JP6610766B2 - Imaging device and interchangeable lens - Google Patents

Description

The present invention relates to an imaging device and an interchangeable lens.
As for the designated countries where incorporation by reference is permitted, the contents described in the application documents of Japanese Patent Application No. 2013-040116 filed in Japan on February 28, 2013 are incorporated into this application by reference. , Part of the description of this application.

  Conventionally, in order to suppress the driving sound of the focus lens, a technique for limiting the driving of the focus lens by setting an upper limit value for the driving speed of the focus lens is known (for example, see Patent Document 1).

JP 2007-6305 A

  The problem to be solved by the present invention is to provide an imaging device and an interchangeable lens that can suppress the driving sound of the focus lens.

  The present invention solves the above problems by the following means.

  An image pickup apparatus according to the present invention includes a first image plane movement coefficient determined corresponding to a position of the focus adjustment optical system, a second image plane movement coefficient independent of the position of the focus adjustment optical system, and the focus adjustment. Using a receiving unit that receives a silent speed determined according to the driving sound of the optical system, a determining unit that determines a search speed when searching for a focus evaluation value using contrast AF, and the first image plane movement coefficient Using the control unit that controls the focus adjustment optical system to drive at the search speed, the second image plane movement coefficient, and the silent speed, and the focus evaluation of the contrast AF at a speed different from the search speed. And a determination unit that determines whether or not to allow searching for a value.

  In the invention relating to the imaging apparatus, the search speed is a speed at which a moving speed of an image plane is constant, and the determination unit uses the second image plane moving coefficient and the silent speed to perform the focus adjustment optical. It is possible to permit the search of the focus evaluation value of the contrast AF at a moving speed of the image plane where the moving speed of the system is constant.

  In the invention relating to the imaging apparatus, the determination unit searches for the focus evaluation value of the contrast AF at a speed slower than the search speed using the second image plane movement coefficient and the silent speed. Can be configured to allow.

In the invention relating to the imaging apparatus, the determination unit may be configured such that a reference speed that is a moving speed of the image plane corresponding to the silent speed is V0, a coefficient of 1 or more is Kc, and the search speed is _Vlns. When V _lns × Kc> V0, it is possible to permit the search for the focus evaluation value of the contrast AF at a speed different from the search speed.

In the invention according to the imaging apparatus, the determination unit may be configured to search for the focus evaluation value of the contrast AF at a speed different from the search speed when V _lns × Kc ≦ V0.

  In the invention relating to the imaging apparatus, the determination unit may determine whether the image plane movement coefficient indicating the correspondence between the movement amount of the focus adjustment optical system and the movement amount of the image plane is the second image plane movement coefficient. The moving speed of the image plane when the focus adjusting optical system is driven at the silent speed can be configured to be the reference speed V0.

  In the invention according to the imaging apparatus, the determination unit is configured to increase the value of Kc as the aperture value is larger, the image compression rate is larger, or the pixel pitch of the imaging element is larger. Can do.

  In the invention relating to the imaging apparatus, the image plane movement coefficient is a coefficient indicating a correspondence relationship between the movement amount of the focus adjustment optical system and the movement amount of the image plane, and the focus adjustment optical system is faster than the silent speed. When driven at a speed, the focus adjustment optical system can be configured to have a lower drive sound than when driven at a speed slower than the silent speed.

In the invention relating to the imaging apparatus, the first image plane movement coefficient and the second image plane movement coefficient may be set to T _{L as} the movement amount in the optical axis direction of the focus adjustment optical system, and T _{I as} the movement amount of the image plane. and when a coefficient corresponding to the ratio between T _L and T _I, the second image plane shift factor, when a coefficient corresponding to T _I / T _L is the maximum T _I / T _L is It becomes a value, when the image plane shift factor is a coefficient corresponding to T _L / T _I may be T _L / T _I is configured such that a value becomes minimum.

  An interchangeable lens according to a first aspect of the present invention includes a drive unit that drives an optical system including a focus adjustment optical system, a first image plane movement coefficient that is determined according to a position of the focus adjustment optical system, A second image plane movement coefficient that does not depend on the position of the focus adjustment optical system, a transmission unit that transmits a silent speed determined corresponding to the driving sound of the focus adjustment optical system, and a search speed determined by the imaging device A lens control unit that controls the drive unit, and a reception unit that receives a signal that permits a search for a focus evaluation value of contrast AF at a speed different from the search speed, and the lens control unit includes: When the receiving unit receives the permission signal, the focus evaluation value of the contrast AF is searched at a speed different from the search speed.

  In the invention relating to the interchangeable lens, the lens control unit receives the signal permitted by the reception unit, and the search is performed when the speed of the focus adjustment optical system reaches a speed corresponding to the silent speed. The focus evaluation value of the contrast AF can be searched at a speed different from the speed.

  In the invention relating to the interchangeable lens, the lens control unit searches for a focus evaluation value of contrast AF so that a moving speed of the focus adjustment optical system is constant when the reception unit receives the signal permitted. Can be configured to do.

  An interchangeable lens according to a second aspect of the present invention includes: a receiving unit that receives a predetermined signal from a camera body; and the focus optics that receives the predetermined signal when the receiving unit does not receive the predetermined signal. And a control unit that controls the moving speed of the system to decrease.

  The interchangeable lens according to a third aspect of the present invention controls the focus optical system so that the focus optical system has a predetermined image plane movement speed when the movement speed of the focus optical system is faster than a predetermined speed. And a control unit that controls the focus optical system at a speed different from the predetermined image plane moving speed when the moving speed is slower than the predetermined speed.

  The invention relating to the interchangeable lens may include a receiving unit that receives a predetermined signal from the camera body.

  In the invention relating to the interchangeable lens, the predetermined signal may be configured to allow the focus optical system to move within a predetermined speed range.

  In the interchangeable lens according to the fourth aspect of the present invention, the transmission unit that transmits an image plane movement coefficient smaller than the image plane movement coefficient at the current position of the focus optical system, and the movement speed of the image plane are substantially constant. And a control unit that controls the focus optical system.

  An interchangeable lens according to a fifth aspect of the present invention includes a transmission unit that transmits an image plane movement coefficient smaller than the image plane movement coefficient at the current position of the focus optical system and information corresponding to the speed of the focus optical system. It is characterized by providing.

  In the invention relating to the interchangeable lens, the transmission unit includes an image plane movement coefficient at a current position of the focus optical system, an image plane movement coefficient smaller than an image plane movement coefficient at the current position of the focus optical system, and the focus. An image plane movement coefficient larger than the image plane movement coefficient at the current position of the optical system can be transmitted.

  The interchangeable lens according to the sixth aspect of the present invention transmits an image plane movement coefficient smaller than the image plane movement coefficient at the current position of the focus optical system and information corresponding to the movement speed of the focus optical system to the camera body. A transmission / reception unit that receives a predetermined signal from the camera body; and, when the predetermined signal is received, when the moving speed of the focus optical system is higher than a predetermined speed, the focus is set to a predetermined image plane moving speed. A control unit that performs drive control of the optical system, and performs drive control of the focus optical system so that the movement speed of the focus optical system is substantially constant when the movement speed of the focus optical system is slower than the predetermined speed; It is characterized by providing.

  In the invention relating to the interchangeable lens, when the control unit receives the predetermined signal and the moving speed of the focusing optical system is slower than the predetermined speed, the moving speed of the focusing optical system is the camera. The focus optical system can be controlled to be driven at a speed corresponding to the information transmitted to the body.

  In the invention relating to the interchangeable lens, the image plane movement coefficient smaller than the image plane movement coefficient at the current position of the focus optical system may be configured to be the minimum value of the image plane movement coefficient.

  In the invention relating to the interchangeable lens, an imaging optical system including the focus optical system can be provided.

  According to the present invention, the driving sound of the focus lens can be suppressed.

FIG. 1 is a perspective view showing a camera according to the present embodiment. FIG. 2 is a main part configuration diagram showing the camera according to the present embodiment. FIG. 3 is a table showing the relationship between the lens position (focal length) of the zoom lens, the lens position (shooting distance) of the focus lens, and the image plane movement coefficient K. FIG. 4 is a schematic diagram illustrating details of the connection units 202 and 302. FIG. 5 is a diagram illustrating an example of command data communication. FIG. 6 is a diagram illustrating an example of hotline communication. FIG. 7 is a flowchart showing the clip operation according to the present embodiment. FIG. 8 is a diagram for explaining the relationship between the lens driving speed V1b of the focus lens and the silent lower limit lens moving speed V0b. FIG. 9 is a flowchart showing clip operation control processing according to the present embodiment. FIG. 10 is a diagram for explaining the relationship between the image plane moving speed V1a of the focus lens and the silent lower limit image plane moving speed V0a_max. FIG. 11 is a diagram illustrating the relationship between the moving speed V1a of the image plane at the time of focus detection and the clipping operation. FIG. 12 is a diagram for explaining the relationship between the lens driving speed V1b of the focus lens and the clipping operation. FIG. 13 is a main part configuration diagram showing a camera according to another embodiment.

  FIG. 1 is a perspective view showing a single-lens reflex digital camera 1 of the present embodiment. Moreover, FIG. 2 is a principal part block diagram which shows the camera 1 of this embodiment. A digital camera 1 of the present embodiment (hereinafter simply referred to as a camera 1) includes a camera body 2 and a lens barrel 3, and the camera body 2 and the lens barrel 3 are detachably coupled.

  The lens barrel 3 is an interchangeable lens that can be attached to and detached from the camera body 2. As shown in FIG. 2, the lens barrel 3 includes a photographing optical system including lenses 31, 32, 33, 34 and a diaphragm 35.

  The lens 33 is a focus lens and can adjust the focal length of the photographing optical system by moving in the direction of the optical axis L1. The focus lens 33 is movably provided along the optical axis L 1 of the lens barrel 3, and its position is adjusted by the focus lens driving motor 331 while its position is detected by the focus lens encoder 332.

  The focus lens drive motor 331 is, for example, an ultrasonic motor, and drives the focus lens 33 in accordance with an electric signal (pulse) output from the lens control unit 36. Specifically, the drive speed of the focus lens 33 by the focus lens drive motor 331 is expressed in pulses / second, and the drive speed of the focus lens 33 increases as the number of pulses per unit time increases. In this embodiment, the camera control unit 21 of the camera body 2 transmits the drive instruction speed (unit: pulses / second) of the focus lens 33 to the lens barrel 3, and the lens control unit 36 is transmitted from the camera body 2. By outputting a pulse signal corresponding to the transmitted drive instruction speed (unit: pulses / second) to the focus lens drive motor 331, the drive instruction speed (unit: pulse) transmitted from the camera body 2 to the focus lens 33 is output. / Second).

  The lens 32 is a zoom lens, and can move in the optical axis L1 direction to adjust the shooting magnification of the shooting optical system. Similarly to the focus lens 33 described above, the position of the zoom lens 32 is adjusted by the zoom lens driving motor 321 while the position thereof is detected by the zoom lens encoder 322. The position of the zoom lens 32 is adjusted by operating a zoom button provided on the operation unit 28 or operating a zoom ring (not shown) provided on the camera barrel 3.

  The diaphragm 35 is configured such that the aperture diameter around the optical axis L1 can be adjusted in order to limit the amount of light flux that passes through the photographing optical system and reaches the image sensor 22 and adjust the amount of blur. The adjustment of the aperture diameter by the diaphragm 35 is performed, for example, by sending an appropriate aperture diameter calculated in the automatic exposure mode from the camera control unit 21 via the lens control unit 35. Further, the set aperture diameter is input from the camera control unit 21 to the lens control unit 36 by a manual operation by the operation unit 28 provided in the camera body 2. The aperture diameter of the aperture 35 is detected by an aperture sensor (not shown), and the lens controller 36 recognizes the current aperture diameter.

The lens memory 37 stores an image plane movement coefficient K. The image plane movement coefficient K is a value indicating a correspondence relationship between the driving amount of the focus lens 33 and the moving amount of the image plane, and is, for example, a ratio between the driving amount of the focus lens 33 and the moving amount of the image plane. In this embodiment, the image plane movement coefficient is obtained by the following equation (3), for example. As the image plane movement coefficient K decreases, the amount of movement of the image plane accompanying the driving of the focus lens 33 increases.
Image plane movement coefficient K = (drive amount of focus lens 33 / movement amount of image plane) (3)
Further, in the camera 1 of the present embodiment, even when the driving amount of the focus lens 33 is the same, the moving amount of the image plane varies depending on the lens position of the focus lens 33. Similarly, even when the drive amount of the focus lens 33 is the same, the movement amount of the image plane varies depending on the lens position of the zoom lens 32. That is, the image plane movement coefficient K changes in accordance with the lens position in the optical axis direction of the focus lens 33 and further in accordance with the lens position in the optical axis direction of the zoom lens 32. In this embodiment, the lens control unit 36 stores an image plane movement coefficient K for each lens position of the focus lens 33 and each lens position of the zoom lens 32.
The image plane movement coefficient K can also be defined as, for example, an image plane movement coefficient K = (image plane movement amount / focus lens 33 drive amount). In this case, as the image plane movement coefficient K increases, the amount of movement of the image plane accompanying the driving of the focus lens 33 increases.

  FIG. 3 shows a table showing the relationship between the lens position (focal length) of the zoom lens 32 and the lens position (shooting distance) of the focus lens 33 and the image plane movement coefficient K. In the table shown in FIG. 3, the drive region of the zoom lens 32 is divided into nine regions “f1” to “f9” in order from the wide end to the tele end, and the drive region of the focus lens 33 is closest. In order from the end toward the end at infinity, the image plane movement coefficient K corresponding to each lens position is stored in nine areas “D1” to “D9”. For example, when the lens position (focal length) of the zoom lens 32 is “f1” and the lens position (shooting distance) of the focus lens 33 is “D1”, the image plane movement coefficient K is “K11”. The table shown in FIG. 3 exemplifies a mode in which the driving area of each lens is divided into nine areas, but the number is not particularly limited and can be arbitrarily set.

Next, the minimum image plane movement coefficient K _min and the maximum image plane movement coefficient K _max will be described with reference to FIG.
The minimum image plane movement coefficient K _min is a value corresponding to the minimum value of the image plane movement coefficient K. The minimum image plane movement coefficient K _min is preferably changed according to the current lens position of the zoom lens 32. Further, the minimum image plane movement coefficient K _min is preferably a constant value (fixed value) even if the current lens position of the focus lens 33 changes unless the current lens position of the zoom lens 32 changes. That is, the minimum image plane movement coefficient K _min is a fixed value (constant value) determined according to the lens position (focal length) of the zoom lens 32 and is not dependent on the lens position (shooting distance) of the focus lens 33. It is preferable that

For example, in FIG. 3, “K11”, “K21”, “K31”, “K41”, “K52”, “K62”, “K72”, “K82”, and “K91” shown in gray are the zoom lens 32. The minimum image plane movement coefficient K _min indicating a minimum value among the image plane movement coefficients K at the respective lens positions (focal lengths). That is, when the lens position (focal length) of the zoom lens 32 is “f1”, the lens position (shooting distance) of the focus lens 33 among “D1” to “D9” is “D1”. “K11” which is the image plane movement coefficient K is the minimum image plane movement coefficient K _min indicating the minimum value. Accordingly, “K11”, which is the image plane movement coefficient K when the lens position (shooting distance) of the focus lens 33 is “D1”, has a lens position (shooting distance) of the focus lens 33 of “D1” to “D9”. Is the smallest value among the image plane movement coefficients K “K11” to “K19”. Similarly, even when each lens position (focal length) of the zoom lens 32 is “f2”, the image plane movement coefficient K is obtained when the lens position (shooting distance) of the focus lens 33 is “D1”. “K21” indicates the smallest value among “K21” to “K29” that are the image plane movement coefficients K when “K1” is “D1” to “D9”. That is, “K21” is the minimum image plane movement coefficient K _min . Similarly, even when each lens position (focal length) of the zoom lens 32 is “f3” to “f9”, “K31”, “K41”, “K52”, “K62”, “K” shown in gray “K72”, “K82”, and “K91” are the minimum image plane movement coefficient K _min .

Similarly, the maximum image plane movement coefficient K _max is a value corresponding to the maximum value of the image plane movement coefficient K. The maximum image plane movement coefficient K _max is preferably changed according to the current lens position of the zoom lens 32. The maximum image plane movement coefficient K _max is preferably a constant value (fixed value) even if the current lens position of the focus lens 33 changes unless the current lens position of the zoom lens 32 changes. For example, in FIG. 3, “K19”, “K29”, “K39”, “K49”, “K59”, “K69”, “K79”, “K89”, “K99” shown by hatching are zoomed. This is the maximum image plane movement coefficient K _max indicating the maximum value among the image plane movement coefficients K at each lens position (focal length) of the lens 32.

Thus, as shown in FIG. 3, the lens memory 37 includes an image plane movement coefficient K corresponding to the lens position (focal length) of the zoom lens 32 and the lens position (shooting distance) of the focus lens 33, and the zoom lens. For each of the 32 lens positions (focal length), the minimum image plane movement coefficient K _min indicating the minimum value of the image plane movement coefficient K, and for each lens position (focal length) of the zoom lens 32, the image plane movement coefficient. A maximum image plane movement coefficient K _max indicating the maximum value of K is stored.

  The lens memory 37 stores a silent lower limit lens moving speed V0b. For example, when the focus lens 33 is driven at a low speed below a certain speed, the driving load of the focus lens drive motor 331 increases, and a drive sound of a predetermined value or more (for example, a drive sound of 50 decibels or more) is generated. There is a case. The silent lower limit lens moving speed V0b is such that when the focus lens 33 is driven at a speed equal to or higher than the silent lower limit lens moving speed V0b, such a driving sound exceeding the predetermined value can be prevented. It is a moving speed.

  On the other hand, the camera body 2 includes a mirror system 220 for guiding the light flux from the subject to the image sensor 22, the finder 235, the photometric sensor 237, and the focus detection module 261. The mirror system 220 includes a quick return mirror 221 that rotates about a rotation axis 223 by a predetermined angle between the observation position and the imaging position of the subject, and the quick return mirror 221 that is pivotally supported by the quick return mirror 221. And a sub mirror 222 that rotates in accordance with the rotation. In FIG. 1, a state where the mirror system 220 is at the observation position of the subject is indicated by a solid line, and a state where the mirror system 220 is at the imaging position of the subject is indicated by a two-dot chain line.

  The mirror system 220 is inserted on the optical path of the optical axis L1 in a state where the subject is at the observation position of the subject, while rotating so as to be retracted from the optical path of the optical axis L1 in a state where the mirror system 220 is at the imaging position of the subject.

  The quick return mirror 221 is composed of a half mirror, and in a state where the subject is at the observation position of the subject, the quick return mirror 221 reflects a part of the luminous flux (optical axis L1, L3) of the luminous flux (optical axis L1) from the subject. Then, the light is guided to the finder 235 and the photometric sensor 237, and a part of the light beam (optical axis L4) is transmitted to the sub mirror 222. On the other hand, the sub mirror 222 is constituted by a total reflection mirror, and guides the light beam (optical axis L4) transmitted through the quick return mirror 221 to the focus detection module 261.

  Therefore, when the mirror system 220 is at the observation position, the light beam (optical axis L1) from the subject is guided to the finder 235, the photometric sensor 237, and the focus detection module 261, and the subject is observed by the photographer and exposure calculation is performed. And the focus adjustment state of the focus lens 33 is detected. Then, when the photographer fully presses the release button, the mirror system 220 rotates to the photographing position, and all the luminous flux (optical axis L1) from the subject is guided to the image sensor 22, and the photographed image data is stored in the memory 24. .

  The light beam (optical axis L2) from the subject reflected by the quick return mirror 221 forms an image on a focusing screen 231 disposed on a surface optically equivalent to the imaging element 22, and the pentaprism 233 and the eyepiece 234 are formed. It is possible to observe through. At this time, the transmissive liquid crystal display 232 superimposes and displays a focus detection area mark on the subject image on the focusing screen 231, and also relates to shooting such as the shutter speed, aperture value, and number of shots in an area outside the subject image. Display information. As a result, the photographer can observe the subject, its background, and photographing related information through the finder 235 in the photographing preparation state.

  The photometric sensor 237 is composed of a two-dimensional color CCD image sensor or the like, and divides the photographing screen into a plurality of regions and outputs a photometric signal corresponding to the luminance of each region in order to calculate an exposure value at the time of photographing. The signal detected by the photometric sensor 237 is output to the camera control unit 21 and used for automatic exposure control.

  The imaging element 22 is provided on the planned focal plane of the photographing optical system including the lenses 31, 32, 33, and 34 on the optical axis L1 of the light beam from the subject of the camera body 2, and a shutter 23 is provided on the front surface thereof. Is provided. The image pickup element 22 has a plurality of photoelectric conversion elements arranged two-dimensionally, and can be constituted by a device such as a two-dimensional CCD image sensor, a MOS sensor, or a CID. The image signal photoelectrically converted by the image sensor 22 is subjected to image processing by the camera control unit 21 and then recorded in a camera memory 24 which is a recording medium. The camera memory 24 can be either a removable card type memory or a built-in memory.

  In addition, the camera control unit 21 detects the focus adjustment state of the photographing optical system using a contrast detection method based on the pixel data read from the image sensor 22. For example, the camera control unit 21 reads the output of the image sensor 22 and calculates a focus evaluation value based on the read output. This focus evaluation value can be obtained, for example, by extracting a high-frequency component of the output from the image sensor 22 using a high-frequency transmission filter. It can also be obtained by extracting high-frequency components using two high-frequency transmission filters having different cutoff frequencies.

  Then, the camera control unit 21 sends a drive signal to the lens control unit 36 to drive the focus lens 33 at a predetermined sampling interval (distance), obtains a focus evaluation value at each position, and the focus evaluation value is maximum. The focus detection by the contrast detection method is performed in which the position of the focus lens 33 is determined as the in-focus position. Note that this in-focus position is obtained when, for example, the focus evaluation value is calculated while the focus lens 33 is driven, and the focus evaluation value rises twice and then moves down twice. Can be obtained by performing an operation such as interpolation using the focus evaluation value.

  In focus detection by the contrast detection method, the sampling interval of the focus evaluation value increases as the driving speed of the focus lens 33 increases, and when the driving speed of the focus lens 33 exceeds a predetermined speed, the sampling interval of the focus evaluation value Becomes too large, and the in-focus position cannot be detected properly. This is because, as the focus evaluation value sampling interval increases, the object to be detected can detect the focus state properly even once when the focus lens 33 is driven from the closest end to the infinity end. This is because the focus state at the position of the subject cannot be properly detected without entering the depth. Therefore, the camera control unit 21 drives the focus lens 33 so that the moving speed of the image plane when the focus lens 33 is driven becomes a speed at which the in-focus position can be appropriately detected. For example, in the search control for driving the focus lens 33 to detect the focus evaluation value, the camera control unit 21 can detect the in-focus position appropriately, and the maximum image plane among the image plane moving speeds at the sampling interval. The focus lens 33 is driven so as to achieve the driving speed. The search control includes, for example, wafer ring, neighborhood search (neighbor scan) for searching only the vicinity of a predetermined position, and global search (global scan) for searching the entire drive range of the focus lens 33.

  The camera control unit 21 drives the focus lens 33 at a high speed when starting the search control using a half-press of the release switch as a trigger, and starts the search control using a condition other than the half-press of the release switch as a trigger. Alternatively, the focus lens 33 may be driven at a low speed. By controlling in this way, contrast AF can be performed at a high speed when the release switch is half-pressed, and contrast AF can be performed when the release switch is not half-pressed, and the appearance of the through image is favorable. It is.

  Further, the camera control unit 21 may perform control so that the focus lens 33 is driven at high speed in search control in the still image shooting mode, and the focus lens 33 is driven at low speed in search control in the moving image shooting mode. By controlling in this way, contrast AF can be performed at high speed in the still image shooting mode, and contrast AF suitable for the appearance of the moving image can be performed in the moving image shooting mode.

  In at least one of the still image shooting mode and the moving image shooting mode, the contrast AF may be performed at high speed in the sport shooting mode, and the contrast AF may be performed at low speed in the landscape shooting mode. Further, the driving speed of the focus lens 33 in the search control may be changed according to the focal length, the shooting distance, the aperture value, and the like.

  Furthermore, in the present embodiment, focus detection by a phase difference detection method can also be performed. Specifically, the focus detection module 261 includes a pair of pixels each including a plurality of pixels each having a microlens disposed in the vicinity of a predetermined focal plane of the imaging optical system and photoelectric conversion elements disposed with respect to the microlens. Line sensor (not shown). A pair of image signals can be acquired by receiving a pair of light fluxes passing through a pair of regions having different exit pupils of the focus lens 33 at each pixel arranged in a pair of line sensors. Then, it is possible to perform focus detection by a phase difference detection method for detecting a focus adjustment state by obtaining a phase shift between a pair of image signals acquired by a pair of line sensors by a well-known correlation calculation described later.

  The operation unit 28 is an input switch for a photographer to set various operation modes of the camera 1, such as a shutter release button and a moving image shooting start switch, and switches between a still image shooting mode / moving image shooting mode, an autofocus mode / manual. The focus mode can be switched, and the AF-S mode / AF-F mode can be switched even in the auto focus mode. Various modes set by the operation unit 28 are sent to the camera control unit 21, and the operation of the entire camera 1 is controlled by the camera control unit 21. The shutter release button includes a first switch SW1 that is turned on when the button is half-pressed and a second switch SW2 that is turned on when the button is fully pressed.

  Here, the AF-S mode is to fix the position of the focus lens 33 once adjusted after the focus lens 33 is driven based on the focus detection result when the shutter release button is half-pressed. In this mode, shooting is performed at the focus lens position. The AF-S mode is a mode suitable for still image shooting, and is normally selected when still image shooting is performed. In the AF-F mode, the focus lens 33 is driven based on the focus detection result regardless of whether or not the shutter release button is operated, and then the focus state is repeatedly detected. In this mode, the focus lens 33 is scanned. The AF-F mode is a mode suitable for moving image shooting, and is usually selected when moving image shooting is performed.

  In the present embodiment, a switch for switching the one-shot mode / continuous mode may be provided as a switch for switching the autofocus mode. In this case, when the one-shot mode is selected by the photographer, the AF-S mode is set, and when the continuous mode is selected by the photographer, the AF-F mode is set. It can be set as such.

  Next, a data communication method between the camera body 2 and the lens barrel 3 will be described.

  The camera body 2 is provided with a body side mount portion 201 to which the lens barrel 3 is detachably attached. Further, as shown in FIG. 1, a connection portion 202 that protrudes to the inner peripheral side of the body side mount portion 201 is provided in the vicinity of the body side mount portion 201 (inner peripheral side of the body side mount portion 201). ing. The connection portion 202 is provided with a plurality of electrical contacts.

  On the other hand, the lens barrel 3 is provided with an interchangeable lens that can be attached to and detached from the camera body 2, and a lens-side mount portion 301 that is detachably attached to the camera body 2. Further, as shown in FIG. 1, a connecting portion 302 that protrudes to the inner peripheral side of the lens side mount portion 301 is provided in the vicinity of the lens side mount portion 301 (inner peripheral side of the lens side mount portion 301). ing. The connecting portion 302 is provided with a plurality of electrical contacts.

  When the lens barrel 3 is attached to the camera body 2, the electrical contact of the connection portion 202 provided on the body side mount portion 201 and the electrical contact of the connection portion 302 provided on the lens side mount portion 301 are electrically connected. Connected physically and physically. Thereby, power supply from the camera body 2 to the lens barrel 3 and data communication between the camera body 2 and the lens barrel 3 can be performed via the connection units 202 and 302.

  FIG. 4 is a schematic diagram showing details of the connecting sections 202 and 302. In FIG. 4, the connection portion 202 is arranged on the right side of the body-side mount portion 201 in accordance with the actual mount structure. In other words, the connection portion 202 of this embodiment is disposed at a location deeper than the mounting surface of the body side mount portion 201 (a location on the right side of the body side mount portion 201 in FIG. 4). Similarly, the connection portion 302 is disposed on the right side of the lens side mount portion 301 because the connection portion 302 of the present embodiment is disposed at a position protruding from the mount surface of the lens side mount portion 301. Represents. By arranging the connection portion 202 and the connection portion 302 in this way, the mount surface of the body-side mount portion 201 and the mount surface of the lens-side mount portion 301 are brought into contact with each other, so that the camera body 2 and the lens barrel 3 Are connected to each other, the connecting portion 202 and the connecting portion 302 are connected to each other, and the electrical contacts provided in both the connecting portions 202 and 302 are connected to each other.

  As shown in FIG. 4, twelve electrical contacts BP <b> 1 to BP <b> 12 exist in the connection portion 202. Further, twelve electrical contacts LP1 to LP12 corresponding to the twelve electrical contacts on the camera body 2 side exist in the connection portion 302 on the lens 3 side.

  The electrical contacts BP1 and BP2 are connected to the first power supply circuit 230 in the camera body 2. The first power supply circuit 230 supplies an operating voltage to each part in the lens barrel 3 (excluding circuits having relatively large power consumption such as the lens driving motors 321 and 331) via the electrical contact BP1 and the electrical contact LP1. Supply. The voltage value supplied by the first power supply circuit 230 via the electrical contact BP1 and the electrical contact LP1 is not particularly limited, and is, for example, a voltage value of 3 to 4 V (typically 3 in the middle of this voltage width). Voltage value in the vicinity of 0.5 V). In this case, the current value supplied from the camera body side 2 to the lens barrel side 3 is a current value within a range of about several tens mA to several hundred mA in the power-on state. Further, the electrical contact BP2 and the electrical contact LP2 are ground terminals corresponding to the operation voltage supplied via the electrical contact BP1 and the electrical contact LP1.

  The electrical contacts BP3 to BP6 are connected to the camera side first communication unit 291. Corresponding to these electrical contacts BP3 to BP6, the electrical contacts LP3 to LP6 are connected to the lens side first communication unit 381. . The camera-side first communication unit 291 and the lens-side first communication unit 381 transmit and receive signals to and from each other using these electrical contacts. The contents of communication performed by the camera-side first communication unit 291 and the lens-side first communication unit 381 will be described in detail later.

  The electrical contacts BP7 to BP10 are connected to the camera-side second communication unit 292, and the electrical contacts LP7 to LP10 are connected to the lens-side second communication unit 382 corresponding to the electrical contacts BP7 to BP10. . And the camera side 2nd communication part 292 and the lens side 2nd communication part 382 mutually transmit / receive a signal using these electrical contacts. The contents of communication performed by the camera side second communication unit 292 and the lens side second communication unit 382 will be described in detail later.

  The electrical contacts BP11 and BP12 are connected to a second power supply circuit 240 in the camera body 2. The second power supply circuit 240 supplies an operating voltage to circuits with relatively large power consumption, such as the lens drive motors 321 and 331, via the electrical contact BP11 and the electrical contact LP11. The voltage value supplied by the second power supply circuit 230 is not particularly limited, but the maximum voltage value supplied by the second power supply circuit 240 is the number of maximum voltage values supplied by the first power supply circuit 230. It can be about double. In this case, the current value supplied from the second power supply circuit 240 to the lens barrel 3 side is a current value within a range of about several tens of mA to several A in the power-on state. The electrical contact BP12 and the electrical contact LP12 are ground terminals corresponding to the operating voltage supplied through the electrical contact BP11 and the electrical contact LP11.

  The first communication unit 291 and the second communication unit 292 on the camera body 2 side shown in FIG. 4 constitute the camera transmission / reception unit 29 shown in FIG. 1, and the first communication unit on the lens barrel 3 side shown in FIG. 381 and the second communication unit 382 constitute the lens transmission / reception unit 38 shown in FIG.

  Next, communication between the camera-side first communication unit 291 and the lens-side first communication unit 381 (hereinafter referred to as command data communication) will be described. The lens control unit 36 includes a signal line CLK composed of electrical contacts BP3 and LP3, a signal line BDAT composed of electrical contacts BP4 and LP4, a signal line LDAT composed of electrical contacts BP5 and LP5, and electrical contacts Transmission of control data from the camera-side first communication unit 291 to the lens-side first communication unit 381 via the signal line RDY composed of BP6 and LP6, and the lens-side first communication unit 381 to the camera-side first Command data communication is performed in parallel with transmission of response data to the communication unit 291 at a predetermined cycle (for example, at intervals of 16 milliseconds).

  FIG. 5 is a timing chart showing an example of command data communication. The camera control unit 21 and the first camera-side communication unit 291 first confirm the signal level of the signal line RDY at the start of command data communication (T1). Here, the signal level of the signal line RDY indicates whether or not the lens-side first communication unit 381 can communicate. When communication is not possible, the lens control unit 36 and the lens-side first communication unit 381 perform H (High). A level signal is output. The first camera-side communication unit 291 does not perform communication with the lens barrel 3 when the signal line RDY is at the H level, or does not execute the next process even during communication.

  On the other hand, when the signal line RDY is at the L (LOW) level, the camera control unit 21 and the camera-side first communication unit 291 transmit the clock signal 401 to the lens-side first communication unit 291 using the signal line CLK. . Further, the camera control unit 21 and the camera side first communication unit 291 use the signal line BDAT in synchronization with the clock signal 401 to transmit the camera side command packet signal 402 as control data to the lens side first communication unit 291. Send to. When the clock signal 401 is output, the lens control unit 36 and the lens-side first communication unit 381 synchronize with the clock signal 401 and use the signal line LDAT to send a lens-side command packet signal that is response data. 403 is transmitted.

  The lens control unit 36 and the lens side first communication unit 291 change the signal level of the signal line RDY from the L level to the H level in response to the completion of the transmission of the lens side command packet signal 403 (T2). Then, the lens control unit 36 starts the first control process 404 according to the content of the body side command packet signal 402 received up to time T2.

  For example, when the received body-side command packet signal 402 is content requesting specific data on the lens barrel 3 side, the lens control unit 36 uses the content of the command packet signal 402 as the first control processing 404. Along with the analysis, a process for generating the requested specific data is executed. Further, as the first control process 404, the lens control unit 36 uses the checksum data included in the command packet signal 402 to simplify whether there is no error in the communication of the command packet signal 402 from the number of data bytes. A communication error check process is also executed. The specific data signal generated in the first control process 404 is output to the camera body 2 side as a lens-side data packet signal 407 (T3). In this case, the camera-side data packet signal 406 output from the camera body 2 side after the command packet signal 402 is dummy data (including checksum data) that has no particular meaning for the lens side. . In this case, the lens control unit 36 executes the communication error check process as described above using the checksum data included in the camera-side data packet signal 406 as the second control process 408 (T4).

  For example, when the camera-side command packet signal 402 is an instruction to drive the focus lens 33 and the camera-side data packet signal 406 is the drive speed and drive amount of the focus lens 33, the lens control unit 36 As the control process 404, the contents of the command packet signal 402 are analyzed, and a confirmation signal indicating that the contents have been understood is generated (T2). The confirmation signal generated in the first control process 404 is output to the camera body 2 as a lens-side data packet signal 407 (T3). In addition, as the second control process 408, the lens control unit 36 analyzes the contents of the camera-side data packet signal 406 and executes a communication error check process using the checksum data included in the camera-side data packet signal 406. (T4). After the completion of the second control processing 408, the lens control unit 36 drives the focus lens drive motor 331 based on the received camera side command packet signal 406, that is, the drive speed and drive amount of the focus lens 33. Thus, the focus lens 33 is driven at the received drive speed by the received drive amount (T5).

  In addition, when the second control process 408 is completed, the lens control unit 36 notifies the lens-side first communication unit 291 that the second control process 408 is completed. Thereby, the lens controller 36 outputs an L level signal to the signal line RDY (T5).

  The communication performed between the times T1 to T5 described above is one command data communication. As described above, in one command data communication, the camera-side command packet signal 402 and the camera-side data packet signal 406 are transmitted one by one by the camera control unit 21 and the camera-side first communication unit 291, respectively. As described above, in this embodiment, the control data transmitted from the camera body 2 to the lens barrel 3 is divided into two for convenience of processing, but the camera side command packet signal 402 and the camera side are transmitted. Two data packet signals 406 constitute one control data.

  Similarly, in one command data communication, the lens control unit 36 and the lens side first communication unit 381 transmit one lens side command packet signal 403 and one lens side data packet signal 407, respectively. As described above, the response data transmitted from the lens barrel 3 to the camera body 2 is also divided into two, but one response data includes both the lens side command packet signal 403 and the lens side data packet signal 407. Configure.

  Next, communication between the camera-side second communication unit 292 and the lens-side second communication unit 382 (hereinafter referred to as hotline communication) will be described. The lens control unit 36 includes a signal line HREQ composed of electrical contacts BP7 and LP7, a signal line HANS composed of electrical contacts BP8 and LP8, a signal line HCLK composed of electrical contacts BP9 and LP9, and electrical contacts BP10 and LP10. Hot line communication for performing communication at a cycle shorter than command data communication (for example, at an interval of 1 millisecond) is performed via a signal line HDAT composed of

For example, in the present embodiment, lens information of the lens barrel 3 is transmitted from the lens barrel 3 to the camera body 2 by hotline communication. The lens information transmitted by hot line communication includes the lens position of the focus lens 33, the lens position of the zoom lens 32, the current position image plane movement coefficient K _cur , the minimum image plane movement coefficient K _min , and the maximum image plane movement coefficient. K _max and the silent lower limit lens moving speed V0b are included. Here, the current position image plane movement coefficient K _cur is an image plane movement coefficient K corresponding to the current zoom lens position (focal distance) and the current focus lens position (shooting distance). In the present embodiment, the lens control unit 36 refers to a table stored in the lens memory 37 and indicating the relationship between the lens position (zoom lens position and focus lens position) and the image plane movement coefficient K, so that the zoom lens The current position image plane movement coefficient K _cur corresponding to the current lens position of 32 and the current lens position of the focus lens 33 can be obtained. For example, in the example shown in FIG. 3, when the lens position (focal distance) of the zoom lens 32 is “f1” and the lens position (shooting distance) of the focus lens 33 is “D4”, the lens control unit 36 By hot line communication, “K14” is transmitted to the camera control unit 21 as “K14” as the current position image plane movement coefficient K _cur , “K11” as the minimum image plane movement coefficient K _min , and “K19” as the maximum image plane movement coefficient K _max. To do.

  Here, FIG. 6 is a timing chart showing an example of hotline communication. FIG. 6A is a diagram illustrating a state in which hotline communication is repeatedly performed at predetermined intervals Tn. Also, FIG. 6B shows a state in which a certain communication period Tx is expanded in hot line communication repeatedly executed. Hereinafter, a scene in which the lens position of the focus lens 33 is communicated by hot line communication will be described based on the timing chart of FIG.

  The camera control unit 21 and the camera-side second communication unit 292 first output an L level signal to the signal line HREQ in order to start communication by hot line communication (T6). Then, the second lens-side communication unit 382 notifies the lens control unit 36 that this signal has been input to the electrical contact LP7. In response to this notification, the lens control unit 36 starts executing a generation process 501 that generates lens position data. The generation process 501 is a process in which the lens control unit 36 causes the focus lens encoder 332 to detect the position of the focus lens 33 and generates lens position data representing the detection result.

  When the lens control unit 36 completes the execution of the generation process 501, the lens control unit 36 and the second lens side communication unit 382 output an L level signal to the signal line HANS (T7). When this signal is input to the electrical contact BP8, the camera control unit 21 and the camera-side second communication unit 292 output the clock signal 502 from the electrical contact BP9 to the signal line HCLK.

  The lens control unit 36 and the second lens-side communication unit 382 output a lens position data signal 503 representing lens position data from the electrical contact LP10 to the signal line HDAT in synchronization with the clock signal 502. When the transmission of the lens position data signal 503 is completed, the lens control unit 36 and the second lens side communication unit 382 output an H level signal from the electrical contact LP8 to the signal line HANS (T8). Then, when this signal is input to the electrical contact BP8, the second camera-side communication unit 292 outputs an H level signal from the electrical contact LP7 to the signal line HREQ (T9).

  Note that command data communication and hotline communication can be executed simultaneously or in parallel.

  Next, the clip operation according to the present embodiment will be described with reference to FIG. In the present embodiment, in contrast AF search control, control is performed so that the moving speed of the image plane of the focus lens 33 is constant. The clip operation is an operation for suppressing the driving sound of the focus lens 33 in such contrast AF search control, and the speed of the focus lens 33 is reduced when the speed of the focus lens 33 becomes slow and the noise is prevented. Is clipped so as not to be less than the silent lower limit speed.

  In this embodiment, as will be described later, the camera control unit 21 of the camera body 2 uses a predetermined coefficient (Kc) to reduce the silent speed (the moving speed is constant) and the focus lens driving speed (the moving speed is constant). To determine whether or not the clip operation should be performed.

  When the clip operation is permitted by the camera control unit 21, the lens control unit 36 sets the drive speed of the focus lens 33 so that the drive speed V1b of the focus lens 33 described later does not become less than the silent lower limit lens moving speed V0b. Limited by the silent lower limit lens moving speed V0b. Hereinafter, this will be described in detail with reference to FIG.

  In step S101, the lens control unit 36 acquires the silent lower limit lens moving speed V0b. The silent lower limit lens moving speed V0b is stored in the lens memory 37, and the lens control unit 36 can acquire the silent lower limit lens moving speed V0b from the lens memory 37.

  In step S102, the lens control unit 36 acquires the drive instruction speed of the focus lens 33. In the present embodiment, the drive instruction speed of the focus lens 33 is transmitted from the camera control unit 21 to the lens control unit 36 by command data communication, whereby the lens control unit 36 receives the focus lens from the camera control unit 21. 33 drive instruction speeds can be acquired.

  In step S103, the lens control unit 36 compares the silent lower limit lens moving speed V0b acquired in step S101 with the drive instruction speed of the focus lens 33 acquired in step S102. Specifically, the lens control unit 36 determines whether or not the drive instruction speed (unit: pulses / second) of the focus lens 33 is less than the silent lower limit lens moving speed V0b (unit: pulses / second). When the driving instruction speed of the lens 33 is less than the silent lower limit lens moving speed, the process proceeds to step S104. On the other hand, when the driving instruction speed of the focus lens 33 is equal to or higher than the silent lower limit lens moving speed V0b, the process proceeds to step S105. move on.

  In step S104, it is determined that the drive instruction speed of the focus lens 33 transmitted from the camera body 2 is less than the silent lower limit lens moving speed V0b. In this case, the lens control unit 36 drives the focus lens 33 at the silent lower limit lens moving speed V0b in order to suppress the drive sound of the focus lens 33. Thus, when the drive instruction speed of the focus lens 33 is less than the silent lower limit lens moving speed V0b, the lens control unit 36 limits the lens driving speed V1b of the focus lens 33 with the silent lower limit lens moving speed V0b.

  On the other hand, in step S105, it is determined that the drive instruction speed of the focus lens 33 transmitted from the camera body 2 is equal to or higher than the silent lower limit lens moving speed V0b. In this case, since the driving sound of the focus lens 33 exceeding a predetermined value is not generated, the lens control unit 36 drives the focus lens 33 at the drive instruction speed of the focus lens 33 transmitted from the camera body 2.

  Here, FIG. 8 is a diagram for explaining the relationship between the lens driving speed V1b of the focus lens 33 and the silent lower limit lens moving speed V0b. As described above, the image plane movement coefficient K changes according to the lens position of the focus lens 33. Therefore, as shown in FIG. 8, when the focus lens 33 is driven so that the moving speed of the image plane is constant during focus detection, the lens drive speed V1b of the focus lens 33 is It changes according to the lens position of the lens 33. For example, in the example shown in FIG. 8, the image plane movement coefficient K is smaller toward the closest side, and the image plane movement coefficient K is larger toward the infinity side. Therefore, in the example shown in FIG. 8, when the focus lens 33 is driven so that the moving speed of the image plane becomes a constant speed, the lens moving speed V1b of the focus lens 33 becomes slower as it comes closer, and as it goes toward infinity. Get faster.

In this way, when the focus lens 33 is driven so that the moving speed of the image plane becomes a constant speed, if the clipping operation is not performed, the lens of the focus lens 33 as in the example shown in FIG. The drive speed V1b may be less than the silent lower limit lens moving speed V0b. For example, at the position of the focus lens 33 where the minimum image plane movement coefficient K _min is obtained (minimum image plane movement coefficient = 100 in FIG. 8), the lens movement speed V1b is less than the silent lower limit lens movement speed V0b.

  In particular, when the focal length of the lens barrel 3 is long or the light environment is bright, the lens moving speed V1b of the focus lens 33 tends to be less than the silent lower limit lens moving speed V0b. In such a case, the lens control unit 36 performs the clipping operation to limit the driving speed V1b of the focus lens 33 with the silent lower limit lens moving speed V0b as shown in FIG. 8 (from the silent lower limit lens moving speed V0b). (Step S104), and thus the driving sound of the focus lens 33 can be suppressed.

  Next, a clip operation control process for determining whether to permit or prohibit the clip operation shown in FIG. 7 will be described with reference to FIG. FIG. 9 is a flowchart showing clip operation control processing according to the present embodiment. Note that the clip operation control process described below is executed by the camera body 2 when, for example, the AF-F mode or the moving image shooting mode is set.

First, in step S201, the camera control unit 21 acquires lens information. Specifically, the camera control unit 21 sets the current image plane movement coefficient K _cur , the minimum image plane movement coefficient K _min , the maximum image plane movement coefficient K _max , and the silent lower limit lens movement speed V0b through the hotline communication. Obtained from the cylinder 3.

In step S202, the camera control unit 21 calculates the silent lower limit image plane moving speed V0a_max. The silent lower limit image plane moving speed V0a_max is a constant image plane moving speed. For example, when the focus lens 33 is driven so that the moving speed of the image plane is a constant speed, the minimum image plane moving coefficient is At the position of the focus lens 33 where K _min is obtained, the speed of the focus lens 33 is a speed at which the silent lower limit lens moving speed V0b is obtained. Hereinafter, the silent lower limit image plane moving speed V0a_max will be described in detail.

  FIG. 10 is a diagram for explaining the relationship between the moving speed V1a of the image plane during focus detection and the silent lower limit image plane moving speed V0a_max. The moving speed V1a of the image plane at the time of focus detection shown in FIG. 10 is the moving speed of the image plane when the focus lens 33 is driven at the lens driving speed V1b shown in FIG. 8, and in this embodiment, focus detection is performed. Since the driving of the focus lens 33 is controlled so that the moving speed of the image plane is sometimes constant, the moving speed V1a of the image plane at the time of focus detection is constant as shown in FIG.

  Further, the image plane moving speed V0a corresponding to the silent lower limit lens moving speed V0b shown in FIG. 10 is the moving speed of the image plane when the focus lens 33 is driven at the silent lower limit lens moving speed V0b shown in FIG. . Here, since the silent lower limit lens moving speed V0b is a constant lens moving speed, as shown in FIG. 10, when the image plane moving coefficient changes depending on the position of the focus lens 33, the silent lower limit lens moving speed. The image plane moving speed V0a corresponding to V0b also changes according to the position of the focus lens 33.

Furthermore, the silent lower limit image plane moving speed V0a_max shown in FIG. 10 is the position of the focus lens 33 that obtains the minimum image plane moving coefficient K _min out of the moving speed of the image plane (in the example shown in FIG. 10, the image plane moving coefficient K = 100), the moving speed of the focus lens 33 is a speed at which the lower limit lens moving speed V0b is reached. That is, the silent lower limit image plane moving speed V0a_max is the maximum image plane moving speed V0a_max among the image plane moving speeds V0a corresponding to the silent lower limit lens moving speed V0b.

As described above, in the present embodiment, the maximum image plane movement speed (the image plane movement coefficient is the minimum) among the image plane movement speeds corresponding to the silent lower limit lens movement speed V0b, which changes according to the lens position of the focus lens 33. Is calculated as a silent lower limit image plane moving speed V0a_max. For example, in the example shown in FIG. 10, since the minimum image plane movement coefficient K _min is “100”, the image plane movement speed at the lens position of the focus lens 33 where the image plane movement coefficient is “100” is set as the silent lower limit image. Calculated as the surface moving speed V0a_max.

Specifically, the lens control unit 36, as shown in the following formula (4), quiet lower lens moving speed V0b (unit: pulse / s) minimum image plane shift factor and K _min (unit: pulse / mm) and Based on the above, the silent lower limit image plane moving speed V0a_max (unit: mm / second) is calculated.
Silent lower limit image plane moving speed V0a_max = Silent lower limit lens moving speed V0b / Minimum image plane moving coefficient K _min (4)

Thus, in the present embodiment, by using the minimum image plane shift factor K _min, by calculating the quiet lower image plane movement velocity V0a_max, at the timing of starting the focus detection and video recording by AF-F, quiet limit The image plane moving speed V0a_max can be calculated. For example, in the example shown in FIG. 10, the image plane moving speed at the lens position of the focus lens 33 at which the image plane moving coefficient K is “100” at the timing t1 when the focus detection by AF-F or moving image shooting is started is expressed as silent. It can be calculated as the lower limit image plane moving speed V0a_max.

In step S203, the camera control unit 21 compares the focus detection image plane moving speed V1a acquired in step S201 with the silent lower limit image plane moving speed V0a_max calculated in step S202. Specifically, the camera control unit 21 determines that the focus detection image plane moving speed V1a (unit: mm / sec) and the silent lower limit image plane moving speed V0a_max (unit: mm / sec) are expressed by the following equation (5). It is determined whether or not the above is satisfied.
(Focus detection image plane moving speed V1a × Kc)> Silent lower limit image plane moving speed V0a_max ... (5)
In the above equation (5), the coefficient Kc is a value of 1 or more (Kc ≧ 1), and details thereof will be described later.

  If the above equation (5) is satisfied, the process proceeds to step S204, and the lens controller 36 permits the clip operation shown in FIG. That is, in order to suppress the drive sound of the focus lens 33, as shown in FIG. 8, the drive speed V1b of the focus lens 33 is limited to the silent lower limit lens moving speed V0b (the drive speed V1b of the focus lens 33 is lower than the silent lower limit). Search control is performed so as not to be lower than the lens moving speed V0b.)

  On the other hand, if the above equation (5) is not satisfied, the process proceeds to step S205, and the clip operation shown in FIG. 7 is prohibited. In other words, the focusing speed is not limited by the lower limit lens moving speed V0b of the silent lens 33 (the driving speed V1b of the focusing lens 33 is allowed to be lower than the lower moving speed of the silent lens V0b), and focusing is performed. The focus lens 33 is driven so that the image plane moving speed V1a can be detected appropriately.

  Here, if the above equation (5) is not satisfied, if the clip operation is permitted and the drive speed of the focus lens 33 is limited by the silent lower limit lens moving speed V0b, the moving speed of the image plane is the same. In some cases, the focal point detection speed is faster than the focus detection image plane moving speed V1a, and appropriate focusing accuracy cannot be obtained. On the other hand, in the case where the above formula (5) is satisfied, the clipping operation is prohibited and the focus lens 33 is driven so that the moving speed of the image plane becomes the image plane moving speed V1a for focus detection. As shown in FIG. 8, the driving speed V1b of the focus lens 33 becomes lower than the silent lower limit lens moving speed V0b, and a driving sound of a predetermined value or more may be generated.

  As described above, when the image plane moving speed V1a for focus detection is less than the silent lower limit image plane moving speed V0a_max, the focus lens 33 is obtained so that the image plane moving speed V1a that can appropriately detect the in-focus position is obtained. Is driven at a lens driving speed less than the silent lower limit lens moving speed V0b, or in order to suppress the driving sound of the focus lens 33, the focus lens 33 is driven at a lens driving speed equal to or higher than the silent lower limit lens moving speed V0b. It becomes.

  Therefore, in the present embodiment, when the coefficient Kc in the above equation (5) satisfies the above equation (5) even when the focus lens 33 is driven at the silent lower limit lens moving speed V0b, a certain focus detection accuracy is obtained. Is stored as a value of 1 or more that can be secured. Thereby, as shown in FIG. 10, the lens control unit 36 satisfies the above formula (5) even when the focus detection image plane moving speed V1a is less than the silent lower limit image plane moving speed V0a_max. It is determined that a certain focus detection accuracy can be ensured, and the clip operation for driving the focus lens 33 at a lens driving speed lower than the silent lower limit lens moving speed V0b is given with priority given to the suppression of the driving sound of the focus lens 33.

  On the other hand, if the image plane moving speed V1a × Kc (where Kc ≧ 1) for focus detection is equal to or lower than the silent lower limit image plane moving speed V0a_max, the clipping operation is permitted and the driving speed of the focus lens 33 is set to silent. When limited by the lower limit lens moving speed V0b, the image plane moving speed for focus detection becomes too fast, and focus detection accuracy may not be ensured. Therefore, when the above formula (5) is not satisfied, the lens controller 36 gives priority to the focus detection accuracy and prohibits the clip operation shown in FIG. Thereby, at the time of focus detection, the moving speed of the image plane can be set to the image plane moving speed V1a that can appropriately detect the in-focus position, and the focus detection can be performed with high accuracy.

  When the aperture value is large (diaphragm aperture is small), the depth of field becomes deep, and the sampling interval at which the in-focus position can be appropriately detected becomes wide. As a result, it is possible to increase the image plane moving speed V1a at which the in-focus position can be detected appropriately. Therefore, when the image plane moving speed V1a at which the in-focus position can be appropriately detected is a fixed value, the lens control unit 36 increases the coefficient Kc of the above equation (5) as the aperture value increases. can do.

  Similarly, when the image size is small, such as a live view image (when the compression ratio of the image is high or when the pixel data thinning rate is high), high focus detection accuracy is not required, so the coefficient of the above equation (5) Kc can be increased. In addition, when the pixel pitch in the image sensor 22 is wide, the coefficient Kc in the above equation (5) can be increased.

  Next, with reference to FIG. 11 and FIG. 12, the control of the clip operation will be described in more detail. FIG. 11 is a diagram showing the relationship between the moving speed V1a of the image plane at the time of focus detection and the clipping operation, and FIG. 12 is for explaining the relationship between the lens driving speed V1b of the focus lens 33 and the clipping operation. FIG.

  For example, as described above, in this embodiment, when the search control is started with a half-press of the release switch as a trigger, and when the search control is started with a condition other than the half-press of the release switch as a trigger, The moving speed of the image plane in the search control may differ depending on the moving image shooting mode, the sports shooting mode and the landscape shooting mode, or the focal length, shooting distance, aperture value, and the like. FIG. 11 illustrates the moving speeds V1a_1, V1a_2, and V1a_3 of three different image planes.

  Specifically, the image plane moving speed V1a_1 at the time of focus detection shown in FIG. 11 is the maximum moving speed among the moving speeds of the image plane that can appropriately detect the focus state, and satisfies the relationship of the above formula (5). This is the moving speed of the image plane. Further, the image plane moving speed V1a_2 at the time of focus detection is an image plane moving speed slower than V1a_1, but is an image plane moving speed that satisfies the relationship of the above formula (5) at timing t1. On the other hand, the image plane moving speed V1a_3 at the time of focus detection is an image plane moving speed that does not satisfy the relationship of the above formula (5).

  In this manner, in the example shown in FIG. 11, when the moving speed of the image plane at the time of focus detection is V1a_1 and V1a_2, the clip operation shown in FIG. Is allowed. On the other hand, when the moving speed of the image plane at the time of focus detection is V1a_3, the clip operation shown in FIG. 7 is prohibited because the relationship of the above equation (5) is not satisfied.

  This point will be specifically described with reference to FIG. In FIG. 12, V1b_1 is a lens driving speed of the focus lens 33 corresponding to the maximum moving speed V1a_1 of the image plane capable of appropriately detecting the focus state shown in FIG. That is, V1b_1 is the drive speed of the focus lens 33 when the drive of the focus lens 33 is controlled so that the moving speed of the image plane at the time of focus detection becomes V1a_1. Further, as shown in FIG. 11, V1b_2 is the lens driving speed of the focus lens 33 corresponding to the image plane moving speed V1a_2 that satisfies the relationship of the above formula (5), and V1b_3 is as shown in FIG. This is the lens driving speed of the focus lens 33 corresponding to the image plane moving speed V1a_3 that does not satisfy the relationship of the above expression (5).

  As described above, since the image plane moving speed V1a_1 corresponding to the lens driving speed V1b_1 of the focus lens 33 satisfies the relationship of the above formula (5), the clipping operation is permitted. However, in the example shown in FIG. 12, the lens driving speed V1b_1 is not less than the silent lower limit lens moving speed V0b even at the lens position where the minimum image plane movement coefficient (K = 100) is obtained. No action is taken.

  Further, since the image plane moving speed V1a_2 corresponding to the lens driving speed V1b_2 of the focus lens 33 also satisfies the relationship of the above formula (5) at the timing t1, the clipping operation is permitted. In the example shown in FIG. 12, when the focus lens 33 is driven at the lens driving speed V1b_2 so that the moving speed of the image plane at the time of focus detection is V1a_2, at the lens position where the image plane moving coefficient K is K1. Since the lens driving speed V1b_1 is lower than the silent lower limit lens moving speed V0b, the driving speed V1b_2 of the focus lens 33 is limited by the silent lower limit lens moving speed V0b at the lens position where the image plane movement coefficient K is smaller than K1.

  That is, the image plane moving speed V1a_2 is a constant speed until the lens position at which the lens driving speed V1b_2 of the focus lens 33 becomes the silent lower limit lens moving speed V0b, but the lens driving speed V1b_2 of the focus lens 33 becomes the silent lower limit lens moving. When the speed is less than V0b, the clipping operation is performed. As a result, the moving speed V1a_2 of the image plane at the time of focus detection is different from the moving speed (search speed) of the image plane so far. The focus evaluation value search control is performed. That is, as shown in FIG. 11, at the lens position where the image plane movement coefficient is smaller than K1, the image plane moving speed V1a_2 at the time of focus detection is different from the constant speed so far.

  Further, since the image plane moving speed V1a_3 corresponding to the lens driving speed V1b_3 of the focus lens 33 does not satisfy the relationship of the above formula (5), the clipping operation is prohibited. Therefore, in the example shown in FIG. 12, when the focus lens 33 is driven at the lens driving speed V1b_3 so that the moving speed of the image plane becomes a constant image plane moving speed V1a_3, the image plane moving coefficient K is K2. At the lens position, the lens driving speed V1b_3 is lower than the silent lower limit lens moving speed V0b, but the clip operation is not performed at the lens position where the image plane movement coefficient K smaller than K2 is obtained, and the focus state is detected appropriately. Therefore, the driving speed V1b_3 of the focus lens 33 is set to be lower than the silent lower limit lens moving speed V0b.

  As described above, in the present embodiment, the maximum image plane moving speed among the image plane moving speeds when the focus lens 33 is driven at the silent lower limit lens moving speed V0b is calculated as the silent lower limit image plane moving speed V0a_max. The calculated silent lower limit image plane moving speed V0a_max is compared with the image plane moving speed V1a at the time of focus detection. When the image plane moving speed V1a × Kc (where Kc ≧ 1) at the time of focus detection is faster than the silent lower limit image plane moving speed V0a_max, the focus lens 33 is driven at the silent lower limit lens moving speed V0b. Even in such a case, it is determined that a certain level of focus detection accuracy can be obtained, and the clipping operation shown in FIG. Thereby, in this embodiment, the drive sound of the focus lens 33 can be suppressed while ensuring focus detection accuracy.

  On the other hand, when the moving speed V1a × Kc (where Kc ≧ 1) of the image plane at the time of focus detection is equal to or lower than the silent lower limit image plane moving speed V0a_max, the driving speed V1b of the focus lens 33 is set to the silent lower limit lens moving speed V0b. If limited, appropriate focus detection accuracy may not be obtained. Therefore, in this embodiment, in such a case, the clip operation shown in FIG. 7 is prohibited so that an image plane moving speed suitable for focus detection can be obtained. Thereby, in this embodiment, a focus position can be detected appropriately at the time of focus detection.

Further, in this embodiment stores in advance the minimum image plane shift factor K _min in the lens memory 37 of the lens barrel 3, with the minimum image plane shift factor K _min, quiet lower image plane movement velocity V0a_max calculate. Therefore, in the present embodiment, for example, as shown in FIG. 10, at the time t1 when the focus detection in the moving image shooting or the AF-F mode is started, the image plane moving speed V1a × Kc for focus detection (however, It is possible to determine whether or not the clip operation is performed by determining whether or not Kc ≧ 1) exceeds the silent lower limit image plane moving speed V0a_max. As described above, in this embodiment, the current position image plane movement coefficient K _cur is not used to repeatedly determine whether or not to perform the clip operation, but the minimum image plane movement coefficient K _min is used to _record a moving image. Since it is possible to determine whether or not to perform the clip operation at the first timing when focus detection in the AF-F mode is started, the processing load on the camera body 2 can be reduced.

  The embodiment described above is described for facilitating the understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, in the above-described embodiment, the configuration in which the clip operation control process illustrated in FIG. 7 is executed in the camera body 2 is exemplified. However, the configuration is not limited to this configuration. For example, the clip operation control process illustrated in FIG. It is good also as a structure performed in the lens-barrel 3. FIG.

In the above-described embodiment, as shown in the above equation (3), the image plane movement coefficient K is calculated by the image plane movement coefficient K = (drive amount of the focus lens 33 / image plane movement amount). Although illustrated, it is not limited to this structure, For example, it is good also as a structure calculated as shown in following formula (6).
Image plane movement coefficient K = (Movement amount of image plane / Driving amount of focus lens 33) (6)
In this case, the lens control unit 36 can calculate the silent lower limit image plane moving speed V0a_max as follows. That is, as shown in the following formula (7), the lens control unit 36 has a silent lower limit lens moving speed V0b (unit: pulses / second) and an image plane movement coefficient K at each lens position (focal length) of the zoom lens 32. Of these, based on the maximum image plane movement coefficient K _max (unit: pulses / mm) indicating the maximum value, the silent lower limit image plane movement speed V0a_max (unit: mm / second) can be calculated.
Silent lower image plane movement velocity V0a_max = silent lower lens moving speed V0b / maximum image plane shift factor K _max ··· (7)
For example, when the value calculated by “the amount of movement of the image plane / the amount of drive of the focus lens 33” is used as the image plane movement coefficient K, the larger the value (absolute value), the larger the value of the focus lens (the predetermined value ( For example, the amount of movement of the image plane when driving is increased. When the value calculated by “the driving amount of the focus lens 33 / the moving amount of the image plane” is adopted as the image plane movement coefficient K, the larger the value (absolute value), the larger the value of the focus lens (for example, 1 mm). ) The amount of movement of the image plane when driven becomes small.
The lens memory 37 is not limited to storing the image plane movement coefficient K as long as the maximum image plane movement coefficient _Kmax can be transmitted. For example, the maximum image plane movement coefficient K _max may be calculated according to the zoom lens position and the like, and the calculated maximum image plane movement coefficient K _max may be transmitted to the camera body 2. Similarly, the minimum image plane movement coefficient K _min may be calculated according to the zoom lens position and the like, and the calculated minimum image plane movement coefficient K _min may be transmitted to the camera body 2.
Further, the image plane movement coefficient K and the maximum image plane movement coefficient K _max stored in the lens memory 37 may be integers, values including a decimal point, or indices. Or a logarithm. Further, the image plane movement coefficient K and the maximum image plane movement coefficient K _max may be decimal numbers, binary numbers, or the like.
Further, if the maximum image plane movement coefficient K _max is transmitted to the camera body 2, the electrical contact of the mount portion 401 of the camera body 2 and the electrical contact of the mount portion 402 of the lens barrel 3 are connected. It is not limited. For example, the maximum image plane movement coefficient K _max may be transmitted from the lens barrel 3 to the camera body 2 using wireless communication.

In addition to the above-described embodiment, when the silent mode for suppressing the driving sound of the focus lens 33 is set, the above-described clipping operation and the clipping operation control process are executed, and the silent mode is not set. Alternatively, the clip operation and the clip operation control process described above may not be executed. Further, when the silent mode is set, priority is given to suppression of the driving sound of the focus lens 33, and the clip operation shown in FIG. 7 may be always performed without performing the clip operation control process shown in FIG. .
In the above-described embodiments, the image plane movement coefficient K = (drive amount of the focus lens 33 / movement amount of the image plane) has been described. However, the present invention is not limited to this. For example, when the image plane movement coefficient K = (image plane movement amount / drive amount of the focus lens 33) is defined, the maximum image plane movement coefficient Kmax is used to perform a clip operation or the like as in the above-described embodiment. You can control.

  Furthermore, in the above-described embodiment, the configuration in which the present invention is applied to a single-lens reflex digital camera is illustrated as shown in FIG. 1, but the present invention is not limited to this configuration. For example, as shown in FIG. May be applied to a mirrorless camera with interchangeable lenses. In the example shown in FIG. 13, the camera body 2 a sequentially sends captured images captured by the image sensor 22 to the camera control unit 21, and passes through the liquid crystal drive circuit 25 to the electronic viewfinder (EVF) 26 of the observation optical system. indicate. In this case, for example, the camera control unit 21 reads the output of the image sensor 22 and calculates the focus evaluation value based on the read output, thereby detecting the focus adjustment state of the photographing optical system by the contrast detection method. be able to. Further, the present invention may be applied to other optical devices such as a digital video camera, a lens-integrated digital camera, and a mobile phone camera.

DESCRIPTION OF SYMBOLS 1 ... Digital camera 2 ... Camera body 21 ... Camera control part 22 ... Imaging device 29 ... Camera transmission / reception part 291 ... Camera side 1st communication part 292 ... Camera side 2nd communication part 3 ... Lens barrel 32 ... Zoom lens lens 321 ... Zoom lens drive motor 33 ... focus lens 331 ... focus lens drive motor 36 ... lens control unit 37 ... lens memory 38 ... lens transmission / reception unit 381 ... lens side first communication unit 382 ... lens side second communication unit

Claims (4)

A drive unit for driving an optical system including a focusing optical system;
An image plane movement coefficient corresponding to an amount of movement of the image plane with respect to an amount of movement of the focus adjustment optical system, the first image plane movement coefficient determined corresponding to the position of the focus adjustment optical system; and the focus adjustment A transmitter that transmits a second image plane movement coefficient that maximizes the amount of movement of the image plane relative to the amount of movement of the focus adjustment optical system within the driving range of the optical system;
The driving speed of the focus adjustment optical system determined by the imaging device based on the first image plane movement coefficient and the second image plane movement coefficient, wherein the image plane by the focus adjustment optical system is at a constant speed. A receiving unit for receiving a driving speed for moving from the imaging device;
When the received drive speed is slower than a predetermined speed, the drive unit drives the focus adjustment optical system at a speed different from the received drive speed. The interchangeable lens according to claim 1,
The drive unit is an interchangeable lens that drives the focus adjustment optical system at the predetermined speed when the received drive speed is slower than a predetermined speed. The interchangeable lens according to claim 1 or 2,
It said first image plane shift factor and the second image plane shift factor is the amount of movement of the optical axis of the focusing optical system and T _L, the movement amount of the image plane in the case of the T _I, and T _L Is a coefficient corresponding to the ratio to T _I ,
The interchangeable lens, wherein the second image plane movement coefficient is a value that maximizes T _I / T _L. The interchangeable lens according to any one of claims 1 to 3,
An interchangeable lens in which, when the focus adjustment optical system is driven at a speed higher than the predetermined speed, the driving sound is smaller than when the focus adjustment optical system is driven at a speed slower than the predetermined speed.

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