JPH07261221A - Image blur prevention device - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain an image blur prevention device capable of highly accurately correcting image blur caused by vibration. [Structure] The blurring of the photographing optical system is detected by the blurring detecting means,
When the blurring correction means corrects the blurring of the image by the photographing optical system from the blurring signal from the blurring detecting means and the blurring correction coefficient stored in the correction coefficient changing means provided in a part of the photographing optical system, The correction means obtains the shake correction coefficient from the correction coefficient changing means based on the focal length information of the photographing optical system, and the correction coefficient changing means calculates the initial value of the shake correction coefficient by
The value should be set to the value when the photographing optical system is on the longest focal length side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image blur prevention device,
For example, it is suitable for an interchangeable lens for a single-lens reflex camera, which is capable of highly accurately correcting an image blur caused by vibration of a camera shake.

[0002]

2. Description of the Related Art Generally, when a camera is held by hand for shooting, when the camera vibrates due to camera shake or the like, image blurring occurs in a captured image and the image quality deteriorates. For this reason, recently, various cameras have been proposed which have an image blur prevention device for correcting an image blur caused by vibration such as camera shake.

An image blur prevention device is generally composed of a sensor section for detecting the vibration of a camera (photographing optical system) and a correction control section for making a correction according to a signal from the sensor section so as not to cause an image blur. ing.

For example, camera shake vibrations (normally, tilt vibrations about two axes perpendicular to the photographing optical axis) are detected by a sensor unit as acceleration signals, velocity signals, or displacement signals, and these signals are processed by a signal processing system. If necessary, perform integration to convert it into a displacement signal or velocity signal, and depending on the converted signal, drive the optical system in the vibration suppression direction, or in the case of video, perform vibration by electrical processing. I try to suppress.

In the case of performing optical correction, the correction control unit used is one configured to swing (shift) the optical system in the radial direction or rotate (tilt) about two axes perpendicular to the photographing optical axis. This constitutes a feedback system control mechanism for suppressing the vibration of the image formed.

When such an image blur prevention device is applied to a single-lens reflex camera, the image blur prevention device is built in the interchangeable lens side or extends between the camera body and the lens, or an extender adapter or the front surface of the lens. It is in the form of an adapter that can be attached to.

FIG. 10 shows an example of such an image stabilizing apparatus. In FIG. 10, reference numeral 1 denotes an angular accelerometer, which detects and outputs an angular acceleration around the axis orthogonal to the photographing optical axis of the imaging system 4 due to camera shake as an angular acceleration signal Sa. This angular acceleration signal Sa is the first integrator 2
Are integrated into the velocity signal v by the second integrator 3 and converted into the displacement signal d by the second integrator 3. 5 is an actuator,
The imaging system 4, which is provided so as to be movable in the radial direction for image stabilization, operates so as to be controlled in the radial direction by inputting the displacement signal d.

Reference numeral 6 denotes a position detecting means, which comprises a variable resistor for detecting the actual displacement of the image forming system 4. The signal from the position detecting means 6 is fed back to the input system of the actuator 5 to form a local feedback loop which makes the driving amount of the imaging system 4 correspond to the vibration displacement. Reference numeral 7 denotes an operational amplifier, which is provided between the integrator 3 and the actuator 5.

Generally, the image blur amount yI when the camera is tilted by an angle θ due to vibration or the like is calculated by taking the focal length of the photographing system 4 as f
If the imaging magnification (lateral magnification) at that time is β, then yI = f · θ (1 + β) (1)

Now, assuming that the parallel decentering amount of the lens group (correction optical system) for correcting the image blur amount is yL, the sensitivity S as the image stabilizing means is S = yI / yL. 2)

As is clear from the equations (1) and (2), the sensitivity S of the image stabilizing means depends on the focal length f and the imaging magnification β of the photographing system, that is, the focus distance.

That is, in order to obtain an appropriate image blur prevention effect, it is necessary to obtain the decentering amount of the correction optical system by using an appropriate sensitivity according to the focal length and the focal length.

The applicant of the present invention has already proposed a solution to this problem in Japanese Patent Laid-Open No. 4-301828. According to this, the zoom position sensor and the focus position sensor of the variable magnification optical system are provided, and the image stabilization sensitivity is calculated based on the output of each sensor, or the appropriate image stabilization sensitivity stored in the ROM is detected. The degree of eccentricity of the correction optical system is obtained by using the degree.

In a single-lens reflex camera, the image taken on the film surface and the image observed by the finder are obtained through the same taking lens. Therefore, if an image stabilizing device is incorporated in the taking lens, only during the exposure period. Not only that, the image stabilization effect can be obtained even when the composition is determined.

However, if the image stabilization effect is to be obtained even when the composition is determined, the power consumption increases as compared with the case where the image stabilization apparatus operates only during the exposure. Therefore, when power is supplied to the image stabilization device from the camera body side, a situation may occur in which the power supply in the body is quickly consumed. Therefore, when power is supplied from the power supply on the body side, the power consumption of the image stabilization device causes a problem in that shooting cannot be performed at all due to power consumption when actually shooting.

The present applicant has proposed a solution to such a problem in Japanese Patent Laid-Open No. 4-301825.

In the publication, a dedicated power source for supplying power only to the image stabilizing device is provided on the lens side including the image stabilizing device, separately from the power source in the main body of the image taking apparatus.

The power required for zooming, focusing, and diaphragm driving during photographing is supplied from the body side, and the power inside the lens is used only for the operation of the image stabilizing device. For this reason, even if the power inside the lens is consumed due to the image stabilization device, zooming, focusing, and diaphragm drive, which affect shooting, are operated by the power supply on the body side, making shooting impossible. There is no. Also,
Even if the power inside the lens is turned off or the power is removed from the lens when the image stabilizer is not used, zooming, focusing, and
Since the diaphragm drive is performed by the power supply on the body side, it has the feature that it does not hinder shooting.

[0019]

Recently, an automatic focusing (AF) camera has become the mainstream as a single-lens reflex camera. In the TTL passive method currently used in many AF single-lens reflex cameras, the focal length information and the focus information are used in the same manner as the image blur prevention operation in order to accurately perform the AF calculation. For this reason, a focal length detection encoder and a focus information detection encoder are built in the lens, and the information necessary for AF calculation is read from the information of these encoders from a table on the ROM in the lens microcomputer and the information is read. It is transmitted to the body side for AF calculation.

On the other hand, as described above, in order to use the optimum image stabilization sensitivity, the focal length of the optical system and focus information are required.

However, if an independent focal length detecting encoder and focus information detecting encoder are provided for the image blur prevention operation, the entire apparatus becomes complicated and large. For this purpose, for example, it is desirable that the focal length detecting encoder for AF also serves as the focus information detecting encoder. However, as described above, in the case of a system in which an independent power source is provided for image blur prevention operation and power is supplied from the body side for operations such as focus, aperture, and zoom, AF information is necessary for focus operation. Since the information is indispensable at the time of shooting, it is necessary to supply power to the encoder from the body side.

Therefore, if the power supply from the power source on the body side is stopped for some reason, the image blur prevention device can obtain the necessary focal length information and focus information regardless of having an independent power source. In some cases, the appropriate image blur prevention operation cannot be performed.

This becomes a problem particularly during the development period of the image blur prevention device incorporated in the interchangeable lens for a single-lens reflex camera.
Because, the system that receives power from the power supply on the body side (hereinafter,
The conventional lens system) and the image blur prevention device system are circuit systems that are independent of each other, including the power supply, and are optical systems that affect the performance of the image blur prevention device even though they are originally developed separately. Since the system focal length information and focus information read parts depend on the conventional lens system, the image stabilization function of the image stabilization device must be completed if at least the conventional lens system focal length information and focus information read parts are not completed. This is because it is difficult to measure the characteristics of.

Similarly, even in the inspection stage during production, the characteristics of the image blur prevention system alone cannot be measured, and the conventional lens system must be used.
It is necessary to perform the test by supplying power to both the image blur prevention system.

According to the present invention, even if the focal length information and the focus information of the photographing system cannot be obtained because the lens system is not energized, the initial value of the image stabilization sensitivity is appropriately set in advance, and An object of the present invention is to provide an image blur prevention device that can effectively prevent image blur even if the focal length information or the focus information cannot be read by using the set value.

[0026]

According to the image blur prevention device of the present invention, (1-1) blurring of a photographing optical system is detected by a blurring detecting means,
When the blurring correction means corrects the blurring of the image by the photographing optical system from the blurring signal from the blurring detecting means and the blurring correction coefficient stored in the correction coefficient changing means provided in a part of the photographing optical system, The correction means obtains the shake correction coefficient from the correction coefficient changing means based on the focal length information of the photographing optical system, and the correction coefficient changing means calculates the initial value of the shake correction coefficient by
It is characterized in that it is set to a value when the photographing optical system is on the longest focal length side.

(1-2) The blur detection means detects the blur of the photographing optical system, and the blur signal from the blur detecting means and the blur correction coefficient stored in the correction coefficient changing means provided in a part of the photographing optical system. Therefore, when the blurring of the image by the photographing optical system is corrected by the blurring correcting means, the blurring correcting means obtains the blurring correction coefficient from the correction coefficient changing means based on the focus information of the photographing optical system. The correction coefficient changing means is characterized in that the initial value of the blur correction coefficient is set to a value when the photographing optical system is focused on an object at infinity.

(1-3) The blurring of the photographing optical system is detected by the blurring detecting means, and the blurring signal from the blurring detecting means and the blurring correction coefficient stored in the correction coefficient changing means provided in a part of the photographing optical system. Therefore, when the blurring of the image by the photographing optical system is corrected by the blurring correcting means, the blurring correcting means obtains the blurring correction coefficient from the correction coefficient changing means based on the focus information of the photographing optical system. The correction coefficient changing means is characterized in that the initial value of the blur correction coefficient is set to a value at which the photographing optical system focuses on a distance of a predetermined multiple of the focal length.

In particular, the value of a predetermined multiple of the focal length is set to 35 or 50.

(1-4) The blurring of the photographing optical system is detected by the blurring detecting means, and the blurring signal from the blurring detecting means and the blurring correction coefficient stored in the correction coefficient changing means provided in a part of the photographing optical system. Therefore, when correcting the blur of the image by the photographing optical system by the blur correcting unit, the blur correcting unit obtains the image blur correction coefficient from the correction coefficient changing unit based on the focal length information of the photographing optical system, and When an abnormality signal is output from the abnormality detecting means for detecting whether or not there is an abnormality in the detection of the focal length information of the photographing optical system, the shake correction coefficient is obtained from a predetermined value preset in the correction coefficient changing means. Is characterized by.

In particular, the predetermined value preset in the correction coefficient changing means is a blur correction coefficient when the photographing optical system is on the long focus side.

(1-5) The blurring of the photographing optical system is detected by the blurring detecting means, and the blurring signal from the blurring detecting means and the blurring correction coefficient stored in the correction coefficient changing means provided in a part of the photographing optical system are stored. From this, when correcting the blurring of the image by the photographing optical system by the blurring correction means, the blurring correction means obtains the image blurring correction coefficient from the correction coefficient changing means based on the focus information of the photographing optical system, and When an abnormality signal is output from the abnormality detecting means for detecting the presence or absence of abnormality in the detection of focus information of the photographing optical system, the blur correction coefficient is obtained from a predetermined value preset in the correction coefficient changing means. I am trying.

Particularly, the predetermined value preset in the correction coefficient changing means is a blur correction coefficient when the photographing optical system is focused on infinity, and the predetermined value preset in the correction coefficient changing means is the above-mentioned It is characterized in that it is set to a value that is focused on a distance that is a predetermined multiple of the focal length of the photographic optical system.

[0034]

Embodiment 1 FIG. 1 is a block diagram of the essential parts of Embodiment 1 of the present invention.

In FIG. 1, reference numeral 8 denotes an interchangeable lens body, which is composed of a zoom lens and is an image blur prevention device 14 of the present invention.
Built in. The image blur prevention device 14 includes a blur prevention control unit 12 that performs a blur prevention operation, and the blur prevention control unit 1.
It has a blur prevention CPU 13 that manages the start and stop of the second operation.

The blur prevention control unit 12 includes a blur detection sensor (blurring detection means) 9 for detecting blurring of a photographing system or a camera.
A signal processing system 10 for performing feedback control based on a signal from the blur detection sensor 9, and a signal processing system 10
It has an anti-shake drive system 11 that actually performs an anti-shake operation by a control signal from These are respectively shown in Figure 1.
The blur detection sensor 9 corresponds to the angular accelerometer 1, and the signal processing system 10 is the same as the integrators 2 and 3, the position detection means 6, and the operational amplifier 7.
Equivalent to. The anti-shake drive system 11 also corresponds to the imaging system 4 and the actuator 5. Anti-shake drive system 1
1 and the blur prevention CPU 13 constitute an element of blur correction means. Further, the blur prevention CPU 13 includes a correction coefficient changing unit.

In the interchangeable lens body 8, a power source 15 in the lens is provided.
Is built in. As the power source, for example, a camera lithium battery, an alkaline manganese dry battery, a Ni-Cd dry battery, or the like can be used.

Power is supplied to the image blur prevention device 14 from the in-lens power supply 15.

Reference numeral 16 denotes a lens CPU, which receives communication from the body side (camera body) 22 through communication contacts 21c and 21d, and the focus drive system 17, the zoom drive system 18, the aperture drive system 19 and the like depending on the command value. It is working. Further, the lens CPU 16 controls the state inside the lens body (zoom position, focus position, state of aperture value, etc.), information on the lens (open aperture value, focal length, distance measurement data, etc.), and focal length detection encoder. 30 and the lens focal length information obtained from the focus distance detection encoder 31 and the information necessary for the AF calculation performed by the CPU 27 in the body from the focus information, are selected from the internal ROM table, and the communication contact 21c,
21e is transmitted to the body side. Contact point 2 for communication
Reference numeral 1c is a clock line contact for serial synchronization called LCLK, which is necessary for communication sent from the body 22 side. The contact 21d is a body 22 called DCL.
It is a contact for a data line sent from the side to the lens 8 side. Reference numeral 12e is called a DCL, and is a data line contact sent from the lens 8 side to the body 22 side. Here, the communication is performed by synchronous clock type serial communication of 8-bit data.

The focus drive system 17 includes the lens CPU 1
The focus adjustment lens is driven according to the command value from 6 to perform focusing. The zoom drive system 18 drives the lens barrel so as to change the focal length of the lens according to a command value from the lens CPU 16 or when a switch (not shown) is pressed. Aperture drive system 19
Performs an operation of stopping down the diaphragm to a set position or returning to the open state according to a command value from the lens CPU 16.

Lens CPU 16, focus drive system 1
7, the zoom drive system 18, the diaphragm drive system 19, the focal length detection encoder 30, and the focus distance detection encoder 31 constitute an in-lens electrical system 20. For the electrical system 20 in the lens, the mount portion Vdd contact 2
Power is supplied from the in-body power supply 29 through the 1a and GND contacts 21b.

Inside the camera body 22, the photometric unit 2
3, distance measuring unit 24, shutter 25, feeding charge system 2
6 and body C for managing the start and stop of these operations, exposure calculation, AF calculation, communication with the lens, etc.
An in-body electrical system 28 having a PU 27 is built in. The in-body electric system 28 is also supplied with power from the in-body power supply 29.

The anti-shake CPU 13 electrically connects both encoders so that focal length information and focus distance information can be obtained from the focal length detection encoder 30 and the focus distance detection encoder 31, respectively, for the optimum anti-shake operation. Connected.

From the focal length detecting encoder 30, a digital signal obtained by dividing the zoom range from the focal length on the widest side to the focal length on the telephoto side in finite steps is obtained.

From the focus distance detecting encoder 31, a digital signal obtained by dividing the focus distance from the closest side to infinity in finite steps is obtained.

Next, a method of obtaining the image stabilization sensitivity from the focal length information and the focus distance information will be described with reference to FIG.

In FIG. 2, the vertical axis represents zoom position division, and the horizontal axis represents focus distance division. In the present embodiment, the operations for zoom position division and focus distance division are each made up of a switch made up of four brushes, and it is possible to perform 256-step division as a whole. The table in the figure shows the image stabilization sensitivity (S0, 0 → S15, 15) at each position of zoom position division (Z0 → Z15) and focus distance division (A0 → A15), and the image blur prevention CPU 13 It is stored in the ROM as a value peculiar to the photographing system.

Now, when the zoom position of the photographing system is Zm and the focus distance is An, the image stabilization sensitivity Smn is the image blur prevention C
The image stabilization sensitivity Smn read out from the ROM by the PU 13 determines the eccentricity amount of the correction optical system driven for the image blur correction based on the image blur signal detected by the image blur detection sensor 9. In this way, the amount to be operated according to the focal length of the shooting system and changes in the focus distance,
That is, the image stabilization sensitivity is changed to obtain a stable image on the imaging surface.

In the present embodiment, since the image stabilization sensitivity changes stepwise, a slight error may occur in the image stabilization sensitivity, but the error in zoom division and focus division at that time is within the allowable value. It is divided into

Next, the connection between each encoder, the blur prevention CPU 13 and the lens CPU 16 will be described with reference to FIG.

FIG. 3 shows a focal length detection encoder 30 and
Focus distance detection encoder 31 and blur prevention CPU 1
3 is an explanatory diagram of a connection relationship with the lens CPU 16. FIG.

The focal length detection encoder 30 shown in the figure divides from the short focal length side to the long focal length side into 16 parts, and the focal length information is output as a 4-bit signal as in the case of FIG. I am configuring. The focus distance detection encoder 31 also divides the distance from the near side to the infinity side into 16 parts, and outputs a 4-bit signal as the focus distance information.

As shown in the figure, each encoder has a pattern formed on the substrate by a method such as vapor deposition, and a set of brushes moves this pattern in the vertical direction in the figure in accordance with zooming. A signal corresponding to the distance section or the focus distance section is output. In the figure, for the focal length detection encoder 30, the upper side is for the telephoto side pattern, the lower side is for the wide angle side pattern, and for the focus distance detection encoder 31, the upper side is for the infinity side,
The lower part is the closest side.

There are one brush 33 on each of the four signal patterns on the focal length detection encoder 30, and they are connected to the input ports IPL0 to IPL3 of the lens CPU 16, respectively. These input ports are pulled up inside the CPU. There is also one brush for the GND pattern, which is connected to the output port OPL0 of the lens CPU 16. Similarly, in the focus distance detection encoder 31, there is one brush 34 on each signal pattern, and the input port IPL of the lens CPU 16 is provided.
4 to IPL7, and the GND pattern brush is connected to the output port OPL1.

These signals are also connected to the blur prevention CPU 13 via the buffer 32. Lens CPU1
The signals connected to the input ports IPL0 to IPL3 of the CPU 6 are the input ports IPS of the blur prevention CPU 13 respectively.
0 to IPS3, and similarly IPL4 to IP
Signals connected to L7 are input port IP
It is connected to S4 to IPS7. The signals connected to the output ports OPL0 and OPL1 of the lens CPU 16 are the input ports IPS of the blur prevention CPU 13 respectively.
8, IPS 9 is connected.

The buffer 32 is used by the blur prevention CPU 13 and the lens CPU 16 as separate power sources. For example, in a state where the image blur prevention system is powered off and only the lens system is powered on, if there is no buffer 32,
When an H level signal is output from the pull-up of the input port on the lens CPU 16 side or the output port, current flows into the blur prevention CPU side. Buffer 3
2 is for preventing this, and uses a CMOS inverter such as 4050UB.

Next, the operation of this embodiment will be described.

FIG. 4 is a flow chart for explaining the operation procedure of the focal length information and the routine for reading the focus distance information in the in-lens CPU 16 of the first embodiment.

The focus distance information and the routine for reading the focus distance information is one of the routines sequentially executed in a loop in the main routine of the lens CPU 16. Alternatively, it may be called by a timer interrupt at regular time intervals.

When this routine is executed, first, at step 100, the L level is output from the output port OPL0.

Then, in step 101, a very short weight is set in anticipation of the stable time of switching, and then in step 102, the input ports IPL0 to IPL0 to IPL are input.
Read L3. At this time, when the brush 33 is positioned on the pattern, the L level (= 0) is read,
When it is outside the pattern, H level (= 1) is read. This 4-bit signal becomes the focal length information.

In the above, the output port OPL0 is
Play the role of ND. Thus, the reason why the output port OPL0 is set to the L level only at the time of reading information is to reduce the power consumption at any time other than the time of reading information.

Next, at step 103, the output port O
The H level is output from PL0.

Next, the focus distance information is read out. The sequence is the same as the case of reading the focal length information.

In step 104, the output port OPL
The L level is output from 1.

Next, after waiting at step 105, at step 106 the input ports IPL4 to IPL
Read L7. This 4-bit signal becomes the focus distance information.

Next, at step 107, the output port O
The H level is output from PL1.

By the above operation, the focal length information and the focus distance information are fetched into the lens CPU 16 and are used for transmitting them to the camera body 22 as the focal length information and for obtaining the necessary AF information. .

Next, referring to FIG. 5, the blur prevention C of the first embodiment
The operation procedure of the routine for reading the focal length information and the focus distance information in the PU 13 and obtaining the image stabilization sensitivity based on the information will be described.

This focal length information and the routine for reading the focal length information is one of the routines sequentially executed in the loop in the main routine of the in-lens CPU 16. Alternatively, it may be called by a timer interrupt at regular time intervals.

The blur prevention CPU 13 is the in-lens CPU 1
Similarly to 6, the focal length information and the focus distance information are read from the focal length detection encoder 30 and the focus distance detection encoder 31. The GND line of these encoders is controlled by the lens CPU 16 as described above. Therefore, the blur prevention CPU 13
Then, the GND line is monitored and the focal length information and the focus distance information are read out only when the GND line falls to L.

Next, the operation of the blur prevention CPU 13 will be described in more detail.

First, when this focal length and focus distance reading routine are called, step 200
In, the input port IPS8 is read and the process proceeds to step 201. When the input port IPS8 is at the L level, it indicates that the lens CPU 16 is reading the focal length information. In this case, since the focal length information can be read, the process proceeds to step 202 and the input ports IPS0 to The focal length information is read from the IPS3.

Next, at step 203, the flag FRDFLG indicating that the focal length information has been read is set to 1. FRDFLG is used after the power is reset after the in-lens power supply 15 is replaced, or when the image stabilization operation is not required for a long time because the image stabilization CPU 13 reduces the power consumption.
It is initialized to 0 when the clock is stopped, the sleep state is entered, and then the operation is started by a start request or the like.

Then, the process proceeds to step 206 to read the focus distance information. If the input port IPS8 is at the H level in step 201,
The lens CPU 16 is not reading the focal length information, and the GND line of the focal length detection encoder 30 is not at the L level, so the focal length information cannot be read. For this reason, the read operation is not performed and step 2
Go to 04.

In step 204, whether the focal length has been read by the blur prevention CPU 13 until now is checked by comparing whether FRDFLG is 1 or not.

When FRDFLG is 1, the focal length information has been read from the focal length detection encoder 30, so the previously read data is used as the focal length information and nothing is done. Go to step 206.

If FRDFLG is not 1, it indicates that the focal length information has not been read up to this point. Therefore, in step 205, the value on the long focal length side is set as the initial value of the focal length information. The reason why the value on the long focus side is set is that the effect of blurring on the image is greater on the long focus side, and thus the blurring prevention effect is also required to be stronger on the long focus side. Then, the process proceeds to step 206.

Steps 206 to 211 are portions for reading the focus distance information, and the basic flow is the same as the portion for reading the focal distance information from steps 200 to 205 except that the focal distance information is changed to the focus distance information. Is the same. In step 206, input port I
After reading PS9, the process proceeds to step 207. When the input port IPS9 is at the L level, it indicates that the lens CPU 16 is reading the focus distance information. In this case, since the focus distance information can be read, the process proceeds to step 208, and the input port IPS4
~ Read focus distance information from IPS7.

Next, at step 209, the flag FOCRDFLG indicating that the focus distance information has been read is set to 1. FOCRDFLG is set to be initialized to 0 at the same timing as FRDFLG. Then proceed to step 212.

In step 207, the input port IPS
When 9 is at the H level, the lens CPU 16 is not reading the focus distance information, and the GND line of the focus distance detection encoder 31 is not at the L level, so the focus distance information cannot be read. For this reason, the read operation is not performed, and step 210 is performed.
Proceed to.

In step 210, whether or not the focus distance information has been read by the blur prevention CPU 13 has been checked by comparing whether FOCRDFLG is 1 or not.

When FOCRDFLG is 1, the focus distance information has been read from the focus distance detection encoder 31. Therefore, the previously read data is used as the focus distance information, and nothing is done. Go to step 212.

If FOCRDFLG is not 1, it indicates that the focus distance information has not been read up to this point. Therefore, in step 211, a value of infinity is set as the initial value of the focus distance information. The value set to the infinity side is effective for preventing image blur at long seconds, and in such cases, subject blur will be large for short-distance subjects such as people, so shooting of distant subjects such as landscapes This is because it is supposed to be used more.

Then, the process proceeds to step 212.

In step 212, the anti-shake sensitivity is obtained from the focal length information and the focus distance information obtained as described above as described with reference to FIG. The data is stored in a predetermined address in the RAM of the CPU 13, the operation of the above routine is completed, and the process returns to the main routine. In the shake correction amount calculation routine called from the main routine, the correction optical system drive amount is calculated using this image stabilization sensitivity.

As described above, in this embodiment, even when the lens system is not energized and the focal length information and the focus distance information cannot be read on the image blur prevention system side, the blur prevention effect is most desired. By setting the initial values on the long focus side and the infinity side where there are more opportunities for shooting, an effective blur prevention effect is obtained.

It should be noted that the call cycles of the focal length information and focus distance information reading routines by the blur prevention CPU 13 and the lens CPU 16 are intentionally not synchronized so that the blur prevention CPU 13 cannot read these information. It is set to be a cycle.

In the present embodiment, the focal length detecting encoder and the focus distance encoder are described as outputting signals of 4 bits and dividing into 16 parts, but the present invention is not limited to this mode. The number of divisions may be more or less.
When applied to a single-focus lens, the focal length detection encoder may not be provided and only the focus distance may be detected.

Further, in this embodiment, an example of the interchangeable lens configured to electrically drive the zoom is also shown.
The present invention is likewise applicable to a conversion lens in which zooming is performed manually.

Next, a second embodiment of the present invention will be described.

Conventionally, many interchangeable lenses for single-lens reflex cameras are designed to have the best performance in a state of being focused at a distance (50f) about 50 times the focal length. Further, in the actual development stage or trial production stage, the optical system is evaluated by the performance when focusing on a distance 50 times the focal length.

The second embodiment is an embodiment devised so that the evaluation at the development stage can be performed more easily. The initial value of the focus distance information of the lens is not the infinity of the first embodiment but the focal length of the taking lens. The difference is that the distance is set to 50 times.

FIG. 6 shows a blur prevention CP according to the second embodiment of the present invention.
It is a flowchart explaining operation | movement of U13. The steps assigned the same numbers as those in FIG.

In this embodiment, step 211 of the first embodiment is used.
Instead of, the step 213 is entered, and when the initial value of the focus distance information is set, it is assumed that the focus is set to 50 times the focal length instead of infinity in this step. .

Therefore, when evaluating the anti-shake system at the trial production stage, it is possible to measure at a distance where the lens performance is maximized without energizing the lens system one by one. There is.

Next, a third embodiment of the present invention will be described.

In the second embodiment, the initial value of the focus distance information is set to 50 times the focal length. The blurring prevention device is particularly effective for a telephoto lens, but when it is applied to a zoom lens whose long focal length side is about 300 mm,
At 50 times the focal length on the long focal length side, the distance is as long as 15 m, and it may be difficult to secure such a linear distance when conducting a study.

In this embodiment, the initial value of the focus distance information is set to 35 times the lens focal length instead of 50 times.

FIG. 7 shows a blur prevention CP according to the third embodiment of the present invention.
It is a flowchart explaining operation | movement of U13. The steps assigned the same numbers as those in FIG.

In this embodiment, step 213 of the second embodiment is executed.
Step 214 is included instead of, and when the initial value of the focus distance information is set, it is assumed that the focus is 35 times the focal length in this step.

Thus, even in the case of a lens system having a telephoto end of 300 mm, it is sufficient to secure a linear distance of 10 m, which is 35 times the focal length, instead of 15 m, which is 50 times the focal length. Has the advantage of improving

Next, a fourth embodiment of the present invention will be described.

In the fourth embodiment, the focal length information and the initial value of the focal length information are set to the focal length detecting encoder 30.
In this embodiment, the focus distance detecting encoder 31 is used even when an abnormality occurs during reading.

8 and 9 are flow charts for explaining the operation of the blur prevention CPU 13 according to the fourth embodiment of the present invention.
The steps assigned the same numbers as those in FIG.

Compared with FIG. 5, this flowchart has steps 220 to 223 for reading the focal length and steps 224-2 for reading the focal length.
27 is inserted.

In the present embodiment, after the focal length information is read from the input ports IPS0 to IPS3 in step 202, these input ports are read again, the values of these two times are compared, and if they match, it is correctly read. If they do not match, it means that the reading is abnormal.

When the focal length information is read in step 202, first, in step 220, this value is stored in the address FVAL1 in the memory.

Next, in step 221, the input ports IPS0 to IPS3 are read again. Then, the focal length information read in step 221 is
At 2, it is stored in the memory at the address FVAL2.

In the next step 223, FVAL1 and FV
A comparison is made as to whether the focal length information stored in AL2 matches.

If they match, it means that the data has been correctly read, so the flow advances to step 203 to set FRDFLG to 1.

If they do not match, it is judged that some abnormality has occurred, and the routine proceeds to step 205, where the initial value on the long focus side is set as the focal length information. Similarly for the focus distance information, step 2
The focus distance information read in 08 is the same as in step 2
At 24, it is stored in memory at the address FOCVAL1.

Next, in step 225, the input ports IPS4 to IPS7 are read again, and this step 2
The focus distance information read in step 25 is the step 2
At 26, it is stored at the address FOCVAL2.

In the next step 227, FOCVAL1 and
The focus distance information stored in FOCVAL2 is compared to see if they match.

If they match, the data has been read correctly, so the routine proceeds to step 208, where FOCRDFLG is set to 1.

If they do not match, step 21
Proceeding to step 1, the infinity side value which is the initial value is set as the focus distance information.

In the present embodiment, even when there is an abnormality in reading the focal length information and the focus distance information, or even when the focal length information and the focus information cannot be read, a high image stabilization is achieved due to the optimum image stabilization sensitivity. There is an effect that can be obtained.

In this embodiment, the focus distance is set to infinity as an initial value.
The focal length may be set to a predetermined value, such as double or 35 times.

The means for checking the encoder reading abnormality is not limited to the method described in this embodiment. For example, if there is a change in the value read from the encoder, compare it with the value before the change, and check whether the value set next to the value before the change has changed correctly. Good.

[0120]

As described above, according to the present invention, even if the focal length information and the focus information of the photographing system cannot be obtained because the lens system is not energized, the initial value of the image stabilization sensitivity is set in advance. To achieve an image blur prevention device capable of effectively preventing image blur even when focal length information or focus information cannot be read by appropriately setting and using the set value. You can

Particularly in the present invention, the focal length information of the optical system and the initial value of the image stabilization sensitivity based on the focus distance information are most likely to be affected by camera shake, so that the effect of the image blur prevention device is the greatest. Since it is set to, even when the lens system is not energized and the focal length information and focus distance information cannot be read, the effective image blur prevention effect on the long focus side where the image blur prevention effect is most desired is desired. There is an effect that can be obtained. At this time, the image stabilization sensitivity is set to a focus infinity with high optical performance of the lens, or the focus distance used at the time of design is set to a value that is a predetermined multiple of the focal length. Obtainable.

Further, since the initial value is set to the optimum value for the examination of the optical system, it is possible to measure the characteristics of the image blur prevention system even when the normal lens system is not completed during development. It is very effective even during the development period of the image blur prevention device.

Also, during performance inspection and characteristic measurement of the image blur prevention device, since the image stabilization sensitivity at a fixed focal length and focus distance is set as the initial value, it is possible to energize the lens system. It has the feature that the image stabilizer can be easily measured and inspected.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a focal length of a first embodiment of the present invention and a portion for obtaining a vibration isolation sensitivity from the focus distance.

FIG. 3 is a diagram for explaining a configuration of a focal length and focus distance detection unit according to the first embodiment of the present invention.

FIG. 4 is a flowchart illustrating an operation procedure of a focal length information and a routine for reading the focal length information in the in-lens CPU 16 according to the first embodiment of the present invention.

FIG. 5 is a flowchart illustrating an operation procedure of a focal length information and a focus distance information reading routine in the blur prevention CPU 13 according to the first embodiment of the present invention.

FIG. 6 is a flowchart illustrating an operation procedure of a focal length information and a focus distance information reading routine in the blur prevention CPU 13 according to the second embodiment of the present invention.

FIG. 7 is a flowchart illustrating an operation procedure of a focal length information and a focus distance information reading routine in the blur prevention CPU 13 according to the third embodiment of the present invention.

FIG. 8 is a flowchart illustrating an operation procedure of a focal length information and a focus distance information reading routine in the blur prevention CPU 13 according to the fourth embodiment of the present invention.

FIG. 9 is a flowchart illustrating an operation procedure of a focal length information and a focus distance information reading routine in the blur prevention CPU 13 according to the fourth embodiment of the present invention.

FIG. 10 is a diagram for explaining the outline of the configuration of a conventional image blur prevention device.

[Explanation of symbols]

 1 Angular accelerometer 5 Actuator 9 Blur detection sensor 10 Signal processing system 11 Blur prevention drive system 13 Blur prevention CPU 15 Lens power supply 16 Lens CPU 20 Lens electric system 30 Focal length detection encoder 31 Focus distance detection encoder

Claims (9)

[Claims] 1. A shake detection means detects a shake of a photographing optical system, and the shake signal is output from the shake signal from the shake detecting means and a shake correction coefficient stored in a correction coefficient changing means provided in a part of the photographing optical system. When the blurring of the image by the photographing optical system is corrected by the blurring correcting means, the blurring correcting means obtains the blurring correction coefficient from the correction coefficient changing means based on the focal length information of the photographing optical system. An image blur prevention device, wherein the changing means sets an initial value of the blur correction coefficient to a value when the photographing optical system is at the longest focal length side. 2. A blur of the photographing optical system is detected by a blur detecting means, and the blur signal is output from the blur signal from the blur detecting means and the blur correction coefficient stored in a correction coefficient changing means provided in a part of the photographing optical system. When correcting the blurring of the image by the photographing optical system by the blurring correction means, the blurring correction means obtains the blurring correction coefficient from the correction coefficient changing means based on the focus information of the photographing optical system, and the correction coefficient changing An image blur preventing device, wherein the means sets an initial value of a blur correction coefficient to a value when the photographing optical system is focused on an object at infinity. 3. A shake detection means detects a shake of the photographing optical system, and the shake correction coefficient stored in a correction coefficient changing means provided in a part of the shake detecting optical system is used to detect the shake. When correcting the blurring of the image by the photographing optical system by the blurring correction means, the blurring correction means obtains the blurring correction coefficient from the correction coefficient changing means based on the focus information of the photographing optical system, and the correction coefficient changing An image blur prevention device, wherein the means sets an initial value of the blur correction coefficient to a value at which the photographing optical system focuses on a distance of a predetermined multiple of the focal length. 4. A value of a predetermined multiple of the focal length is set to 35 or 5
The image blur prevention device according to claim 3, wherein the image blur prevention device is 0. 5. The blurring of the photographing optical system is detected by the blurring detecting means, and the blurring correction coefficient stored in the correction coefficient changing means provided in a part of the photographing optical system is used to detect the blurring. When correcting the blurring of the image by the photographing optical system by the blurring correcting means, the blurring correcting means obtains the image blurring correction coefficient from the correction coefficient changing means based on the focal length information of the photographing optical system, and the photographing optical system. When an abnormality signal is output from the abnormality detecting means for detecting the presence or absence of abnormality in the detection of the focal length information of the system, the blur correction coefficient is obtained from a predetermined value preset in the correction coefficient changing means. Image blur prevention device. 6. The image blur prevention apparatus according to claim 5, wherein the predetermined value preset in the correction coefficient changing means is a blur correction coefficient when the photographing optical system is on the long focus side. 7. A blur detection unit detects blurring of a photographing optical system, and based on a blur signal from the blur detection unit and a blur correction coefficient stored in a correction coefficient changing unit provided in a part of the photographing optical system, When correcting the blurring of the image by the photographing optical system by the blurring correcting means, the blurring correcting means obtains the image blurring correction coefficient from the correction coefficient changing means based on the focus information of the photographing optical system, and the photographing optical system. When an abnormality signal is output from the abnormality detecting means for detecting the presence or absence of abnormality in the detection of the focus information of the image, the image is obtained as the shake correction coefficient from a predetermined value preset in the correction coefficient changing means. Anti-shake device. 8. The image blur prevention apparatus according to claim 7, wherein the predetermined value preset in the correction coefficient changing means is a blur correction coefficient when the photographing optical system is focused at infinity. 9. The predetermined value preset in the correction coefficient changing means is set to a value focused on a distance of a predetermined multiple of the focal length of the photographing optical system. Image blur prevention device.