JP2010107714A - Camera system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera system for relatively easily detecting the peak of a contrast value regardless of the value of a distance between an infinity end and the end of the range where a focus lens is physically movable. <P>SOLUTION: The camera system has an interchangeable lens and a camera body. The interchangeable lens includes: a focus lens; a drive means for driving the focus lens; and a storage means for storing specific information where infinity margin which is the distance between the end of the movable range of the focus lens and the infinity end can be specified. The camera body includes: an acquisition means for acquiring the specific information from the interchangeable lens; a generation means for generating a control signal which makes the drive means drive the focus lens at an arbitrary speed according to the infinity margin that can be specified from the specific information acquired by the acquisition means; and a notification means for notifying the interchangeable lens of the control signal generated by the generating means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a camera system including a camera body and an interchangeable lens, and more particularly to a camera system capable of autofocusing by a contrast method.

  Patent Document 1 discloses an interchangeable lens camera capable of autofocus. The interchangeable lens of this interchangeable lens camera stores duty factors such as a power focus duty factor for high speed driving and a power focus duty factor for low speed driving. The camera body of the interchangeable lens camera reads the duty factor from the interchangeable lens.

Thus, the interchangeable lens camera can finely change the lens driving speed for each type of interchangeable lens mounted.
JP-A 63-70834

  However, the interchangeable lens camera disclosed in Patent Document 1 is premised on phase difference detection type autofocus control. Here, when performing contrast autofocus control, there is a problem that it may be difficult to detect the peak of the contrast value depending on the distance between the infinite end and the end of the range in which the focus lens is physically movable. is there.

  Therefore, the present invention provides a camera system that is relatively easy to detect the peak of the contrast value regardless of the distance between the infinite end and the end of the range in which the focus lens is physically movable. Objective.

  In order to solve the above problems, a camera system according to the present invention is a camera system including an interchangeable lens and a camera body, and the interchangeable lens includes a focus lens, a drive unit that drives the focus lens, and a drive unit. Autofocus control means for performing autofocus by controlling, and the distance between the end of the movable range of the focus lens and the end on the infinite side where the autofocus control means can detect the in-focus position Storage means for storing specific information capable of specifying the margin, and the camera body according to the acquisition means for acquiring the specific information from the interchangeable lens and the infinite margin that can be specified from the specific information acquired by the acquisition means Generating means for generating a control signal for causing the driving means to drive the focus lens at an arbitrary speed; and The made control signals and a notification means for notifying the interchangeable lens.

  According to the present invention, it is possible to provide a camera system that is relatively easy to detect the peak of the contrast value regardless of the distance between the infinite end and the end of the range in which the focus lens is physically movable. it can.

[1. Embodiment 1]
[1-1. Overview〕
A camera system 1 according to the present embodiment includes a camera body 100 and an interchangeable lens 200. Various corresponding interchangeable lenses can be attached to the camera body 100. Depending on the interchangeable lens, the distance between the end of the physical movable range of the focus lens and the infinite end varies.

  The present invention has been made to provide a camera system that is relatively easy to detect the peak of the contrast value regardless of the distance between the infinite end and the end of the range in which the focus lens is physically movable. It is an invention.

[1-2. Constitution〕
[1-2-1. Configuration of camera body)
The camera body 100 includes a CCD image sensor 110, a liquid crystal monitor 120, a camera controller 140, a body mount 150, a power source 160, and a card slot 170.

  The camera controller 140 controls the entire camera system 1 such as the CCD image sensor 110 in response to an instruction from an operation member such as the release button 130. The camera controller 140 transmits a vertical synchronization signal to the timing generator 112. The camera controller 140 uses the DRAM 141 as a work memory during the control operation and the image processing operation. The flash memory 142 stores programs and parameters used when the camera controller 140 is controlled.

  The CCD image sensor 110 captures a subject image incident through the interchangeable lens 200 and generates image data. The generated image data is digitized by the AD converter 111. The image data digitized by the AD converter 111 is subjected to various image processing by the camera controller 140. The various image processes referred to here include, for example, an image compression process such as a gamma correction process, a white balance correction process, a scratch correction process, a YC conversion process, an electronic zoom process, and a JPEG compression process.

  The CCD image sensor 110 operates at a timing controlled by the timing generator 112. The operation of the CCD image sensor 110 includes a still image capturing operation, a moving image capturing operation, a through image capturing operation, and the like. Here, the through image is an image that is not recorded on the memory card 171 after image capturing. The through image is mainly a moving image, and is displayed on the liquid crystal monitor 120 in order to determine a composition for capturing a still image.

  The liquid crystal monitor 120 displays an image indicated by the display image data image-processed by the camera controller 140. The liquid crystal monitor 120 can selectively display both moving images and still images.

  The card slot 170 can be loaded with a memory card 171. The card slot 170 controls the memory card 171 based on the control from the camera controller 140. The memory card 171 can store image data generated by image processing of the camera controller 140. For example, the memory card 171 can store a JPEG image file. The memory card 171 can output image data or an image file stored therein. The image data or image file output from the memory card 171 is subjected to image processing by the camera controller 140. For example, the camera controller 140 expands the image data or image file acquired from the memory card 171 and generates display image data.

  The power supply 160 supplies power for consumption by the camera system 1. The power source 160 may be, for example, a dry battery or a rechargeable battery. Moreover, the power supplied from the outside by the power cord may be supplied to the camera system 1.

  The body mount 150 can be mechanically and electrically connected to the lens mount 250 of the interchangeable lens 200. The body mount 150 can send and receive commands and data to and from the interchangeable lens 200 via the lens mount 250. The body mount 150 transmits various control signals received from the camera controller 140 to the lens controller 240 via the lens mount 250. The body mount 150 supplies the power received from the power supply 160 to the entire interchangeable lens 200 via the lens mount 250.

[1-2-2. Interchangeable lens configuration)
The interchangeable lens 200 includes an optical system, a lens controller 240, and a lens mount 250. The optical system of the interchangeable lens 200 includes a zoom lens 210, an OIS lens 220, a diaphragm 260, and a focus lens 230.

  The zoom lens 210 is a lens for changing the magnification of a subject image formed by the optical system of the interchangeable lens 200. The zoom lens 210 is composed of one or a plurality of lenses. The drive mechanism 211 includes a zoom ring or the like that can be operated by the user, transmits the operation by the user to the zoom lens 210, and moves the zoom lens 210 along the optical axis direction of the optical system. The detector 212 detects the drive amount in the drive mechanism 211. The lens controller 240 can grasp the zoom magnification in the optical system by acquiring the detection result in the detector 212.

  The OIS lens 220 is a lens for correcting blurring of a subject image formed by the optical system of the interchangeable lens 200. The OIS lens 220 moves in a direction that cancels out the blur of the camera system 1, thereby reducing the blur of the subject image on the CCD image sensor 110. The OIS lens 220 is composed of one or a plurality of lenses. The actuator 221 drives the OIS lens 220 in a plane perpendicular to the optical axis of the optical system under the control of the OIS IC 223. The actuator 221 can be realized by a magnet and a flat coil, for example. The position detection sensor 222 is a sensor that detects the position of the OIS lens 220 in a plane perpendicular to the optical axis of the optical system. The position detection sensor 222 can be realized by a magnet and a Hall element, for example. The OIS IC 223 controls the actuator 221 based on the detection result of the position detection sensor 222 and the detection result of a shake detector such as a gyro sensor. The OIS IC 223 obtains the detection result of the shake detector from the lens controller 240. Further, the OIS IC 223 transmits a signal indicating the state of the optical image blur correction process to the lens controller 240.

  The diaphragm 260 is a member for adjusting the amount of light passing through the optical system. The diaphragm 260 includes, for example, a plurality of diaphragm blades, and the amount of light can be adjusted by opening and closing an opening formed by the blades. The diaphragm motor 261 is a driving unit for opening and closing the opening of the diaphragm 260.

  The focus lens 230 is a lens for changing the focus state of the subject image formed on the CCD image sensor 110 in the optical system. The focus lens 230 is composed of one or a plurality of lenses.

  The focus motor 233 drives the focus lens 230 to advance and retract along the optical axis of the optical system based on the control of the lens controller 240. Thereby, the focus state of the subject image formed on the CCD image sensor 110 by the optical system can be changed. As the focus motor 233, a stepping motor is used in the first embodiment. However, the present invention is not limited to this. For example, it can be realized by a servo motor, an ultrasonic motor, or the like.

  The lens controller 240 controls the entire interchangeable lens 200 such as the OIS IC 223 and the focus motor 233 based on the control signal from the camera controller 140. The lens controller 240 receives signals from the detector 212, the OIS IC 223, and the like and transmits them to the camera controller 140. In addition, the lens controller 240 transmits to the camera controller 140 information related to a mechanical end position described later, information related to an infinite end position, and information related to a close end position. The lens controller 240 performs the transmission / reception with the camera controller 140 via the lens mount 250 and the body mount 150.

  The lens controller 240 uses the SRAM 241 as a work memory at the time of control. The flash memory 242 stores a program and parameters used when the lens controller 240 is controlled.

  The flash memory 242 stores information on the mechanical end position, information on the infinite end position, and information on the close end position. Here, the mechanical end position and the infinite end position will be described with reference to FIG. The focus lens 230 can be driven along the optical axis in the interchangeable lens 200. Here, an end portion where the focus lens 230 can be physically driven is referred to as a mechanical end. That is, as shown in FIG. 2, the mechanical ends are present at both the end portions on the near end side and the end portion on the infinite end side. Here, the infinite end is a position closest to infinity among positions where the focus lens 230 determined by design can be focused. The closest end is a position closest to the focus position of the focus lens 230 determined by design. Here, the infinite margin is the distance between the infinite end and the mechanical end. On the other hand, the close margin is the distance between the close end and the mechanical end.

[1-2-3. Correspondence with the present invention)
The interchangeable lens 200 is an example of the interchangeable lens of the present invention. The camera body 100 is an example of the camera body of the present invention. The focus lens 230 is an example of the focus lens of the present invention. The focus motor 233 is an example of the driving means of the present invention. The lens controller 240 is an example of the autofocus control means of the present invention. The flash memory 242 is an example of a storage unit of the present invention. The body mount 150 is an example of an acquisition unit of the present invention. The camera controller 140 is an example of a generation unit of the present invention. The body mount 150 is an example of the notification means of the present invention.

  The CCD image sensor 110 is an example of an imaging unit of the present invention. The camera controller 140 is an example of the detection unit of the present invention. The camera controller 140 is an example of a second generation unit of the present invention. The body mount 150 is an example of the second notification means of the present invention.

[1-3. Operation)
[1-3-1. (Image preparation operation)
First, the operation of the camera system 1 for preparation for imaging will be described. FIG. 3 is a diagram illustrating signal transmission / reception for explaining the imaging preparation operation of the camera system 1.

  When the user turns on the power supply of the camera body 100 with the interchangeable lens 200 mounted on the camera body 100, the power supply 160 supplies power to the interchangeable lens 200 via the body mount 150 and the lens mount 250 ( S11). Next, the camera controller 140 requests authentication information of the interchangeable lens 200 from the lens controller 240 (S12). Here, the authentication information of the interchangeable lens 200 includes information regarding whether or not the interchangeable lens 200 is mounted and information regarding whether or not an accessory is mounted. The lens controller 240 responds to the lens authentication request from the camera controller 140 (S13).

  Next, the camera controller 140 requests the lens controller 240 to perform an initialization operation (S14). In response to this, the lens controller 240 performs initialization operations such as resetting the aperture and resetting the OIS lens 220. Then, the lens controller 240 returns to the camera controller 140 that the lens initialization operation has been completed (S15).

  Next, the camera controller 140 requests lens data from the lens controller 240 (S16). The lens data is stored in the flash memory 242. Therefore, the lens controller 240 reads the lens data from the flash memory 242 and sends it back to the camera controller 140 (S17). Here, the lens data is a characteristic value unique to the interchangeable lens 200 such as a lens name, an F number, a focal length, information on a mechanical end position, information on an infinite end position, information on a close end position, and the like.

  When the camera controller 140 grasps the lens data of the interchangeable lens 200 attached to the camera body 100, the camera controller 140 is ready for imaging. In this state, the camera controller 140 periodically requests lens state data indicating the state of the interchangeable lens 200 from the lens controller 240 (S18). The lens state data includes, for example, zoom magnification information by the zoom lens 210, position information of the focus lens 230, aperture value information, and the like. In response to this request, the lens controller 240 returns the requested lens state data to the camera controller 140 (S19).

  In this state, the camera system 1 can operate in a control mode in which an image indicated by the image data generated by the CCD image sensor 110 is displayed on the liquid crystal monitor 120 as a through image. This control mode is called live view mode. In the live view mode, the through image is displayed as a moving image on the liquid crystal monitor 120, so that the user can determine the composition for capturing a still image while viewing the liquid crystal monitor 120. The user can select whether to use the live view mode. In addition to the live view mode, control modes that can be selected by the user include a control mode in which an image generated based on image data generated by the CCD image sensor 110 is displayed on an electronic viewfinder (not shown). A contrast method is suitable as a method of autofocus operation in the live view mode. This is because in the live view mode, the image data is constantly generated by the CCD image sensor 110, so that it is easy to perform a contrast-type autofocus operation using the image data.

  When performing the contrast autofocus operation, the camera controller 140 requests contrast AF data from the lens controller 240 (S20). The contrast AF data is necessary for the contrast autofocus operation, and includes, for example, a focus drive speed, a focus shift amount, an image magnification, and contrast AF availability information.

[1-3-2. (Contrast AF operation)
The autofocus operation in the camera system 1 that has completed preparation for imaging will be described with reference to FIGS. 4 and 5. Here, a contrast type autofocus operation will be described. FIG. 4 is a flowchart for explaining the autofocus operation. FIG. 5 is a timing chart for the autofocus operation.

  Assume that the camera controller 140 is operating in the live view mode. In this state, the camera controller 140 periodically generates a vertical synchronization signal as shown in FIG. 5A. In parallel with this, the camera controller 140 generates an exposure synchronization signal as shown in FIG. 5C based on the vertical synchronization signal. This is because the camera controller 140 knows in advance the exposure start timing and the exposure end timing with reference to the vertical synchronization signal, so that the exposure synchronization signal can be generated. The camera controller 140 outputs a vertical synchronization signal to the timing generator 112 and outputs an exposure synchronization signal to the lens controller 240. The lens controller 240 acquires position information of the focus lens 230 in synchronization with the exposure synchronization signal. This point will be described later.

  The timing generator 112 periodically generates a readout signal of the CCD image sensor 110 and an electronic shutter drive signal as shown in FIG. 5B based on the vertical synchronization signal. The timing generator 112 drives the CCD image sensor 110 based on the readout signal and the electronic shutter drive signal.

  That is, the CCD image sensor 110 reads out pixel data generated by a large number of photoelectric conversion elements (not shown) in the CCD image sensor 110 to a vertical transfer unit (not shown) according to the read signal. In the first embodiment, the read signal and the vertical synchronization signal coincide with each other. However, this is not an essential matter for implementing the present invention. That is, the vertical synchronization signal and the readout signal may be shifted. In short, it is only necessary that the vertical synchronization signal and the readout signal are synchronized.

  Further, the CCD image sensor 110 performs an electronic shutter operation according to the electronic shutter drive signal. Thereby, the CCD image sensor 110 can sweep out unnecessary charges to the outside. The electronic shutter drive signal is composed of a group of a plurality of signals that are periodically transmitted within a short time. For example, 10 signals are transmitted as a group. The CCD image sensor 110 performs one electronic shutter operation on one signal while a group of electronic shutter drive signals are transmitted. If the number of signals included in the group of electronic shutter drive signals is increased, the charge accumulated in the CCD image sensor 110 can be surely swept out. However, the driving method of the CCD image sensor 110 becomes complicated.

  Therefore, the CCD image sensor 110 sweeps out the electric charge by the electronic shutter drive signal and reads out the pixel data to the vertical transfer unit (not shown) by the read signal, so that from the last signal of the group of electronic shutter drive signals to the vertical synchronization signal. During the period, the exposure operation is performed for the image data for the through image.

  In the above state, the camera controller 140 monitors whether or not the release button 130 is half-pressed (S101). In FIG. 5, it is assumed that the release button 130 is half-pressed at time t1. Then, as shown in FIG. 4D, the camera controller 140 transmits an AF start command to the lens controller 240. The AF start command is a command indicating that the contrast autofocus operation is started.

  When the AF start command is transmitted, the camera controller 140 transmits a hill-climbing start point movement command to the lens controller 240 at time t2. This command indicates to which position the focus lens 230 is moved when the contrast-type autofocus operation is started, and in which direction the focus lens 230 is moved during detection of the AF evaluation value. In response to this, the lens controller 240 controls the focus motor 233. The focus motor 233 moves the focus lens 230 to the position indicated by the hill-climbing start point movement command under the control of the lens controller 240 (S102).

  Next, the camera controller 140 transmits a hill climbing start command to the lens controller 240 at time t3 (S103). Here, the hill climbing start command is a command for instructing the driving direction of the focus lens 230, the driving speed of the focus lens 230, and the like. In response to an instruction from the camera controller 140, the lens controller 240 drives the focus lens motor 233 by control as shown in FIG. 4E. Specifically, the lens controller 240 controls the drive of the focus motor 233 so as to drive the focus lens 230 at the direction, speed, or the like designated by the hill climbing start command.

  Even after the hill-climbing start command is transmitted, the camera controller 140 continues to transmit the exposure synchronization signal to the lens controller 240 at a predetermined cycle as shown in FIG. 4C (S104).

  Further, the lens controller 240 sequentially stores in the DRAM 241 the number of pulses of the counter 243 when the exposure synchronization signal is switched from OFF to ON and the number of pulses of the counter 243 when the exposure synchronization signal is switched from ON to OFF. (S104).

  The CCD image sensor 110 transmits the image data that is exposed during the exposure period and generated to the camera controller 140 via the AD converter 111. Based on the received image data, the camera controller 140 calculates an evaluation value for autofocus operation (hereinafter referred to as an AF evaluation value for convenience) (S104). Specifically, a method for obtaining an AF evaluation value by obtaining a luminance signal from image data generated by the CCD image sensor 110 and integrating high-frequency components in the screen of the luminance signal is known. The calculated AF evaluation value is stored in the DRAM 141 in a state associated with the exposure synchronization signal.

  When the AF evaluation value and the exposure synchronization signal are stored in the DRAM 141 in association with each other, the camera controller 140 transmits a position information request command for requesting the lens position information stored in the DRAM 241 to the lens controller 240 (S105).

  When receiving the position information request command, the lens controller 240 transmits the position information of the focus lens 230 to the camera controller 140 (S106). In the present embodiment, every time the CCD image sensor 110 captures one frame, the camera controller 140 transmits a position information request command. Accordingly, the lens controller 240 transmits two pieces of lens position information stored in the DRAM 241 in response to acquiring the position information request command from the camera controller 140.

  When the position information of the focus lens 230 is acquired, the camera controller 140 associates the AF evaluation value stored in the DRAM 141 with the acquired position information (S107). The associated information is stored in the DRAM 141. The AF evaluation value and the position information of the focus lens are mutually associated with the exposure synchronization signal. Therefore, the camera controller 140 can store the AF evaluation value in association with the lens position information. For example, the AF evaluation value calculated using the image data exposed in the period a in FIG. 4C is stored in association with the average value of the position of the focus lens 230 at time t4 and the position of the focus lens 230 at time t5. Is done. As described above, the AF evaluation value calculated using the image data exposed in the period a in FIG. 4C is stored in the DRAM 141 at time t6.

  When the AF evaluation value is associated with the position information of the focus lens 230, the camera controller 140 determines whether or not the in-focus position of the focus lens has been extracted (S108). Specifically, the position of the focus lens 230 at which the AF evaluation value becomes the maximum value is extracted as the focus position.

  If the focus position of the focus lens can be extracted, the camera controller 140 transmits a focus position movement command to the lens controller 240 (time t7). The focus position movement command is a command indicating from which direction to which position the focus lens 230 is moved. The lens controller 240 drives the focus motor 233 according to the focus position movement command (S113). When the movement to the in-focus point is completed, the camera controller 140 transmits an AF completion command to the lens controller 240 (time t8). Thus, the autofocus operation is completed by the contrast method.

  If the focus position of the focus lens has not been extracted, the camera controller 140 determines whether or not the mounted interchangeable lens 200 has an infinite margin (S110).

  If it is determined that the lens has no infinite margin, the camera controller 140 determines whether or not the focus lens 230 has reached the mechanical end from the acquired lens position information (S111). If it is determined that the mechanical end has been reached, the camera controller 140 transmits a command for instructing the lens controller 240 to control the focus motor 233 to stop the focus lens 230 (S112).

  As described above, the camera system 1 according to the present embodiment detects the in-focus position even when the focus lens is driven to the mechanical end when the camera body 100 is equipped with an interchangeable lens having no infinite margin. When it is not possible, the focus lens is stopped at the mechanical end. That is, as shown in FIG. 6, when the peak of the AF evaluation value (contrast value) curve cannot be detected even if the focus lens is moved within the movable range, at the mechanical end where the AF evaluation value (contrast value) is the highest. The focus lens is stopped. This prevents the focus lens from being driven indefinitely even when an image is to be captured under conditions that prevent focusing. Even when an image is to be captured under conditions that prevent focusing, an image that is relatively in focus can be captured.

  On the other hand, when determining that the lens has an infinite margin, the camera controller 140 determines whether or not the current distance between the focus lens 230 and the mechanical end is equal to or less than a predetermined distance (S113). In the camera system 1 according to the present embodiment, the current distance between the focus lens 230 and the mechanical end is determined. However, such a configuration is not necessarily required. For example, it may be determined whether the distance between the current position of the focus lens 230 and the infinite end is a predetermined distance or less.

  If it is determined that the current distance between the focus lens 230 and the mechanical end is equal to or less than the predetermined distance, the camera controller 140 determines whether or not the infinite margin of the interchangeable lens 200 is shorter than the predetermined distance (S114). If it is determined that the infinite margin is shorter than the predetermined distance, the camera controller 140 notifies the lens controller 240 of a command for changing the drive speed of the focus lens 230 to a low speed (S115).

  That is, when the infinite margin is longer than the predetermined distance, the focus lens 230 is always driven at a high speed regardless of the position of the focus lens 230 as shown in FIG. When the infinite margin is long, even if there is a peak of the AF evaluation value (contrast value) near the infinite end, the camera controller 140 can sufficiently perform the AF evaluation value (contrast even at a location beyond the peak of the mountain. This is because (value) can be detected. On the other hand, when the infinite margin is shorter than the predetermined distance, as shown in FIG. 7B, when the distance between the position of the focus lens 230 and the mechanical end becomes a predetermined length or less, the drive speed of the focus lens 230 is reduced. Change to low speed. This is because if the peak of the AF evaluation value (contrast value) is near the infinite end when the infinite margin is short, the camera controller 140 can sufficiently detect the AF evaluation value (contrast at a location beyond the peak of the mountain. This is because the (value) may not be detected. For example, as shown in FIG. 8, when the infinite margin is short and the focus lens 230 is driven at a high speed, the AF evaluation value (contrast value) is not detected at the infinite margin position, and the peak of the AF evaluation value (contrast value) is detected. In some cases, it is impossible to find the peak.

  Therefore, in the camera system 1 according to the present embodiment, the infinite margin of the interchangeable lens 200 mounted is shorter than a predetermined distance, and the distance between the position of the focus lens 230 and the mechanical end is smaller than the predetermined distance. If it is too short, the driving speed of the focus lens 230 is reduced. As a result, even when an interchangeable lens with a short infinite margin is attached, the peak of the AF evaluation value (contrast value) can be detected without any omission, and the auto focus of the relatively high-speed contrast method can be detected. Can be realized.

[1-3-3. Summary of the present embodiment]
The camera system 1 according to the present embodiment is a camera system 1 including an interchangeable lens 200 and a camera body 100. The interchangeable lens 200 includes a focus lens 230, a focus motor 233 that drives the focus lens 230, and a focus. The distance between the lens controller 240 that performs autofocus by controlling the motor 233, the end of the movable range of the focus lens 230, and the end on the infinite side where the lens controller 240 can detect the in-focus position. A flash memory 242 that stores specific information that can specify a certain infinite margin, and the camera body 100 specifies the body mount 150 that acquires specific information from the interchangeable lens 200 and the specific information acquired by the body mount 150. According to possible infinite margin Includes a camera controller 140 that generates a control signal for driving the focus lens 230 to the focus motor 233 at any speed, the body mount 150 to notify the control signal generated by the camera controller 140 to the interchangeable lens 200, a. As a result, even when an interchangeable lens with a short infinite margin is attached, the peak of the AF evaluation value (contrast value) can be detected without any omission, and the auto focus of the relatively high-speed contrast method can be detected. Can be realized.
[2. Other Embodiments]
As described above, the first embodiment has been described as the embodiment of the present invention. However, the present invention is not limited to these. Therefore, other embodiments of the present invention will be described collectively in this section.

  In the first embodiment, the driving speed of the focus lens 230 is changed according to the presence or absence of the infinite margin, which is the distance between the infinite end of the interchangeable lens 200 and the mechanical end on the infinite end, and the magnitude of the infinite margin. It was. However, it is not necessarily limited to such a configuration. For example, the driving speed of the focus lens 230 may be changed in accordance with the presence or absence of the closeness margin, which is the distance between the close end of the interchangeable lens 200 and the mechanical end on the close end side, and the closeness margin. In this example, when there is no close margin, if the focus lens 230 reaches the mechanical end and is not in focus, the drive of the focus lens 230 is stopped. Further, when the closeness margin is large, the speed is not particularly reduced even if the distance between the focus lens 230 and the mechanical end becomes a predetermined amount or less. On the other hand, when the closeness margin is small, when the distance between the focus lens 230 and the mechanical end becomes a predetermined amount or less, the drive speed of the focus lens 230 is reduced. As a result, even when an interchangeable lens with a short margin is attached, the peak of the peak of the AF evaluation value (contrast value) can be detected without any omission, and a relatively high-speed contrast autofocus can be performed. Can be realized.

  In Embodiment 1 of the present invention, a camera body that does not include a movable mirror is illustrated, but the present invention is not limited to this. For example, a movable mirror may be provided in the camera body, or a prism for separating the subject image may be provided. Moreover, the structure provided with a movable mirror not in a camera body but in an adapter may be sufficient.

  In the first embodiment of the present invention, the CCD image sensor 110 is exemplified as the imaging device, but the present invention is not limited to this. For example, it may be composed of a CMOS image sensor or an NMOS image sensor.

  The present invention can be applied to an imaging apparatus such as a digital still camera or a digital video camera.

Block diagram of camera system 1 Schematic diagram for explaining the movable range of the focus lens 230 Flow chart for explaining pre-imaging operation Flow chart for explaining contrast AF operation Timing chart for explaining the contrast AF operation Schematic diagram for explaining Hayama Schematic diagram for explaining a change in the driving speed of the focus lens 230 Schematic diagram for explaining the problems of AF operation at high speed

Explanation of symbols

100 Camera Body 110 CCD Image Sensor 111 AD Converter 112 Timing Generator 120 LCD Monitor 130 Release Button 140 Camera Controller 141 DRAM
142 Flash Memory 150 Body Mount 160 Power Supply 170 Card Slot 171 Memory Card 200 Interchangeable Lens 210 Zoom Lens 211 Drive Mechanism 212 Detector 220 OIS Lens 221 Actuator 222 Position Detection Sensor 223 OIS IC
230 Focus lens 233 Focus motor 240 Lens controller 241 SRAM
242 Flash memory 243 Counter 250 Lens mount 260 Aperture 261 Aperture motor

Claims (8)

A camera system comprising an interchangeable lens and a camera body,
The interchangeable lens is
A focus lens,
Driving means for driving the focus lens;
Autofocus control means for performing autofocus by controlling the drive means;
Storage means for storing specific information capable of specifying an infinite margin, which is a distance between an end of the movable range of the focus lens and an end on the infinite side where the autofocus control means can detect a focus position; With
The camera body is
Obtaining means for obtaining the specific information from the interchangeable lens;
Generating means for generating a control signal for driving the focus lens at an arbitrary speed in accordance with an infinite margin that can be specified from the specific information acquired by the acquiring means;
Notifying means for notifying the interchangeable lens of the control signal generated by the generating means,
Camera system. A camera system comprising an interchangeable lens and a camera body,
The interchangeable lens is
A focus lens,
Driving means for driving the focus lens;
Storage means for storing specific information capable of specifying an infinite margin that is a distance between the end of the movable range of the focus lens and the infinite end;
The camera body is
Obtaining means for obtaining the specific information from the interchangeable lens;
Generating means for generating a control signal for driving the focus lens at an arbitrary speed in accordance with an infinite margin that can be specified from the specific information acquired by the acquiring means;
Notifying means for notifying the interchangeable lens of the control signal generated by the generating means,
Camera system. The generating means includes
In the case where the infinite margin that can be specified from the specific information acquired by the acquisition means is a first value, the infinite margin is faster than the case where the infinite margin is a second value that is smaller than the first value. Generating a control signal for controlling the driving means to drive the focus lens;
The camera system according to claim 2. The generating means includes
When the distance between the current position of the focus lens and the end of the movable range of the focus lens or the infinite end is shorter than a predetermined value, an infinite margin that can be specified from the specific information acquired by the acquisition unit And generating a control signal for causing the driving means to drive the focus lens at an arbitrary speed.
The camera system according to claim 2. The generating means includes
When the distance between the current position of the focus lens and the end of the movable range of the focus lens or the infinite end is shorter than a predetermined value, the infinite can be specified from the specific information acquired by the acquisition unit A control signal for controlling the drive means to drive the focus lens at a higher speed than when the infinite margin is a second value smaller than the first value when the margin is a first value; Generate,
The camera system according to claim 3. The camera body is
Imaging means for capturing a subject image and generating image data;
Detecting means for detecting a contrast value of an image indicated by the image data generated by the imaging means;
A second generation means for generating a control signal for controlling the drive means to drive the focus lens in accordance with a detection result by the detection means;
A second notification means for notifying the interchangeable lens of the control signal generated by the second generation means,
The camera system according to claim 2. A camera system comprising an interchangeable lens and a camera body,
The interchangeable lens is
A focus lens,
Driving means for driving the focus lens;
Storage means for storing specific information capable of specifying a close margin that is a distance between an end of the movable range of the focus lens and a close end;
The camera body is
Obtaining means for obtaining the specific information from the interchangeable lens;
Generating means for generating a control signal for causing the driving means to drive the focus lens at an arbitrary speed according to the closest margin that can be specified from the specific information acquired by the acquiring means;
Notifying means for notifying the interchangeable lens of the control signal generated by the generating means,
Camera system. A camera system comprising an interchangeable lens and a camera body,
The interchangeable lens is
A focus lens,
Driving means for driving the focus lens;
Autofocus control means for performing autofocus by controlling the drive means;
Storage means for storing specific information capable of specifying a closeness margin that is a distance between an end of a movable range of the focus lens and a close end on which the autofocus control means can detect a focus position; With
The camera body is
Obtaining means for obtaining the specific information from the interchangeable lens;
Generating means for generating a control signal for driving the focus lens at an arbitrary speed in accordance with an infinite margin that can be specified from the specific information acquired by the acquiring means;
Notifying means for notifying the interchangeable lens of the control signal generated by the generating means,
Camera system.

Images