JP2003241074A - Automatic focusing device and camera system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform automatic focusing at a high speed. <P>SOLUTION: An automatic focusing device is provided with a 1st coarse- adjustment actuator and a 2nd fine-adjustment actuator and a focusing state discriminating means for discriminating the focusing state, and a member to be focused on is moved with the drive of the 1st actuator toward a focal position in a period until it is discriminated by the focusing state discriminating means that the member to be focused on passes through the focal position (#105 to #111), and based on the discrimination that the member has passed through the focal position, the member to be focused on being driven by the 1st actuator is stopped, and also, the member to be focused on starts to move with the drive of the 2nd actuator in a direction opposite to the driving direction of the 1st actuator, thereafter, the driving direction of the 2nd actuator and the driving finish of the 2nd actuator are determined based on the output of the focusing state discriminating means (#112 to #120). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvements in an automatic focusing device and a camera system used for autofocusing a digital still camera, a video camera or the like.

[0002]

2. Description of the Related Art Conventionally, in an autofocus mechanism of an interchangeable lens type autofocus single-lens reflex camera using a silver salt film, autofocus or the like based on a TTL phase difference has been adopted. This autofocus mechanism
A defocus detection mechanism for autofocus is provided in the camera body, and the focus lens on the interchangeable lens side is driven by a motor in the lens or in the camera body to perform focus adjustment operation.

Further, in a video camera or the like, so-called hill-climbing AF (autofocus) is performed in which the contrast is detected by the high frequency component of the signal from the image pickup device.

The above-mentioned autofocus based on the TTL phase difference and autofocus based on the contrast detection have their respective characteristics, and are used properly according to the intended use.

In Japanese Laid-Open Patent Publication No. 5-64056, the defocus direction and the defocus amount cannot be known by one focus detection only by the autofocus by contrast detection. Therefore, the autofocus by contrast detection and the TTL phase difference are detected. A technique for performing a combination of autofocus is disclosed.

According to Japanese Patent No. 2893727,
In autofocusing by contrast detection, a technique is disclosed in which after passing a contrast peak, the focus lens is returned while performing a wobbling operation to obtain a focus position.

Further, Japanese Patent Application Laid-Open No. 7-284502 discloses a technique of manual focus adjustment of a microscope for smoothly performing coarse and fine adjustments by linking a means for performing high-speed coarse adjustment and a means for performing low-speed fine adjustment. ing.

[0008]

However, each of the above-mentioned conventional examples has the following drawbacks, and it is difficult to perform focus adjustment at high speed and with high accuracy. (1) Although it is unavoidable that a reversing operation occurs during autofocusing by contrast detection, it is difficult to stop the focus lens with high accuracy due to the influence of backlash. (2) In the technology according to Japanese Patent No. 2893727, since it is entirely covered by the actuator capable of high-precision control, it is not suitable for high-speed driving, and it is difficult to focus at high speed from a large defocus time. Met. (3) Japanese Patent Application Laid-Open No. 7-284502 only discloses the technical contents of performing coarse and fine adjustment of the manual focus of a microscope, and autofocus, which is a technique different from the manual focus and is applied to the camera. There is no disclosure of how to coordinate.

(Object of the Invention) A first object of the present invention is to confirm a focus position during high-speed coarse adjustment, and then perform a final focus operation with a second actuator for fine adjustment to perform a search during fine adjustment. It is an object of the present invention to provide an automatic focus adjustment device capable of performing high-speed automatic focus adjustment by limiting the range and the direction.

A second object of the present invention is to perform automatic focus adjustment at a higher speed by partially overlapping the driving of the first focused member and the second focused member. It is intended to provide a device.

A third object of the present invention is to provide an automatic focusing device which can simplify the structure by integrating the first focused member and the second focused member. is there.

A fourth object of the present invention is to provide an automatic focus adjusting device which can be optimized according to the type of interchangeable lens.

A fifth object of the present invention is to provide an automatic focusing apparatus which can obtain a highly accurate focusing accuracy by detecting a contrast.

A sixth object of the present invention is to use both of the automatic focus adjustment based on the phase difference and the automatic focus adjustment based on the contrast detection to prevent false focusing due to the automatic focus adjustment based on the contrast detection. It is intended to provide a focus adjustment device.

A seventh object of the present invention is to provide a camera system capable of optimizing adjustment according to the contents of movement.

An eighth object of the present invention is to provide a camera system which can reduce the cost of the total camera system.

[0017]

In order to achieve the above-mentioned first object, the invention according to claim 1 has a first actuator for coarse adjustment which is a drive source for focus adjustment, and a first actuator for focus adjustment. A second actuator for fine adjustment which is a drive source,
In an automatic focus adjustment device having a focus state determination means for determining a focus state, a period until it is determined that the focused member has passed the focus position in the focus state determination means,
The driven member is moved in the direction of the focusing position by the driving by the first actuator, and when it is determined that the focusing member has passed, the driving by the first actuator is stopped and The movement of the focused member is started by the driving of the second actuator in the direction opposite to the driving direction of the first actuator, and then the second actuator is driven based on the output of the focusing state determination means. The automatic focus adjustment device determines the direction and the end of driving.

Further, in order to achieve the above second object,
According to a second aspect of the present invention, the focused member includes a first focused member and a second focused member, and the first focused member is the first for coarse adjustment. The second in-focus member is moved by the drive of the second actuator for fine adjustment,
The automatic focusing apparatus according to claim 1, wherein the first actuator and the second actuator have timings to be simultaneously driven.

Further, in order to achieve the third object,
According to a third aspect of the invention, the focus lens barrel having the focusing lens therein is the first focused member, and the focusing lens configured to be movable in the focus lens barrel is the second focusing lens. The automatic focusing device according to claim 2, which is the in-focus member.

In order to achieve the above-mentioned fourth object,
The invention according to claim 4 is characterized in that the first focused member is a focusing lens, and the second focused member is an image recording medium. This is the automatic focus adjustment device.

Further, in order to achieve the fifth object,
According to a fifth aspect of the present invention, there is provided a focus state determination unit that evaluates the focus state by determining contrast based on a signal from an image capturing unit that captures light from a subject and converts it into an electric signal. The automatic focus adjusting device according to any one of 1 to 4.

In order to achieve the sixth object,
According to a sixth aspect of the present invention, the in-focus state determining means evaluates the in-focus state by determining the contrast based on a signal from an image capturing means that captures light from a subject and converts it into an electric signal. The first focusing state determining means and the second focusing state determining means for calculating the defocus amount based on the phase difference to evaluate the focusing state, the first focusing state determining means and the first focusing state determining means. The automatic focus adjusting device according to any one of claims 1 to 5, wherein it is determined that the in-focus member has passed the in-focus position based on both outputs of the in-focus state determining means. is there.

In order to achieve the seventh object,
The invention described in claim 7 is a camera system including an interchangeable lens and a camera body, which has the automatic focusing apparatus according to claim 2 or 3, wherein the first focused member and the first focused member The second focused member, the first actuator, and the second actuator are built in the interchangeable lens, and the focusing state determination means is a camera system built in the camera body side. .

In order to achieve the eighth object,
The invention described in claim 8 is a camera system including the interchangeable lens and the camera body, which has the automatic focus adjustment device according to claim 2 or 4, wherein the first focused member and the first focused member The first actuator is built in the interchangeable lens, and the second focused member, the second actuator, and the focusing state determination means are a camera system built in the camera body side. .

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail based on the illustrated embodiments.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
2 is a block diagram showing an electrical configuration according to the embodiment of the present invention, showing an example applied to a lens interchangeable digital still camera. FIG.

In FIG. 1, 1 is a digital still camera body, and 2 is an interchangeable lens.

First, on the interchangeable lens 2 side, 3 is a focus lens, and 4 is a second actuator for adjusting the focus lens 3 in the optical axis direction. Whichever of the second second actuator and the focus lens 3 is used. Is also held by the focus lens barrel 5. The focus lens 3 is adjusted relative to the focus lens barrel 5 in the optical axis direction by the second actuator 4. Reference numeral 6 denotes a first actuator, which adjusts the focus lens barrel 5 in the optical axis direction.

With the above arrangement, the focus lens 3 is
The position is adjusted by both the first and second actuators 6 and 4. In detail, the fine adjustment of the focus lens 3 is performed by the second actuator 4, and the coarse adjustment is performed by the first actuator 6.

Reference numeral 7 denotes a lens control circuit, which has a function of communicating with the digital still camera body 1 and controlling the second actuator 4 and the first actuator 6 respectively.

Next, the digital still camera body 1 side will be described.

Reference numeral 8 is a half mirror, 9 is an image pickup element, and 10 is a sensor for phase difference AF. The half mirror 8 is
It has a function of splitting the imaging light flux into the image sensor 9 and the phase difference AF sensor 10, and with this configuration, it is possible to perform the imaging operation and the autofocus operation based on the phase difference at the same time.

Reference numeral 11 denotes an LCD panel for an electronic viewfinder, which has a built-in backlight. A finder optical system 12 allows the LCD panel 11 to be observed through the finder optical system 12. 13 is the first
Is a focus evaluation circuit for calculating the amount of defocus (day focus) from a signal from the sensor 10 for phase difference AF.
An image processing circuit 14 processes the output signal of the image pickup device 9 and extracts the contrast information of the image, and also performs white balance, γ processing, color matrix processing and the like to form a photographed image and an image for a finder.

The image for the finder formed by the image processing circuit 14 is sent to the LCD panel 11 and the LC
It is displayed on the D panel 11. Then, the image for the finder is provided to the photographer for observation through the finder optical system 12.

A second focus evaluation circuit 15 outputs a focus evaluation value by determining the history of contrast information obtained from the image processing circuit 14. A camera control circuit 16 controls the entire digital still camera body 1. A lens interface circuit 17 exchanges signals with the lens control circuit 7 provided on the interchangeable lens 2 side. Reference numeral 18 is a release switch. The captured image is stored in a nonvolatile memory or the like (not shown).

The operation of the digital still camera having the above configuration will be described with reference to the flowchart of FIG.

When a power source (not shown) is turned on, first, in step # 101, the camera control circuit 16 starts an initialization operation and sends an initial reset command to the lens control circuit 7 via the lens interface circuit 17. . Upon receiving the initial reset command, the lens control circuit 7 moves the focus lens 3 to a predetermined position of the focus lens barrel 5 by the second actuator 4. In this embodiment, the focus lens 3 is set at the center position.

In the next step # 102, the release switch 18 is half-depressed (S1 is turned on), and the process waits until an instruction for shooting preparation is given. After that, when the release switch 18 is pressed halfway to give an instruction for shooting preparation, step # 103
To proceed to obtain a signal from the phase difference AF sensor 10,
The defocus amount is calculated by the first focus evaluation circuit 13. In the following step # 104, the lens drive amount necessary for focusing is calculated from the obtained defocus amount, and the drive amount is corrected. Specifically, a correction for subtracting a predetermined value from the lens drive amount is performed to generate a corrected drive amount. The correction drive amount obtained here is data for setting the lens to be driven before the detection error of the phase difference AF. Therefore, the predetermined value is the type of the interchangeable lens 2, the focus position, and the zoom position. It is desirable to make it different depending on the situation, and it can be easily determined by receiving and generating information from the interchangeable lens 2 side.

Next, proceeding to step # 105, the camera control circuit 16 sends the correction drive amount to the lens control circuit 7 on the interchangeable lens 2 side via the lens interface circuit 17. Then, the lens control circuit 7 starts driving (coarse adjustment) of the focus lens barrel 5 by the first actuator 6. Then, in the next step # 106, it is determined whether or not the driving for the correction driving amount is completed (whether the driving amount is in the vicinity of the correction driving amount). Repeat the operation. That is, the focus detection operation is performed during the autofocus drive based on the phase difference, and the steps # 103 to # 1 are performed.
In 05, the focus lens barrel 5 is moved while the correction drive amount is reviewed as needed.

After that, when the driving for the correction driving amount is completed, the process proceeds from step # 106 to step # 107. Since the correction driving amount has been reached, the driving is immediately switched to the low speed driving. Therefore, the deceleration operation is performed when the corrected drive amount is approached. Then, in the next step # 108, from the image of the portion corresponding to the position where the signal of the phase difference AF sensor 10 is taken out in the angle of view of the image pickup device 9, the image processing circuit 14 controls the TV and AF. Image contrast information that is an evaluation value is extracted. In the following step # 109, the evaluation of the image contrast information by the second focus evaluation circuit 15 and its history are stored. At this time, when there is a previous evaluation value, the previous evaluation value is compared, and when there is no previous evaluation value, the evaluation value is not stored.

At the next step # 110, it is determined whether or not the expected focusing range is exceeded from the autofocus result due to the phase difference. If it is, the peak position can be determined by the first contrast AF. If not, the process proceeds to step # 112 which will be described later, but if not, the process proceeds to step # 111, where it is determined whether or not the focus position (contrast peak) is passed, and if not, step # 108. Return to and repeat the same operation. On the other hand, if it is determined that the vehicle has passed, step # 112
Go to.

In the processing in steps # 108 to # 111, the assumed error range of the phase difference AF is first set to the contrast A.
This is a process of canceling the scan even if the scan is performed at F and the contrast peak is exceeded, and the scan is in the middle of the assumed error range. Therefore, when the effective evaluation value of the contrast AF cannot be obtained due to the subject dependency, the entire assumed error range of the phase difference AF is scanned, and when the effective evaluation value is obtained, the scan is stopped only in a part of the scan.

In some cases, the process proceeds to step # 112 without obtaining an effective evaluation value of the contrast AF evaluation value.
In that case, the assumed error range is scanned again as described later, and if it is still unsuccessful, the lens is moved to the expected focus position of the phase difference AF.

At step # 112, the camera control circuit 16 sends a stop command for the focus lens barrel 5 to the lens control circuit 7 on the interchangeable lens 2 side via the lens interface circuit 17. Upon receiving the command, the lens control circuit 7 controls the first actuator 6 to decelerate the focus lens barrel 5. In addition,
The actual stop is completed in step # 114 below. Then, in the next step # 113, a fine adjustment command is given to the lens control circuit 7 this time. Then, the lens control circuit 7 starts the low speed movement of the focus lens 3 in the opposite direction (because the contrast peak which is the in-focus position is exceeded) by the second actuator 4.
In the next step # 114, the decelerated focus lens barrel 5 stops.

From the deceleration of the focus lens barrel 5 in step # 112 to the stop of step # 114,
Since the focus lens 3 is started to be driven in the reverse direction, the total drive time for autofocus can be shortened. Further, with such a configuration that the control is performed, it is not necessary to suddenly stop the focus lens barrel 5, and it is possible to prevent an impact with the support member of the focus lens barrel 5. Further, it is possible to eliminate the image blur that may occur at the time of impact.

In the next step # 115, the image processing circuit 14 is started from the image of the portion corresponding to the position where the signal of the phase difference AF sensor 10 is extracted in the angle of view of the image sensor 9.
The image contrast information is extracted by. Then, in the next step # 116, the evaluation of the image contrast information by the second focus evaluation circuit 15 and the history thereof are stored.
In the following step # 117, it is determined whether or not the focus position (contrast peak) is passed, and if it is passed, the process proceeds to step # 120, and the camera control circuit 16 causes the lens control circuit 7 via the lens interface circuit 17. To the peak position stored in step # 116. As a result, the focus lens 3 is moved to the peak position obtained in step # 116. After the movement is completed, the process proceeds to step # 121 described later.

If it is determined in step # 117 that the focus position (contrast peak) has not been passed, the process proceeds to step # 118 to check whether a predetermined amount has passed from the previously obtained peak position. . This is a process for preventing the expected position of focusing by the phase difference AF from being greatly exceeded during the contrast AF, and preventing malfunction of the contrast AF. As a result, if not exceeded, the process returns to step # 115 and the same operation is repeated. On the other hand, if it exceeds, the process proceeds to step # 119 to send a command to the lens control circuit 7 to move the lens to the previously obtained peak position. As a result, the focus lens 3 is moved to the peak position obtained first. After the movement is completed, the process proceeds to step # 121.

In the next step # 121, focus display is performed on the LCD panel 11. Then, in step # 122, a normal photographing sequence is executed. After the shooting is completed, the process returns to step # 101.

As shown in the above sequence, the second actuator 4 is used for the fine adjustment operation for the final focus, and the first actuator 6 is used for the rough adjustment up to the vicinity of the focus position and the peak in the contrast AF. It is used to confirm the passage of the position.

In this configuration, the two actuators have different characteristics in order to achieve the above function.

More specifically, the second actuator 4 is biased to eliminate the influence of backlash, and the focus adjustment pitch is set finely. On the other hand, the high speed operation of the first actuator 6 is set as the highest priority, and the backlash is increased to reduce the driving load. The focus adjustment pitch is also coarse. Therefore, the amount of backlash at the time of reversal is large, and fine adjustment cannot be performed.

FIGS. 3 to 5 show the contrast A at the time of each operation described according to the flow chart of FIG.
It is a figure showing the change of the evaluation value of F and focusing operation, and the vertical axis shows the evaluation value and the horizontal axis shows the lens position. In addition, the white circles in the figure indicate the lens positions in the coarse adjustment mode, the black circles indicate the lens positions in the fine adjustment mode, and in FIGS. 3 and 4, the vertical lines extending downward indicate the sampling timing for detecting the defocus amount. Shows.

FIG. 3 shows steps # 108 to # 11 of FIG.
Corresponding to the operation part of No. 3, coarse detection of the in-focus position (contrast peak) is first performed in the coarse adjustment mode. Further, FIG. 4 corresponds to the operation part of steps # 112 to # 118 of FIG. 2, and the detailed confirmation of the focus peak position is performed in the fine adjustment mode. Further, FIG. 5 shows step # 120 of FIG.
The movement to the final in-focus position is shown corresponding to the operation part of.

The difference in sampling timing between FIG. 3 and FIG. 4 is that the moving speed of the lens is different. Of course, the sampling timing is
It can be set to a value that is more suitable for the lens to be mounted, and can be set by the focal length, aperture value, control range of drive speed, etc. of the lens.

According to the first embodiment described above, as shown in FIGS. 3 to 5, initially, the first actuator 6 is used to coarsely adjust the focus position (contrast peak) at a high speed in the coarse adjustment mode. After that, the second actuator 4 is used to accurately detect the in-focus position in the fine adjustment mode, and in-focus.

Further, since the predicted focus position is detected by the auto focus based on the phase difference and the predicted focus range is searched by the auto focus by the contrast detection, it is possible to prevent the false focus of the auto focus by the contrast detection. .

(Second Embodiment) FIG. 6 shows a second embodiment of the present invention.
FIG. 2 is a block diagram showing an electrical configuration according to the embodiment of the present invention, and shows an example applied to a lens-interchangeable digital still camera as in FIG. 1.

In the second embodiment, it is assumed that the first actuator is mounted on the interchangeable lens side and the second actuator is mounted on the digital still camera body side.

In FIG. 6, reference numeral 51 is a digital still camera body, and 52 is an interchangeable lens.

First, on the side of the interchangeable lens 52, 53 is a focus lens and 54 is a first actuator, which adjusts the focus lens 53 in the optical axis direction. 55
Is a lens control circuit, which communicates with the digital still camera body 51 and controls the first actuator 54.

Next, the digital still camera main body 51 side will be described.

Reference numeral 56 is a half mirror, and 57 is an image pickup device. Reference numeral 58 denotes a second actuator, which is the image sensor 5
7 is adjusted in the optical axis direction. Reference numeral 59 is a sensor for phase difference AF.

In the second embodiment, the interchangeable lens 5 is used.
The first actuator 54 provided on the second side is for rough adjustment,
The second actuator 58 on the digital still camera body 51 side is used for fine adjustment.

The half mirror 56 divides the photographing light beam into the image pickup element 57 and the phase difference AF sensor 59. With this configuration, the image pickup operation and the autofocus operation based on the phase difference can be performed at the same time.

Reference numeral 60 denotes an LCD panel for an electronic viewfinder, which has a built-in backlight. Reference numeral 61 denotes a finder optical system, and the LCD panel 60 can be observed through the finder optical system 61. Reference numeral 62 denotes a first focus evaluation circuit, which calculates the defocus amount from the output of the sensor 59 for phase difference AF. An image processing circuit 63 processes the output signal of the image pickup device 57, extracts the contrast information of the image, and performs white balance, γ processing, color matrix processing, and the like to form a captured image and an image for a finder.

The finder image formed by the image processing circuit 63 is sent to the LCD panel 60 and the LC
It is displayed on the D panel 60. As a result, the image for the viewfinder is provided to the photographer for observation through the viewfinder optical system 61.

A second focus evaluation circuit 64 outputs a focus evaluation value by determining the history of contrast information obtained from the image processing circuit 63. A camera control circuit 65 controls the entire digital still camera body 51. A lens interface circuit 66 exchanges signals with the lens control circuit 55 of the interchangeable lens 52. 67 is a release switch. The captured image is stored in a non-volatile memory or the like.

The operation of the digital still camera having the above configuration is similar to that of the first embodiment described above, and therefore its details are omitted.

Also in the second embodiment, as in the first embodiment, the second actuator 58 is used.
Is used for a fine adjustment operation for final focusing, and the first actuator 54 is used for rough adjustment up to the vicinity of the focusing position and for confirming passage of the peak position in autofocus by contrast detection.

According to each of the above embodiments, the following effects are obtained.

1) As a driving source for focus adjustment, a first actuator and a second actuator are provided.
Operation part of steps # 108 to # 113 (see FIG. 3)
Corresponding to the period until it is determined that the focus position (contrast peak) has been passed, the focus adjustment operation is performed by the driving by the first actuator, and after it is determined that the focus position is passed, Steps # 112 to # of FIG.
The drive by the first actuator, which corresponds to the operation portion of 118 (see FIG. 4), is stopped, and the focus adjustment operation is started by driving the second actuator in the direction opposite to the drive direction by the first actuator. Then, after that, the drive direction and the drive end of the second actuator are determined based on the autofocus result by the contrast detection, and the focus lens 3 is set to the in-focus position.

Therefore, the focus point is confirmed during high-speed coarse adjustment,
After that, since the final focusing operation is performed with the fine adjustment actuator, the search range and direction during fine adjustment can be limited,
High-speed automatic focus adjustment is possible.

2) Since the first actuator and the second actuator have the timing to operate simultaneously, the focusing operation can be further speeded up by overlapping the operations. Specifically, the focus lens 3 is moved in the opposite direction by the second actuator between the deceleration of the focus barrel 5 (by driving the first actuator) in step # 112 of FIG. 2 and the stop of step # 114. Since it is driven, the total drive time for autofocus can be shortened. Further, it is not necessary to stop the focus lens barrel 5 abruptly, it is possible to prevent an impact with the support member of the focus lens barrel 5, and it is possible to eliminate image blurring.

3) High-precision focusing accuracy can be obtained by evaluating the in-focus state by determining the contrast based on the signal from the image pickup device.

4) A first focus evaluation circuit for evaluating the in-focus state by judging the contrast based on the signal from the image pickup device, and a second focus evaluation circuit for detecting the defocus amount based on the phase difference. Since it is determined that the in-focus position has been passed based on both of these information, that is, since both the autofocus based on the phase difference and the autofocus based on the contrast detection are used, the contrast detection is performed. Unlike the case of only autofocus, it is possible to prevent false focusing.

5) As shown in FIG. 1, both the first actuator and the second actuator move the focus lens 3 directly or via the focus lens barrel 5 to integrate the moving members. Can simplify the configuration.

6) As shown in FIG. 1, the focus lens, the first actuator and the second actuator are built in the interchangeable lens, and the focusing evaluation circuit is built in the digital still camera body. Optimization can be achieved according to the type of lens. For details, it is possible to optimize the final target accuracy that is standardized for the entire system, the focus sensitivity that is different for each lens, and the consistency of the focus drive method for each lens. It is possible to eliminate an increase in cost and a decrease in focus control.

7) As shown in FIG. 6, since the focus lens is moved by the first actuator and the image pickup element is moved by the second actuator, the adjustment according to the movement is optimized. be able to. Specifically, for coarse adjustment such as when the sensitivity of the focus lens is larger than “1” like a telephoto lens, it is possible to perform the coarse adjustment on the side of the focus lens having a high focus sensitivity with respect to the imaging surface. It is possible to optimize the adjustment.

8) As shown in FIG. 6, since the focus lens and the first actuator are built in the interchangeable lens, and the second actuator and the focus evaluation circuit are built in the digital still camera main body, It is not necessary to provide two drive sources for each interchangeable lens, the merit of the interchangeable lens system can be utilized, and the cost of the total system can be reduced.

[0080]

As described above, according to the first aspect of the invention, the focus position is confirmed during high-speed coarse adjustment, and then the final focus operation is performed by the second actuator for fine adjustment. , By limiting the search range and direction during fine adjustment,
It is possible to provide an automatic focus adjustment device capable of performing high-speed automatic focus adjustment.

According to the second aspect of the present invention, the automatic focusing can be performed at a higher speed by partially overlapping the driving of the first focused member and the second focused member. It is possible to provide an automatic focusing device that can be used.

According to the third aspect of the present invention, it is possible to provide an automatic focus adjusting device in which the first focused member and the second focused member can be integrated to simplify the structure. It is a thing.

Further, according to the invention described in claim 4, it is possible to provide an automatic focus adjusting device which can be optimized according to the type of the interchangeable lens.

Further, according to the invention described in claim 5, it is possible to provide an automatic focus adjusting device capable of obtaining a highly accurate focusing accuracy by contrast detection.

According to the sixth aspect of the present invention, by using both the automatic focus adjustment based on the phase difference and the automatic focus adjustment based on the contrast detection, false focusing due to the automatic focus adjustment based on the contrast detection can be prevented. It is possible to provide an automatic focusing device capable of performing the above.

According to the invention described in claim 7, it is possible to provide a camera system capable of optimizing the adjustment according to the movement content.

Further, according to the invention described in claim 8, it is possible to provide a camera system capable of reducing the cost of the total camera system.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of a digital still camera according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing an operation of the digital still camera according to the first embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between an evaluation value and a lens position corresponding to the operation part of steps # 108 to # 113 of FIG.

FIG. 4 is a diagram showing a relationship between an evaluation value and a lens position corresponding to the operation part of steps # 112 to # 118 of FIG.

5 is a diagram showing a relationship between an evaluation value and a lens position, which corresponds to the operation part of step # 120 in FIG.

FIG. 6 is a block diagram showing an electrical configuration of a digital still camera according to a second embodiment of the present invention.

[Explanation of symbols]

1,51 Digital still camera body 2,52 interchangeable lens 3,53 Focus lens 4,54 Second actuator 5 Focus barrel 6,58 1st actuator 7,55 lens control circuit 9,57 Image sensor 10,59 Phase difference AF sensor 11,60 LCD panel 12,61 Finder optical system 13, 62 First Focus Evaluation Circuit 14,63 Image processing circuit 15, 64 Second focus evaluation circuit 16,65 Camera control circuit

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Claims (8)

[Claims] 1. A first for coarse adjustment which is a drive source for focus adjustment.
In the automatic focus adjusting device having the actuator, the second actuator for fine adjustment that is a drive source for focus adjustment, and the focus state determination means for determining the focus state, During the period until it is determined that the focusing member has passed the in-focus position, the in-focus member is moved in the direction of the in-focus position by the drive of the first actuator, and the in-focus position is passed. Is determined, the drive by the first actuator is stopped, and the focused member is started to move by the drive by the second actuator in the direction opposite to the drive direction by the first actuator, and thereafter, Determines the drive direction of the second actuator and the end of the drive based on the output of the focusing state determination means. Knot device. 2. The focusing member comprises a first focusing member and a second focusing member, and the first focusing member is driven by the first actuator for coarse adjustment. The second in-focus member is moved by the driving of the second actuator for fine adjustment, and has a timing at which the first actuator and the second actuator are simultaneously driven. The automatic focusing device according to claim 1. 3. The first focusing member is a focusing barrel having a focusing lens therein, and the second focusing member is movable in the focusing barrel. The automatic focusing device according to claim 2, which is a focusing lens. 4. The automatic focus adjustment according to claim 2, wherein the first focused member is a focusing lens, and the second focused member is an image recording medium. apparatus. 5. The in-focus state determination means evaluates the in-focus state by determining the contrast based on a signal from an image capturing means that captures light from a subject and converts it into an electrical signal. The automatic focus adjustment device according to claim 1. 6. A first focus that evaluates the focus state by determining the contrast based on a signal from an image capturing unit that captures light from a subject and converts it into an electrical signal. And a second focusing state determining unit that calculates a defocus amount based on the phase difference and evaluates the focusing state. The first focusing state determining unit and the second focusing state 3. The method according to claim 1, wherein it is determined that the in-focus member has passed a focus position based on both outputs of the determination means.
The automatic focus adjustment device according to any one of 1 to 5. 7. A camera system comprising an interchangeable lens and a camera body, comprising the automatic focus adjustment device according to claim 2 or 3, wherein the first focusing member and the second focusing member are provided. A focusing system, the first actuator, and the second actuator are built in the interchangeable lens, and the focusing state determination means is built in the camera body side. 8. A camera system comprising an interchangeable lens and a camera body, comprising the automatic focus adjustment device according to claim 2 or 4, wherein the first focused member and the first actuator are The second focusing member built in the interchangeable lens,
The camera system, wherein the second actuator and the focusing state determination means are built in the camera body side.