JP2000155261A - Focus detecting method, focus detector and storage medium storing focus detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a situation that focus detection is impossible and to realize high-speed operation in arithmetic operation time by changing a focus detection arithmetic method in accordance with a setting condition for photographing. SOLUTION: A diaphragm for focus detection 3 has two aperture parts (hereinafter referred to as a left-side pupil and a right-side pupil) having the same shape in a horizontal direction in order to perform a pupil time division phase difference AF. In the case of focus detection, the diaphragm 3 is inserted in the optical path of a photographing lens by a motor 4, and a light shielding plate 5 is moved by a motor 6 so as to shield either the left-side pupil or the right-side pupil from light, whereby an optical image consisting of luminous flux passing through the different pupil is formed on a CCD 9. Namely, in order to perform the pupil time division phase difference AF, the diaphragm 3 is inserted in the optical path according to designation from a system control part 13. By using the appropriate focus detection arithmetic method in accordance with the setting condition of a camera in such a way, the situation that the focus detection is impossible is restrained and the high-speed operation in the focus detection arithmetic operation time is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a focus detection method for an image pickup apparatus using an image pickup device such as a digital camera, a focus detection apparatus, and a storage medium storing the focus detection method.

[0002]

2. Description of the Related Art Conventionally, a large number of phase difference detection type focus detection devices have been used as automatic focus devices used in single-lens reflex type silver halide cameras and the like.

FIG. 15 is a cross-sectional view of a single-lens reflex camera having a conventional focus detection device of a phase difference detection method. A light beam 109a emitted from a photographing lens 101 is reflected by a main mirror 102 made of a half mirror. It is divided into a light beam 109b and a light beam 109e to be transmitted. Reflected light beam 10
Numeral 9b forms an image of a subject on the diffusion surface of the focus plate 103, and the photographer observes the subject image on the focus plate via the eyepieces 105a and 105b and the ender prism 104.

The light beam 109e transmitted through the main mirror 102 is reflected by the sub mirror 106, and
The focus detection device 107 detects a focus state (a defocus amount) of the photographing lens 101 with respect to the silver halide film 108 based on a light beam 109f from the photographing lens 101.

When the detected defocus amount is larger than a predetermined focusing width and it is determined that the subject is out of focus, the photographing lens 101 is moved so as to cancel the detected defocus amount.
The focus adjustment lens is driven to adjust the focus.

Next, the focus detection principle of the conventional focus detection device will be described with reference to FIGS. FIG. 16A shows a focused state, that is, a focused state, in which light beams 116a and 116a passing through two different pupils of the photographing lens 110 are shown.
Reference numeral 116b forms an image on the primary image forming surface 114, and the subject image on the primary image forming surface is re-imaged by the secondary image forming lenses 112a and 112b on a sensor surface on which two line sensors 113a and 113b are arranged. . Here, the field lens 111 is disposed near the primary imaging plane of the photographing lens 110, and efficiently guides a light beam having a predetermined image height to the sensor surface,
It is possible to prevent a decrease in the amount of light that occurs with an increase in the image height.

Generally, the two light beams 116a and 116b passing through different pupils of the photographing lens 110 are defined by apertures (not shown) disposed immediately before or immediately after the secondary imaging lenses 112a and 112b. The photographing lens 10 does not have a member for dividing the pupil.

[0008] The two images formed on the line sensors 113a and 113b are luminous fluxes having passed through different pupils.
As shown in FIGS. 16 and 17, the relative position of the image differs in each of the in-focus state, the front focus state, and the rear focus state depending on the extension amount of the lens.

FIGS. 16 (a) and 17 (a) show the distance between two images formed on the line sensors 113a and 113b at the time of focusing, and the relative distance between the two line sensors. It is equal to e0 and is always constant at the time of focusing.

FIGS. 16 (b) and 17 (b) show a state in which the front focus state is set by the defocus amount d1 and the distance el between the two images.
Is smaller than e0, and if the defocus amount dl increases, the difference δ1 between e0 and el also increases.

FIGS. 16 (c) and 17 (c) show a state in which the back focus state is set by the defocus amount d2, and the distance e2 between the two images.
Is greater than e0. When the defocus amount d2 increases, the difference δ2 between e2 and e0 also increases.

As described above, the magnitude and direction of the defocus amount at that time can be determined from the interval between the two images.

Accordingly, the difference between the distance e between the two images in the current defocus state and the reference image distance e0 at the time of focusing, that is, the relative shift amount (phase difference) δ between the two images is: ee
0 is calculated by correlating the output signals of the two line sensors 113a and 113b, the defocus amount and the direction of the optical system are obtained from the phase difference, and the focus lens is controlled to perform focusing. .

[0014]

However, as the defocus amount d increases, the phase difference δ also increases, so that the zoom state (the focal length of the photographing lens when performing focus detection) and the subject distance for performing focus detection are determined. The focus detection calculation method suitable for the focus detection at that time changes depending on the setting conditions of the camera such as the range.

For example, the range of the subject distance for which focus detection can be performed can be set by selecting one of a normal mode (non-macro mode) and a macro mode. In addition to the range, when the closest end can be detected up to the closer side, the macro mode uses the same focus detection method as the non-macro mode because the maximum defocus amount is larger than the non-macro mode. In, the search range of the image signal of the correlation operation for obtaining the phase difference is smaller than the maximum phase difference in the macro mode,
Depending on the subject distance, focus detection may not be possible.

Further, depending on the mode, the range of the subject distance for which focus detection is performed changes, and even though the maximum defocus amount is different, if the same correlation calculation is performed, extra calculation is required, and the calculation time is increased. Cost. Considering the time required for focus detection, the shorter the calculation time, the better, and there is a problem in using the same focus detection calculation method under any conditions.

An object of the invention according to the present application is to perform a focus detection calculation for obtaining a phase difference using a phase difference detection signal for focus detection, and to perform an appropriate focus detection operation in accordance with the camera setting conditions at that time. An object of the present invention is to prevent the focus detection from being disabled by using the calculation method. Another object is to shorten the operation time.

[0018]

According to the present invention, there is provided a focus detection method, wherein a light beam passing through at least two different pupil regions of a photographing optical system is imaged on an image sensor, and at least two light beams obtained from the image sensor are obtained. A focus detection method for obtaining a phase difference between two output images, wherein a calculation method of the focus detection is changed according to a setting condition of photographing. In addition, the focus detection device of the present invention forms a light beam that has passed through at least two different pupil regions of an imaging optical system on an image sensor, and calculates a phase difference between at least two output images obtained from the image sensor. A focus detection device to be sought, wherein a calculation method of the focus detection is changed according to a setting condition of photographing. In addition, the focus detection device of the present invention includes: an imaging unit that forms a light beam that has passed through at least two different pupil regions of an imaging optical system on an imaging element; and at least two output images obtained from the imaging element. And a calculation means for changing the calculation method of the focus detection in accordance with the setting conditions of photographing.

This makes it possible to prevent the focus detection from becoming impossible. In addition, it is possible to use a focus detection calculation method suitable for the setting conditions at that time, and it is possible to omit extra calculation compared to when one focus detection calculation method is used in all cases. Can be measured.

In one embodiment of the focus detection method of the present invention, at least two ranges of the subject distance can be set, and the setting conditions for the photographing are the range settings of the subject distance. In one aspect of the focus detection device of the present invention, at least two ranges of the subject distance can be set, and the setting condition of the photographing is the range setting of the subject distance.

This makes it possible to use a focus detection calculation method suitable for the range of the subject distance in which focus detection is possible, to prevent the focus detection from being disabled, and to use one focus detection calculation method. Since unnecessary calculation can be omitted as compared with the case of using in the case of (1), the calculation time can be shortened.

In one embodiment of the focus detection method according to the present invention, one of the subject distance ranges is set wider on the closest side than the other subject distance ranges. Also,
In one aspect of the focus detection device of the present invention, one of the ranges of the subject distance is set wider on the closest side than the range of the other subject distances.

With this, it is possible to change to a focus detection calculation method that matches the maximum phase difference detected at the time of phase difference detection according to the set subject distance range in which focus detection is possible. Since it is possible to prevent the detection from being disabled and to eliminate unnecessary calculations as compared with the case where one focus detection calculation method is used in all cases, the calculation time can be shortened.

In one embodiment of the focus detection method according to the present invention, the photographing setting condition is a focal length of the photographing optical system. In one aspect of the focus detection device of the present invention, the setting condition of the photographing is a focal length of the optical system for photographing.

As a result, even when the image magnification changes or the maximum defocus amount changes due to a change in the focal length, it is possible to use a focus detection calculation method suitable for the set conditions at that time. As compared with the case where one focus detection calculation method is used in all cases, unnecessary calculation can be omitted, so that the calculation time can be shortened.

In one embodiment of the focus detection method according to the present invention, a search range along the optical axis direction of the optical system of the output image at the time of detecting the output image is changed according to the setting condition of the photographing. In one aspect of the focus detection device of the present invention, a search range along the optical axis direction of the optical system of the output image at the time of detecting the output image is changed according to the setting condition of the imaging. ing.

Thus, when the maximum defocus amount is large, the search range for detecting the phase difference can be increased, and when the maximum defocus amount is small, the search range can be reduced. Based on the previous defocus amount,
By setting the next search range, unnecessary calculations can be omitted, and the calculation time can be shortened.

In one embodiment of the focus detection method according to the present invention, a step amount of a signal of the output image at the time of detecting the output image is changed according to the setting condition of the photographing. In one aspect of the focus detection device of the present invention, the step amount of the signal of the output image at the time of detecting the output image is changed according to the setting condition of the imaging.

Thus, if the focus detection accuracy can be low, the number of steps is increased, and if the focus detection requires high accuracy, the number of steps is reduced to meet the required focus detection accuracy. Calculation can be performed, and the calculation time can be shortened.

In one embodiment of the focus detection method according to the present invention, the size of the area of the output image on the image sensor is changed according to the setting conditions of the photographing. In one aspect of the focus detection device of the present invention, the size of the area of the output image on the image sensor is changed according to the setting condition of the imaging.

As a result, it is possible to change the area of the subject used for focus detection, thereby improving the focus detection accuracy and eliminating unnecessary calculations, thereby shortening the calculation time.

In one embodiment of the focus detection method according to the present invention, whether or not to perform a shift operation in a direction perpendicular to a defocus direction of the optical system is changed according to the setting condition of the photographing. In one embodiment of the focus detection device according to the present invention, whether or not to perform a shift operation in a direction perpendicular to a defocus direction of the optical system is changed according to a setting condition of the photographing.

By performing the shift operation in the direction perpendicular to the phase shift direction generated according to the defocus amount, the shift operation in this direction can be omitted when the focus detection accuracy is deteriorated. As the focus detection accuracy is increased and unnecessary calculations can be omitted, the calculation time can be shortened.

In one embodiment of the focus detecting method according to the present invention, the data of the output image is thinned out according to the setting conditions of the photographing. In one aspect of the focus detection device of the present invention, the data of the output image is thinned out in accordance with the setting conditions of the imaging.

This makes it possible to change the method of thinning out the data used for the correlation calculation in accordance with the required focus detection accuracy according to the setting conditions of photographing, so that unnecessary calculation can be omitted. Speeding up is possible.

In one embodiment of the focus detection method according to the present invention, the light flux is imaged on the image sensor in a time-series manner. In one embodiment of the focus detection device according to the present invention, the light flux is formed on the image sensor in a time-series manner.

In one embodiment of the focus detecting method according to the present invention, the imaging means divides a photographing light beam of the photographing optical system into at least two regions in time series, and There is further provided pupil position moving means for projecting an image composed of light beams passing through different pupil regions of the system onto the image pickup device.

That is, as means for forming an optical image composed of light beams having passed through two different pupil areas of the optical system on the image pickup device, at least two light beams of the photographing optical system are used.
Pupil position moving means for projecting an image composed of a light beam passing through different pupil regions of the photographing optical system onto the image pickup device by dividing the image pickup device into two regions in a time series manner. As a pupil splitting means for realizing the dual use of a sensor for use, a small space, cost reduction and improvement of focus detection accuracy can be achieved.

The storage medium of the present invention is a computer-readable storage medium storing a program for causing a computer to execute the procedure of the focus detection method.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a view showing an embodiment of a focus detection device and a camera using the same according to the present invention.
Reference numeral a denotes a lens group other than the focusing lens group 1b of the photographing lens, and reference numeral 2 denotes a lens extension mechanism for extending the focusing lens group 1b, which includes a motor for moving the lens. Reference numeral 3 denotes a focus detection aperture, 4 denotes a motor for inserting the focus detection aperture into the optical path, 5 denotes a light shielding plate for shielding one of two openings in the focus detection aperture, and 6 denotes light shielding. It is a motor for moving the board. 7 is an optical low-pass filter, 8 is an infrared cut filter, 9 is a CC that converts an optical image into an electric signal by photoelectric conversion.
D.

Reference numeral 10 denotes an amplifier for amplifying the output from the CCD, 11 denotes an A / D converter for digitizing an analog signal amplified by the amplifier 10 with a predetermined gain, 12
Is a digital signal processing unit for performing various digital signal processing of the digital signal converted by 11, 13 is a system control unit for controlling the entire camera, and 14 is for controlling the driving of the CCD 9 and setting the amplification factor of the amplifier 10. C
Reference numeral 15 denotes a CD driver, which is a lens control unit that controls the extension of the focusing lens group 1b.

Reference numeral 16 denotes a buffer memory such as a DRAM used for temporarily storing digital signals, for example, a reference numeral 17 denotes a card slot connected to a recording medium or a function card and the like, and a control unit thereof, and reference numeral 18 denotes an electronic viewfinder. (EVF), 19 is a driver section of the LCD, 20 is a D / A converter for sending an analog signal to the driver section, 21 is an image holding an image to be displayed on the EVF, and outputs a digital signal to the D / A converter. VRAM,
Reference numeral 22 denotes an external black-and-white liquid crystal (LC) for displaying camera settings and the like.
D) and 23 are LCD drivers for displaying the LCD, and 24 is an operation switch for detecting a setting of a shooting mode of the camera and a release operation.

This embodiment will be described with reference to FIG. Here, the focus detection method and the focus detection device directly related to the present invention will be mainly described. Now, it is assumed that the power of the camera is turned on and the camera is in a photographable state. The focus detection aperture 3 is
In order to perform pupil time division phase difference AF, two openings having the same shape in the horizontal direction (hereinafter, the left opening is referred to as a left pupil and the right opening is referred to as a right pupil when viewed from the CCD 9 side). When the focus is detected, the light is inserted into the optical path of the photographing lens by the motor →, and the light shielding plate 5 is moved by the motor 6,
An optical image composed of light beams that have passed through different pupil areas can be formed on the CCD 9 by shielding either the left pupil or the right pupil.

Pupil time-division phase-difference AF (movable pupil is inserted into the photographing optical system, and the pupil is moved to form an optical image composed of light beams having different pupil regions on the photographing image sensor. (A phase difference method of detecting a phase difference between a plurality of images having different pupil regions and detecting a defocus amount of the photographing lens) by the instruction of the system control unit 13. Insert the aperture 3 for use. FIG. 2 is a diagram showing a positional relationship between the focus detection diaphragm 3 and the light shielding plate 5. FIG. 2A shows a state at the time of photographing, in which the focus detection diaphragm 3 and the light shielding plate 5 are at positions retracted outside the optical path of the photographing lens, and 25 is a pupil when the photographing lens of the photographing lens is opened. The shape is shown.

First, as shown in FIG. 2B, the right pupil 3b of the focus detecting aperture is closed with a light shielding plate 5, and an optical image composed of a light beam passing through the left pupil 3a of the photographing lens is formed on the CCD. And capture the image. At this time, the focus detection image data composed of the light beam that has passed through the left pupil 3a is referred to as a left image 1.

Next, in order to obtain focus detection image data composed of light beams passing through different pupil areas, the motor 6 is driven, and the light shielding plate 5 is moved as shown in FIG. An optical image composed of a light beam passing through the pupil 3b is formed on a CCD, and the image is captured. At this time, the focus detection image data composed of the light beam that has passed through the right pupil 3b is defined as the right image 2.

Further, in order to capture image data for focus detection consisting of a light beam having passed through the same left pupil 3a as the left image 1,
The light shielding plate 5 is moved again as shown in FIG.
An image to be formed on a CCD is captured. At this time, the image data for focus detection composed of the light beam that has passed through the left pupil 3a is referred to as a left image 3.

Similarly, the right image 4 and the left image 5 are taken.

The exposure for taking in the image data for focus detection is performed by using an electronic shutter, a mechanical shutter (not shown), adjusting the gain of the amplifier 10, adding and reading in the CCD described later, and, in some cases, using an auxiliary light. Every
The adjustment is performed by using them.

By the way, the left image 1, the right image 2, the left image 3, the right image 4, and the left image 5, which are image data for focus detection, are taken in and focus detection is performed. In order to reduce the focus detection error due to relative movement between the camera and the subject (such as camera shake or movement of the subject), it is desirable that the capture interval of each image be as short as possible. Therefore, when reading the entire screen of the CCD, as in the case of reading an image for shooting, it takes time to read out the image data for focus detection, so only a part of the image necessary for focus detection is read.
Reads out faster than in normal main shooting.

Such a reading method will be described below.
FIG. 3 shows a schematic view of an interline CCD. 31 is a pixel, 32 is a vertical charge transfer element, 33 is a horizontal charge transfer element, and 34 is an output unit. The signal charge photoelectrically converted by the pixel is sent to the vertical charge transfer element, and is sequentially transferred in the direction of the horizontal charge transfer element by four-phase drive pulses φV1, φV2, φV3 and φV4. The horizontal charge transfer element transfers the signal charges of one horizontal line transferred from the vertical charge transfer element to the output section by the two-phase driving pulses φH1 and φH2, where the signal charges are converted into voltages and output.

FIG. 4 is a schematic view of an image pickup area of a CCD.
In this embodiment, in order to speed up the read operation, only a read area necessary for focus detection is read at a normal speed, and in other cases, a sweep transfer for reading at a high speed is performed. 41 is
The areas used for focus detection and read out as usual, 42 and 43 are the first half and second half high-speed sweep transfer areas, respectively.

FIG. 5 is a timing chart for one vertical synchronizing period when the vertical charge transfer element of the CCD is driven in four phases. VD denotes a vertical synchronizing signal and a vertical blanking period is indicated by LOW potential, and HD denotes a horizontal synchronizing signal and a horizontal blanking period is indicated by LOW potential. φV1, φV2,
φV3 and φV4 denote four-phase driving pulses of the vertical charge transfer element, and 51 and 52 denote read pulses for transferring signal charges photoelectrically converted by the pixels to the vertical charge transfer element. Reference numerals 53 and 54 of the four-phase driving pulses indicate high-speed sweep transfer pulses for transferring the signal charges read to the vertical charge transfer elements in the areas 42 and 43 in FIG. 4 at high speed, respectively. By sweeping out the area other than the necessary reading area at high speed in this way, the speed of the partial reading operation can be increased.

When reading out the focus detection signal,
The signal charges of a plurality of lines are added using the horizontal charge transfer element 33, so that a plurality of lines can be added and read. This is to compensate for the lack of light amount that occurs at the time of focus detection because the pupils 3a and 3b of the focus detection aperture are smaller than when the shooting aperture is opened at the time of actual shooting.
It is used to increase the sensitivity together with the gain of the amplifier 3.

Using the focus detection image data left image 1, right image 2, left image 3, right image 4, and left image 5 which have been read out at high speed in this way, a correlation operation between the images is performed. Focus detection is performed by calculating the phase difference between each image.Unlike a monochrome sensor dedicated to focus detection, such as that used in single-lens reflex type silver halide cameras, an image sensor for shooting and focus detection are used. When a dual-purpose sensor is used, a color filter is built on a single-chip color sensor, which is an image sensor for shooting, so that the output signal from the CCD is used as a phase difference detection signal. Must perform signal processing.

Although it is possible to use the luminance signal generated by using the luminance signal processing circuit for photographing as the signal for detecting the phase difference, the luminance signal for photographing uses a predetermined matrix operation. Considering the time required for focus detection, it is better that the calculation processing time for generating the phase difference detection signal from the output signal of the image sensor is shorter, and the phase difference detection signal is obtained by using a photographing luminance signal processing circuit. There is a problem in calculating.

Hereinafter, a description will be given of a calculation process for obtaining a phase difference detection signal for focus detection from the output signal of the CCD. FIG. 6a is a diagram showing a color filter array formed on a CCD. Ye, C constituting color filter
When four colors of y, Mg, and G are added one pixel at a time, Ye +
Since Cy + Mg + G = 2B + 3G + 2R, the average of outputs of one block of adjacent 2 × 2 pixels is used as a phase difference detection signal.

Actually, as described above, line addition reading is possible at the time of reading from the CCD. Therefore, by performing 2-line addition reading, two vertical pixels are added in the CCD (FIG. 6B), and this analog signal is output. To A / D converter 1
1 to convert to a digital signal, and perform an operation of two pixels in the horizontal direction in the digital signal processing unit 12 (FIG. 6C) to obtain 2 × 2
A phase difference detection signal is obtained by averaging the outputs of one block of the pixel.

In FIG. 6, the pitch of the phase difference detection signal is p with respect to the pixel pitch p of the CCD.

In this embodiment, the vertical addition is
In order to improve the S / N, the vertical addition is performed in the CCD. However, the reading may be performed without performing the line addition, and the vertical addition may be performed by digital signal processing.

Next, the phase difference is obtained by performing a correlation operation using the phase difference detection signal thus obtained.

FIGS. 7, 8 and 9 are views for explaining the focus detection principle of the pupil time division phase difference AF according to the present invention. FIG. 7 shows a state where the subject is in focus, that is, a focused state,
In the photographing state shown in FIG. 7C, the light beam 27 transmitted through the photographing lens 1 is focused on the light receiving surface of the CCD 9, and the defocus amount is zero. FIG. 7A shows that the focus detection diaphragm 3 is inserted on the optical path of the taking lens, and the right pupil 3 is
b, while the left pupil 3a is opened, the light beam 27a passing through the left pupil 3a
Image at a position zero away from FIG. 7B shows a state where the left pupil 3a is shielded from light by the light shielding plate 5 and the right pupil 3b is opened.
The light flux 27b passing through the right pupil 3b forms an image at a position zero away from the optical axis 26 on the light receiving surface of the CCD 9. As described above, in the focused state, the optical images composed of the light beams that have passed through the two different pupils 3a and 3b are both incident on the light receiving surface of the CCD 9 from the optical axis 26 at the same zero position. Is zero.

FIG. 8 shows a state in which the defocus amount is in the front focus state by d. In the photographing state shown in FIG. 8C, the light beam 27 transmitted through the photographing lens 1 is focused on the light receiving surface of the CCD 9 by d. . FIG. 8A shows a state in which the focus detection diaphragm 3 is inserted on the optical path of the photographing lens and the left pupil 3a is opened, and the light beam 27a passing through the left pupil 3a is moved from the optical axis 26 on the light receiving surface of the CCD 9 by + δ / An image is formed at a position separated by two. FIG.
b shows a state in which the right pupil 3b is opened, and the light beam 27b passing through the right pupil 3b is-
An image is formed at a position separated by δ / 2. As described above, in the front focus state, the phase difference between two images composed of light beams passing through two different pupils 3a and 3b is (+ δ / 2) − (− δ /
2) = δ.

FIG. 9 shows a state in which the defocus amount is in the back focus state by d. In the photographing state shown in FIG. 9C, the light beam 27 transmitted through the photographing lens 1 is focused by d behind the light receiving surface of the CCD 9. . FIG. 9A shows a state in which the focus detection diaphragm 3 is inserted on the optical path of the photographing lens and the left pupil 3a is opened, and the light beam 27a passing through the left pupil 3a is -δ from the optical axis 26 on the light receiving surface of the CCD 9. An image is formed at a position separated by / 2. FIG.
b shows a state in which the right pupil 3b is opened, and the light flux 27b passing through the right pupil 3b is shifted from the optical axis 26 on the light receiving surface of the CCD 9 by +
An image is formed at a position separated by δ / 2. As described above, in the front focus state, the phase difference between two images composed of light beams passing through two different pupils 3a and 3b is (−δ / 2) − (+ δ /
2) = − δ.

Thus, the left pupil 3a and the right pupil 3b
The focus state can be detected by calculating the phase difference between the signals for detecting the phase difference between the two images composed of the luminous fluxes that have passed.

The algorithm for calculating the phase difference will be described below. First, for simplicity of explanation, a case where the relative position between the subject and the photographing optical system has not moved will be described as an example.

The phase difference between the phase difference detection signal (left image) consisting of the light beam passing through the left pupil region and the phase difference detection signal (right image) consisting of the light beam passing through the right pupil region is calculated by a correlation operation. Ask. Now, as shown in FIG. 10, the phase difference detection signal is composed of M (horizontal) × N (vertical) signals, and m × n signals are cut out of these signals to perform a correlation operation. As shown in the following formula (1), the correlation is obtained by fixing the cutout position of the left image: a, and changing the positions of a and b while shifting the phase (τx, τy) with respect to the left image sequentially with respect to the left image. Integral value C (τ
x, τy) [τx, τy are integer variables], and a value C (τx, τy) obtained for each phase (τx, τy) is calculated as follows:
The correlation between the two images is used.

[0069]

(Equation 1)

(However, τx = −Tx,..., −2, −1,
.., Tx τy = −Ty,..., −2, −1, 0, 1, 2,.
y)

The correlation amount C (τx, τy) takes the minimum value, and the phase (τx, τy) at this time corresponds to the phase difference (δx, δy) between the data a of the left image and the data b of the right image. I do. Further, the detection accuracy of the phase difference is improved (phase (τx, τ
y) is not an integer value (the signal pitch of the phase difference detection signal is the same as the pixel pitch of the CCD as shown in FIG. 6), but the minimum value of the correlation amount and its value The phase difference may be calculated by interpolation calculation using the values before and after.

If the relative position between the subject and the photographing optical system has not moved, δ
y becomes zero in principle.

To reduce the effects of the pattern of the subject, the contrast, and the like, the effects of the difference in photographing conditions, the effects of the color filter array built in the solid-state image sensor, and the effects of noise, the filter for the phase difference detection signal is used. After performing the processing, a correlation operation may be performed.

Since the relationship between the phase difference and the amount of movement of the image plane and the amount of defocus is determined by the optical system, the amount of defocus is determined from the phase difference, and the amount of extension necessary for focusing is determined. Is performed, and focus is achieved.

Up to this point, a method has been described in which focus detection is performed using two images composed of light beams that have passed through different pupil regions when there is no relative movement between the subject and the optical system.

An algorithm for calculating the phase difference when the object and the optical system move relative to each other will be described below. Although the phase difference can be obtained from two images (left image and right image) composed of light beams in different pupil regions, in the present embodiment,
The left image and the right image are captured in time series, and if there is a relative movement (such as camera shake or movement of the subject) between the subject and the optical system, a focus detection error is included due to the influence.

Therefore, as described above, the readout of the focus detection image data does not involve reading out the entire screen of the CCD as in the case of reading out the image for photographing, but only a part of the image necessary for focus detection. Reading is performed at a higher speed than in the case of normal main photographing, and the image capture interval is devised as short as possible. However, the operation of taking in the signals of the left image and the right image is temporally different, and if there is a relative movement between the camera and the subject during this time, it is inevitable that an error occurs in the phase difference detection.

Therefore, in this embodiment, as described above, the left image 1, the right image 2, the left image 3, the right image 4, the left image 5, and the five images in time series are used as the phase difference detection signals. And correcting a detection error due to relative movement between the camera and the subject (such as camera shake or subject movement) using a plurality of phase differences obtained from each image.

When the camera and the subject move relatively, the effect appears in the phase difference (δx, δy) between the two images. Here, δy is the phase difference in the vertical direction of the image and is a direction perpendicular to the phase shift direction generated in accordance with the optical defocus amount, so that the phase shift component due to defocus is not included, and the relative position between the camera and the subject is not included. There is only a phase shift component due to movement. Therefore, the value of δy is used as it is as the correction amount of the vertical image movement due to the relative movement between the camera and the subject.

Since δx is the phase difference in the horizontal direction of the image and corresponds to the phase shift direction generated according to the optical defocus amount, the value δx obtained from the two images including the relative movement of the camera and the subject includes: A phase shift component due to defocus and a phase shift component due to relative movement between the camera and the subject are included.

FIG. 11 shows the position of the image in the horizontal direction (x direction) due to the relative movement between the camera and the subject after correcting the image movement due to the relative movement of the camera and the subject in the vertical direction, and the phase difference between the images. The relationship is shown. Solid lines L1, R2,
L3, R4, and L5 are time-sequentially switched pupils in order to perform phase difference detection.
A left image 3, a right image 4, and a left image 5, where t = t1, t
Reference numerals 2, t3, t4, and t5 are capture times of the respective images, and the capture time intervals of the respective images are equal. Dashed line R
l ', L2', R3 ', L4', R5 'are L
1, R2, L3, R4, and L5 indicate the position of an image composed of luminous fluxes that have passed through different pupils when the capturing is performed at the same time. Actually, capturing can be performed. No signal.

M 1, m 2, m 3, and m 4 are the amounts of movement of the camera and the subject on the image due to the relative motion of each image capturing time, and δ is a phase shift component due to defocus of the optical system. This is the phase difference to be obtained as focus detection.

First, images L1 and R2 composed of different pupils
The respective phase differences δ1, δ2, δ3, δ4 of R2 and L3, L3 and R4, and R4 and L5 are determined based on the left image.
As can be seen from FIG. 11, each phase difference obtained here includes a phase shift component due to defocus and a phase shift component due to relative movement between the camera and the subject. FIG.
FIG. 9 is a diagram for explaining a method of correcting a phase difference detection error, in which a horizontal axis represents a time axis t, and a vertical axis represents a position x of a subject image in a horizontal direction.
It is. Ll, R2, L3, R4, and L5 are the positions of the subject image captured in time series.
By approximating the movement of the subject image due to the relative motion between the camera and the subject by a quadratic function, the positions of the subject positions L2 ′ and L4 ′ of the left image at times t2 and t4 are obtained. Then, the average value of the phase difference δ2 ′ between L2 ′ and R2 and the phase difference δ4 ′ between L4 and R4 ′ are defined as the finally obtained phase difference δ.

(T1, x1), (t3, x3), (t
5, x5), the quadratic function y = At ² + Bt is calculated as t1 =
0, x1 = 0, and the finally obtained phase difference δ is δ
When obtained from the average value of 2 ′ and δ4 ′, since the capture intervals of the respective images are now equal, the corrected phase difference δ is represented by the following equation (2). δ = (δ1 + 3 × δ2 + 3 × δ3 + δ4) / 8 (2)

From the phase difference δ obtained by correcting the relative movement between the camera and the subject, the amount of extension necessary for focusing is obtained, focus control of the optical system is performed, and the image is taken after focusing. .

Next, the normal mode (non-macro mode) and the macro mode will be described. The non-macro mode is a mode used during normal photographing, and is used, for example, when photographing an object whose distance from the imaging surface to the subject ranges from infinity to 40 cm (closest end). The macro mode is a mode in which an even closer subject can be photographed, for example, a mode in which the subject can be photographed in a range from infinity to a close distance of 20 cm. Selection of this mode corresponds to selection of a subject distance range in which focus detection is possible, and operation of the camera is performed by pressing a macro mode button of an operation switch 24 in FIG.
In non-macro mode, press this switch to enter macro mode, and in macro mode, press this button to enter non-macro mode.

In the macro mode, the subject distance at which the focus can be detected is wider than in the non-macro mode, so that the maximum defocus amount is larger. As an example, in the non-macro mode, when the lens is at the infinity position, the defocus amount for the object at the closest end of 40 cm is the maximum defocus amount. When the distance is in the range, the defocus amount for the object at the closest end of 20 cm becomes the maximum defocus amount,
It is three times that in the non-macro mode. Accordingly, the phase difference in the macro mode becomes larger than in the non-macro mode.

Therefore, the phase differences δ1, δ2, δ3, δ4
In the correlation operation performed when calculating the phase difference, the search range of the image signal at the time of detecting the phase difference (from -Tx to Tx in equation (1), -Tx
If the calculation of y to Ty) is performed using the value in the non-macro mode at the time of setting the macro mode, the phase difference is not obtained and the focus detection becomes impossible. Conversely, in the non-macro mode, if the calculation is performed in the search range of the image signal at the time of detecting the phase difference used in the macro mode, since the maximum defocus amount is 1/3, extra calculation is required. Become. Therefore, in the non-macro mode, the correlation calculation is performed in a search range corresponding to the maximum defocus amount in the mode, and in the macro mode, the correlation calculation is performed by expanding the search range.

After focusing has been performed in this manner, the focus detection diaphragm 3 is retracted from the optical path of the photographing lens, and photographing is performed. Then, the data of the CCD 9 is read for recording, subjected to image signal processing by the digital signal processing unit 12, subjected to processing such as image data compression if necessary, and recorded on a recording medium via the card slot 13.

At this time, the image data is subjected to video processing for finder display in the digital signal processing section 12 and displayed on the EVF 18 via the VRAM 21. This allows the photographer to check the subject image.

In the non-macro mode and the macro mode, since the distance measurement range used for focus detection changes, the size of the AF distance measurement frame displayed on the EVF 18 is changed as shown in FIGS.
Change as shown in (b). FIG. 13A shows an AF ranging frame in the non-macro mode. The width is a size corresponding to m + 2 × Tx, and FIG.
F indicates the distance measurement frame, and the width is m + 2 × Tx ′ (however,
(Tx '> Tx), and the display is enlarged by an amount corresponding to the expanded search range.

Here, a case has been described in which the macro mode is a non-macro mode, and in addition to the range of the subject distance that can be photographed, the macro mode can be photographed to the nearest side, but the macro mode does not include the range of the non-macro mode. For example, 40c
The mode may be such that only the range from m to 20 cm is a range in which focus detection is possible.

(Second Embodiment) In the second embodiment, the number of steps for shifting the image signal in the correlation calculation for obtaining the phase difference is changed depending on the setting conditions of the photographing.

Hereinafter, only different points from the first embodiment will be described, and description of the same portions as the first embodiment will be omitted.

In the case of a camera system which falls within a predetermined allowable defocus amount in the first focus detection and the focus control of the optical system, the second focus detection for confirmation is not performed (close-out focusing), and photographing is performed. You may enter the operation.

However, usually, focus detection is performed for the second and subsequent times to confirm the focus. As described above, in order to perform focusing, it is necessary to perform focus detection and focus control of the optical system two or more times. In the case of a large defocus state, focus detection is first performed in a large defocus state, and finally, Focus detection is performed in a state near the focus. In particular, in the macro mode, an object on the close side is often photographed, and in macro photography, the defocus amount is often increased by a small change in distance as compared with a normal object distance.
As described in the first embodiment, since the search range of the image signal at the time of detecting the phase difference is large, the amount of calculation is larger than that in the non-macro mode. For this reason, first, the focus may be roughly detected, the lens may be moved to the vicinity of the in-focus state, and then the focus may be adjusted with high accuracy.

Therefore, in the first focus detection in the macro mode, the way of shifting τx is expressed by τx = −Tx ′, −Tx ′ + 2.
.., Tx′−2, Tx ′, the step amount for shifting the image signal is doubled. Then, when the previous phase difference δ becomes smaller than the predetermined value, the number of steps for shifting the image signal is changed so as to be shifted by one, and the correlation calculation is performed. That is, at first, the focus detection accuracy is lowered so that the focus is roughly adjusted, and the focus detection accuracy is accurately detected when the focus comes near the focus. As described above, the amount of calculation is reduced and the correlation calculation time is shortened by the step amount being made rough. In addition, also about τy,
Similar actions may be taken.

(Third Embodiment) In a third embodiment, the size of the area of the phase difference detection signal used for the correlation operation in the zoom state (focal length of the optical system) or in the non-macro / macro mode is determined. It is to change.

Hereinafter, only the points different from the first embodiment will be described, and the description of the same parts as the first embodiment will be omitted.

Normally, the size of the area of the phase difference detection signal used for the correlation calculation is fixed to a predetermined size.
The focal length of the optical system and the image magnification of the subject differ between the non-macro mode and the macro mode. In the focus detection method using the phase difference detection method, it is important that an edge of a subject exists in a detection area for detecting a phase difference. But,
In macro photography in the telephoto end with respect to the wide end of the zoom lens and in the macro mode with respect to the non-macro mode, the image magnification is enlarged when compared with the same subject, so that the probability that the edge of the subject enters the detection area decreases. Therefore, at the telephoto end or in the macro mode, which is a shooting condition in which the image magnification is increased, if the area is widened, the edge of the subject enters the area, and the detection accuracy is improved.

As described above, when the image magnification is high, the area for detecting the phase difference used for the correlation calculation is enlarged, so that the focus detection is uselessly repeated in a state where the edge of the subject is not included in the area. Can be prevented, and the number of times of focus detection can be reduced, so that the calculation time can be shortened. As a result, it takes less time to focus,
The operability of the camera is also improved. In addition, expanding the area is
This may be performed not only in the horizontal direction but also in the vertical direction.

(Fourth Embodiment) In the fourth embodiment, whether or not to perform a shift operation in a direction substantially perpendicular to a phase shift direction generated according to the defocus amount of the optical system in the correlation operation. Is selected.

Hereinafter, only different points from the first embodiment will be described, and the description of the same parts as the first embodiment will be omitted.

When the focus detection device of this embodiment captures an optical image composed of light beams having different pupil regions, the capture time differs between the left image and the right image. Therefore, as described above, a countermeasure is taken when there is a relative movement between the subject and the optical system.However, when the camera shake is large, the correlation calculation is performed in the direction of the phase shift generated according to the defocus amount of the optical system. If the shift operation in the vertical direction, which is a direction substantially perpendicular to the vertical direction, is performed, the phase differences δ1, δ2, δ3, δ4, and δ5 will fluctuate, and the detection accuracy of the phase difference δ will deteriorate.

If the S / N of the phase difference detection signal is poor, for example, the subject is dark and the light quantity is
Even when the gain from the CCD is greatly increased by the above, if the vertical shift operation, which is a direction substantially perpendicular to the phase shift direction generated according to the defocus amount of the optical system, is performed by the correlation operation, Rather, the phase differences δ1, δ2, δ
3, δ4 and δ5 vary, and the detection accuracy of the phase difference δ deteriorates.

In macro photography, the above is more likely to occur than in general photography. Further, in the macro mode, the maximum defocus amount is large, and when the defocus amount is large, a low contrast state is obtained.

For this reason, in the macro mode in which this is likely to occur, when performing the correlation calculation, the vertical shift which is a direction substantially perpendicular to the phase shift direction generated according to the defocus amount of the optical system. Do not perform calculations.

As described above, by not performing the shift operation in the vertical direction which is a direction substantially perpendicular to the phase shift direction generated according to the defocus amount of the optical system, it is possible to prevent the detection accuracy from being lowered, and to reduce the calculation time. Is also shorter.

(Fifth Embodiment) In the fifth embodiment, in the correlation operation for obtaining the phase difference, the correlation operation can be performed by thinning out the data of the phase difference detection signal in the region used for the correlation operation. In the macro mode, whether or not to perform the thinning is changed.

Hereinafter, only the points different from the first embodiment will be described, and the description of the same parts as the first embodiment will be omitted.

As described in the first embodiment, when performing the correlation calculation for obtaining the phase difference, the region used for the correlation calculation (FIG. 1)
The data of all the phase difference detection signals within 0 m × n areas) is used as it is. At this time, the signal pitch of the phase difference detection signal is the same as the pixel pitch of the CCD as described above.

However, when it is necessary to perform focus detection and focus control of the optical system twice or more in order to focus,
In the large defocus state, focus detection is first performed in a large defocus state, and finally focus detection is performed in a state near focus. That is, at first, the lens may be roughly moved to the vicinity of the in-focus state, and thereafter, the focus may be accurately adjusted.

In the macro mode, the image magnification is often high, and the search range of the image signal at the time of detecting the phase difference is larger than that in the non-macro mode. Therefore, it is necessary to reduce the correlation calculation amount.

Therefore, at the time of the first focus detection in the macro mode, the data in the horizontal direction corresponding to the phase shift direction generated according to the defocus amount of the optical system is shown in FIG.
As shown in FIG. 4, the data of m × n areas used for the correlation operation is thinned out every other pixel, and the signal pitch of the phase difference detection signal used for the correlation operation is set to の of the pixel pitch of the CCD. Perform correlation calculation. The hatched portion is the data used for the correlation operation. And the previous focus detection result,
When the phase difference δ becomes smaller than a predetermined value, the correlation calculation is performed without performing the thinning.

That is, at first, the focus detection accuracy is changed so that the focus detection accuracy is lowered, the focus is roughly adjusted, and the detection is performed with high accuracy when the focus comes near the focus. In this way, by thinning out, the number of data used for the correlation operation becomes m / 2 × n, and the time required for the correlation operation is shortened.

In this embodiment, the thinning amount is set to 1 /
Although 2, the thinning amount may be changed depending on the focus result. In the vertical direction, thinning may be performed in the same manner.

The processing shown in the focus detection method of the above-described embodiment is mainly performed by the CPU.
The processing is performed based on each function means configured by the program stored in the program ROM.

The above program is not necessarily stored in the ROM, but can be realized, for example, in a form stored in an external memory card. That is, a storage medium storing program codes of software for realizing the functions of the above-described embodiments is supplied to a system or an apparatus, and an information processing apparatus (or CPU) of the system or apparatus stores the program stored in the storage medium. Needless to say, this can also be achieved by reading and executing the code.

In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

As a storage medium for supplying the program code, for example, a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, C
DR, magnetic tape, nonvolatile memory card, RO
M, DVD, etc. can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the basic program running on the information processing apparatus based on the instruction of the program code. It goes without saying that software (OS) or the like performs a part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.

Further, after the program code read from the storage medium is written to a memory provided in a function expansion board inserted into the information processing device or a function expansion unit connected to the information processing device, the program code of the program code is read out. It goes without saying that the CPU or the like provided in the function expansion board or the function expansion unit performs part or all of the actual processing based on the instruction, and the processing realizes the functions of the above-described embodiments. .

According to the present embodiment described above, when the calculation for obtaining the phase difference for focus detection is performed, the calculation method can be changed as follows. 1. The focus detection calculation method is changed based on the photographing setting conditions. 2. In the correlation calculation for obtaining the phase difference from the phase difference detection signal, the search range of the image signal at the time of detecting the phase difference is changed according to the setting conditions of the photographing. 3. In the correlation calculation for obtaining the phase difference from the phase difference detection signal, the step amount for shifting the image signal at the time of detecting the phase difference is changed according to the setting condition of the photographing. 4. In the correlation calculation for obtaining the phase difference from the phase difference detection signal, the size of the area of the phase difference signal used for the correlation calculation is changed according to the setting conditions of the imaging. 5. In the correlation calculation for obtaining the phase difference from the phase difference detection signal, it is changed whether or not to perform the shift calculation in a direction substantially perpendicular to the phase shift direction generated according to the defocus amount of the optical system. 6. In the correlation operation for obtaining the phase difference, the image processing apparatus includes a thinning unit that can perform the correlation operation by thinning out the data of the phase difference detection signal in the area used for the correlation operation. Change. 7. The photographing setting condition is set to a range of a subject distance in which focus detection is possible, and the calculation method is changed according to the setting condition. 8. The photographing setting condition is the focal length of the optical system, and the calculation method is changed according to the setting condition. Therefore, it is possible to use a focus detection calculation method suitable for the setting conditions at the time of shooting, and it is possible to prevent focus detection from being disabled. Therefore, compared with the case where one focus detection calculation method is used in all cases, unnecessary calculation can be omitted, and the calculation time can be shortened.

[0124]

According to the present invention, it is possible to prevent the focus detection from being disabled by using a focus detection calculation method suitable for the setting conditions of the camera, and to shorten the focus detection calculation time. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a focus detection device according to an embodiment of the present invention and an imaging device using the same.

FIG. 2 is a schematic diagram illustrating a positional relationship between a focus detection diaphragm and a light shielding plate according to an embodiment of the present invention.

FIG. 3 shows an interline type C according to an embodiment of the present invention.
FIG. 3 is a plan view showing a configuration of a CD.

FIG. 4 is a schematic diagram showing an imaging area of a CCD according to an embodiment of the present invention.

FIG. 5 is a schematic diagram showing a timing chart for one vertical period when a vertical charge transfer element of a CCD according to an embodiment of the present invention is driven by four phases.

FIG. 6 is a schematic diagram illustrating a calculation process when obtaining a phase difference detection signal according to an embodiment of the present invention.

FIG. 7 is a schematic diagram illustrating a focus detection principle according to an embodiment of the present invention.

FIG. 8 is a schematic diagram illustrating a focus detection principle according to an embodiment of the present invention.

FIG. 9 is a schematic diagram illustrating a focus detection principle according to an embodiment of the present invention.

FIG. 10 is a schematic diagram showing a method for obtaining a correlation when a phase difference is obtained by a correlation operation according to an embodiment of the present invention.

FIG. 11 is a schematic diagram illustrating a relationship between a horizontal position of an image due to a relative movement of an imaging device and a subject and a phase difference between the images according to an embodiment of the present invention.

FIG. 12 is a schematic diagram illustrating a method for correcting a phase difference detection error according to an embodiment of the present invention.

FIG. 13 is a schematic diagram illustrating an EVF AF ranging frame in a non-macro mode and a macro mode according to an embodiment of the present invention.

FIG. 14 is a schematic diagram illustrating a method for thinning out data used for correlation calculation according to an embodiment of the present invention.

FIG. 15 is a schematic sectional view showing a single-lens reflex camera having a conventional phase difference detection type focus detection device.

FIG. 16 is a schematic diagram illustrating the principle of focus detection of a conventional focus detection device.

FIG. 17 is a schematic diagram illustrating the principle of focus detection of a conventional focus detection device.

[Explanation of symbols]

1a Focusing lens group of photographing lens 1b Lens group other than focusing lens group of photographing lens 2 Lens extension mechanism 3 Focus detection aperture 4 Motor 5 Shield plate 6 Motor 7 Optical low-pass filter 8 Infrared cut filter 9 CCD 10 Amplifier 11 A / D converter 12 Digital signal processing unit 13 System control unit 14 CCD driver 15 Lens control unit 16 Buffer memory 17 Card slot and its control unit 18 Electronic viewfinder (EVF) 19 LCD driver 20 D / A converter 21 VRAM 22 External black and white liquid crystal (LCD) 23 LCD driver 24 Operation switch

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H011 AA03 BA22 BB01 BB02 BB04 CA01 CA21 DA06 2H051 AA00 BA07 BA12 CB05 CB06 CB22 CE18 CE21 CE23 CE26 DA04 DA18 EA08 EB13 FA61 FA63

Claims (23)

[Claims] 1. A focus detection method for forming a light beam having passed through at least two different pupil regions of an imaging optical system on an image sensor, and obtaining a phase difference between at least two output images obtained from the image sensor. A focus detection method, wherein the calculation method of the focus detection is changed according to a setting condition of photographing. 2. The focus detection method according to claim 1, wherein at least two subject distance ranges can be set, and the photographing setting condition is the subject distance range setting. 3. The focus detection method according to claim 2, wherein one of the ranges of the subject distance is set wider on the closest side than the range of the other subject distances. 4. The focus detection method according to claim 1, wherein the setting condition of the photographing is a focal length of the optical system for photographing. 5. The search range of the output image along the optical axis direction of the optical system when the output image is detected is changed according to a setting condition of the photographing.
The focus detection method according to any one of the above items. 6. The focus detection according to claim 1, wherein a step amount of a signal of the output image at the time of detecting the output image is changed according to a setting condition of the photographing. Method. 7. The focus detection method according to claim 1, wherein a size of an area of the output image on the image sensor is changed according to a setting condition of the photographing. . 8. The apparatus according to claim 1, wherein whether to perform a shift operation in a direction perpendicular to a defocus direction of the optical system is changed according to a setting condition of the photographing. 3. The focus detection method according to item 1. 9. The focus detection method according to claim 1, wherein the data of the output image is thinned according to a setting condition of the photographing. 10. The focus detection method according to claim 1, wherein the light flux is formed on the image sensor in a time-series manner. 11. A focus detection device that forms a light beam having passed through at least two different pupil regions of an imaging optical system on an image sensor and obtains a phase difference between at least two output images obtained from the image sensor. A focus detection device, wherein a calculation method of the focus detection is changed according to a setting condition of photographing. 12. An image forming means for forming an image of a light beam having passed through at least two different pupil regions of an imaging optical system on an image sensor, and obtaining a phase difference between at least two output images obtained from the image sensor. The focus detection device according to claim 11, further comprising: a detection unit; and a calculation unit that changes a calculation method of the focus detection according to a setting condition of photographing. 13. The focus detection apparatus according to claim 12, wherein at least two subject distance ranges can be set, and the photographing setting condition is the subject distance range setting. 14. The focal point according to claim 11, wherein one of the object distance ranges is set wider on the closest side than the other object distance ranges. Detection device. 15. The focus detection device according to claim 11, wherein the setting condition of the photographing is a focal length of the optical system for photographing. 16. A search range of the output image along the optical axis direction of the optical system when the output image is detected according to a setting condition of the photographing. The focus detection device according to any one of claims 15 to 15. 17. The apparatus according to claim 11, wherein a step amount of a signal of the output image at the time of detecting the output image is changed according to a setting condition of the photographing. Focus detection device. 18. The apparatus according to claim 11, wherein a size of an area of the output image on the image sensor is changed according to a setting condition of the photographing. Focus detection device. 19. The apparatus according to claim 1, wherein whether to perform a shift operation in a direction perpendicular to a defocus direction of the optical system is changed according to a setting condition of the photographing.
The focus detection device according to any one of claims 1 to 18. 20. The method according to claim 11, wherein the data of the output image is thinned according to a setting condition of the photographing.
10. The focus detection device according to claim 9. 21. The image forming apparatus according to claim 11, wherein said light beam is formed on said image pickup element in a time-series manner.
21. The focus detection device according to any one of 20. 22. The imaging means divides a photographing light beam of the photographing optical system into at least two regions in a time-series manner, and comprises a light beam passing through different pupil regions of the photographing optical system. The pupil position moving means for projecting an image on the image pickup device is further provided.
22. The focus detection device according to any one of 21. 23. A computer-readable storage medium storing a program for causing a computer to execute the procedure of the focus detection method according to claim 1. Description: