JP2020170180A - Interchangeable lens, camera main body and camera - Google Patents

Abstract

To provide an interchangeable lens that transmits necessary information to a camera main body, to provide a camera main body that implements processing using the information from the interchangeable lens, and to provide a camera that includes such the camera main body and interchangeable lens.SOLUTION: An interchangeable lens is provided that has: a movable focusing optical system; and a communication unit that a first coefficient serving as an amount of movement of the focusing optical system with respect to an amount of movement of an image plane when the focusing optical system is present at a current position, and a second coefficient equal to or less than the first coefficient to the camera main body. The first coefficient and the second coefficient equal to or less than the first coefficient are transmitted to the camera main body from a lens barrel, which in turn allows the camera main body to implement accurate processing.SELECTED DRAWING: Figure 2

Description

The present invention relates to an interchangeable lens, a camera body and a camera.

A single-lens reflex digital camera consists of a camera body and an interchangeable lens (lens barrel).

JP-A-2010-139666

It is an object of the present invention to provide an interchangeable lens capable of suitably driving a focal optical system, a camera body to which an interchangeable lens can be attached, and a camera including the interchangeable lens and the camera body.

According to one aspect of the present invention, an interchangeable lens that can be attached to a camera body, a focal optical system that can move in the optical axis direction, and a first image that changes depending on the position of the focal optical system on the optical axis. Provided is an interchangeable lens including a transmission unit that transmits a surface movement coefficient and a second image plane movement coefficient equal to or lower than the first image plane movement coefficient to the camera body.

According to another aspect of the present invention, a movable focal optical system, a first coefficient which is a moving amount of the focal optical system with respect to a driving amount of an image plane when the focal optical system is in the current position, and An interchangeable lens having a communication unit that transmits a second coefficient equal to or lower than the first coefficient to the camera body is provided.

The perspective view which shows the single-lens reflex digital camera 1. The main part block diagram which shows the single-lens reflex digital camera 1. A table showing the relationship between the lens positions of the zoom lens 32 and the focus lens 33 and the image plane movement coefficient K. The schematic diagram which shows the detail of the connection part 202, 302. A timing chart showing an example of command data communication. A timing chart showing an example of hotline communication. The flowchart which shows the operation of the camera 1 which concerns on this embodiment. A sequence diagram showing an example of high-speed search judgment processing. The flowchart which shows the operation of the camera 1 when high-speed search is prohibited. The figure explaining the operation of the camera 1 when high-speed search is prohibited. The flowchart which shows the operation of the camera 1 when high-speed search is permitted. The figure explaining the operation of the camera 1 when high-speed search is permitted. The figure which shows an example of the relationship between the distance between the previous focusing position and the initial lens position, and the 2nd coefficient K2. The figure which shows an example of the relationship between the time required to search the entire search range and the 2nd coefficient K2. A sequence diagram showing an example of abnormality determination processing. Sequence diagram showing another example of abnormality determination processing The figure which shows an example of a drive transmission mechanism. The figure which shows the relationship between the position of a focus lens 33, a focus evaluation value and time. The sequence diagram which shows an example of the backlash packing judgment processing. The figure which shows typically the relationship between the magnitude of the 2nd coefficient K2, the focusing accuracy and the focusing speed. A sequence diagram showing an example of clip operation determination processing. The flowchart which shows an example of the processing operation of the lens barrel 3 when the clip operation is permitted. The figure which shows typically the relationship between the magnitude of the 2nd coefficient K2, quietness and focusing accuracy. The drive range of the focus lens 33. A table showing the relationship between the lens position of the zoom lens 32 and the lens position of the focus lens 33 and the image plane movement coefficient K. The figure which shows the relationship between the drive range of a focus lens 33 and the position of a focus lens 33. The figure which shows an example of the driveable range.

(First Embodiment)
Hereinafter, embodiments will be specifically described with reference to the drawings.

FIG. 1 is a perspective view showing a single-lens reflex digital camera 1 (hereinafter, simply referred to as a camera 1). Further, FIG. 2 is a configuration diagram of a main part showing the camera 1. The camera 1 is composed of a camera body 2 and a lens barrel 3, and the camera body 2 and the lens barrel 3 are detachably connected to each other.

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 has a built-in photographing optical system including lenses 31, 32, 33, 34 and an aperture 35.

The lens 33 is a focus lens (an example of a focal optical system), and the focal state distance of the photographing optical system can be adjusted by moving in the optical axis L1 direction. The focus lens 33 is movably provided along the optical axis L1 of the lens barrel 3, and its position is adjusted by the focus lens drive 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 response to 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 larger the number of pulses per unit time, the faster the drive speed of the focus lens 33.

In the present embodiment, the camera control unit 21 of the camera body 2 transmits the drive instruction speed (unit: pulse / second) of the focus lens 33 to the lens barrel 3. Then, the lens control unit 36 outputs a pulse signal corresponding to the drive instruction speed (unit: pulse / second) transmitted from the camera body 2 to the focus lens drive motor 331. As a result, the focus lens drive motor 331 drives the focus lens 33 at the drive instruction speed (unit: pulse / second) transmitted from the camera control unit 21. The above is also simply referred to as "the camera control unit 21 drives the focus lens 33".

The lens 32 is a zoom lens (an example of a variable magnification optical system), and the focal length of the photographing optical system can be adjusted by moving in the optical axis L1 direction. Similar to the focus lens 33 described above, the position of the zoom lens 32 is adjusted by the zoom lens drive motor 321 while the position is detected by the zoom lens encoder 322. The position of the zoom lens 32 is adjusted by operating the zoom button provided on the operation unit 28 of the camera body 2 or by operating the zoom ring (not shown) provided on the lens barrel 3. ..

The aperture 35 is configured so that the aperture diameter centered on the optical axis L1 can be adjusted in order to limit the amount of light of the luminous flux passing through the photographing optical system and reaching the image sensor 22 of the camera body 2 and to adjust the amount of blurring. Has been done. The adjustment of the aperture diameter by the aperture 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 on the camera body 2. The aperture diameter of the aperture 35 is detected by an aperture aperture sensor (not shown), and the lens control unit 36 recognizes the current aperture diameter.

The lens memory 37 stores the image plane movement coefficient K and the like. 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 driving amount of the focus lens 33 with respect to the moving amount of the image plane. The image plane movement coefficient is defined by, for example, the following equation (1), and the smaller the image plane movement coefficient K, the larger the amount of movement of the image plane accompanying the driving of the focus lens 33.

Image plane movement coefficient K = (Drive amount of focus lens 33 / Movement amount of image plane) ... (1)
In the camera 1, even when the drive amount of the focus lens 33 is the same, the amount of movement of the image plane differs depending on the lens position of the focus lens 33. Similarly, even if the drive amount of the focus lens 33 is the same, the amount of movement of the image plane differs depending on the lens position of the zoom lens 32.

That is, the image plane movement coefficient K changes according to the lens position in the optical axis direction of the focus lens 33 and the zoom lens 32, and in the present embodiment, the lens memory 37 is the lens position and zoom of the focus lens 33. The image plane movement coefficient K is stored for each lens position of the lens 32.

The image plane movement coefficient K may be defined as the image plane movement coefficient K = (image plane movement amount / drive amount of the focus lens 33). In this case, the larger the image plane movement coefficient K, the larger the amount of movement of the image plane that accompanies the driving of the focus lens 33. However, in the following, it is assumed that the image plane movement coefficient K is defined by the above equation (1).

Here, FIG. 3 shows a table showing the relationship between the lens position (focal length) of the zoom lens 32 and the lens position (shooting distance) of the focus lens 33 and the image plane movement coefficient K. In the table shown in FIG. 3, the drive region of the zoom lens 32 is divided into nine regions "f1" to "f9" in order from the wide end to the tele end, and the drive region of the focus lens 33 is brought close to each other. The image plane movement coefficient K corresponding to each lens position is stored in nine regions "D1" to "D9" in order from the end to the infinity end. For example, when the lens position (focal length) of the zoom lens 32 is at "f1" and the lens position (shooting distance) of the focus lens 33 is at "D1", the image plane movement coefficient K is "K11". The table shown in FIG. 3 illustrates an embodiment in which the drive region of each lens is divided into nine regions, but the number thereof is not particularly limited and can be set arbitrarily. In the present embodiment, the position of the focus lens 33 corresponding to the minimum image plane movement coefficient K _min has been described using an example in which the position of the focus lens 33 corresponding to the maximum image plane movement coefficient K _max is closer to the position of the focus lens 33. It is not limited to. For example, the position of the focus lens 33 corresponding to the minimum image plane movement coefficient K _min may be closer to infinity than the position of the focus lens 33 corresponding to the maximum image plane movement coefficient K _max . Further, for example, the image plane movement coefficient may be smaller as the position of the focus lens 33 is closer, or the image plane movement coefficient may be larger as the position of the focus lens 33 is closer, which is the closest. A position other than the position of the focus lens 33 on the side and the position of the focus lens 33 on the farthest infinity side may have a minimum value of the image plane movement coefficient or a maximum value of the image plane movement coefficient.
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. 3, "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 ,
The maximum value "K19" = "900" is the maximum image plane movement coefficient K _max .
When the zoom lens 32 is movable, 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 usually a constant value (fixed value) even if the current lens position of the focus lens 33 changes as long as the current lens position of the zoom lens 32 does not change. That is, the minimum image plane movement coefficient K _min is usually a fixed value (constant value) 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. It is a value that does not.

For example, in FIG. 3, “K11”, “K21”, “K31”, “K41”, “K52”, “K62”, “K72”, “K82”, and “K91” shown in gray are zoom lenses 32. Of the image plane movement coefficients K at each lens position (focal length) of the above, the minimum image plane movement coefficient K _min indicating the minimum value. That is, the lens position (focal length) of the zoom lens 32 is ".
In the case of "f1", among "D1" to "D9", "K11", which is the image plane movement coefficient K when the lens position (shooting distance) of the focus lens 33 is in "D1", is the smallest. The minimum image plane movement coefficient K _min indicating the value is obtained. Therefore, "K11", which is the image plane movement coefficient K when the lens position (shooting distance) of the focus lens 33 is at "D1", means that the lens position (shooting distance) of the focus lens 33 is "D1" to "D9". Among the image plane movement coefficients K of "K11" to "K19" in the case of, the smallest value is shown.

Similarly, when the lens position (focal length) of the zoom lens 32 is "f2", the image plane movement coefficient K is "D1" when the lens position (shooting distance) of the focus lens 33 is "D1". When "K21" is in "D1" to "D9", it shows the smallest value among "K21" to "K29" which are image plane movement coefficients K. That is, "K21" is the minimum image plane movement coefficient K _min . Hereinafter, similarly, even when each lens position (focal length) of the zoom lens 32 is "f3" to "f9", "K31", "K41", "K52", "K62", "K62" shown in gray are shown. “K72”, “K82”, and “K91” each have a minimum image plane movement coefficient of 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 usually a constant value (fixed value) even if the current lens position of the focus lens 33 changes unless the current lens position of the zoom lens 32 changes. For example, in FIG. 3, “K19”, “K29”, “K39”, “K49”, “K59”, “K69”, “K79”, “K89”, and “K99” shown by hatching are zoomed. It is the maximum image plane movement coefficient K _max indicating the maximum value among the image plane movement coefficients K at each lens position (focal length) of the lens 32.

As described above, as shown in FIG. 3, the lens memory 37 has 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 32. The minimum image plane movement coefficient K _min , which indicates the minimum value of the image plane movement coefficient K for each lens position (focal length), and the image plane movement coefficient K for each lens position (focal length) of the zoom lens 32. The maximum image plane movement coefficient K _max , which indicates the maximum value among them, is stored.

In the above description, the drive regions of the focus lens 33 are set in order from the nearest end to the infinity end (“D1” to “D9”), and the regions (“D1” to “D9”) are set. The minimum value of the image plane movement coefficient K is set to the minimum image plane movement coefficient K _min , and the maximum value is set to the maximum image plane movement coefficient K _max , but the present invention is not limited to this. For example, the close focus position, the close soft limit position, the position of the mechanical end point in the close direction, the position between the close focus position and the position of the mechanical end point in the close direction, as described in FIG. Further, the image plane movement coefficient of the position corresponding to at least one of the positions closer to the mechanical end point in the closest direction may be set as the minimum image plane movement coefficient K _min . Similarly, for example, between the infinite focusing position, the infinite soft limit position, the position of the mechanical end point in the infinite direction, and the position of the mechanical end point in the infinite direction described in FIG. 24 and the like described later. The maximum image plane movement coefficient K _max may be defined as the image plane movement coefficient of the position corresponding to at least one of the position of and the position on the infinite side of the position of the mechanical end point in the infinite direction.

Further, when the value of the optical minimum image plane movement coefficient K _min is, for example, a number having a large number of digits of 102.345, the minimum image plane movement coefficient of 100 or 105, which is a value in the vicinity of 102.345, is used. It may be stored as K _min . When 100 or 105 is stored in the lens memory 37, the number of digits is smaller than when 102.345 is stored in the lens memory 37, so that the memory storage capacity can be saved and the camera control unit 21 will be described later. This is because the capacity of the transmitted data can be suppressed when the two-coefficient K2 (K _min ) is transmitted.

Similarly, when the value of the optical maximum image plane movement coefficient K _max is, for example, a number having a large number of digits of 1534.567, it is a value near 1534.567 and has a smaller number of digits of 1500 or 1535 may be stored as the minimum image plane movement coefficient K _min .

Similarly, the value of optical current position image plane shift factor K _cur, for example, if a large number of digits of 533.246, 530 the number of digits a value in the vicinity of 533.246 is small or 533 may be stored as the current position image plane movement coefficient K _cur .

Further, the values of 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 may be the values of the optical image plane movement coefficient, and the type of lens barrel. , The drive mechanism of the focus lens 33, the detection mechanism of the focus lens 33, and the like may be taken into consideration and set to a value larger or smaller than the value of the optical image plane movement coefficient.

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 by a predetermined angle between an observation position and an imaging position of a subject about a rotation axis 223, and a quick return mirror 221 that is axially supported by the quick return mirror 221. A sub mirror 222 that rotates according to rotation is provided. In FIG. 1, the state in which the mirror system 220 is in the observation position of the subject is shown by a solid line, and the state in which the mirror system 220 is in the imaging position of the subject is shown by a two-dot chain line.

The mirror system 220 is inserted into the optical path of the optical axis L1 when it is in the observation position of the subject, and rotates so as to retract from the optical path of the optical axis L1 when it is in the imaging position of the subject.

The quick return mirror 221 is composed of a half mirror, and when the subject is in the observation position, the quick return mirror 221 reflects a part of the luminous flux (optical axis L2, L3) of the luminous flux (optical axis L1) from the subject. It is guided to the finder 235 and the photometric sensor 237, and a part of the luminous flux (optical axis L4) is transmitted and guided to the sub mirror 222. On the other hand, the sub mirror 222 is composed of a total reflection mirror, and guides the luminous flux (optical axis L4) transmitted through the quick return mirror 221 to the focus detection module 261.

Therefore, when the mirror system 220 is in the observation position, the luminous flux (optical axis L1) from the subject is guided to the finder 235, the photometric sensor 237, and the focus detection module 261 to observe the subject by the photographer and calculate the exposure. And the detection of the focus adjustment state of the focus lens 33 is executed. Then, when the photographer fully presses the release button, the mirror system 220 rotates to the shooting position, all the luminous flux (optical axis L1) from the subject is guided to the image sensor 22, and the captured image data is saved in the camera memory 24. To do.

The light beam (optical axis L2) from the subject reflected by the quick return mirror 221 is imaged on the focal plate 231 arranged on a surface optically equivalent to the image sensor 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 the focus detection area mark and the like on the subject image on the focal plate 231 and displays the subject image and the shutter speed, the aperture value, the number of shots, etc. Display information. As a result, the photographer can observe the subject, its background, shooting-related information, and the like through the finder 235 in the shooting preparation state.

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

The image sensor 22 is provided on the optical axis L1 of the light flux from the subject of the camera body 2 and is provided on the planned focal plane of the photographing optical system including the lenses 31, 32, 33, and 34, and the shutter 23 is provided in front of the image sensor 22. It is provided. The image pickup device 22 has a plurality of photoelectric conversion elements arranged in two dimensions, and can be composed of 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 image-processed by the camera control unit 21 and then recorded in the camera memory 24 which is a recording medium. As the camera memory 24, either a detachable card type memory or a built-in type memory can be used.

The camera control unit 21 drives the focus lens 33 in the lens barrel 3 and performs focus detection. As the focus detection, the camera control unit 21 can detect the focus adjustment state of the photographing optical system by the contrast detection method (hereinafter, appropriately referred to as “contrast AF”) and the focus detection by the phase difference detection method.

In the contrast AF, the camera control unit 21 calculates the focus evaluation value at each position while driving the focus lens 33, and sets the position of the focus lens 33 at which the focus evaluation value is maximum as the focusing position.

Further, in the phase difference detection method, the focus detection module 261 included in the camera body 2 is used. The focus detection module 261 is a pair of line sensors (non-standard) in which a plurality of pixels having a microlens arranged near the planned focal plane of the imaging optical system and a photoelectric conversion element arranged with respect to the microlens are arranged. (Illustrated). Then, 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 with each pixel arranged in the pair of line sensors. Then, the focus adjustment state is detected by obtaining the phase shift of the pair of image signals acquired by the pair of line sensors by a well-known correlation calculation.

The operation unit 28 is an input switch for the photographer to set various operation modes of the camera 1, such as a shutter release button and a movie shooting start switch, and is a still image shooting mode / movie shooting mode switching, an autofocus mode / manual. The focus mode can be switched, and the AF-S mode / AF-F mode can be switched even in the autofocus 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. Further, 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, in the AF-S mode, when the shutter release button is pressed halfway, the position of the focus lens 33 once adjusted is fixed after the focus lens 33 is driven based on the focus detection result. This is the mode for shooting at the focus lens position. The AF-S mode is a mode suitable for still image shooting, and is usually selected when still image shooting is performed. Further, 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, and when the focus state changes, the focus state is changed. , This is a mode for performing search drive (scan drive, search drive) of the focus lens 33. The AF-F mode is a mode suitable for moving image shooting, and is usually selected when performing moving image shooting.

Further, in the present embodiment, as a switch for switching the autofocus mode, a switch for switching the one-shot mode / continuous mode may be provided. Then, 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 configured to be set to.
Next, a method of communicating data 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 connecting portion 202 protruding toward the inner surface side of the body side mount portion 201 is provided at a position near 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 connecting portion 302 protruding toward the inner surface side of the lens side mount portion 301 is provided at a position near the lens side mount portion 301 (inner surface side of the lens side mount portion 301). .. The connection portion 302 is provided with a plurality of electrical contacts.

Then, when the lens barrel 3 is attached to the camera body 2, the electrical contacts of the connection portion 202 provided on the body-side mount portion 201 and the electrical contacts of the connection portion 302 provided on the lens-side mount portion 301 are brought into contact with each other. , Electrically and physically connected. As a result, power can be supplied from the camera body 2 to the lens barrel 3 and data communication between the camera body 2 and the lens barrel 3 becomes possible via the connection portions 202 and 302.

FIG. 4 is a schematic view showing details of the connection portions 202 and 302. Note that the connection portion 202 is arranged on the right side of the body side mount portion 201 in FIG. 4 according to the actual mount structure. That is, the connection portion 202 of the present embodiment is arranged at a position 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. 4).

Similarly, the fact that the connection portion 302 is arranged on the right side of the lens side mount portion 301 means that the connection portion 302 of the present embodiment is arranged 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, and the camera body 2 and the lens barrel 3 are brought into contact with each other. The connection portion 202 and the connection portion 302 are connected to each other, and the electrical contacts provided in both the connection portions 202 and 302 are connected to each other.

As shown in FIG. 4, the connection portion 202 has 12 electrical contacts of BP1 to BP12. Further, the connection portion 302 on the lens barrel 3 side has 12 electrical contacts of LP1 to LP12 corresponding to the 12 electrical contacts on the camera body 2 side, respectively.

The electric contact BP1 and the electric contact BP2 are connected to the first power supply circuit 230 in the camera body 2. The first power supply circuit 230 applies an operating voltage to each part in the lens barrel 3 (excluding circuits having relatively large power consumption such as lens drive motors 321 and 331) via the electric contact BP1 and the electric contact LP1. Supply. The voltage value supplied by the first power supply circuit 230 via the electric contact BP1 and the electric 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). It can be a voltage value near .5V). In this case, the current value supplied from the camera body 2 side to the lens barrel 3 side is a current value in the range of about several tens of mA to several hundreds of mA in the power-on state. Further, the electric contact BP2 and the electric contact LP2 are ground terminals corresponding to the above-mentioned operating voltage supplied via the electric contact BP1 and the electric contact LP1.

The electric contacts BP3 to BP6 are connected to the first communication unit 291 on the camera side, and the electrical contacts LP3 to LP6 are connected to the first communication unit 381 on the lens side corresponding to these electric contacts BP3 to BP6. .. Then, the camera-side first communication unit 291 and the lens-side first communication unit 381 transmit and receive signals from each other using these electrical contacts. The content 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 these electrical contacts BP7 to BP10. .. Then, the camera-side second communication unit 292 and the lens-side second communication unit 382 transmit and receive signals from each other using these electrical contacts. The content of communication performed by the second communication unit 292 on the camera side and the second communication unit 382 on the lens side will be described in detail later.

The electric contact BP11 and the electric contact BP12 are connected to the second power supply circuit 240 in the camera body 2. The second power supply circuit 240 supplies an operating voltage to a circuit having relatively large power consumption, such as the lens drive motors 321 and 331, via the electric contact BP11 and the electric contact LP11. The voltage value supplied by the second power supply circuit 240 is not particularly limited, but the maximum value of the voltage value supplied by the second power supply circuit 240 is the number of maximum values of the voltage values supplied by the first power supply circuit 230. It can be doubled. Further, in this case, the current value supplied from the second power supply circuit 240 to the lens barrel 3 side is a current value in the range of about several tens of mA to several A in the power-on state. Further, the electrical contact BP12 and the electrical contact LP12 are the electrical contacts B.
It is a ground terminal corresponding to the above-mentioned operating voltage supplied via P11 and the electrical contact LP11.

The first communication unit 291 and the second communication unit 292 on the camera body 2 side shown in FIG. 4 constitute the camera communication unit 29 shown in FIG. The camera communication unit 29 may be divided into a camera transmission unit and a camera reception unit. Further, the first communication unit 381 and the second communication unit 382 on the lens barrel 3 side shown in FIG. 4 constitute the lens communication unit 38 shown in FIG. The lens communication unit 38 may be divided into a lens transmitting unit and a lens receiving unit.

Next, communication (hereinafter, referred to as command data communication) between the camera-side first communication unit 291 and the lens-side first communication unit 381 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 an electrical contact. Control data is transmitted from the camera-side first communication unit 291 to the lens-side first communication unit 381 and from the lens-side first communication unit 381 to the camera-side first communication unit 381 via the signal line RDY composed of BP6 and LP6. Command data communication is performed in parallel with transmission of response data to the communication unit 291 at predetermined cycles (for example, 16 millisecond intervals).

FIG. 5 is a timing chart showing an example of command data communication. The camera control unit 21 and the camera-side first 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 communication is possible with the first communication unit 381 on the lens side, and when communication is not possible, the lens control unit 36 and the first communication unit 381 on the lens side increase H (High). The level signal is output. The first communication unit 291 on the camera side does not perform communication with the lens barrel 3 when the signal line RDY is at H level, or does not execute the next process even when communication is in progress.

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

The lens control unit 36 and the lens-side first communication unit 381 change the signal level of the signal line RDY from the L level to the H level in response to the completion of transmission of the lens-side command packet signal 403 (T2). Then, the lens control unit 36 starts the first control process 404 according to the content of the body-side command packet signal 402 received by the time T2.

For example, when the received command packet signal 402 on the body side requests specific data on the lens barrel 3, the lens control unit 36 sets the content of the command packet signal 402 as the first control process 404. Along with the analysis, the process of generating the requested specific data is executed. Further, the lens control unit 36 uses the checksum data included in the command packet signal 402 as the first control process 404 to simplify whether or not there is an error in the communication of the command packet signal 402 from the number of data bytes. It also executes the communication error check process to check the target. The signal of the specific data generated by the first control process 404 is output to the camera body 2 side as a lens side data packet signal 407 (T3). In this case, the camera-side data packet signal 406 output from the camera body 2 side after the command packet signal 402 is dummy data that has no particular meaning to the lens side.
(Including checksum data). In this case, the lens control unit 36 is the second
As the control process 408, the communication error check process as described above is executed using the checksum data included in the camera-side data packet signal 406 (T4).

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

Further, when the second control process 408 is completed, the lens control unit 36 notifies the lens-side first communication unit 381 of the completion of the second control process 408. As a result, the lens control unit 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 one camera side command packet signal 402 and one camera side data packet signal 406. As described above, in the present embodiment, the control data transmitted from the camera body 2 to the lens barrel 3 is divided into two parts for the convenience of processing and transmitted, but the camera side command packet signal 402 and the camera side. Two data packet signals 406 together form one control data.

Similarly, in one command data communication, the lens control unit 36 and the lens side first communication unit 381 transmit one lens side command packet signal 403 and one lens side data packet signal 407, respectively. In this way, the response data transmitted from the lens barrel 3 to the camera body 2 is also divided into two, but the lens-side command packet signal 403 and the lens-side data packet signal 407 are combined into one response data. To 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. 4, the lens control unit 36 has a signal line HEQU composed of electric contacts BP7 and LP7, a signal line HANS composed of electric contacts BP8 and LP8, and a signal line HCLK composed of electric contacts BP9 and LP9. Hotline communication is performed via a signal line HDAT composed of electrical contacts BP10 and LP10 to perform communication at a shorter cycle (for example, 1 millisecond interval) than command data communication.

For example, in the present embodiment, the 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 the hotline communication includes a lens position of the focus lens 33, a lens position of the zoom lens 32, a value related to the image plane movement coefficient, and the like. Here, the value related to the image plane movement coefficient corresponds to the current position image plane movement coefficient K _cur (that is, the lens position (focal length) of the current zoom lens 32 and the lens position (shooting distance) of the current focus lens 33). Image plane movement coefficient), arbitrary coefficient Klow less than or equal to the current position image plane movement coefficient Kcur, minimum image plane movement coefficient K _min , maximum image plane movement coefficient Kmax, etc., which are values required for processing by the camera body 2. is there. A specific example of the processing in the camera body 2 will be described later.

The lens control unit 36 refers to the table showing the relationship between the lens position (zoom lens position and focus lens position) and the image plane movement coefficient K stored in the lens memory 37, thereby referring to the current lens of the zoom lens 32. The current position image plane movement coefficient K _cur corresponding to the position and the current lens position of the focus lens 33 can be obtained. For example, in the example shown in FIG. 3, when the lens position (focal length) of the zoom lens 32 is at "f1" and the lens position (shooting distance) of the focus lens 33 is at "D4", the lens control unit 36 Camera control unit 2 uses "K14" as the current position image plane movement coefficient K _cur by hotline communication.
Send to 1.

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

The camera control unit 21 and the camera-side second communication unit 292 first output an L-level signal to the signal line HEQU in order to start communication by hotline communication (T6). Then, the second communication unit 382 on the lens side 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 the generation process 501 that generates the lens position data. The generation process 501 is a process in which the lens control unit 36 causes the focus lens encoder 332 to detect the position of the focus lens 33 and generate lens position data representing the detection result.

When the lens control unit 36 completes the generation process 501, the lens control unit 36 and the lens-side second communication unit 382 output an L-level signal to the signal line HANS (T7). Then, when this signal is input to the electric contact BP8, the camera control unit 21 and the camera side second communication unit 292 output a clock signal 502 from the electric 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 503 representing lens position data from the electrical contact LP10 to the signal line HDAT in synchronization with the clock signal 502. Then, when the transmission of the lens position data signal 503 is completed, the lens control unit 36 and the lens side second 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 electric contact BP8, the second communication unit 292 on the camera side outputs an H level signal from the electric contact LP7 to the signal line HRQ (T9).
The command data communication and the hotline communication can be executed at the same time or in parallel.

As described above, various information can be transmitted and received between the camera body 2 and the lens barrel 3. For example, the current position image plane movement coefficient K _cur can be transmitted from the lens barrel 3 to the camera body 2. Then, the camera body 2 can realize the following contrast AF by using this current position image plane movement coefficient K _cur .

The camera control unit 21 drives the focus lens 33 at a predetermined sampling interval (distance). Then, the camera control unit 21 calculates the focus evaluation value at each position. The focus evaluation value can be obtained, for example, by extracting the 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 sets the position of the focus lens 33, which maximizes the focus evaluation value, as the focusing position. This focus position is determined, for example, when the focus evaluation value is calculated while driving the focus lens 33, the focus evaluation value rises twice, and then falls further twice. Can be obtained by performing an operation such as an interpolation method using.

For the predetermined sampling interval (distance), for example, it is conceivable that the driving speed (driving amount per unit time) of the focus lens 33 is constant. However, even if the driving speed of the focus lens 33 is constant, the moving speed of the image plane is not always constant. The reason is that the image plane movement coefficient K differs depending on the position of the focus lens 33. As shown in the above equation (1), even if the drive speed of the focus lens 33 is constant, the smaller the image plane movement coefficient K is, the smaller the image plane movement coefficient K is. The moving speed of the image plane increases.

Therefore, if the driving speed of the focus lens 33 is constant, the moving speed of the image plane may become too large. Then, the sampling interval of the focus evaluation value becomes too large, and the focusing position cannot be detected properly. This is because as the sampling interval of the focus evaluation value becomes larger, the variation in the focusing position becomes larger and the focusing accuracy may decrease.

Therefore, the camera body 2 monitors whether the moving speed of the image plane becomes too fast based on the current position image plane moving coefficient K _cur received from the lens barrel 3. More specifically, the camera control unit 21 moves the image plane based on the above drive signal (corresponding to the drive speed of the focus lens 33), the current position image plane movement coefficient K _cur, and the above equation (1). Is calculated. And
The camera control unit 21 adjusts the drive signal so that the moving speed of the image plane does not exceed a predetermined threshold value. This threshold is set so that the moving speed of the image plane when the focus lens 33 is driven becomes a speed at which the focusing position can be appropriately detected.

The camera control unit 21 drives the focus lens 33 at high speed when the search control is started by using the half-press of the release switch as a trigger, and starts the search control by using a condition other than the half-press of the release switch as a trigger. The focus lens 33 may be driven at a low speed. By controlling in this way, it is possible to perform high-speed contrast AF when the release switch is half-pressed, and to perform contrast AF that makes the through image look good when the release switch is not half-pressed. Is. The through image is, for example, an image for a monitor captured by an image sensor at a predetermined frame rate before a shooting instruction (fully pressing the shutter button).

Further, the camera control unit 21 may control the focus lens 33 to be driven at a high speed in the search control in the still image shooting mode, and to drive the focus lens 33 at a low speed in the search control in the moving image shooting mode. This is because, by controlling in this way, it is possible to perform high-speed contrast AF in the still image shooting mode, and perform contrast AF in which the appearance of the moving image is suitable in the moving image shooting mode.

Further, 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 sports shooting mode and the contrast AF at low speed in the landscape shooting mode. Further, the driving speed of the focus lens 33 in the search control may be changed according to the focal length, the photographing distance, the aperture value, and the like.
In this way, the camera body 2 can perform the contrast AF processing with high accuracy by receiving the current position image plane movement coefficient K _cur .

Next, an operation example of the camera 1 according to the present embodiment will be described with reference to FIG. 7. FIG. 7 is a flowchart showing the operation of the camera 1 according to the present embodiment. The following operations are started when the power of the camera 1 is turned on.

First, in step S101, the camera body 2 communicates to identify the lens barrel 3. This is because the communication format that can be communicated differs depending on the type of lens barrel. Then, the process proceeds to step S102, and in step S102, the camera control unit 21 determines whether or not the lens barrel 3 is a lens corresponding to a predetermined first type communication format. As a result, if 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, when the camera control unit 21 determines that the lens barrel 3 is a lens that does not correspond to a predetermined first type communication format, the camera control unit 21 proceeds to step S112. Further, when the camera control unit 21 determines that the lens barrel 3 is a lens corresponding to a second type communication format different from the first type 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 corresponding to the first type and the second type of communication type, the camera control unit 21 may proceed to step S103.

Next, in step S103, it is determined whether or not the photographer has turned on the live view shooting on / off switch provided in the operation unit 28, and when the live view shooting is turned on, the mirror system 220 Is 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 hotline communication, as described above, when the lens control unit 36 receives the L level signal (request signal) output to the signal line HRQ by the camera control unit 21 and the camera side second communication unit 292, The lens information is transmitted to the camera control unit 21, and such transmission of the lens information is repeated. The lens information includes, for example, 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 , and the like.
It contains at least one piece of information such as a minimum image plane movement coefficient K _min , a maximum image plane movement coefficient K _max , a first coefficient K1, a second coefficient K2, and a third coefficient K3, which will be described later. The hotline communication is repeated after step S104. Hotline communication is repeated, for example, until the power switch is turned off.

For example, when transmitting lens information to the camera control unit 21, the lens control unit 36 refers to a table (see FIG. 3) showing the relationship between each lens position stored in the lens memory 37 and the image plane movement coefficient K. Then, 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 minimum image plane movement coefficient K _min corresponding to the current lens position of the zoom lens 32. , And the maximum image plane movement coefficient K _max can be obtained. Then, using at least one of 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 , the first coefficient K1, the second coefficient K2, and the third coefficient K3 are used.
Is set, and lens information including the first coefficient K1, the second coefficient K2, and the third coefficient K3 can be transmitted to the camera control unit 21.

Here, in the present embodiment, when the lens control unit 36 transmits the first coefficient K1, the second coefficient K2, and the third coefficient K3 to the camera control unit 21, the characteristics and usage state of the lens barrel are adjusted. The first coefficient K1, the second coefficient K2, and the third coefficient K3 can be arbitrarily set accordingly. The lens control unit 36 describes the characteristics and usage conditions of the lens barrel (optical characteristics of the focus lens and zoom lens, speed and acceleration / deceleration characteristics of the motor that drives the focus lens and zoom lens, motor that drives the focus lens and zoom lens, etc. Drive sound generated when driving the drive mechanism, placement and sensitivity of sensors that detect the position of the focus lens and zoom lens, motor that drives the focus lens and zoom lens, amount of play in the drive mechanism, usage period of the lens barrel, lens The first coefficient K1, the second coefficient K2, and the third coefficient K3 are arbitrarily set according to the temperature of the lens barrel, etc.), and the camera control unit 2
This is because by controlling 1 using at least one of the first coefficient K1, the second coefficient K2, and the third coefficient K3, various controls can be performed according to the characteristics of the lens barrel, the state of use, and the like. ..

For example, the lens control unit 36 sets the current position image plane movement coefficient K _cur as the first coefficient K1, sets the minimum image plane movement coefficient K _min as the second coefficient K2, and sets the maximum image plane movement as the third coefficient K3. The coefficient K _max can be set. Further, the lens control unit 36 has the current position image plane movement coefficient K _cur , the minimum image plane movement coefficient K _min × 0.9, and the maximum image plane movement coefficient as the first coefficient K1, the second coefficient K2, and the third coefficient K3. It may be set as K _max × 1.2 or the like. In addition, the lens control unit 3
6 is the current position image plane movement coefficient K _cur as the first coefficient K1, the second coefficient K2, and the third coefficient K3.
, K _min −0.2 × (K _cur −K _min ), K _max −0.2 × (K _cur −K _max ), and the like. For example, the first coefficient K1, the second coefficient K2, and the third coefficient K3 are set by performing predetermined four arithmetic operations on the current position image plane movement coefficient Kcur, the maximum image plane movement coefficient Kmax, and the minimum image plane movement coefficient Kmin. You may.

Further, in the present embodiment, the first coefficient K1 (current position image plane movement coefficient K _cur ), the second coefficient K2 (minimum image plane movement coefficient K _min ), and the third coefficient K3 (maximum image plane movement) are performed by hotline communication. The coefficient K _max ) is repeatedly transmitted to the camera control unit 21. That is, in the present embodiment, the first
In the processing period of, the first coefficient K1, the second coefficient K2, and the third coefficient K3 are transmitted as a set, and then in the second processing period following the first processing period, the first coefficient K1 and the second coefficient K1 are transmitted. The coefficient K2 and the third coefficient K3 are set and transmitted. Then, in the third processing period following the second processing period, the first coefficient K1, the second coefficient K2, and the third coefficient K3 are set and transmitted.

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

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

Then, in step S107, the search drive speed V, which is the drive speed of the focus lens 33 in the search operation, is based on the second coefficient K2 (minimum image plane movement coefficient K _min ) acquired in step S104 by the camera control unit 21. The process of determining is performed.

In the present embodiment, the search operation is a focus evaluation value by the contrast detection method by the camera control unit 21 while driving the focus lens 33 at the search drive speed V determined in step S107 by the focus lens drive motor 331. Is an operation in which the calculation of the above is performed at the same time at a predetermined interval, and the detection of the focusing position by the contrast detection method is executed at a predetermined interval.

Further, in this search operation, when the focusing position is detected by the contrast detection method, the camera control unit 21 calculates the focus evaluation value at a predetermined sampling interval while driving the focus lens 33 for the search. The lens position where the calculated focus evaluation value peaks is detected as the in-focus position. Specifically, the camera control unit 21 searches and drives the focus lens 33 to move the image plane of the optical system in the optical axis direction, thereby calculating the focus evaluation values on different image planes, and these focal points. The lens position where the evaluation value peaks is detected as the in-focus position. However, on the other hand, if the moving speed of the image plane is made too fast, the distance between the image planes for which the focus evaluation value is calculated becomes too large, and the in-focus position may not be detected properly. .. In particular, the image plane movement coefficient K, which indicates 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 in the optical axis direction of the focus lens 33, so that the focus lens 33 has a constant speed. Even when driven by, the moving speed of the image plane becomes too fast depending on the lens position of the focus lens 33. Therefore, the distance between the image planes for which the focus evaluation value is calculated becomes too large, and the focusing position is adjusted. It may not be possible to detect it properly.

Therefore, in the present embodiment, the camera control unit 21 sets the search drive speed V when performing the search drive of the focus lens 33 based on the second coefficient K2 (minimum image plane movement coefficient K _min ) acquired in step S104. calculate. The camera control unit 21 has a drive speed that allows the focus position to be appropriately detected by the contrast detection method using the second coefficient K2 (minimum image plane movement coefficient K _min ), and is the maximum drive. The search drive speed V is calculated so as to be the speed. Here, since the second coefficient K2 is a value set according to the characteristics of the lens barrel, the usage state, and the like, the camera control unit 21 controls the lens barrel by using the second coefficient K2. It can be controlled according to the characteristics and usage conditions.

Then, in step S108, the search operation is started at the search drive speed V determined in step S107. Specifically, the camera control unit 21 sends a search 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 search-driven at the search drive speed V determined in step S107. Then, the camera control unit 21 reads out the pixel output from the image pickup pixel of the image pickup element 22 at predetermined intervals while driving the focus lens 33 at the search drive speed V, and calculates the focus evaluation value based on this. As a result, the focusing position is detected by the contrast detection method by acquiring the focus evaluation values at different focus lens positions.

Next, in step S109, the camera control unit 21 determines whether or not the peak value of the focus evaluation value can be detected (whether or not the in-focus position can be 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 the focus lens 33 is driven to a predetermined drive end. Is repeated. On the other hand, when the peak value of the focus evaluation value can be detected, the process proceeds to step S110.

When the peak value of the focus evaluation value can be detected, the process proceeds to step S110. In step S110, the camera control unit 21 issues a command to the lens control unit 36 to drive the lens to a position corresponding to the peak value of the focus evaluation value. Send. The lens control unit 36 controls the drive of the focus lens 33 according to the received command.

Next, the process proceeds to step S111, and 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), shooting control of a still image is performed. After the shooting control is completed, the process returns to step S104 again.

On the other hand, if it is determined in step S102 that the lens barrel 3 is a lens that does not correspond to 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, the current position image plane movement coefficient K _cur is included as the lens information when the lens information is repeatedly transmitted by the hot line communication between the camera body 2 and the lens barrel 3. , 1st coefficient K1
, The point at which information that does not include the information of the second coefficient K2 and the third coefficient K3 is transmitted (step S113), and the search drive speed V, which is the drive speed of the focus lens 33 in the search operation, are determined. Except for the point (step S116) in which the current position image plane movement coefficient K _cur included in the lens information is used instead of the second coefficient K2 (minimum image plane movement coefficient K _min ).
The same process as in steps S103 to S111 described above is executed.

In the present embodiment, the lens control unit 36 arbitrarily sets the first coefficient K1, the second coefficient K2, and the third coefficient K3 according to the characteristics of the lens barrel, the usage state, and the like, and the camera control unit 21 is the first. By controlling using at least one of the coefficient K1, the second coefficient K2, and the third coefficient K3, various controls can be performed according to the characteristics of the lens barrel, the usage state, and the like. In this embodiment, the first coefficient K1 (current position image plane movement coefficient K _cur ), the second coefficient K2 (minimum image plane movement coefficient K _min ), and the third coefficient K3 (maximum image plane movement coefficient K _max ) are used. The example of transmission has been described in detail, but the present invention is not limited to this. For example, the lens control unit 36 has a first coefficient K1 = current position image plane movement coefficient K _cur , a second coefficient K2 = current position image plane movement coefficient K _cur or less, and a third coefficient K3 = current position image plane movement coefficient. It may be set as a value equal to or higher than K _cur .
(Second Embodiment)

In the second embodiment, the camera body 2 determines whether to allow or prohibit high-speed search during the contrast AF process by using the second coefficient K2. The specific setting method of the second coefficient K2 in this embodiment will be described later.

When high-speed search is prohibited, the camera control unit 21 acquires focus evaluation values on a plurality of image planes while driving the focus lens 33 at the first search speed (low speed) in the first search range, and obtains the acquired focus evaluation. The position of the focus lens 33 at which the value peaks is searched (hereinafter, this low-speed search operation is referred to as "first search operation"). When the position of the focus lens 33 that becomes the peak is found, the focusing drive is performed. If the position of the focus lens 33 that becomes the peak is not found even after the first search operation for the first search range, the first search operation is performed for the range other than the first search range, and the position of the focus lens 33 that becomes the peak is performed. If is found, focus drive is performed.

When the high-speed search is permitted, the camera control unit 21 first performs the first search operation in the first search range, and when the position of the focus lens 33 to be the peak is found, the camera control unit 21 performs the focusing drive. When the peak of the focus evaluation value is not obtained even if the first search operation is performed for the first search range, the camera control unit 21 drives the focus lens 33 at the second search speed (high speed) for a range other than the first search range. While acquiring the focus evaluation values on a plurality of image planes, the position of the focus lens 33 at which the focus evaluation value peaks is roughly detected (hereinafter, the search operation at high speed following the first search operation is described as ". Second search operation "). When the position of the focus lens 33 that becomes the peak is found by the second search operation, a plurality of positions including the peak position found by the second search operation are driven while driving the focus lens 33 at the third search speed (low speed). The focus evaluation value is acquired on the image plane of the lens, and the position of the focus lens 33 at which the focus evaluation value peaks is searched in detail (hereinafter, the low-speed search operation following the second search operation is referred to as "third search operation"). .. When the position of the focus lens 33 that becomes the peak is found by performing the third search operation, focusing drive is performed. The third search speed may be slower than the second search speed, and the third search speed and the first search speed may be equal.
In the present embodiment, when performing the contrast AF process, the camera control unit 21 first determines whether to allow or prohibit the high-speed search.

FIG. 8 is a sequence diagram showing an example of high-speed search determination processing. The figure shows the process from the start of the contrast AF process to the determination of whether to allow or prohibit the high-speed search.

In step S11, the image sensor 22 receives the light flux from the photographing optical system, and the image pickup for displaying the through image is performed. Then, the camera control unit 21 receives the image signal output from the image sensor 22 and generates a through image. The through image is displayed on the liquid crystal monitor (not shown) of the camera body 2.
In step S12, the camera control unit 21 determines whether or not the shutter release button is half-pressed (the first switch SW1 is turned on).
When the first switch SW1 is not turned on (NO in step S12), the camera control unit 21 repeatedly determines whether or not the first switch SW1 is half-pressed until the first switch SW1 is turned on.

When the first switch SW1 is on (YES in step S12), in step S13, the camera control unit 21 drives the focus lens 33 to a predetermined initial lens position (initial drive). The initial lens position in the initial drive is not particularly limited, and may be, for example, a position closer to the camera body 2 or a position closer to the subject than the current position, or a position determined by the shooting scene. Further, step S13 may be omitted and the focus lens 33 may be left at the current position without performing the initial drive.

In step S14, the lens communication unit 38 of the lens barrel 3 transmits the maximum drive speed Vmax_lns (pulse / sec), which is the maximum speed that the focus lens 33 can drive, and the second coefficient K2 to the camera body 2. .. The maximum drive speed Vmax_lns is stored in, for example, the lens memory 37. The lens communication unit 38 may transmit the maximum drive speed Vmax_lns and the second coefficient K2 by hotline communication, or may transmit in response to a transmission request from the camera body 2.
In step S15, the camera communication unit 29 of the camera body 2 receives the maximum drive speed Vmax_lns and the second coefficient K2.

Here, the maximum driving speed Vmax_lns is the driving speed of the focus lens 33, not the moving speed of the image plane. Therefore, in step S16, the camera control unit 21 converts the maximum drive speed Vmax_lns into the maximum image plane movement speed Vmax_img (mm / sec) using the second coefficient K2. Specifically, the camera control unit 21 calculates the maximum image plane moving speed Vmax_img based on the following equation (2).
Vmax_img = Vmax_lns / K2 ... (2)

For example, when the second coefficient K2 is the current position image plane movement coefficient K _cur , the maximum image plane movement speed Vm.
ax_img corresponds to the image plane moving speed when the focus lens 33 is driven at the maximum driving speed Vmax_ls at the current position of the focus lens 33. Further, for example, when the second coefficient K2 is the minimum image plane movement coefficient K _min , the maximum image plane movement speed Vmax_img is
This corresponds to the image plane moving speed when the focus lens 33 is driven at the maximum driving speed Vmax_lns at the position where the image plane moving coefficient becomes the minimum value. The maximum image plane movement speed Vmax_img when the second coefficient K2 is the minimum image plane movement coefficient K _min is larger than the maximum image plane movement speed Vmax_img when the second coefficient K2 is the current position image plane movement coefficient K _cur. It becomes.

In step S17, the camera control unit 21 acquires the first search speed V1 during the first search operation. The first search speed V1 is the image plane moving speed when the focus lens 33 is driven in the first search operation. For example, the image plane moving speed (focus detection image plane moving) capable of detecting the in-focus position with a predetermined accuracy or higher. Speed). As a specific example, when the acquisition interval of the focus evaluation value capable of detecting the focus position is about 300 μm in terms of the image plane movement amount and the time interval for calculating the focus evaluation value is 1/60 second, the camera control The unit 21 can set the first search speed V1 to 300 × 60 = 18000 (μm / sec) = 18 (mm / sec).

When the aperture 35 is stopped down, the depth of focus becomes deeper, so that the acquisition interval of the focus evaluation value capable of detecting the in-focus position may become longer. In this case, the first search speed V1 can be further increased. Further, the camera control unit 21 does not necessarily have to calculate the first search speed V1, and may be stored in the camera memory 24 in the camera body 2 in advance and read out, or may be read out in the lens barrel 3. It may be stored in the lens memory 37 and received from the lens barrel 3.
In step S18, the camera control unit 21 determines whether or not the relationship of the following equation (3) is satisfied.
Vmax_img * A = Vmax_lns / K2 * A ≧ V1 (where 0 <A ≦ 1) ・ ・ ・ (3)
Here, A is a predetermined constant, and can be, for example, 0.8 to 0.9.

When the above formula (3) is not satisfied (NO in step S18), it is determined that the maximum image plane moving speed Vmax_img and the first search speed V1 are about the same speed. In this case, in step S19, the camera control unit 21 prohibits high-speed search. This is because the first search speed V1 is sufficiently high and it is not necessary to switch to the second search speed V2. When the high-speed search is prohibited, as described above, the camera control unit 21 performs the first search operation in the first search range, and when the position of the focus lens 33 to be the peak is found, the camera control unit 21 performs the focusing drive. If the position of the focus lens 33 that becomes the peak is not found even after the first search operation for the first search range, the first search operation is performed for a range other than the first search range (for example, the entire range), and the peak is performed. When the position of the focus lens 33 is found, the focusing drive is performed.

On the other hand, when the above formula (3) is satisfied (YES in step S18), it is determined that the maximum image plane moving speed Vmax_img is sufficiently faster than the first search speed V1. In this case, in step S20, the camera control unit 21 allows high-speed search. Since the second search speed V2 is much faster than the first search speed V1, it is expected that a range other than the first search range (for example, the entire range) can be searched quickly by switching to the second search speed V2. Because it can be done. When the high-speed search is permitted, as described above, the camera control unit 21 performs the first search operation in the first search range, and when the position of the focus lens 33 to be the peak is found, the camera control unit 21 performs the focusing drive. When the peak of the focus evaluation value is not obtained even after performing the first search operation for the first search range, the camera control unit 21 performs the second search operation for a range other than the first search range. When the position of the focus lens 33 that becomes the peak is found by the second search operation, the third search operation is performed for the range including the peak position found by the second search operation, and the position of the focus lens 33 that becomes the peak is determined. When found, focus drive is performed.
As described above, it is determined whether to prohibit or allow high-speed search. Subsequently, each operation when the high-speed search is prohibited and when the high-speed search is permitted will be described.

FIG. 9 is a flowchart showing the operation of the camera 1 when the high-speed search is prohibited, and steps S31 to S33 in the figure correspond to the first search operation. Further, FIG. 10 is a diagram illustrating the operation of the camera 1 when the high-speed search is prohibited. It is assumed that the initial drive (step S13 in FIG. 8) is performed at times t1 to t2 in FIG.

In step S31 of FIG. 9, the camera control unit 21 drives the focus lens 33 so that the image plane movement speed becomes the first search speed V1 based on the current position image plane movement coefficient K _cur, and sets the focus evaluation value. Acquire (after time t2 in FIG. 10). The method of calculating the focus evaluation value is not particularly limited. For example, the camera control unit 21 processes the image signal received from the image sensor 22 with a high-frequency filter, and integrates the filtered image signal to evaluate the focus. The value can be calculated.

In step S32 of FIG. 9, the camera control unit 21 determines whether or not a peak of the focus evaluation value has been detected. For example, when the focus evaluation value rises twice and then falls twice, the camera control unit 21 determines that a peak has been detected.

If the peak is not detected (NO in step S32), in step S33, the camera control unit 21 determines whether or not the first search range has been searched. The first search range is, for example, a part of the entire search range (the entire range of the focus adjustable range). If the search in the first search range is not completed (NO in step S33), the process returns to step S31 and the first search operation is continued.

When the first search range has been searched (YES in step S33), in step S34, the camera control unit 21 drives the focus lens 33 at the first search speed V1 and acquires the focus evaluation value (first search). motion). Subsequently, in step S36, the camera control unit 21 determines whether or not a peak of the focus evaluation value has been detected. When the peak is not detected (NO in step S36), in step S37, the camera control unit 21 determines whether or not the entire second search range has been searched. The second search range may be the entire search range, or may be a range obtained by excluding the range already searched in steps S31 to S33 from the entire search range (focus adjustable range). If the search for the entire second search range is not completed (NO in step S37), the process returns to step S34 and the first search operation is continued. When the entire second search range has been searched (YES in step S37), the in-focus position could not be detected even after searching the entire search range. Therefore, in step S45, the camera control unit 21 positions the focus lens 33 at a predetermined position. Drive to. The predetermined position is not particularly limited, and may be, for example, a predetermined position, a position where the focus evaluation value is maximized, or the current position may be left as it is. Further, the fact that the focusing position could not be detected may be displayed on the liquid crystal monitor (not shown) of the camera body 2.

On the other hand, when a peak is detected in step S32 (YES in step S32, time t3 in FIG. 10), in step S35 in FIG. 9, the camera control unit 21 drives the focus lens 33 to the in-focus position (focus). Focus drive, time t3 to t4 in FIG. 10). That is, the camera control unit 21 calculates the focusing position by performing an interpolation method or other calculation using the focus evaluation values of several points before and after the peak focus evaluation value. Then, the camera control unit 21 drives the focus lens 33 to the in-focus position. At this time, the camera control unit 21 may calculate the amount of movement of the image plane in consideration of the current position image plane movement coefficient K _cur , and drive the focus lens 33 more accurately. Even when the peak is detected in step S36, the camera control unit 21 drives the focus lens 33 to the focusing position (focusing drive).

FIG. 11 is a flowchart showing the operation of the camera 1 when the high-speed search is permitted. Steps S31, S32 and S41 in the figure correspond to the first search operation, steps S42 to S44 correspond to the second search operation, and steps S46 to S48 correspond to the third search operation. Further, FIG. 12 is a diagram illustrating the operation of the camera 1 when the high-speed search is permitted. It is assumed that the initial drive (step S4 in FIG. 8) is performed at times t11 to t12 in FIG.

The camera 1 first performs the first search operation (steps S31, S32, S41 in FIG. 11, times t12 to t13 in FIG. 12). When the peak of the focus evaluation value is detected by the first search operation (YES in step S32), the camera 1 performs focusing drive in step S35. Since steps S31, S32 and S35 in FIG. 11 are almost the same as those in FIG. 9, detailed description thereof will be omitted.

As a difference from FIG. 9, in step S41 of FIG. 11, the camera control unit 21 determines whether or not the entire first search range has been searched. The first search range is a range narrower than the entire search range, and is, for example, a predetermined range starting from the position of the focus lens 33 after the initial drive. If the search in the first search range is not completed (NO in step S41), the process returns to step S31 and the first search operation is continued.

If the peak value of the focus evaluation value cannot be detected even after searching the entire first search range (YES in step S41), it is assumed that the in-focus position cannot be obtained within the first search range, and the camera 1 is second. Move to search operation.

That is, in step S42, the camera control unit 21 drives the focus lens 33 at the second search speed V2 and acquires the focus evaluation value (after the time t13 in FIG. 12). The driving direction of the focus lens 33 in the second search operation is the same as that in the first search operation.

Here, the second search speed V2 is a value larger than the first search speed V1. The second search speed V2 may be any speed as long as it can detect the peak of the focus evaluation value, and does not necessarily have to be a speed at which the in-focus position can be detected. For example, the second search speed V2 can be set to 50 to 100 (mm / sec).

Subsequently, in step S43, the camera control unit 21 determines whether or not a peak of the focus evaluation value has been detected. For example, when the focus evaluation value rises twice and then falls twice, the camera control unit 21 determines that a peak has been detected.

When the peak is not detected (NO in step S43), in step S44, the camera control unit 21 determines whether or not the entire second search range has been searched. The second search range may be the entire search range, or may be a range obtained by excluding the already searched first search range from the entire search range (focus adjustable range). If the search for the entire second search range is not completed (NO in step S44), the process returns to step S42 and the second search operation is continued.

When the entire second search range has been searched (YES in step S44), the focusing position could not be detected even after searching the entire search range. Therefore, in step S45, the camera control unit 21 positions the focus lens 33 at a predetermined position. Drive to. The predetermined position is not particularly limited, and may be, for example, a predetermined position, a position where the focus evaluation value is maximized, or the current position may be left as it is. Further, the fact that the in-focus position could not be detected may be displayed on the liquid crystal monitor (not shown) of the camera body 2.

Even if a peak is detected in step S43 (YES in step S43, time t14 in FIG. 10), it is desirable not to drive the focus immediately. This is because the focus lens 33 is driven at high speed in the second search operation, so that the sampling interval is coarse and the focusing position cannot always be accurately specified. Therefore, the camera 1 performs the third search operation as follows.

In step S46, the camera control unit 21 drives the focus lens 33 at the third search speed V3 and acquires the focus evaluation value (after the time t14 in FIG. 12). The drive direction of the focus lens 33 in the third search operation is opposite to that in the second search operation.

The third search speed V3 is a speed based on the image plane moving speed that drives the focus lens 33 in the third search operation, and can be, for example, an image plane moving speed that can detect the in-focus position. The third search speed V3 may be equal to the first search speed V1.

Subsequently, in step S47, the camera control unit 21 determines whether or not a peak of the focus evaluation value has been detected. For example, when the focus evaluation value rises twice and then falls twice, the camera control unit 21 determines that a peak has been detected.

When the peak is not detected (NO in step S47), in step S48, the camera control unit 21 determines whether or not the entire third search range has been searched. The third search range is a predetermined range starting from the position of the focus lens 33 when a peak is detected in the second search operation. If the search in the third search range is not completed (NO in step S48), the process returns to step S46 and the third search operation is continued.

If the entire third search range has been searched (YES in step S48), the camera control unit 21 drives the focus lens 33 to a predetermined position in step S45, assuming that the focusing position cannot be detected.

When a peak is detected in step S47 (YES in step S47, time t15 in FIG. 12), in step S35 in FIG. 11, the camera control unit 21 drives the focus lens 33 to the in-focus position (FIG. 12). Times t15 to t16).

As described above, the camera 1 can perform the contrast AF process after performing the high-speed search determination using the second coefficient K2. By performing a high-speed search, the focus lens 33 is moved to the in-focus position in a short time even when the in-focus position is far from the initial lens position (the position of the focus lens 33 when the initial drive is completed). Can be made to.

By the way, whether to allow or prohibit high-speed search is determined based on the above equation (3). Therefore, the smaller the second coefficient K2 is set, the easier it is for high-speed search to be permitted, and focusing in a short time is expected.

On the other hand, in high-speed search, it is necessary to drive the focus lens 33 at a second search speed V2, which is faster than the first search speed V1. Further, at the start of the third search operation, it is necessary to stop the focus lens 33 driven at such a second search speed V2. As a result, if the high-speed search is performed too frequently, the life of the drive motor 331 that drives the focus lens 33 may be shortened.

Therefore, it is preferable to set the second coefficient K2 in consideration of the balance between the time until focusing and the life of the drive motor 331. That is, the second coefficient K2 may be set to a small value when focusing in a short time is important, and the second coefficient K2 may be set to a large value when the life of the drive motor 331 is important.

Further, considering the relationship between the current position image plane movement coefficient K _cur and the second coefficient K2, it becomes as follows. When the high-speed search is not performed, the entire search range is searched at the first search speed V1 (that is, the image plane moving speed at which the in-focus position can be detected). Then, according to the above equation (1), the driving speed of the focus lens 33 for setting the image plane moving speed to the first search speed V1 becomes slower as the current position image plane moving coefficient K _cur becomes smaller.

Therefore, the smaller the current position image plane movement coefficient K _cur , the slower the driving speed of the focus lens 33, and as a result, the longer the focusing time when the high-speed search is not performed. On the contrary, the larger the current position image plane movement coefficient K _{cur, the} shorter the focusing time when the high-speed search is not performed.

Therefore, the smaller the current position image plane movement coefficient K _cur , the higher the need for high-speed search, and for that purpose, it is better to reduce the second coefficient K2. On the other hand, the current position image plane movement coefficient K _cur
The larger the value, the lower the need for high-speed search, and the second coefficient K2 may be increased.

Then, as one criterion, it is desirable that the second coefficient K2 is equal to or less than the current position image plane movement coefficient K _cur . If when the second coefficient K2 is greater than the current position image plane shift factor K _cur, the second coefficient becomes large when the current position image plane shift factor K _cur is small, because the high-speed search becomes difficult to allow. According to the above criteria, when the current position image plane movement coefficient K _cur is small, the second coefficient K2 becomes small, and when the current position image plane movement coefficient K _cur is large, the second coefficient becomes large.

Considering the above, as a specific setting example of the second coefficient K2, when focusing in a short time is emphasized, it is conceivable that the second coefficient K2 is set to the minimum image plane movement coefficient K _min . On the other hand, when the life of the drive motor 331 is important, it is conceivable that the second coefficient K2 is set to the current position image plane movement coefficient K _cur . Of course, the second coefficient K2 may be a value between the current position image plane movement coefficient K _cur and the minimum image plane movement coefficient K _min , or may be a value less than the minimum image plane movement coefficient K _min .

As described above, in the second embodiment, the second coefficient K2 is used to determine whether to allow or prohibit the high-speed search. By performing a high-speed search, the time required for focusing can be shortened. Further, the balance between the time to focus and the drive motor 331 can be adjusted on the lens barrel 3 side by the value of the second coefficient K2.

For example, when the focusing position is sufficiently far from the initial lens position, the entire second search range is searched at the second search speed V2 as compared with the case where the entire second search range is searched at the first search speed V1. Focusing is expected in a short time when performing a high-speed search. However, when a high-speed search is performed at the second search speed V2, focusing is hindered in a short time by the amount of searching at the third search speed V3 after the high-speed search.

Therefore, when the focusing position is separated from the initial lens position by a predetermined distance or more, the lens control unit 36 sets the second coefficient K2 to be small so that high-speed search is easily permitted, and the focusing position is from the initial lens position. When the distance is shorter than the predetermined distance, the second coefficient K2 may be set large to make it difficult for high-speed search to be permitted.

For example, the camera control unit 21 determines whether or not the focusing position is closer than a predetermined distance from the initial lens position in consideration of the magnitude of the focus evaluation value, the variation in the focus evaluation value, the amount of change in the focus evaluation value, and the like. The result is transmitted to the lens control unit 36, and the lens control unit 36 can set the magnitude of the second coefficient K2 based on the determination result transmitted by the camera control unit 21. For example, when the second coefficient K2 is the current position image plane movement coefficient K _cur , the second coefficient K2 is set larger than when the second coefficient K2 is the minimum image plane movement coefficient K _min . As described above, the camera control unit 21 determines whether to allow or prohibit the high-speed search based on the above equation (3).

Further, the lens control unit 36 sets the second coefficient K2 to be small when the previous focusing position and the initial lens position are separated by a predetermined distance or more, and the previous focusing position and the initial lens position are set to be smaller than the predetermined distance. When they are close to each other, the second coefficient K2 may be set large.

Further, the lens control unit 36 or the camera control unit 21 has a determination unit (not shown) for determining a shooting scene, a shooting state, etc., and the lens control unit 36 is like sports shooting for shooting a subject with violent movement. The second coefficient K2 may be set small when a relatively large out-of-focus condition is likely to occur, and the second coefficient K2 may be set large when a relatively large out-of-focus condition is unlikely to occur as in a landscape photograph in which the subject is stationary.

For example, the determination unit determines the photometric value by the photometric sensor when the output of the angular velocity sensor (gyro) for detecting camera shake fluctuates by a predetermined value or more, when the variation of the focus evaluation value is equal to or more than a predetermined value. When the value varies by more than or equal to the value, it can be judged that a relatively large out-of-focus case is likely to occur. When the determination unit is provided in the camera control unit 21, the lens control unit 36 can set the magnitude of the second coefficient K2 based on the determination result transmitted by the camera control unit 21.

Further, if the photographer does not operate the focus operation ring before the predetermined period, the lens control unit 36 is likely to have a relatively large out-of-focus condition, so the second coefficient K2 is set small and the predetermined period is set. If the photographer has operated the focus operation ring before, it is unlikely that a relatively large out-of-focus condition has occurred, so the second coefficient K2 may be set large.

Further, the lens control unit 36 sets the second coefficient K2 to be small when the entire search range is a lens barrel of a predetermined distance or more (a lens barrel that takes a predetermined time to search the entire search range), and the entire search range is set. When is a lens barrel less than a predetermined distance (a lens barrel that does not take a predetermined time to search the entire search range), the second coefficient K2 may be set large.

Further, in the above-described embodiment, an example in which the lens control unit 36 transmits the minimum image plane movement coefficient K _min or the current position image plane movement coefficient K _cur as the second coefficient K2 has been described in detail, but the present invention is limited to this. It's not something. For example, as shown in FIGS. 13 and 14, the lens control unit transmits a value from the minimum image plane movement coefficient K _min to the current position image plane movement coefficient K _cur as the second coefficient K2 according to a predetermined condition. As the second coefficient K2, a value smaller than the minimum image plane movement coefficient K _min to the current position image plane movement coefficient K _cur may be transmitted.

This will be described in detail with reference to FIG. The lens control unit 36 detects the distance between the previous focusing position and the initial lens position, and sets the second coefficient K2 according to the detected distance. For example, when the distance between the previous focusing position and the initial lens position is separated by 0.5 or more of the entire search range, the second coefficient K2 = K _min is set, and the previous focusing position and the initial lens position are set. The distance is the entire search range x 0.5
If less than, and if the total search range x 0.3 or more is separated, if the total search range x 0.3 or more, and if the total search range x 0.1 or more is separated, the total search range x less than 0.1 distance If so, K _{min +0.3} × (K _cur −K _min ), K _min +0.6 × (K _cur −K _min ), and K _cur are set as the second coefficient K2, respectively. The lens control unit is in step S1 of FIG. 8 described above.
In 4, the second coefficient K2 set in response to the transmission request from the camera body 2 is transmitted.

This will be described in detail with reference to FIG. In the lens barrel 3 of this embodiment, the second coefficient K2 is stored in the lens memory 37 in advance at the time of shipment from the factory. For example, the lens barrel 3 that takes 3 seconds or more to search the entire search range stores a minimum image plane movement coefficient K _min × 0.5 as the second coefficient K2. The lens barrel 3 which takes less than 3s and 2s or more to search the entire search range, the lens barrel 3 which takes less than 2s and 1s or more to search the entire search range, and the lens barrel 3 which takes less than 1s have the second coefficient K2. As K _min × 0.5 + 0.3 × (K _cur −K _min ), K _min × 0.5 + 0.6 × (K _cur −K _min ), and K _cur are stored, respectively. In step S14 of FIG. 8 described above, the lens control unit transmits the second coefficient K2 stored in the lens memory 37 in response to the transmission request from the camera body 2.
(Third Embodiment)

In the third embodiment, the camera body 2 makes an abnormality determination using the first coefficient K1 and the second coefficient K2. In the present embodiment, the second coefficient K2 may be a value equal to or less than the first coefficient K1, and is not particularly limited.
FIG. 15 is a sequence diagram showing an example of abnormality determination processing.

In step S1, the lens communication unit 38 of the lens barrel 3 transmits the first coefficient K1 (that is, the current position image plane movement coefficient K _cur ) and the second coefficient K2 to the camera body 2.
In step S2, the camera communication unit 29 of the camera body 2 receives the first coefficient K1 and the second coefficient K2.

In step S3, the camera control unit 21 determines whether or not the relationship of the first coefficient K1 ≥ the second coefficient K2 is satisfied. Since the second coefficient K2 is a value equal to or less than the first coefficient K1, this relationship should be satisfied when there is no abnormality in the communication between the lens barrel 3 or the camera body 2 and the lens barrel 3.

When this relationship is satisfied (YES in step S3), it is determined that no abnormality has occurred, and in step S4, the camera control unit 21 sets the abnormality flag to 0.

On the other hand, if this relationship is not satisfied (NO in step S3), it is determined that some abnormality has occurred, and in step S5, the camera control unit 21 sets the abnormality flag to 1. When an abnormality occurs, it is highly possible that the current position image plane movement coefficient K _cur is not correctly transmitted to the camera body 2, and the accuracy of the contrast AF processing may decrease. Therefore, the abnormality may be displayed on the camera body 2 or the moving image may not be recorded.

Further, the camera control unit 21 determines whether or not the relationship of the first coefficient K1 ≤ the third coefficient K3 is satisfied in the same manner as the determination of whether or not the relationship of the first coefficient K1 ≥ the second coefficient K2 is satisfied. Is preferable. In the present embodiment, the third coefficient K3 may be a value of the first coefficient K1 or more, and is not particularly limited. Such processing will be described in detail with reference to FIG.

That is, in step S21 shown in FIG. 16, the lens communication unit 38 transmits the first coefficient K1 (current position image plane movement coefficient K _cur ) and the third coefficient K3 to the camera body 2.
In step S22, the camera communication unit 29 of the camera body 2 receives the first coefficient K1 and the third coefficient K3.

In step S23, the camera control unit 21 determines whether or not the relationship of the first coefficient K1 ≦ the third coefficient K3 is satisfied. Since the third coefficient K3 is a value equal to or higher than the first coefficient K1, this relationship should be satisfied when there is no abnormality in the communication between the lens barrel 3 or the camera body 2 and the lens barrel 3.

When this relationship is satisfied (YES in step S23), it is determined that no abnormality has occurred, and in step S24, the camera control unit 21 sets the abnormality flag to 0.

On the other hand, if this relationship is not satisfied (NO in step S23), it is determined that some abnormality has occurred, and in step S25, the camera control unit 21 sets the abnormality flag to 1. When an abnormality occurs, it is highly possible that the current position image plane movement coefficient K _cur is not correctly transmitted to the camera body 2, and the accuracy of the contrast AF processing may decrease. Therefore, it may be possible to display on the camera body 2 that it is abnormal or to disable video recording.

As described above, in the third embodiment, the current position image plane movement coefficient K _cur is set as the first coefficient K1, and the value equal to or less than the current position image plane movement coefficient K _cur is set as the second coefficient K2, from the lens barrel 3 to the camera. Send to the main body 2. Therefore, the camera body 2 can determine the abnormality.

As described above, in the present embodiment, there is no particular limitation as long as the second coefficient K2 is equal to or less than the first coefficient K1. The second coefficient K2 may be, for example, the current position image plane movement coefficient K _cur , the minimum image plane movement coefficient K _min , the current position image plane movement coefficient K _cur, and the minimum image plane movement coefficient K _min.
It may be a value between and, or a value smaller than the minimum image plane movement coefficient K _min . Further, the second coefficient K2 may be a constant value, a value that fluctuates (for example, periodically or regularly), or an arbitrary random value as long as the condition that the first coefficient K1 or less is satisfied. It may be.
Further, the fact that the second coefficient K2 is equal to or less than the first coefficient K1 is compatible with the setting example of the desirable second coefficient K2 of the high-speed search described in the second embodiment.
(Fourth Embodiment)
In the fourth embodiment, it is determined whether or not the camera body 2 uses the second coefficient K2 to reduce the backlash. First, the backlash filling will be explained.

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. Such a drive transmission mechanism includes, for example, a first drive mechanism 500 and a second drive mechanism 600, as shown in FIG. By driving the first drive mechanism 500, the second drive mechanism 600 on the focus lens 33 side is driven. As a result, the focus lens 33 is provided with a configuration for moving the focus lens 33 to the near side or the infinity side. In such a drive mechanism, a backlash amount G is usually provided from the viewpoint of smooth operation of the meshing portion of the gear.

However, on the other hand, in the contrast detection method, due to its mechanism, as shown in FIGS. 18A and 18B, the focus lens 33 is once in focus by a search operation (scan operation, search operation). After passing through, it is necessary to reverse the driving direction and drive to the in-focus position. In this case, if the backlash is not driven as shown in FIG. 18B, the lens position of the focus lens 33 is deviated from the in-focus position by the backlash amount G. Therefore, in order to eliminate the influence of such a backlash amount G, as shown in FIG. 18A, when the focus lens 33 is focused, the driving direction is again after passing the focusing position once. It becomes necessary to perform a backlash-filling drive that reverses and drives the lens to the in-focus position.

FIG. 18 is a diagram showing the relationship between the position of the focus lens 33, the focus evaluation value, and the time when the search operation and the focusing drive based on the contrast detection method according to the present embodiment are performed.

Then, in FIG. 18A, at time t ₀ , the camera control unit 21 starts the search operation of the focus lens 33 from the lens position P0 from the infinity side to the nearest side. Then, at time t ₁ , when the focus lens 33 is moved to the lens position P1, the peak position P2 of the focus evaluation value is detected. At this point, the camera control unit 21 stops the search operation and performs the focusing drive accompanied by the backlash packing drive. As a result, the focus lens 33 is driven to the in-focus position at time t ₂ .

On the other hand, in FIG. 18B, similarly, at time t ₀ , the camera control unit 21 starts the search operation. After that, at time t ₁ , the camera control unit 21 stops the search operation and performs focusing drive without backlash packing drive. Thus, at time t _3, the focus lens 33 is driven to an in-focus position.
In the present embodiment, the camera body 2 uses the second coefficient K2 to perform a backlash filling determination process as to whether or not to perform backlash packing.

FIG. 19 is a sequence diagram showing an example of the backlash filling determination process. The following operations are executed when the focusing position is detected by the contrast detection method. That is, as shown in FIGS. A14 (A) and 18 (B), the time t ₁ at which the peak position P2 of the focus evaluation value was detected.
It is executed at the time of. Further, it is assumed that the backlash amount G of the drive transmission mechanism of the focus lens 33 (see FIG. 17, hereinafter simply referred to as the backlash amount G) is stored in the lens memory 37 in advance.

First, in step S51, the lens communication unit 38 of the lens barrel 3 transmits the second coefficient K2 and the backlash amount G to the camera body 2. The lens communication unit 38 may transmit the second coefficient K2 and the backlash amount G by hotline communication, or may transmit in response to a transmission request from the camera body 2.
In step S52, the camera communication unit 29 of the camera body 2 receives the second coefficient K2 and the backlash amount G.

In step S53, the camera control unit 21 based on the second coefficient K2 and the amount of play G, to calculate the image plane movement amount I _G corresponding to backlash amount G. The image plane movement amount IG corresponding to the backlash amount _G is the movement amount of the image plane when the focus lens 33 is driven by the backlash amount G, and is calculated according to the following formula in the present embodiment.
_IG = G / K2

In step S54, the camera control unit 21, the process of comparing the image plane movement amount I _G corresponding to backlash amount G, and a predetermined image plane movement amount I _P, i.e., the image plane movement amount corresponding to the "amount of play G I _G "≦" whether a predetermined image plane movement amount I _P "is true determination is made.

The predetermined image plane movement amount _IP is set corresponding to the focal depth of the optical system, and is usually set to the image plane movement amount corresponding to the focal depth. Further, since the predetermined image plane movement amount I _P is set to the depth of focus of the optical system, it may be appropriately set according to the F value, the cell size of the image sensor 22, and the format of the image to be captured. Can be. That is, the larger the F value, the larger the predetermined image plane movement amount I _P can be set. 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.

When the image plane movement amount I _G corresponding to backlash amount G is less than or equal to a predetermined image plane movement amount I _P (YES in step S54), without a play reduction drive, the position of the focus lens 33 after driving Can be within the depth of focus of the optical system. Therefore, in step S55, the camera control unit 21 determines that the backlash closing drive is not performed during the focusing drive.

On the other hand, if the image plane movement amount I _G corresponding to backlash amount G is larger than the predetermined image plane movement amount I _P (NO in step S54), unless the play reduction drive, the lens position of the focus lens 33 after driving It cannot be within the depth of focus of the optical system. Therefore, in step S56, the camera control unit 21 determines that the backlash closing drive is performed during the focusing drive.
The camera body 2 transmits the above determination result to the lens barrel 3. Then, focusing is driven according to the determination result.

In the above embodiment, the image plane movement amount I _G when the second coefficient K2 is the current position image plane shift factor K _cur is image plane movement when the second coefficient K2 is a minimum image plane shift factor K _min It becomes smaller than the amount I _G. Therefore, when the lens communication unit 38 transmits the current position image plane movement coefficient K _cur as the second coefficient K2 (when the image plane movement amount _IG is small), the camera control unit 21 sets the minimum image as the second coefficient K2. Compared with the case where the surface movement coefficient K _min is transmitted (when the image plane movement amount _IG is large), the backlash packing drive is less likely to be performed, and the time required for the focusing drive can be shortened by the amount that the backlash packing drive is not performed. On the other hand, the image plane movement amount I _G when the second coefficient K2 is a minimum image plane shift factor K _min, from the image plane movement amount I _G when the second coefficient K2 is the current position image plane shift factor K _cur It will be a large value. Therefore, when the lens communication unit 38 transmits the minimum image plane movement coefficient K _min as the second coefficient K2 (when the image plane movement amount _IG is large), the camera control unit 21 sets the current position image as the second coefficient K2. Compared with the case where the surface movement coefficient K _cur is transmitted (when the image plane movement amount _IG is small), the backlash packing drive is more easily performed, and the focusing accuracy can be guaranteed by the amount of the backlash packing drive. For example, the lens communication unit 38 even if the amount of play has changed (to increase the image plane movement amount I _G) transmitting the minimum image plane shift factor K _min as a second coefficient K2 by aging by, certainly focus Accuracy can be ensured.

FIG. 20 is a diagram schematically showing the relationship between the magnitude of the second coefficient K2 and the focusing accuracy and focusing speed. The smaller the second coefficient K2, the larger the image plane movement amount IG corresponding to the backlash amount G, and it becomes easier to determine that "the backlash is packed". As a result, the smaller the second coefficient K2, the more reliable the focusing accuracy can be guaranteed. On the other hand, as the second coefficient K2 is increased, the image plane movement amount IG corresponding to the backlash amount G becomes smaller, and it becomes easier to determine that "the backlash is not packed". As a result, as the second coefficient K2 is increased, the focusing speed is increased by the amount that the backlash packing drive is not performed, and a good-looking through image can be obtained.

Therefore, the second coefficient K2 may be appropriately set in consideration of the balance between the focusing accuracy and the focusing speed. As an example, when focusing accuracy is important, the second coefficient K2 is set to a small value (for example, the minimum image plane movement coefficient K _min ), and when focusing speed is important, the second coefficient K2 is set to a large value (for example). For example, the current position image plane movement coefficient K _cur ) can be set. Of course, the second coefficient K2 may be a value between the minimum image plane movement coefficient K _min and the current position image plane movement coefficient K _cur , or may be a value smaller than the minimum image plane movement coefficient K _min .

As described above, in the fourth embodiment, the second coefficient K2 is transmitted from the lens barrel 3 to the camera body 2 to determine whether or not the backlash is required. Focusing accuracy can be improved by reducing the backlash. Further, the balance between the focusing accuracy and the focusing speed can be adjusted on the lens barrel 3 side by the value of the second coefficient K2.

For example, in the lens barrel 3, the second coefficient K2 is stored in the lens memory 37 in advance at the time of shipment from the factory. For example, the second coefficient K2 = K _cur may be set in the lens barrel 3 suitable for moving image shooting, and the second coefficient K2 = K _min may be set in the lens barrel 3 suitable for still image shooting. .. This is because the lens barrel 3 suitable for moving image shooting is less likely to be loosely packed in consideration of the appearance of the through image, and the lens barrel 3 suitable for still image shooting is for surely guaranteeing the focusing accuracy. In this way, not only the current image plane movement coefficient K _cur and / or the minimum image plane movement coefficient K _min, but also whether the lens barrel is suitable for moving image shooting or still image shooting is considered. Then, the second coefficient K2 may be set, and as a specific example, the latter second coefficient K2 may be set to a smaller value.

For example, the second coefficient K2 = K _cur is set for the lens barrel 3 in which a high-grade member (gear, etc.) with less wear is used, and the lens barrel 3 in which a member that is easily worn is used. Two coefficients K2 = K _min × 0.5 may be set. This is to ensure the focusing accuracy of the lens barrel 3 in which the gears and the like are easily worn, even if the gears are worn due to long-term use. In this way, the second coefficient K2 is set in consideration of not only the current image plane movement coefficient K _cur and / or the minimum image plane movement coefficient K _min but also the durability of the member used for the lens barrel 3. Also, as a specific example, the second coefficient K2 may be set to a smaller value as a member that is easily consumed is used.

For example, the lens barrel 3 has a calculation unit (not shown) for calculating the period elapsed from the manufacturing date of the lens barrel 3, the usage period of the lens barrel 3, and the like, and the lens control unit 36 has a calculation unit. The longer the calculated period, the smaller the second coefficient K2 may be set. For example, the lens control unit 36 sets the second coefficient K2 = K _min when the period calculated by the calculation unit is 5 years or more, and the second coefficient K2 = K _min +0.3 when the period is less than 5 years and 3 years or more. × (K _cur- K _min ) and the period is less than 3 years 1
When it is more than a year, the second coefficient K2 = K _min +0.6 × (K _cur −K _min ), and when the period is less than one year, the second coefficient K2 = K _cur may be set. This is to ensure the focusing accuracy even when the gears are worn due to long-term use. In this way, the current image plane movement coefficient K _cur
And / or the second coefficient may be determined in consideration of not only the minimum image plane movement coefficient K _min but also the elapsed period from the manufacturing date of the lens barrel 3, and as a specific example, the longer the elapsed period from the manufacturing date, the longer the elapsed period from the manufacturing date. The second coefficient may be a small value.

In the backlash control according to the fourth embodiment described above, the camera control unit 21 may determine the necessity of backlash reduction according to the focal length, the aperture, and the subject distance. Further, the camera control unit 21 may change the drive amount for backlash reduction according to the focal length, the aperture, and the subject distance. For example, when the aperture is stopped down below the predetermined value (when the F value is large), it is not necessary to reduce the backlash as compared with the case where the aperture is not stopped down below the predetermined value (when the F value is small). Judgment or control may be performed so as to reduce the amount of drive for loosening. Further, for example, on the wide side, it may be determined that the backlash packing is unnecessary, or the drive amount of the backlash filling may be smaller than that on the tele side.
(Fifth Embodiment)

In the fifth embodiment, the lens control unit 36 transmits the second coefficient K2 to the camera control unit, and the camera control unit 21 uses the second coefficient K2 to determine whether or not silent control is possible. When the camera control unit 21 permits the silent control, the lens control unit 36 executes the silent control (for example, a clip of the driving speed) if a predetermined condition is satisfied, and the camera control unit 21 does not permit the silent control. An embodiment in which silent control is not executed is described.

The silent control is, for example, controlling the speed so that the driving speed of the focus lens 33 does not become slower than the silent lower limit lens speed (for example, clipping the speed so that the driving speed does not become slower than the silent lower limit lens speed). In some lens barrels, when the driving speed of the focus lens 33 is slower than the silent lower limit lens speed, the driving sound when driving the focus lens 33 becomes louder than a predetermined level, which hinders audio recording during movie shooting. Because it can be.
Hereinafter, it will be described in detail with reference to FIGS. 21 to 23.
FIG. 21 is a sequence diagram showing an example of determination by the camera control unit 21 whether or not silent control is possible.
In step S60, the camera control unit 21 sets the focus detection image plane moving speed V1a_img (mm / sec).

Focus detection image plane moving speed V1a_img is an image plane moving speed capable of detecting the focus with a predetermined accuracy. Focus detection The focus can be detected with a predetermined accuracy by performing a search operation (search operation) at a search speed of V1a_img or less and detecting the peak position of the focus evaluation value. On the other hand, when the search operation is performed at a search speed faster than the focus detection image plane moving speed V1a_img and the peak position of the focus evaluation value is detected, the focus detection accuracy may not reach a predetermined accuracy.

Therefore, it is preferable that the camera control unit 21 transmits the drive instruction speed to the lens control unit 36 so that the image plane moving speed becomes the focus detection image plane moving speed V1a_img or less when performing the search operation.

For example, regarding the second search speed of the second embodiment described above, the camera control unit 21 sets the image plane moving speed to be faster than the focus detection image plane moving speed V1a_img, and sets the second search speed of the second embodiment described above. Regarding the 1-search speed and the 3rd search speed, the image plane moving speed may be set to be equal to or lower than the focal detection image plane moving speed V1a_img.

The focus detection image plane moving speed V1a_img may differ depending on, for example, the frame rate, the calculation method of the peak position of the focus evaluation value, and the like. The focus detection image plane moving speed V1a_img is set for each type of the camera body 2, for example, and is stored in the camera memory 24 at the time of shipment from the factory.

The search speed is determined by various conditions, and may differ depending on whether the search control is started with a half-press of the release switch as a trigger or the search control is performed with another condition as a trigger, and is a still image shooting mode. It may also differ depending on whether it is in the moving image shooting mode, or it may differ depending on the frame rate, focal length, shooting distance, aperture value, and the like.

In step S61, before the contrast AF search operation is started, the lens control unit 36 sets the silent lower limit lens speed V0b_ls (pulse / sec) and the second coefficient K2 via the lens communication unit 39 and the camera communication unit 39. It is transmitted to the camera control unit 21. The silent lower limit lens speed V0b_lns is the driving speed of the lower limit focus lens 33 at which the driving sound when driving the focus lens 33 is less than a predetermined level. The silent lower limit lens speed V0b_lns is stored in the lens memory 37 at the time of shipment from the factory, for example.
In step S62, the camera control unit 21 receives the silent lower limit lens speed V0b_ls and the second coefficient K2 from the lens control unit 36.

In step S63, the camera control unit 21 converts the silent lower limit lens speed V0b_lns (pulse / sec) into the silent lower limit image plane moving speed V0b_img (mm / sec) using the second coefficient K2. More specifically, the camera control unit 21 calculates the silent lower limit image plane moving speed V0b_img based on the following equation.
V0b_img = V0b_lns / K2

For example, when the second coefficient K2 is the minimum image plane movement coefficient Kmin, the silent lower limit image plane movement speed V0b_img is such that the lens speed of the focus lens 33 is the silent lower limit lens speed V0b_lns at the position where the image plane movement coefficient is the minimum value. Corresponds to the image plane movement speed.
In step S64, the camera control unit 21 determines whether or not the following equation (4) is satisfied.
V1a_img * B ≧ V0b_img = V0b_lns / K2 (however, 1 ≦ B)
... (4)

As described above, the focus detection image plane moving speed V1a_img is set to a value at which the focus can be detected with a predetermined accuracy. The camera control unit 21 increases the coefficient B as the aperture value increases, or when the image size is small such as a live view image (when the image compression rate is high or the pixel data thinning rate is high). Since high focus detection accuracy is not required, the coefficient B may be increased, or the coefficient B may be increased when the pixel pitch of the image sensor is wide. Live view is, for example, a function that displays a subject on a monitor at the time of shooting and allows the photographer to shoot while checking the subject.

When the above equation (4) is satisfied (YES in step S64), in step S65, the camera control unit 21 permits the clipping operation at, for example, the silent lower limit lens speed V0b_ls.

For example, when the second coefficient K2 is the minimum image plane movement coefficient Kmin and the above equation (4) is satisfied, the lens speed of the focus lens 33 is the silent lower limit lens speed V0b_ls at the position where the image plane movement coefficient is the minimum value. This means that the image plane moving speed is V1a_img * B or less, and the focus can be detected with a predetermined accuracy even if the clipping operation is performed at the silent lower limit lens speed V0b_ls.
On the other hand, if the above equation (4) is not satisfied (NO in step S65), the camera control unit 21 prohibits the clip operation in step S66.

For example, when the second coefficient K2 is the minimum image plane movement coefficient Kmin and the above equation (4) is not satisfied, the lens speed of the focus lens 33 is the silent lower limit lens speed at the position where the image plane movement coefficient is the minimum value. It means that the image plane movement speed of V0b_ls is larger than V1a_img * B. For example, when the clip operation is performed at the quiet lower limit lens speed V0b_ls at the position where the image plane movement coefficient is the minimum value, the focus is detected with a predetermined accuracy. This is because there is a possibility that it cannot be done.

In steps S67 and S68, the camera control unit 21 determines whether to allow or prohibit the clip operation via the camera communication unit 29 and the lens communication unit 39, and determines the drive instruction lens speed (search speed) of the lens barrel. It is transmitted to the lens control unit 36 of 3. As the search speed, for example, it is preferable to transmit at the lens speed (pulse / sec) instead of the image plane moving speed (mm / sec).
FIG. 22 is a flowchart showing an example of the processing operation of the lens barrel 3 when the camera control unit determines that the silent control is permitted.
In step S71, the lens control unit 36 acquires the silent lower limit lens speed V0b_ls stored in the lens memory 37.

In step S72, the lens control unit 36 receives the drive instruction lens speed (search speed) Vdrc_ls (pulse / sec) from the camera control unit 21 via the lens communication unit 39 and the camera communication unit 39.

The drive instruction lens speed Vdrc_lns is, for example, a speed that is slower than the focus detection image plane movement speed V1a_img and the image plane movement speed becomes constant. The camera control unit 21 sets the conditions, shooting settings, and the like.
In step S73, the lens control unit 36 compares the drive instruction lens speed Vdrc_ls with the silent lower limit lens speed V0b_ls.

When the drive instruction lens speed Vdrc_ls is smaller than the silent lower limit lens speed V0b_ls (YES in step S73), in step S74, the lens control unit 36 drives the focus lens 33 at the silent lower limit lens speed V0b_ls instead of the drive instruction lens speed Vdrc_ls (YES in step S73). Search operation (search operation). If the focus lens 33 is driven at the drive instruction lens speed Vdrc_lss, the focus lens 33 will be driven at a drive speed less than the silent lower limit lens speed V0b_lss, and the drive sound when driving the focus lens 33 will be louder than a predetermined level. is there. Since silent control (clip operation) is permitted, the focus can be detected with a predetermined accuracy even if the driving speed is clipped at the silent lower limit lens speed V0b_lns. However, it is compared with the case where the search operation is performed so that the moving speed of the image plane becomes constant by clipping the drive speed with the silent lower limit lens speed V0b_lns so that the speed of the focus lens 33 becomes constant. As a result, the focus detection accuracy may deteriorate.

On the other hand, when the drive instruction lens speed Vdrc_ls is equal to or higher than the silent lower limit lens speed V0b_ls (NO in step S73), in step S75, the lens control unit 36 drives the focus lens 33 at the drive instruction lens speed Vdrc_ls (search operation (search operation). )). This is because no noise is generated even if the lens is driven at the drive instruction lens speed Vdrc_lns.

As described above, in the present embodiment, the camera control unit determines the permission for the silent control. Therefore, if the permission is made, the focus lens 33 is driven based on the determination (step S73) of the lens control unit 36. By clipping the speed at the silent lower limit lens speed V0b_lns, it is possible to suppress the generation of driving noise above a predetermined level. Further, when the silent control is prohibited by the camera control unit, the focus can be detected with a predetermined accuracy by not clipping based on the determination of the lens control unit 36 (step S73).

Further, by performing the search operation so that the moving speed of the image plane becomes constant, improvement in the focus detection accuracy can be expected as compared with the case where the search operation is performed so that the speed of the focus lens 33 becomes constant.

Here, when the second coefficient K2 is the current position image plane movement coefficient Kcur, the camera control unit 21 determines permission for silent control as compared with the case where the second coefficient K2 is the minimum image plane movement coefficient Kmin. This facilitates the process, and the drive speed of the focus lens 33 is easily clipped based on the determination of the lens control unit 36 (step S73), so that more reliable silent control can be expected. Therefore, for example, the lens barrel 3 suitable for moving image shooting has a second coefficient K2 = K _cur stored in the lens memory 37 at the time of shipment from the factory, and the lens barrel suitable for still image shooting has a second coefficient K2 = K _min. May be configured to be stored in the lens memory 37 at the time of shipment from the factory.

FIG. 23 is a diagram schematically showing the relationship between the magnitude of the second coefficient K2 and the quietness and focusing accuracy. As is clear from the above equation (4), the smaller the second coefficient K2, the easier it is for the clip operation to be prohibited. As a result, the smaller the second coefficient K2, the more difficult the clipping operation becomes, and the improvement in focusing accuracy can be expected. On the other hand, the larger the second coefficient K2, the easier it is for the clip operation to be permitted. As a result, as the second coefficient K2 is increased, the clipping operation becomes easier and the quietness is improved.

Therefore, the second coefficient K2 may be appropriately set in consideration of the balance between quietness and focusing accuracy. As an example, when focusing accuracy is important, the second coefficient K2 is set to a small value (for example, the minimum image plane movement coefficient K _min ), and when quietness is important, the second coefficient K2 is set to a large value (for example). The current position image plane movement coefficient K _cur ) can be set. Of course, the second coefficient K2 may be a value between the minimum image plane movement coefficient K _min and the current position image plane movement coefficient K _cur , or may be a value smaller than the minimum image plane movement coefficient K _min .

As described above, in the fifth embodiment, the lens control unit 36 transmits the second coefficient K2, and the camera control unit 21 determines whether to allow or prohibit the silent control (clip operation). The lens control unit 36 can suppress the driving sound of the focus lens to less than a predetermined level by performing a clipping operation if a predetermined condition is satisfied when the camera control unit 21 permits silent control. Further, the balance between quietness and focusing accuracy can be adjusted on the lens barrel 3 side by the value of the second coefficient K2.
(Sixth Embodiment)

In the sixth embodiment, a single-lens reflex digital camera including a lens barrel 3 provided with a focus limit switch and a camera body 2 will be described. The focus limit switch is a switch that can be operated by the user to set the driveable range of the focus lens 33. By operating the focus limit switch to select the focus limit mode, the focus lens 33 can be driven within the driveable range desired by the user.

FIG. 24 is a diagram showing a drive range of the focus lens 33. As shown in the figure, the focus lens 33 is configured to be movable toward the infinity direction 410 and the near direction 420 on the optical axis L1 indicated by the alternate long and short dash line in the figure. A stopper (not shown) is provided at the mechanical end point (mechanical end point) 430 in the infinity direction 410 and the mechanical end point 440 in the near direction 420 to mechanically restrict the movement of the focus lens 33. That is, the focus lens 33 is configured to be movable from the mechanical end point 430 in the infinity direction 410 to the mechanical end point 440 in the close direction 420.

However, the range in which the lens control unit 36 actually drives the focus lens 33 is a range from the infinite soft limit position 450 to the nearest soft limit position 460, which is narrower than the range from the mechanical end point 430 to the mechanical end point 440 described above. Is. The infinite soft limit position 450 and the close-up soft limit position 460 are for electrically limiting the movement of the focus lens 33. Specifically describing this movement range, the lens control unit 36 is inside the infinite soft limit position 450 provided inside the mechanical end point 430 of the infinity direction 410 and inside the mechanical end point 440 of the closest direction 420. The focus lens 33 is driven in the range up to the provided near soft limit position 460. That is, the lens drive unit 212 drives the focus lens 33 between the close soft limit position 460 corresponding to the drive limit position on the close side and the infinite soft limit position 450 corresponding to the drive limit position on the infinity side.

The infinite soft limit position 450 is provided outside the infinite focusing position 470. The infinite focusing 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 aperture 35 can be focused. The reason why the infinite soft limit position 450 is provided at such a position is that a peak of the focus evaluation value may exist at the infinite focus position 470 when the focus is detected by the contrast detection method. That is, if the infinite focusing 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 focusing position 470 cannot be recognized as a peak. The infinite soft limit position 450 is provided outside the infinite focusing position 470 in order to avoid the above.

Similarly, the closest soft limit position 460 is provided outside the closest focusing position 480. Here, the closest focusing 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 aperture 35 can be focused.

As described above, the range in which the lens control unit 36 drives and controls the focus lens 33 is a range from the infinite soft limit position 450 to the nearest soft limit position 460.

The close focus position 480 can be set by using, for example, aberration or the like. For example, even if the focus lens 33 can be focused by driving the focus lens 33 closer to the set close focus position 480, if the aberration worsens, it is not appropriate as the lens usage range. Because there isn't.

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 by the lens control unit 36 to the lens drive motor 321. In this case, the number of pulses is the infinite focusing position 470. It can be the origin (reference). For example, in the example shown in FIG. 5, the infinite soft limit position 450 is the position of "-100 pulses", the close focus position 480 is the position of "9800 pulses", and the close soft limit position 460 is the position of "9900 pulses". .. In this case, in order to move the focus lens 33 from the infinite soft limit position 450 to the nearest soft limit position 460, it is necessary to give a drive signal for 10,000 pulses to the lens drive motor 321. However, the present embodiment is not particularly limited to such an embodiment.

FIG. 25 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. Further, FIG. 26 is a diagram showing the relationship between the drive range of the focus lens 33 and the position of the focus lens 33. In this embodiment, an example will be described in which the image plane movement coefficient becomes smaller as the position of the focus lens 33 becomes closer.

As shown in FIG. 25, the image plane movement coefficient K is also defined outside the drive control range of the focus lens 33 by the lens control unit 36. That is, as shown in FIG. 26, the region including the close focus position 480 corresponds to the shooting distance D1, and the region including the close soft limit position 460 is photographed on the outside (closest mechanical end point 440 side). The area including the closest mechanical end point 440 corresponds to the shooting distance X2 at the distance D0, and the area further close to the shooting distance X1 corresponds to the shooting distance X1. Similarly, the area including the infinite focusing position 470 corresponds to the shooting distance D9, and the area including the infinite soft limit position 450 corresponds to the shooting distance D10 on the outside (infinite mechanical end point 430 side). The region including the target end point 430 corresponds to the shooting distance X3, and the region on the infinite side corresponds to the shooting distance X4. Then, the image plane movement coefficient K at each of the photographing distances X1 to X4, D0 to D10 and the focal lengths f1 to f9 is included in the table.

For example, the values of the image plane movement coefficients “α11”, “α21”, ... “Α91” in the shooting distance “X1” are the image plane movement coefficients “K10”, “K20”, in the shooting distance “D0” region.・ ・ It is smaller than the value of “K90”. Similarly, the values of the image plane movement coefficients "α12", "α22", ... "Α92" at the shooting distance "X2" are the image plane movement coefficients "K10", "K20", ...・ ・ It is smaller than the value of “K90”. Further, the values of the image plane movement coefficients "α13", "α23", ... "α93" at the shooting distance "X3" are the image plane movement coefficients "K110", "K210" at the shooting distance "D10", ... -It is larger than the value of "K910". The values of the image plane movement coefficients "α14", "α24", ... "Α94" at the shooting distance "X4" are the image plane movement coefficients "K110", "K210", ... "" at the shooting distance "D10". It is larger than the value of "K910".

In this case, the minimum image plane movement coefficient K _min is the image plane movement coefficient K in “X1” (“α”).
11 ”,“ α21 ”, ・ ・ ・“ α91 ”)), or the image plane movement coefficient K (“α12”, “α22”, ・ ・ ・ “α92”) in “X2” may be used. The image plane movement coefficient K (“K10”, “K20” ... “K90”) at “D0” may be used. The maximum image plane movement coefficient K _max is the image plane movement coefficient K (“α14”, “α24”, “α24” in “X4”,
... "α94")), the image plane movement coefficient K ("α13", "α23", ... "α93") at "X3", or the image plane movement at "D10". The coefficient K (“K110”, “K210” ... “K910”) may be used.

FIG. 27 is a diagram showing an example of a driveable range (focus limit mode) set by the user operating a focus limit switch (not shown). In the search operation in the contrast AF, the range in which the lens control unit 36 does not detect the peak of the focus evaluation value is shown in gray. In the present embodiment, as shown in FIGS. 27 (A) to 27 (C), the user operates the focus limit switch to perform "FULL mode", "closest side restriction mode", and "infinity side restriction mode". "Three focus limit modes can be set.

The "FULL mode" is a mode for detecting the peak of the focus evaluation value within the range from the infinity end soft limit SL _IP to the nearest end soft limit SL _NP in the contrast AF search operation (search operation). As shown in 27 (A), the range from the lens position of the infinity end soft limit SL _{IP to} the lens position of the nearest end soft limit SL _NP is set as the driveable range Rf1 in the search operation (search operation). Will be done.

Further, the "closest side limit mode" is a mode for detecting the peak of the focus evaluation value in the range from the infinity end soft limit SL _IP to the nearest side soft limit SL _NS in the search operation of the contrast AF. As shown in B), the range from the lens position of the infinity end soft limit SL _{IP to} the lens position of the nearest soft limit SL _NS is set as the driveable range Rf2 in the search operation.

Further, the "infinity side limit mode" is a mode in which the peak of the focus evaluation value is detected in the range from the infinity side soft limit SL _IS to the nearest end soft limit SL _NP in the contrast AF search operation. As shown in 26 (C), the range from the lens position of the infinity side soft limit SL _{IS to} the lens position of the nearest soft limit SL _NP is set as the driveable range Rf3 in the search operation.

The user can set the driveable range to "FULL mode", "closest side limiting mode", or "infinity side limiting mode" by using, for example, a focus limit switch (not shown) provided on the outside of the lens barrel 3. ..

The operation of the lens barrel 3 will be described with reference to FIGS. 25 and 27. In the following description, the minimum image plane movement coefficient K _min is the image plane movement coefficient K (“K10”, “K20” at “D0” shown in FIG. 25.
"..." K90 "), and the maximum image plane movement coefficient K _max is shown in FIG. 25," D10 ".
The operation will be described by taking as an example the case where the image plane movement coefficient K (“K110”, “K210” ... “K910”) in the above is set.

First, a case where contrast AF is performed when the user sets the “FULL mode” shown in FIG. 27 (A) will be described. In this case, the lens control unit 36 performs the above-mentioned initial drive, search drive, and focusing drive. When the camera control unit 21 requests transmission of the first coefficient K1, the second coefficient K2, and the third coefficient K3 (see step 104 in FIG. 7), the lens control unit 36 sets the current position image plane as the first coefficient K1. Movement coefficient K _cur (current position image plane movement coefficient of focus lens 33), minimum image plane movement coefficient K _min (for example, K30) as the second coefficient K2, maximum image plane movement coefficient K _max (for example, K310) as the third coefficient K3. To send.
Next, a case where the user sets the "closest side restriction mode" shown in FIG. 27B will be described. For example, assume that the nearest soft limit SL _NS is D5.

For example, when the position of the focus lens 33 when the contrast AF is started is D7 (the region where the peak of the focus evaluation value is detected), the lens control unit 36 performs the above-mentioned initial drive, search drive, and focus drive. In, the focus lens 33 is driven and controlled within the region where the peak of the focus evaluation value is detected. Further, in response to the request of the camera control unit 21, the current position image plane movement coefficient K _cur (current position image plane movement coefficient of the focus lens 33) and the second coefficient K1 are set as the first coefficient K1.
The image plane movement coefficient (for example, K35) corresponding to the position D5 is transmitted as the coefficient K2, and the maximum image plane movement coefficient K _max (for example, K310) is transmitted as the third coefficient K3. Since the focus lens 33 is driven and controlled within the region where the peak of the focus evaluation value is detected, the second coefficient K2 is the minimum image plane movement coefficient K _min corresponding to the position D0 outside the region where the peak of the focus evaluation value is detected. This is because more preferable control can be performed by using the image plane movement coefficient (for example, K35) corresponding to the position D5 of the nearest soft limit SL _NS rather than using.

On the other hand, for example, when the position of the focus lens 33 when the contrast AF is started is D3 (the region where the peak of the focus evaluation value shown in gray in FIG. 27 (B) is not detected), the lens control unit 36 First, the focus lens 33 is driven to the infinite end side. As a result, the position of the focus lens 33 changes to D3, D4, and D5. When the camera control unit 21 requests transmission of the second coefficient K2 when the position of the focus lens 33 is D3, the lens control unit 36 transmits the image plane movement coefficient (for example, K33) corresponding to the position D3. When a transmission request for the second coefficient K2 is made when the position of the focus lens 33 is D4, the lens control unit 36 transmits an image plane movement coefficient (for example, K34) corresponding to the position D4. This is because the image plane movement coefficient corresponding to the positions D3 and D4 is smaller than the image plane movement coefficient corresponding to the position D5 of the nearest soft limit SL _NS . When the positions of the focus lens 33 are D3 and D4, the current position image plane movement coefficient K _cur (current position image plane movement coefficient of the focus lens 33) is used as the first coefficient K1, and the maximum image plane movement coefficient is used as the third coefficient K3. K _max (eg K310) is transmitted.

After that, after the focus lens 33 reaches the position D5, the lens control unit 36 drives and controls the focus lens 33 within the region where the peak of the focus evaluation value is detected in the initial drive, the search drive, and the focus drive. At this time, the lens control unit 36 sets the current position image plane movement coefficient K _cur (current position image plane movement coefficient of the focus lens 33) and the second coefficient K2 as the first coefficient K1 in response to the request of the camera control unit 21. The maximum image plane movement coefficient K _max (for example, K310) is transmitted as the image plane movement coefficient (for example, K35) corresponding to the position D5 and the third coefficient K3.
Next, a case where the user sets the "infinity side restriction mode" shown in FIG. 27C will be described. For example, assume that the infinity soft limit SL _IS is D7.

For example, when the position of the focus lens 33 when the contrast AF is started is D9 (the region where the peak of the focus evaluation value shown in gray in FIG. 27C is not detected), the lens control unit 36 first determines the focus lens. The 33 is driven to the nearest end side. As a result, the position of the focus lens 33 changes from D9 to D7. When the camera control unit 21 requests transmission of the third coefficient K3 when the positions of the focus lens 33 are D9 and D8, the lens control unit 36 transmits the image plane movement coefficient corresponding to the positions D9 and D8. At this time, the lens control unit 36 transmits the current position image plane movement coefficient K _cur as the first coefficient K1 and the minimum image plane movement coefficient K _min as the second coefficient K2 in response to the request of the camera control unit 21.

After that, when the focus lens 33 reaches the position D5, and when the position of the focus lens 33 is a region for detecting the peak of the focus evaluation value from the time when the contrast AF is started, the lens control unit 36 is initially driven. The focus lens 33 is driven and controlled within the region where the peak of the focus evaluation value is detected in the search drive and the focusing drive, and the lens control unit 36 sets the current position image plane as the first coefficient K1 in response to the request of the camera control unit 21. Movement coefficient K _cur , second coefficient K
The minimum image plane movement coefficient K _min is transmitted as 2, and the image plane movement coefficient (for example, K37) corresponding to the position D7 is transmitted to the camera control unit 21 as the third coefficient K3.

Also in this embodiment, the lens control unit 36 can appropriately set the first coefficient K1, the second coefficient K2, and the third coefficient K3, so that the camera control unit 21 has the first coefficient K1, the second coefficient K2, and the third coefficient K3. By controlling using at least one of the above, various controls can be performed according to the characteristics of the lens barrel, the state of use, and the like.

As described above, in the present embodiment, the current position image plane movement coefficient K _cur is transmitted from the lens barrel 3 to the camera body 2 as the first coefficient K1. As a result, the camera body 2 can perform contrast AF processing with high accuracy.

Further, in the present embodiment, a value of the first coefficient K1 or less as the second coefficient K2 is transmitted from the lens barrel 3 to the camera body 2. As a result, the camera body 2 can perform high-speed search determination, abnormality determination, backlash packing determination, and / or clip operation determination. By adjusting the value of the second coefficient K2, the balance of a plurality of performances, which is a trade-off, can be adjusted on the lens barrel 3 side.

The camera body 2 may perform all of the high-speed search determination, the abnormality determination, the backlash packing determination, and the clip operation determination using the second coefficient K2, or at least a part of the determination may be performed.

If the position of the focus lens 33 corresponding to the minimum image plane movement coefficient K _min is closer to the position of the focus lens 33 corresponding to the maximum image plane movement coefficient K _max , the minimum image plane movement coefficient K _min is set. The position of the corresponding focus lens 33 may be, for example, a close focus position, a close soft limit position, a close mechanical end point, or a close focus position. The position may be between the closest mechanical end points, or may be a position closer to the nearest mechanical end point, and the position of the focus lens 33 corresponding to the maximum image plane movement coefficient K _max is, for example, an infinity focusing position. It may be an infinity soft limit position, it may be an infinity mechanical endpoint, it may be a position between the infinity focusing position and the infinity mechanical endpoint, and it may be. The position may be on the infinity side of the infinity mechanical end point.

Similarly, when the position of the focus lens 33 corresponding to the minimum image plane movement coefficient K _min is on the infinity side from the position of the focus lens 33 corresponding to the maximum image plane movement coefficient K _max , the minimum image plane movement coefficient K The position of the focus lens 33 corresponding to _min may be, for example, an infinity focusing position, an infinity soft limit position, an infinity mechanical end point, or the like. It may be a position between the infinity focusing position and the infinity mechanical end point, or it may be a position on the infinity side of the infinity mechanical end point, and as the position of the focus lens 33 corresponding to the maximum image plane movement coefficient K _max. May be, for example, a close focus position, a close soft limit position, a close mechanical end point, or a position between the close focus position and the close mechanical end point. It may be a position closer to the nearest mechanical end point.

Similarly, the maximum image plane movement coefficient K _max may be, for example, an infinity focusing position (closest focusing position), an infinity soft limit position (closest soft limit position), or the like. It may be an infinity mechanical end point (closest mechanical end point), it may be a position between the infinity focusing position (closest focusing position) and the infinity mechanical end point (closest mechanical end point), or it may be infinite. The position may be on the infinity side (closest side) from the far mechanical end point (closest mechanical end point).

It should be noted that the embodiments described above are described for facilitating the understanding of the present invention, and are 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. In addition, each of the above-described embodiments can be used in combination as appropriate.

1 Single-lens reflex digital camera 2 Camera body 21 Camera control unit 29 Camera communication unit 3 Lens lens barrel 32 Zoom lens 33 Focus lens 36 Lens control unit 37 Lens memory 39 Lens communication unit

Claims (15)

An interchangeable lens that can be attached to the camera body
An optical system with a lens that can move in the optical axis direction,
A first value determined according to the position of the lens on the optical axis and showing the relationship between the amount of movement of the lens and the amount of movement of the image formed by the optical system, and a second value equal to the first value. An interchangeable lens including a transmission unit that transmits a value to the camera body. The interchangeable lens according to claim 1.
The transmitting unit is an interchangeable lens characterized in that a third value equal to or higher than the first value is transmitted to the camera body. The interchangeable lens according to claim 2.
The transmitting unit is an interchangeable lens characterized in that the third value is transmitted to the camera body in accordance with the second value. The interchangeable lens according to any one of claims 1 to 3.
The transmitting unit is an interchangeable lens characterized by transmitting a second value equal to the first value regardless of the position of the lens. The interchangeable lens according to any one of claims 1 to 4.
The first value output by the transmitter at the first time is different from the first value output by the transmitter at a second time different from the first time.
The first value and the second value output by the transmitter at the first time are equal to each other.
The first value and the second value output by the transmitter at the second time are equal to each other.
An interchangeable lens that is characterized by that. The interchangeable lens according to any one of claims 1 to 5.
It has a detection unit that detects the position of the lens on the optical axis.
The first value indicating the relationship between the amount of movement of the lens and the amount of movement of the image formed by the optical system at the position on the optical axis of the lens detected by the detection unit. An interchangeable lens characterized by transmitting the image to the camera body. The interchangeable lens according to any one of claims 1 to 6.
When the photographer performs a live view shooting operation, the transmission unit transmits the second value to the camera body, and before the live view shooting operation is performed, the second value is transmitted to the camera. An interchangeable lens that does not transmit to the main body. The interchangeable lens according to any one of claims 1 to 7.
The transmission unit is an interchangeable lens that starts transmitting the second value before the search drive of the focal optical system in contrast AF is started. The interchangeable lens according to any one of claims 1 to 8.
It has a receiving unit that receives a request signal from the camera body.
The transmitting unit is an interchangeable lens characterized in that when the receiving unit receives the request signal, the second value is transmitted to the camera body. The interchangeable lens according to any one of claims 2 to 9, which cites claim 2.
It has a receiving unit that receives a request signal from the camera body.
The transmitting unit is an interchangeable lens characterized in that when the receiving unit receives the request signal, the second value and the third value are transmitted to the camera body. The interchangeable lens according to claim 9 or 10.
The receiving unit repeatedly receives the request signal from the camera body, and receives the request signal repeatedly.
The transmitting unit is an interchangeable lens characterized in that each time the receiving unit receives the request signal, the second value is repeatedly transmitted to the camera body. The interchangeable lens according to any one of claims 1 to 11.
The first value is an interchangeable lens characterized by indicating the ratio of the amount of movement of the image plane formed by the optical system to the amount of movement of the lens. The interchangeable lens according to any one of claims 1 to 11.
The first value is an interchangeable lens characterized by indicating the ratio of the movement amount of the lens to the movement amount of the image plane formed by the optical system. A camera body to which the interchangeable lens according to any one of claims 1 to 13 can be attached and detached. The interchangeable lens according to any one of claims 1 to 13 and
A camera comprising the camera body according to claim 14.

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