JP2016090816A5 - Imaging apparatus and control method thereof, imaging optical system and control method thereof - Google Patents

Description

The present invention relates to an imaging apparatus and a control method thereof , and an imaging optical system and a control method thereof, and more particularly to an automatic focus detection technique.

To achieve the above object, an imaging apparatus of the present invention, there can perform the automatic focus detection of the photographing optical system using an image signal obtained from the focus detection area set, detachable co Nbatarenzu an imaging apparatus, when the converter lens is mounted, the information related to the yield difference of the photographing optical system, converting means for converting based on the imaging magnification of said converter lens, said converter lens If not attached by using the information related to aberrations of the imaging optical system which has not been converted by said converting means, associated with the translated aberration by the converting means when the converter lens is mounted using information, the characteristics of the prior SL signal is used to obtain the results of the autofocus detection, the difference between the focus state by the difference between the characteristics of the signal of the photographed object image A calculation means for calculating a correction value for positive to, and control means for controlling the position of the focus lens in which the imaging optical system has, based on the of the automatic focus detection corrected by the correction value results.

The AF control unit of the camera MPU 125 acquires each of the above-described focus evaluation values, and moves the focus lens 104 in a predetermined direction along the optical axis direction through the lens MPU 117. Then, the various evaluation values described above are calculated based on the newly obtained image data, and the focus lens position at which the total integrated evaluation value is the maximum value is detected.

In S1, the camera MPU 125 sets a focus detection area. Here, it is assumed that three focus detection areas as shown in FIG. 6 are set for both phase difference AF and contrast AF. In S2, the camera MPU 125 sets a closeness determination flag in the RAM 125b to 1.

An example of the spatial frequency BP correction information will be described with reference to FIG. 10B showing a defocus modulation transfer function (MTF) of the photographing optical system. In FIG. 10B, the horizontal axis indicates the position of the focus lens 104, and the vertical axis indicates the intensity of the MTF. The four types of curves depicted in FIG. 10B are MTF curves for each spatial frequency and indicate the higher spatial frequency in the order of MTF1, MTF2, MTF3, and MTF4. The MTF curve of the spatial frequency F1 (lp / mm) corresponds to MTF1, and similarly, the spatial frequencies F2, F3, and F4 (lp / mm) correspond to MTF2, MTF3, and MTF4, respectively. Further, LP4, LP5, LP 6, LP 7 shows the position of the focus lens 104 corresponding to the maximum value of the defocus MTF curve. The stored spatial frequency BP correction information is obtained by discretely sampling the curve of FIG. As an example, in the present embodiment, MTF data is sampled at 10 focus lens positions with respect to one MTF curve. For example, MTF1 (n) (1 ≦ n ≦ 10) is 10 for MTF1. Data is stored.

The block diagram of the imaging apparatus (FIG. 2), the explanatory diagrams of the respective focus detection methods (FIGS. 3 to 5), the explanatory diagram of the focus detection area (FIG. 6), the flowchart of the focus detection process and various BP correction value calculation processes. (FIGS. 1A and 1B , FIG. 7, and FIG. 9A) are also used in this embodiment. The flowchart of the spatial frequency BP correction value calculation process (FIG. 10A) and the explanatory diagram of each evaluation band (FIG. 11) are also used.

The block diagram of the imaging apparatus (FIG. 2), the explanatory diagrams of the respective focus detection methods (FIGS. 3 to 5), the explanatory diagram of the focus detection area (FIG. 6), the flowchart of the focus detection process and various BP correction value calculation processes. (FIGS. 1A and 1B , FIG. 7, and FIG. 9A) are also used in this embodiment. In addition, the diagrams related to the spatial frequency BP correction value calculation processing (FIGS. 10B to 10C) are also used.

The converter lens unit 600 includes a converter lens 601 and a converter memory 602, and is a photographing lens that changes the focal length of the lens unit 100 that forms an optical image of a subject. In the following description, the lens unit 100 is referred to as a “master lens 100” in order to distinguish it from the converter lens 601. When the converter lens unit 600 is mounted, the zoom function is realized by the first lens group 101 , the second lens group 103, and the converter lens 601. The converter memory 602 stores in advance optical information necessary for automatic focus adjustment. The camera MPU 125 controls the operation of the master lens 100 by executing programs stored in, for example, a built-in nonvolatile memory, the lens memory 118, and the converter memory 602.

The block diagram of the imaging device (FIG. 2 ), the explanatory diagrams of each focus detection method (FIGS. 3 to 5), the explanatory diagram of the focus detection area (FIG. 6), and the explanatory diagram of each evaluation band (FIG. 11) Since it is common also in 7th Embodiment, it also diverts in the following description.

Claims (21)

It is capable of executing the automatic focus detection of the photographing optical system using an image signal obtained from the set focus detection area, a removable imaging device co Nbatarenzu,
When the converter lens is mounted, and conversion means for information related to the yield difference of the photographing optical system is converted based on the imaging magnification of said converter lens,
When the converter lens is not attached , information related to the aberration of the photographing optical system that is not converted by the converter is used, and when the converter lens is attached, the information is converted by the converter. by using the information related to aberrations, prior SL and characteristics of the signal used to obtain the results of the autofocus detection, to correct a difference in the focus state by the difference between the characteristics of the signal of the photographed object image A calculation means for calculating a correction value;
An image pickup apparatus comprising: control means for controlling a position of a focus lens included in the photographing optical system based on a result of the automatic focus detection corrected by the correction value.   The imaging apparatus according to claim 1, wherein the information related to the aberration of the photographing optical system is information corresponding to at least one of the focus detection region, a position of a focus lens, and a spatial frequency.   The information related to the aberration of the photographing optical system is information on the imaging position of the photographing optical system for each spatial frequency of the subject,
  The conversion means further corrects information related to the aberration of the photographing optical system based on the aberration information of the converter lens, and the calculation means corrects the image formation corrected based on the aberration information of the converter lens. The imaging apparatus according to claim 1, wherein a correction value for correcting the automatic focus detection result is calculated using position information. The conversion means includes at least one of a change in position of the focus detection region, a change in focus position, a change in spatial frequency, and a change in spatial frequency caused by the imaging magnification of the converter lens; The imaging apparatus according to any one of claims 1 to 3 , wherein information relating to aberrations of the photographing optical system is converted so as to correct aberrations.   When the converter lens is mounted, the conversion means converts the information regarding spherical aberration, astigmatism, and chromatic aberration of the photographing optical system to a plurality of focus points corresponding to maximum values of modulation transfer functions at a plurality of different spatial frequencies. The imaging according to any one of claims 1 to 4, wherein information related to an aberration of the photographing optical system expressed by a lens position is converted based on photographing magnification and aberration information of the converter lens. apparatus. The converting means calculates the local maximum value when the converter lens is not mounted, the difference between the local maximum value and a predetermined reference value as a square of the magnification determined based on the magnification of the converter lens. 6. The image pickup apparatus according to claim 5 , wherein information relating to aberration of the photographing optical system is converted so as to shift by the amount of the shift. The converting means is configured to obtain the spatial frequency obtained by multiplying the spatial frequency when the converter lens is not mounted by a magnification determined on the basis of the magnification of the converter lens. 6. The imaging apparatus according to claim 5 , wherein information relating to the aberration of the image is converted. The converting means has a position obtained by dividing the position of the focus detection area when the converter lens is not mounted by dividing the position of the focus detection area by a value determined based on the magnification of the converter lens. 6. The imaging apparatus according to claim 5 , wherein information relating to aberrations of the photographing optical system is converted. The imaging apparatus according to claim 5 , wherein the conversion unit adds aberration information of the converter lens to the information related to the converted aberration for each spatial frequency. Information on a plurality of focus lens positions corresponding to maximum values of modulation transfer functions corresponding to the plurality of different spatial frequencies is defined as a function having a first parameter and a second parameter as variables,
The image pickup device stores defocus MTF intermediate information using information on a plurality of focus lens positions corresponding to maximum values of modulation transfer functions corresponding to the plurality of different spatial frequencies and the first parameter. Further comprising
It said calculating means uses the second parameter and the defocus MTF intermediate information, the imaging apparatus according to any one of claims 5 to 9, characterized in that to calculate the correction value. The first parameter is a variable corresponding to chromatic aberration, astigmatism, and position of the focus detection region of the photographing optical system,
The imaging apparatus according to claim 10 , wherein the second parameter is a variable corresponding to a spherical aberration of the photographing optical system. The first parameter is a variable corresponding to chromatic aberration, astigmatism, and spherical aberration of the photographing optical system,
The imaging apparatus according to claim 10 , wherein the second parameter is a variable corresponding to a position of the focus detection region. And the converting means, in a case where predetermined conditions are satisfied, an imaging apparatus according to any one of claims 1 to 12, characterized in that no correction of the information related to the aberrations. It is capable of executing a set focal automatic focus detection of the photographing optical system using an image signal obtained from the detection region, a control method in a removable imaging device co Nbatarenzu,
If the previous SL converter lens is mounted, a conversion step of the yield difference information of the photographing optical system is converted based on the imaging magnification of said converter lens,
And characteristics of the signals used to using the aberration information of the imaging optical system that is not converted by the conversion step, to obtain the results of the previous SL automatic focus detection in the case of front Symbol converter lens is not mounted, calculating a correction value for correcting a difference in focus state due to the difference between the characteristic of the signal of the photographed object image,
Using the aberration information converted by said conversion step if the previous SL converter lens is mounted, before SL signal is used to obtain the results of the autofocus detection characteristics and, of the signal of the photographed object image calculating a correction value for correcting a difference in focus state due to the difference between the characteristic,
And controlling the position of the focus lens included in the imaging optical system based on the results of the previous SL the automatic focus detection corrected by the correction value,
A method for controlling an imaging apparatus, comprising:   An imaging device capable of performing automatic focus detection of an imaging optical system using an image signal obtained from a set focus detection area, and an automatic imaging optical system using an image signal obtained from the set focus detection area An imaging optical system capable of mounting a converter lens mounted on an imaging device capable of performing focus detection,
  When the converter lens is mounted, conversion means for converting information related to the aberration of the imaging optical system based on the imaging magnification of the converter lens;
  Calculation means for calculating a correction value for correcting the automatic focus detection result based on the information related to the converted aberration of the photographing optical system;
  A photographic optical system comprising:   16. The photographing optical system according to claim 15, wherein the information related to the aberration of the photographing optical system is information corresponding to at least one of the focus detection region, the position of the focus lens, and the spatial frequency.   The calculation unit corrects a difference in focus state due to a difference between a characteristic of a signal used for acquiring the result of the automatic focus detection and a characteristic of a signal of a photographing target image, which is caused by an aberration of the photographing optical system. The photographic optical system according to claim 15, wherein a correction value for calculating the correction value is calculated.   The information related to the aberration of the photographing optical system is information on the imaging position of the photographing optical system for each spatial frequency of the subject,
  The calculation means calculates a correction value for correcting the automatic focus detection result using information on the imaging position corrected based on aberration information of the converter lens. The taking optical system described in 1.   The conversion means corrects at least one of a change in position of the focus detection region, a change in focus position, and a change in spatial frequency caused by the imaging magnification of the converter lens, and the aberration of the converter lens. The photographic optical system according to claim 15, wherein information related to aberrations of the photographic optical system is converted.   16. The photographing optical system according to claim 15, wherein the conversion unit does not correct the aberration information when a predetermined condition is satisfied.   An imaging device capable of performing automatic focus detection of an imaging optical system using an image signal obtained from a set focus detection area, and an automatic imaging optical system using an image signal obtained from the set focus detection area A control method of a photographing optical system capable of attaching a converter lens attached to an imaging device capable of performing focus detection,
  When the converter lens is attached, a conversion step of converting information related to the aberration of the photographing optical system based on the photographing magnification of the converter lens;
  A calculation step of calculating a correction value for correcting the automatic focus detection result based on the converted information relating to the aberration of the photographing optical system;
  A method for controlling a photographic optical system, comprising:

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