JP6465151B2 - interchangeable lens - Google Patents

Description

  The present invention relates to an interchangeable lens.

  2. Description of the Related Art Conventionally, a technique for detecting a focus state of an optical system by calculating an evaluation value related to contrast by the optical system while driving the focus adjustment lens at a predetermined driving speed in the optical axis direction is known (for example, Patent Document 1).

JP 2010-139666 A

  The problem to be solved by the present invention is to provide an interchangeable lens capable of suitable imaging.

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

  [1] An interchangeable lens according to a first aspect of the present invention is an interchangeable lens attached to a camera body, and includes an optical system including a focus adjustment lens, and driving the focus adjustment lens in the optical axis direction of the optical system. And a first value at the lens position of the focus adjustment lens, which changes depending on the position of the driving unit and the focus adjustment lens, and corresponds to the movement amount of the image plane relative to the movement amount of the focus adjustment lens. And a second value that is a value in the vicinity of the image plane movement coefficient that maximizes the amount of movement of the image plane relative to the amount of movement of the focus adjustment lens within the drive range of the focus adjustment lens by the drive unit, A transmission unit for transmitting to the camera body.

  ADVANTAGE OF THE INVENTION According to this invention, the interchangeable lens which can image suitably can be provided.

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 diagram illustrating a driving range of the focus lens 33. FIG. 4 is a table showing the relationship between the lens position (focal length) of the zoom lens and the lens position (shooting distance) of the focus lens and the image plane movement coefficient K according to the first embodiment. FIG. 5 is a schematic diagram illustrating details of the connection units 202 and 302. FIG. 6 is a diagram illustrating an example of command data communication. FIG. 7 is a diagram illustrating an example of hotline communication. FIG. 8 is a flowchart showing an operation example of this embodiment. FIG. 9 is a table showing the relationship between the lens position (focal length) of the zoom lens and the lens position (shooting distance) of the focus lens and the image plane movement coefficient K according to the second embodiment. FIG. 10 is a diagram for explaining the play amount G of the drive transmission mechanism of the focus lens 33. FIG. 11 is a diagram illustrating the relationship between the focus lens position and the focus evaluation value and the relationship between the focus lens position and time when performing focus driving based on the scanning operation and the contrast detection method according to the present embodiment. is there. FIG. 12 is a flowchart showing the operation of the fourth embodiment. FIG. 13 is a flowchart showing the clip operation according to the fifth embodiment. FIG. 14 is a diagram for explaining the relationship between the lens driving speed V1a of the focus lens and the silent lower limit lens moving speed V0b. FIG. 15 is a flowchart showing clip operation control processing according to the fifth embodiment. FIG. 16 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 V0b_max. FIG. 17 is a diagram illustrating the relationship between the moving speed V1a of the image plane during focus detection and the clipping operation. FIG. 18 is a diagram for explaining the relationship between the lens driving speed V1a of the focus lens and the clipping operation. FIG. 19 is 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 used in the sixth embodiment. FIG. 20 is a main part configuration diagram showing a camera according to another embodiment.

<< First 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 adjust the focal length of the photographing optical system by moving in the direction of the optical axis L1. 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 36. 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 the correspondence between the driving amount of the focus lens 33 and the moving amount of the image plane, and is, for example, the ratio between the driving amount of the focus lens 33 and the moving amount of the image plane. The details of the image plane movement coefficient K stored in the lens memory 37 will be described later.

  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.

  The camera control unit 21 detects the focus adjustment state of the photographing optical system by the contrast detection method (hereinafter, referred to as “contrast AF” as appropriate) 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 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 sampling interval of the focus evaluation value increases, the variation of the focus position increases and the focus accuracy may decrease. 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, wobbling, a proximity search that searches only the vicinity of a predetermined position (neighbor scan), and a global search that searches the entire drive range of the focus lens 33 (global scan).

  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. Furthermore, the driving speed of the focus lens 33 in search control may be changed according to the focal length, the shooting distance, the aperture value, and the like.

  In the present embodiment, focus detection by a phase difference detection method can also be performed. Specifically, the camera body 2 includes a focus detection module 261, and the focus detection module 261 is disposed in the vicinity of the planned focal plane of the imaging optical system and the microlens. It has a pair of line sensors (not shown) in which a plurality of pixels having photoelectric conversion elements are arranged. 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 of 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 known correlation calculation.

  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, the drive range of the focus lens 33 will be described with reference to FIG.

  As shown in FIG. 3, the focus lens 33 is configured to be movable in the infinity direction 410 and the closest direction 420 on the optical axis L <b> 1 indicated by a one-dot chain line in the drawing. Stoppers (not shown) are provided at the mechanical end points (mechanical end points) 430 in the infinite direction 410 and the mechanical end points 440 in the closest direction 420 to restrict the movement of the focus lens 33. That is, the focus lens 33 is configured to be movable from a mechanical end point 430 in the infinity direction 410 to a mechanical end point 440 in the closest direction 420.

  However, the range in which the lens control unit 36 actually drives the focus lens 33 is smaller than the range from the mechanical end point 430 to the mechanical end point 440 described above. More specifically, the moving range of the lens control unit 36 is determined from the infinite soft limit position 450 provided on the inner side of the mechanical end point 430 in the infinity direction 410 to the inner side of the mechanical end point 440 in the closest direction 420. The focus lens 33 is driven in the range up to the provided closest soft limit position 460. That is, the lens driving unit 212 drives the focus lens 33 between the closest soft limit position 460 corresponding to the closest drive limit position and the infinite soft limit position 450 corresponding to the infinity drive limit position.

The infinite soft limit position 450 is provided outside the infinite focus position 470. The infinite focus position 470 is the position of the focus lens 33 corresponding to the position on the most infinite side where the photographing optical system including the lenses 31, 32, 33, 34 and the diaphragm 35 can be focused. The reason why the infinite soft limit position 450 is provided at such a position is that a focus evaluation value peak may exist at the infinite focus position 470 when performing focus detection by the contrast detection method. That is, if the infinite focus position 470 is matched with the infinite soft limit position 450, there is a problem that the peak of the focus evaluation value existing at the infinite focus position 470 cannot be recognized as a peak. Therefore, the infinite soft limit position 450 is provided outside the infinite focusing position 470. Similarly, the closest soft limit position 460 is provided outside the closest focus position 480. Here, the closest focus position 480 is the position of the focus lens 33 corresponding to the closest position where the photographing optical system including the lenses 31, 32, 33, 34 and the diaphragm 35 can be focused.
The closest focus position 480 can be set using, for example, aberration. For example, even if the focus lens 33 can be focused by driving the focus lens 33 closer to the closest focus position 480 than the set close focus position 480, if the aberration deteriorates, it is not appropriate as the lens usage range. Because there is no.

  In the present embodiment, the position of the focus lens 33 can be represented by, for example, the number of pulses of the drive signal given to the lens drive motor 321. can do. For example, in the example shown in FIG. 5, the infinite soft limit position 450 is a position of “−100 pulses”, the closest focusing position 480 is a position of “9800 pulses”, and the closest soft limit position 460 is a position of “9900 pulses”. . In this case, in order to move the focus lens 33 from the infinite soft limit position 450 to the closest soft limit position 460, it is necessary to supply a drive signal for 10,000 pulses to the lens drive motor 321. However, in this embodiment, it is not specifically limited to such an aspect.

  Next, the image plane movement coefficient K stored in the lens memory 37 of the lens barrel 3 will be described.

The image plane movement coefficient K is a value indicating the correspondence between the driving amount of the focus lens 33 and the moving amount of the image plane, and is, for example, the ratio between the driving amount of the focus lens 33 and the moving amount of the image plane. In the present embodiment, the image plane movement coefficient is obtained by, for example, the following equation (1). 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) (1)
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 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 zoom lens 32, that is, the focal length. 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. 4 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. 4, the drive area of the zoom lens 32 is divided into nine areas “f1” to “f9” in order from the wide end to the tele end, and the drive area 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”. Here, among the lens positions of the focus lens 33, “D1” is a predetermined area corresponding to the closest focus position 480 shown in FIG. For example, it is a predetermined area in the vicinity of the closest focus position 480 shown in FIG. “D9” is a predetermined area corresponding to the infinite focus position 470 shown in FIG. For example, it is a predetermined area near the infinite focus position 470 shown in FIG. In the table shown in FIG. 4, 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 becomes “K11”. The table shown in FIG. 4 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. For example, in FIG. 4, “K11” = “100”, “K12” = “200”, “K13” = “300”, “K14” = “400”, “K15” = “500”, “K16” = When “600”, “K17” = “700”, “K18” = “800”, “K19” = “900”, the minimum value “K11” = “100” is the minimum image plane movement coefficient. K _min , and the maximum value “K19” = “900” is the maximum image plane movement coefficient K _max .
The minimum image plane movement coefficient K _min usually changes according to the current lens position of the zoom lens 32. Further, the minimum image plane movement coefficient K _min is generally 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 (fixed value) that is normally determined according to the lens position (focal length) of the zoom lens 32 and depends on the lens position (shooting distance) of the focus lens 33. Not a value.

Here, in the present embodiment, among the lens positions of the focus lens 33, the image plane movement coefficient K at “D1” is set to the minimum image plane movement coefficient _Kmin . That is, in this embodiment, the closest in-focus position 480 near containing the closest in-focus position 480 shown in FIG. 3, in the case of driving the focusing lens 33, the image plane shift factor K, the minimum image plane shift factor K _min In FIG. 4, “K11”, “K21”, “K31”, “K41”, “K51”, “K61”, “K71”, “K81”, “K91” shown in gray "Indicates a minimum image plane movement coefficient K _min indicating a minimum value among the image plane movement coefficients K at each lens position (focal length) of the zoom lens 32.

For example, 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, when the lens position (focal length) of the zoom lens 32 is “f2”, the image plane movement coefficient K is “when the lens position (shooting distance) of the focus lens 33 is“ D1 ”. “K21” indicates the smallest value among “K21” to “K29”, which are 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”, “K51”, “K61”, “K” shown in gray “K71”, “K81”, and “K91” are the minimum image plane movement coefficients K _min , respectively.

Thus, in the present embodiment, the image plane movement coefficient K at “D1” among the lens positions of the focus lens 33 is set to the minimum image plane movement coefficient K _min . In particular, although depending on the configuration of 31, 32, 33, and 34 constituting the lens barrel 3, in the present embodiment, when the focus lens 33 is driven from the infinity side toward the close side, the image is displayed. The surface movement coefficient K tends to be small, and the image plane movement coefficient K tends to be the smallest at the closest focus position 480 shown in FIG. Therefore, in the present embodiment, the image plane movement coefficient K at “D1” is set as the minimum image plane movement coefficient K _min . However, depending on the configuration of 31, 32, 33, and 34 constituting the lens barrel 3, the image plane movement coefficient K may be the smallest at the infinite focus position 470 shown in FIG. In this case, the image plane movement coefficient K at “D9” can be set to 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 usually changes according to the current lens position of the zoom lens 32. Further, the maximum image plane movement coefficient K _max is generally 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.

Here, in the present embodiment, among the lens positions of the focus lens 33, the image plane movement coefficient K at “D9” is set to the maximum image plane movement coefficient _Kmax . That is, in this embodiment, in the infinite focus position 470 near containing an infinite focusing position 470 shown in FIG. 3, in the case of driving the focusing lens 33, the image plane shift factor K, the maximum image plane shift factor K _max In FIG. 4, the hatched “K19”, “K29”, “K39”, “K49”, “K59”, “K69”, “K79”, “K89”, “K99” indicates a maximum image plane movement coefficient K _max indicating a maximum value among the image plane movement coefficients K at each lens position (focal length) of the zoom lens 32.

As described above, in the present embodiment, among the lens positions of the focus lens 33, the image plane movement coefficient K at “D9” is set to the maximum image plane movement coefficient _Kmax . In particular, although depending on the configuration of 31, 32, 33, and 34 constituting the lens barrel 3, in the present embodiment, when the focus lens 33 is driven from the closest side toward the infinity side, The surface movement coefficient K tends to increase, and the image plane movement coefficient K tends to become the largest at the infinite focus position 470 shown in FIG. Therefore, in the present embodiment, the image plane movement coefficient K at “D9” is set as the maximum image plane movement coefficient K _max . However, depending on the configurations of 31, 32, 33, and 34 constituting the lens barrel 3, the image plane movement coefficient K may be maximized at the closest focus position 480 shown in FIG. In this case, the image plane movement coefficient K at “D1” can be set to the maximum image plane movement coefficient K _max .

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 is smallest in place of the minimum image plane shift factor K _min indicating the value, the minimum image plane shift factor K is a value in the vicinity of the minimum image plane shift factor K _min of the image plane shift factor K _“min ′” may be stored in the lens memory 37. For example, when the value of the minimum image plane movement coefficient K _min is a large number of digits of 102.345, 100, which is a value in the vicinity of 102.345, may be stored as the minimum image plane movement coefficient K _min ′. it can. When 100 (minimum image plane movement coefficient K _min ′) is stored in the lens memory 37, the memory capacity of the memory is larger than when 102.345 (minimum image plane movement coefficient K _min ) is stored in the lens memory 37. This is because saving can be achieved and the capacity of transmission data can be suppressed during transmission to the camera body 2.
Further, for example, when the value of the minimum image plane movement coefficient K _min is 100, 100 is considered in consideration of the stability of control such as backlash control, silent control (clip operation), lens speed control and the like which will be described later. 98, which is a value in the vicinity of, can be stored as the minimum image plane movement coefficient K _min ′. For example, when considering the control stability, it is preferable to set the minimum image plane movement coefficient K _min ′ within the range of 80% to 120% of the actual value (minimum image plane movement coefficient K _min ).

  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 surface side of the body side mount portion 201 is provided in the vicinity of the body side mount portion 201 (inner surface side of the body side mount portion 201). . The connection portion 202 is provided with a plurality of electrical contacts.

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

  When the lens barrel 3 is attached to the camera body 2, an electrical contact of the connection portion 202 provided on the body side mount portion 201 and an electrical contact of the connection portion 302 provided on the lens side mount portion 301 are obtained. Electrically and physically connected. 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. 5 is a schematic diagram illustrating details of the connection units 202 and 302. In FIG. 5, 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 mount surface of the body side mount portion 201 (a location on the right side of the body side mount portion 201 in FIG. 5). 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. 5, twelve electrical contacts BP <b> 1 to BP <b> 12 exist in the connection unit 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 (except for circuits with relatively large power consumption such as the lens drive 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. 5 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. 6 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 501 to the lens-side first communication unit 291 using the signal line CLK. . In addition, the camera control unit 21 and the camera-side first communication unit 291 use the signal line BDAT in synchronization with the clock signal 501 to transmit the camera-side command packet signal 502 as control data to the lens-side first communication unit 291. Send to. When the clock signal 501 is output, the lens control unit 36 and the lens side first communication unit 381 synchronize with the clock signal 501 and use the signal line LDAT to transmit the lens side command packet signal as response data. 503 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 503 (T2). Then, the lens control unit 36 starts the first control process 504 according to the content of the body side command packet signal 502 received up to time T2.

  For example, when the received body-side command packet signal 502 is a content requesting specific data on the lens barrel 3 side, the lens control unit 36 uses the content of the command packet signal 502 as the first control processing 504. Along with the analysis, a process for generating the requested specific data is executed. Further, as the first control processing 504, the lens control unit 36 uses the checksum data included in the command packet signal 502 to simplify whether or not there is an error in the communication of the command packet signal 502 from the number of data bytes. A communication error check process is also executed. The specific data signal generated in the first control process 504 is output to the camera body 2 side as a lens-side data packet signal 507 (T3). In this case, the camera-side data packet signal 506 output from the camera body 2 after the command packet signal 502 is dummy data (including checksum data) that is not particularly meaningful 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 506 as the second control process 508 (T4).

  For example, when the camera-side command packet signal 502 is a drive instruction for the focus lens 33 and the camera-side data packet signal 506 is the drive speed and drive amount of the focus lens 33, the lens control unit 36 As the control process 504, the contents of the command packet signal 502 are analyzed, and a confirmation signal indicating that the contents are understood is generated (T2). The confirmation signal generated in the first control process 504 is output to the camera body 2 as a lens-side data packet signal 507 (T3). In addition, as the second control process 508, the lens control unit 36 analyzes the contents of the camera-side data packet signal 506 and executes a communication error check process using the checksum data included in the camera-side data packet signal 506. (T4). After the completion of the second control processing 508, the lens control unit 36 drives the focus lens drive motor 331 based on the received camera side command packet signal 506, 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 508 is completed, the lens control unit 36 notifies the lens-side first communication unit 291 that the second control process 508 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 control unit 21 and the camera side first communication unit 291 transmit the camera side command packet signal 502 and the camera side data packet signal 506 one by one. 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 502 and the camera side are transmitted. Two data packet signals 506 constitute one control data.

  Similarly, in one command data communication, the lens control unit 36 and the lens side first communication unit 381 transmit the lens side command packet signal 503 and the lens side data packet signal 507 one by one. 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 503 and the lens side data packet signal 507. 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. Returning to FIG. 5, the lens control unit 36 includes a signal line HREQ including the electrical contacts BP7 and LP7, a signal line HANS including the electrical contacts BP8 and LP8, and a signal line HCLK including the electrical contacts BP9 and LP9, Hot line communication is performed through the signal line HDAT formed of the electrical contacts BP10 and LP10, in which communication is performed at a cycle shorter than the command data communication (for example, at intervals of 1 millisecond).

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 hotline 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. A coefficient K _max is included. Here, the current position image plane movement coefficient K _cur is an image plane movement coefficient K corresponding to the current lens position (focal length) of the zoom lens 32 and the current lens position (shooting distance) of the focus lens 33. 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, thereby 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. 4, 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 “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. 7 is a timing chart showing an example of hotline communication. FIG. 7A is a diagram illustrating a state in which hotline communication is repeatedly performed at predetermined intervals Tn. Further, FIG. 7B 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 601 for generating lens position data. The generation process 601 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 generation process 601, the lens control unit 36 and the lens side second communication unit 382 output an L level signal to the signal line HANS (T 7). Then, when this signal is input to the electrical contact BP8, the camera control unit 21 and the camera-side second communication unit 292 output a clock signal 602 from the electrical contact BP9 to the signal line HCLK.

  The lens control unit 36 and the lens side second communication unit 382 output a lens position data signal 603 representing lens position data from the electrical contact LP10 to the signal line HDAT in synchronization with the clock signal 602. When the transmission of the lens position data signal 603 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, an operation example of the camera 1 according to the present embodiment will be described with reference to FIG. FIG. 7 is a flowchart showing the operation of the camera 1 according to this embodiment. The following operation is started when the camera 1 is turned on.

  First, in step S101, the camera body 2 performs communication for identifying the lens barrel 3. This is because communicable communication formats differ depending on the type of lens barrel. In step S102, the camera control unit 21 determines whether the lens barrel 3 is a lens corresponding to a predetermined first type communication format. As a result, when it is determined that the lens is compatible with the first type of communication format, the process proceeds to step S103. On the other hand, if the camera control unit 21 determines that the lens barrel 3 is a lens that does not support the predetermined first type communication format, the process proceeds to step S112. If the camera control unit 21 determines that the lens barrel 3 is a lens that supports a second type of communication format different from the first type of communication format, the camera control unit 21 may proceed to step S112. Further, when the camera control unit 21 determines that the lens barrel 3 is a lens compatible with the first type and the second type of communication format, the camera control unit 21 may proceed to step S103.

  Next, in step S103, it is determined whether or not the photographer has operated to turn on the live view shooting on / off switch provided in the operation unit 28. When the live view shooting is turned on, the mirror system 220 is turned on. Becomes the shooting position of the subject, and the luminous flux from the subject is guided to the image sensor 22.

In step S104, hotline communication is started between the camera body 2 and the lens barrel 3. In the hot line communication, as described above, when the lens control unit 36 receives the L level signal (request signal) output to the signal line HREQ by the camera control unit 21 and the second camera side communication unit 292, The lens information is transmitted to the camera control unit 21 and such lens information is repeatedly transmitted. The lens information includes, for example, each of 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 . Contains information. Hot line communication is repeated after step S104. For example, the hot line communication is repeatedly performed until the power switch is turned off. At this time, 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 are the current position image plane movement coefficient K _cur , the minimum image plane movement coefficient K _min , and the maximum. It is preferable to transmit in the order of the image plane movement coefficient _Kmax .

When the lens control unit 36 transmits lens information to the camera control unit 21, a table (see FIG. 4) showing a relationship between each lens position and the image plane movement coefficient K stored in the lens memory 37. Referring to the current position image plane movement coefficient K _cur corresponding to the current lens position of the zoom lens 32 and the current lens position of the focus lens 33, and the maximum image plane movement corresponding to the current lens position of the zoom lens 32. The coefficient K _max and the minimum image plane movement coefficient K _min are acquired, and the acquired current position image plane movement coefficient K _cur , maximum image plane movement coefficient K _max , and minimum image plane movement coefficient K _min are transmitted to the camera control unit 21. To do.

  In step S105, it is determined whether or not the photographer has performed a half-press operation of the release button (first switch SW1 is turned on) provided in the operation unit 28 or an AF activation operation, and these operations are performed. If so, the process proceeds to step S106 (in the following, the case where a half-press operation has been performed will be described in detail).

  Next, in step S106, the camera control unit 21 transmits a scan driving command (scan driving start instruction) to the lens control unit 36 in order to perform focus detection by the contrast detection method. The scan drive command (instruction of drive speed at the time of scan drive or instruction of drive position) to the lens control unit 36 may be given by the drive speed of the focus lens 33 or may be given by the image plane moving speed. Alternatively, it may be given as a target drive position.

In step S107, the camera control unit 21 performs a process of determining the scan drive speed V, which is the drive speed of the focus lens 33 in the scan operation, based on the minimum image plane movement coefficient K _min acquired in step S104. Is called. Here, the scan operation refers to the calculation of the focus evaluation value by the contrast detection method by the camera control unit 21 while the focus lens 33 is driven by the focus lens drive motor 331 at the scan drive speed V determined in step S107. Are performed simultaneously at predetermined intervals, whereby the detection of the in-focus position by the contrast detection method is executed at predetermined intervals.

  In this scanning operation, when detecting the in-focus position by the contrast detection method, the camera control unit 21 calculates a focus evaluation value at a predetermined sampling interval while driving the focus lens 33 to scan. A lens position at which the calculated focus evaluation value reaches a peak is detected as a focus position. Specifically, the camera control unit 21 scans the focus lens 33 to move the image plane of the optical system in the optical axis direction, thereby calculating a focus evaluation value on a different image plane, The lens position at which the evaluation value reaches a peak is detected as the focus position. On the other hand, however, if the moving speed of the image plane is made too fast, the interval between the image planes for calculating the focus evaluation value becomes too large, and the focus position may not be detected properly. . In particular, the image plane movement coefficient K indicating the amount of movement of the image plane with respect to the driving amount of the focus lens 33 changes according to the lens position of the focus lens 33 in the optical axis direction. Even when the focus lens 33 is driven, the moving speed of the image plane becomes too fast depending on the lens position of the focus lens 33. Therefore, the interval between the image planes for calculating the focus evaluation value becomes too large, and the in-focus position is set. It may become impossible to detect properly.

Therefore, in this embodiment, the camera control unit 21, based on the minimum image plane shift factor K _min acquired in step S104, and calculates the scan driving speed V at the time of performing the scan driving of the focus lens 33. The camera control unit 21 uses a minimum image plane movement coefficient K _min to scan at a driving speed at which the in-focus position can be appropriately detected by a contrast detection method and at a maximum driving speed. A drive speed V is calculated.

  In step S108, the scan operation is started at the scan drive speed V determined in step S107. Specifically, the camera control unit 21 sends a scan drive start command to the lens control unit 36, and the lens control unit 36 drives the focus lens drive motor 331 based on the command from the camera control unit 21 to focus. The lens 33 is scan-driven at the scan drive speed V determined in step S107. Then, the camera control unit 21 reads out the pixel output from the imaging pixels of the imaging element 22 at predetermined intervals while driving the focus lens 33 at the scan driving speed V, and calculates a focus evaluation value based on the readout. Thereby, the focus evaluation value at different focus lens positions is acquired, and the focus position is detected by the contrast detection method.

  Next, in step S109, the camera control unit 21 determines whether the peak value of the focus evaluation value has been detected (whether the in-focus position has been detected). When the peak value of the focus evaluation value cannot be detected, the process returns to step S108, and the operations of steps S108 and S109 are performed until the peak value of the focus evaluation value can be detected or until the focus lens 33 is driven to a predetermined driving end. Repeat. On the other hand, when the peak value of the focus evaluation value can be detected, the process proceeds to step S109.

  When the peak value of the focus evaluation value can be detected, the process proceeds to step S110, and in step S110, the camera control unit 21 instructs the lens control unit 36 to drive the focus to a position corresponding to the peak value of the focus evaluation value. Send. The lens control unit 36 performs drive control of the focus lens 33 in accordance with the received command.

  Next, the process proceeds to step S111. In step S111, the camera control unit 21 determines that the focus lens 33 has reached the position corresponding to the peak value of the focus evaluation value, and the photographer fully presses the shutter release button ( When the second switch SW2 is turned on, still image shooting control is performed. After the photographing control is completed, the process returns to step S104 again.

On the other hand, when it is determined in step S102 that the lens barrel 3 is a lens that does not support the predetermined first type communication format, the process proceeds to step S112, and the processes of steps S112 to S120 are executed. In steps S112 to S120, when the lens information is repeatedly transmitted by hot line communication between the camera body 2 and the lens barrel 3, as the lens information, the minimum image plane movement coefficient K _min , and When determining the point at which information that does not include the information on the maximum image plane movement coefficient K _max is transmitted (step S113) and the scan drive speed V that is the drive speed of the focus lens 33 in the scan operation. instead of the minimum image plane shift factor K _min or corrected minimum image plane shift factor K _{min_x,} that it uses the current position image plane shift factor K _cur included in the lens information other than (step S116) it includes a step S103~S111 described above Similar processing is executed.

As described above, in the present embodiment, the contrast using the minimum image plane movement coefficient K _min that is the minimum image plane movement coefficient among the image plane movement coefficients K stored in the lens memory 37 of the lens barrel 3. Since the scan drive speed V is calculated so that the in-focus position can be appropriately detected by the detection method and the maximum drive speed is obtained, the image plane movement coefficient K is a minimum value (for example, Even when the focus lens 33 is scan-driven to a position that is the same value as the minimum image plane movement coefficient K _min ), the focus evaluation value calculation interval (image plane interval for calculating the focus evaluation value) is used for focus detection. It can be a suitable size. As a result, according to the present embodiment, when the focus lens 33 is driven in the direction of the optical axis, the image plane movement coefficient K changes, and as a result, the image plane movement coefficient K becomes smaller ( For example, even when the minimum image plane movement coefficient K _min is reached, the focus position can be detected appropriately by the contrast detection method.

<< Second Embodiment >>
Next, a second embodiment of the present invention will be described. In the second embodiment, in the camera 1 shown in FIG. 1, among the image plane movement coefficients K stored in the lens memory 37 of the lens barrel 3, the minimum image plane movement coefficient K _min and the maximum image plane movement coefficient K _max are set. Except for the setting method being different, it has the same configuration as that of the first embodiment described above, operates in the same way, and produces the same effects.

In the present embodiment, the image plane movement coefficient K is set so that the image plane movement coefficient K when the focus lens 33 is driven in the vicinity of the closest soft limit position 460 becomes a minimum value. That is, the image plane movement coefficient K when the focus lens 33 is driven in the vicinity of the closest soft limit position 460 becomes a minimum value, compared with the case where the focus lens 33 is moved from the closest soft limit position 460 to the infinite soft limit position 450. Thus, the image plane movement coefficient K is set.
Similarly, the image plane movement coefficient K is set so that the image plane movement coefficient K when the focus lens 33 is driven in the vicinity of the infinite soft limit position 450 becomes the maximum value. That is, the image plane movement coefficient K when the focus lens 33 is driven closer to the infinite soft limit position 450 becomes the maximum value than when the focus lens 33 is moved from the closest soft limit position 460 to the infinite soft limit position 450. Thus, the image plane movement coefficient K is set.
That is, regarding the minimum image plane movement coefficient K _min , in the first embodiment described above, the image plane movement coefficient K when the focus lens 33 is driven in the vicinity of the close focus position 480 including the close focus position 480 is set. Although the minimum image plane movement coefficient K _min is set, in the second embodiment, the image plane movement coefficient K when the focus lens 33 is driven near the close soft limit position 460 including the close soft limit position 460 is set. The minimum image plane movement coefficient K _min is set.

Here, FIG. 9 is 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 used in the second embodiment. Show. That is, in the second embodiment, the image plane movement coefficient K in “D0”, which is a region closer to “D1” than the region indicated by “D1” including the closest focus position 480 shown in FIG. The surface movement coefficient K _min is set. In the present embodiment, among the lens positions of the focus lens 33, “D0” is a predetermined area corresponding to the closest soft limit position 460 shown in FIG. For example, it is a predetermined area in the vicinity of the closest soft limit position 460 shown in FIG. “D10” is a predetermined area corresponding to the infinite soft limit position 450 shown in FIG. For example, it is a predetermined area near the infinite soft limit position 450 shown in FIG. In FIG. 9, “K10”, “K20”, “K30”, “K40”, “K50”, “K60”, “K70”, “K80”, and “K90” shown in gray are zoomed. A minimum image plane movement coefficient K _min indicating a minimum value among the image plane movement coefficients K at each lens position (focal length) of the lens 32 is shown.

Similarly, regarding the maximum image plane movement coefficient K _max , in the first embodiment described above, the image plane movement coefficient K when the focus lens 33 is driven near the infinite focus position 470 including the infinite focus position 470. Is set to the maximum image plane movement coefficient K _max , but in the second embodiment, the image plane movement coefficient K when the focus lens 33 is driven in the vicinity of the infinite soft limit position 450 including the infinite soft limit position 450. _Is set to the maximum image plane movement coefficient K _max . That is, in the second embodiment, the image plane movement coefficient K in “D10”, which is an area at infinity further than the area indicated by “D9” including the infinite focus position 470 shown in FIG. This is set to the image plane movement coefficient _Kmax . In FIG. 9, hatched “K110”, “K210”, “K310”, “K410”, “K510”, “K610”, “K710”, “K810”, “K910” The maximum image plane movement coefficient K _max indicating the maximum value among the image plane movement coefficients K at the respective lens positions (focal lengths) of the zoom lens 32 is shown.

Alternatively, in the second embodiment, regarding the minimum image plane movement coefficient K _min , instead of the image plane movement coefficient K in the case where the focus lens 33 is driven in the vicinity of the close soft limit position 460 including the close soft limit position 460. In the vicinity of the mechanical end point 440 including the mechanical end point 440 in the close direction 420, the image plane movement coefficient K when the focus lens 33 is driven is set to the minimum image plane movement coefficient K _min , and the lens memory 37 is set. May be stored.

Furthermore, in the second embodiment, the maximum image plane movement coefficient K _max is replaced with the image plane movement coefficient K when the focus lens 33 is driven in the vicinity of the infinite soft limit position 450 including the infinite soft limit position 450. In the vicinity of the mechanical end point 430 including the mechanical end point 430 in the infinity direction 410, the image plane movement coefficient K when the focus lens 33 is driven is set to the minimum image plane movement coefficient K _max , and the lens memory 37 may be stored.

<< Third Embodiment >>
Next, a third embodiment of the present invention will be described. In the third embodiment, the camera 1 shown in FIG. 1 has the same configuration as that of the above-described first embodiment except that the camera 1 operates as described below.

That is, in the third embodiment, in the above-described first embodiment, in the flowchart shown in FIG. 8, in step S103, the minimum image plane movement coefficient K _min and the maximum image plane movement coefficient K _max transmitted as lens information are set. Instead, the corrected minimum image plane movement coefficient K _{min — X} and the corrected maximum image plane movement coefficient K _{max — X} are transmitted, and this is the same except for the difference from the first embodiment described above.

Here, the corrected minimum image plane movement coefficient K _{min — X} is an image plane movement coefficient obtained by correcting the minimum image plane movement coefficient K _min and having a smaller value than the minimum image plane movement coefficient K _min , The image plane movement coefficient calculated by multiplying the minimum image plane movement coefficient K _min by a constant α1 (for example, 0.9) smaller than 1. Similarly, the correction maximum image plane shift factor K _{max_x} is obtained by correcting the maximum image plane shift factor K _max, and a large image plane shift factor values than the maximum image plane shift factor K _max, e.g. The image plane movement coefficient calculated by multiplying the maximum image plane movement coefficient K _max by a constant α2 (for example, 1.1) larger than 1.

In the third embodiment, in the flowchart shown in FIG. 8, the minimum image plane movement is performed when the process of determining the scan drive speed V, which is the drive speed of the focus lens 33 in the scan operation, is executed in step S106. instead of the coefficient K _min, using a correction minimum image plane shift factor K _{min_x,} the determination of the scan driving speed V. In particular, in the third embodiment, a safety margin is set when determining the scan driving speed V by using a corrected minimum image plane movement coefficient K _{min — X} having a smaller value instead of the minimum image plane movement coefficient K _min. As a result, when focus detection is performed by the contrast detection method, the moving speed of the image plane becomes too fast, which makes it impossible to properly detect the in-focus position. Can be prevented more reliably.

As the corrected minimum image plane movement coefficient K _{min — X} and the corrected maximum image plane movement coefficient K _{max — X} , those calculated in advance may be stored in the lens memory 37 and used. The constants α1 and α2 when calculating the corrected minimum image plane movement coefficient K _{min — X} and the corrected maximum image plane movement coefficient K _{max — X} may be set as appropriate according to the imaging conditions and the like, and may be calculated for each process. In the third embodiment, as a method of obtaining the corrected minimum image plane movement coefficient K _{min — X} and the corrected maximum image plane movement coefficient K _{max — X} , the minimum image plane movement coefficient K _min and the maximum image plane movement coefficient K _max before correction are used. Although the method of multiplying the predetermined constants α1 and α2 is exemplified, the method is not particularly limited to such a method.

Furthermore, the minimum image in the third embodiment, the lens barrel 3 to the camera body 2, when transmitting the corrected minimum image plane shift factor K _{min_x} and correcting the maximum image plane shift factor K _{max_x} is not subjected to correction It can be set as the aspect which transmits by the system similar to the surface movement coefficient _Kmin and the maximum image surface movement coefficient _Kmax . In other words, in practice, the corrected minimum image plane movement coefficient K _{min — X} and the corrected maximum image plane movement coefficient K _{max — X} are transmitted, while the camera body 2 has the minimum image plane movement coefficient K _min and the correction not performed. It is possible to adopt a mode in which transmission is performed in such a manner as to be recognized as the maximum image plane movement coefficient K _max , whereby the processing in the camera body 2 can be simplified.

<< 4th Embodiment >>
Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, the camera 1 shown in FIG. 1 has the same configuration as that of the above-described first embodiment except that the camera 1 operates as described below.

  That is, in the fourth embodiment, in the flow chart shown in FIG. 7 in the first embodiment described above, when the in-focus position can be detected by the contrast detection method in step S109, the contrast detection method is changed in step S110. When performing focus driving based on the result, it is determined whether or not rattling driving is performed, and based on the determination, the drive format of the focus lens 33 when performing focus driving is different. This point is the same except that it differs from the first embodiment described above.

  In other words, the focus lens drive motor 331 for driving the focus lens 33 shown in FIG. 1 is usually composed of a mechanical drive transmission mechanism, and such a drive transmission mechanism is, for example, as shown in FIG. The first driving mechanism 500 and the second driving mechanism 600 are driven. When the first driving mechanism 500 is driven, the second driving mechanism 600 on the side of the focus lens 33 is driven accordingly. The focus lens 33 is configured to move to the near side or the infinity side. And in such a drive mechanism, the backlash amount G is normally provided from a viewpoint of the smooth operation | movement of the meshing part of a gearwheel. However, on the other hand, in the contrast detection method, due to the mechanism, as shown in FIGS. 11A and 11B, the focus lens 33 is once moved past the in-focus position by the scanning operation. It is necessary to reverse the driving direction and drive to the in-focus position. In this case, the lens position of the focus lens 33 is deviated from the in-focus position by the backlash amount G when the backlash driving is not performed as shown in FIG. For this reason, in order to remove the influence of such a backlash amount G, as shown in FIG. 11A, when the focus lens 33 is driven to focus, the focus lens 33 is passed once again after passing the focus position. Therefore, it becomes necessary to perform backlash driving that reverses the driving direction to drive the focusing position.

FIG. 11 shows the relationship between the focus lens position and the focus evaluation value and the relationship between the focus lens position and time when performing the focus drive based on the scan operation and the contrast detection method according to the present embodiment. FIG. Then, FIG. 11 (A) at time t _0, the lens position P0, after starting the scanning operation of the focus lens 33 toward the near side from the infinity side, at time t _1, the focus lens 33 is a lens position When the peak position (focus position) P2 of the focus evaluation value is detected at the time of moving to P1, the scan operation is stopped, and focus drive with backlash drive is performed, so that at time t ₂ The mode in which the focus lens 33 is driven to the in-focus position is shown. On the other hand, in FIG. 11B, similarly, after the scan operation is started at time t ₀ , the scan operation is stopped at time t ₁ , and focus drive is performed without backlash drive. A mode in which the focus lens 33 is driven to the in-focus position at time t ₃ is shown.

Below, the operation example in 4th Embodiment is demonstrated according to the flowchart shown in FIG. The following operation is executed when the in-focus position is detected by the contrast detection method in step S109 in the flowchart shown in FIG. That is, as shown in FIGS. 11A and 11B, the scanning operation is started from time t ₀ , and the focus evaluation value is obtained when the focus lens 33 is moved to the lens position P _{1 at} time t ₁ . peak position of (the focus position) when P2 is detected, is performed at the time of time t _1.

That is, when the in-focus position is detected by the contrast detection method, first, in step S201, the camera control unit 21 obtains the minimum image plane movement coefficient K _min at the current lens position of the zoom lens 32. The minimum image plane movement coefficient K _min is controlled by the lens via the lens transmission / reception unit 39 and the camera transmission / reception unit 21 by hot line communication performed between the camera control unit 21 and the lens control unit 36 described above. It can be obtained from the unit 36.

  Next, in step S202, the camera control unit 21 acquires information on the backlash amount G (see FIG. 10) of the drive transmission mechanism of the focus lens 33. Note that the play amount G of the drive transmission mechanism of the focus lens 33 can be obtained by, for example, storing it in advance in the lens memory 37 provided in the lens barrel 3 and referring to it. Specifically, the camera control unit 21 sends a transmission request for the play amount G of the drive transmission mechanism of the focus lens 33 to the lens control unit 36 via the camera transmission / reception unit 29 and the lens transmission / reception unit 38. Then, the lens control unit 36 can acquire the information on the backlash amount G of the drive transmission mechanism of the focus lens 33 stored in the lens memory 37 by transmitting the information. Alternatively, the backlash amount G of the drive transmission mechanism of the focus lens 33 stored in the lens memory 37 is added to the lens information transmitted / received by the hotline communication performed between the camera control unit 21 and the lens control unit 36 described above. It can also be set as the aspect which includes information.

Next, in step S203, the camera control unit 21 based on the acquired minimum image plane shift factor K _min, and amount of play information G of the drive transmission mechanism of the focus lens 33 acquired in step S202 described above in the step S201 described above Thus, the image plane movement amount I _G corresponding to the backlash amount _G is calculated. The image plane movement amount I _G corresponding to the backlash amount G is the amount of image plane movement when the focus lens is driven by the same amount as the backlash amount G. In this embodiment, the image plane movement amount I _G is calculated according to the following equation. To do.
Image plane movement amount I _G corresponding to the amount of play _G = Backlash amount G × Minimum image plane movement coefficient K _min

Next, in step S204, the camera control unit 21 performs a process of comparing the image plane movement amount I _G corresponding to the play amount G calculated in step S203 described above with a predetermined image plane movement amount I _P. result of the comparison, the image plane movement amount I _G corresponding to amount of play G, or less than a predetermined image plane movement amount I _P, i.e., "the image plane movement amount corresponding to the backlash amount G I _G" ≦ " predetermined image plane movement amount I _P "a determination is made whether or not satisfied. The predetermined image plane movement amount _IP is set corresponding to the depth of focus of the optical system, and is usually an image plane movement amount corresponding to the depth of focus. In addition, since the predetermined image plane movement amount IP is set to the depth of focus of the optical system, the predetermined image plane movement amount _IP is appropriately set according to the F value, the cell size of the image sensor 22, and the format of the image to be captured. It can be. That is, as the F value is large, it is possible to set a large predetermined image plane movement amount I _P. Alternatively, the larger the cell size of the imaging device 22, or, as the image format is small, it is possible to set a large predetermined image plane movement amount I _P. Then, the image plane movement amount I _G corresponding to backlash amount G is equal to or less than the predetermined image plane movement amount I _P, the process proceeds to step S205. On the other hand, the image plane movement amount I _G corresponding to backlash amount G is greater than the predetermined image plane movement amount I _P, the process proceeds to step S206.

In step S205, in step S204 described above, the image plane movement amount I _G corresponding to backlash amount G is, because it was determined to be less than or equal to a predetermined image plane movement amount I _P, in this case, not the play reduction drive Even in this case, it is determined that the lens position of the focus lens 33 after being driven can be within the depth of focus of the optical system, it is determined that no backlash driving is performed at the time of in-focus driving, and based on this determination Focus drive is performed without driving. That is, when performing the focus drive, it is determined that the focus lens 33 is driven directly to the focus position, and based on this determination, as shown in FIG. Do the focus drive.

On the other hand, in step S206, in step S204 described above, the image plane movement amount I _G corresponding to backlash amount G is, since it is determined greater than the predetermined image plane movement amount I _P, in this case, the play elimination drive Otherwise, it is determined that the lens position of the focus lens 33 after being driven cannot be within the focal depth of the optical system, and it is determined that the backlash driving is performed at the time of in-focus driving. Based on this determination, the backlash driving is performed. In-focus drive is performed. That is, when driving the focus lens 33 and performing focus driving, it is determined that the focus position is once passed and then reversely driven again to drive to the focus position. Based on this, as shown in FIG. 10 (A), focusing driving with backlash driving is performed.

In the fourth embodiment, as described above, the image plane movement amount I _G corresponding to the play amount G is based on the minimum image plane movement coefficient K _min and the information on the play amount G of the drive transmission mechanism of the focus lens 33. And determining whether or not the image plane movement amount I _G corresponding to the calculated backlash amount G is equal to or less than a predetermined image plane movement amount I _P corresponding to the focal depth of the optical system. When the driving is performed, the backlash control for determining whether or not the backlash driving is executed is executed. As a result of the determination, the image plane movement amount I _G corresponding to backlash amount G is not greater than the predetermined image plane movement amount I _P corresponding to the depth of focus of the optical system, the lens position of the focus lens 33 after driving When the optical system can be within the focal depth of the optical system, the backlash driving is not performed, while the image plane movement amount I _G corresponding to the backlash _G is a predetermined image plane corresponding to the focal depth of the optical system. greater than the movement amount I _P, without play reduction drive, the lens position of the focus lens 33 after driving, if it can not be within the depth of focus of the optical system is configured to perform the play reduction drive. Therefore, according to the present embodiment, when the backlash driving is not necessary, it is possible to reduce the time required for the focusing drive by not performing the backlash driving. Can be shortened. On the other hand, when the backlash driving is necessary, the focusing accuracy can be improved by performing the backlash driving.

Particularly, in the fourth embodiment, using the minimum image plane shift factor K _min, to calculate the image plane movement amount I _G corresponding to backlash amount G of the drive transmission mechanism of the focus lens 33, which, in the optical system by comparing with a predetermined image plane movement amount I _P corresponding to the focal depth, it is possible to properly determine the necessity of play reduction drive during focusing.

  Note that in the backlash control according to the above-described fourth embodiment, the camera control unit 21 may determine whether or not backlash is necessary according to the focal length, the aperture, and the subject distance. Further, the camera control unit 21 may change the driving amount of the backlash according to the focal length, the aperture, and the subject distance. For example, when the aperture is narrowed below a predetermined value (when the F value is large), the backlash is not necessary compared to when the aperture is not narrowed below the predetermined value (when the F value is small). Control may be made so as to reduce the driving amount of judgment or backlashing. Furthermore, for example, the wide side may be controlled so as to determine that the backlash is unnecessary or the driving amount of backlash may be reduced compared to the tele side.

<< 5th Embodiment >>
Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, the camera 1 shown in FIG. 1 has the same configuration as that of the above-described first embodiment except that the camera 1 operates as described below.

  That is, in the fifth embodiment, a clip operation (silent control) described below is performed. In the fifth embodiment, in the search control using the contrast detection method, control is performed so that the moving speed of the image plane of the focus lens 33 is constant, while in the search control using the contrast detection method, the focus lens 33 is driven. A clip operation for suppressing sound is performed. Here, the clip operation performed in the fifth embodiment is an operation of clipping the speed of the focus lens 33 so that the speed of the focus lens 33 does not become less than the moving speed of the lower limit lens when the speed of the focus lens 33 is slowed down and noise reduction is hindered. is there.

  In the fifth embodiment, as will be described later, the camera control unit 21 of the camera body 2 uses a predetermined coefficient (Kc) to set a predetermined silent lower limit lens moving speed V0b and a focus lens driving speed V1a. By comparing, it is determined 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 V1a 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 the flowchart shown in FIG. Here, FIG. 13 is a flowchart showing the clip operation (silent control) according to the fifth embodiment.

  In step S301, 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 S302, 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 S303, the lens control unit 36 compares the silent lower limit lens moving speed V0b acquired in step S301 with the drive instruction speed of the focus lens 33 acquired in step S302. 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 S304. 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 S305. move on.

  In step S304, 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 V1a of the focus lens 33 with the silent lower limit lens moving speed V0b.

  On the other hand, in step S305, 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 (or the driving sound is very small), the lens control unit 36 drives the focus lens 33 transmitted from the camera body 2. Drive at the indicated speed.

  Here, FIG. 14 is a graph for explaining the relationship between the lens driving speed V1a of the focus lens 33 and the silent lower limit lens moving speed V0b. The vertical axis represents the lens driving speed, and the horizontal axis represents the image plane movement coefficient K. It is a graph. As shown by the horizontal axis in FIG. 14, the image plane movement coefficient K changes according to the lens position of the focus lens 33. In the example shown in FIG. Therefore, the image plane movement coefficient K tends to increase toward the infinity side. On the other hand, in the present embodiment, when the focus lens 33 is driven during the focus detection operation, the focus lens 33 is driven at a speed at which the moving speed of the image plane is constant. As shown, the actual driving speed V1a of the focus lens 33 changes according to the lens position of the focus lens 33. That is, in the example shown in FIG. 14, when the focus lens 33 is driven so that the moving speed of the image plane becomes a constant speed, the lens moving speed V1a of the focus lens 33 becomes slower as it approaches the infinite side. It gets faster.

  On the other hand, when the focus lens 33 is driven as shown in FIG. 14, the image plane moving speed in such a case is constant as shown in FIG. FIG. 16 is a graph for explaining the relationship between the image plane moving speed V1a driven by the focus lens 33 and the silent lower limit image plane moving speed V0b_max. The vertical axis represents the image plane moving speed, and the horizontal axis represents the image. It is a graph made into the surface movement coefficient K. In FIGS. 14 and 16, the actual driving speed of the focus lens 33 and the image plane moving speed by driving the focus lens 33 are both represented by V1a. Therefore, V1a is variable (not parallel to the horizontal axis) when the vertical axis of the graph is the actual driving speed of the focus lens 33 as shown in FIG. 14, and the vertical axis of the graph is shown in FIG. When the axis is the image plane moving speed, the value is constant (parallel to the horizontal axis).

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 driving speed V1a of the focus lens 33 is obtained as in the example shown in FIG. However, there are cases where the lower limit lens moving speed V0b is less than the silent minimum. For example, at the position of the focus lens 33 where the minimum image plane movement coefficient K _min is obtained (the minimum image plane movement coefficient K _min = 100 in FIG. 14), the lens movement speed V1a 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 V1a 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 V1a of the focus lens 33 with the silent lower limit lens moving speed V0b as shown in FIG. 14 (from the silent lower limit lens moving speed V0b). (Step S304), and thus the driving sound of the focus lens 33 can be suppressed.

  Next, with reference to FIG. 15, the clip operation control process for determining whether to permit or prohibit the clip operation shown in FIG. FIG. 15 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 S401, 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 S402, the camera control unit 21 calculates the silent lower limit image plane moving speed V0b_max. The quiet lower image plane movement velocity V0b_max, at the position of the focus lens 33 to minimize image plane shift factor K _min is obtained, definitive focus lens 33, when driven by the above-mentioned silent lower lens moving speed V0b, image plane Is the moving speed. Hereinafter, the silent lower limit image plane moving speed V0b_max will be described in detail.

  First, as shown in FIG. 14, whether or not the driving sound is generated by driving the focus lens 33 is determined by the actual driving speed of the focus lens 33. Therefore, as shown in FIG. The lower limit lens moving speed V0b is a constant speed when expressed as a lens driving speed. On the other hand, when the silent lower limit lens moving speed V0b is expressed by the image plane moving speed, the image plane moving coefficient K changes according to the lens position of the focus lens 33 as described above. As shown in FIG. 14 and 16, the silent lower limit lens moving speed (the lower limit value of the actual driving speed of the focus lens 33) and the image plane moving speed when the focus lens 33 is driven at the silent lower limit lens moving speed. Are both represented by V0b. Therefore, V0b is a constant value (parallel to the horizontal axis) when the vertical axis of the graph is the actual driving speed of the focus lens 33 as shown in FIG. 14, and the vertical axis of the graph is shown in FIG. When the axis is the image plane moving speed, it is variable (not parallel to the horizontal axis).

In the present embodiment, a quiet limit image plane movement velocity V0b_max, the focus lens when the moving speed of the image plane was driven focus lens 33 to be constant, the minimum image plane shift factor K _min is obtained 33 (In the example shown in FIG. 16, the image plane movement coefficient K = 100), the moving speed of the focus lens 33 is set to the image plane moving speed at which the silent lower limit lens moving speed V0b is obtained. That is, in the present embodiment, when the focus lens 33 is driven at the silent lower limit lens moving speed, the maximum image plane moving speed (in the example shown in FIG. 16, the image plane moving at the image plane moving coefficient K = 100). Speed) is set as the silent lower limit image plane moving speed V0b_max.

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 V0b_max. For example, in the example shown in FIG. 16, 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 V0b_max.

Specifically, the camera control unit 21, as shown in the following formula, quiet lower lens moving speed V0b (unit: pulse / s) minimum image plane shift factor and K _min (unit: pulse / mm) on the basis of the The silent lower limit image plane moving speed V0b_max (unit: mm / second) is calculated.
(Actual driving speed of the focus lens) V0b / Min image plane shift factor K _min silent lower image plane movement velocity V0b_max = silent lower lens moving speed

Thus, in the present embodiment, by using the minimum image plane shift factor K _min, by calculating the quiet lower image plane movement velocity V0b_max, at the timing of starting the focus detection and video recording by AF-F, quiet limit The image plane moving speed V0b_max can be calculated. For example, in the example shown in FIG. 16, when focus detection or moving image shooting by AF-F is started at timing t1 ′, the lens of the focus lens 33 whose image plane movement coefficient K is “100” at timing t1 ′. The image plane moving speed at the position can be calculated as the silent lower limit image plane moving speed V0b_max.

Next, in step S403, the camera control unit 21 compares the image plane moving speed V1a for focus detection acquired in step S401 with the silent lower limit image plane moving speed V0b_max calculated in step S402. Specifically, the camera control unit 21 determines whether the image plane moving speed V1a (unit: mm / sec) for focus detection and the silent lower limit image plane moving speed V0b_max (unit: mm / sec) satisfy the following expression: Judge whether or not.
(Focus detection image plane moving speed V1a × Kc)> Silent lower limit image plane moving speed V0b_max
In the above formula, the coefficient Kc is a value of 1 or more (Kc ≧ 1), and details thereof will be described later.

  If the above equation is satisfied, the process proceeds to step S404, and the clip operation shown in FIG. That is, in order to suppress the drive sound of the focus lens 33, the drive speed V1a of the focus lens 33 is limited to the silent lower limit lens moving speed V0b as shown in FIG. 14 (the drive speed V1a 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 is not satisfied, the process proceeds to step S405, and the clip operation shown in FIG. 13 is prohibited. That is, the focusing speed is not limited by the silent lower limit lens moving speed V0b (the driving speed V1a of the focusing lens 33 is allowed to be lower than the silent lower limit lens moving speed V0b). The focus lens 33 is driven so that the image plane moving speed V1a can be detected appropriately.

  Here, as shown in FIG. 14, if the clip operation is permitted and the driving speed of the focus lens 33 is limited by the silent lower limit lens moving speed V0b, the image plane is at a lens position where the image plane moving coefficient K is small. As a result, the moving speed of the image plane becomes faster than the moving speed of the image plane that can appropriately detect the in-focus position, and appropriate focusing accuracy may not be obtained. On the other hand, when the clipping lens is prohibited and the focus lens 33 is driven so that the moving speed of the image plane becomes an image plane moving speed at which the in-focus position can be appropriately detected, as shown in FIG. The driving speed V1a 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 V0b_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 may become.

  On the other hand, in this embodiment, even when the coefficient Kc in the above equation satisfies the above equation even when the focus lens 33 is driven at the silent lower limit lens moving speed V0b, a certain focus detection accuracy can be ensured. It is stored as a value of 1 or more. Thereby, as shown in FIG. 16, the camera control unit 21 maintains a constant focus when the above expression is satisfied even when the image plane moving speed V1a for focus detection is less than the silent lower limit image plane moving speed V0b_max. It is determined that the 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 permitted 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 (Kc ≧ 1) at the time of focus detection is equal to or lower than the silent lower limit image plane moving speed V0b_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 the focus detection accuracy may not be ensured. Therefore, when the above formula is not satisfied, the camera control unit 21 gives priority to 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 camera control unit 21 may increase the coefficient Kc of the above formula as the aperture value increases. it can.

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

  Next, with reference to FIG. 17 and FIG. 18, the control of the clip operation will be described in more detail. FIG. 17 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, and FIG. 18 illustrates the relationship between the actual lens driving speed V1a of the focus lens 33 and the clipping operation. It is a figure for doing.

  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. 17 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. 17 is the maximum moving speed among the moving speeds of the image plane that can appropriately detect the focus state, and the image plane satisfying the relationship of the above formula. It is the moving speed. The image plane moving speed V1a_2 at the time of focus detection is an image plane moving speed that is slower than V1a_1, but is an image plane moving speed that satisfies the relationship of the above formula 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.

  As described above, in the example shown in FIG. 17, 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. The 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. 13 is prohibited because the relationship of the above equation is not satisfied.

  This point will be specifically described with reference to FIG. FIG. 18 is a diagram in which the vertical axis of the graph shown in FIG. 17 is changed from the image plane moving speed to the lens driving speed. As described above, since the lens driving speed V1a_1 of the focus lens 33 satisfies the relationship of the above formula (3), the clipping operation is permitted. However, as shown in FIG. 18, even at the lens position where the minimum image plane movement coefficient (K = 100) is obtained, the lens drive speed V1a_1 is not less than the silent lower limit lens movement speed V0b. No action is taken.

  Further, since the lens driving speed V1a_2 of the focus lens 33 also satisfies the relationship of the above formula at the timing t1 ′ that is the focus detection start timing, the clipping operation is permitted. In the example shown in FIG. 18, when the focus lens 33 is driven at the lens driving speed V1a_2, the lens driving speed V1a_2 is less than the silent lower limit lens moving speed V0b at the lens position where the image plane movement coefficient K is K1. , The lens driving speed V1a_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 clipping operation is performed at the lens position where the lens driving speed V1a_2 of the focus lens 33 is less than the silent lower limit lens moving speed V0b, whereby the moving speed V1a_2 of the image plane at the time of focus detection is The focus evaluation value search control is performed at a moving speed of the image plane different from the moving speed (search speed). That is, as shown in FIG. 17, at the lens position where the image plane movement coefficient is smaller than K1, the image plane movement speed V1a_2 at the time of focus detection is different from the constant speed so far.

  Further, since the lens drive speed V1a_3 of the focus lens 33 does not satisfy the relationship of the above formula, the clip operation is prohibited. Therefore, in the example shown in FIG. 18, when the focus lens 33 is driven at the lens driving speed V1a_3, the lens driving speed V1a_3 is less than the silent lower limit lens moving speed V0b at the lens position where the image plane movement coefficient K is K2. However, at the lens position where an image plane movement coefficient K smaller than K2 is obtained, the clipping operation is not performed, and the driving speed V1a_3 of the focus lens 33 is less than the silent lower limit lens moving speed V0b in order to appropriately detect the focus state. In this case, the clip operation is not performed.

  As described above, in the fifth 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 V0b_max. Then, the calculated silent lower limit image plane moving speed V0b_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 V0b_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 clip operation shown in FIG. 13 is permitted. 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 image plane moving speed V1a × Kc (where Kc ≧ 1) at the time of focus detection is equal to or lower than the silent lower limit image plane moving speed V0b_max, the driving speed V1a 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. 13 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 V0b_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 V0b_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.

  In the above-described embodiment, the configuration in which the clip operation control process illustrated in FIG. 13 is executed in the camera body 2 is illustrated. 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 illustrated in the above formula, the configuration in which 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) is exemplified. However, the present invention is not limited to this configuration, and for example, a configuration for calculation as shown in the following formula may be adopted.
Image plane movement coefficient K = (Movement amount of image plane / drive amount of focus lens 33)
In this case, the camera control unit 21 can calculate the silent lower limit image plane moving speed V0b_max as follows. That is, as shown in the following equation, the camera control unit 21 includes the silent lower limit lens moving speed V0b (unit: pulses / second) and the image plane movement coefficient K at each lens position (focal length) of the zoom lens 32. The silent lower limit image plane moving speed V0b_max (unit: mm / second) can be calculated based on the maximum image plane movement coefficient K _max (unit: pulse / mm) indicating the maximum value.
Silent lower image plane movement velocity V0b_max = silent lower lens moving speed V0b / maximum image plane shift factor K _max

  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.

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 the suppression of the driving sound of the focus lens 33, and the clip operation shown in FIG. 13 may always be 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 / focus lens 33 drive amount) is defined, the maximum image plane movement coefficient K _max is used to perform a clip operation or the like in the above-described embodiment. Can be controlled.

<< 6th Embodiment >>
Next, a sixth embodiment of the present invention will be described. The sixth embodiment has the same configuration as that of the first embodiment described above except that the following points are different. FIG. 19 is 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 used in the sixth embodiment. In other words, in the sixth embodiment, “X1” and “X2” regions, which are regions closer to the region than “D0” including the closest soft limit position 460 illustrated in FIG. 9, are provided. . Further, areas “X3” and “X4” which are areas closer to the area than “D10” including the infinite soft limit position 450 are provided.

  The “X1” and “X2” areas are areas closer to the closest soft limit position, for example, positions corresponding to the mechanical end point 440 in the close direction 420, positions between the close soft limit position and the end point 440, etc. It is. The “X3” and “X4” areas are infinitely far from the infinite soft limit position, for example, positions corresponding to mechanical end points 430 in the infinite distance direction 410, positions between the infinite soft limit positions and the end points 430. Etc.

  In this embodiment, the values of the image plane movement coefficients “α11”, “α21”,... “Α91” in the “X1” region are the image plane movement coefficients “K10”, “ K20 ”,... Smaller than the value of“ K90 ”. Similarly, the values of the image plane movement coefficients “α12”, “α22”,... “Α92” in the “X2” area are the image plane movement coefficients “K10”, “K20”,. It is smaller than the value of “K90”. In addition, the values of the image plane movement coefficients “α13”, “α23”,... “Α93” in the “X3” area are the image plane movement coefficients “K110”, “K210”,. It is larger than the value of “K910”. The values of the image plane movement coefficients “α14”, “α24”,... “Α94” in the “X4” area are the image plane movement coefficients “K110”, “K210”,... “K910” in the “D10” area. Greater than the value of.

However, on the other hand, in the present embodiment, the image plane movement coefficient K (“K10”, “K20”... “K90”) at “D0” is set to the minimum image plane movement coefficient K _min and “D10”. The image plane movement coefficient K (“K110”, “K210”... “K910”) is set to the maximum image plane movement coefficient K _max . In particular, the “X1”, “X2”, “X3”, and “X4” regions are regions where the focus lens 33 is not driven or need not be driven due to aberrations, mechanical mechanisms, and the like. is there. Therefore, the image plane movement coefficients “α11”, “α21”,... “Α94” corresponding to the “X1”, “X2”, “X3”, and “X4” regions are set to the minimum image plane movement coefficient K _min and the maximum. This is because even if the image plane movement coefficient K _max is set, it does not contribute to appropriate autofocus control (for example, focus lens speed control, silence control, backlash control, etc.).

In this embodiment, the image plane movement coefficient in the “D0” area corresponding to the closest soft limit position 460 is set to the minimum image plane movement coefficient K _min , and the image in the “D10” area corresponding to the infinite soft limit position 450 is set. Although the plane movement coefficient is set to the maximum image plane movement coefficient _Kmax , the present invention is not limited to this.

For example, the lens memory 37 has image plane movement coefficients corresponding to the regions “X1” and “X2” closer to the closest soft limit position and the regions “X3” and “X4” closer to the infinite soft limit position. Is stored in the contrast AF search range (scan range), the smallest image plane movement coefficient among the image plane movement coefficients corresponding to the position of the focus lens included in the search range is set as the minimum image plane movement coefficient _Kmin. The largest image plane movement coefficient among the image plane movement coefficients corresponding to the position of the focus lens included in the search range of contrast AF may be set as the maximum image plane movement coefficient K _max . Further, the image plane movement coefficient corresponding to the closest focus position 480 is set to the minimum image plane movement coefficient K _min , and the image plane movement coefficient corresponding to the infinite focus position 470 is set to the maximum image plane movement coefficient K _max. Also good.

  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. Moreover, each embodiment mentioned above can also be used in combination as appropriate.

  Furthermore, the camera 1 of the above-described embodiment is not particularly limited. For example, as shown in FIG. 20, the present invention may be applied to a lens-interchangeable mirrorless camera 1a. In the example shown in FIG. 20, 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)

An interchangeable lens attached to the camera body,
An optical system including a focusing lens;
A drive unit for driving the focus adjustment lens in the optical axis direction of the optical system;
A first value at the lens position of the focus adjustment lens, which changes depending on the position of the focus adjustment lens and corresponds to the amount of movement of the image plane relative to the amount of movement of the focus adjustment lens;
A second value that is a value in the vicinity of the image plane movement coefficient that maximizes the amount of movement of the image plane relative to the amount of movement of the focus adjustment lens within the drive range of the focus adjustment lens by the drive unit, A transmission unit for transmitting to the body ,
The data amount of the image plane movement coefficient that maximizes the amount of movement of the image plane relative to the amount of movement of the focus adjustment lens is equal to the data amount of the second value transmitted to the camera body by the transmission unit. interchangeable lens. The interchangeable lens according to claim 1,
A zoom optical system for changing a focal length of the interchangeable lens;
An interchangeable lens in which the image plane movement coefficient that maximizes the amount of movement of the image plane relative to the amount of movement of the focusing lens changes as the lens position of the zoom optical system changes. The interchangeable lens according to claim 1 or 2,
The interchangeable lens, wherein the image plane movement coefficient is a coefficient corresponding to TI / TL, which is a ratio of an image plane movement amount TI to a movement amount TL of the focus adjustment lens. 4. The interchangeable lens according to claim 1, wherein the second value is smaller than an image plane movement coefficient that maximizes an image plane movement amount relative to a movement amount of the focus adjustment lens. 5. Or an interchangeable lens that is a great value.

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