JP2015145970A - Imaging apparatus, control method therefor, program, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device that assists a user so as to be able to smoothly focus on an in-focus position without being confused with a manual operation.SOLUTION: An imaging device moving a lens to focus on a subject and photographing an image of a subject comprises: a plurality of focus detection units that respectively detects an in-focus state of the lens by each different method; a switch unit that switches the plurality of focus detection parts in accordance with the in-focus state of the lens; a display unit that displays an amount of defocus of the lens detected by the plurality of focus detection units; and an adjustment unit that adjusts a value to be displayed by the display unit so that, when the plurality of focus detection units is switched by the switch unit, a value of the amount of defocus of the lens used before switched and detected by the focus detection units and a value of the amount of defocus of the lens to be used after switched and to be detected by the focus detection units are continuously linked.

Description

  The present invention relates to an assist technique for focusing with manual focus in an imaging apparatus.

  When shooting a still image, it is common to use a widely known autofocus (hereinafter referred to as AF) function to adjust the focus. However, when shooting a moving image, all the behaviors when focusing are recorded as a part of the moving image, so focus adjustment may be performed by manual focus (hereinafter referred to as MF) without using AF.

  By performing the focus adjustment with the MF in this manner, it is possible to shoot a video that focuses at an arbitrary place at an arbitrary speed. However, in MF, the user needs to determine where the in-focus position is when focusing, but it may be difficult to confirm on the display on the back of the camera or the like. In order to solve such problems, techniques for assisting in MF are proposed in Patent Document 1, Patent Document 2, and the like.

JP 2007-279334 A JP 2011-19110 A

  In the prior art disclosed in the above-mentioned patent document, when the focus ring is turned to approach the in-focus state, the indicator displays the remaining amount until the in-focus state is achieved. However, at this time, when the focus ring is turned to approach the in-focus state, the focus detection is performed again at a predetermined timing, so that the focus detection result changes each time, and the amount until the in-focus state indicated by the indicator changes. . Therefore, there is a problem that it is difficult to understand how much the user needs to turn the focus ring.

  Furthermore, in a camera that performs focus detection by combining a plurality of focus detection methods, there is a problem that when the focus detection method is switched, the focus detection result changes and the indicator display becomes unstable.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an imaging device that assists the user so that the user can smoothly focus on the in-focus position without hesitation in manual operation. is there.

  An imaging apparatus according to the present invention is an imaging apparatus that drives a lens to focus on a subject and captures an image of the subject, and includes a plurality of focus detection units that detect the focusing state of the lens by different methods. Switching means for switching the plurality of focus detection means according to the in-focus state of the lens, display means for displaying the defocus amount of the lens detected by the plurality of focus detection means, and the plurality of the plurality of focus detection means When the focus detection unit is switched by the switching unit, the display of the defocus amount of the lens detected by the focus detection unit used before switching and the focus detection unit used after switching are detected. Adjusting means for adjusting a value displayed by the display means so that the display of the defocus amount of the lens is continuously connected. And butterflies.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the imaging device which assists so that a user can focus to a focus position smoothly, without being lost by manual operation.

1 is a schematic configuration diagram of an imaging apparatus according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of a pixel arrangement in the first embodiment. FIG. 2 is a schematic plan view and a schematic cross-sectional view of a pixel according to the first embodiment. Schematic explanatory drawing of the pixel and pupil division in a 1st embodiment. Schematic explanatory drawing of the image sensor and pupil division in a 1st embodiment. FIG. 5 is a schematic relationship diagram between a defocus amount and an image shift amount of a first focus detection signal and a second focus detection signal in the first embodiment. Schematic of the flow of the 1st focus detection process in 1st Embodiment. Schematic explanatory drawing of the shading by the pupil shift of the 1st focus detection signal and the 2nd focus detection signal in a 1st embodiment. The figure which shows the example of the filter frequency band in 1st Embodiment. The figure which shows the example of the 1st focus detection signal and 2nd focus detection signal in 1st Embodiment. The figure which shows the example of the 1st focus detection signal and the 2nd focus detection signal after the optical correction process and 1st filter process in 1st Embodiment. FIG. 5 is a diagram illustrating a calculation example of a first detection defocus amount and a second detection defocus amount according to the first embodiment. FIG. 3 is a schematic explanatory diagram of a refocus process in the first embodiment. Schematic of the flow of the 2nd focus detection process in 1st Embodiment. The figure which shows the example of the 1st focus detection signal and the 2nd focus detection signal after the 2nd filter process in 1st Embodiment. The figure which shows the example which carried out the shift addition of the 1st focus detection signal and 2nd focus detection signal after the 2nd filter process in 1st Embodiment. The figure which shows the example of the 2nd evaluation value in 1st Embodiment. FIG. 3 is a schematic explanatory diagram of a refocusable range in the first embodiment. Schematic of the flow of the focus detection process in 1st Embodiment. FIG. 6 is a diagram illustrating an example of AF frame display according to the first embodiment. The figure which shows the relationship of the rotation direction of the indicator and focus ring in 1st Embodiment. The figure which shows the relationship between the indicator scale and defocus amount in 1st Embodiment. FIG. 10 is a diagram illustrating calibration values according to a subject and shooting conditions in the second embodiment. FIG. 10 is a diagram illustrating calibration values according to a subject and shooting conditions in the second embodiment.

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

(First embodiment)
This embodiment uses a plurality of focus detection methods for displaying an indicator for assisting focus adjustment during MF (manual focus). Hereinafter, a first focus detection method and a second focus detection method using the imaging surface phase difference method used in the present embodiment will be described.

[overall structure]
FIG. 1 shows a configuration diagram of a camera which is an image pickup apparatus having an image pickup element in the present embodiment. In FIG. 1, reference numeral 101 denotes a first lens group disposed at the tip of the imaging optical system, which is held so as to be able to advance and retract in the optical axis direction. Reference numeral 102 denotes an aperture / shutter, which adjusts the light amount at the time of shooting by adjusting the aperture diameter, and also functions as an exposure time adjustment shutter at the time of still image shooting. Reference numeral 103 denotes a second lens group. The diaphragm shutter 102 and the second lens group 103 integrally move forward and backward in the optical axis direction, and perform a zooming function (zoom function) in conjunction with the forward and backward movement of the first lens group 101.

  Reference numeral 105 denotes a third lens group that performs focus adjustment by advancing and retreating in the optical axis direction. Reference numeral 106 denotes an optical low-pass filter, which is an optical element for reducing false colors and moire in a captured image. Reference numeral 107 denotes an image pickup element including a two-dimensional CMOS photosensor and a peripheral circuit, which is disposed on the image forming plane of the image forming optical system.

  A zoom actuator 111 rotates a cam cylinder (not shown) to drive the first lens group 111 to the third lens group 105 forward and backward in the optical axis direction, thereby performing a zooming operation. Reference numeral 112 denotes an aperture shutter actuator that controls the aperture diameter of the aperture / shutter 102 to adjust the amount of photographing light, and controls the exposure time during still image photographing. Reference numeral 114 denotes a focus actuator, which performs focus adjustment by driving the third lens group 105 back and forth in the optical axis direction.

  Reference numeral 115 denotes an electronic flash for illuminating a subject at the time of photographing, and a flash illumination device using a xenon tube is suitable, but an illumination device including an LED that emits light continuously may be used. Reference numeral 116 denotes an AF auxiliary light device that projects an image of a mask having a predetermined aperture pattern onto a subject field via a light projection lens, thereby improving the focus detection capability for a dark subject or a low-contrast subject.

  Reference numeral 121 denotes an in-camera CPU that controls various controls of the camera body, and includes a calculation unit, ROM, RAM, A / D converter, D / A converter, communication interface circuit, and the like. Then, based on a predetermined program stored in the ROM, various circuits included in the camera are driven, and a series of operations such as AF, photographing, image processing, and recording are executed.

  An electronic flash control circuit 122 controls lighting of the electronic flash 115 in synchronization with the photographing operation. Reference numeral 123 denotes an auxiliary light driving circuit that controls the lighting of the AF auxiliary light device 116 in synchronization with the focus detection operation. An image sensor driving circuit 124 controls the image capturing operation of the image sensor 107 and A / D converts the acquired image signal and transmits the image signal to the CPU 121. An image processing circuit 125 performs processes such as γ conversion, color interpolation, and JPEG compression of the image acquired by the image sensor 107.

  A focus driving circuit 126 controls the focus actuator 114 based on the focus detection result, and performs focus adjustment by driving the third lens group 105 back and forth in the optical axis direction. Reference numeral 128 denotes an aperture shutter drive circuit which controls the aperture shutter actuator 112 to control the aperture of the aperture / shutter 102. Reference numeral 129 denotes a zoom drive circuit that drives the zoom actuator 111 in accordance with the zoom operation of the photographer.

  Reference numeral 131 denotes a display device such as an LCD, which displays information related to the shooting mode of the camera, a preview image before shooting and a confirmation image after shooting, a focus state display image at the time of focus detection, and the like. An operation switch group 132 includes a power switch, a release (shooting trigger) switch, a zoom operation switch, a shooting mode selection switch, and the like. Reference numeral 133 denotes a detachable flash memory that records a photographed image.

[Image sensor]
FIG. 2 shows a schematic diagram of the arrangement of the imaging pixels and focus detection pixels of the imaging device in the present embodiment. FIG. 2 shows a pixel (imaging pixel) array of the two-dimensional CMOS sensor (imaging device) of this embodiment in a range of 4 columns × 4 rows, and a focus detection pixel array in a range of 8 columns × 4 rows. Is.

  In the present embodiment, the pixel group 200 of 2 columns × 2 rows shown in FIG. 2 includes a pixel 200R having an R (red) spectral sensitivity on the upper left and a pixel 200G having a G (green) spectral sensitivity on the upper right. A pixel 200B having a spectral sensitivity of B (blue) is arranged at the lower left. Further, each pixel includes a first focus detection pixel 201 and a second focus detection pixel 202 arranged in 2 columns × 1 row.

  A large number of 4 columns × 4 rows of pixels (8 columns × 4 rows of focus detection pixels) shown in FIG. 2 are arranged on the surface, and a captured image (focus detection signal) can be acquired. In the present embodiment, the pixel period P is 4 μm, the number of pixels N is 5575 columns × 3725 rows = about 20.75 million pixels, the column direction cycle PAF of focus detection pixels is 2 μm, and the focus detection pixel number NAF is 11150 horizontally. The description will be made assuming that the image sensor has columns × vertical rows 3725 = approximately 41.5 million pixels.

  FIG. 3A shows a plan view of one pixel 200G of the image pickup device shown in FIG. 2 as viewed from the light receiving surface side (+ z side) of the image pickup device, and a cross section taken along the line aa in FIG. A cross-sectional view seen from the y side is shown in FIG.

  As shown in FIG. 3, in the pixel 200G of the present embodiment, a microlens 305 for condensing incident light is formed on the light receiving side of each pixel, and NH division (two divisions) is performed in the x direction and NV is performed in the y direction. A divided (one-divided) photoelectric conversion unit 301 and a photoelectric conversion unit 302 are formed. The photoelectric conversion unit 301 and the photoelectric conversion unit 302 (sub-pixel) correspond to the first focus detection pixel 201 and the second focus detection pixel 202, respectively.

  The photoelectric conversion unit 301 and the photoelectric conversion unit 302 may be a pin structure photodiode in which an intrinsic layer is sandwiched between a p-type layer and an n-type layer, or an intrinsic layer is omitted as necessary, and a pn junction is formed. A photodiode may be used.

  In each pixel, a color filter 306 is formed between the microlens 305 and the photoelectric conversion unit 301 and the photoelectric conversion unit 302. Further, as necessary, the spectral transmittance of the color filter may be changed for each sub-pixel, or the color filter may be omitted.

  The light incident on the pixel 200 </ b> G illustrated in FIG. 3 is collected by the microlens 305, dispersed by the color filter 306, and then received by the photoelectric conversion unit 301 and the photoelectric conversion unit 302.

  In the photoelectric conversion unit 301 and the photoelectric conversion unit 302, a pair of electrons and holes are generated according to the amount of received light and separated by a depletion layer, and then negatively charged electrons are accumulated in an n-type layer (not shown), The holes are discharged to the outside of the image sensor through a p-type layer connected to a constant voltage source (not shown).

  Electrons accumulated in the n-type layer (not shown) of the photoelectric conversion unit 301 and the photoelectric conversion unit 302 are transferred to the capacitance unit (FD) through the transfer gate and converted into a voltage signal.

  FIG. 4 is a schematic explanatory diagram showing the correspondence between the pixel structure of this embodiment shown in FIG. 3 and pupil division. FIG. 4 shows a sectional view of the pixel structure of the present embodiment shown in FIG. 3A as viewed from the + y side and an exit pupil plane of the imaging optical system. In FIG. 4, in order to correspond to the coordinate axis of the exit pupil plane, the x-axis and y-axis of the cross-sectional view are inverted with respect to FIG.

  In FIG. 4, the first pupil partial region 501 of the first focus detection pixel 201 is generally conjugated with the light receiving surface of the photoelectric conversion unit 301 whose center of gravity is decentered in the −x direction and the microlens. , The first focus detection pixel 201 represents a pupil region that can receive light. The first pupil partial region 501 of the first focus detection pixel 201 has an eccentric center of gravity on the + X side on the pupil plane.

  In FIG. 4, the second pupil partial region 502 of the second focus detection pixel 202 is generally conjugated with the light receiving surface of the photoelectric conversion unit 302 whose center of gravity is decentered in the + x direction and the microlens. A pupil region that can be received by the second focus detection pixel 202 is shown. The center of gravity of the second pupil partial region 502 of the second focus detection pixel 202 is eccentric to the −X side on the pupil plane.

  In FIG. 4, the pupil region 500 can receive light in the entire pixel 200 </ b> G when the photoelectric conversion unit 301 and the photoelectric conversion unit 302 (first focus detection pixel 201 and second focus detection pixel 202) are all combined. This is the pupil area.

  FIG. 5 is a schematic diagram showing the correspondence between the image sensor of this embodiment and pupil division. Light beams that have passed through different pupil partial areas of the first pupil partial area 501 and the second pupil partial area 502 are incident on each pixel of the image sensor at different angles, and are used for first focus detection divided into 2 × 1. Light is received by the pixel 201 and the second focus detection pixel 202. In the present embodiment, the pupil region is divided into two pupils in the horizontal direction. If necessary, pupil division may be performed in the vertical direction.

  The imaging device of the present embodiment includes a first focus detection pixel that receives a light beam passing through the first pupil partial region of the imaging optical system, and a second pupil partial region of the imaging optical system different from the first pupil partial region. A plurality of second focus detection pixels for receiving a light beam passing through the first imaging element and a plurality of imaging pixels for receiving a light beam passing through a pupil region including the first pupil partial region and the second pupil partial region of the imaging optical system. ing. In the imaging device of the present embodiment, each imaging pixel is composed of a first focus detection pixel and a second focus detection pixel.

  If necessary, the imaging pixel, the first focus detection pixel, and the second focus detection pixel are configured as separate pixels, and the first focus detection pixel and the second focus detection pixel are included in a part of the imaging pixel array. A configuration in which pixels are partially arranged may be employed.

  In the present embodiment, a first focus signal is generated by collecting the light reception signals of the first focus detection pixels 201 of each pixel of the image sensor, and the second light reception signals of the second focus detection pixels 202 of each pixel are collected. A focus signal is generated to perform focus detection. Further, by adding the signals of the first focus detection pixel 201 and the second focus detection pixel 202 for each pixel of the image pickup device, an image pickup signal (captured image) having a resolution of N effective pixels is generated.

[Relationship between defocus amount and image shift amount]
Hereinafter, the relationship between the defocus amount and the image shift amount of the first focus detection signal and the second focus detection signal acquired by the image sensor of the present embodiment will be described.

  FIG. 6 shows a schematic relationship diagram of the defocus amounts of the first focus detection signal and the second focus detection signal and the image shift amount between the first focus detection signal and the second focus detection signal. The imaging element (not shown) of the present embodiment is disposed on the imaging surface 800, and the exit pupil of the imaging optical system is placed in the first pupil partial region 501 and the second pupil partial region 502, as in FIGS. Divided into two.

  The defocus amount d is a distance | d | from the imaging position of the subject to the imaging surface, and a negative sign (d <0) indicates a front pin state where the imaging position of the subject is on the subject side from the imaging surface. A rear pin state in which the imaging position of the subject is on the opposite side of the subject from the imaging surface is defined as a positive sign (d> 0). An in-focus state where the imaging position of the subject is on the imaging surface (in-focus position) is d = 0. In FIG. 6, the subject 801 shows an example in a focused state (d = 0), and the subject 802 shows an example in a front pin state (d <0). The front pin state (d <0) and the rear pin state (d> 0) are combined to form a defocus state (| d |> 0).

  In the front pin state (d <0), the luminous flux that has passed through the first pupil partial area 501 (second pupil partial area 502) out of the luminous flux from the subject 802 is once condensed and then the gravity center position of the luminous flux. The image spreads in the width Γ1 (Γ2) with G1 (G2) as the center, resulting in a blurred image on the imaging surface 800. The blurred image is received by the first focus detection pixel 201 (second focus detection pixel 202) constituting each pixel arranged in the image sensor, and a first focus detection signal (second focus detection signal) is generated. Is done. Therefore, the first focus detection signal (second focus detection signal) is recorded as a subject image in which the subject 802 is blurred by the width Γ1 (Γ2) at the gravity center position G1 (G2) on the imaging surface 800. The blur width Γ1 (Γ2) of the subject image generally increases in proportion to the amount of defocus amount d | d |. Similarly, the magnitude | p | of the object image displacement amount p (= difference G1-G2 in the center of gravity of the light beam) between the first focus detection signal and the second focus detection signal is also the size of the defocus amount d. As | d | increases, it generally increases in proportion. Even in the rear pin state (d> 0), the image shift direction of the subject image between the first focus detection signal and the second focus detection signal is opposite to that in the front pin state, but the same.

  Therefore, in this embodiment, as the magnitude of the defocus amount of the first focus detection signal and the second focus detection signal or the imaging signal obtained by adding the first focus detection signal and the second focus detection signal increases. The amount of image shift between the first focus detection signal and the second focus detection signal increases.

[Focus detection]
In the present embodiment, using the relationship between the defocus amount and the image shift amount of the first focus detection signal and the second focus detection signal, a method based on the first focus detection of the phase difference method and the refocus principle (hereinafter referred to as “refocus”). Second focus detection). First focus detection is performed to adjust the focus from the large defocus state to the small defocus state, and second focus detection is performed to adjust the focus from the small defocus state to the vicinity of the best focus position.

[First focus detection of phase difference method]
The phase difference type first focus detection in the present embodiment will be described below.

  In the first focus detection based on the phase difference method, the first focus detection signal and the second focus detection signal are relatively shifted to calculate a correlation amount (first evaluation value) representing the degree of coincidence of the signals. The image shift amount is detected from the shift amount that improves the degree of coincidence. As the defocus amount of the image pickup signal increases, the image shift amount is determined based on the relationship that the image shift amount increases between the first focus detection signal and the second focus detection signal. Focus detection is performed by converting into a focus amount.

  FIG. 7 shows a schematic diagram of the flow of the first focus detection process of the present embodiment. Note that the operation of FIG. 7 is executed by the focus detection signal generation unit, the image sensor 107 serving as the first focus detection unit, the image processing circuit 125, and the CPU 121 of the present embodiment.

  In step S110, a focus detection area for performing focus adjustment is set from the effective pixel area of the image sensor. The image sensor 107 generates a first focus detection signal from the light reception signal of the first focus detection pixel in the focus detection area, and generates a second focus detection signal from the light reception signal of the second focus detection pixel in the focus detection area. .

  In step S120, the first focus detection signal and the second focus detection signal are each subjected to 3-pixel addition processing in the column direction for suppressing the signal data amount, and further, the Bayer for converting the RGB signal into the luminance Y signal. (RGB) addition processing is performed. These two addition processes are combined into a first pixel addition process.

  In step S130, shading correction processing (optical correction processing) is performed on the first focus detection signal and the second focus detection signal, respectively.

  Hereinafter, shading due to pupil shift between the first focus detection signal and the second focus detection signal will be described. FIG. 8 shows the first pupil partial region 501 of the first focus detection pixel 201, the second pupil partial region 502 of the second focus detection pixel 202, and the exit pupil 400 of the imaging optical system at the peripheral image height of the image sensor. The relationship is shown.

  FIG. 8A shows a case where the exit pupil distance Dl of the imaging optical system and the set pupil distance Ds of the image sensor are the same. In this case, the exit pupil 400 of the imaging optical system is substantially equally divided by the first pupil partial region 501 and the second pupil partial region 502.

  On the other hand, when the exit pupil distance D1 of the imaging optical system shown in FIG. 8B is shorter than the set pupil distance Ds of the image sensor, the peripheral pupil height of the image sensor is equal to the exit pupil of the imaging optical system. A pupil shift of the entrance pupil of the image sensor occurs, and the exit pupil 400 of the imaging optical system is non-uniformly divided into pupils. Similarly, when the exit pupil distance Dl of the imaging optical system shown in FIG. 8C is longer than the set pupil distance Ds of the image sensor, the exit pupil and the image sensor of the imaging optical system are used at the peripheral image height of the image sensor. This causes a pupil shift of the entrance pupil, and the exit pupil 400 of the imaging optical system is non-uniformly divided into pupils. As pupil division becomes nonuniform at the peripheral image height, the intensity of the first focus detection signal and the second focus detection signal also becomes nonuniform, and one of the first focus detection signal and the second focus detection signal Shading occurs with increasing strength and decreasing the other strength.

  In step S130 of FIG. 7, the first shading correction coefficient of the first focus detection signal and the second focus are determined according to the image height of the focus detection area, the F value of the imaging lens (imaging optical system), and the exit pupil distance. A second shading correction coefficient of the detection signal is generated respectively. The first focus detection signal is multiplied by the first focus detection signal, the second shading correction coefficient is multiplied by the second focus detection signal, and shading correction processing (optical correction processing) of the first focus detection signal and the second focus detection signal is performed. )I do.

  In the first focus detection of the phase difference method, the first detection defocus amount is detected based on the correlation (signal coincidence) between the first focus detection signal and the second focus detection signal. When shading due to pupil shift occurs, the correlation (signal coincidence) between the first focus detection signal and the second focus detection signal may be reduced. Therefore, in the first focus detection of the phase difference method, the shading correction processing (optical) is performed in order to improve the correlation (signal matching degree) between the first focus detection signal and the second focus detection signal and to improve the focus detection performance. It is desirable to perform correction processing.

  In step S140 of FIG. 7, the first filter processing is performed on the first focus detection signal and the second focus detection signal. An example of the pass band of the first filter processing of the present embodiment is shown by a solid line in FIG. In the present embodiment, since the focus detection in the large defocus state is performed by the first focus detection of the phase difference method, the pass band of the first filter processing is configured to include the low frequency band. When the focus adjustment is performed from the large defocus state to the small defocus state as necessary, the pass band of the first filter processing at the time of the first focus detection according to the defocus state is indicated by a one-dot chain line in FIG. In this way, the frequency may be adjusted to a higher frequency band.

  Next, in step S150 of FIG. 7, a first shift process for relatively shifting the first focus detection signal and the second focus detection signal after the first filter process in the pupil division direction is performed, and the degree of coincidence of the signals is expressed. A correlation amount (first evaluation value) is calculated.

  The k-th first focus detection signal after the first filter processing is A (k), the second focus detection signal is B (k), and the range of the number k corresponding to the focus detection area is W. The correlation amount (first evaluation value) COR is calculated by equation (1), where s1 is the shift amount by the first shift process and Γ1 is the shift range of the shift amount s1.

  By the first shift process of the shift amount s1, the k-th first focus detection signal A (k) and the k-s1st second focus detection signal B (k-s1) are subtracted in correspondence to generate a shift subtraction signal. To do. The absolute value of the generated shift subtraction signal is calculated, the number k is summed within the range W corresponding to the focus detection area, and the correlation amount (first evaluation value) COR (s1) is calculated. If necessary, the correlation amount (first evaluation value) calculated for each row may be added over a plurality of rows for each shift amount.

  In step S160, a real-valued shift amount at which the correlation amount is the minimum value is calculated from the correlation amount (first evaluation value) by subpixel calculation, and is set as the image shift amount p1. A first detection defocus amount (Def1) is obtained by multiplying the image shift amount p1 by the image height of the focus detection area, the F value of the imaging lens (imaging optical system), and the first conversion coefficient K1 corresponding to the exit pupil distance. Is detected.

  In the present embodiment, the first focus detection unit of the phase difference method performs the first filter processing and the first shift processing on the first focus detection signal and the second focus detection signal, calculates the correlation amount, and calculates the correlation amount from the correlation amount. A first detection defocus amount is detected.

  In the imaging device of the present embodiment, the light beam received by the focus detection pixels (first focus detection pixel and second focus detection pixel) is different from the light beam received by the imaging pixel, and each aberration of the imaging optical system is different. The influence on the focus detection pixel (spherical aberration, astigmatism, coma, etc.) is different from the influence on the imaging signal. When the aperture value (F value) of the imaging optical system is small (bright), the difference becomes larger. Therefore, when the aperture value (F value) of the imaging optical system is small (bright), the detection focus position (position where the first detection defocus amount is 0) calculated by the first focus detection of the phase difference method is used. There may be a difference between the best focus position of the imaging signal (the MTF peak position of the imaging signal). Therefore, particularly when the aperture value of the imaging optical system is equal to or smaller than the predetermined aperture value, the focus detection accuracy of the phase difference type first focus detection may be lowered.

  FIG. 10 shows an example of the first focus detection signal (broken line) and the second focus detection signal (solid line) at the best focus position of the image pickup signal at the peripheral image height of the image sensor of the present embodiment. Although it is the best focus position of the imaging signal, the signal shapes of the first focus detection signal and the second focus detection signal are different due to the influence of each aberration of the imaging optical system. FIG. 11 shows the first focus detection signal (broken line) and the second focus detection signal (solid line) after the shading correction process and the first filter process. Although it is the best focus position of the imaging signal, the image shift amount p1 between the first focus detection signal and the second focus detection signal is not zero. Therefore, a difference is generated between the detection focus position calculated by the first focus detection of the phase difference method and the best focus position of the imaging signal.

  FIG. 12 shows an example of the first detection defocus amount (broken line) by the first focus detection of the phase difference method in the present embodiment. The horizontal axis is the set defocus amount, and the vertical axis is the detected defocus amount. The first focus detection signal and the second focus detection signal shown in FIG. 10 are the first focus detection signal and the second focus detection signal when the set defocus amount is 0 [mm] in FIG. At the best focus position where the set defocus amount is 0, the first detection defocus amount by the first focus detection is offset by about 50 μm to the rear pin side, and the detection focus calculated by the best focus position and the first focus detection. It can be seen that there is a difference of about 50 μm from the focal position.

  The object of the present embodiment is to suppress the difference between the detected in-focus position calculated from the focus detection signal and the best in-focus position of the imaging signal, thereby enabling highly accurate focus detection. Therefore, in addition to the first focus detection based on the phase difference method, the second focus detection based on the refocus method that enables highly accurate focus detection near the best focus position of the imaging optical system is performed.

[Refocus second focus detection]
Hereinafter, the refocus second focus detection in the present embodiment will be described.

  In the second focus detection of the refocus method of the present embodiment, the first focus detection signal and the second focus detection signal are relatively shifted and added to generate a shift addition signal (refocus signal). A contrast evaluation value of the generated shift addition signal (refocus signal) is calculated, an MTF peak position of the imaging signal is estimated from the contrast evaluation value, and a second detection defocus amount is detected.

  FIG. 13 shows a schematic explanatory diagram of the refocus processing in the one-dimensional direction (column direction, horizontal direction) by the first focus detection signal and the second focus detection signal acquired by the image sensor of the present embodiment. An imaging surface 800 in FIG. 13 corresponds to the imaging surface 800 illustrated in FIGS. 5 and 6. In FIG. 13, i is an integer, and the first focus detection signal of the i-th pixel in the column direction of the image sensor arranged on the imaging surface 800 is schematically represented by Ai, and the second focus detection signal is schematically represented by Bi. The first focus detection signal Ai is a light reception signal of a light beam incident on the i-th pixel at the principal ray angle θa (corresponding to the pupil partial region 501 in FIG. 5). The second focus detection signal Bi is a light reception signal of a light beam incident on the i-th pixel at the principal ray angle θb (corresponding to the pupil partial region 502 in FIG. 5).

  The first focus detection signal Ai and the second focus detection signal Bi have not only light intensity distribution information but also incident angle information. Therefore, the first focus detection signal Ai is translated along the angle θa to the virtual imaging plane 810, and the second focus detection signal Bi is translated along the angle θb to the virtual imaging position 810 and added. A refocus signal at the virtual imaging plane 810 can be generated. Translating the first focus detection signal Ai along the angle θa to the virtual imaging plane 810 corresponds to a +0.5 pixel shift in the column direction, and the second focus detection signal Bi is virtually linked along the angle θb. Translating to the image plane 810 corresponds to a -0.5 pixel shift in the column direction. Therefore, the first focus detection signal Ai and the second focus detection signal Bi are relatively shifted by +1 pixel, and Ai and Bi + 1 are added in correspondence with each other, whereby a refocus signal on the virtual imaging plane 810 can be generated. Similarly, the first focus detection signal Ai and the second focus detection signal Bi are shifted by an integer and added to generate a shift addition signal (refocus signal) on each virtual imaging plane corresponding to the integer shift amount. .

  The contrast evaluation value of the generated shift addition signal (refocus signal) is calculated, and the MTF peak position of the imaging signal is estimated from the calculated contrast evaluation value, thereby performing the second focus detection of the refocus method.

  FIG. 14 shows a schematic diagram of the flow of the second focus detection process of the present embodiment. The operation of FIG. 14 is executed by the focus detection signal generation unit, the image sensor 107 as the second focus detection unit, the image processing circuit 125, and the CPU 121 of the present embodiment.

  In step S210, a focus detection area for performing focus adjustment is set from the effective pixel area of the image sensor. The image sensor 107 generates a first focus detection signal from the light reception signal of the first focus detection pixel in the focus detection area, and generates a second focus detection signal from the light reception signal of the second focus detection pixel in the focus detection area. .

  In step S220, the first focus detection signal and the second focus detection signal are each subjected to three-column addition processing in the column direction for suppressing the signal data amount, and further, the Bayer for converting the RGB signal into the luminance Y signal. (RGB) addition processing is performed. These two addition processes are combined into a second pixel addition process. If necessary, one or both of the three-pixel addition processing and the Bayer (RGB) addition processing may be omitted.

  In step S230, the second filter processing is performed on the first focus detection signal and the second focus detection signal. An example of a pass band of the second filter processing of the present embodiment is indicated by a broken line and a dotted line in FIG. In the present embodiment, focus detection is performed from the small defocus state to the vicinity of the best in-focus position by the refocus second focus detection. Therefore, the pass band of the second filter process is configured to include a higher frequency band than the pass band of the first filter process.

  If necessary, second filter processing is performed using a Laplacian (second-order differential) [1, -2,1] filter that performs edge extraction of the subject signal in the second filter processing, as indicated by the dotted line in FIG. The pass band may be configured as a higher frequency band. By extracting the high frequency component of the subject and performing the second focus detection, the focus detection accuracy can be further improved.

  In step S240, a second shift process for relatively shifting the first focus detection signal and the second focus detection signal after the second filter process in the pupil division direction is performed and added to generate a shift addition signal (refocus signal). Generate.

  In step S240, a contrast evaluation value (second evaluation value) is further calculated from the generated shift addition signal.

  The kth first focus detection signal after the second filter processing is A (k), the second focus detection signal is B (k), and the range of number k corresponding to the focus detection area is W. The contrast evaluation value (second evaluation value) RFCON is calculated by Expression (2), where s2 is the shift amount by the second shift process and Γ2 is the shift range of the shift amount s2.

  By the second shift process of the shift amount s2, the kth first focus detection signal A (k) and the k-s2nd second focus detection signal B (k-s2) are added in correspondence with each other, and the shift addition signal is obtained. Generate. The absolute value of the shift addition signal is calculated, the maximum value in the range of the focus detection area W is taken, and the contrast evaluation value (second evaluation value) RFCON (s2) is calculated. If necessary, the contrast evaluation value (second evaluation value) calculated for each row may be added over a plurality of rows for each shift amount.

  In step S250, a real-value shift amount at which the contrast evaluation value is the maximum value is calculated from the contrast evaluation value (second evaluation value) by subpixel calculation, and is set as the peak shift amount p2. The second detection defocus amount (Def2) is obtained by multiplying the peak shift amount p2 by the image height of the focus detection area, the F value of the imaging lens (imaging optical system), and the second conversion coefficient K2 corresponding to the exit pupil distance. Is detected. If necessary, the first conversion coefficient K1 and the second conversion coefficient K2 may be the same value.

  In this embodiment, the second focus detection unit of the refocus method performs a second filter process and a second shift process on the first focus detection signal and the second focus detection signal, and adds them to generate a shift addition signal. Then, the contrast evaluation value is calculated from the shift addition signal, and the second detection defocus amount is detected from the contrast evaluation value.

  In the imaging device of this embodiment, as shown in FIGS. 4 and 5, the imaging pixel is obtained by adding the light beam received by the first focus detection pixel and the light beam received by the second focus detection pixel. The light beam is received. Unlike the first focus detection using the phase difference method, the second focus detection using the refocus method performs focus detection using a shift addition signal (refocus signal) of the first focus detection signal and the second focus detection signal. Therefore, since the light beam corresponding to the shift addition signal used in the second focus detection and the light beam corresponding to the imaging signal are substantially the same, each aberration of the imaging optical system (spherical aberration, astigmatism, coma aberration, etc.) ) On the shift addition signal and the influence on the imaging signal are substantially the same. Therefore, the detection focus position (position where the second detection defocus amount is 0) calculated by the refocus second focus detection and the best focus position of the imaging signal (MTF peak position of the imaging signal) are approximately Therefore, the focus detection can be performed with higher accuracy than the first focus detection of the phase difference method.

  An example of the first focus detection signal (broken line) and the second focus detection signal (solid line) at the best focus position of the image pickup signal at the peripheral image height of the image pickup device of the present embodiment shown in FIG. FIG. 15 shows the first focus detection signal (broken line) and the second focus detection signal (solid line) after applying the above. Further, the first focus detection signal (broken line) and the second focus detection signal (solid line) after the second filter processing are shifted by a relative shift of -2, -1, 0, 1, 2, and shifted for addition. An example of the addition signal (refocus signal) is shown in FIG. It can be seen that the peak value of the shift addition signal changes as the shift amount changes. An example of the contrast evaluation value (second evaluation value) calculated from each shift addition signal is shown in FIG.

  FIG. 12 shows an example of the second detection defocus amount (solid line) by the refocus second focus detection in the present embodiment. The horizontal axis is the set defocus amount, and the vertical axis is the detected defocus amount. The first focus detection signal and the second focus detection signal shown in FIG. 10 are the first focus detection signal and the second focus detection signal when the set defocus amount is 0 [mm] in FIG. It can be seen that at the best in-focus position with the set defocus amount 0, the second detection defocus amount by the second focus detection is suppressed to be smaller than the first detection defocus amount by the first focus detection, and the focus detection can be performed with high accuracy. .

  Therefore, in the present embodiment, the refocus second focus detection is more accurate than the phase difference first focus detection in the vicinity of the best focus position with the set defocus amount 0 of the imaging optical system. Focus detection is possible.

[Refocusable range]
On the other hand, since there is a limit to the refocusable range, the range of the defocus amount that can be detected with high accuracy by the refocus second focus detection is limited.

  A schematic explanatory diagram of a refocusable range in the present embodiment is shown in FIG. If the allowable circle of confusion is δ and the aperture value of the imaging optical system is F, the depth of field at the aperture value F is ± Fδ. On the other hand, the effective aperture value F01 (F02) in the horizontal direction of the pupil partial region 501 (502) narrowed by dividing by NH × NV (2 × 1) becomes dark as F01 = NHF. The effective depth of field for each first focus detection signal (second focus detection signal) is ± NHFδ and NH times deep, and the focusing range is widened by NH times. Within the range of effective depth of field ± NHFδ, a focused subject image is acquired for each first focus detection signal (second focus detection signal). Therefore, the refocusing process for refocusing (refocusing) after shooting is performed by the refocusing process of translating the first focus detection signal (second focus detection signal) along the principal ray angle θa (θb) shown in FIG. )can do. Therefore, the defocus amount d from the imaging surface where the focus position can be readjusted (refocused) after shooting is limited, and the refocusable range of the defocus amount d is approximately the range of Expression (3). .

| D | ≦ NH · F · δ (3)
The permissible circle of confusion δ is defined by δ = 2ΔX (the reciprocal of the Nyquist frequency 1 / (2ΔX) of the pixel period ΔX). If necessary, the reciprocal of the Nyquist frequency 1 / (2ΔXAF) of the period ΔXAF (= 6ΔX: in the case of 6 pixel addition) of the first focus detection signal (second focus detection signal) after the second pixel addition processing is allowed to be perturbed. The circle δ = 2ΔXAF may also be used.

  The defocus amount range in which the refocus second focus detection can detect the focus with high accuracy is generally limited to the range of the expression (3), and the defocus range in which the focus detection can be performed with high accuracy by the second focus detection is as follows. The range is equal to or smaller than the defocus range in which the first focus detection of the phase difference method can be performed. As shown in FIG. 6, the relative shift amount and defocus amount in the horizontal direction between the first focus detection signal and the second focus detection signal are approximately proportional.

  Therefore, the present embodiment is configured such that the shift range of the second shift process of the refocus second focus detection is equal to or smaller than the shift range of the first shift process of the phase difference first focus detection.

  In the focus detection of this embodiment, the first focus detection is performed to adjust the focus from the large defocus state to the small defocus state of the imaging optical system, and the vicinity of the best focus position from the small defocus state of the imaging optical system. The second focus detection is performed in order to adjust the focus up to. Therefore, it is desirable that the pass band of the second filter processing of the second focus detection includes a higher frequency band than the pass band of the first filter processing of the first focus detection. In addition, it is desirable that the pixel addition number in the second pixel addition process for the second focus detection is equal to or less than the pixel addition number in the first pixel addition process for the first focus detection.

  As described above, when the aperture value (F value) of the imaging optical system is equal to or smaller than the predetermined aperture value, the focus detection accuracy of the first focus detection of the phase difference method may be lowered. Therefore, if necessary, when the aperture value of the imaging optical system is equal to or smaller than the predetermined aperture value, the second detection defocus amount is obtained by the refocus second focus detection in addition to the phase difference first focus detection. Therefore, it is desirable to detect focus and to perform highly accurate focus detection.

  In the present embodiment, since the pupil region is divided into two pupils in the horizontal direction, the horizontal MTF peak position of the imaging signal can be detected. If necessary, the difference between the MTF peak position in the horizontal direction of the imaging signal and the MTF peak position in the imaging signal (average of the MTF peak positions in the horizontal and vertical directions of the imaging signal) is held as a correction value, and the second detection defocus is performed. The amount may be corrected.

  A schematic diagram of the flow of the focus detection process of the present embodiment is shown in FIG. In the present embodiment, the first focus detection of the phase difference method is performed until the absolute value of the defocus amount of the imaging optical system is equal to or less than the predetermined value 1, and the lens is driven to reduce the large defocus state of the imaging optical system from the small defocus state. Adjust the focus to the defocused state. Thereafter, until the absolute value of the defocus amount of the imaging optical system becomes a predetermined value 2 (<predetermined value 1) or less, the second focus detection of the refocusing method is performed to drive the lens, and the small defocus of the imaging optical system The focus is adjusted from the state to the vicinity of the best focus position.

  In step S100, the first detection defocus amount (Def1) is detected by the first focus detection by the phase difference method. When the detected magnitude | Def1 | of the first defocus amount (Def1) is larger than the predetermined value 1, in step S101, the lens is driven according to the first defocus amount (Def1), and the process returns to step S100. . When the detected magnitude | Def1 | of the first defocus amount (Def1) is equal to or smaller than the predetermined value 1, the process proceeds to step S200.

  In step S200, the second detection defocus amount (Def2) is detected by the second focus detection by the refocus method. If the detected magnitude | Def2 | of the second defocus amount (Def2) is larger than the predetermined value 2 (<predetermined value 1), in step S201, the lens is driven according to the second defocus amount (Def2). And return to step S200. When the detected magnitude | Def2 | of the second defocus amount (Def2) is equal to or smaller than the predetermined value 2, the focus adjustment operation is terminated.

  With the above configuration, the difference between the detection focus position calculated from the focus detection signal and the best focus position of the imaging signal is suppressed, and high-precision focus detection is possible.

[Indicator display method]
Next, a method for displaying the defocus amount up to the in-focus position on the MF indicator using these focus detection methods will be described.

  FIG. 20 is an example of the MF indicator used in the present embodiment. Reference numeral 901 denotes an AF frame of the camera. When the user places the AF frame at an arbitrary position where the user wants to focus, focus detection is performed using the first focus detection method and the second focus detection method in that region. .

  Next, 902 indicates the in-focus position, and the scale of the indicator indicated by 903 indicates the current defocus amount. When the user rotates the focus ring of the lens while looking at this indicator, the scale of the indicator decreases as shown in FIG. 22 and approaches the in-focus state. It becomes a state.

  At this time, in order to enable the user to operate not only in the remaining defocus amount but also in the direction in which the focus ring is rotated (rotation direction), as shown in FIG. The direction of rotation of the ring matches. In this way, when the user looks at the indicator, the user can immediately know whether the subject is the front pin or the rear pin, and can intuitively grasp the direction in which the focus ring is rotated.

  Next, an embodiment for allowing the indicator to move smoothly even when the focus detection method is switched will be described.

  As for the first focus detection method and the second focus detection method, as described above, the second focus detection method has a narrower focus detection range but higher focus detection accuracy. Therefore, when the defocus amount is large, focus detection is performed using the first focus detection method, and switching to the second focus detection method when approaching the in-focus position enables more accurate focus detection. .

  When using the AF function of the camera, the focus detection method can be switched smoothly without being noticed by the user. However, in the case where the user performs the focus adjustment with the MF while looking at the indicator as assumed in the present embodiment, the defocus detection value may change when the focus detection method is switched. In this case, there is a possibility that the scale of the indicator may be greatly advanced at once, or may be returned. When such a thing occurs, the scale of the indicator may move in the direction opposite to the direction in which the focus ring is rotated, which may be confusing to the user.

  Therefore, in the present embodiment, a difference value (calibration value) between the defocus amounts calculated in the first focus detection and the second focus detection is calculated, and the calibration value is added to the first focus detection result. Display with an indicator. Thus, the scale of the indicator is changed as smoothly (continuously) as possible in switching between the first focus detection method and the second focus detection method.

  In order to obtain the calibration value, each defocus amount is within a range where the focus detection can be performed by the second focus detection method, that is, within a range where both the first focus detection method and the second focus detection method can calculate the defocus amount. (Def1, Def2) is acquired, and the difference value is stored in the in-camera memory as a calibration value (C1) as shown in the following equation.

C1 = Def1-Def2
C1 obtained in this way is added to Def1 to calculate Def1 ′.

Def1 ′ = Def1 + C1
By using Def1 ′ obtained here as the defocus amount when displaying the indicator, the scale of the indicator smoothly moves when the focus is switched from the first focus detection to the second focus detection, and the user is not confused. MF can be assisted.

  The calibration value C1 used here is a value written in a memory in the camera or the lens, and it is assumed that a value written as a design value when the camera / lens is manufactured is used. However, it may be possible to obtain the defocus amounts Def1 and Def2 by the first focus detection and the second focus detection, calculate the difference value C1, and record it in the memory when focusing is performed by the user.

(Second Embodiment)
Next, a second embodiment will be described.

  In the first embodiment, a difference value between the defocus amount (Def1) for the first focus detection and the defocus amount (Def2) for the second focus detection is calculated as a calibration value and added to Def1, but the calibration is performed. The calibration value C1 is not always universal, and the calibration value may differ depending on the subject, the scene, and the shooting conditions.

  For example, the calibration value may be different when the illuminance is low, when the subject has a low contrast, or when the luminance is high. Further, as an imaging condition, the calibration value may be different even when the F value is different.

  Therefore, a more preferable indicator display can be realized by using a configuration in which the calibration value can be set individually according to the type of subject and the scene.

  An example of a calibration table used at this time is shown in FIG. FIG. 23 is a table showing conditions and calibration values used at that time. It is only necessary to detect which condition is applied during shooting and use a calibration value corresponding to the detected condition.

  FIG. 23 shows different types of subjects and shooting conditions, but a two-dimensional table as shown in FIG. 24 may be used, and an optimum calibration value corresponding to the type of subjects and shooting conditions may be used. It may be used.

(Other embodiments)
In the above embodiment, the case where the first and second focus detection methods using the imaging surface phase difference method are used is shown, but the present invention can be applied even when other methods are used. For example, the present invention is applicable to any focus detection method that is an external measurement method used in a video camera or the like, or any other focus detection method that can calculate the defocus amount up to the in-focus position.

  Further, the focus detection method is not limited to two, and the present invention can be applied even when three or more focus detection methods are combined.

  Furthermore, in the present embodiment, the display is performed with the bar-shaped indicator as shown in FIG. 20, but the shape is not limited to this. For example, the present invention provides the defocus amount itself that is the basis for display in a format in which the color of the display frame is changed according to the defocus amount and a format in which the numerical value of the defocus amount itself is displayed. It applies if it uses the method.

  The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

Claims (10)

An imaging device that drives a lens to focus on a subject and captures an image of the subject,
A plurality of focus detection means for detecting the in-focus state of the lens by different methods;
Switching means for switching the plurality of focus detection means according to the in-focus state of the lens;
Display means for displaying a defocus amount of the lens detected by the plurality of focus detection means;
When the plurality of focus detection means are switched by the switching means, display of the defocus amount of the lens detected by the focus detection means used before switching and detection by the focus detection means used after switching. Adjusting means for adjusting the value displayed by the display means so that the display of the defocus amount of the lens is continuously connected;
An imaging apparatus comprising: The plurality of focus detection means include
A first focus detection pixel that receives a light beam that passes through a first pupil partial region of the lens, and a light beam that passes through a second pupil partial region of the lens that is different from the first pupil partial region. An imaging element in which a plurality of second focus detection pixels and imaging pixels that receive a light beam that passes through a pupil region obtained by combining the first pupil partial region and the second pupil partial region of the lens are arranged When,
Generating means for generating a first focus detection signal from the signal of the first focus detection pixel and generating a second focus detection signal from the signal of the second focus detection pixel;
Detecting means for calculating a correlation amount from the first focus detection signal and the second focus detection signal, and detecting a first defocus amount from the correlation amount;
The imaging apparatus according to claim 1, further comprising: a first focus detection unit having The plurality of focus detection means include
A first focus detection pixel that receives a light beam that passes through a first pupil partial region of the lens, and a light beam that passes through a second pupil partial region of the lens that is different from the first pupil partial region. An imaging element in which a plurality of second focus detection pixels and imaging pixels that receive a light beam that passes through a pupil region obtained by combining the first pupil partial region and the second pupil partial region of the lens are arranged When,
Generating means for generating a first focus detection signal from the signal of the first focus detection pixel and generating a second focus detection signal from the signal of the second focus detection pixel;
The first focus detection signal and the second focus detection signal are shifted and added to generate an addition signal, a contrast evaluation value is calculated from the addition signal, and a second defocus is calculated from the evaluation value. Detecting means for detecting the amount;
The image pickup apparatus according to claim 1, further comprising: a second focus detection unit including:   The adjustment means adds the calibration value to the defocus amount of the lens detected by the focus detection means used before the switching, thereby detecting the focus detection means used before the switching. A value displayed by the display unit is adjusted so that the display of the defocus amount of the lens and the display of the defocus amount of the lens detected by the focus detection unit used after switching are continuously connected. The imaging device according to any one of claims 1 to 3.   The imaging apparatus according to claim 4, wherein the calibration value is set according to an F value of the lens.   6. The imaging apparatus according to claim 4, wherein the calibration value is set according to a type of subject.   The direction of the scale indicating the defocus amount of the lens of the display means toward the in-focus position is the same as the rotation direction of a ring for performing manual focus of the lens. The imaging device according to any one of the above. A method of controlling an imaging device including a plurality of focus detection units that drive a lens to focus on a subject, capture an image of the subject, and detect a focus state of the lens by different methods,
A switching step of switching the plurality of focus detection means according to the focusing state of the lens;
A display step of displaying a defocus amount of the lens detected by the plurality of focus detection means;
When the plurality of focus detection means are switched by the switching step, display of the defocus amount of the lens detected by the focus detection means used before switching and detection by the focus detection means used after switching. An adjustment step of adjusting the value displayed in the display step so that the display of the defocus amount of the lens is continuously connected;
A method for controlling an imaging apparatus, comprising:   The program for making a computer perform each process of the control method of Claim 8.   A computer-readable storage medium storing a program for causing a computer to execute each step of the control method according to claim 8.