JP2008233668A - Autofocus system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an autofocus system capable of easily adjusting an AF speed (focus movement speed) so that a focusing state is obtained at a timing intended by a photographer by changing the AF speed so as to obtain the timing becoming the focusing state when a camera is stopped even in the case that the camera is moved toward or away from a subject in order to automatically move the focus from a defocusing state to the focusing state. <P>SOLUTION: During autofocus control, a CPU 10 of a lens device detects the movement of a camera by a position sensor 40, and also detects a focusing state. If the amount of movement of the focus, required to bring to focus, is increased, the focus is moved at a speed higher a focus moving speed assigned when the camera is stopped. If the amount of movement of the focus is decreased, the focus is moved at a speed lower than the focus moving speed assigned when the camera is stopped. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an autofocus system, and more particularly to an autofocus system that changes a focus moving speed (AF speed) during autofocus (AF) control.

  2. Description of the Related Art Broadcast or commercial television cameras equipped with an autofocus (AF) function that automatically controls the focus of a photographic optical system so that the photographic optical system is focused on a predetermined subject are known. ing. In addition, a TV camera equipped with such an AF function can be adjusted from the controller, PC, etc. with the focus moving speed (AF speed) when the focus moves to the in-focus position. It is known (see, for example, Patent Document 1).

Conventionally, there is a case where a scene where the focus is gradually moved from an out-of-focus state (unfocused state) to an in-focus state (in-focus state) in a song program or the like is shot using AF. At this time, the AF speed is adjusted so that the in-focus state is achieved at a timing intended by the photographer.
JP 2004-85673 A

  When the focus is gradually shifted from the out-of-focus state to the in-focus state by AF as described above, if there is no change in the distance between the TV camera and the subject, the AF speed is adjusted to adjust the AF speed at the timing the cameraman intended. It can be in a focused state. However, when moving the focus to the focused state by AF while moving the camera close to or away from the subject with a tripod, pedestal, etc., adjust the focus to the focused state at the intended timing. There was a problem that was difficult.

  The present invention has been made in view of such circumstances, and even when the camera is moved in the perspective direction with respect to the subject when the focus is shifted from the out-of-focus state to the in-focus state by AF. An object of the present invention is to provide an autofocus system capable of easily adjusting an AF speed (focus movement speed) so that a focused state is achieved at a timing intended by a cameraman.

  In order to achieve the object, the autofocus system according to claim 1 is an autofocus system that performs autofocus control for controlling the focus of the photographing optical system so that the photographing optical system of the camera is in focus. A focus movement amount information acquisition unit that acquires information about a movement amount of a focus until the photographing optical system changes from a current focus state to a focus state; and a subject that the camera focuses with the autofocus unit Based on the information acquired by the focus movement amount information acquisition means, using the focus movement speed when stopped in the perspective direction as a reference speed, the imaging optical system is changed from the current focus state to the in-focus state. Focus moving speed changing means for changing the moving speed of the focus with respect to the reference speed, When the amount of movement of the focus until focusing is increased by moving the camera in the perspective direction, the movement speed of the focus is made faster than the reference speed, and the amount of movement of the focus is decreased. In this case, a focus moving speed changing means for making the moving speed of the focus slower than the reference speed is provided.

  According to the present invention, even when the camera is moved in the perspective direction with respect to a subject to be focused by autofocus (AF) control, the focused state is achieved at the same timing as when the camera is stopped. Thus, the focus moving speed (AF speed) is automatically changed. Therefore, if the AF speed is adjusted assuming that the camera is stopped, even if the focus is shifted to the in-focus state while moving the camera, the in-focus state is reached at the timing that the cameraman intended. The AF speed can be adjusted so that

  According to a second aspect of the present invention, in the first aspect of the invention, the focus movement amount information acquisition unit includes a camera movement state detection unit that detects a movement state of the camera in the perspective direction, and the photographing. A focus state detection unit that detects a focus state of whether the optical system is a front pin or a rear pin, and the focus movement speed changing unit includes the camera movement state detected by the camera movement state detection unit, and the focus state. Based on the focus state detected by the state detection means, it is characterized in determining whether the amount of movement of the focus until the in-focus state is increased or decreased.

  The present invention is a configuration for determining whether or not the amount of movement of the focus until the in-focus state is increased or decreased when the camera is moving in a perspective direction with respect to a subject to be focused by AF control. The one aspect | mode is shown.

  According to the autofocus system of the present invention, when the focus is shifted from the out-of-focus state to the in-focus state by the AF, the AF is focused even when the camera is moved in the perspective direction with respect to the subject. When moving the camera from the out-of-focus state to the in-focus state, even if the camera is moved in the perspective direction with respect to the subject, the AF speed (focus) (Moving speed) can be easily adjusted.

  Hereinafter, the best mode for carrying out an autofocus system according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram showing the configuration of a lens system to which the present invention is applied. The lens system shown in the figure is composed of, for example, a photographing lens (photographing optical system) mounted by mounting on a camera body (not shown) of a television camera for broadcasting or business use, and a control system for controlling the photographing lens. ing. Further, the lens system shown in FIG. 1 is configured as a lens device in which a photographing lens and many components of a photographing lens control system are integrated. However, any device may be used for the lens system.

  The photographic lens is a component related to a photographic optical system that forms a subject image on an imaging surface of an imaging element (CCD or the like) of the camera body, and is configured by various optical components supported in a lens barrel. In the lens barrel, in addition to various fixed lens groups, a focus lens (group) FL and a zoom lens (group) ZL shown in the figure are arranged as a lens group movable in the optical axis direction. . When the focus lens FL moves, the focus position (subject distance) changes, and when the zoom lens ZL moves, the image magnification (focal distance) changes. In addition, the photographing lens is provided with an aperture I shown in the figure which is driven to open and close to change the brightness of the image.

  The control system for controlling the taking lens is composed of a CPU 10, amplifiers FA, ZA, IA, motors FM, ZM, IM, potentiometers FP, ZP, IP, focus demand 18, zoom demand 20, AF processing unit 30, and the like. .

  The CPU 10 performs overall control of the entire system. When drive signals are output from the CPU 10 to the amplifiers FA, ZA, and IA via the D / A converter 12, the motors FM, ZM, and IM receive the drive signals. It is driven at a rotation speed corresponding to the value (voltage). The motors FM, ZM, and IM are connected to the focus lens FL, the zoom lens ZL, and the diaphragm I of the photographing lens. When the motors FM, ZM, and IM are driven, the motors FM, ZM, and IM are driven at a speed according to their rotational speed. The focus lens FL, zoom lens ZL, and aperture I are driven.

  Potentiometers FP, ZP, and IP that output voltage signals corresponding to their rotational positions are connected to the output shafts of the motors FM, ZM, and IM. The voltage signals from the potentiometers FP, ZP, and IP are A signal indicating the position of the lens FL, the position of the zoom lens ZL, and the position (aperture amount) of the diaphragm I is given to the CPU 10 via the A / D converter 14.

  Therefore, the CPU 10 can control the positions or operating speeds of the focus lens FL, the zoom lens ZL, and the diaphragm I to a desired state by drive signals given to the amplifiers FA, ZA, and IA.

  In this specification, the control for the focus position (subject distance) of the photographing lens by controlling the position or operation speed of the focus lens FL is called focus control (or focus control), and the zoom lens ZL Control that targets the photographing magnification (focal length) of the photographing lens by controlling the position or operation speed is called zoom control (zoom control).

  In the figure, a focus demand 18 and a zoom demand 20 are controllers provided with a manual operation member for manually specifying a target position and moving speed of the focus (focus lens FL) and zoom (zoom lens ZL) of the photographing lens. It is. These focus demand 18 and zoom demand 20 are, for example, for a lens apparatus in which a photographing lens and the CPU 10, amplifier FA, ZA, IA, motor FM, ZM, IM, potentiometer FP, ZP, IP, and the like are integrated. An analog signal connected by a cable or the like and sent from the focus demand 18 or the zoom demand 20 is converted into a digital signal by the A / D converter 14 and read into the CPU 10.

  In the lens system according to the present embodiment, manual focus (MF) and auto focus (AF) controls are switched as focus control by an AF switch SW1 operated by an operator.

  During MF control, focus control is performed in accordance with a focus command signal from the focus demand 18. When the manual operation member of the focus demand 18 is operated during the MF control, for example, a focus command signal for designating a focus target position corresponding to the position of the operation member is given to the CPU 10. The CPU 10 controls the position of the focus lens FL by controlling the motor FM with a drive signal output to the amplifier FA so that the focus position becomes the target position specified by the focus command signal. The AF control will be described later.

  The zoom control is performed according to a zoom command signal given from the zoom demand 20. When a manual operation member of the zoom demand 20 is operated, for example, a zoom command signal for designating a moving speed of a zoom target corresponding to the position of the operation member is given to the CPU 10. The CPU 10 controls the moving speed of the zoom lens ZL by controlling the motor ZM with a drive signal output to the amplifier ZA so that the moving speed of the zoom becomes the target moving speed specified by the zoom command signal.

  The control of the aperture I (aperture control) is performed according to an aperture command signal given to the CPU 10 from a camera body (not shown).

  The AF processing unit 30 is a processing unit for detecting the contrast of a video (image) photographed by the image sensor of the camera body, and includes various circuits that omit details. The AF processing unit 30 receives a video signal of a real-time video imaged by an image sensor of the camera body, and controls the image (subject image) for each frame image of the video signal. The AF evaluation value shown is detected by the AF processing unit 10. The focus evaluation value detected by the AF processing unit 30 is read by the CPU 10.

  When the AF switch SW1 is turned on during MF control, the CPU 10 switches focus control to AF control, and performs focus control so that the photographic lens is in focus based on the focus evaluation value obtained from the AF processing unit 30. . Here, in the present embodiment, so-called one-shot AF is employed, and when the AF switch SW1, which is an automatic return type switch, is turned on once during MF control, the AF control is switched to and shooting is performed by AF control. When the lens is in focus, it automatically returns to MF control. Note that switching between MF control and AF control is not limited to the one-shot AF mode. For example, once switched to AF control, the AF control may be continuously executed until switching to MF control is instructed, or another mode may be used.

  During the AF control, the CPU 10 reads the focus evaluation value from the AF processing unit 30 and moves the focus (focus lens FL) so that the focus evaluation value becomes maximum (maximum). Focus control for maximizing the focus evaluation value is performed, for example, by a hill climbing method. That is, wobbling is performed as appropriate to displace the focus lens FL by a minute amount toward the close side and the infinity side, and the focus evaluation values at the respective displacement points at the time of wobbling are compared. Accordingly, when the direction in which the focus evaluation value increases is detected, the focus lens FL is moved in that direction. When the direction in which the focus evaluation value increases is not detected, the focus evaluation value is determined to be in focus. The lens FL is stopped. As a result, the focus is set at a position where the photographing lens is brought into focus. Note that the configuration and processing for performing AF control are not limited to those shown in this embodiment.

  Next, processing related to the focus movement speed (AF speed) during the AF control will be described.

  The focus movement speed (AF speed) when the focus (focus lens FL) is shifted from the out-of-focus state (the out-of-focus position) to the in-focus state (the in-focus position) by AF control is a lens device, that is, a television camera. It can be divided into a speed when the camera is stopped and a speed when the television camera is moving.

  The AF speed when the TV camera is stopped refers to the focus moving speed when the TV camera is stopped in the perspective direction (front-rear direction) with respect to the subject to be focused, and the AF speed at this time Is set in the same manner as any conventional method. For example, the AF speed is set in consideration of the amount of change in the focus evaluation value during wobbling, the aperture value, and the like. It is also known that a speed adjustment knob (speed VR) is provided on the focus demand 18 or the like so that the photographer can set a desired AF speed, and the AF speed is set based on the set value of the speed VR. Yes.

  Note that the AF speed when the TV camera is stopped is particularly referred to as a stop-time AF speed.

  On the other hand, the AF speed when the TV camera is moving indicates the focus movement speed when the TV camera is moving in the perspective direction with respect to the subject to be focused. It is set by changing (adjusting) the stop-time AF speed based on the stop-time AF speed. Although details will be described later, when the focus is shifted from the out-of-focus state to the in-focus state by AF control, the timing at which the television camera is stopped and in the moving state are different. Therefore, even when the TV camera is moving, the AF speed is automatically set with respect to the stop AF speed so that the in-focus state is achieved at the same timing as when the TV camera is stopped. It has been changed.

  Here, as shown in FIG. 1, the lens device is provided with a posture sensor 40 (for example, an acceleration sensor) for detecting the moving state of the television camera in the perspective direction with respect to the subject to be focused. Then, the detection signal of the attitude sensor 40 is read into the CPU 10, and the movement state (movement speed and movement amount) of the television camera is detected based on the detection signal. The CPU 10 acquires information on the amount of movement of the focus until the photographic lens is brought into focus, based on the moving state of the TV camera and the current focus state (whether it is the front pin or the rear pin). The amount of change in the AF speed is obtained using data stored in advance or using a predetermined calculation formula. Note that the current focus state is determined by, for example, a focusing direction in which the focus is moved as a direction in which the focus evaluation value increases.

  The lens device is provided with a posture sensor sensitivity changing unit 42 that changes the sensitivity of the posture sensor 40. The posture sensor sensitivity changing unit 42 changes the sensitivity of the CPU 10 to read the detection signal of the posture sensor 40. For example, when the position of the operation knob of the posture sensor sensitivity changing unit 42 is operated, the operation position of the operation knob is changed. Is read by the CPU 10, and the sensitivity of reading with respect to the detection signal of the attitude sensor 40 is changed according to the operation position. Thus, the cameraman can intentionally change the movement state of the television camera recognized by the CPU 10, and as a result, the AF speed automatically set when the television camera is indirectly moving is set to the cameraman. Can be changed intentionally.

  The AF speed is changed by changing the value of the AF gain when the CPU 10 controls the focus, for example. That is, the value of the drive signal output from the CPU 10 to the amplifier FA (see FIG. 1) of the motor FM that drives the focus lens FL indicates the rotational speed of the motor FM, and the calculation formula for obtaining the value of the drive signal is a predetermined formula. By including the gain (AF gain) and changing the value of the AF gain, the moving speed of the focus is changed. In this embodiment, the focus gain speed when the TV lens is moving is changed by setting the AF gain when moving the focus at the stop AF speed to 1, and changing the AF gain to 1. Shall be. When control is performed such that the movement position (target position) of the focus lens FL is determined every predetermined time and the focus lens FL is moved, the movement distance to the target position is multiplied by a predetermined amount and the magnification is It is also possible to change the AF speed by changing.

  Note that the posture sensor 40 and the posture sensor sensitivity changing unit 42 may be installed in a portion other than the lens device, for example, a controller such as the focus demand 18 or a tripod or pedestal that supports the television camera. Furthermore, information equivalent to the posture sensor 40 may be obtained from tripod control information. Furthermore, when the attitude sensor is installed at a plurality of locations, for example, when it is provided in a controller such as the lens device and the focus demand 18, a selection switch for selecting which sensor output is to be enabled is provided for selection. Alternatively, the determination may be made using an interface signal between the controller and the lens. Further, the determination may be made by communication.

  Hereinafter, a processing procedure in the CPU 10 regarding the change of the AF speed will be described. FIG. 2 is a flowchart showing a schematic processing procedure of the CPU 10 in changing the AF speed. When the AF switch SW1 is turned on and an instruction to switch from the MF control to the AF control is given, the CPU 10 firstly needs information for determining the stop-time AF speed such as the speed VR provided in the focus demand 18 or the like. Is read (step S10). Thereby, the AF speed at the time of stopping in a state where the television camera is stopped is determined.

  Next, the output of the attitude sensor 40 is read (step S12), and the moving distance of the television camera in the perspective direction with respect to the subject is calculated (step S14). Subsequently, the output of the attitude sensor sensitivity changing unit 42 is read (step S16), and the movement distance when the output of the attitude sensor 40 is read with the sensitivity corresponding to the output value is recalculated.

  Next, the current focus state of the taking lens is determined (step S18). That is, with the start of AF control, the focus movement direction (focusing direction) in which the focus evaluation value increases is detected, and it is determined from the direction whether the current focus state is the front focus or the rear focus. Subsequently, the AF speed at stop is changed based on the focus state and the movement distance obtained in step S14, and the focus movement speed when the television camera is moving is calculated. Then, an AF gain value for driving the focus (focus lens FL) at the calculated focus movement speed is calculated (step S20).

  FIG. 3 is a flowchart showing a procedure for determining how to change the AF speed. First, it is determined whether or not there is no focus movement, that is, whether or not it is in focus (step S30). If YES is determined, the AF speed, that is, the focus movement speed is not changed (step S32). If NO is determined in step S30, that is, if the in-focus state is present, it is subsequently determined whether or not the current focus state is the front pin (step S34).

  Here, FIG. 4 shows the relationship between the position of the TV camera 60, the position of the subject (person) 62 to be focused, and the position of the subject currently focused on the TV camera 60 (focus position). In FIG. 9A, when the in-focus direction is the infinity direction as in the case where the focus position is set at the point B, it is determined as the front pin, and the focus position is set at the point A. In the case where the in-focus direction is the closest direction as in the case, the rear pin is determined.

  In the case where the focus position is set to point B in FIG. 4A, if it is determined as YES in step S34, it is subsequently determined whether or not the TV camera has approached the subject (step S36). When the television camera 60 approaches the subject 62 with respect to the state of FIG. 4A, the state changes to the state as shown in FIG. In this case, YES is determined in step S36. At this time, the focus position set at point B in FIG. 4A approaches the subject 62 as the television camera 60 moves, so the focus movement speed is slowed down (step S38). In other words, the amount of movement of the focus until the in-focus state is reduced due to the movement of the TV camera. Reduce.

  When NO is determined in step S36, that is, when the state shown in FIG. 4A is changed to the state shown in FIG. 4C, the point B is set in FIG. 4A. Since the focus position moves away from the subject 62 with the movement of the television camera 60, the focus movement speed is increased (step S40). In other words, the movement of the TV camera increases the amount of movement of the focus until the in-focus state is reached. Reduce.

  If NO is determined in step S34, that is, if the focus position is set to point A in the state of FIG. 4A, it is subsequently determined whether or not the TV camera has approached the subject. (Step S42). If the state shown in FIG. 4A changes to the state shown in FIG. 4B, YES is determined in step S42. At this time, since the focus position set at the point A in FIG. 4A moves away from the subject 62 with the movement of the television camera 60, the focus movement speed is increased (step S44). In other words, the movement of the TV camera increases the amount of movement of the focus until the in-focus state is reached. Reduce.

  When NO is determined in step S42, that is, when the state shown in FIG. 4A is changed to the state shown in FIG. 4C, the point A is set in FIG. 4A. Since the focused position approaches the subject 62 as the television camera 60 moves, the focus moving speed is decreased (step S46). In other words, the amount of movement of the focus until the in-focus state is reduced due to the movement of the TV camera. Reduce.

  By changing the focus movement speed (AF speed) as described above, even when the TV camera is moving, the focus is set to the in-focus state at the same timing as when the TV camera is stopped. can do.

  Note that as to how much the focus moving speed is changed, for example, the focus moving speed may be changed by a speed corresponding to a change in the focus moving amount changed by the movement of the television camera. That is, with respect to the focus movement amount X0 when the focus is moved for a certain time T at the stop AF speed, the movement amount of the focus to the in-focus state changed by the movement of the TV camera at the certain time T. The amount of change (change amount DX) is added or subtracted (when the movement amount increases, a positive value change DX, and when the movement amount decreases, a negative value change DX) Both are added), and the movement amount (X0 + DX) of the focus obtained thereby becomes a movement amount during a fixed time T at the changed focus movement speed. If the focus moving speed is repeatedly changed every predetermined time until the in-focus state is reached, the TV camera stops the timing when the in-focus state is reached while the TV camera is moving. It is possible to substantially match the timing when the in-focus state is reached.

  Also, it is not necessary to change the AF speed so that the timing when the TV camera is in focus and the timing when the TV camera is stopped and the timing when the TV camera is stopped completely match. If the amount of focus movement until the in-focus state is increased by the movement of the TV camera as described above, the AF speed is increased, and the amount of focus movement until the in-focus state is reached by the movement of the TV camera is If it decreases, the AF speed may be slowed to reduce the significant change in the in-focus timing when the TV camera is moving.

  As described above, in the above-described embodiment, the case where the in-focus position cannot be grasped in the out-of-focus state has been described as the AF control. However, the distance to the subject is measured by a predetermined distance measuring unit, and the position corresponding to the subject distance In the case of adopting a distance measuring AF control for focusing by moving the focus, it is not necessary to detect the moving state of the television camera using a sensor such as the attitude sensor 40.

  For example, a phase difference method is well known as a distance measurement method, and a process related to changing the AF speed when the AF control of the distance measurement method such as the phase difference method is employed will be described with reference to the flowchart of FIG.

  First, the distance to the subject (subject distance) is calculated using the distance measuring means (step S60). Subsequently, the current focus position is read (step S62). As a result, information regarding the amount of movement of the focus from the current focus state to the in-focus state is acquired. Next, the focus movement target time is read (step S64). Here, the focus movement target time indicates the time from when the focus is in the in-focus state to the in-focus state. For example, the initial value (after the AF control is started (the AF switch SW1 is turned on) is in the in-focus state. The time until the camera is set by a predetermined operation input means, and a value may be set sensuously by an operation input means such as a volume, or a numerical value may be input. .

  Next, the focus movement speed is calculated (step S66). Here, the focus movement speed is set to a speed at which the time until the focus reaches the focus position (focus position) corresponding to the subject distance with respect to the current focus position becomes the focus movement target time.

  Then, the focus is driven at the focus movement speed calculated in step S66 (step S68). While repeating the above process, the focus movement target time is set to a value obtained by subtracting the elapsed time from the time when this process was started (the time when the initial value was set as the focus movement target time) from the initial value. Thereby, even when the television camera is moving, the focus is set to the in-focus state at the same timing as when the television camera is stopped. In this embodiment, the focus movement target time is set, but when the TV lens is moving by setting the AF speed at the stop when the TV camera is stopped as in the above embodiment. Even so, the focus can be brought into focus at the same timing as when the television camera is stopped. In other words, the time required to move the focus to the in-focus position at the AF speed at the time of stop may be set as the focus movement target time.

  Further, when the subject distance is detected using the distance measuring means, the subject distance is not limited to change due to the movement of the television camera, but may be a case where the subject distance changes due to the subject movement. The AF speed can be appropriately changed by the processing of the flowchart of FIG. That is, in the AF control using the distance measuring means, the change of the AF speed assuming that the television camera moves in the perspective direction with respect to the subject moves the subject not only when the television camera actually moves. Thus, the processing is effective even when the television camera moves in the perspective direction relative to the subject, and the present invention is not limited to use when the television camera is actually moved.

FIG. 1 is a block diagram showing the configuration of a lens system to which the present invention is applied. FIG. 2 is a flowchart showing a schematic processing procedure in the CPU regarding the change of the AF speed. FIG. 3 is a flowchart showing a specific determination procedure regarding the AF speed change. FIG. 4 is an explanatory diagram used for explaining the change of the AF speed. FIG. 5 is a flowchart showing a processing procedure related to an AF speed change in a system that performs AF control of a distance measurement method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... CPU, 18 ... Focus demand, 20 ... Zoom demand, 30 ... AF processing part, 40 ... Attitude sensor, 60 ... TV camera, 62 ... Subject, FL ... Focus lens (group), ZL ... Zoom lens (group), I: Aperture, FM, ZM, IM ... Motor, FP, ZP, IP ... Potentiometer, SW1 ... AF switch

Claims (2)

In an autofocus system that performs autofocus control for controlling the focus of the photographing optical system so that the photographing optical system of the camera is in focus,
Focus movement amount information acquisition means for acquiring information on the movement amount of the focus until the photographing optical system changes from the current focus state to the in-focus state;
Based on the information acquired by the focus movement amount information acquisition unit, the focus movement speed when the camera is stopped in the perspective direction with respect to the subject to be focused by the autofocus unit is used as the reference speed. Focus moving speed changing means for changing the moving speed of the focus from the current focus state to the in-focus state with respect to the reference speed, the camera moving in the perspective direction, When the amount of movement of the focus until it reaches the focus state increases, the movement speed of the focus is made faster than the reference speed, and when the amount of movement of the focus decreases, the movement speed of the focus is made higher than the reference speed. A focus movement speed changing means that also slows down,
An autofocus system characterized by comprising The focus movement amount information acquisition unit includes a camera movement state detection unit that detects a movement state of the camera in the perspective direction, and a focus state detection unit that detects a focus state of whether the photographing optical system is a front pin or a rear pin. With
The focus movement speed changing unit is configured to move the focus until the in-focus state is reached based on the movement state of the camera detected by the camera movement state detection unit and the focus state detected by the focus state detection unit. 2. The autofocus system according to claim 1, wherein it is determined whether the amount increases or decreases.

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