JP2008139640A - Imaging apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To change the correction angle of a correcting device in accordance with the focal length of the correcting device, then, to obtain a high-performance image, and also, to prevent uneasy feeling from being given to a photographer during the observation of an image to be photographed. <P>SOLUTION: The state of a first switch constituting a release switch is detected at a step S1. If the switch is in an on-state, it means photographing preparation, then, the operation advances to a step S2 where a photometry operation is performed, further, the driving amount of a focus lens is calculated, then, the operation advances to a step S4. The focus lens is driven at the step S4, and if a vibration-prevention switch is in an off state at a step S5, a pre-exposure correction angle driving amount is calculated at a step S6. The vibration-prevention drive is started at a step S7, and the operation advances to a step S8. A focus detecting operation is performed again at the step S8, and the focusing state is judged, if being focused, the state of a second switch is detected at a step S9, if the second switch is in an on-state, a focus detecting operation is performed at a step S10, and a driving amount in the midst of the exposure as the first correction value of a vibration prevention unit is calculated at a step S11. At a step 12, the vibration prevention driving value is changed to a value calculated at the step S11, a shutter is driven and the exposure is performed by an imaging element at a step S13, and an imaging operation is finished at a step S14. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an imaging apparatus equipped with an image shake correction mechanism for performing shake correction.

  Since the current camera automates all the important tasks for shooting such as determining exposure and focusing, the possibility of shooting failure even by those who are unskilled in camera operation is extremely low. In recent years, cameras that prevent shooting failures caused by camera shake have been eagerly studied, and in particular, cameras that aim to prevent shooting failures due to camera shake of the photographer are being developed and researched.

  Camera shake during shooting is normally 1 to 12 Hz as a frequency, but as a basic idea for enabling photography without image shake, camera shake due to camera shake is detected, and the detected value Accordingly, it is necessary to displace the correction lens according to the above.

  Therefore, in order to be able to take a picture with no image shake even if camera shake occurs, it is necessary to first detect the camera vibration accurately and secondly correct the optical axis change due to camera shake. It becomes.

  This camera shake detection is basically a vibration sensor that detects angular displacement, angular acceleration, angular velocity, etc., and a camera that outputs the angular displacement by integrating the output signal of this vibration sensor electrically or mechanically. This can be done by mounting the shake detection device on the camera. Then, based on this detection information, a correction mechanism that decenters the imaging optical axis is driven to suppress image blur.

  Various proposals have also been made regarding correction means and methods, and Patent Document 1 discloses an optical device that changes the drive range of the correction device in accordance with the focal length. Japanese Patent Application Laid-Open No. 2004-228561 discloses a vibration proof camera in which the correction unit is switched between exposure and non-exposure, and the correction unit at the time of exposure has higher shake correction characteristics than the correction unit other than at the time of exposure.

JP 7-294994 A JP-A-8-101421

  The above-mentioned patent document 1 is an optical device that changes the driving range of the correction unit according to the focal length, and has proposed that the driving range of the correction unit be narrowed as the focal length becomes shorter.

  In FIG. 14A, the vertical axis represents the driving range of the correction lens L, and the horizontal axis represents the focal length of the correction lens L. The drive range is a range in which the central axis of the correction lens L is driven up and down, and the drive limit is a range in which the central axis of the correction lens L can be driven. When the drive range is limited, the optical aberration can be reduced as the focal length is shortened, but the image blur correction effect is limited compared to when the focal length is long. become. Therefore, when the photographer is observing the subject to be photographed from the viewfinder, it is difficult to observe the image blur correction effect satisfactorily. When the focal length is short, the range of the image blur correction is narrowed, and the viewfinder observer is anxious. give.

  When shaking is applied to the optical device due to camera shake or the like, an operation to eliminate image shake due to shaking is performed, but the adjustment is not adjusted according to usage conditions or shooting conditions. There is a risk of increasing deterioration. Therefore, image blur correction according to various conditions is required.

  The correction amount of the image plane with respect to the driving amount of the correction device, that is, the anti-vibration sensitivity varies depending on the optical characteristics based on the focus change such as zoom and focus. In general, the shorter the focal length, the higher the image stabilization sensitivity. Therefore, as shown in FIG. 14B, if the driving range is the same, the correction angle increases when the focal length is short, and the focal length is When it is long, the correction angle becomes small. Therefore, the drive range and the correction angle are different, and the correction angle is not large because the drive range is large.

  In the known method, the correction drive amount is constant regardless of the focal length, and image blur correction is performed. Therefore, when the focal length is long, the correction angle becomes small, and the viewfinder observer has almost no anti-vibration effect. It feels like Alternatively, when the focal length is long, there is a sense of anxiety that the vibration isolator appears to be stopped at the position of the vibration isolation limit.

  In Patent Document 2, the correction means at the time of exposure has a higher shake correction characteristic than the correction means other than at the time of exposure. However, for a photographer who is actually looking through the viewfinder, the drive range of the correction device is limited. Therefore, there is a problem that the correction performance is deteriorated on the viewfinder.

  An object of the present invention is to solve the above-described problems, perform appropriate image blur correction even during exposure, and perform high-accuracy shooting, and does not give the photographer anxiety even while the photographer is observing the viewfinder. An imaging device is provided.

  Another object of the present invention is to provide an image pickup apparatus that secures a shake correction angle at which a shake correction effect can be sufficiently exhibited for each focal length and minimizes the shake correction angle range.

  In order to achieve the above object, the technical feature of the imaging apparatus according to the present invention includes a camera body and a lens barrel that is detachable from the camera body and includes a plurality of lens groups. In the image pickup apparatus in which the correction optical system is driven in a plane perpendicular to the optical axis, and image blur correction means for correcting image blur caused by camera shake is mounted, the image blur correction means has a blur correction characteristic of the first correction value. The correction optical system is driven during exposure to correct image shake on the imaging surface, and the correction optical system is driven and observed at times other than exposure based on the shake correction characteristic of the second correction value. The purpose is to correct image blur.

  A technical feature of the imaging apparatus according to the present invention is that a correction optical system for a part of the lens group in an imaging apparatus having a camera body and a lens barrel that is detachable from the camera body and includes a plurality of lens groups. And a correction angle for limiting the driving amount of the correction optical system so as to correct the vibration within a predetermined range of shake correction angle by controlling the correction driving unit. And a focal length detection unit that detects a focal length of the lens group. The correction angle limiting unit changes the shake correction angle before and during exposure, and the focal length information during the exposure. On the basis of the above, when the focal length is detected to be short, control is performed so that the range of the shake correction angle is increased compared to the case where the focal length is detected to be long.

  According to the imaging apparatus of the present invention, the degree of freedom of the optical system is increased by differentiating the shake correction of the image on the imaging surface driven at the time of exposure and the shake correction of the image driven at a time other than the exposure and observed by the photographer. Can be increased.

  The present invention will be described in detail based on the embodiment shown in FIGS.

  FIG. 1 shows a block circuit configuration diagram of an optical system and an electric system of a single-lens reflex camera according to the embodiment. The camera body 10 is an imaging device that constitutes an imaging system. An interchangeable lens 30 that is a lens device is detachably attached to the camera body 10, and the camera body 10 and the interchangeable lens 30 are electrically connected via an electrical contact 50. It is connected.

  In the camera body 10, on the optical path from the interchangeable lens 30, a quick return mirror 11 that can be moved up and down, a focal plane shutter 12 that controls the exposure amount, and an image sensor 13 such as a CCD sensor or a CMOS sensor that photoelectrically converts a subject image. Are arranged. A finder optical system 14 is provided in the reflection direction when the quick return mirror 11 is lowered. Further, a photometric unit (not shown) for measuring the amount of light from the interchangeable lens 30 is provided in the camera body 10, and a display device 15 is provided on the back of the camera body 10.

  The imaging signal output from the imaging device 13 is connected to a camera control microcomputer 16 that controls various operations of the camera body 10 and a focus detection circuit 17 that detects the focus state of the imaging optical system of the interchangeable lens 30. Further, the camera control microcomputer 16 is connected to the output of a main switch 18 provided on the exterior of the camera body 10, a shooting operation mode switch 19 for selecting a single shooting operation mode and a continuous shooting operation mode, and a release switch 20. ing. The release switch 20 includes first and second switches 20a and 20b having different strokes.

  The output of the camera control microcomputer 16 is connected to a camera communication microcomputer 21 that communicates with the interchangeable lens 30 via a communication contact among the shutter 12, the focus detection circuit 17, and the electrical contact 50. Further, the camera control microcomputer 16 is connected to a power supply circuit 22 that supplies power to each part in the camera body 10 and also supplies power to the interchangeable lens 30 via an electrical contact 50.

  The output of the image sensor 13 is input to an image processing circuit (not shown), where an image signal is generated based on the image signal. When the release switch 20 is pressed halfway and the first switch 20a is turned on, photometry, AF, and the like are performed and a shooting preparation state is set. When the release switch 20 is fully pressed and the second switch 20b is turned on, the shutter 12 opens and closes to capture an image, and an image signal is generated based on the output from the image sensor 13. The image signal is recorded on a recording medium such as a semiconductor memory or an optical disk in the camera control microcomputer 16 and displayed on the display device 15.

  The lens in the interchangeable lens 30 constitutes a photographic optical system, includes a variable power lens 31, a focusing lens, a diaphragm, and the like, and a correction lens 33 is provided as a vibration proof optical element that forms part of the vibration proof unit 32. ing. The correction lens 33 moves in a direction (pitch direction and yaw direction) orthogonal to the optical axis, thereby correcting image blur in the pitch direction and yaw direction of the subject image formed on the image sensor 13 of the camera body 10. Anti-vibration. The direction orthogonal to the optical axis includes not only the direction completely orthogonal to the optical axis but also the direction that can be considered optically orthogonal to the optical axis, the pitch direction is the vertical direction, and the yaw direction is It corresponds to the horizontal direction.

  The interchangeable lens 30 includes a lens control microcomputer 34, and the lens control microcomputer 34 is connected to an anti-vibration control microcomputer 35, a lens communication microcomputer 36 that communicates with the camera communication microcomputer 21 of the camera body 10, and a power supply determination circuit 37. Yes. The output of the image stabilization control microcomputer 35 is connected to an image stabilization actuator 38 that drives the correction lens 33. The image stabilization control microcomputer 35 includes a vibration sensor 39 and an image stabilization switch provided outside the lens barrel of the interchangeable lens 30. 40 is connected.

  The lens control microcomputer 34 performs drive control of the variable power lens 31, the focusing lens, and the aperture, and performs serial communication with the camera body 10 via the lens communication microcomputer 36. Further, the image stabilization control microcomputer 35 drives the correction lens 33 and controls the operation of the image stabilization actuator 38 constituted by a coil, a permanent magnet, and a yoke. The anti-vibration unit 32 includes a movable unit including an anti-vibration actuator 38 and a correction lens 33, a base member that holds the movable unit movably in the pitch direction and the yaw direction, and a member that guides the movement of the movable unit. Yes.

  The vibration sensor 39 is configured by an angular velocity sensor, an acceleration sensor, or the like, detects vibration by hand shake or the like of the entire imaging camera, and outputs an electrical signal corresponding to the vibration in the pitch direction and the yaw direction. The image stabilization control microcomputer 35 drives the correction lens 33 by the image stabilization actuator 38 based on the output signal from the vibration sensor 39.

  In addition, although not shown, the interchangeable lens 30 is provided with an aperture actuator, an aperture driver, a focus actuator, a focus driver, a focus position detector, a zoom operation ring, and a zoom position detector. The aperture driver drives the aperture actuator in accordance with a command from the lens control microcomputer 34 to operate the aperture. The focus driver drives the focus actuator in accordance with a command from the lens control microcomputer 34, and drives the focusing lens in the optical axis direction.

  When the zoom operation ring provided on the lens barrel is operated, the variable power lens 31 is driven in the optical axis direction by a variable power lens driving mechanism (not shown). The zoom position detector outputs a digital zoom position signal obtained by dividing a zoom range between the zoom position on the wide-angle side and the zoom position on the telephoto side into a predetermined number. The focus position detector outputs a digital focus position signal obtained by dividing a focus range between the closest focus position and the most infinite focus position into a predetermined number.

  These zoom and focus position signals are used to obtain focal length information and focus information necessary for performing AF calculation with high accuracy in the most commonly used TTL passive method as a single lens reflex (AF autofocus) method. used. Based on the position information, the lens control microcomputer 34 reads data necessary for the AF calculation from the table data stored in the internal ROM. The data is transmitted to the camera body 10 side, and the camera control microcomputer 16 that has read the data performs a predetermined AF calculation. Then, the camera control microcomputer 16 transmits a focus drive command obtained as a result of the AF calculation to the interchangeable lens 30 side. The lens control microcomputer 34 drives the focusing lens in response to the focus drive command.

  FIG. 2 is a front view of the image stabilization unit 32, and a support frame 62 is held on the base member 61, and the support frame 62 holds the correction lens 33. The support frame 62 is positioned by protrusions 61a and 61b provided on the base member 61, and a first yoke 63 made of a magnetic material is fixed to the base member 61 with screws or the like.

  FIG. 3 is a front view showing a state in which the first yoke 63 of FIG. 2 is removed. A winding coil 64 is fixed to the support frame 62, and a permanent magnet is magnetically attracted and fixed to the coil facing position of the first yoke 63. A second yoke, which is a magnetic body, is fixed on the base member 61 on the back side of the winding coil 64, and a closed magnetic path is formed between the first yoke 63 and the permanent magnet. The support frame 62 can be driven by energizing a winding coil 64 provided in the closed magnetic path and fixed to the support frame 62 to generate thrust.

  FIG. 4 is a front view in which the winding coil 64 and the second yoke are further removed from FIG. Radial holes 62a are provided at three positions about 120 degrees equally about the optical axis of the support frame 62. One end of the shift pin 65 is press-fitted into the hole 62a, and the other end of the shift pin 65 is the base member. 61 is inserted into a long hole 61 c provided in 61. Further, the long hole 61c extends in a plane direction orthogonal to the optical axis, whereby the support frame 62 is restricted from moving in the optical axis direction with respect to the base member 61, and can move in a plane orthogonal to the optical axis. .

  Compression springs 66 are interposed at three locations approximately equally at 120 degrees around the optical axis between the base member 61 and the support frame 62. The compression springs 66 elastically support the support frame 62 with respect to the base member 61. Yes. One of the compression springs 66 is positioned by a protrusion 62 b provided on the support frame 62, and the other is positioned by a protrusion 61 d provided on the base member 61.

  Since the protrusions 62b and 61d project radially from the optical axis and are provided so as to face each other on the same straight line, the compression spring 66 is also disposed radially from the optical axis. Further, when the winding coil 64 is not energized, the support frame 62 is held substantially at the center position of the optical axis by the compression spring 66.

  FIG. 5 is a flowchart of the operation sequence of the camera body 10 and the interchangeable lens 30. In the drawing, the flow surrounded by the dotted line frame on the left is the operation sequence of the camera body 10 by the camera control microcomputer 16, and the flow surrounded by the dotted line frame on the right is the interchangeable lens by the lens control microcomputer 34 and the image stabilization control microcomputer 35. 30 operation sequences. These operations are executed according to computer programs stored in the microcomputers 16, 34, and 35.

  The camera control microcomputer 16 detects the state of the first switch 20a of the release switch 20 in step S1. If it is off, this step S1 is repeated, and if it is on, it is preparation for photographing, so the process proceeds to step S2 to perform a photometric operation, and further proceeds to step S3 to perform a focal length detection operation. In step S3, the driving amount of the focusing lens is calculated and communicated to the lens control microcomputer 34, and then the process proceeds to step S4.

  The lens control microcomputer 34 drives the focusing lens in step S4 based on the focus drive amount information received from the camera control microcomputer 16, and proceeds to step S5. In step S5, the image stabilization control microcomputer 35 detects the state of the image stabilization switch 40. If it is on, the process proceeds to step S6, and if it is off, the process proceeds to step S8.

  Based on the focal length information received from the camera control microcomputer 16 via the lens control microcomputer 34, the image stabilization control microcomputer 35 is the second correction value of the image stabilization unit 32 before exposure, that is, at the time of composition determination in step S6. A correction angle driving amount is calculated. Then, it progresses to step S7, the image stabilization drive of the image stabilization unit 32 is started, and it progresses to step S8. The anti-vibration operation in this state is for the observer, and when the focal length is long, the correction angle is greatly driven.

  In step S8, the camera control microcomputer 16 performs the focus detection operation again to determine whether or not it is in focus. If it is in focus, the process proceeds to step S9. If it is not in focus, the process returns to step S1. In step S9, the state of the second switch 20b is detected, and if it is on, the process proceeds to step S10 to perform photographing. If it is off, the process returns to step S1.

  In step S10, a focus detection operation is performed, communication is performed with the lens control microcomputer 34, and then the process proceeds to step S11. Based on the focal length information received from the lens control microcomputer 34, the image stabilization control microcomputer 35 calculates a drive amount that is the first correction value of the image stabilization unit being exposed in step S11. Thereafter, the process proceeds to step S12, the image stabilization drive value of the image stabilization unit 32 is changed to the value calculated in step S11, and the process proceeds to step S13. In step S13, the camera control microcomputer 16 drives the shutter 12 to expose the image sensor 13, and in step S14, the imaging is completed.

  In the shake correction characteristic of the first correction value, the correction angle of the correction lens 33 is changed according to the focal length, so that image degradation due to shake is small when the focal length is short. Therefore, by reducing the driving range of the correction lens 33, image deterioration due to optical aberration can be prevented, and a highly accurate image can be acquired.

  The shake correction characteristic of the second correction value allows the photographer to observe a good correction state during viewfinder observation by increasing the correction angle of the correction lens 33 when the focal length is long.

  When the focal length is short, the correction angle can be reduced because the image stabilization sensitivity is high and image degradation due to shake is small. Therefore, in the present invention, when the image is acquired, by driving the correction lens 33 at an optimal correction angle according to the focal length so that an optimal image can be acquired during exposure, that is, during exposure, a highly accurate image can be obtained at the time of image acquisition. Can do.

  In this embodiment, at the time of composition determination when the photographer observes the viewfinder, the correction angle with the longer focal length is increased, that is, the correction lens 33 is driven to extend to the limit of the correction drive range as shown in FIG. I will do it. This eliminates anxiety when the photographer is observing the viewfinder.

  At this time, the image blur itself is corrected by the image stabilization unit 32. However, when the image is actually picked up by the movement of the correction lens 33, the image is deteriorated due to the optical aberration on the image plane. Therefore, in order to suppress image deterioration on the imaging plane, the driving amount of the correction lens 33 is reduced as much as possible during exposure.

  As described above, by making the shake correction characteristics of the first correction value and the second correction value different from each other, a highly accurate image can be taken.

  FIG. 7 is a cross-sectional view of the lens interchangeable digital single-lens reflex camera according to the second embodiment. An interchangeable lens 80 can be attached to the camera body 70. In the camera body 70, a quick return mirror 71, a sub mirror 72, and an image sensor 73 are arranged on the optical path from the interchangeable lens 80, and a focus detection unit 74 is provided in the reflection direction of the sub mirror 72. The focus detection unit 74 is a phase difference method including a condenser lens that divides an incident light beam into two light beams, two separator lenses that re-image the light beam, and a line sensor such as a CCD that photoelectrically converts the imaged subject image. AF sensor. A pentaprism 75 and a finder optical system 76 are provided in the reflection direction of the quick return mirror 71.

  On the other hand, in the interchangeable lens 80, a first lens group 81, a second lens group 82, a third lens group 83, a diaphragm 84, and a fourth lens group 85 are arranged along the optical axis. In the interchangeable lens 80, an AF drive motor 86 for driving the second lens group 82 is provided, and an anti-vibration actuator 87 is provided for driving the fourth lens group 85. Further, an angular shake detection sensor 88 composed of a vibration gyro or the like is provided.

  The second lens group 82 is a focusing optical system, moves on the optical axis in response to the driving force from the AF driving motor 86, and performs focus adjustment by stopping at a predetermined focusing position. The third lens group 83 is a variable magnification optical system, and its operating force is converted into driving in the optical axis direction by a transmission mechanism (not shown) that transmits the operation from the photographer, and in the optical axis direction so as to change the magnification. Driven.

  The fourth lens group 85 is a shake correction optical system. Based on the detection output from the angular shake detection sensor 88 such as a vibration gyro, the fourth lens group 85 is driven with respect to the optical axis by the drive force from the shake correction actuator 87 for shake correction drive. It moves in the vertical direction and bends the optical axis to correct angular shake.

  FIG. 8 is a front view of the fourth lens group 85 and the vibration isolation actuator 87. The lens barrel 91 supports a fourth lens group 85 that is a correction optical system, and the lens barrel 91 is supported by a base lens barrel 92. The lens barrel 91 engages with a cam 92a provided in the three directions formed on the base lens barrel 92, supports the fourth lens group 85 so as to be movable in a direction perpendicular to the optical axis, and prevents the optical axis direction from being tilted. It has the pin 91a to regulate.

  The X-direction drive coil 93 is integrally attached to the lens barrel 91, is energized from a control circuit via a flexible cable (not shown), and faces the permanent magnet (not shown) disposed in the base barrel 92 in the X direction. Thrust is generated. The Y-direction drive coil 94 is integrally attached to the lens barrel 91, energized from the control circuit via a flexible cable, and generates thrust in the Y-direction by facing the permanent magnet disposed in the base barrel 92. ing.

  An elastic member 95 made of a spring urges the lens barrel 91 from four directions. When the drive coil 94 is not energized, the elastic force of the elastic member 95 and the weight of the lens barrel 91 are suspended by the weight of the fourth lens group 85. The position is determined. On the other hand, when the drive coil 94 is energized, the thrust of the drive coil 94 and the weight of the barrel 91 are suspended from the elastic force of the elastic member 95, and the position of the fourth lens group 85 is determined.

  The sensor magnets 96a and 96b are integrally fixed to the lens barrel 91, face a hall element (not shown) attached to the base barrel 92, and move with the barrel 91 to detect the position of the fourth lens group 85. To do.

  FIG. 9 is a block circuit configuration diagram. The camera body 70 and the interchangeable lens 80 are electrically connected via the contact mechanism 100. A camera control microcomputer 111 in the camera body 70 is connected to a power switch 112 and a release switch 113 having first and second switches 113a and 113b having different strokes. Further, the camera control microcomputer 111 is connected with a photometry unit 114, a distance measurement unit 115, an exposure control unit 116, an imaging unit 117, a signal processing unit 118, and an image recording unit 119.

  On the other hand, the lens control microcomputer 121 in the interchangeable lens 80 has a correction drive control unit 122 and a maximum correction angle determination unit 123. The lens control microcomputer 121 is connected to an anti-vibration operation switch 124, a focusing drive unit 125, and an aperture drive unit 126. The correction drive control unit 122 is connected to an angular velocity detection unit 127, a correction optical system drive unit 128, and a position detection unit 129, and the maximum correction angle determination unit 123 is connected to a focal length detection unit 130.

  The camera control microcomputer 111 controls the operation of various devices in the camera body 70 and transmits and receives to / from the lens control microcomputer 121 via the contact mechanism 100 when the interchangeable lens 80 is mounted.

  The power switch 112 can be operated from the outside, and the camera control microcomputer 111 is activated so that power can be supplied to each actuator and sensor in the system and the system can be operated. If the first switch 113a of the release switch 113 is on, the camera control microcomputer 111 determines the exposure amount by the photometry unit 105 as a shooting preparation operation according to the signal input from the release switch 113. At the same time, the distance measuring unit 115 composed of an AF sensor measures the distance of the subject existing in the distance measuring area, determines the amount of movement of the second lens group 82 necessary for focusing, and focuses the lens in the interchangeable lens 80. The driving unit 125 is controlled to perform a focusing operation, and the photographing preparation state is entered.

  When the vibration-proof operation switch 124 of the interchangeable lens 80 is on, shake correction is started at the same time as shake detection. When it is detected that the second switch 113b of the release switch 113 has been operated to turn on to perform photographing, an operation command for the aperture driving unit 126 is transmitted to the camera control microcomputer 111. Then, an exposure start command is sent to the exposure control unit 116 including a shutter, the quick return mirror 71 is raised and the shutter is opened, and the subject image formed through the imaging optical system by the imaging unit 117 is photoelectrically converted. Then, a signal digitally converted by the signal processing unit 118 is output. The obtained image data is recorded and stored in a recording medium such as a semiconductor memory such as a flash memory, a magnetic disk, and an optical disk in an image recording unit 119.

  The image stabilization operation switch 124 can be operated from the outside, and can determine whether or not to perform the image blur correction operation. The angular velocity detection unit 127 includes a vibration gyro and the like, and includes a detection unit and a calculation output unit. The detection unit detects the angular velocity of the vertical shake (pitch direction) and the horizontal shake (yaw direction) according to the command from the lens control microcomputer 121, and the calculation output unit calculates a displacement obtained by integrating the output signal of the detection unit electrically or mechanically. Output to the lens control microcomputer 121.

  As shown in FIG. 8, the correction optical system drive unit 128 includes a fourth lens group 85, which is a correction optical system, suspended by an elastic member 95, and includes a drive unit that drives in the XY directions. Since the fourth lens group 85 is suspended by the elastic member 95, there is no locking means for locking the fourth lens group 85 when the image stabilization is off. The position detection unit 129 monitors the position of the fourth lens group 85.

  When the image stabilization operation switch 124 is turned on, the correction drive control unit 122 receives a correction angle for correcting the shake based on information from the angular velocity detection unit 127. This correction angle is converted according to the above-described anti-vibration sensitivity to obtain the correction amount of the fourth lens group 85, and the target displacement amount of the fourth lens group 85 is determined. When the image stabilization switch 124 is off, the fourth lens group 85 is not driven. Feedback control is performed based on the difference between the displacement of the fourth lens group 85 detected by the position detection unit 129 and the target displacement, and the fourth lens group 85 is driven so as to achieve the target displacement.

  Note that the maximum shake correction angle when the image stabilization operation switch 124 is turned on is determined by conditions. After the start of shake correction when the first switch 113a is turned on, a constant correction angle range based on the second correction value is set regardless of the focal length until exposure is started when the second switch 113b is turned on. Correction is performed. After the second switch 113b is turned on, during the exposure operation, shake correction is performed within a predetermined correction angle range based on the second correction value corresponding to the focal length based on a result of a maximum correction angle determination unit 123 described later. .

  The maximum correction angle determination unit 123 determines the maximum correction angle based on the result of a focal length detection unit described later. The focal length detection unit 130 outputs focal length information to the lens control microcomputer 121. The focusing drive unit 125 is configured to control the second lens group 82 by the lens control microcomputer 121 according to the movement amount of the second lens group 82 that is the focusing lens transmitted from the camera control microcomputer 111 as described above. ing. The diaphragm driving unit 126 that drives the diaphragm 84 determines the aperture area of the diaphragm 84 by the lens control microcomputer 121 according to the diaphragm operation command transmitted from the camera control microcomputer 111 as described above.

  FIG. 10 is a flowchart of the main operation of the second embodiment. First, in step S21, the power switch 112 of the camera body 70 is turned on, and supply of power to the interchangeable lens 80 is started. Alternatively, when a new battery is inserted or when the interchangeable lens 80 is attached to the camera body 70, communication is started between the camera body 70 and the interchangeable lens 80.

  Next, in step S22, the camera control microcomputer 111 determines whether or not the signal of the first switch 113a of the release switch 113 is generated. If it has occurred, the lens control microcomputer 121 determines in step S23 whether the image stabilization operation switch 124 is on, that is, whether the image stabilization operation has been determined. If the image stabilization operation has been determined, the process proceeds to step S24 to determine If not, the process proceeds to step S31.

  In step S24, vibration detection is started, and after a predetermined period of time during which the angular velocity detection unit 127 is stabilized, shake correction is started based on the vibration detection information for the observer. Note that the shake correction at this time is performed within a fixed correction angle range (± 0.15 degrees in the second embodiment) independent of the focal length. Next, in step S25, the current focal length is detected, and the focal length information is input to the lens control microcomputer 121. In step S26, the maximum shake correction angle during exposure is determined from the focal length information input in the lens control microcomputer 121. Specifically, a table is provided as the maximum shake correction angle for each focal length, and the maximum shake correction angle is selected from the input distance information.

  Here, in steps S25 and S26, recalculation is performed at a predetermined timing, and the determined maximum shake correction angle is updated according to the change in the focal length information until just before the start of exposure. In step S27, the camera control microcomputer 111 starts photometry and AF (ranging operation), and the lens control microcomputer 121 starts AF (focusing operation) and shake correction.

  In step S28, steps S22 to S28 are repeated until the second switch 113b is turned on by the full pressing operation of the release switch 113. When the second switch 113b is turned on, the process proceeds to step S29.

  In step S29, an exposure operation is started for imaging. Meanwhile, shake correction is performed within the range of the maximum shake correction angle determined in the process of step S26. The image exposed in step S30 is stored, and the process proceeds to step S22.

  If the image stabilization switch 124 is turned off in step S23, vibration detection and shake correction are not performed, and only AF and photometry are performed in step S31. Proceeding to step S32, the process waits by repeating step S22 to step S32 until the second switch 113b is turned on by a full-press operation. When the second switch 113b is turned on, the process proceeds to the exposure operation in step S33, and exposure is performed without camera shake correction.

  In this digital single-lens reflex camera, the above-described series of operations is repeated until the power switch 112 is turned off. When the power switch 112 is turned off, the communication between the camera control microcomputer 111 and the lens control microcomputer 121 ends, and the interchangeable lens 80 The power supply to is terminated.

  In general, the frequency of camera shake is 1 to 10 Hz and has an amplitude of 0.2 degrees at the maximum, and the amplitude becomes smaller as the frequency becomes higher. Therefore, in determining a necessary correction angle, a correction angle necessary for correcting camera shake with a frequency of 1 Hz and an amplitude of 0.2 degrees is considered.

  FIG. 11 shows the passage of time and the displacement of the angular shake when a sine wave shake of 1 Hz and an amplitude of 0.2 degrees occurs. The horizontal axis represents time (seconds), and the vertical axis represents the angular shake amount (degrees). Yes. In FIG. 11, for example, when the exposure time is 0.1 seconds, the maximum shake angle during that time is 0.06 degrees, and when the exposure time is 1 second, the maximum shake angle is 0.4 degrees.

  Table 1 shows the calculation of the maximum correction of the deflection angle for each focal length. Conventionally, the exposure time that is the limit of camera shake depends on the focal length, and 1 / f (focal length) has been the exposure time of the limit of camera shake. Here, on the premise that the camera shake effect is given to an exposure time that is three steps longer than the exposure time of 1 / f, the exposure time (seconds) that is longer by three steps with respect to the focal length (mm) and 1 / f. Table 1 shows the angular shake amount (degrees) generated during the exposure time.

Table 1
Focal length (mm) Exposure time (seconds) Angular deflection during exposure (degrees)
10 0.8 0.4
35 0.229 0.2632
50 0.160 0.1927
100 0.080 0.0995
200 0.040 0.0501
300 0.027 0.0335
400 0.020 0.0251
600 0.013 0.0168

  FIG. 12 is a graph showing the relationship between the focal length, the amount of angular shake occurring in the exposure time that is three steps longer than 1 / f, and the necessary correction angle. The horizontal axis is logarithmically expressed by the focal length, and the vertical axis indicates the amount of angular shake / necessary correction angle.

  As described above, the shake correction angle range before the start of exposure from when the first switch 113a of the release switch 113 is turned on to before the second switch 113b is turned on is set to a maximum of 0.15 degrees. For this reason, the correction angle required during exposure is set to a correction range by adding 0.15 degrees to the amount of angular shake that occurs in an exposure time that is three steps longer than 1 / f. With this configuration, the fourth lens group 85 is in the vicinity of the maximum correction angle limit before the start of exposure, and a sufficient shake correction angle can be secured even if shake correction during exposure is performed from that position.

  During exposure, a large correction angle is ensured on the wide-angle side. However, since the image stabilization sensitivity generally increases on the wide-angle side, the driving amount of the correction optical system itself does not become so large. Further, since the exposure time is shorter than the shake correction time before exposure, the influence on the power consumption is small.

  The above configuration ensures a sufficient correction angle even on the wide-angle side where the exposure time for which the shake correction effect is required is long, and limits the correction angle on the telephoto side where the shake correction effect can be obtained even with a short exposure time. This can save electricity. In addition, when observing with a finder before exposure, by setting a constant correction angle range regardless of the focal length, the correction angle is not unnecessarily widened on the wide-angle side, so that power saving can be achieved.

  The circuit configuration in the third embodiment is almost the same as that in FIG. 9 of the second embodiment, and the vibration isolation operation switch 124 not only switches on / off the vibration isolation operation, but also the normal vibration isolation operation mode 1 and power saving. The anti-vibration operation mode 2 can be selected.

  Therefore, the correction drive control unit 122 provides the operation mode 1 and the operation mode 2 with respect to the second embodiment, and when the operation mode 1 is selected, the correction range is set as described later when shifting from the pre-exposure state to the exposure state. Although it is changed, the shake correction is continued as it is. On the other hand, when the operation mode 2 is selected, the fourth lens group 85, which is a shake correction optical system, is once moved to the correction center immediately before exposure, and shake correction is performed with the start point of the fourth lens group 85 as the correction center at the start of exposure. Is called.

  When the operation mode 2 is selected, the shake correction range can be reduced by control. The shake correction operation is the same as that in the second embodiment, and the target displacement amount of the fourth lens group 85 is determined from the shake detection information from the angular velocity detection unit 127. Feedback control is performed from the difference between the displacement detected by the position detector 129 of the fourth lens group 85 and the target displacement, and the fourth lens group 85 is driven so as to achieve the target displacement.

  After the first switch 113a of the release switch 113 is turned on and after the shake correction is started, until the exposure is started by turning on the second switch 113b, a fixed correction angle range is set regardless of the selection of the operation modes 1 and 2 and the focal length. Is set. After the second switch 113b is turned on, shake correction is performed within a predetermined correction angle range corresponding to the focal length based on the result of the maximum correction angle determination unit 123 during the exposure operation. Here, when the operation mode 1 is selected, the shake correction angle is set larger than when the operation mode 2 is selected.

  Specifically, when the operation mode 1 is selected, as shown in FIG. 12, the correction range has an angle obtained by adding the maximum correction angle before exposure to the angular shake amount of the exposure time assumed according to the focal length. On the other hand, when the operation mode 2 is selected, the correction center is returned immediately before the exposure, so that only the amount of angular shake of the exposure time assumed according to the focal length is set as the correction range.

  FIG. 13 is a flowchart of the operation of the third embodiment. First, in step S41, the power switch 112 of the camera body 70 is turned on, and the supply of power to the interchangeable lens 80 is started.

  Next, in step S42, the camera control microcomputer 111 determines whether or not the first switch 113a is pressed. If it is pressed, the lens control microcomputer 121 determines in step S43 whether or not the image stabilization operation switch 124 has been turned on, and if it is determined that the image stabilization operation has been determined, the process must proceed to step S44. If so, the process proceeds to step S53.

  Vibration detection is started in step S44, and after a predetermined time when the angular velocity detection unit 127 is stabilized, shake correction is started based on the vibration detection information. Note that the shake correction at this time is performed within a certain correction angle range that does not depend on the focal length, for example, ± 0.15 degrees. In step S45, the current focal length is detected, and the focal length information is input to the lens control microcomputer 121.

  In step S46, the maximum shake correction angle during exposure is determined from the focal length information input in the lens control microcomputer 121. Specifically, a table is provided with the maximum shake correction angle as the second correction value for each focal length, and the maximum shake correction angle is selected from the input distance information. The maximum shake correction angle for each focal length has two series of correction angles for the operation mode 1 and correction angles for the operation mode 2, and the maximum shake correction angles of both are stored. Here, recalculation is performed at a predetermined timing in steps S45 and S46, and the determined maximum shake correction angle is updated according to the change in the focal length information until just before the start of exposure. In step S47, the camera control microcomputer 111 starts photometry and AF (ranging operation), and the lens control microcomputer 121 starts AF (focusing operation) and shake correction.

  In step S48, until the second switch 113b is turned on by the full pressing operation of the release switch 113, the process circulates in steps S42 to S48 and waits. When the second switch 113b is turned on, the process proceeds to step S49.

  In step S49, it is determined whether the image stabilization switch 124 has selected operation mode 1 or operation mode 2. When the operation mode 1 is selected, the correction angle for operation mode 1 stored in step S46 described above is being exposed. The correction range is set, and the process proceeds to step S51. On the other hand, when the operation mode 2 is selected, the correction range during exposure is set for the correction angle for the operation mode 2 stored in step S46 described above, and the process proceeds to step S50. In step S50, control is performed to return the fourth lens group 85 to the correction center. When the exposure operation is started in step S51, shake correction is performed within the range of the maximum shake correction angle determined for each of the operation mode 1 and operation mode 2 in step S46. The image exposed in step S52 is stored, and the process returns to step S42.

  If the image stabilization switch 124 is turned off in step S43, vibration detection and shake correction are not performed, and AF and photometry are performed in step S53. Proceeding to step S54, steps S42 to S54 are repeated until the second switch 113b is turned on. When the second switch 113b is turned on, the process proceeds to an exposure operation. In step S55, exposure is performed without correcting camera shake.

  In the third embodiment, the above-described series of operations is repeated until the power switch 112 is turned off. When the power switch 112 is turned off, communication between the camera control microcomputer 111 and the lens control microcomputer 121 ends, and the interchangeable lens 80 is connected to the interchangeable lens 80. Power supply ends.

  In the above description, preferred embodiments of the present invention have been described. However, it goes without saying that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the present invention.

1 is a block circuit configuration diagram of a single-lens reflex imaging camera of Embodiment 1. FIG. It is a front view of a vibration isolator unit. It is a front view of a vibration isolator unit. It is a front view of a vibration isolator unit. It is an operation | movement flowchart figure. It is operation | movement explanatory drawing of a correction lens. 6 is a cross-sectional view of a digital single-lens reflex camera according to Embodiment 2. FIG. It is a front view of an anti-vibration actuator. It is a block circuit block diagram. FIG. 6 is an operation flowchart of the second embodiment. It is a graph figure of passage of time and angular deflection displacement. It is a graph of the correction angle required for each focal length. FIG. 10 is an operation flowchart of the third embodiment. FIG. 10 is a relationship diagram between a driving range and a correction angle of a conventional image shake correction apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 70 Camera main body 13, 73 Image pick-up element 16, 111 Camera control microcomputer 20, 113 Release switch 30, 80 Interchangeable lens 32 Anti-vibration unit 33 Correction lens 34, 121 Lens control microcomputer 35 Anti-vibration control microcomputer 38, 87 Anti-vibration actuator 39 Vibration sensor 85 Fourth lens group (shake correction optical system)
88 Angular shake detection sensor 124 Anti-vibration operation switch

Claims (7)

  An image generated by camera shake, having a camera body and a lens barrel that is detachably attached to the camera body, and that drives a correction optical system of a part of the lens group in a plane perpendicular to the optical axis. In an image pickup apparatus equipped with an image shake correction unit that corrects a shake, the image shake correction unit drives the correction optical system during exposure based on the shake correction characteristic of the first correction value, and shakes the image on the imaging surface. And correcting the shake of the observed image by driving the correction optical system at a time other than the exposure based on the shake correction characteristic of the second correction value.   The imaging apparatus according to claim 1, wherein shake correction characteristics of the first correction value and the second correction value are different from each other.   The image pickup apparatus according to claim 1, wherein the image shake correction unit based on a shake correction characteristic of the first correction value changes a correction angle according to a focal length.   The image pickup apparatus according to claim 1, wherein the image shake correction unit based on a shake correction characteristic of the second correction value changes a correction angle greatly when a focal length is long.   In an imaging apparatus having a camera body and a lens barrel made of a plurality of lens groups, the correction drive unit driving a part of the correction optical system in the lens group within a plane orthogonal to the optical axis A correction angle limiting means for limiting the drive amount of the correction optical system so as to control the correction drive unit to correct within a predetermined range of shake correction angle, and a focus for detecting the focal length of the lens group A distance detecting unit, wherein the correction angle limiting unit changes the shake correction angle before and during exposure, and during the exposure, when the focal length is detected to be short based on the focal length information The image pickup apparatus controls the shake correction angle so that the range of the shake correction angle is increased when it is detected that the focal length is long.   The imaging apparatus according to claim 5, wherein the correction angle limiting unit controls the range of the shake correction angle to be constant before the exposure regardless of the focal length.   The imaging apparatus according to claim 5, wherein the correction driving unit drives the correction optical system suspended by an elastic member.

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