JP2005250314A - Zoom lens with image blur correction means - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zoom lens with an image blur correction means, which allows panning or tilting operation to be performed in accordance with a photographic condition without spoiling an image blur correction function of correcting image blur caused by vibration applied to the zoom lens. <P>SOLUTION: The zoom lens with the image blur correction means (comprising a vibration sensor 1 and a vibration-proof lens group 9) for correcting image blur caused by vibration applied to the zoom lens is provided with a function range change means 16 of the image blur correction means, which is capable of changing a range of a focal length on which the image blur correction means, and the range of the focal length on which the image blur correction means functions is changed in accordance with a photographic condition by the function range change means of the image blur correction means. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a zoom lens having image blur correction means, and more particularly to a zoom lens that corrects image blur in a zoom lens for a television camera.

  In recent years, zoom lenses for television cameras have increased in magnification and focus, and movement of the subject image on the telephoto side due to vibration of the intre and vibration of the lens due to wind has become a problem. Therefore, a zoom lens for a television camera equipped with an image blur correction function for driving a part of a lens group constituting a zoom lens as disclosed in Patent Document 1 and correcting a motion of a subject image caused by vibration has been developed. It was done.

  However, in the case of TV camera zoom lenses, the main users of which are professional photographers with proficient shooting techniques, image blur due to camera shake hardly poses a problem, unlike general video zoom lenses. . Therefore, in such a zoom lens for a television camera, image blur correction on the wide-angle side, which is necessary for a general video zoom lens, is not necessarily required. For this reason, image blur correction in a TV camera zoom lens is set so as not to function by fixing the image stabilizing lens group at the center position of the optical axis at a wide angle side from a certain focal length.

Another reason why image blur correction does not function on the wide-angle side in a TV camera zoom lens is to prevent operability during panning and tilting operations from being impaired.
That is, when performing panning and tilting, the zoom is once set to the wide angle side, then panning and tilting operations are performed, and the zoom is set to the original position again. Therefore, if image blur correction is functioning on the wide-angle side, the movement of the subject image due to panning performed by the photographer is corrected, and as a result, the movement of the subject image becomes unintended by the photographer. You will feel uncomfortable.

For the reasons described above, in a zoom lens for a television camera, for example, as shown in FIG. 8, image blur correction is not allowed to function on the wide angle side.
That is, FIG. 8 shows the relationship between the focal length and the suppression rate in the conventional zoom lens for a TV camera, and the focal length f On the telephoto side from n2, it is set to achieve a suppression rate N% (N is an arbitrary value) at which a good suppression effect can be felt. In contrast, the focal length f On the wide-angle side from n2, the suppression rate gradually decreases, and the focal length f The suppression rate is set to 0% when the angle is wider than n1.
JP 2002-318402 A

  However, in the zoom lens for a television camera equipped with the image blur correction function in the above-described conventional example, the range of the focal length in which the image blur correction functions is uniquely determined. There was a problem that it was not possible to shoot as expected. That is, the operation method at the time of panning differs depending on the shooting situation and is not necessarily uniform. For example, even when the zoom is operated to the wide angle side during panning, the extent to which the zoom is operated to the wide angle side depends on the shooting situation at that time.

  In some situations, the panning operation may be performed without zooming to the wide-angle side. For this reason, with conventional zoom lenses for TV cameras where the range of focal length for which image blur correction functions is uniquely determined, panning is performed in an area where image blur correction functions, and intentional movement of the subject image is performed. Is corrected by the image blur correction function, and as a result, the movement of the subject image becomes unintended by the photographer.

  Therefore, in view of the above problems, the present invention provides a zoom lens having an image blur correction unit that can perform a panning or tilting operation according to a shooting situation without impairing an image blur correction function with respect to vibration applied to the zoom lens. The object is to provide a lens.

The present invention provides a zoom lens having image blur correction means configured as follows.
That is, the zoom lens having the image blur correcting unit of the present invention includes a function range changing unit of the image blur correcting unit that can change a focal length range in which the image blur correcting unit functions, and the image blur correcting unit. The function range changing means can change the focal length range in which the image blur correcting means functions in accordance with the photographing situation.

  According to the present invention, a zoom lens having an image blur correction unit that can perform a panning or tilting operation according to a shooting situation without impairing an image blur correction function with respect to vibration applied to the zoom lens is realized. be able to.

  The best mode for carrying out the present invention will be described by the following examples.

[Example 1]
In the first embodiment of the present invention, an image blur correction apparatus in a zoom lens is configured by applying the above-described configuration of the present invention. In this embodiment, when applying the configuration of the present invention described above, the image blur correcting means is used as a lens barrel that holds a lens group including an optical axis decentering means for decentering the optical axis of the imaging optical system. For the input vibration, the optical axis decentering means can be driven to perform image blur correction based on the detection signal detected by the vibration detecting means.
Further, the function range changing means of the correcting means is a selecting means for selecting a focal length range in which the image blur correcting means functions, and the focal length range in which the image blur correcting means functions can be switched by the selecting means. Can be configured.
The function range changing unit of the correcting unit is a setting unit that sets a focal length range in which the image blur correcting unit functions. The setting unit arbitrarily sets a focal length range in which the image blur correcting unit functions. Can be configured to do.

Next, the present embodiment will be described more specifically with reference to FIGS.
Here, FIG. 1 is a diagram illustrating a configuration of an image blur correction apparatus in the zoom lens according to the first embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the image blur correction apparatus in the zoom lens according to the first embodiment of the present invention.
FIG. 3 is a graph showing the relationship between the focal length and the image blur correction control signal calculation coefficient in the apparatus according to the first embodiment of the present invention.
FIG. 4 is a diagram showing the relationship between the focal length and the suppression rate in the apparatus according to the first embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes a vibration sensor that detects vibration of a zoom lens (not shown), and 2 denotes a high-pass filter for removing a DC component contained in the output signal of the vibration sensor 1. 3 is an amplifier that amplifies the output of the high-pass filter 2, 4 is a high-pass filter that determines the signal band to be input to the CPU, 5 is an integration circuit that converts the signal of the vibration sensor 1 corresponding to the angular velocity into a signal corresponding to the angle, and 6 It is an AD converter for taking the output signal of the integration circuit 5 into the CPU.

Reference numeral 7 denotes an AD converter for fetching a zoom part position signal indicating the position of a zoom part (not shown) into the CPU, and reference numeral 8 denotes an AD converter for fetching a focus part position signal indicating the position of the focus part (not shown) to the CPU. is there.
9 is an anti-vibration lens group for decentering the optical axis of the zoom lens (not shown), 10 is an actuator for driving the anti-vibration lens group 9, and 11 is a position detection for detecting the position of the anti-vibration lens group 9. Means.

A CPU 12 calculates a control signal for the image stabilizing lens group 9 based on the outputs of the AD converter 6, AD converter 7 and AD converter 8. 13 is a DA converter for converting the calculation result of the CPU 12 into an analog signal, 14 is a drive circuit for driving the actuator 10, and 15 is for storing zoom portion position data, focus portion position data, and focal length data. 16 is a mode selection means for selecting a vibration isolation characteristic.
The nonvolatile memory 15 also stores a focal length-to-coefficient conversion data table that represents the relationship between the calculation coefficient for calculating the drive amount of the image stabilizing lens group 9 and the focal distance.

Next, the operation of the image blur correction apparatus in the zoom lens of the present embodiment will be described using the flowchart of FIG. This flowchart shows a series of operations of the CPU 12 in the zoom lens.
The CPU 12 proceeds to step 1 immediately after the power is turned on, and initializes the inside of the CPU 12. In step 2, the CPU 12 sets the cutoff frequency of the high / high pass filter 4. In step 3, the state of the mode selection means is read, and in step 4, the state is determined.
In step 4, when the mode selection means is set to the normal mode, a calculation coefficient data table for calculating the driving amount of the image stabilizing lens group at each focal length is read from the nonvolatile memory 15, Proceed. The relationship between the focal length and the calculation coefficient in the normal mode is indicated by a solid line in FIG.

Here, FIG. 3 will be briefly described. The horizontal axis in FIG. 3 is a focal length, and the vertical axis is a calculation coefficient (indicated as a coefficient in FIG. 3) for calculating the drive amount of the image stabilizing lens group.
As shown in FIG. 3, the calculation coefficient for calculating the drive amount of the image stabilizing lens group is set to increase as the focal length increases. This is because in a zoom lens in which the anti-vibration lens group is disposed closer to the image plane than the focus unit and the zoom unit, it is necessary to change the drive amount of the anti-vibration lens group according to the state of the zoom unit and the focus unit. Because. When the zoom unit is on the telephoto side, the driving amount of the image stabilizing lens group must be increased, and on the wide angle side, the driving amount of the image stabilizing lens group must be decreased. Further, in the zoom lens for a television camera, the image blur correction function is turned off on the wide angle side. On the wide-angle side from n1, the calculation coefficient for calculating the driving amount of the image stabilizing lens group is set to zero.

Subsequently, the operation of the CPU 12 will be described using the flowchart of FIG. In step 4, even when the mode setting means is set to the telephoto mode, a calculation coefficient data table for calculating the driving amount of the image stabilizing lens group at each focal length is read from the nonvolatile memory 15, and step 7 is executed. Proceed. The calculation coefficient for calculating the focal length in the telephoto mode and the driving amount of the anti-vibration lens group has a relationship shown by a broken line in FIG.
In step 7, the output signal of the integration circuit 5 that converts the output of the vibration sensor 1 into a voltage corresponding to the angle is AD-converted, and the conversion result is set to data.

Next, in step 8, the position signal of the zoom unit is AD converted and the buffer zoom position is set, and the position signal of the focus portion is AD-converted in step 9, and the buffer focus is set. Set to position.
In step 10, zoom position and focus The focal length data f corresponding to the position is read from the memory 15.
In step 11, the calculation coefficient k for calculating the driving amount of the image stabilizing lens group corresponding to the focal length data f is obtained using the data table read in step 5 or step 6.

Subsequently, in step 12, the control signal for the vibration-proof lens group 9 is calculated using the output data data of the vibration sensor and the calculation coefficient k for calculating the driving amount of the vibration-proof lens group. In step 13, the calculation signal is calculated. The result is output to the DA converter.
Thereafter, steps 3 to 13 are repeatedly executed until the lens is turned off.

FIG. 4 shows the relationship between the focal length and the suppression rate in the normal mode and the telephoto mode.
If priority is given to the operability during panning according to the shooting situation, the focal length f is set as shown in FIG. n1 to f The image blur correction function can be prevented from functioning within the range of t1, and the focal length f n1 to f Panning operability in the range of t1 can be improved.
[Example 2]
In the second embodiment of the present invention, the above-described configuration of the present invention is applied, and the image blur correction apparatus in the zoom lens is configured differently from the first embodiment.
Next, the present embodiment will be described more specifically with reference to FIGS.
Here, FIG. 5 is a diagram showing a configuration of an image blur correction apparatus in the zoom lens according to the second embodiment of the present invention.
FIG. 6 is a flowchart showing the operation of the image blur correction apparatus in the zoom lens according to the second embodiment of the present invention.
FIG. 7 is a diagram showing the relationship between the focal length and the image blur correction control signal calculation coefficient in the apparatus according to the second embodiment of the present invention.

  In FIG. 5, reference numeral 101 denotes a vibration sensor that detects vibration of a zoom lens (not shown), and reference numeral 102 denotes a high-pass filter for removing a DC component contained in the output signal of the vibration sensor 101. Reference numeral 103 denotes an amplifier that amplifies the output of the high-pass filter 102, reference numeral 104 denotes a high-pass filter that determines a signal band to be input to the CPU, reference numeral 105 denotes an integration circuit that converts a signal of the vibration detection unit 101 corresponding to angular velocity into a signal corresponding to an angle, and 106 Is an AD converter for taking the output signal of the integration circuit 105 into the CPU.

Reference numeral 107 denotes an AD converter for taking a zoom part position signal indicating the position of a zoom part (not shown) into the CPU, and reference numeral 108 denotes an AD converter for taking a focus part position signal indicating the position of the focus part (not shown) to the CPU. is there.
109 is an anti-vibration lens group for decentering the optical axis of the zoom lens (not shown), 110 is an actuator for driving the anti-vibration lens group 109, and 111 is a position detection for detecting the position of the anti-vibration lens group 109. Means.

A CPU 112 calculates a control signal for the image stabilizing lens group 109 based on the outputs of the AD converter 106, AD converter 107, and AD converter 108.
113 is a DA converter for converting the calculation result of the CPU 112 into an analog signal, 114 is a drive circuit for driving the actuator 110, and 115 is for storing zoom portion position data and focus portion position data / focal length data. The non-volatile memory 116 is an anti-vibration OFF-focal length setting means for setting a focal length for turning off the anti-vibration function. The non-volatile memory 115 also stores a focal length-to-coefficient conversion data table that represents the relationship between the calculation coefficient for calculating the driving amount of the image stabilizing lens group 109 and the focal distance.

Next, the operation of the image blur correction apparatus in the zoom lens of the present embodiment will be described using the flowchart of FIG. The flowchart in FIG. 6 shows a series of operations of the CPU 112 in the zoom lens.
The CPU 112 proceeds to step 101 immediately after the power is turned on, and initializes the inside of the CPU 112. In step 102, the CPU 112 sets the cutoff frequency of the high pass filter 104.
In step 103, the state of the image stabilization OFF-focal length setting means is read, and the image stabilization OFF-focal length data f is read. 1 is set.
In step 104, image stabilization OFF-focal length data f An arbitrary value a is added to 1, and the image stabilization ON-focal length data f 2 is calculated. f 1 and f The relationship between 2 and the relationship with the correction coefficient 1 described later is shown in FIG.
In step 105, the output signal of the integration circuit 105 that converts the output of the vibration sensor 101 into a voltage corresponding to the angle is AD-converted, and the conversion result is set to data.

Next, in step 106, the position signal of the zoom unit is A / D converted and the buffer zoom position is set, and the position signal of the focus portion is AD-converted in step 107, and the buffer focus is set. Set to position.
In step 108, zoom position and focus The focal length data f corresponding to the position is read from the memory 115. In step 109, a calculation coefficient k for calculating the drive amount of the image stabilizing lens group corresponding to the focal length data f is read from the memory 115.

  Subsequently, in step 110, a correction coefficient l for correcting the calculation coefficient k is calculated using equation (1).

l = 0: f ≦ f 1
l = (f−f 1) / (f 2-f 1): f 1 ≦ f ≦ f 2 (1)
l = 1: f 2 ≦ f

here,
f: focal length data obtained from the zoom position signal and the focus position signal f 1: Anti-vibration OFF-focal length data set by the focal length setting means f 2: Vibration isolation ON-focal length data.

In step 111, the control signal of the image stabilizing lens group 109 is calculated using the output data data of the vibration sensor, the calculation coefficient k, the correction coefficient l, and the like, and in step 112, the calculation result is output to the DA converter.
Thereafter, steps 103 to 112 are repeatedly executed until the lens is turned off.
Further, the above-described arbitrary value a may be set by the image stabilization OFF-focal length setting means.
By doing so, it is possible to arbitrarily switch the focal length range in which image blur correction functions.

  According to the configuration of each embodiment described above, panning and tilting operations are performed without impairing the suppression effect by switching the focal length range in which image blur correction functions to the telephoto side according to the shooting situation. It becomes possible to improve the sex.

It is a figure which shows the structure of the image blurring correction apparatus in the zoom lens of Example 1 of this invention. It is a flowchart figure which shows operation | movement of the image blurring correction apparatus in the zoom lens of Example 1 of this invention. It is the figure which showed the relationship between the focal distance in the apparatus of Example 1 of this invention, and the control signal calculation coefficient for image blur correction. It is the figure which showed the relationship between the focal distance and the suppression rate in the apparatus of Example 1 of this invention. It is a figure which shows the structure of the image blurring correction apparatus in the zoom lens of Example 2 of this invention. It is a flowchart figure which shows operation | movement of the image blurring correction apparatus in the zoom lens of Example 2 of this invention. It is the figure which showed the relationship between the focal distance in the apparatus of Example 2 of this invention, and the control signal calculation coefficient for image blur correction. It is the figure which showed the relationship between the focal distance and the vibration suppression rate in a prior art example

Explanation of symbols

1: Vibration sensor 2: High-pass filter 3: Amplifier 4: High-pass filter 5: Integration circuit 6: A / D converter 7: A / D converter 8: A / D converter 9: Anti-vibration lens group 10: Actuator 11 : Position detector 12: CPU
13: D / A converter 14: Drive circuit 15: Non-volatile memory 16: Mode selection means 101: Vibration sensor 102: High-pass filter 103: Amplifier 104: High-pass filter 105: Integration circuit 106: A / D converter 107: A / D converter 108: A / D converter 109. Anti-vibration lens group 110: Actuator 111: Position detector 112: CPU
113: D / A converter 114: Drive circuit 115: Non-volatile memory 116: Anti-vibration OFF-focal length setting means

Claims (4)

In a zoom lens having image blur correction means for correcting image blur due to vibration on the zoom lens,
A function range changing unit of an image blur correcting unit that enables a range of a focal length in which the image blur correcting unit functions to be changed, and the image blur correction is performed according to a shooting situation by the function range changing unit of the image blur correcting unit; A zoom lens having image blur correction means, wherein a range of a focal length at which the means functions can be changed.   The image blur correcting unit detects a detection signal detected by the vibration detecting unit with respect to vibration input to a lens barrel holding a lens group including an optical axis decentering unit that decenters the optical axis of the imaging optical system. 2. The zoom lens having an image blur correction unit according to claim 1, wherein the image blur correction unit is driven to perform image blur correction.   The function range changing unit of the correcting unit is a selecting unit that selects a focal length range in which the image blur correcting unit functions, and the selection unit can switch the focal length range in which the image blur correcting unit functions. A zoom lens having image blur correction means according to claim 1 or 2.   The function range changing unit of the correcting unit is a setting unit that sets a focal length range in which the image blur correcting unit functions, and the setting unit arbitrarily sets a focal length range in which the image blur correcting unit functions. A zoom lens having image blur correction means according to claim 1 or 2, wherein the zoom lens has image blur correction means.

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