JP5610929B2 - Imaging device - Google Patents

Description

  The present invention relates to an imaging apparatus such as a digital camera or a digital video camera, and more particularly to an imaging apparatus capable of both capturing a visible light image and capturing an infrared light image.

  In autofocus (AF) control of a video camera or the like, an AF evaluation value signal indicating the sharpness (contrast state) of a video signal generated using an image sensor is generated, and the focus lens that maximizes the AF evaluation value signal is generated. The TV-AF method for searching for a position is the mainstream. Although this TV-AF method enables high-precision focus control, it needs to search for a focus lens position where the AF evaluation value signal is maximum, and thus has a weak point that it takes a long time to focus. Accordingly, various hybrid AF methods combining the TV-AF method and other AF methods have been proposed.

  As an AF method combined with the TV-AF method, a distance measuring sensor is provided independently of the photographing lens, and a focus lens in-focus position is calculated from the distance to the subject detected by the distance measuring sensor, and the focus lens is provided there. There is an external ranging method (external measurement phase difference detection method) that moves the distance (see Patent Document 1). In the external measurement phase difference detection method, a light beam received from an object is divided into two, and the two divided light beams are received by a set of light receiving element arrays (line sensors). Then, the amount of deviation of the image formed on the set of line sensors, that is, the phase difference is detected, the subject distance is obtained from the phase difference using the triangulation method, and the subject is focused on the subject distance. Move the focus lens to.

  Another AF method is an internal measurement phase difference detection method. In the internal measurement phase difference detection method, the light beam that has passed through the exit pupil of the photographing lens is divided into two, and the two divided light beams are received by a set of focus detection sensors. Then, the amount of deviation in the focus direction of the photographing lens is directly obtained by detecting the amount of deviation of the image output according to the amount of received light, that is, the amount of relative positional deviation in the light beam splitting direction (see Patent Document 2). . Further, an AF method has been proposed in which a special pixel for phase difference detection is provided in the image pickup device itself of the camera so that the internal measurement phase difference can be detected without dividing the light beam (see Patent Document 3).

  In the AF method based on phase difference detection as described above, information about the focus lens focus position and the amount of focus shift can be obtained directly, so that high-speed focus control is possible. Therefore, in the hybrid AF method, the focus lens is moved to the vicinity of the in-focus point by the phase difference detection method, and then the TV-AF method is moved to adjust the focus position, thereby realizing high-speed and high-precision AF control. Yes.

JP 2005-234325 A JP-A-5-64056 JP 2008-134389 A

  Generally, a digital camera or a digital video camera includes a filter that removes an infrared light component from a light component incident on an image sensor from an imaging optical system. This is because the image sensor is also sensitive to infrared light components, so that the color reproducibility of the captured image is reduced due to the mixture of infrared light components, and the resolution is prevented from being lowered due to aberrations. Because.

  On the other hand, in order to enable photographing in a dark place where the amount of visible light is insufficient, an imaging apparatus provided with a filter switching means that puts and removes an infrared light removal filter on the optical path of the imaging optical system has been proposed. Yes. This is because, in normal shooting with visible light (hereinafter referred to as “visible light shooting mode”), an infrared light removal filter is placed on the optical path for shooting, while in a dark place where there is little visible light, the infrared light removal filter is used for the optical path. Moving outside, it is also possible to shoot with infrared light (hereinafter referred to as infrared light shooting mode).

  By the way, when the infrared light removal filter is taken in and out of the optical path in this way, the focus characteristic of the focus lens changes as a result of the change in the optical characteristics of the imaging optical system depending on the presence or absence of the infrared light removal filter. FIG. 6 shows an amount of change in focus position of the focus lens and zoom when the infrared light removal filter is moved from the optical path to the outside of the optical path in an imaging lens having a zoom lens that changes the magnification of the imaging optical system. It is the figure which showed the relationship of a lens position. The curve indicated by L1 in FIG. 6 is the amount of change in the focus position in an environment where only visible light is present. The left end of the figure indicates the wide-angle end position of the zoom lens, and the right end indicates the telephoto end position. . On the other hand, the curve indicated by L2 in FIG. 6 is the amount of change of the in-focus position under the environment of only infrared light, and is greatly different from the curve L1. In an environment where visible light and infrared light components are mixed, the amount of change in the focus position is an intermediate characteristic between L1 and L2. The amount of change in the in-focus position varies depending on the component ratio of visible light and infrared light as described above because of the chromatic aberration characteristic of the lens of the imaging optical system.

  Here, when the above-described hybrid AF is applied to a camera in which the above-described infrared light removal filter can be taken in and out of the optical path, the following two problems occur.

  First, due to the change in the focus position of the focus lens due to the presence or absence of the infrared light removal filter, the focus position of the focus lens determined by the phase difference detection AF is shifted from the actual focus position. There is a problem that the phase difference detection AF operation is out of focus. The reason is as follows.

  When an infrared light removal filter is arranged on the image sensor side of the light beam split point in the external measurement phase difference detection method or the internal measurement phase difference detection method, the infrared light removal filter is outside the optical path of the phase difference detection sensor. is there. For this reason, even if the infrared light removal filter moves out of the optical path, the focus position of the focus lens obtained by the phase difference detection AF does not change. On the other hand, in the imaging optical system of the imaging device, the in-focus position changes due to the movement of the infrared light removal filter. For this reason, when the phase difference detection AF operation is performed in the hybrid AF control, there arises a problem that the focus is blurred.

  Second, when there is no infrared light removal filter, the subject image becomes unclear, the focusing accuracy of the phase difference detection method is lowered, and there is a problem that the focus is blurred by the phase difference detection AF operation. The reason is as follows.

  As described above, when there is no infrared light removal filter, the in-focus position is shifted depending on the chromatic aberration characteristics of the lens. In general, a subject image contains light components of various frequencies including infrared light components, and the focus position differs for each component, so the subject image is not clearly focused and is not clear. End up. As described above, in the phase difference detection method, the amount of deviation between the two images is detected. Therefore, an accurate amount of deviation cannot be detected in a blurred subject image, and the focusing accuracy is reduced. Such a problem is caused by an internal measurement phase difference detection method in which an infrared light removal filter is arranged on the subject side from the beam split point or an internal measurement phase difference detection in which an image sensor is provided with a pixel for phase difference detection. This occurs in a configuration in which an infrared light removal filter is disposed on an optical path of a phase difference detection method, such as a method.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to suppress a reduction in the accuracy of AF operation in an imaging apparatus in which an infrared light removal filter can be taken in and out of the optical path and has a hybrid AF function. It is to be.

Imaging device according to the present invention includes a light beam from an object incident through an imaging optical system including a focus lens and an image pickup device which photoelectrically converts and generates an output signal, the light flux incident on the image sensor Based on an infrared light removal filter that removes infrared light components, a drive unit that puts the infrared light removal filter into and out of the optical path of the imaging optical system, and a contrast state of an output signal obtained from the imaging device A first detection unit that detects a focusing state of the imaging optical system; and a second detection unit that divides a light beam from a subject into two light beams and detects a shift amount of two images obtained from the two light beams. A detector that is disposed on an optical path of the imaging optical system and divides a light beam from a subject into a first light beam toward the image sensor and a second light beam toward the second detector; and First detection means Focus adjustment control means for performing focus adjustment of the imaging optical system using at least one of focus information based on the in-focus state obtained and focus information based on an image shift amount obtained by the second detection means. The infrared light removal filter is disposed in an optical path between the dividing unit and the imaging device, and the focus adjustment control unit is configured such that the infrared light removal filter is positioned outside the optical path of the imaging optical system. In this case, the use of the focus information based on the image shift amount obtained by the second detection means is limited.

  According to the present invention, an infrared light removal filter can be taken in and out of the optical path, and in an imaging apparatus having a hybrid AF function, it is possible to suppress a decrease in AF operation accuracy.

1 is a block diagram showing a configuration of an imaging apparatus according to a first embodiment of the present invention. 6 is a flowchart illustrating AF control switching processing according to the first embodiment of the present invention. The block diagram which shows the structure of the imaging device of the 2nd Embodiment of this invention. The block diagram which shows the structure of the imaging device of the 3rd Embodiment of this invention. The block diagram which shows the structure of the imaging device of the 4th Embodiment of this invention. The figure which shows the example of the focus position variation | change_quantity of a focus lens when moving an infrared-light removal filter out of an optical path.

(First embodiment)
FIG. 1 is a block diagram showing a configuration of a video camera which is a first embodiment of the imaging apparatus of the present invention.

  In FIG. 1, 101 is a fixed first group lens, 102 is a variable power lens (hereinafter referred to as a zoom lens) that performs zooming, 103 is a stop, and 104 is a fixed second group lens. Reference numeral 105 denotes a focus lens (hereinafter referred to as a “focus lens”) that has both a function of correcting the movement of the focal plane accompanying zooming and a function of focusing (a function of adjusting the imaging position). These constitute an imaging optical system.

  Reference numeral 118 denotes an infrared light removing filter that removes an infrared light component from light from a subject, and can be moved out of the optical path of the imaging optical system by a driving mechanism (not shown). Reference numeral 106 denotes an image sensor such as a CCD sensor or a CMOS sensor that photoelectrically converts a subject image, and 107 denotes an image sensor control circuit that controls the operation of the image sensor 106 and samples the output of the image sensor 106. A camera signal processing circuit 108 performs various image processing on the output signal from the image sensor control circuit 107 to generate a video signal.

  Reference numeral 109 denotes a monitor device, which is a display device for displaying an output signal of the camera signal processing circuit 108 and used for a photographer to monitor an image, and for displaying a camera status display and various warning displays to the photographer. Is done. A recording device 113 records the video signal generated by the camera signal processing circuit 108 on a recording medium such as a magnetic tape, an optical disk, a magnetic disk, or a semiconductor memory.

  A zoom drive source 110 is a motor for moving the zoom lens 102, and a focusing drive source 111 is a motor for moving the focus lens 105. A stepping motor, a direct-acting voice coil motor, or the like is used. It is done. Reference numeral 119 denotes a filter drive source which is a motor for moving the infrared light removal filter 118 in and out of the optical path of the imaging optical system.

  Each of the above driving sources is controlled by a driving command from a camera microcomputer 114 described later. The positions of the lenses and filters driven by the respective driving sources are detected by position detection means (not shown) and used for various controls by the camera microcomputer 114. As the position detecting means, a sensor for detecting the position may be provided. When a stepping motor is used as a driving source, the camera microcomputer 114 counts the number of driving pulses for driving the stepping motor. Thus, the position may be detected.

  The camera microcomputer 114 is a microcomputer that controls the operation of the entire video camera, and various controls according to the present embodiment are also executed by this microcomputer.

  Reference numeral 112 denotes a focus signal processing circuit (first detection means) that extracts a high-frequency component from the video signal generated by the camera signal processing circuit 108 and generates a focus signal. This focus signal (focus information) represents the sharpness (contrast state) of the captured subject image, but the sharpness changes depending on the focus state of the subject image. Signal. When the video camera is controlled in an autofocus state, a known TV-AF control process is executed by the camera microcomputer 114 using this focus signal. In other words, using the fact that the focus signal has the property of being maximized when the subject image is in focus, the focus lens 105 is moved to detect the change of the focus signal, and the focus signal is at the position where the focus signal is maximized. The focus lens 105 is moved. Thus, the subject image can be focused with high accuracy by the TV-AF method.

  Reference numeral 116 denotes an external distance measurement unit (second detection means) that outputs distance information to the subject by an external measurement phase difference detection method. In the external measurement phase difference detection method, a light beam received from an object is divided into two, and the two divided light beams are received by a set of light receiving element arrays (line sensors). Then, the amount of deviation of the image formed on the set of line sensors, that is, the phase difference is detected, the subject distance is obtained from the phase difference using the triangulation method, and the subject is focused on the subject distance. Move the focus lens to.

  Ranging information from the external ranging unit 116 is taken into the camera microcomputer 114 and converted into a focus lens position. By moving the focus lens 105 to the focus lens position obtained here, the focus lens can be moved to the vicinity of the focus position at high speed by the phase difference detection AF method.

  Reference numeral 117 denotes an operation mode switching switch which is operated when the photographer switches between the visible light photographing mode and the infrared light photographing mode. When the infrared light shooting mode is selected, the camera microcomputer 114 controls the filter drive source 119, the infrared light removal filter 118 is moved out of the optical path of the image pickup optical system, and the image pickup apparatus is moved to the infrared light. Shooting conditions suitable for optical shooting are set. On the other hand, when the visible light imaging mode is selected, the infrared light removal filter 118 is moved on the optical path, and the imaging device is set to imaging conditions suitable for visible light imaging.

  In the above description, the infrared light removal filter 118 is moved by the filter drive source 119 in accordance with the switching of the operation mode switch, but the filter moving means and the operation mode switching means are used as a common member as follows. It is good also as a structure. That is, instead of the filter drive source 119, a lever or the like for manually moving the infrared light removal filter 118 in and out of the optical path is provided. When the photographer operates the lever to move the filter out of the optical path, the camera microcomputer 114 detects the movement of the filter by a filter position detection unit (not shown), and switches the operation mode to the infrared light imaging mode. Conversely, when the filter is moved on the optical path by lever operation, the operation mode is switched to the visible light photographing mode. In this way, it is not necessary to provide a motor as the filter driving means, and the size and cost of the imaging apparatus can be reduced.

  In the present embodiment, the infrared light removal filter is outside the optical path of the external distance measuring unit 116 which is a phase difference detection sensor. For this reason, as described above, due to the change in the focus position of the focus lens due to the presence or absence of the infrared light removal filter, the focus lens obtained by phase difference detection AF is between the focus position and the actual focus position. Deviation occurs.

  Next, switching of the focus adjustment control process when the operation mode is the visible light photographing mode and the infrared light photographing mode, which is a feature of the present embodiment, will be described with reference to the flowchart of FIG.

  In FIG. 2, in S <b> 101, it is determined based on the information of the operation mode changeover switch 117 whether the video camera is in the visible light photographing mode or the infrared light photographing mode. If it is determined that the mode is the visible light photographing mode, there is no deviation between the focus position of the focus lens and the actual focus position in the phase difference detection AF as described above. AF control is executed and the process returns to S101. That is, after the focus lens is moved to the vicinity of the in-focus point by the phase difference detection method, the focus adjustment control is performed so as to shift to the TV-AF method and adjust the focus position.

  On the other hand, if it is determined in S101 that the video camera is in the infrared light shooting mode, the focus position of the focus lens in phase difference detection AF and the actual focus position will deviate. In addition, the operation of phase difference detection AF is limited by the processing after S103.

  First, in S103, the current focus lens position Pf is detected by the position detecting means described above. In step S104, the focus position Pf0 of the focus lens in the phase difference detection AF is calculated. However, as described above, since the focus position Pf0 here is deviated from the actual focus position, control for moving the focus lens to Pf0 is not performed, and the process proceeds to S105.

  In S105, the difference between the current focus lens position Pf and the focus lens focus position Pf0 in the phase difference detection AF is calculated, and the process proceeds to S106. In S106, it is determined whether or not the absolute value of the difference is larger than a threshold value Th. This threshold value Th is the amount of deviation between the in-focus position and the actual in-focus position in the phase difference detection AF based on the presence or absence of the infrared light removal filter, and the alignment of the phase difference detection AF due to the subject image becoming unclear. Based on the focal position error amount, a value sufficiently larger than these is set. The focus position Pf0 of the focus lens in the phase difference detection AF has an uncertainty of about the threshold value Th with respect to the actual focus position, but if the above difference is larger than the threshold value Th. It can be said that it is possible to determine whether the actual in-focus position is on the infinity side or the near side from the current focus lens position Pf. Note that, as shown in FIG. 6, the change in the focus lens focus position depending on the presence or absence of the infrared light removal filter changes according to the zoom position, so the threshold value may be changed according to the zoom position. Good.

  If it is determined in S106 that the difference is not greater than the threshold value, it is not possible to determine in which direction the actual focus position is relative to the current focus lens position Pf. The focus adjustment control by the AF method is executed, and the process returns to S101. On the other hand, if it is determined that the difference is greater than the threshold value, it is possible to determine whether the actual focus position is in the infinity side or the near side with respect to the current focus lens position Pf. Since there is, it progresses to S108.

  In S108, it is determined whether or not the focus position Pf0 of the focus lens in the phase difference detection AF is on the infinity side with respect to the current focus lens position Pf. If it is determined that the focus lens is on the infinity side, the process proceeds to S109, and the focus lens for searching for a focus position (focus lens position where the AF evaluation signal is maximized) in the focus adjustment control by the TV-AF method is set to the optical axis. The scanning position (moving direction) for scanning in the direction is set to the infinity side. Then, the process proceeds to S107, the focus adjustment control by the TV-AF method is executed, and the process returns to S101. On the other hand, if it is determined in S108 that Pf0 is closer to Pf, the process proceeds to S110 and the TV-AF focus position search direction is set to the closer side. Then, the process proceeds to S107, the focus adjustment control by the TV-AF method is executed, and the process returns to S101.

  As described above, in the infrared light shooting mode in which the accuracy of the focus position in the phase difference detection AF is low, the information of the phase difference detection AF is used only for determining the search direction of the focus position in the TV-AF method. The focus lens is not moved in the phase difference detection AF. Therefore, the focus is not blurred due to the shift of the focus position of the phase difference detection AF.

  In the above description, in the infrared light shooting mode, the TV-AF method focus position search direction is set based on the phase difference detection AF focus position information, and the TV-AF method focus adjustment is performed. Control is in progress. However, focus adjustment control may be performed only by the TV-AF method without using the information of the phase difference detection AF. However, in this case, the time required for searching for the in-focus position in the TV-AF method becomes long.

  As described above, according to the present embodiment, high-speed and high-precision AF control is performed by the hybrid AF method in the visible light photographing mode, while the focus lens movement is performed in the phase difference detection AF in the infrared light photographing mode. Focus adjustment control is performed by the TV-AF method without performing the above. Therefore, there is no out-of-focus due to the shift of the focus position in the phase difference detection AF, and the focused state of the image can be kept good. In addition, in the infrared light shooting mode, since the search direction of the focus position in the TV-AF method is determined using the information on the focus position in the phase difference detection AF, the focus in the TV-AF method is determined. The time required for the position search can be shortened.

(Second Embodiment)
FIG. 3 is a block diagram showing the configuration of the video camera according to the second embodiment of the present invention. In the first embodiment, the case of using the external measurement phase difference detection method has been described. However, in this embodiment, the internal measurement phase difference detection method is used. In the internal phase difference detection method, the light beam that has passed through the exit pupil of the imaging optical system is divided into a first light beam and a second light beam, and the two divided light beams are received by a set of focus detection sensors. Then, the amount of deviation in the focus direction of the imaging optical system is directly obtained by detecting the amount of deviation of the image output according to the amount of received light, that is, the amount of relative positional deviation in the split direction of the light beam. In addition, about the component which is common in said 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In this embodiment, the imaging optical system includes, in order from the subject side, a fixed first lens group 101, a variable power lens (zoom lens) 102, a focus lens (focus lens) 105, a diaphragm 103, and a fixed second lens group. And a lens 104. The infrared light removal filter 118 is disposed between the second group lens 104 and the image sensor 106.

  A half prism 621 is disposed between the focus lens 105 and the diaphragm 103. The half prism 621 divides the light beam from the focus lens 105 toward the stop 103 into a light beam component toward the image sensor 106 and a light beam component toward an AF sensor 624 described later. Since the diaphragm 103 is always operating during moving image shooting, the incident total luminous flux is divided by the half prism 621 disposed on the subject side of the diaphragm 103.

  Reference numeral 622 denotes a sub mirror that reflects the light beam component divided by the half prism 621, and 623 denotes an imaging lens that forms an image on the AF sensor 624 on the light beam reflected by the sub mirror 622. The AF sensor 624 has a pair of light receiving element arrays (line sensors) for phase difference detection AF. Reference numeral 625 denotes an AF circuit that calculates a phase difference between two image signals formed on a pair of line sensors of the AF sensor 624.

  Based on the phase difference information from the AF circuit 625, the camera microcomputer 114 calculates the focus shift amount and shift direction. In the video camera configured as described above, in the hybrid AF control described in the first embodiment, the focus shift based on the phase difference information from the AF circuit 625 instead of the distance measurement information from the external distance measurement unit 116. A similar AF process is performed using the information on the amount and the shift direction.

  In the present embodiment, since the infrared light removal filter is disposed closer to the image sensor 106 than the half prism 621, it is outside the optical path of the AF sensor 624 that is a phase difference detection sensor. Therefore, as in the first embodiment, when the video camera is in the infrared light shooting mode, a deviation occurs between the focus position of the focus lens obtained by the phase difference detection AF and the actual focus position. .

  The focus adjustment control process switching between the case where the operation mode is the visible light photographing mode and the case where the operation mode is the infrared light photographing mode, which is a feature of the present embodiment, is the same as the flowchart of FIG. 2 described in the first embodiment. Since there is, explanation is omitted. As in the first embodiment, focus adjustment control is performed by the TV-AF method without moving the focus lens in the phase difference detection AF in the infrared light photographing mode. Therefore, there is no out-of-focus due to the shift of the focus position in the phase difference detection AF, and the focused state of the image can be kept good.

(Third embodiment)
FIG. 4 is a block diagram showing a configuration of a video camera according to the third embodiment of the present invention. In this embodiment, the internal phase difference detection method is used as in the second embodiment. In addition, about the component which is common in 1st and 2nd embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In the present embodiment, the infrared light removal filter 118 is disposed between the focus lens 105 and the half prism 621. Also in the present embodiment, AF processing similar to that in the second embodiment can be performed based on the information on the focus shift amount and shift direction based on the phase difference information from the AF circuit 625.

  In the present embodiment, since the infrared light removal filter is disposed on the subject side of the half prism 621, it is on the optical path of the AF sensor 624 that is a phase difference detection sensor. For this reason, unlike the first and second embodiments, there is no deviation between the focus position of the focus lens obtained by the phase difference detection AF and the actual focus position. However, as described above, when there is no infrared light removal filter, the focus position is shifted due to the chromatic aberration characteristics of the lens, so that the subject image is not clearly focused but becomes unclear. As a result, an accurate shift amount cannot be detected by the phase difference detection method, and the focusing accuracy is lowered.

  The focus adjustment control process switching between the case where the operation mode is the visible light photographing mode and the case where the operation mode is the infrared light photographing mode, which is a feature of the present embodiment, is the same as the flowchart of FIG. 2 described in the first embodiment. Since there is, explanation is omitted. In the present embodiment, as described above, since there is no deviation between the focus position in the phase difference detection AF and the actual focus position due to the presence or absence of the infrared light removal filter, the threshold value in S106 in FIG. Th may be set based only on the error amount of the focus position of the phase difference detection AF due to the subject image becoming unclear.

  Also in the present embodiment, focus adjustment control is performed by the TV-AF method without moving the focus lens in the phase difference detection AF in the state of the infrared light photographing mode. For this reason, the subject image becomes unclear in phase difference detection AF, and there is no out-of-focus due to a decrease in focusing accuracy, and the focused state of the image can be kept good.

(Fourth embodiment)
FIG. 5 is a block diagram showing a configuration of a video camera according to the fourth embodiment of the present invention. In this embodiment, the internal measurement phase difference detection method is used. However, by providing the image sensor itself with a pixel for detecting the phase difference, the internal measurement phase difference detection is performed without dividing the light beam by the half prism 621. Yes. In addition, about the component which is common in 1st and 2nd embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The imaging optical system of the present embodiment is the same as that of the first embodiment, but pixels for phase difference detection are provided on the image sensor 106. The output of the image sensor 106 is processed by the image sensor control circuit 107 and the camera signal processing circuit 108. The AF circuit 625 reads a pixel signal for phase difference detection from the output of the camera signal processing circuit 108 and calculates the phase difference. Using the information on the focus shift amount and shift direction based on the phase difference information from the AF circuit 625, AF processing similar to that in the second and third embodiments can be performed.

  In this embodiment, since the image sensor also serves as a phase difference detection sensor, the infrared light removal filter is on the optical path of the phase difference detection sensor. Therefore, as in the third embodiment, there is no deviation between the focus position of the focus lens obtained by the phase difference detection AF and the actual focus position. However, as in the third embodiment, when there is no infrared light removal filter, the subject image becomes unclear and the focusing accuracy of the phase difference detection method is lowered.

  The focus adjustment control process switching between the case where the operation mode is the visible light photographing mode and the case where the operation mode is the infrared light photographing mode, which is a feature of the present embodiment, is the same as the flowchart of FIG. 2 described in the first embodiment. Since there is, explanation is omitted. In this embodiment as well, as in the third embodiment, there is no deviation between the focus position in the phase difference detection AF and the actual focus position due to the presence / absence of the infrared light removal filter. The threshold value Th may be set based only on the error amount of the in-focus position of the phase difference detection AF due to the subject image becoming unclear.

  Also in the present embodiment, focus adjustment control is performed by the TV-AF method without moving the focus lens in the phase difference detection AF in the state of the infrared light photographing mode. For this reason, the subject image becomes unclear in phase difference detection AF, and there is no out-of-focus due to a decrease in focusing accuracy, and the focused state of the image can be kept good.

  Although the present invention has been described in detail based on preferred embodiments thereof, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are also included in the present invention. included. Moreover, you may combine suitably a part of above-mentioned embodiment.

Claims (4)

An image sensor for generating an output signal by photoelectrically converting a light beam from a subject incident through the imaging optical system including a focus lens,
And an infrared light removal filter that removes infrared light component contained in the light flux incident on the imaging element,
Drive means for moving the infrared light removal filter in and out of the optical path of the imaging optical system;
First detection means for detecting a focusing state of the imaging optical system based on a contrast state of an output signal obtained from the imaging element;
A second detection unit that divides a light flux from the subject into two light fluxes and detects a shift amount of two images obtained from the two light fluxes;
A splitting unit disposed on the optical path of the imaging optical system and splitting a light beam from a subject into a first light beam traveling toward the image sensor and a second light beam traveling toward the second detection unit;
Focus adjustment of the imaging optical system is performed using at least one of focus information based on the in-focus state obtained by the first detection unit and focus information based on an image shift amount obtained by the second detection unit. A focus adjustment control means,
The infrared light removal filter is disposed in an optical path between the dividing unit and the imaging device,
The focus adjustment control unit limits use of focus information based on an image shift amount obtained by the second detection unit when the infrared light removal filter is located outside the optical path of the imaging optical system. An imaging apparatus characterized by that.   The imaging apparatus according to claim 1, wherein the second detection unit is arranged outside an optical path of the imaging optical system. The focus adjustment control unit is limited to not use focus information based on an image shift amount obtained by the second detection unit when the infrared light removal filter is located outside the optical path of the imaging optical system. The imaging apparatus according to claim 1 , wherein focus adjustment is performed using information based on a focus state obtained by the first detection unit. An image sensor that photoelectrically converts a light beam from a subject incident through an imaging optical system including a focus lens to generate an output signal;
An infrared light removal filter that removes an infrared light component contained in a light beam incident on the image sensor;
Drive means for moving the infrared light removal filter in and out of the optical path of the imaging optical system;
First detection means for detecting a focusing state of the imaging optical system based on a contrast state of an output signal obtained from the imaging element;
A second detection unit that divides a light flux from the subject into two light fluxes and detects a shift amount of two images obtained from the two light fluxes;
Focus adjustment of the imaging optical system is performed using at least one of focus information based on the in-focus state obtained by the first detection unit and focus information based on an image shift amount obtained by the second detection unit. A focus adjustment control means,
The focus adjustment control unit includes the focus lens among focus information based on an image shift amount obtained by the second detection unit when the infrared light removal filter is located outside the optical path of the imaging optical system. And controlling the direction of movement of the focus lens in the optical axis direction using the detection result of the first detection means based on the information on the movement direction. imaging device according to claim.

Images