JP3360123B2 - Image stabilization photographing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an interchangeable lens type photographing apparatus such as a camera and, more particularly, to an image shake correcting photographing apparatus suitable for application to an interchangeable lens type photographing apparatus capable of correcting image shake during photographing.

[0002]

2. Description of the Related Art In a photographing apparatus represented by a camera,
Japanese Patent Application Laid-Open No. 2-66535 and Japanese Patent Application Laid-Open No. 183217/1990 disclose an image blur correction photographing apparatus that detects a change in the angle of the optical axis due to camera shake and the like and thereby corrects a photographed image.
The one shown in Japanese Patent Application Laid-Open Publication No. H10-26095 is conventionally known.

Here, the former camera capable of correcting image blur is an example in which the photographing optical system is a single lens optical system, and includes a shake detecting means for detecting image blur and this detecting means. And a driving unit for driving a single lens optical system serving as a shake correction optical system in accordance with the shake correction signal in order to perform shake correction, thereby preventing image shake due to camera shake or the like. Note that the former camera is provided with a restraining means such as an electromagnetic braking device so that the optical system for preventing shake is free during shooting, while the optical system is held in a restrained state when not shooting. Has been adopted.

Further, the latter lens barrel capable of correcting image shake is provided with an angular accelerometer as a shake detecting means at a desired position which becomes a center of gravity when coupled to a camera body in a photographing optical system using an in-focus telephoto lens. In this example, image blur prevention is performed by mounting a part of the photographing optical system by a shake correction driving unit in accordance with the mounted optical system.

[0005]

By the way, in the above-mentioned photographing apparatus, an inner focus type lens is mainly used as a telephoto lens of a camera which most requires an image blur correction technique.

However, the focal length (f) of such an in-focus lens gradually changes from infinity shooting to close-range shooting.

Therefore, in a telephoto lens using such an inner focus type lens, the correction amount can be obtained only by the image shake correction drive control by the simple image shake amount calculation method disclosed in the former conventional example described above. Causes an error.

Further, in such a telephoto lens, an optical lens thickness (a distance H between main planes) in a photographing optical system is required.
Since H ′) also changes, the distance “a” between the photographing lens and the subject and the distance “b” between the photographing lens and the film surface in the conventional example described above are simply obtained from the subject photographing distance alone. I can't.

The problems associated with the change in focal length and the change in lens thickness occur not only in telephoto lenses but also in zoom lenses.

Further, in these photographing apparatuses, the image blur due to the rotation in the photographing apparatus is removed by specifying the rotation center position on the apparatus optical axis. It is possible to remove the influence caused by the movement of the image and to calculate the image blur amount more accurately.

However, in a photographing apparatus such as an interchangeable lens camera, the position of the center of rotation of the photographing apparatus on the optical axis changes depending on the combination of the lens barrel and the camera body. Therefore, such a lens-interchangeable photographing apparatus cannot accurately calculate the amount of image blur, and it is necessary to take some measures that can solve such a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in a conventional image blur correcting photographing apparatus having a detecting means for detecting an angle variation, the camera body and the lens barrel need not be distinguished. An object of the present invention is to provide an image shake correction photographing apparatus that can perform more accurate image shake correction even when combined as described above.

[0013]

In order to respond to such a demand, an image blur correction photographing apparatus according to the present invention comprises: an image pickup means; a photographing optical system held by a lens barrel constituting the photographing apparatus; An image blur correction driving unit that relatively shifts a part of the imaging optical system and the screen for image blur correction, an angle change detection unit that detects an angle change of an optical axis of the imaging device, A first storage unit for storing information relating to the weight of a camera body constituting the photographing apparatus; a second storage unit for storing information relating to the weight of the lens barrel; a first storage unit and a second storage unit from the means
Based on the information, the rotation center of the image blur when the camera body and the lens barrel constituting the image capturing apparatus are combined
The rotation center determining means for determining the angle change detecting means
Based on these outputs and the output from the rotation center determining means.
An image blur correction drive control unit that drives and controls the image blur correction drive unit.

An image blur correcting photographing apparatus according to the present invention.
Is the weight of the camera body stored in the first storage means.
Information about the amount is the weight of the camera body and the position of the center of gravity.
And a lens mirror stored in the second storage means.
The information on the weight of the tube is the weight of the lens barrel and the center of gravity.
Location. Further, the image blur according to the present invention
The correction photographing device consists of a camera body and a lens that constitute the photographing device.
Calculation to calculate the total weight when combined with the lens barrel
Means for determining the center of rotation based on the calculating means
Things.

[0015]

According to the present invention, each characteristic value (focal length: f
(= F ′), the optical lens thickness: T, the distance between the principal plane H ′ on the rear side of the lens and the distance between the imaging planes: b, etc. Since the center of rotation is determined based on the position of the center of gravity and the weight of the lens barrel, the center of rotation can be calculated accurately every time the combined attitude of the lens barrel and camera body changes. , Calculate the exact amount of image blur,
The image blur correction optical system is driven and controlled in a required state by the control unit and the drive unit, so that image blur correction can be performed.

According to the present invention, the first storage means
The stored information on the weight of the camera body is
Second storage means including the weight of the body and the position of the center of gravity;
Information about the weight of the lens barrel stored in the
Including the weight of the lens barrel and the position of the center of gravity, no matter how the lens barrel and the camera body are combined, the exact center of rotation can be calculated and determined, and the exact amount of image shake can be calculated. The image blur correction can be performed by controlling the drive of the image blur correction optical system in a required state by the control unit and the drive unit.

[0017]

1 to 4 show an embodiment of an image blur correction photographing apparatus according to the present invention. In these figures, first, a lens suitable for applying the present invention using FIG. The schematic configuration of the entire interchangeable camera will be described below.

That is, in FIG. 1, reference numeral 1 denotes a camera body, in which a camera-side CPU 2 provided by a one-chip microcomputer (hereinafter, referred to as a first MCU) is provided for communication with a lens barrel 3. The camera is configured to perform various drive controls such as release, exposure, and film winding.

Reference numeral 4 denotes a lens barrel-side CPU provided by a one-chip microcomputer (hereinafter, referred to as a second MCU) provided in the lens barrel 3, which communicates with the camera body 1 and various types of lenses including image blur correction. It is configured to perform drive control.

Reference numeral 5 denotes an angular velocity detecting unit provided on the lens barrel 3 side, for detecting a rotational shake which causes image shake such as hand shake as an angular velocity. In addition,
As the angular velocity detector 5, a known vibration gyro angular velocity meter may be used.

Reference numeral 6 denotes an image blur correction drive unit for shifting and driving the image blur correction optical system constituting a part of the photographing optical system disposed in the lens barrel 3 in a required state. And a monitor unit for detecting the shift amount of the second and transmitting the same to the second MCU 4 as a monitor signal.

Reference numeral 7 denotes a focus position detection unit for detecting the position of the focus adjustment optical system in the photographing optical system, which is constituted by sensor means such as an encoder for reading the rotational position of the focus cam ring. Detect state.

In the figure, reference numeral 8 denotes an electrical contact, which makes electrical connection when the camera body 1 and the lens barrel 3 are combined, and enables communication between the camera body 1 and the lens barrel 3.

Here, the configuration and the like of each part of the camera body 1 and the lens barrel 3 other than those described above are conventionally known, and a detailed description thereof will be omitted.

FIG. 2 is a block diagram of a control circuit in the camera body 1 and the lens barrel 3 shown in FIG. Here, the electrical contact 8 is configured as follows in order to perform clock synchronous communication.

That is, reference numerals 8a and 8A in the figure denote clock terminals (SCLK, SCLK) for outputting a clock from the body 1 side. 8b is a lens barrel 3
8B is a data input terminal (SIN) on the body 1 side, and 8c is a lens barrel 3
A data input terminal (SIN) on the side and a data output terminal (SOUT) on the body 1 side. Note that 8d, 8
D is a ground terminal (GND, GND).

FIG. 3 is an explanatory diagram for explaining the relationship between shake (change in the angle of the optical axis) and image shake of a subject image in an interchangeable lens camera as an image shake correcting photographing apparatus according to the present invention.

Here, a in the figure is a photographing object to a photographing optical system.
The distance between the principal planes (H) on the front side of the lens, b is a photographing optical system
The distance between the principal plane (H ') on the rear side of the lens and the image plane is defined as the distance.
The “imaging plane” is specifically on the photographic film plane, and is always at a fixed position with respect to the camera body 1.

Further, in the figure, T is the distance between the principal plane (H) on the front side of the photographing optical system and the lens and the principal plane (H ') on the rear side of the lens, and is the above-mentioned optical lens thickness.

In the figure, R is the distance between the object to be imaged and the image plane, and R is expressed as follows: R = a + T + b (1)

Further, the "change in the angle of the optical axis" means that the entire camera (photographing apparatus) has swung so as to rotate the optical axis around a certain point on the optical axis of the photographing optical system. The rotation center is a point N, and the distance between the point N and the image plane is
In the figure, n is set.

Further, as shown in FIG. 3, it is assumed that the optical axis of the entire camera around the point N has changed by dθ within a certain short time (= dt) with respect to the stationary subject.

In other words, with the optical axis of the apparatus of the present invention as a reference, it can be considered that the direction of the subject has changed (−dθ) with respect to the apparatus of the present invention around the point N. In FIG. 3, the amount of movement of the subject accompanying this change is indicated by Do.

If the amount of change in the incident angle of the subject light to the photographing optical system is (-dφ), the following value is obtained. −dφ = (a + T + b−n) × (−dθ) / a = −dθ × (R−n) / a (Formula 2)

Accordingly, the image shake amount (indicated by Dim in FIG. 3) has the following value from the relation of image formation. Dim = b × (−dφ) = − b × dθ × (R−n) / a (Equation 3)

In the apparatus of this embodiment, if the relationship between the shift amount of the correction optical system and the image movement is ds = di, the correction optical system must be moved in the reverse direction in order to correct the above-mentioned image shake amount Dim. Is shifted by the same amount.

That is, if the shift drive amount of the correction optical system at the optical axis change amount dθ is ds (dθ), the following value is obtained. ds (dθ) = − Dim = b × dθ × (R−n) / a (Equation 4)

Generally, since ds = di × C, the following is obtained. ds (dθ) = C × b × dθ × (R−n) / a (C: constant) (Equation 5)

When the position of the shake correcting optical system is not already at the center position (for example, when the image shake correcting drive is being continued).
3 and FIG. 3 and (Equation 1) to (Equation 5) described above.
It is sufficient to perform the same image blur correction drive as described in the above.

Further, the shift position of the correction optical system at the start of the image blur correction drive (t1) is set to S
If (t1) is set, the shift position S (t1 + dt) of the correction optical system after dt time has the following relationship.

S (t1 + dt) = S (t1) + ds (dθ) = S (t1) + {C × b × dθ × (R−n) / a} (Equation 6)

Then, the above-mentioned (Equation 4) and (Equation 5)
In the inner focus type lens as in this embodiment, the focal length f (= f ′) and the lens thickness “T” change depending on the shooting distance “R”.

Here, in the lens of the general all-group extension type, the values of the focal length "f (= f ')" and the lens thickness "T" do not change, so only this numerical information is previously stored in the second MCU.
If the photographing distance “R” can be detected (for example, the rotational position of the lens distance ring is detected), “a” and “b” can be calculated by a simple calculation (Newton's imaging formula). Desired.

However, in the above-described inner focus type lens, the values of the focal length "f (= f ')" and the lens thickness "T" change depending on the photographing distance "R".
(= F ′) ”, and accurate calculation of the image blur amount cannot be performed simply by storing the values of the lens thickness“ T ”.

By the way, in the case of an inner focus lens (a type called a single focus inner focus lens), if the shooting distance "R" is determined, the focal length "f (= f ')" in the shooting state,
When the lens thickness “T” and the focal length “f (= f ′)” are determined, “b” is also uniquely determined.

Therefore, if the rotational position of the lens distance ring can be detected, and the accurate values of "T" and "b" corresponding to the detection result can be used for the sequential calculation, the above-mentioned (Equation 4) is used each time. , The variables "b", "R", and "a" are determined, so that accurate calculation of the image blur amount can be performed.

The focus position detecting section 7 described with reference to FIG. 1 is provided for this purpose, and outputs the rotation position information of the focus cam ring to the second MCU 4. The second MCU 4 stores a correspondence table between the focus position and the values of “b”, “R”, and “a” described above, and can be used for calculating the image blur amount.

Next, determination of another variable term “n” in the above (Equation 4) will be described below.

That is, regarding the above-mentioned shake of the photographing apparatus, camera shake may be considered. It is experimentally confirmed that the rotation center of the shake at this time is different when the total weight of the camera body 1 and the lens barrel 2 is small and large.

Here, in the former case, the camera body 1
However, since the rear end of the camera body 1 is not largely displaced because the eyepiece comes into contact with the face of the photographer, the rotational vibration of the photographing apparatus is set to be around the body eyepiece as the rotation center. Rotation runout is likely to occur.

In the latter case, since the weight is large,
In many cases, the center of rotation occurs at the position of the center of gravity including the camera body 1 and the lens barrel 2.

Therefore, if the weight and the position of the center of gravity of the camera body 1 and the lens barrel 2 can be determined, the rotation center position of the optical axis of the photographing apparatus can be specified.

Here, assuming that the weight of the camera body 1 is Wc, the position of the center of gravity from the film surface is Lc, the weight of the lens barrel 2 is Wl, and the position of the center of gravity from the film surface is Ll,
The relationship between the overall center-of-gravity position Lt of the camera body 1 and the lens barrel 2 is represented by the following (Equation 7).

That is, (L1−Lt) × Wl = (Lt−Lc) × Wc (Expression 7)

From this (Equation 7), the total barycentric position Lt is as follows: Lt = (L1 × W1 + Lc × Wc) / (Wc + W1) (Equation 8)

Here, when the total weight (Wc + Wl) of the camera body 1 and the lens barrel 2 is small, since the center of rotation is close to the eyepiece, n = 0 and (Wc + Wl).
When Wl) is large, n = L by setting the total center of gravity of the camera body 1 and the lens barrel 2 as the rotation center.
Let it be t.

Finally, the variable term “d” in (Equation 4)
The determination of “θ” will be described.

First, the second MCU 4 detects the angular velocity signal output from the angular velocity detector 5, and the second MCU 4
The angular velocity “ω” of the rotational shake may be calculated using the angular velocity signal intensity and the conversion coefficient of the angular velocity value stored in advance.

Here. The first MCU 2 serving as the CPU unit of the camera body 1 performs the above-described angular velocity signal detection operation at certain time intervals (every dt time).

Therefore, "dθ" may be calculated by the following calculation. dθ = ω × dt (Equation 9)

As described above, all the variables used in the above (Equation 4) are determined, and the shift drive amount ds (dθ) in the correction optical system with the optical axis change amount dθ can be calculated.

In the above description, the shift drive amount ds (dθ) in the correction optical system for the shake in which the change amount of the optical axis in the photographing apparatus is dθ is calculated. However, the inclination of the optical axis in the photographing apparatus is calculated. , That is, the shift drive speed of the correction optical system with respect to the angular speed “ω” of the rotational shake (expressed as ds ′ (ω))
The same equation as the above (Equation 4) can be used also for.

Ds ′ (ω) = b × ω × (R−n) / a (Equation 10)

Then, in general, it is as follows as in the above (Equation 5). ds ′ (ω) = C × b × ω × (R−n) / a (C: constant) (Equation 11)

FIG. 4 is a flowchart for explaining the operation sequence of the second MCU 4 relating to the image blur correction in the apparatus of this embodiment shown in FIG. Here, the calculation of the image blur correction amount is based on the various equations described with reference to FIG.

First, in step (hereinafter abbreviated as S) 200, information on the weight Wc of the camera body 1 and the position of the center of gravity Lc is communicated from the first MCU 2 to the second MCU 4 via the contact 8.

In step S201, a position detection signal of the focus adjustment optical system is input from the focus position detection unit 7 to detect the current lens state.

Further, in S202, the above-described S2
In response to the signal input at 01, the photographing distance "R", the distance "a" between the photographing object and the photographing optical system / lens front principal plane (H), the photographing optical system / lens rear principal plane (H ') Each value of the distance “b” between the imaging points is selected from the numerical values stored in advance in the second MCU 4 and used as the numerical value used for the calculation.

In S203, the angular velocity detector 5
Is detected, and the angular velocity “ω” of the rotational shake is calculated using the angular velocity signal intensity and the angular velocity value conversion coefficient stored in the second MCU 4 in advance.

Further, in step S204, the optical axis change amount “dθ” due to the rotational shake of the photographing apparatus at a predetermined time is calculated. Here, the second MCU 4 performs the angular velocity signal calculation operation in S203 at every predetermined time (every dt time).
“Dθ” is calculated by dθ = ω × dt, as described in the above-described equation (11).

Next, in S205 and subsequent steps, the rotation center of the rotational shake of the photographing device is detected.

First, in S205, the weight Wc and the center of gravity Lc of the camera body 1 obtained in S200 and the weight Wl of the lens barrel 2 stored in advance in the second MCU 4 are calculated.
The total weight Wt (= Wc + Wl) and the center of gravity Lt of the camera body 1 and the lens barrel 2 are obtained from the center of gravity Ll.

If the total weight Wt is larger than the predetermined value in S206, n = Lt is set (S207), and if the total weight Wt is smaller, n = 0 (S208).

Further, in S209, the image blur correction drive amount is calculated by using (Equation 4) described above with reference to FIG. 3 (using (Equation 5) as a general solution).

Thereafter, the flow advances to S210, in which the image blur correction drive unit 6 is controlled to shift-drive the image blur correction optical system.

After completing the above, the procedure returns to S201, and
The routines 201 to S210 are constantly repeated while the image blur correction drive is performed.

As is apparent from the above description, according to the image shake correcting photographing apparatus of the present embodiment, the photographing distance "R" is calculated from the lens state, and the distance between the photographing object and the photographing optical system / lens front main plane (H). , And each value of the distance “b” between the imaging optical system and the lens rear main plane (H ′) to the imaging point, and further, if necessary, the rotation center point N to the imaging point. By specifying the distance “n”, the image shake amount can be calculated more accurately from the detected rotational shake angle “dθ” of the photographing device, and the image shake correction drive capable of accurately correcting the image shake amount is possible. Becomes

The present invention is not limited to the structure of the embodiment described above, and it goes without saying that the shape, structure and the like of each part of the image blur correction photographing apparatus can be appropriately modified and changed.

For example, in FIG. 1 described above, only the vertical angular velocity detecting section and the image blur correction driving section are shown, but the apparatus of the present embodiment can be similarly applied to the horizontal direction (in the figure, the direction perpendicular to the paper). What is clear is clear. Further, it goes without saying that such a combination of two vertical and horizontal directions may be used.

[0080]

As described above, according to the image blur correcting photographing apparatus according to the present invention, the image pickup means, the photographing optical system, the image blur correcting optical system which is a part of the photographing optical system, the screen, and Image blur correction driving unit for relatively shifting the image for image blur correction, angle change detecting means for detecting an angle change of the optical axis of the photographing apparatus, state detecting means of the photographing optical system, and the angular change A camera body comprising an image blur correction drive control unit for controlling the drive of the image blur correction drive unit in accordance with the output from the detection means and the output from the state detection means; The center of gravity and the weight of the lens barrel are stored, and the center of rotation of the camera body and the lens barrel as a whole in the combined state is determined based on the stored information to determine the rotational center position. Since it based on the determined and configured to perform drive control of the image blur correction driving unit by said image shake correction drive control unit exhibits the following excellent effects.

That is, according to the present invention, each characteristic value (focal length: f (= f ′)) of the photographing optical system is detected by detecting the state of the photographing optical system in the photographing apparatus which changes depending on the photographing state. , The optical lens thickness: T, the distance between the principal plane H ′ on the rear side of the lens and the imaging plane: b, etc.), and the image blur amount can be calculated using these values. , It is possible to calculate an accurate image blur amount, and a highly accurate image blur correction drive becomes possible.

Further, according to the present invention, based on the information on the weight and the position of the center of gravity of the camera body and the lens barrel constituting the photographing apparatus, it is assumed that the camera body and the lens barrel are combined in any position. In addition, it is possible to specify the rotation center position of the optical axis with respect to this, so that it is possible to remove the image blur due to the rotation of the imaging device, and also to determine the rotation center position of the imaging device and the imaging lens optical system. It is also possible to remove the influence caused by the movement at the entrance of the system, and as a result, to calculate the image shake amount more accurately, and to perform the image shake correction drive with high accuracy.

According to the image blur correction photographing apparatus of the present invention, the camera body stored in the first storage means is provided.
Information about the weight of the camera body and the center of gravity
A lens including a position and stored in the second storage means
The information on the weight of the lens barrel is the weight of the lens barrel and the center of gravity.
Since it includes the position, the effects described above can be further exhibited,
Accurate image shake amount calculation is performed, and high-precision image shake correction driving can be performed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an entire camera suitable for applying the present invention, showing an embodiment of an image blur correction photographing apparatus according to the present invention.

FIG. 2 is a block diagram for explaining a main configuration of the image blur correction photographing apparatus according to the present invention.

FIG. 3 is an explanatory diagram for explaining a relationship between a shake (change in the angle of an optical axis) of the photographing apparatus and an image shake of a subject image in the image shake correcting photographing apparatus according to the present invention.

FIG. 4 is a flowchart for explaining an operation sequence regarding image blur correction in the image blur correction photographing apparatus according to the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 camera body 2 camera-side CPU (first MCU; including first storage unit) 3 lens barrel 4 lens-barrel side CPU (second MCU; including second storage unit) 5 angular velocity detection unit 6 image blur correction drive unit 7 Focus position detector 8 Electric contact

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Claims (3)

(57) [Claims] 1. An image pickup means, a photographing optical system held by a lens barrel constituting a photographing device, and a part of the photographing optical system and a screen are relatively shifted for image blur correction. An image blur correction driving unit, an angle change detecting unit that detects an angle change of an optical axis of the photographing device, and information on a weight of a camera body constituting the photographing device.
Information from the first storage means and, a second storage means for storing information relating to the weight of the lens barrel, these first storage means and second storage means for storing the broadcast
Based on, determine the rotation center of the image blur when the combination of a camera body and a lens barrel constituting the imaging device
Rotation center determining means to determine the output from the angle change detecting means and the rotation center determining means
And an image blur correction drive control unit that drives and controls the image blur correction drive unit based on the output from the image blur correction driving unit. 2. The image blur correction photographing apparatus according to claim 1, wherein the weight of the camera body stored in said first storage means is reduced.
Information about the camera body weight and the position of the center of gravity.
And a lens barrel stored in the second storage means.
Information on the weight is obtained from the weight of the lens barrel and the position of the center of gravity.
And an image shake correction photographing apparatus. 3. The image blur correction photographing according to claim 1 or 2.
In the device, the camera body and the lens barrel that constitute the photographing device are combined
Calculation means for calculating the total weight when the
The rotation center is determined based on the output means.
Image shake correction photographing device.