JP6799411B2 - Focus detection device and method, and imaging device - Google Patents

Description

The present invention relates to a focus detection device and method, and an image pickup device, and more particularly to a focus detection technique for photographing a subject moving at a constant speed.

In recent years, noise reduction technology for digital cameras has improved, and image quality has dramatically improved, especially in high-sensitivity shooting. As a result, astronomical photography, which was difficult in the past, has become easier, and digital cameras have come to be equipped with a function that allows anyone to easily photograph the starry sky.

However, when shooting a starry sky, one of the most important camera functions is a means of focusing on a star. Since a star is a very dark subject, it is difficult to focus on the star with the normal AF function, and the influence of the diurnal motion of the star cannot be ignored, especially when shooting at high magnification. It was difficult to focus.

Japanese Unexamined Patent Publication No. 2014-6477

Reference 1 discloses a technique for facilitating focusing by changing the size and position of the AF frame according to the lens magnification of the image pickup apparatus. However, when shooting an astronomical object, it is common to fix it on a tripod or the like, and in addition to the image magnification, there is image plane movement due to the diurnal motion of the star as the subject. Therefore, even if the AF frame is expanded according to the image magnification, stars may appear from the AF frame during AF, and AF may not be completed normally.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the focus detection accuracy when shooting a subject moving at a constant speed such as an astronomical object.

In order to achieve the above object, the focus detection device of the present invention acquires pixel information including the number of pixels of an imaging element and the size of an imaging region that receive light incident on the photographing optical system and output an image signal. Pixel information acquisition means for acquiring image angle information acquisition means for acquiring information on the image angle of the photographing optical system, and range setting means for setting a focus detection range which is a region used for focus detection on the imaging surface of the imaging element. , Information on the focus detection means for detecting the focus evaluation value based on the image signal obtained from the focus detection range and detecting the focusing position of the photographing optical system based on the focus evaluation value, and the angle of view. A calculation means for obtaining the distance that the image of the subject moving during the detection time moves on the imaging surface based on the detection time required for detecting the focus evaluation value and the pixel information, and the focus detection. It has a frame setting means for setting a frame representing a range narrowed by the distance to be displayed on the display means for displaying the image signal.

According to the present invention, it is possible to improve the focus detection accuracy when shooting a subject that moves at a constant speed such as an astronomical object.

The block diagram which shows the structure of the image pickup apparatus in embodiment of this invention. The figure explaining the movement amount of the subject image on the image pickup surface of an image pickup apparatus. The figure explaining the relationship between the imaging range, the AF frame, the focus detection range, and the division area in the embodiment. The figure explaining the relationship between the image pickup range, the subject image, the AF frame, the focus detection range, and the division area at the time of wide-angle to medium telephoto in the embodiment. The figure for demonstrating the relationship between the focal point detection range at the time of telephoto, and the AF frame in an embodiment. The figure explaining an example of the setting method of the focus detection area at the time of telephoto in an embodiment. The figure explaining an example of the setting method of the focus detection area at the time of telephoto in an embodiment. The figure for demonstrating the relationship between the focal point detection range at the time of super-telephoto, and the AF frame in an embodiment. The flowchart explaining the flow of AF processing in Embodiment. The flowchart explaining the flow of the focus detection process in Embodiment. The flowchart explaining the flow of the setting process of the focal point detection area in an embodiment.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a schematic configuration of an image pickup apparatus according to an embodiment of the present invention. As shown in FIG. 1, the image pickup apparatus of this embodiment is mainly composed of a camera body 100 and an interchangeable lens type lens unit 150 (shooting optical system). The lens unit 150 has a configuration in which it can be attached to and detached from the camera body 100 via a connector 96 and a connector 97 having electrical contacts.

The lens unit 150 includes a variable magnification lens (hereinafter, zoom lens) 10, a focus lens (hereinafter, focus lens) 12, an aperture shutter unit 13, and a connector 96.

The light incident through the lens unit 150 is imaged on the image sensor 14 of the camera body 100 as an optical image, and the image sensor 14 receives the imaged light and outputs an analog image signal. The gain amplifier 120 that sets the sensitivity of the camera amplifies the analog signal output from the image sensor 14 and outputs it to the A / D converter 16. The A / D converter 16 converts the amplified analog signal into a digital signal. Further, the timing generation circuit 18 supplies a clock signal and a control signal to the image pickup element 14, the A / D converter 16, and the D / A converter 26, respectively, and is controlled by the memory control circuit 22 and the system control circuit 50.

The image processing circuit 20 performs predetermined pixel interpolation processing and color conversion processing on the data from the A / D converter 16 or the data from the memory control circuit 22. Further, the image processing circuit 20 performs a predetermined arithmetic process using the image data output from the A / D converter 16. Then, based on the obtained calculation result, the system control circuit 50 performs TTL (through-the-lens) automatic exposure (AE) processing, calculates an appropriate exposure value, and controls the exposure control circuit 40. .. Further, the system control circuit 50 performs TTL (through-the-lens) AF (autofocus) processing based on the focus evaluation value indicating the in-focus state in the focus detection region on the imaging surface, and the focus control circuit 42 The focus lens 12 is driven via the lens 12 to adjust the focus. Further, in the image processing circuit 20, a predetermined arithmetic process is performed using the image data output from the A / D converter 16, and a TTL-type auto white balance (AWB) process is also performed based on the obtained arithmetic result. Is going.

The memory control circuit 22 controls the A / D converter 16, the timing generation circuit 18, the image processing circuit 20, the image display memory 24, the D / A converter 26, the memory 30, and the compression / expansion circuit 32. The image data output from the A / D converter 16 is written to the image display memory 24 or the memory 30 via the image processing circuit 20, the memory control circuit 22, or only the memory control circuit 22.

The image data for display written in the image display memory 24 is displayed by the image display unit 28 composed of a TFT type LCD or the like via the D / A converter 26. The electronic viewfinder (EVF) function can be realized by sequentially displaying the captured image data using the image display unit 28.

The memory 30 is a memory for storing captured still images and moving images, and has a sufficient storage capacity for storing a predetermined number of still images and moving images for a predetermined time. As a result, even in the case of continuous shooting imaging, it is possible to write a large amount of images at high speed to the memory 30. The memory 30 can also be used as a work area of the system control circuit 50. Further, the memory 30 is also used to store the relative information of the focus control circuit 42 with respect to the operation of the zoom control circuit 44 that changes the magnification of the subject image. The zoom control circuit 44 controls the zoom lens 10 to change the focal length.

The compression / decompression circuit 32 that compresses and decompresses an image that has been processed by reading image data stored in the memory 30 and performing compression processing or decompression processing by using a known compression method such as adaptive discrete cosine transform (ADCT). The data is written to the memory 30 again.

The system control circuit 50 incorporates a well-known CPU or the like and controls the entire camera body 100. In the present embodiment, the system control circuit 50 includes a light measurement result acquisition unit 500, a focus detection condition calculation unit 501, a lens angle of view detection unit 502, an AF frame setting unit 503, a subject image plane movement amount calculation unit 504, and a pixel information acquisition unit. 505, the focus detection area setting unit 506 is provided.

The photometric result acquisition unit 500 acquires the photometric result from the exposure control circuit 40. The lens angle of view detection unit 502 (angle of view information acquisition means) acquires the focal length information of the lens unit 150 mounted on the camera body 100 from the zoom control circuit 44, and detects the angle of view information of the lens. The pixel information acquisition unit 505 acquires pixel information such as the number of recorded pixels and the aspect ratio of the image sensor 14 recorded in the memory 65, or the allowable number of pixels of subject image blur that can be determined to be in focus.

The focus detection condition calculation unit 501 acquires the focal state based on the lens angle of view information acquired by the photometric result acquisition unit 500, the lens angle of view detection unit 502, and the pixel information acquired by the pixel information acquisition unit 505. , The exposure time, the time required for AF processing, etc. are calculated by calculation.

The subject image plane movement amount calculation unit 504 is the distance that the subject image, which moves at a constant speed at a predetermined speed, moves on the imaging surface during the AF processing from the time required for the AF processing obtained by the focus detection condition calculation unit 501. Is calculated.

When the AF frame setting unit 503 displays the AF frame, which is an index for framing the subject to be focused on during AF, on the image display unit 28, the AF frame setting unit 503 moves the subject image on the imaging surface at a predetermined speed during the AF process. The position and size of the AF frame are set based on the movement distance information.

The focus detection area setting unit 506 acquires the focus evaluation value of the subject to be focused based on the maximum movement distance information of the subject image moving on the imaging surface at a predetermined speed during AF processing. And set the size.

The memory 65 stores constants, variables, programs, and the like for the operation of the system control circuit 50. The exposure control circuit 40 controls an aperture shutter unit 13 having an aperture function and a shutter function, and a gain amplifier 120 for setting the imaging sensitivity. As the non-volatile memory 66, a storage medium such as a flash ROM that can be electrically erased and recorded is used.

The exposure control circuit 40 and the focus control circuit 42 are controlled by using the TTL method as described above, and the system control circuit 50 determines the exposure control circuit 40 and the focus based on the calculation result obtained by calculating the captured image data by the image processing circuit 20. Control is performed on the control circuit 42.

The notification unit 63 includes a liquid crystal display device, a speaker, and the like that display an operating state, a message, and the like using characters, images, voices, and the like according to the execution of a program by the system control circuit 50. The notification unit 63 is installed at one or more locations near the operation unit of the camera body 100 so that it can be easily seen.

Among the display contents of the notification unit 63, the following are displayed on the LCD or the like. First, there are displays related to shooting modes such as single shooting / continuous shooting imaging display and self-timer display. In addition, there are displays related to recording such as compression rate display, recording pixel number display, recording number display, and remaining imageable number display. In addition, there are displays related to shooting conditions such as shutter speed display, aperture value display, exposure compensation display, flash display, and red-eye mitigation display. In addition, there are macro imaging display, buzzer setting display, battery level display, error display, information display by a plurality of digits, and attachment / detachment state display of the recording medium 200. Further, the attachment / detachment state display of the lens unit 150, the communication I / F operation display, the date / time display, the display showing the connection state with the external computer, and the like are also performed.

The shutter switch SW1 (60) is turned on during the operation (for example, half-pressing) of a shutter switch member (not shown), and images such as AF (autofocus) processing, AE (autoexposure) processing, and AWB (auto white balance) processing are taken. Instructs the start of preparatory operation.

The shutter switch SW2 (61) is turned on when the operation of the shutter switch member (not shown) is completed (for example, fully pressed), and instructs the start of a series of processes including the exposure process, the developing process, and the recording process. In the exposure process, the signal read from the image sensor 14 is written to the memory 30 via the A / D converter 16 and the memory control circuit 22, and further, the image processing circuit 20 and the memory control circuit 22 perform calculations. The development process used is performed. Further, in the recording process, the image data is read from the memory 30, compressed by the compression / decompression circuit 32, and the image data is written to the recording medium 200.

The operation unit 62 includes various buttons, a touch panel, and the like, and has a menu button, a set button, a macro button, a multi-screen playback page break button, a strobe setting button, and a single shooting / continuous shooting / self-timer switching button. Further, the operation unit 62 responds to various shooting scenes such as an auto mode, a program mode, an aperture priority mode, a shutter speed priority mode, an astronomical shooting mode, a night view mode, a child shooting mode, a fireworks shooting mode, and an underwater shooting mode. You can select the settings you want.

Further, the operation unit 62 includes a menu move + (plus) button, a menu move- (minus) button, a playback image move + (plus) button, a playback image- (minus) button, an image quality selection button, an exposure compensation button, and a date. It has an attach / time setting button.

The power supply control circuit 80 includes a battery detection circuit, a DC-DC converter, a switch circuit for switching a block to be energized, and the like. Then, the power supply control circuit 80 detects whether or not a battery is installed, the type of battery, the remaining battery level, and the power supply voltage, and controls the DC-DC converter based on the detection result and the instruction of the system control circuit 50, which is necessary. A voltage is supplied to each part including the recording medium for a required period.

The power supply 86 includes a primary battery such as an alkaline battery or a lithium battery, a secondary battery such as a NiCd battery, a NiMH battery, or a Li battery, an AC adapter, or the like. The power supply control circuit 80 and the power supply 86 are connected via connectors 82 and 84.

As the interface 90 and the connector 92, those conforming to a standard such as a Secure Digital (SD (registered trademark)) card may be used. Further, the interface 93 is prepared for connecting to another device for communication, and communicates with the other device by connecting directly via the connector 94 or by connecting with a communication cable. The wireless communication unit 98 is connected to the interface 93 inside the camera body 100 and wirelessly communicates with other devices.

The recording medium 200 includes a recording unit 202 composed of a semiconductor memory, a magnetic disk, or the like, an interface (I / F) 204 with the camera body 100, and a connector 206 for connecting to the camera body 100.

In the above, the lens unit 150 is described as a detachable configuration, but it goes without saying that there is no problem in carrying out the present invention even if the lens unit 150 is not detachable.

Hereinafter, the operation of the image pickup apparatus having the above configuration will be described. FIG. 2 is a diagram for explaining the relationship between the angle of view of the lens and the amount of movement of the subject on the imaging surface.

When the size of the image sensor 14 is a and the focal length of the lens is b, the angle of view θ of the lens is calculated as follows.

θ = 2 * arctan ((a / 2) / b) [rad]

That is, the angle of view θ increases as the size a of the image sensor increases, while the angle of view θ decreases as the focal length b increases.
Here, when the subject is a celestial body, it rotates about 15 degrees per hour with respect to the polar axis of the earth due to diurnal motion. For example, if the angle at which the celestial body rotates due to diurnal motion at an arbitrary time is γ, the image of the celestial body on the imaging surface also moves by γ with respect to the angle of view θ. Let c be the moving distance of the subject image on the imaging surface. That is, even if the angle γ at which the celestial body moves due to diurnal motion is the same, the angle of view θ of the captured image becomes narrower as the lens focal length b becomes larger, so that the moving distance c of the subject image on the imaging surface is relatively Indicates that it will grow.

FIG. 3 is a diagram illustrating the relationship between the focus detection range 301 and the AF frame 302 in the imaging range 300, and the divided regions 1 to 9 obtained by dividing the focus detection range 301 into one or a plurality of parts. FIG. 3 shows, as an example, a case where the focus detection range 301 is divided into 9 divided regions 1 to 9. Further, in FIG. 3, the focus detection range 301 and the AF frame 302 are shown as different sizes, but the size and shape of the focus detection range 301 and the AF frame 302 can be changed depending on the shooting conditions and the subject. ..

FIG. 4A is a diagram illustrating the relationship between the focus detection range 301, the AF frame 302, and the divided regions 1 to 9 when focusing on a celestial body with a lens having a focal length of about wide-angle to medium telephoto. When focusing on a celestial body, the focus lens is moved by a predetermined amount converted to the depth of focus near the infinite focus position, and the focus evaluation value is detected for each of all the divided areas 1 to 9, and the focus evaluation value is the highest. The position of the focus lens is detected as the in-focus position. In this case, each divided region is treated as a focus detection region. As a result of detecting the focusing position of each of the divided regions 1 to 9, in the example shown in FIG. 4B, the divided regions 2, 6 and 7 having low reliability are not used for the focusing determination, and the remaining divided regions are used. AF is completed by moving the focus lens 12 to the representative focusing position detected from 1, 3, 4, 5, 8, and 9. As the representative focusing position, for example, the average position of the focusing position detected by a plurality of frames that can be used for focusing determination, the most frequent focusing position, the farthest focusing position, and the like, the focus is highly reliable. It may be obtained based on the focus position.

The low-reliability division region is, for example, a division region in which changes in the focus evaluation values detected at a plurality of focus lens positions increase or decrease discontinuously or the focus evaluation value is lower than a predetermined level. If the change in the focus evaluation value increases or decreases discontinuously, the subject image may deviate from each divided area or the subject image may enter the divided area in the middle while acquiring the focus evaluation values multiple times. Cases are assumed. When the focus evaluation value is lower than the predetermined level, it is assumed that the contrast of the subject image is low, the celestial body is not included, or the image is not taken with an appropriate exposure.

Here, as a characteristic when photographing an astronomical object, in the case of a wide-angle lens, the amount of movement on the imaging surface due to the diurnal motion of the astronomical object is small, and the astronomical object moves in and out of each divided region during focusing (during AF). Is few. Also, even if a celestial body comes out of the divided area during AF or enters in the opposite direction, if the number of stars coming out of the divided area and the number of stars entering during AF are about the same. Does not have to be determined as an unreliable divided area. Especially in the case of a wide-angle lens, the number of stars reflected on the imaging surface is large and the density of stars is high, so assuming that the density of stars in the night sky is uniform, the stars that go out and the stars that come in during AF The number of can be considered to be comparable.

Therefore, in the present embodiment, in the case of a lens having a focal length of about wide-angle to medium telephoto, the focal length detection range 301 and the AF frame 302 are set to have the same size as shown in FIG. However, since the peripheral portion of the imaging range 300 is affected by dimming characteristics and coma aberration, the focus detection range 301 is limited in consideration of these effects.

FIG. 5 is a diagram for explaining the relationship between the focus detection range 301 and the AF frame 302 when focusing on a celestial body with a telephoto lens. As described above, when shooting with a telephoto lens, the angle of view of the captured image is narrower than when shooting with a lens with a focal length of about wide-angle to medium telephoto, so it is relatively on the imaging surface. The moving distance of the subject image increases.

Therefore, in the present embodiment, the size of the AF frame 302 is narrowed from the focus detection range 301 by the distance that the subject image moves on the imaging surface during AF. By displaying the AF frame 302 in this way and keeping the celestial body to be focused by the photographer in the AF frame 302, even if the celestial body moves due to diurnal motion during AF, the celestial body to focus from the focus detection range 301 Can be prevented from appearing.

6 and 7 are diagrams illustrating an example of a method of setting a focus detection region with respect to the focus detection range 301 when AF is performed with a telephoto lens.

As described with reference to FIG. 5, the size of the AF frame 302 is set so that the subject image does not go out from the focus detection range 301 until AF is completed. On the other hand, as described with reference to FIG. 2, as the focal length increases, the angle of view of the captured image becomes narrower, so that the moving distance of the subject image on the imaging surface becomes relatively large. Therefore, when trying to detect the focusing position for each divided region, it is assumed that the celestial body moves over a plurality of divided regions depending on the moving direction of the celestial body. Therefore, when AF is performed with a telephoto lens, the in-focus position is detected by using a region in which the divided regions are connected as one focus detection region.

FIG. 6A is a diagram showing a case where the divided regions 1, 2, 4, and 5 shown in FIG. 3 are used as one focus detection region. Similarly, FIG. 6B is a diagram showing a case where the divided regions 2, 3, 5, and 6 shown in FIG. 3 are used as one divided region. Further, FIG. 7 (a) shows the case where the divided regions 4, 5, 7, and 8 shown in FIG. 3 are used as one divided region, and FIG. 7 (b) shows the divided regions 5, 6 shown in FIG. , 8 and 9 are shown as one divided area. By making the four divided regions overlap including the central region of the imaging range in this way, the focusing position of each focus detection region even when the moving distance of the subject image on the imaging surface becomes large. I am trying to be able to ask for. Then, the representative focusing position is detected by excluding the focusing position of the unreliable focus detection region from the obtained focusing positions of each focus detection region as described above.

FIG. 8 is a diagram for explaining the relationship between the AF frame 302 and the focus detection range 301 when focusing on a celestial body with a super-telephoto lens having a focal length longer than that shown in FIG. The size of the AF frame 302 is set by the method described with reference to FIG. Further, as the focus detection area, the divided areas 1 to 9 are combined into one focus detection area without dividing the focus detection range 301.

In the case of a super-telephoto lens, the moving distance of the subject image on the imaging surface is further increased, but the density of the stars is reduced, so that other stars may enter the focus detection area during the AF period. Almost none. Further, the exposure condition during AF is set to such a brightness that the dark star does not affect the focus evaluation value, so that the focus can be detected.

FIG. 9 is a flowchart illustrating a flow of AF processing for focusing on a celestial body in the present embodiment. The lens angle of view detection unit 502 acquires the angle of view information from the zoom control circuit 44 (S100), and then the pixel information acquisition unit 505 acquires pixels such as the number of pixels of the image sensor 14 and the size of the image pickup area from the memory 65. Acquire information (S101). Based on this information, the number of pixels that the celestial body that moves by diurnal motion moves per predetermined time is calculated with respect to the lens angle of view information acquired in S100. Further, when AF is performed on the celestial body, the maximum exposure time for the number of pixels that can be tolerated even if the celestial body moves is calculated, and the exposure condition at the time of AF is calculated (S102).

Based on this information, the focus detection condition calculation unit 501 calculates the number of focus detections and the shutter speed as the focus detection condition (S103), and calculates the time required until AF is completed (detection time) (S104). .. Here, the detection time is the time required to complete a plurality of exposures while moving the focus lens. The AF frame setting unit 503 calculates the distance that the star of the subject image moves on the imaging surface based on the time required for AF to be completed based on the conditions calculated in S104 (S105). Then, a region whose width is narrowed from the four sides of the focus detection range 301 by the calculated distance is set as the display size of the AF frame 302 (S106).

Here, when the calculated display size of the AF frame 302 is smaller than the predetermined size required for AF, it is determined that AF cannot be performed (NG in S107), and an AF non-progress notification is displayed on the display unit (S110). In this case, the focus lens 12 is moved to a preset infinite position as the focus lens position (S111), and the AF process is completed.

On the other hand, when it is determined that AF is possible by the AF frame 302 calculated in S106 (OK in S107), focus detection processing is performed (S108), and the focus lens 12 is moved to the in-focus position (S109). The AF process is finished.

FIG. 10 is a flowchart illustrating a flow of the focus detection process performed in S108 of FIG. Here, the number of focus detections is set to f, and the number of focus detection regions is a.

First, the focus detection count counter M is initialized (S200), and the focus detection region counter N is initialized (S201). Then, the focus lens 12 is moved to the first focus detection start position, and the counter M is incremented by 1 (S202). Next, a focus detection area is set (S203). The focus detection region is set based on the focal state of the lens unit 150, as described with reference to FIGS. 5 to 8. Details of the processing performed in S203 will be described later with reference to FIG. Then, one focus evaluation value is detected for each focus detection region (S204), and the processes of S204 and S205 are repeated until a total of a focus evaluation values are obtained for all the divided regions (S205).

Similarly, until the number of focus detections reaches f times (No in S206), the process returns to S201, the focus lens 12 is moved, and a focus evaluation value of a x f times is acquired. When the number of focus detections reaches f times (Yes in S206), the unreliable focus detection region is excluded so as not to be used for the focusing determination, and a valid focus detection region is detected (S207). The focus position of the focus lens 12 is detected based on the focus evaluation value obtained from the effective focus detection region detected in S207, and the focus detection process is terminated.

FIG. 11 is a flowchart illustrating a flow of a focus detection region setting process performed in S203 of FIG. In S300, the angle of view information of the lens is acquired, and when the angle of view of the lens is larger than the first threshold angle (Yes in S301), a small-sized focus detection area is set by dividing the focus detection range 301 into w pieces. (S302). In this case, for example, the focus detection range 301 is divided and each divided area is set as the focus detection area as described with reference to FIG.

On the other hand, when the angle of view of the lens is equal to or less than the first threshold angle in S301 (No in S301), it is compared with a predetermined second threshold angle smaller than the first threshold angle. If the angle of view of the lens is larger than the second threshold angle (Yes in S303), a focus detection area larger than the focus detection area determined in S302 is set (S304). The number t of the focus detection region at this time is set to be less than w. In this case, for example, the focus detection region is set as described with reference to FIGS. 6 and 7.

When the angle of view in S303 is smaller than a predetermined threshold value for determining the angle of view of a lens different from S301 (No in S303), a focus detection area larger than the focus detection area determined in S304 is set (S305). .. At this time, for example, as described with reference to FIG. 8, one focus detection area having the same size as the focus detection range 301 is set.

In the above-described example, the case where the size of the focus detection region is determined by comparing the angle of view of the lens with the threshold value has been described, but the size of the focus detection region may be determined based on the focal length of the lens. In that case, the longer the focal length, the narrower the angle of view. Therefore, the longer the focal length, the larger the size of the focus detection region may be controlled.

In the above-described embodiment, it has been described that the size of the focal detection range 301 is set according to the characteristics of the lens, but the present invention is not limited to this. For example, if it is within the imaging range 300, the focus detection range 301 can be expanded and AF can be performed by changing the weighting of the focus evaluation value according to the lens characteristics.

Further, in the present embodiment, it has been described that the number and size of the divided regions are changed according to the angle of view of the lens. However, even with a wide-angle lens, the AF frame 302 is focused and detected by calculating the distance that the celestial body moves in the time until the AF processing is completed (the time until the multiple exposures are completed while moving the focus lens). The size may be narrowed from the range 301.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof.

<Other embodiments>
The present invention may be applied to a system composed of a plurality of devices or a device composed of one device.

The present invention also supplies a program that realizes one or more functions of the above-described embodiment to a system or device via a network or storage medium, and one or more processors in the computer of the system or device implement the program. It can also be realized by the process of reading and executing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

10: Variable magnification lens, 12: Focus lens, 14: Imaging element, 28: Image display unit, 50: System control circuit, 100: Camera body, 150: Lens unit, 500: Photometric result acquisition unit, 501: Focus detection condition Calculation unit, 502: Lens angle detection unit, 503: AF frame setting unit, 504: Subject image plane movement amount calculation unit, 505: Pixel information acquisition unit, 506: Focus detection area setting unit

Claims (18)

Pixel information acquisition means for acquiring pixel information including the number of pixels of an image sensor and the size of an image pickup region that receives light incident on the photographing optical system and outputs an image signal.
An angle-of-view information acquisition means for acquiring information on the angle of view of the photographing optical system,
A range setting means for setting a focus detection range, which is a region used for focus detection on the image pickup surface of the image sensor, and
A focus detection means that detects a focus evaluation value based on an image signal obtained from the focus detection range and detects a focusing position of the photographing optical system based on the focus evaluation value.
A calculation means for obtaining the distance that an image of a subject moving during the detection time moves on the imaging surface based on the information on the angle of view, the detection time required for detecting the focus evaluation value, and the pixel information. When,
A focus detection device comprising: a frame setting means for setting a frame representing a range in which the focus detection range is narrowed by the distance to be displayed on a display means for displaying the image signal. Photometric means and
The focus detection device according to claim 1, further comprising an arithmetic means for calculating the detection time based on the information on the angle of view, the pixel information, and the photometric result. The angle of view information acquisition means acquires the focal length of the photographing optical system, obtains the angle of view based on the acquired focal length, and obtains the angle of view.
The focus detection device according to claim 1 or 2, wherein the calculation means obtains the distance by using the angle of view as information regarding the angle of view. The aspect according to any one of claims 1 to 3, wherein when the frame set by the frame setting means is smaller than a predetermined size, the focus detecting means does not detect the frame. Focus detector. The focus detecting means detects the in-focus position for each of the focus detection regions set in the focus detection range based on the information about the angle of view, and based on the in-focus position, the in-focus position of the photographing optical system. The focus detection device according to any one of claims 1 to 4, wherein the focus detection device is characterized in that. The focus detecting means takes a picture based on the remaining focus positions of each focus detection region excluding the focus positions determined to be unreliable based on predetermined conditions. The focus detection device according to claim 5, wherein the focus position of the optical system is detected. Has an area setting means for setting a focus point detecting area, to claim 5 or 6, characterized in that to set the focus detection area in the focus detection range based on the information region setting means for said angle The focus detector described. The information regarding the angle of view is the angle of view of the photographing optical system.
The claim is characterized in that when the angle of view is wider than a predetermined first threshold value, the size of the focus detection region is smaller and the number is larger than when the angle of view is not wide. Item 7. The focus detection device according to item 7. The region setting means is characterized in that the focus detection range is set as the focus detection region when the angle of view is narrower than a predetermined second threshold value narrower than the first threshold value. The focus detection device according to claim 8. The information regarding the angle of view is the focal length of the photographing optical system.
The claim is characterized in that when the focal length is shorter than a predetermined first threshold value, the size of the focal length detection region is smaller and the number is larger than when the focal length is not short. Item 7. The focus detection device according to item 7. The region setting means is characterized in that the focal length is set as the focal detection region when the focal length is longer than a predetermined second threshold that is longer than the first threshold. The focus detection device according to claim 10. The focus detection device according to any one of claims 1 to 11, wherein the subject is an astronomical object. An image sensor that receives light incident through the photographing optical system and outputs an image signal,
A display means for displaying the image signal and
An imaging device comprising the focus detection device according to any one of claims 1 to 12. The imaging device according to claim 13, wherein the imaging device is removable from the photographing optical system. The imaging device according to claim 13, further comprising the photographing optical system. A pixel information acquisition step in which the pixel information acquisition means acquires pixel information including the number of pixels of an image sensor that receives light incident through a photographing optical system and outputs an image signal and the size of an image pickup region.
An angle-of-view information acquisition step in which the angle-of-view information acquisition means acquires information on the angle of view of the photographing optical system, and
A range setting step in which the range setting means sets a focus detection range, which is a region used for focus detection on the image pickup surface of the image sensor, and a range setting step.
A focus detection step in which the focus detection means detects a focus evaluation value based on an image signal obtained from the focus detection range and detects a focus position of the photographing optical system based on the focus evaluation value.
The distance by which the image of the subject moving during the detection time moves on the imaging surface based on the information on the angle of view, the detection time required for detecting the focus evaluation value, and the pixel information. And the calculation process to find
The focus detection means includes a frame setting step of setting a frame representing a range in which the focus detection range is narrowed by the distance to be displayed on the display means for displaying the image signal. Method. A program for causing a computer to function as each means of the focus detection device according to any one of claims 1 to 12. A computer-readable storage medium that stores the program according to claim 17.

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