JP2022170797A - Imaging device and lens device - Google Patents

Abstract

To provide a lens interchangeable imaging system capable of easily maintaining pan-focus imaging even when a zoom operation is performed.SOLUTION: A lens device 100 is detachably attached to an imaging device 200. The imaging device includes an imaging element 201 and acquisition means 06 for acquiring hyperfocal distance of the lens device. The acquisition means acquires information about focal distance of the lens device, and when a zoom operation is performed in the imaging device or the lens device, acquires the hyperfocal distance using the information about focal distance and correction information according to zoom magnification set by the zoom operation.SELECTED DRAWING: Figure 1

Description

The present invention relates to a lens-interchangeable imaging device and a lens device.

As one of imaging methods, there is pan-focus imaging in which the depth of field is deepened and the subject is focused from a short distance to infinity. The user calculates the hyperfocal distance from the nominal focal length of the lens, the number of pixels of the image sensor, and the set aperture value, and manually moves the focus lens to the lens position corresponding to the hyperfocal distance to set the pan focus. It is possible to However, such pan-focus setting requires the user to have specialized knowledge and skill.

Japanese Patent Application Laid-Open No. 2002-200000 discloses a lens-integrated imaging device that automatically performs pan-focus imaging as a countermeasure against AF failure in which the subject cannot be brought into focus by autofocus (AF). Further, Japanese Patent Application Laid-Open No. 2002-200000 discloses a lens-integrated image pickup device that allows selection between a normal imaging mode for AF and a quick-shooting mode for deep-focus imaging.

JP 2006-227133 A Japanese Patent Application Laid-Open No. 2003-140025

The lens-integrated imaging apparatuses disclosed in Patent Literatures 1 and 2 can automatically perform pan-focus setting when performing pan-focus imaging. However, Patent Literatures 1 and 2 do not disclose automatic pan-focus setting in a lens-interchangeable imaging system in which various types of lenses can be attached to the imaging device.

In addition, some interchangeable lens imaging systems have an optical zoom function of the lens or a digital zoom function that electronically magnifies a portion of the image generated by the imaging. Since the hyperfocal distance also changes when the optical zoom is performed, it becomes impossible to maintain deep focus imaging at the position of the focus lens before the optical zoom. Further, when digital zooming is performed, the amount of blurring on the enlarged image increases, although the amount of optical blurring on the imaging device does not change. Therefore, deep focus imaging cannot be maintained at the position of the focus lens before the digital zoom.

SUMMARY OF THE INVENTION The present invention provides an imaging device and a lens device that can easily maintain pan-focus imaging even when a zoom operation is performed in an interchangeable-lens imaging system.

An imaging device as one aspect of the present invention is detachably attached to a lens device. The imaging device has an imaging device and an acquisition means for acquiring the hyperfocal distance of the lens device. The acquisition means acquires information about the focal length of the lens device, and when a zoom operation is performed in the imaging device or the lens device, acquires information about the focal length and correction information according to the zoom magnification set by the zoom operation. is used to obtain the hyperfocal distance.

Further, a control method as another aspect of the present invention is applied to an image pickup apparatus having an image pickup element and having a detachable lens device. The control method includes the steps of obtaining information about the focal length of the lens device, and, when a zoom operation is performed in the imaging device or the lens device, correction according to the information about the focal length and the zoom magnification set by the zoom operation. and obtaining a hyperfocal distance using the information. A program that causes the imaging apparatus to execute processing according to the control method also constitutes another aspect of the present invention.

According to the present invention, it is possible to realize a lens-interchangeable imaging system that can easily maintain pan-focus imaging even when a zoom operation is performed.

1 is a block diagram showing the configuration of an interchangeable lens imaging system that is an embodiment of the present invention; FIG. 4 is a flow chart showing processing performed in Examples 1 to 3; 10 is a flowchart showing processing performed in the fourth embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of an interchangeable lens imaging system that is an embodiment of the present invention. The imaging system is composed of a camera body 200 as an imaging device and an interchangeable lens 100 as a lens device detachably and communicatively attached to the camera body 200 .

The interchangeable lens 100 is mechanically and electrically connected to the camera body 200 via a mount (not shown). The interchangeable lens 100 has an imaging lens as an imaging optical system and a lens microcomputer (hereinafter referred to as a lens microcomputer) 111, and power is supplied from the camera body 200 via a power supply terminal (not shown) provided on the mount. to operate.

The camera body 200 has an image sensor 201 including phase difference focus detection pixels, a signal processing circuit 202 , a recording processing section 203 , a display section 204 , an operation section 205 and a camera microcomputer (hereinafter referred to as camera microcomputer) 206 .

The imaging element 201 photoelectrically converts (images) a subject image formed by an imaging lens and outputs an analog imaging signal as an electrical signal. The analog imaging signal is converted into a digital imaging signal by an A/D conversion circuit (not shown).

The signal processing circuit 202 generates a video signal (captured image) by performing various types of image processing on the digital imaging signal. The signal processing circuit 202 also generates focus information indicating the contrast state of the subject image, that is, the focus state of the imaging lens, and luminance information indicating the exposure state from the video signal.

A display unit 204 is a rear monitor or an electronic viewfinder, and displays a live view image corresponding to the image signal from the signal processing circuit 202 so that the user can check the subject and composition. The recording processing unit 203 stores the video signal from the signal processing circuit 202 as still image data or moving image data in a recording medium (not shown).

A camera microcomputer 206 as camera control means and acquisition means controls the camera body 200 in accordance with inputs from an imaging instruction switch, various setting switches, and the like included in the operation unit 205 . The operation unit 205 also includes a switch (pan focus setting switch) for instructing pan focus setting, which will be described later. The pan-focus setting switch may be a dedicated switch, or may be a function-assignable switch to which the user assigns a function as the pan-focus setting switch using a custom function.

Also, the camera microcomputer 206 communicates with the lens microcomputer 111 via a communication terminal provided on the mount. Specifically, the camera microcomputer 206 sends to the lens microcomputer 111 an aperture control command according to the luminance information and a focus control command according to the focus information generated from the output of the phase difference detection pixels of the image sensor 201. Send. The lens microcomputer 111 also transmits information used for pan focus control, which will be described later, to the camera microcomputer 206 .

The imaging lens included in the interchangeable lens 100 includes a field lens 101 , a variable power (zoom) lens 102 , an aperture unit 103 , an anti-vibration lens 104 and a focus lens 105 . The interchangeable lens 100 has a zoom operation ring (not shown), a focus operation ring 110 and the lens microcomputer 111 described above.

The lens microcomputer 111 transmits lens data including identification information and optical information of the interchangeable lens 100 to the camera body 200 in response to a transmission request transmitted from the camera body 200 (camera microcomputer 206). Also, the lens microcomputer 111 receives camera data including various information of the camera body 200 from the camera body 200 in response to a reception request transmitted from the camera body 200 .

The lens microcomputer 111 causes the aperture control unit 107 to open and close the aperture unit 103 according to the aperture control command received from the camera body 200 . The position of the diaphragm blades of the diaphragm unit 103 is detected by a sensor such as a Hall element, and the diaphragm position data is output to the lens microcomputer 111 . Upon receiving a drive command from the lens microcomputer 111, the aperture control unit 107 opens and closes the aperture blades by driving an aperture actuator composed of a stepping motor, a voice coil motor, or the like. As a result, the aperture unit 103 adjusts the amount of light.

Also, the lens microcomputer 111 causes the focus control unit 109 to drive the focus lens 105 in the optical axis direction according to the focus control command received from the camera body 200 . The position of the focus lens 105 is detected using a sensor such as a photointerrupter, and the focus position data is output to the lens microcomputer 111 . The lens microcomputer 111 calculates the target position of the focus lens 105 based on the focus position data and the focus drive amount data included in the focus control command. The focus control unit 109 receives a drive command including a target position from the lens microcomputer 111 and drives a focus actuator such as a stepping motor to move the focus lens 105 . Autofocus (AF) is thereby performed. The lens microcomputer 111 and the focus control unit 109 constitute lens control means.

Note that the lens microcomputer 111 can also cause the focus control unit 109 to move the focus lens 105 according to the amount of operation of the focus operation ring 110 . This enables manual focusing (MF).

The zoom lens 102 is driven in the optical axis direction via a drive mechanism (not shown) when the user operates the zoom operation ring. As a result, magnification is performed by changing the focal length of the imaging lens. A zoom position detection unit 106 detects the position (zoom position) of the zoom lens 102 using a sensor such as a variable resistor, and outputs the zoom position data to the lens microcomputer 111 . The lens microcomputer 111 uses the zoom position data to generate information about the focal length.

The anti-vibration lens 104 reduces (corrects) image blur caused by camera shake or the like by moving (shifting) in a direction perpendicular to the optical axis of the imaging lens. The anti-vibration control unit 108, which has received an anti-vibration command from the lens microcomputer 111, drives an anti-vibration actuator composed of a voice coil motor or the like according to the vibration detected by a vibration sensor such as a vibration gyroscope (not shown). The anti-vibration lens 104 is shifted. Thereby, optical image stabilization is performed.

Next, pan focus control in this embodiment will be described. The camera microcomputer 206 starts pan focus control by detecting the operation of the operation unit 205 (pan focus setting switch) by the user. For example, the camera microcomputer 206 calculates the hyperfocal distance using the focal length of the imaging lens received from the lens microcomputer 111 and transmits a pan focus drive command to the lens microcomputer 111 together with the hyperfocal distance.

The hyperfocal distance is the closest distance at which infinity is included in the depth of field, and can be obtained by the following formula (1).
h=f ² /(Fδ) (1)
h: hyperfocal distance [mm]
F: Aperture value (F number)
f: Focal length of imaging lens [mm]
δ: Permissible circle of confusion diameter [mm]
Further, for example, the lens microcomputer 111 obtains the position of the focus lens 105 at which the imaging lens is in the pan-focus state (hereinafter referred to as the pan-focus position) as the lens position corresponding to the received hyperfocal distance. Then, the drive amount from the current position of the focus lens 105 to the pan-focus position is calculated. Further, the lens microcomputer 111 causes the focus control unit 109 to drive the focus lens 105 by the calculated drive amount. Thereby, setting of the pan-focus state (pan-focus setting) is automatically performed.

Further, the camera body 200 of this embodiment has a digital zoom operation section 301 . When the user operates the digital zoom operation unit 301 (hereinafter referred to as digital zoom operation), the signal processing unit 202 performs digital zoom as processing for enlarging a part of the captured image. At this time, the signal processing unit 202 performs enlargement processing with a digital zoom magnification set according to the amount of operation of the digital zoom operation unit 301 . A recording processing unit 203 and a display unit 204 respectively record and display an enlarged digital zoom image (enlarged image).

Note that the digital zoom operation unit 301 may be integrated with the display unit 204 having a touch panel, or may be provided as a digital operation ring or switch (not shown) on the interchangeable lens 100 .

The signal processing circuit 202 transmits information on the above-described digital zoom magnification to the correction coefficient acquisition unit 302 in the camera microcomputer 206 . A correction coefficient acquisition unit 302 acquires a correction coefficient as correction information according to the digital zoom magnification. The correction coefficient is a coefficient for correcting the hyperfocal distance calculated by Equation (1) (hereinafter referred to as the reference hyperfocal distance) according to the digital zoom magnification. In this embodiment, the digital zoom magnification is used as the correction coefficient. use. The camera microcomputer 206 multiplies (applies) the reference _hyperfocal distance h0 by the correction coefficient X (=Z) as shown in the following equation (2) to obtain a hyperfocal distance correction value (hereinafter referred to as correction Calculate the hyperfocal distance h ₁ .

h1 ₌ h0*X ( ₂ )
X: Correction coefficient h ₀ : Reference hyperfocal distance [mm]
h ₁ : corrected hyperfocal distance [mm]
A correction coefficient that divides the reference _hyperfocal distance h0 may be used.

The flowchart in FIG. 2 shows the processing executed by the camera microcomputer 206 and the lens microcomputer 111 for pan focus control in this embodiment. The camera microcomputer 206 and lens microcomputer 111 each execute this process according to a computer program. Processing starting from Step 101 indicates processing executed by the camera microcomputer 206 , and processing starting from Step 201 indicates processing executed by the lens microcomputer 111 . Arrows between the two flow charts indicate the direction of information communication.

The camera microcomputer 206, which has started processing in step 101, receives information about the current focal length of the imaging lens from the lens microcomputer 111 in step 102. FIG. Information about the focal length will be described later. Since the focal length of the imaging lens changes depending on the user's operation of the zoom operation ring, it is desirable to perform polling at short intervals. If polling cannot be performed in a sufficiently short period, the order of Step 102 and Step 103, which will be described later, may be exchanged.

In step 103, the camera microcomputer 206 waits for the operation of the pan focus setting switch by the user.

At Step 104, the camera microcomputer 206 confirms whether or not the user has performed a digital zoom operation. If the digital zoom operation has not been performed, the process proceeds to step 106 , and if it has been performed, the process proceeds to step 105 .

In Step 105, the camera microcomputer 206 (correction coefficient acquisition unit 302) receives the digital zoom magnification from the signal processing circuit 202 and acquires a correction coefficient (digital zoom magnification = correction coefficient in this embodiment) according to the digital zoom magnification. Then, the process proceeds to Step S106.

In Step 106, the camera microcomputer 206 uses the focal length obtained from the information received from the lens microcomputer 111 in Step 102, the aperture value set in imaging in the pan-focus state, and the permissible circle of confusion diameter to obtain the formula (1 ) to calculate (obtain) the hyperfocal distance. When entering this step after step 105, the correction coefficient X obtained in step 105 and the reference hyperfocal distance h0 calculated by the equation ( ₁ ) are substituted into the equation (2) to obtain the corrected _hyperfocal distance h1. calculate.

Instead of calculating the hyperfocal distance using formula (1), hyperfocal distance data calculated by different combinations of focal lengths, aperture values, and permissible circle of confusion diameters are stored in advance as table data. , the corresponding hyperfocal distance may be read (acquired).

Next, in Step 107 , the camera microcomputer 206 transmits information on the hyperfocal distance (or corrected hyperfocal distance) acquired in Step 106 to the lens microcomputer 111 . The information about the hyperfocal distance may be information indicating the hyperfocal distance itself, or information that can be converted to the hyperfocal distance by the lens microcomputer 111, such as a parameter (variable) of a function indicating the hyperfocal distance. good.

Next, in Step 108 , the camera microcomputer 206 transmits a pan focus drive command to the lens microcomputer 111 . Then, the camera microcomputer 206 terminates the processing at step 109 .

On the other hand, the lens microcomputer 111, which started processing in step 201, obtains the current focal length of the imaging lens from the zoom position data obtained from the zoom position detection unit 106 in step 202, and transmits information about the focal length to the camera microcomputer 206. Send. The information about the focal length may be information indicating the focal length itself, or information such as a zoom position that can be converted into the focal length by the camera microcomputer 206 .

Next, in Step 203 , the lens microcomputer 111 receives information regarding the hyperfocal distance from the camera microcomputer 206 . Further, the lens microcomputer 111 receives a pan focus drive command from the camera microcomputer 206 in Step 204 .

Next, in step 205, the lens microcomputer 111 converts the hyperfocal distance obtained from the information received in step 203 into a pan-focus position, and calculates the difference (driving amount) from the current position of the focus lens 105 to the pan-focus position. do.

Next, in Step 206, the lens microcomputer 111 causes the focus control unit 109 to drive the focus lens 105 by the drive amount calculated in Step 205, thereby obtaining a deep focus state. Then, the lens microcomputer 111 terminates the processing at Step 207 .

According to the present embodiment, it is possible to easily perform pan-focus imaging in a situation (arbitrary timing) intended by the user. Further, according to the present embodiment, it is possible to easily maintain deep-focus imaging even when digital zooming is performed.

In Example 1, the digital zoom magnification was directly used as the correction coefficient. In contrast, in the second embodiment, the digital zoom magnification is divided into a plurality of magnification ranges, and a correction coefficient set for each magnification range is used. The correction coefficient in this case is also a correction coefficient according to the digital zoom magnification.

In this embodiment, in Step 105 of FIG. 2, the correction coefficient acquisition unit 302 obtains Z=1, 1.1 to 2 in the correction coefficient table shown in Table 1, in which the digital zoom magnification Z received from the signal processing circuit 202 is stored in advance. , 2. It is determined whether the image belongs to any magnification range of 1 to 4. Then, when Z=1, the correction coefficient X=1 is read from the correction coefficient table and obtained, when Z=1 to 2, X=2 is obtained, and when Z=2 to 4, X=4 is obtained. get. Note that the correction coefficient table of Table 1 is merely an example, and the division of the digital zoom magnification into magnification ranges and the correction coefficient for each magnification range may be different from those in Table 1.

The camera microcomputer 206 substitutes the acquired correction coefficient X and the reference hyperfocal distance h0 calculated by the equation ( ₁ ) into the equation (2) to calculate the corrected _hyperfocal distance h1.

By setting a correction coefficient for each magnification range of the digital zoom magnification Z like the above correction coefficient table, there is no need to newly calculate a corrected hyperfocal distance even if the digital zoom magnification is changed within the same magnification range. As a result, the processing load on the camera microcomputer 206 can be reduced.

As a third embodiment, processing when the digital zoom operation is performed again after the corrected hyperfocal distance is calculated according to the digital zoom operation in the first and second embodiments will be described.

In this case, as shown in the following formula (3), the corrected hyperfocal distance h ₁ at the time of the first digital zoom operation is combined with the correction coefficient X ₁ and the reference hyperfocal distance h The corrected hyperfocal distance (h ₀ ×X ₁ ) calculated from ₀ is added or subtracted. When the digital zoom magnification becomes larger due to the digital zoom operation again, it is added, and when the digital zoom magnification becomes smaller, it is subtracted. As a result, the corrected _hyperfocal distance h2 corresponding to the digital zoom operation is calculated again. That is, the corrected hyperfocal distance is reacquired.

The correction coefficient X1 may be the digital zoom magnification itself after the _second digital zoom operation, or may be a value acquired from the correction coefficient table shown in the second embodiment.

h2 ₌ h1 _± ( _h0 *X1) ( ₃ )
In this way, every time a digital zoom operation is performed, the corrected hyperfocal distance corresponding to the digital zoom magnification at that time is acquired, and the focus lens is moved to the pan-focus position corresponding to the corrected hyperfocal distance. Imaging can be maintained.

In Examples 1 to 3, correction of the hyperfocal distance when digital zooming is performed in the camera body 200 has been described. However, even when optical zooming is performed by moving the zoom lens 102 in the interchangeable lens 100 after transmission and reception of lens focal length information, the hyperfocal distance can be similarly corrected.

The flowchart in FIG. 3 shows processing executed by the camera microcomputer 206 and the lens microcomputer 111 for pan focus control in the fourth embodiment.

The camera microcomputer 206 performs the same processing as in the first embodiment in Steps 101-103. Then, in Step 104 ′, the camera microcomputer 206 checks through communication with the lens microcomputer 111 whether or not an optical zoom operation (zoom operation ring operation) has been performed on the interchangeable lens 100 . If the optical zoom operation has not been performed, the process proceeds to Step 106', and if it has been performed, the process proceeds to Step 105'.

In Step 105', the camera microcomputer 206 receives the optical zoom magnification set by the optical zoom operation from the lens microcomputer 111, and acquires a correction coefficient corresponding to the optical zoom magnification. Here, the optical zoom magnification is the rate of change with respect to the focal length f of the lens received in Step 102, and is defined as correction coefficient _X2 . As in the first embodiment, the correction coefficient may be the optical zoom magnification itself, or may be a value set for each magnification range of the optical zoom magnification. Then, the camera microcomputer 206 proceeds to Step S106'.

In Step 106', the camera microcomputer 206 uses the focal length obtained from the information received from the lens microcomputer 111 in Step 102, the aperture value set in the pan-focus imaging, and the permissible circle of confusion diameter, according to Equation (1): Calculate (obtain) the hyperfocal distance. When entering this step after step 105′, the correction coefficient X ₂ obtained in step 105′ and the reference hyperfocal distance h ₀ calculated by the equation (1) are substituted into the following equation (4), and after optical zooming , the corrected _hyperfocal distance h3 is calculated.

h ₃ =(f×X ₂ ) ² /(Fδ)=h ₀ ×X ₂ ² (4)
In this embodiment, data on hyperfocal distances calculated by combinations of different focal lengths, aperture values, and permissible circle of confusion diameters are stored in advance as table data, and the corresponding hyperfocal distances are read out from the table data ( acquisition).

The processing from Step 107 to Step 109 is the same as in the first embodiment. Further, the processing of Steps 201 to 207 performed by the lens microcomputer 111 is the same as in the first embodiment.

According to this embodiment, it is possible to easily perform pan-focus imaging in a situation (at any timing) intended by the user. Further, even when optical zooming is performed, pan-focus imaging can be easily maintained.
(Other examples)
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

Each embodiment described above is merely a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

100 Interchangeable Lens 200 Camera Body 206 Camera Microcomputer 302 Correction Coefficient Acquisition Unit

Claims (11)

An imaging device in which a lens device is detachably attached,
an imaging device;
an acquisition means for acquiring the hyperfocal distance of the lens device,
The acquisition means is
obtaining information about the focal length of the lens device;
Acquiring the hyperfocal distance using the information about the focal length and correction information according to the zoom magnification set by the zoom operation when the imaging device or the lens device performs a zoom operation. An imaging device characterized by: 2. The imaging apparatus according to claim 1, wherein the correction information is a correction coefficient applied to the hyperfocal distance obtained using the information on the focal length. 3. The imaging apparatus according to claim 1, wherein the acquisition means uses the value of the zoom magnification as the correction information. The acquisition means is
holding the correction information set for each of the plurality of zoom magnification ranges;
3. The imaging apparatus according to claim 1, wherein the hyperfocal distance is obtained using the correction information of the zoom magnification range set by the zoom operation. 5. The imaging apparatus according to any one of claims 1 to 4, wherein the zoom magnification is a zoom magnification of digital zoom for an image obtained using the imaging element. The imaging apparatus according to any one of claims 1 to 4, wherein the zoom magnification is an optical zoom magnification of the lens device. When the zoom operation is performed again after obtaining the hyperfocal distance using the correction information, the obtaining means obtains the hyperfocal distance obtained using the correction information and the zoom operation again. The imaging apparatus according to any one of claims 1 to 6, wherein the hyperfocal distance is reacquired using the correction information corresponding to the set zoom magnification. The imaging device is capable of communicating with the lens device,
The acquisition means is
receiving information about the focal length from the lens apparatus;
8. The imaging apparatus according to claim 1, wherein information for driving a focus lens of the lens device to a position corresponding to the hyperfocal distance is transmitted to the lens device. A lens device detachably and communicatively attached to the imaging device according to claim 8,
the focus lens;
and lens control means for driving the focus lens to a position corresponding to the hyperfocal distance. A control method for an imaging device having a detachable lens device and an imaging element, comprising:
obtaining information about the focal length of the lens apparatus;
obtaining the hyperfocal distance using the information about the focal length and the correction information according to the zoom magnification set by the zoom operation when a zoom operation is performed in the imaging device or the lens device; A control method characterized by having 11. A program for causing a computer of an imaging device, to which a lens device is detachably attached and having an imaging element, to execute processing according to the control method according to claim 10.

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