relay lens group 6 functions as a correction lens group and moves in the optical axis direction to correct defocus.

A focus driving unit 9 drives the focus lens group 1, and drives the focus lens group 1 in the optical axis direction by a mechanism such as a helicoid or a cam. A zoom drive unit 10 drives the variable power lens group 2, and drives the variable power lens group 2 in the optical axis direction by means of a cam mechanism. A diaphragm driver 11 adjusts the aperture diameter of the aperture diaphragm 3 . Reference numeral 12 denotes a correction lens group driving section (control section) for driving the correction lens group. 13 is a switching portion of the extender portion 5 . A posture detection unit 14 detects the angle (depression angle) of the optical axis direction of the lens with respect to the horizontal direction. 15 is a correction lens group detection unit. A calculation unit (control unit) 16 performs calculations for controlling various driving operations of the entire zoom lens apparatus. A storage unit 17 stores a focal position correction amount based on the amount of defocus caused by a change in posture.

In the first embodiment, the amount of defocus caused by the change in posture is measured during product assembly adjustment, and the correction amount according to the measurement result is stored in the storage unit 17 . Then, the calculation unit 16 selects the focal position correction amount stored in the storage unit 17 based on the signal from the attitude detection unit 14 and inputs it to the driving unit 12 of the correction lens group. Based on the signal from the calculation unit 16, the correction lens group driving unit 12 moves the correction lens group 6 in the optical axis direction to correct the defocus due to the difference in posture.

FIG. 2 is a flow chart showing an example of processing according to the first embodiment. The following processes indicated by adding S to the reference numerals of the processing steps are realized by the CPU of the calculation unit 16 executing the control program.

In S1, the power of the zoom lens device shown in FIG. 1 is turned on. In S2, the angle sensor, which is the attitude detection unit 14, detects the angle (elevation/depression angle) of the optical axis direction of the zoom lens device with respect to the horizontal direction. In S3, processing is performed to determine whether the angle detected in S2 is in a horizontal state. If the detected angle is not horizontal, a process S4 of reading out correction data corresponding to the angle from the storage unit 17 is performed. If the detected angle is horizontal, the process proceeds to S6. In S5, the correction lens group is moved based on the read correction data, and the process of correcting the defocus due to the difference in posture is performed. In S6, the correction lens position detection unit 15 performs processing for confirming the position of the correction lens group after movement.

FIG. 3 is a diagram showing the zoom cam structure in the horizontal state in the embodiment 1. FIG. 2a is a variator for moving along the optical axis to perform zooming, and 2b is a compensator for correcting the positional variation of the image plane accompanying zooming. 101 is a lens barrel. 102 is a straight groove. 103 is a cam cylinder and 104 is a cam groove. Reference numeral 105 denotes positioning rollers for moving the variator 2a and the compensator 2b in alignment with the cam grooves. 106 is a roller for moving the variator 2a and the compensator 2b along the linear groove 102;

In the zoom lens apparatus of Example 1, by rotating the cam cylinder 103, the variator 2a and the compensator 2b are moved in the optical axis direction along the trajectory of the cam groove 104, thereby realizing zooming.

Three linear grooves 102 are machined in the lens barrel 101 at equal intervals in the circumferential direction around the optical axis of the lens barrel 101. There are three evenly spaced, each positioned to slidably engage a corresponding linear groove.

FIG. 4 shows an example of the zoom cam structure shown in FIG. 3 when the compensator 2b portion is inclined by a certain angle θ from the horizontal state. The cam groove 104 is connected to the cam groove 104 only at one point of the positioning roller 105, and since there is no restraining force in the optical axis direction at the three engaging portions of the straight groove 102 and the roller 106, the angle θ is given as the attitude difference. In some cases, the compensator 2b may suddenly fall at a certain angle θ'. Due to the tilt θ' of the compensator 2b, the focal position changes abruptly, resulting in out-of-focus. In addition, as described above, the inclination angle θ' of the compensator 2b and the angle θ at which the inclination occurs are due to the characteristics of the components, such as expansion and contraction of the components due to changes in the usage environment such as temperature, and changes in the physical properties of the lubricant and anti-wear agent. change for other reasons. The same applies to the variator 2a.

Therefore, even if there is a change in the operating environment such as the temperature, the image after correction does not give a great sense of incongruity. In order to correct the sharp defocus caused by tilting the lens group due to the difference in posture, the amount of correction is appropriately set so that the correction is performed gradually within a predetermined range that includes the pre-measured angle at which the sharp defocus occurs. There is a need.

5A and 5B show the relationship between the defocus amount (solid line) due to the attitude difference of the zoom lens device and the correction amount (broken line) by the correction lens group in the first embodiment. FIG. 5(A) shows a case where the play due to manufacturing error etc. is large (|MAXΔma|≧3.0×10 ⁻³ (mm)), and FIG. 5(b) shows a case where the play due to manufacturing error etc. is small (| MAXΔma|<3.0×10 ⁻³ (mm)). The amount of defocus is a value measured at 25° C. under the conditions of open aperture, infinite object distance, wide-angle end, and the same magnification. Also, the size (diameter) of the image circle of the zoom lens device in Example 1 is 1.12×10 ¹ mm.

Under the conditions of FIG. 5(A), the angle (elevation/depression angle) θa at which Δma is the maximum, where Δma is the change in focal position per 1° of change in the posture of the zoom lens device obtained based on prior measurements. is 22°. Also, the focal position change MAXΔma at the angle θa is 4.40×10 ⁻³ mm. In this case, the amount of change in the focal position per unit elevation/depression angle measured in advance in a predetermined angle range including 22°, the angle at which a sharp focus shift occurs due to the attitude difference (an angle that has been measured and confirmed in advance). Set a correction amount that will result in a smaller amount of change. As a result, even when the angle at which sharp defocusing occurs changes, it is possible to perform correction with little sense of incongruity. In FIG. 5A, when the change in the amount of correction when the posture of the zoom lens device changes by 1° is Δmb, the angle θb at which Δmb becomes maximum is 22°. is set to 2.40×10 ⁻³ mm.

Table 1 shows values corresponding to each conditional expression in FIG. The conditions in FIG. 5A satisfy all conditional expressions. With this configuration, even if the angle at which a sharp focus shift occurs changes due to expansion and contraction of the constituent parts of the zoom lens device due to changes in the physical properties of lubricants and anti-wear agents, and changes in the physical properties of lubricants and anti-wear agents, the focus shift due to differences in posture will not occur. It is possible to realize correction with little sense of discomfort caused by.

FIG. 5B shows the angle θa at which Δma is maximized, where Δma is the change in focal position per 1° of change in the posture of the zoom lens device obtained based on prior measurements, etc., under the conditions described above. 24°. The focal position change MAXΔma at the angle θa (=24°) is 8.00×10 ⁻⁴ mm. In such a case, since the maximum absolute value of Δma (|MAXΔma|) is not large (there is no sharp defocus), the amount of defocus previously measured and confirmed for each angle is used for correction used in actual photography. There is no problem even if it is set as a quantity. In FIG. 5B, the angle θb at which Δmb is maximized is 24°, where Δmb is the change in correction amount per 1° of change in posture of the zoom lens device detected during use of the zoom lens device. be. The maximum change in correction amount at the angle θb, Δmb, is 8.00×10 ⁻⁴ mm.

Table 1 shows the values corresponding to each conditional expression in FIG. All of the conditional expressions in FIG. 5B are satisfied, and the correction of the out-of-focus due to the difference in posture is less uncomfortable.

Note that the posture detection unit in the first embodiment can also detect angular velocity, and may perform defocus correction based on the velocity of tilting from the horizontal state (angular velocity in the elevation/depression angle direction) in addition to the above-described elevation/depression angle.

FIG. 6 shows the configuration of an imaging system that is Embodiment 2 of the present invention.
Compared to the first embodiment, the imaging system of the second embodiment includes a focus position detection unit 18 for detecting the position of the focus lens group 1, a zoom position detection unit 19, an aperture detection unit 20, an equal-magnification lens group 5a, and an extender lens. The difference is that an extender detection section 21 for detecting switching of the group 5b and a temperature detection section 22 are provided. Other configurations are the same.

In the zoom lens apparatus of Example 2, a correction value for correcting defocus caused by changes in posture, changes in the position of the focus lens group, changes in the zoom position, changes in the aperture, changes in temperature, and switching of the extender is set. , are stored in the storage unit 17 in advance. Therefore, the calculation unit 16 detects signals (posture, zoom position, aperture opening) detected by the posture detection unit 14, the focus position detection unit 18, the zoom position detection unit 19, the aperture detection unit 20, the extender detection unit 21, and the temperature detection unit 22. degree, state of the extender, temperature), the correction amount stored in the storage unit 17 is read out or calculated, and input to the driving unit 12 of the correction lens group. The correction lens group driving section 12 moves the correction lens group 6 in the optical axis direction based on the signal from the calculation section 16 to correct the defocus.

The defocus correction information stored in the storage unit 17 may be information in the form of a table, or may be information obtained by formulating the defocus amount with respect to various factors.

As a different form of this embodiment, in addition to the amount of correction due to changes in posture, the storage unit 17 stores the position of the focus lens group, the position of the zoom lens group, the state of the diaphragm, the temperature, and the state of the extender. Correction information relating to at least one correction amount of the correction value for correcting the correction may be stored. Moreover, in addition to the means for detecting the attitude, it is sufficient to have at least one detection unit for detecting the position of the focus lens, the position of the zoom lens group, the state of the diaphragm, the temperature, and the state of the extender.

FIG. 7 is a flow chart showing an example of processing according to the second embodiment. The following processes indicated by adding S to the reference numerals of the processing steps are realized by the CPU of the calculation unit 16 executing the control program.

In S1, the power of the zoom lens shown in FIG. 6 is turned on, and the process proceeds to S11.
In S11, the state of a switch (switching section) (not shown) for switching whether or not to perform focus shift correction due to a posture difference is determined. If the focus deviation correction function based on the attitude difference is ON, the process proceeds to S2, and if the focus deviation correction function based on the attitude difference is OFF, the process proceeds to S21.

In S2, the angle sensor, which is the orientation detection unit 14, performs processing for detecting the orientation of the zoom lens device, and proceeds to S21.

In S21, processing for detecting the position of the focus lens group by the focus position detection unit 18 is performed, and the process proceeds to S22.
In S22, the zoom position detector 19 detects the position of the zoom lens group, and the process proceeds to S23.
In S23, the diaphragm detection unit 20 detects the opening of the diaphragm, and the process proceeds to S24.
In S24, the temperature detection unit 22 detects the temperature, and the process proceeds to S25.
In S25, the extender detection unit 21 detects the optical system of the extender inserted in the optical path, and the process proceeds to S4.

In S4, based on the orientation of the zoom lens device, the position of the focus lens group, the position of the zoom lens group, the opening of the aperture, the temperature, and the state of the extender detected in S2 and S21 to S25, correction data is stored from the storage unit 17. Read processing is performed. In S5, the correction lens group is moved based on the read correction data, and the process of correcting the defocus due to the difference in posture is performed. In S6, the correction lens position detection unit 15 performs processing for confirming the position of the correction lens group after movement.

As a different form of this embodiment, the order of the processes from S2 and S21 to S25 may be changed. Moreover, it is also possible that any one of the processes from S2 and S21 to S25 is not executed.

8A to 8D show the amount of defocus (solid line) due to the difference in posture of the zoom lens device obtained based on preliminary measurements, etc., and the amount of correction lens group used in actual photography in Example 2. The relationship with the correction amount (broken line) is shown.

8A and 8B are values measured under the conditions of 25° C., open aperture, infinite object distance, and wide-angle end. Also, FIG. 8A shows the case of 1:1 magnification, and FIG. 8B shows the case of doubling by the extender lens group.

FIG. 8C shows correction for the telephoto end. FIG. 8(D) shows a case where the amount of out-of-focus is reduced with respect to the amount of correction because the amount of out-of-focus changes due to changes in temperature.

The size of the image circle of the zoom lens device in FIG. 8A is 1.12×10 ¹ mm. In such a case, by gradually correcting the angle before and after the angle at which the steep focus shift occurs due to the posture difference, it is possible to perform correction with little discomfort even when the occurrence angle changes.

In FIG. 8A, when the change in the correction amount per 1° change in the posture of the zoom lens device is Δmb, the angle θb at which Δmb becomes maximum is 22.5°. The maximum change in Δmb is 6.00×10 ⁻⁴ mm. The angle θa at which Δma is maximized is 22.5°, where Δma is the change in focal position per 1° change in posture of the zoom lens device. The change MAXΔma of the focus position at the angle θa is 1.60×10 ⁻³ mm, and the change mb of the correction amount at the angle θa is 6.00×10 ⁻⁴ mm.

Table 2 shows values corresponding to each conditional expression in FIG. The conditions in FIG. 8A satisfy all conditional expressions. With this configuration, even if the angle at which a sharp focus shift occurs changes due to expansion and contraction of the constituent parts of the zoom lens device due to changes in the physical properties of lubricants and anti-wear agents, and changes in the physical properties of lubricants and anti-wear agents, the focus shift due to differences in posture will not occur. It is possible to realize correction with little sense of discomfort caused by.

FIG. 8(B) doubles the focal length of FIG. 8(A) by the extender lens group. In the zoom lens apparatus according to the second embodiment, the movable lens group that causes sharp defocus due to the difference in posture is located closer to the object side than the extender unit, so the amount of defocus becomes larger than when the magnification is 1:1. Also, the size of the image circle in this example is 2.24×10 ¹ mm. Even in such a case, it is sufficient to gradually correct the angles before and after the angle at which the sharp defocusing occurs.

In FIG. 8B, when the change in the correction amount when the posture of the zoom lens device is changed by 1° is Δmb, the angle θb at which Δmb becomes maximum is 22.5°. The change in amount MAXΔmb is 3.00×10 ⁻³ mm. Assuming that the change in focal position when the posture of the zoom lens device is changed by 1° is Δma, the angle θa at which Δma is maximum is 22.5°, and the maximum focal position change Δma at that angle θa is 7.5°. 20×10 ⁻³ mm. The change mb of the correction amount at the angle θa is 3.00×10 ⁻³ mm.

Table 2 shows values corresponding to each conditional expression in FIG. All of the conditional expressions in FIG. 8B are satisfied, and correction of defocusing caused by a difference in posture is less uncomfortable.

FIG. 8C shows the case of the zoom lens apparatus of Example 2 at the telephoto end at 25° C., full aperture, infinite object distance, life size magnification. In a zoom lens device like that of the second embodiment, the fluctuation of the focal position due to the positional fluctuation of the movable lens group becomes very large with respect to the wide-angle end. The angle θb at which Δmb is maximized is 12°, and the angle θa at which Δma is maximized is 12°. In such a case, even if the correction amount is increased, it is not possible to cope with sharp changes in the defocus angle. Therefore, as shown in FIG. 8C, correction is performed so as to correct the focus shift at an angle close to the horizontal state in which sharp focus shift does not occur.

FIG. 8(D) differs from FIG. 8(A) in operating temperature. The angle θb at which Δmb is maximized is 26°, and the angle θa at which Δma is maximized is 22°. Even in such a case, by appropriately setting the correction amount within the range of conditional expression (2), it is possible to cope with the change in the amount of defocus due to the change in temperature.

Examples of the amount of focus deviation and the amount of correction thereof due to the difference in posture are shown in Embodiments 1 and 2, but the amount of focus deviation and the amount of correction are not limited as long as the conditional expressions are satisfied.

In the illustrated embodiment, the correction lens group is arranged within the relay lens group, but the invention is not so limited and may be arranged in other positions.

Moreover, although preferred embodiments of the present invention have been described in Examples 1 and 2, the present invention is not limited to these embodiments, and modifications and changes are possible within the scope of the gist thereof.

0 Zoom lens device 2 Magnifying lens group 10 Zoom driver 12 Compensation lens group driver 14 Attitude difference detector 16 Calculator 17 Correction data storage

Claims (10)

A zoom lens device having a zoom lens group that moves in an optical axis direction,
an angle detection unit that detects the angle of the zoom lens device with respect to the horizontal;
a correction lens group that moves in the direction of the optical axis in order to correct fluctuations in the focal position of the zoom lens device;
a storage unit that stores information about a correction amount of the focal position with respect to the angle;
a control unit that performs control for moving the correction lens group in the optical axis direction based on the angle and the information;
Let Δmb be the change in the correction amount per 1° change in the angle, MAXΔmb be the Δmb at the angle θb at which Δmb is maximum, and IC be the diameter of the image circle, then the conditional expression 0<|MAXΔmb|/IC<4. 50× ^10-3
satisfies the
Let Δma be the change in the focal position per 1° change in the angle, MAX Δma be the Δma at the angle θa at which Δma is maximum, and mb be the change in the correction amount per 1° change in the angle θa,
When |MAXΔma|≧3.0×10 ⁻³ (mm),
0.01<|mb/MAXΔma|<1.0
satisfies the following conditional expression,
When |MAXΔma|<3.0×10 ⁻³ (mm),
0.01<|mb/MAXΔma|<10.0
A zoom lens device characterized by satisfying the following conditional expression: 2. The zoom lens apparatus according to claim 1, wherein the control section includes a drive section that drives the correction lens group. 3. The zoom lens apparatus according to claim 1, wherein the control section performs the control based on at least one of the position and temperature of the zoom lens group. 4. Among claims 1 to 3, wherein the control unit obtains a correction amount for the focal position of the zoom lens device based on at least one of the position and temperature of the zoom lens group. A zoom lens device according to any one of the preceding items. a focus lens group that moves in the optical axis direction for focusing, an aperture diaphragm, and an extender lens group that changes the focal length range of the zoom lens device by being inserted into and removed from the optical path;
The information includes at least one of the position of the focus lens group, the position of the zoom lens group, the opening degree of the aperture stop, the insertion/extraction of the extender lens group, the temperature, and the focus with respect to the angle. 5. The zoom lens apparatus according to any one of claims 1 to 4, further comprising information on a position correction amount. A detection unit for detecting the position of the focus lens group, a detection unit for detecting the position of the zoom lens group, a detection unit for detecting the opening degree of the aperture stop, and a state related to insertion/removal of the extender lens group. 6. The zoom lens device according to claim 5, comprising at least one of a detection section and a detection section for detecting temperature. It has a relay lens group that is arranged closest to the image side and does not move for zooming,
7. The zoom lens apparatus according to claim 1, wherein the correcting lens group is included in the relay lens group. the angle detection unit includes a sensor that detects an angular velocity of the zoom lens device;
The storage unit stores, as the information, information about the correction amount for the angle and the angular velocity,
8. The zoom lens apparatus according to any one of claims 1 to 7 , wherein the control section performs the control based on the information, the angle, and the angular velocity. 9. The zoom lens apparatus according to any one of claims 1 to 8 , further comprising a switching section for switching whether or not to perform the control by the control section. a zoom lens device according to any one of claims 1 to 9 ;
and an imaging device arranged on the image plane of the zoom lens device.

Images