JP4855702B2 - Auto focus system - Google Patents

Description

  The present invention relates to an autofocus system, and more particularly to an autofocus system that can be used in combination with manual focus (MF) and autofocus (AF).

  Autofocus (AF), which is used in TV cameras and video cameras, detects the contrast of a subject image shot based on the video signal obtained by the image sensor, and controls the focus so that the contrast becomes maximum (maximum). A contrast method is generally used. The contrast of the subject image is quantitatively detected by, for example, an integrated value obtained by extracting a high frequency component from a video signal obtained by an image sensor and integrating the high frequency component signal for each field. Note that the integrated value is a value indicating the degree of focusing and the high contrast of the subject image, and is referred to as a focus evaluation value in this specification.

Conventionally, even in the AF mode in which such AF control is performed, if an MF operation (manual operation member operation) is performed, the MF operation is prioritized over the AF, and focus control is performed according to the MF operation. MF priority AF mode is known (see, for example, Patent Documents 1 and 2). Further, when an MF operation is performed in such an MF-priority AF mode and then the MF operation is stopped, AF control is automatically resumed in Patent Document 1, and an AF start switch is turned on in Patent Document 2. The AF control is not resumed until it is performed.
JP-A-8-29665 Japanese Patent Laid-Open No. 2003-337278

  By the way, when priority is given to the MF operation in the AF mode, if AF is to be used for final focus adjustment after the MF operation, the AF is automatically restarted after the MF operation as in Patent Document 1. Is desirable. On the other hand, when it is desired to perform final focus adjustment by operating the MF, it is desirable that the AF is not automatically restarted after the MF operation as in Patent Document 2. However, which mode the operator desires varies depending on the actual shooting situation, and thus either mode may be advantageous or disadvantageous.

  The present invention has been made in view of such circumstances. When priority is given to MF operation even during AF control, a special operation is performed to determine whether or not focus adjustment by AF control is effectively resumed after MF operation. An object of the present invention is to provide an autofocus system that allows an operator to easily select according to the situation without performing the operation.

In order to achieve the above object, the autofocus system according to claim 1 includes a photographing optical system that forms an image of a subject, an imaging unit that picks up an image formed by the photographing optical system, and the photographing. A focus adjustment lens group disposed in the optical system, the focus lens group disposed to be movable back and forth along the optical axis, and a focus lens group driving unit for electrically driving the focus lens group; A manual operation member capable of manual operation, an operation position detection means for detecting an operation position of the manual operation member, an operation member drive means for electrically driving the manual operation member, and detected by the operation position detection means A focus lens that moves the focus lens group to a position corresponding to the operated position by the focus lens group driving means. A group control unit, and the focus evaluation value detecting means for detecting a focus evaluation value indicating the contrast level of an image obtained by the imaging unit, by the focusing lens group control unit on the basis of the operating position of the manual operation member so that the position of the focus lens group moving is focus position, the operating member a control driven by the operating member driving means before Symbol manual operation member on the basis of the focus evaluation value detected by the focus evaluation value detecting means Means.

  According to the present invention, the manual operation member used for the manual focus (MF) is electrically driven even when the auto focus (AF) control for moving the focus lens group to the in-focus position based on the focus evaluation value is performed. The focus lens group is moved to a position corresponding to the operation position. Accordingly, even during AF control, when the operator operates the manual operation member, the focus lens group moves according to the operation of the MF. In other words, this is a system that realizes an AF mode with priority on MF. On the other hand, when the operation of the manual operation member is stopped, if the position of the focus lens group at that time is to be maintained, the operation position of the manual operation member is maintained as it is (fixed by hand) and the manual operation is performed for AF control. It is only necessary to prevent the member from being driven. Conversely, if it is desired to execute AF control, the manual operation member may be allowed to be driven for AF control (such as releasing the manual operation member). Accordingly, whether or not AF control is effectively restarted after the MF operation can be selected depending on the situation, and the selection also determines whether or not the force to operate the manual operation member (whether or not to prevent the manual operation member from moving) is selected. This can be done easily by adjusting the force.

  Further, according to the present invention, even when the focus adjustment is performed with the manual operation member by MF, the force is applied to the manual operation member to perform the focus adjustment by the AF control. By operating the MF while sensing, the AF can be used as an assist for focus adjustment by the MF.

  According to a second aspect of the present invention, in the invention of the first aspect, the operation position detecting means is means for detecting an absolute position of the manual operation member.

  According to the first aspect of the present invention, the operation position of the manual operation member and the position of the focus lens group change in conjunction with each other even during AF control. Even when the operation position of the manual operation member is detected using a position sensor that detects the absolute position, the difference between the position of the focus lens group corresponding to the operation position of the manual operation member and the actual position of the focus lens group Does not occur, and the problem that the focus lens group moves to a separated position when switching from AF to MF does not occur. Further, an end (mechanical end) is provided in the movable range of the manual operation member, and the end and the movable end of the focus lens group can correspond to each other, so that the operator has reached the end of the manual operation member. It is easy to know that the focus lens group has reached the end.

  According to a third aspect of the present invention, in the invention according to the first or second aspect, the manual operation member is a rotation operation member provided in a controller for manually operating the focus lens group remotely. It is characterized by that. The present invention shows a specific mode of a manual operation member, and shows a mode in which a rotation operation member such as a focus knob provided in a controller called a so-called focus demand is used as a manual operation member.

  According to a fourth aspect of the present invention, in the invention of the third aspect, the focus evaluation value detecting means is provided in the controller. Usually, a focus evaluation value detection means is mounted on a lens apparatus having a photographing optical system and its control system, but in the present invention, a controller is provided. As a result, it becomes unnecessary to transmit information related to driving of the manual operation member to the controller.

  The autofocus system according to claim 5 is the invention according to any one of claims 1 to 4, wherein the operating member driving means includes a motor that generates a driving force for driving the manual operating member; 5. A torque limiter for connecting the motor and the manual operation member and for limiting the torque generated by the motor so as not to exceed a predetermined magnitude. The autofocus system according to 1.

  According to the present invention, when the manual operation member is driven for AF control, even if the operator operates the manual operation member, the torque limiter restricts the motor torque from increasing. Therefore, the motor and related circuits can be prevented from being damaged, and the manual operation member can be easily operated.

  An autofocus system according to a sixth aspect is the invention according to any one of the first to fifth aspects, wherein an autofocus mode in which the focus lens group is automatically moved to a focus position, and the focus lens group is Mode switching means for switching between manual focus modes to be moved by operation of the manual operation member, and the operation member control means is operated by the operation member drive means when the autofocus mode is selected by the mode switching means. The drive of the manual operation member is validated, and when the manual focus mode is selected by the mode switching means, the drive of the manual operation member by the operation member drive means is invalidated.

  According to the present invention, in addition to the MF-priority AF mode as described in claim 1 and the like, it is also possible to select an MF mode in which focus adjustment is performed only by MF operation using a manual operation member.

  According to the autofocus system of the present invention, when priority is given to MF operation even during AF control, whether or not focus adjustment by AF control is effectively resumed after MF operation is performed without performing a special operation. The operator can easily select according to the situation

  Hereinafter, preferred embodiments of 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 overall configuration of a lens system to which the present invention is applied. The lens system shown in the figure is a system used for a television camera for broadcasting, for example, and includes a photographing lens (optical system) and a control system.

  The photographing lens includes a focus lens (group) FL that moves in the optical axis direction for focus adjustment in the lens barrel, and a zoom lens (group) ZL that moves in the optical axis direction for zoom adjustment (focal length adjustment). A diaphragm I that opens and closes to adjust the amount of light, and other fixed lens groups are disposed.

  The subject light incident on the photographic lens is imaged on the imaging surface (imaging surface) of the imaging element (not shown) of the camera body (camera head) that is mounted with the photographic lens, and after photoelectric conversion by the imaging element, the camera body Predetermined signal processing is performed by the internal signal processing unit. As a result, a video (subject image) captured by the image sensor via the photographing lens can be obtained by the camera body as a video signal of a predetermined format (for example, NTSC system).

  The focus lens FL, the zoom lens ZL, and the aperture stop I are respectively connected with a focus motor FM, a zoom motor ZM, and an aperture motor IM, which are respectively connected to the focus lens FL and the zoom motor ZM. The zoom lens ZL is driven in the optical axis direction, and the diaphragm I is driven to open and close. The motors FM, ZM, and IM rotate in accordance with the voltage values of drive signals supplied from the CPU 16 to the focus amplifier FA, the zoom amplifier ZA, and the aperture amplifier IA via the D / A converter 18, respectively. Controlled by speed.

  The CPU 16 is provided with an instruction signal indicating a position (target position) or speed (target speed) to be set for the focus lens FL or the zoom lens ZL from a controller such as the focus demand 10 or the zoom demand 12. Here, in the present embodiment, the components other than the focus demand 10 and the zoom demand 12 shown in FIG. 1 are components mounted on an integrally configured lens device. The zoom demand 12 is assumed to be a separate device from the lens device connected to the lens device by a cable. However, what kind of device configuration the system is constructed in and where each component of FIG. 1 is arranged in each device are not limited to a specific mode.

  Although the configuration of the focus demand 10 will be described later, the CPU 50 is mounted on the focus demand 10, and various signals are transmitted by serial communication between the serial communication interface (SCI) 50A of the CPU 50 and the SCI 16A of the CPU 16 of the lens apparatus. You can send and receive. The instruction signal given from the focus demand 10 to the CPU 16 is transmitted by serial communication performed between the SCI 50A and the SCI 16A. On the other hand, the instruction signal output from the zoom demand 12 is an analog signal, and is given to the CPU 16 after being converted into a digital signal by the A / D converter 14.

  The CPU 16 controls the rotation speeds of the focus motor FM and the zoom motor ZM by changing the values of the drive signals output to the focus amplifier FA and the zoom amplifier ZA, and the focus lens FL and the zoom lens ZL The positions and speeds of the focus lens FL and the zoom lens ZL are controlled so that the target position or target speed instructed by the instruction signals from the focus demand 10 and the zoom demand 12, respectively. The CPU 16 is provided with a position signal indicating the current position of the focus lens FL from the focus potentiometer FP via the A / D converter 14, and a position signal indicating the current position of the zoom lens ZL. It is given from the meter ZP via the A / D converter 14. When the instruction signal for the focus lens FL or the zoom lens ZL specifies a target position, the target lens and the current position of the focus lens FL or the zoom lens ZL are sequentially compared, and the focus lens FL or the zoom lens ZL is sequentially compared. A driving signal having a value such that the operation speed of the zoom lens ZL becomes a speed corresponding to the difference between the target position and the current position (a speed that decreases as the difference decreases) becomes a focus amplifier FA. Alternatively, the signal is output to the zoom amplifier ZA.

  As for the aperture I, generally, an instruction signal for instructing the position (aperture value) at which the aperture I should be set is given from the camera body to the CPU 16, and the CPU 16 uses the position signal indicating the current position (opening / closing degree) of the aperture I for the aperture. The iris motor IM is controlled while being detected by the potentiometer IM, and the iris I is controlled so that the iris value specified by the instruction signal is obtained.

  Further, as shown in the figure, a processing unit shown as a focus evaluation value detection unit 30 is provided in the lens device on which the CPU 16 is mounted. The focus evaluation value detection unit 30 acquires a video signal obtained from the image sensor of the camera body from the camera body, and detects a focus evaluation value indicating the contrast level of the currently captured image (captured image). The focus evaluation value detected by the focus evaluation value detection unit 30 is given to the CPU 16.

  During the AF control (AF mode), the CPU 16 controls the focus lens FL based on the focus evaluation values sequentially obtained from the focus evaluation value detection unit 30, and focuses the position where the focus evaluation value is maximized (maximum). As a position, the focus lens FL is set at the in-focus position. This automatically adjusts the focus. However, as described later, the CPU 16 does not directly control the focus lens FL based on the focus evaluation value obtained from the focus evaluation value detection unit 30, but controls it through the focus demand 10.

  Here, the configuration of the focus evaluation value detection unit 30 will be described. The focus evaluation value detection unit 30 mainly includes an A / D converter 32, a high-pass filter (HPF) 34, a gate circuit 36, and an addition circuit 38. The A / D converter 32 receives a video signal (luminance signal) from the camera body. From the video signal converted into a digital signal by the A / D converter 32, only a high frequency component is extracted by a high pass filter (HPF) 34 and then input to the gate circuit 36. Then, the gate circuit 36 extracts a signal only within a predetermined AF area (for example, a rectangular area at the center of the screen) set within the shooting range (view angle range). Note that a video signal is directly given to the gate circuit 36, and a signal range corresponding to the AF area in each field is specified by referring to the synchronization signal of the video signal.

  The signal of the high frequency component in the AF area extracted by the gate circuit 36 is integrated by the addition circuit 38 for each field, and the integrated value is output to the CPU 16 as a focus evaluation value. Note that the processing content and processing method for detecting the focus evaluation value from the captured image are not limited to those shown here.

  Next, control of the focus lens FL (focus control) in the lens system will be described in detail. A device for constructing the lens system, for example, the focus demand 10 or the case portion of the lens device, is provided with a predetermined mode change switch (not shown), and the mode change switch enables the MF mode and the AF mode. Can be switched.

  When the MF mode is selected by the mode switch, the focus lens FL is controlled by the operation of the MF using the focus knob 52 that is a rotation operation member provided in the focus demand 10.

  As shown in FIG. 2, in the focus demand 10, a rotation shaft 62 is rotatably supported on a side portion of the demand main body 60, and a focus knob 52 is fixed to the rotation shaft 62 with screws 64 and 64. Yes. In addition, a detection shaft 66 of a potentiometer 54 fixed inside the demand main body 60 is connected to the rotation shaft 62 via a connecting member 68. As a result, the detection shaft 66 of the potentiometer 54 rotates as the focus knob 52 rotates, and a voltage signal corresponding to the rotational position of the focus knob 52 is output from the potentiometer 54. In FIG. 1, components of the focus demand 10 are shown in the block of the focus demand 10. As shown in FIG. 1, the focus demand 10 includes a CPU 50 and an A / D converter 56 omitted in FIG. 2 in addition to the focus knob 52 and the potentiometer 54 shown in FIG. 2, and is connected to the focus knob 52. The voltage signal output from the potentiometer 54 is converted into a digital signal by the A / D converter 56, and the value is read by the CPU 50. In the MF mode, the CPU 50 sets a value of an instruction signal indicating the target position of the focus lens FL corresponding to the value of the voltage signal read from the potentiometer 54, and sends the instruction signal of that value to the CPU 16 of the lens apparatus by the SCI 50A. Send. On the other hand, the CPU 16 of the lens device controls the position of the focus lens FL so as to be the target position specified by the instruction signal given as described above. As a result, the focus lens FL is moved to a position corresponding to the rotational position of the focus knob 52 that is manually operated by the operator.

  When the AF mode is selected by the mode changeover switch, the focus evaluation value is maximized (maximum) based on the focus evaluation value detected by the focus evaluation value detection unit 30 shown in FIG. The focus lens FL is controlled so as to move to the in-focus position where the contrast of the subject image in the AF area becomes maximum (maximum).

  An outline of a case where a so-called hill-climbing method is used as a method for moving the focus lens FL to a position where the focus evaluation value is maximized will be described. First, in this method, the focus lens FL is first set to a position (start point). A small amount is displaced in the back-and-forth direction along the optical axis from the (position) (wobbling), and a focus evaluation value at each displacement point in the meantime is acquired. Then, by comparing the magnitude of the focus evaluation value at each displacement point, it is detected whether or not the focus evaluation value at the start position of the focus lens FL is the maximum, and the direction in which the focus evaluation value increases when it is not the maximum is detected. To detect.

  When the focus evaluation value is the maximum, the starting point position is the in-focus position, and the focus lens FL is stopped at the starting point position. On the other hand, when the focus evaluation value is not the maximum, the focus lens FL is moved at a constant amount or a constant speed in a direction in which the focus evaluation value increases. Then, the above processing is repeated at predetermined time intervals. As a result, the focus lens FL moves to the focus position where the focus evaluation value is maximized, and stops at the focus position. When detecting the direction in which the focus evaluation value increases and moving the focus lens in that direction, the focus evaluation value is detected while detecting the position where the focus evaluation value does not increase, and the focus lens is detected at that position. By stopping the FL, it is possible to eliminate the need for detecting the increasing direction of the focus evaluation value by wobbling during that period (no wobbling is required). Further, methods other than those described above may be used as a method of moving the focus lens to a position where the focus evaluation value is maximized.

  The CPU 16 of the lens apparatus sequentially determines the target position or target speed for operating the focus lens FL as described above so that the focus evaluation value acquired from the focus evaluation value detection unit 30 is maximized. Then, instead of directly controlling the focus lens FL according to the sequentially determined target position or target speed, an instruction signal having a value indicating the target position or target speed of the focus lens FL is sent to the CPU 50 of the focus demand 10 by serial communication using the SCI 16A. Send.

  Although the details will be described later, the focus knob 52 of the focus demand 10 is driven by a motor 58, and the CPU 50 determines the target position or target speed of the focus lens FL instructed by an instruction signal from the CPU 16 of the lens apparatus. A drive signal is given to the motor 58 via the D / A converter 60 so that the focus knob 52 rotates at the rotation position corresponding to the value or at the rotation speed.

  For example, when the instruction signal given from the CPU 16 of the lens apparatus is a value indicating the target position, the current rotational position of the focus knob 52 obtained from the potentiometer 54 is set with the rotational position corresponding to the target position as the target rotational position. The motor 58 is driven at a speed corresponding to the difference between the two and the speed (the smaller the difference is, the slower the speed is). When the instruction signal given from the CPU 50 is a value indicating the target speed, the rotational speed corresponding to the target speed is set as the target rotational speed, and the motor 58 is operated at a rotational speed at which the focus knob 52 becomes the target rotational speed. To drive. Even if the instruction signal given from the CPU 16 indicates the target speed, the rotational speed of the focus knob 52 is controlled by position control by appropriately changing the target rotational position so that the rotational speed corresponds to the target speed. Can also be controlled.

  Here, the configuration of the focus demand 10 in which the focus knob 52 can be driven by the motor 58 will be described. In the focus demand 10 shown in FIG. 2, a gear portion 80 is formed in the circumferential direction of the outer wall of the rotary shaft 62. A motor 58 fixed in the demand main body 60 is connected to the gear unit 80 via a torque limiter 82. The torque limiter 82 shown in the figure includes an inner ring 84 and an outer ring 86. The inner ring 84 and the outer ring 86 rotate relatively while sliding, and the outer ring 86 is pressed against the flange portion 84A of the inner ring 84 by a coil spring 88. It has become so. One end of the coil spring 88 is fixed to a presser plate 90 attached to the inner ring 84. With respect to such a torque limiter 82, the rotating shaft 92 of the motor 58 is fixed in the hollow of the inner ring 84 of the torque limiter 82, and the gear portion 80 of the rotating shaft 62 is engaged with the gear portion 87 of the outer ring 86. Yes.

  As a result, the focus knob 52 is driven by the motor 58 via the torque limiter 82. Even when the operator performs an operation different from the operation of the motor 58 on the focus knob 52, the inner ring 84 and the outer ring 86 of the torque limiter 82 slide when the torque of the motor 58 exceeds a certain level. Accordingly, the motor 58 and related circuits are protected, and the manual operation of the focus knob 52 is facilitated.

  In FIG. 1, the CPU 50 of the focus demand 10 drives the focus knob 52 by the motor 58 according to the instruction signal given from the CPU 16 of the lens apparatus as described above, and the rotational position of the focus knob 52 as in the MF mode. Is detected by the potentiometer 54, and an instruction signal having a value corresponding to the detected rotational position of the focus knob 52 is transmitted to the CPU 16 of the lens apparatus by serial communication using the SCI 50A. The CPU 16 of the lens apparatus controls the focus motor FM so that the focus lens FL moves to the target position designated by the instruction signal given from the focus demand 10 as in the MF mode.

  According to the control in the AF mode as described above, when the focus knob 52 rotates according to the target position or target speed given to the focus demand 10 from the CPU 16 of the lens apparatus, the focus lens FL is moved by the CPU 16. It behaves exactly as if it were directly controlled. That is, the focus lens FL moves to the in-focus position by AF control. On the other hand, when the operator performs an operation on the focus knob FL that is different from the operation by the motor 58, the rotation position of the focus knob 52 is changed by the operation of the operator and corresponds to the rotation position. The focus lens FL moves to the position. Accordingly, the AF mode of the present embodiment is an MF priority AF mode in which the MF operation is prioritized when the operator operates the focus knob 52 (MF operation). At this time, the operator can set the focus lens FL to a desired position by adjusting the rotational position of the focus knob 52 by manual operation.

  In such an AF mode, after the focus knob 52 is manually operated to move the focus lens FL to a desired position, the operator manually operates the focus knob 52 so that the focus knob 52 is not rotated by the motor 58. If the position is held, the position of the focus lens FL moved by manual operation can be held. On the other hand, if the focus knob 52 is manually operated to move the focus lens FL to a desired position, and the operator permits the motor 58 to drive the focus knob 2 by releasing the hand from the focus knob 52, the focus is adjusted. After manual operation with the knob 52, focus adjustment by AF control can be resumed immediately. Therefore, any mode can be selected easily after manual operation of the focus knob 52.

  Further, since the rotational position of the focus knob 52 and the position of the focus lens FL change in conjunction with the AF control, the rotational position of the focus knob 52 can be detected by the potentiometer 54 that detects the absolute position. Further, an end for limiting the rotation range of the focus knob 52 can be provided at the rotation position of the focus knob 52 corresponding to the positions of the close end and the infinity end of the focus lens FL. In FIG. 2, a projection 96 is formed on the rotary shaft 62 to which the focus knob 52 is fixed, and a pin 98 is projected inside the demand main body 60, and the projection 96 of the rotary shaft 62 is formed on the pin 98. When the contact is made, the rotation of the focus knob 52 is restricted, and the rotation position at that time is set as the end of the focus knob 52. In this way, if the focus knob 52 is also provided with an end in accordance with the end of the movable range of the focus lens FL, when the focus lens FL is adjusted using the focus knob 52, the focus lens FL is at the end. You can be sure that you have reached it. However, it is not always necessary to use a potentiometer to detect the rotational position of the focus knob 52, and other types of position sensors such as an encoder may be used. In addition, since there is no difference between the position of the focus lens FL corresponding to the rotation position of the focus knob 52 and the actual position of the focus lens FL, the focus lens FL is separated from the position when the AF control is switched to the MF control. The trouble of moving does not occur.

  Next, other configuration examples of the lens system capable of realizing the same focus control as in the above embodiment are shown in FIGS. 3 to 5 show only the configuration related to the exchange of signals among the CPU 16, the focus evaluation value detection unit 30 and the focus demand 10 of the lens apparatus in FIG. 1, and other components are shown in FIG. It is omitted because it matches. Moreover, in the structure of each figure, the same code | symbol is attached | subjected about the component of the same or similar action as FIG. 1, and description is abbreviate | omitted.

  In the form shown in FIG. 3, the form of signal transmission between the CPU 16 of the lens apparatus and the CPU 50 of the focus demand 10 is different from the form of FIG. 1, and the analog signal is transmitted between the lens apparatus and the focus demand 10. Shows when to do. For example, the value of the instruction signal related to driving of the focus knob 52 transmitted from the CPU 16 to the CPU 50 of the focus demand 10 is output as a digital signal from the CPU 16 and converted into an analog signal by the D / A converter 100. The analog signal is transmitted to the focus demand 10 through a cable. The analog signal transmitted to the focus demand 10 is converted into a digital signal by the A / D converter 102 and read into the CPU 50.

  On the other hand, for example, the value of an instruction signal (instruction signal indicating a target position corresponding to the rotation position of the focus knob 52) relating to driving of the focus lens FL transmitted from the CPU 50 of the focus demand 10 to the CPU 16 is output from the CPU 50 as a digital signal. Then, it is converted into an analog signal by the D / A converter 104. The analog signal is transmitted to the lens device through a cable. The analog signal transmitted to the lens device is converted into a digital signal by the A / D converter 106 and read into the CPU 16. As described above, the exchange of signals between the CPU 16 of the lens device and the CPU 50 of the focus demand 10 is not limited to serial communication as shown in FIG.

  In the form shown in FIG. 4, the focus evaluation value detection unit 30 is mounted on the focus demand 10 instead of the lens device, and the focus evaluation value detected by the focus evaluation value detection unit 30 is given to the CPU 16 of the lens device. 1 in that it is given to the CPU 50 of the focus demand 10. In FIG. 4, the target position or target speed of the focus knob 52 for operating the focus lens FL so that the focus evaluation value is maximized is determined based on the focus evaluation value acquired from the focus evaluation value detection unit 30. The ten CPUs 50 sequentially determine and drive the motor 58 based on the determination. Accordingly, it is not necessary to obtain an instruction signal related to driving of the focus knob 52 from the CPU 16 of the lens apparatus as shown in FIG. 1, and an instruction signal related to driving of the focus lens FL is mainly sent from the CPU 50 of the focus demand 10 to the CPU 16 of the lens apparatus. Is sent.

  In the form shown in FIG. 5, the signal transmission between the lens apparatus and the focus demand 10 is performed by an analog signal as in the form of FIG. 3, and the focus evaluation value unit 30 is in focus focus as in the form of FIG. 10 and the focus evaluation value detected by the focus evaluation value detection unit 30 is given to the CPU 50 of the focus demand 10. In the aspect of FIG. 5, it is not necessary to obtain an instruction signal related to the driving of the focus knob 52 from the CPU 16 of the lens apparatus as in the aspect of FIG. 4, and therefore the instruction signal related to the driving of the focus lens FL from the CPU 50 of the focus demand 10. Are transmitted to the CPU 16 of the lens apparatus by analog signals. Other configurations and processes different from those in FIG. 1 are the same as the contents described in FIG. 3 or FIG.

  In the embodiment described above, the wobbling operation for detecting the direction in which the focus evaluation value increases is also performed by driving the focus knob 52 of the focus demand 10, but the wobbling is driven by the focus knob 52. Instead, the focus lens FL may be driven directly.

  In the above embodiment, the focus knob 52 is rotated based on the focus evaluation value obtained from the focus evaluation value detection unit 30 during AF control, and corresponds to the rotational position of the focus knob 52 detected by the potentiometer 54. Although the focus lens FL is moved to the position, the focus lens FL is directly moved based on the focus evaluation value obtained from the focus evaluation value detection unit 30 during the AF control, and corresponds to the position of the focus lens FL. Even when the focus knob 52 is rotated so as to be in the rotation position, there is an effect. In this case as well, since the rotational position of the focus knob 52 changes in conjunction with the position of the focus lens FL, a potentiometer can be used to detect the rotational position of the focus knob 52, and it is infinite with the closest end of the focus lens FL. An end for limiting the rotation range of the focus knob 52 can be provided corresponding to the far end.

  Further, the operation member when performing focus adjustment by MF may be an operation member other than the rotation operation member such as the focus knob 52.

FIG. 1 is a block diagram showing the overall configuration of a lens system to which the present invention is applied. FIG. 2 is a cross-sectional view showing the configuration of the focus demand. FIG. 3 is a diagram showing another configuration example of the lens system to which the present invention is applied. FIG. 4 is a diagram showing another configuration example of the lens system to which the present invention is applied. FIG. 5 is a diagram showing another configuration example of the lens system to which the present invention is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Focus demand, 14 ... A / D converter, 16, 50 ... CPU, 18 ... D / A converter, 30 ... Focus evaluation value detection part, 16A, 50A ... Serial communication interface (SCI), 52 ... Focus knob , 52 ... Motor, 54 ... Potentiometer, 60 ... Demand body, 62 ... Rotating shaft, FL ... Focus lens, ZL ... Zoom lens, I ... Aperture, FM ... Focusing motor, FP ... Focus potentiometer, 82 ... Torque limiter

Claims (6)

A photographic optical system that forms an image of a subject;
Imaging means for capturing an image formed by the imaging optical system;
A lens group for focus adjustment arranged in the photographing optical system, the focus lens group arranged to be movable back and forth along the optical axis;
A focus lens group driving means for electrically driving the focus lens group;
A manual operation member capable of manual operation;
An operation position detecting means for detecting an operation position of the manual operation member;
Operation member driving means for electrically driving the manual operation member;
Focus lens group control means for moving the focus lens group by the focus lens group driving means to a position corresponding to the operation position detected by the operation position detection means;
A focus evaluation value detecting means for detecting a focus evaluation value indicating the height of contrast of an image obtained by the imaging means;
The way that the position of the focus lens group is a focusing position based on the focus evaluation value detected by the focus evaluation value detection means for said moving the focus lens group control unit on the basis of the operating position of the manual operation member an operating member control means for the pre-Symbol manual operation member is driven by the operating member driving means,
An autofocus system characterized by comprising   2. The autofocus system according to claim 1, wherein the operation position detecting means is means for detecting an absolute position of the manual operation member.   3. The autofocus system according to claim 1, wherein the manual operation member is a rotation operation member provided in a controller for manually operating the focus lens group remotely.   4. The autofocus system according to claim 3, wherein the focus evaluation value detection means is provided in the controller.   The operating member driving means connects a motor that generates a driving force for driving the manual operating member, the motor and the manual operating member, and the torque generated by the motor does not exceed a predetermined magnitude. The autofocus system according to any one of claims 1 to 4, further comprising a torque limiter for limiting.   A mode switching unit that switches between an auto focus mode that automatically moves the focus lens group to a focus position and a manual focus mode that moves the focus lens group by operating the manual operation member; When the auto-focus mode is selected by the mode switching means, the manual operation member is driven by the operation member driving means, and when the manual focus mode is selected by the mode switching means, The autofocus system according to any one of claims 1 to 5, wherein driving of the manual operation member by the operation member driving unit is invalidated.

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