JP2007156304A - Camera, camera system, and interchangeable lens device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera capable of detecting the focus with high accuracy and high speed, and to provide a camera system and an interchangeable lens device. <P>SOLUTION: The camera equipped with an imaging device, a focus decision means and a focus detection means by a phase difference detection system is constituted, to have means (1) to (3). (1): A correction value arithmetic calculation means for arithmetically calculating a correction value for correcting a detection error in the focus detection means, on the basis of a result from the focus decision means and the result of detection by the focus detection means. (2) An environmental circumstances decision means for determining the environmental circumstances caused by external factors at photographing. (3): A storage means for associating the correction value arithmetically calculated by the correction value arithmetic calculation means with information, according to the environmental circumstances decided by the environmental circumstances decision means and storing them. The detection errors in the focus detection means are corrected on the basis of the correction value stored by the storage means and information according to the environmental circumstances. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a camera, a camera system, and an interchangeable lens device, and more particularly to focus detection of a digital single lens reflex camera system to which an interchangeable lens can be attached and detached.

As a focus detection means of a digital single-lens reflex camera with interchangeable lenses, a phase difference type focus detection means is mainly used as in the conventional single-lens reflex camera for silver salt film.
In addition, a hybrid method that performs focus detection by combining a focus detection unit using a contrast detection method and a phase detection method focus detection unit as used in a conventional video camera has been proposed.

In the phase difference detection method, focus detection is performed as follows.
A part of the photographing light beam is divided into two, and these two light beams are respectively imaged on the line sensor.
Two image shift directions and shift amounts on the line sensor due to the light beam divided into two are detected.
Based on these detection results, the moving direction and moving amount of the focusing lens necessary for focusing on the planned focal plane (a plane conjugate with the imaging plane) are calculated, and the focusing lens is driven.
According to such a phase difference detection method, it is possible to directly calculate the moving direction and moving amount of the focus adjustment lens necessary for focusing, so that focusing can be obtained quickly. Conventionally, for example, Patent Document 1 proposes such a phase difference detection method.

In contrast detection, focus detection is performed as follows.
A high-frequency component is extracted from a video signal generated based on a signal output from an image sensor for capturing a subject image.
Then, the level of the high frequency component is observed at a predetermined sampling interval, and the focus adjustment lens is driven in the direction in which the level of the high frequency component is directed toward the peak, and finally the level of the high frequency component reaches the predetermined peak range. Determined to be in focus.
According to such a contrast detection method, since the focus determination is performed using the video signal obtained based on the output signal from the image sensor that captures the subject image, the subject is focused with high accuracy. Obtainable.
Conventionally, for example, Patent Document 2, Patent Document 3 and the like have proposed using such a contrast detection method.

Further, in the hybrid method, by combining the phase difference method and the contrast detection method, it is possible to perform coarse adjustment with the phase difference method and perform fine adjustment with the contrast detection method to accurately perform focus detection.
Conventionally, for example, Patent Document 4 proposes such a hybrid system.

Furthermore, the focus detection method using only the phase difference method may not provide sufficient focusing accuracy. For example, in Patent Document 5, an error that differs depending on each individual is corrected to achieve high-precision focusing. There has been proposed an imaging apparatus that performs focus control.
In the focus detection method using only the phase difference method, the main reason why sufficient focusing accuracy cannot be obtained is that the light flux of the imaging optical system that forms the image to be observed or photographed is generally different from the light flux captured by the focus detection means. Can be mentioned.
In addition, in the phase difference detection type focus detection means, the focal position or defocus amount that should be determined by the amount of aberration in the longitudinal (optical axis) direction is converted into the image displacement related to the lateral aberration. Looking for.
For this reason, when there is an aberration in the image pickup optical system, it is conceivable that a difference occurs between the two depending on the aberration correction state.
In order to solve such a problem, for example, a focus detection signal D representing an out-of-focus amount is obtained using a correction value C unique to each imaging lens.
DC = DC (1)
Correction means for correcting by the above is provided.
Based on the obtained corrected focus detection signal, the whole or a part of the imaging optical system is driven by the driving means, and the lens is controlled so that the best imaging position coincides with the imaging surface.
By the way, in this method, a design correction value is generally used as the correction value C, and such a correction value does not include an error generated in the manufacturing stage.
For this reason, errors that occur in the manufacturing stage also cause a failure to obtain sufficient focusing accuracy.
For this reason, Patent Document 5 proposes a method of detecting the focus peak position by analyzing the contrast of the captured image, and calculating and storing a correction value from the difference between the value and the focus detection position by the phase difference method. Has been.
JP 05-257062 A JP 59-174807 A JP 2001-83406 A JP 2003-84191 A JP 2003-295047 A

However, in the case of Patent Document 5 in the above conventional example, there is a case where satisfaction is not always obtained in correcting the error and performing high-precision focusing control.
That is, in this method, there are cases where different correction values are calculated depending on the environment for calculating the correction values.
Here, the environment refers to the type, temperature, humidity, color of the subject, etc. of the light source that illuminates the subject.
The phase difference type focus detection system performs detection using a light beam that has passed through a photographing lens. However, since the detection sensor itself is different from the image sensor used for photographing, the spectral sensitivity distribution is generally different. .
Therefore, there is a difference in correction values between shooting under sunlight and shooting under a fluorescent lamp.
In addition, temperature, humidity, etc. affect the focus detection system and cause errors in detection.

On the other hand, when the hybrid method is used for a digital single-lens reflex camera with interchangeable lenses, it is possible to perform focus adjustment accurately by performing coarse adjustment by the phase difference method and fine adjustment by the contrast detection method.
However, in this method, since the final focus detection is performed by the contrast detection method, the time required for focus detection becomes long, and it is difficult to perform focus detection at high speed.
In addition, a digital single lens reflex camera using an optical viewfinder has the following disadvantages.
That is, in a digital single-lens reflex camera using an optical viewfinder, the light flux taken from the imaging optical system is supplied with a light amount to each of the viewfinder optical system, phase difference type focus detection means, and contrast detection type focus detection means. It will lead without damage. Therefore, since the light flux is switched in time series, the detection time becomes long.

  In view of the above problems, an object of the present invention is to provide a camera, a camera system, and an interchangeable lens device that can perform high-precision and high-speed focus detection.

  In order to solve the above-described problems, the present invention provides a camera, a camera system, and an interchangeable lens device configured as follows.

The camera according to the present invention includes a camera including an imaging device, a focus determination unit using a contrast detection method, and a focus detection unit using a phase difference detection method, and includes the following units (1) to (3). .
(1) Correction value calculation means for calculating a correction value for correcting a detection error for the in-focus position detected by the focus detection means based on the result from the focus determination means and the detection result of the focus detection means.
(2) Environmental condition determination means for determining an environmental condition caused by an external factor at the time of shooting.
(3) Storage means for storing the correction value calculated by the correction value calculation means in association with the information based on the environmental situation determined by the environmental situation determination means.
The camera according to the present invention is characterized in that the detection error in the focus detection unit is corrected based on the correction value stored in the storage unit and information based on the environmental situation.
Here, the image pickup device has a configuration for picking up an image formed by the image pickup optical system, and the focus determining means is a focus position of the image pickup optical system by a contrast detection method based on an output signal from the image pickup device. It has the structure which performs this determination.
Further, the focus detection means has a configuration that uses the light flux from the imaging optical system to detect the focus of the imaging optical system by a phase difference detection method.
The camera according to the present invention is characterized in that the environmental condition caused by the external factor is the type of light source that illuminates the subject, temperature, humidity, or the color of the subject.
The camera of the present invention is characterized in that the focus determination means is configured to detect contrast while defocusing.
The camera according to the present invention is characterized in that the focus determination means is configured to detect the contrast of each image by performing still image shooting with different focus states.
The camera of the present invention is characterized in that the storage means is configured to be able to store a correction value for each identification number for identifying each lens of a plurality of lenses constituting the imaging optical system.
The camera according to the present invention is characterized in that a calibration mode for performing the calculation of the correction value and the determination of the environmental condition can be set.
Further, the camera of the present invention is characterized in that it can automatically perform the calculation of the correction value and the determination of the environmental situation without configuring the calibration mode.
The camera system of the present invention includes any one of the above-described cameras and an interchangeable lens device that can be attached to and detached from the camera.
In addition, the interchangeable lens device of the present invention is configured to be detachable from any of the cameras described above.

  According to the present invention, it is possible to realize a camera, a camera system, and an interchangeable lens device that can perform high-precision and high-speed focus detection.

Hereinafter, embodiments of the present invention will be described.
[Embodiment 1]
As Embodiment 1 of the present invention, a lens interchangeable digital single-lens reflex camera system configured by applying the configuration of the present invention will be described.
FIG. 1 shows a configuration of a digital single-lens reflex camera system in the present embodiment.
In FIG. 1, 1 is a lens body, 2 is an imaging optical system as an objective lens, 3 is lens driving means, 4 is lens state detection means, 5 is lens control means, and 6 is storage means.
7 is a contact point, 8 is a camera body, 11 is an image sensor, 12 is focus detection means, 13 is camera control means, 14 is calculation means, 15 is storage means, and 16 is focus determination means.
Reference numeral 17 denotes an optical axis, 19 denotes a main mirror, 20 denotes a sub mirror, 28 denotes a focusing screen, 29 denotes an eyepiece optical system, 30 denotes a pentaprism, and 100 denotes light source discrimination means.

The camera system according to this embodiment includes a lens body 1 and a camera body 8.
The imaging optical system 2 accommodated in the lens body 1 is composed of one or a plurality of lens groups, and the focal length and focus can be changed by moving all or a part of them.
The lens driving unit 3 is a driving unit that adjusts the focus state by moving all or a part of the optical axis 17 of the imaging optical system 2 and the lenses constituting the imaging optical system 2.
The lens state detection unit 4 is a detection unit that detects the focal length of the imaging optical system 2, that is, the zoom state and the focus state.
Here, in this lens state detection means 4, a known method, for example, an electrode for an encoder provided on a lens barrel that rotates or moves in order to change the focal length of the imaging optical system 2, and a detection electrode in contact therewith, etc. Is used.
Accordingly, it is possible to detect the moving state of the lens that moves when the focal length (zoom state) and focus of the imaging optical system 2 are changed, or the amount that characterizes the moving state.
The lens control means 5 is a control means composed of a CPU or the like that controls the entire lens body 1 including a storage means 6 constituted by a ROM or the like.

In the camera body 8, a main mirror 19, a focusing screen 28 on which an object image is formed, a pentaprism 30 for image reversal, and an eyepiece optical system 29 are provided, and a finder system is configured by these.
Further, in the camera body 8, a sub-mirror that guides the light beam transmitted through the main mirror 19 to a focus detection means, an image sensor 11 for photographing a subject image formed by the imaging optical system 2, and focus detection means. 12 is provided.
In the camera body 8, camera control means 13 including a CPU or the like that controls the entire camera body 8 is provided.
Further, in the camera body 8, focus determination means 16 for detecting the contrast of an image photographed by the image sensor and determining an in-focus position, an output from the focus determination means 16, and an output from the focus detection means 12 An arithmetic means 14 is provided for calculating a correction value based on the difference between.
Further, in the camera body 8, there is provided a storage means 15 for storing the difference amount calculated by the calculation means as correction information.
For the contrast detection by the focus determination unit 16, a contrast type focus detection unit according to a conventional example can be used.
The light source discriminating means 100 is a means for receiving a subject image formed on the focusing screen 28 and discriminating the type of light source from the intensity of infrared light.
The contact 7 is a contact provided in the lens body 1 and the camera body 8, and various information is communicated and power is supplied through the contact 7 when the contacts 7 are attached to each other.
In addition, the camera system according to the present embodiment is configured (not shown) so that a calibration mode for calculating and storing the correction information described above can be set.

Next, the configuration of the main part of the focus detection means 12 will be further described.
FIG. 2 shows the configuration of the main part of the focus detection means 12 in FIG.
In FIG. 2, 17 indicates the optical axis of the imaging optical system, and 18 indicates the position of the imaging plane of the imaging optical system 2 on which the imaging device 11 of FIG. 1 is placed.
19 is a semi-transparent main mirror disposed on the optical axis 17 of the imaging optical system 2, and 20 is a first reflection having a positive power disposed obliquely on the optical axis 17 of the imaging optical system 2. A mirror 21 is a paraxial image plane conjugate to the image plane 18 reflected by the first reflecting mirror 20.
Reference numeral 22 denotes a second reflecting mirror, reference numeral 23 denotes an infrared cut filter, and reference numeral 24 denotes an AF stop, which has two openings 24-1 and 24-2.
Reference numeral 25 denotes a secondary imaging system, which has two lenses 25-1 and 25-2 arranged corresponding to the two openings 24-1 and 24-2 of the AF diaphragm 24.
A photoelectric conversion element (sensor) 26 has two area sensors 26-1 and 26-2. Reference numeral 36 denotes a third reflecting mirror.

Here, the first reflecting mirror 20 has a curvature, and convergent power (refractive power) for projecting the two apertures 24-1 and 24-2 of the AF diaphragm 24 near the exit pupil of the photographing optical system 2. have.
Further, the first reflecting mirror 20 has a metal film such as aluminum or silver deposited so that only a necessary region reflects light, and also serves as a field mask that limits the range of focus detection. Yes.
In the other second reflecting mirror 22 and the third reflecting mirror 36 as well, only a minimum necessary region is deposited in order to reduce stray light incident on the photoelectric conversion element 26.
In addition, it is preferable to apply a light-absorbing paint or the like to a region that does not function as a reflecting surface of each reflecting mirror.

FIG. 3 is a plan view of the AF diaphragm 24 shown in FIG.
The AF diaphragm 24 has a configuration in which two horizontally long openings 24-1 and 24-2 are arranged in a direction in which the opening width is narrow.
In the drawing, the dotted lines indicate the respective optical systems 25-1 and 25 of the secondary imaging system 25 disposed behind the AF diaphragm 24 corresponding to the openings 24-1 and 24-2. -2.
FIG. 4 is a plan view of the photoelectric conversion element 26 shown in FIG.
The two area sensors 26-1 and 26-2 shown in FIG. 4 are obtained by arranging two area sensors in which pixels are two-dimensionally arranged as shown in FIG.

In the focus detection system having the above components, as shown in FIG. 2, the light beams 27-1 and 27-2 from the imaging optical system 2 are transmitted through the half mirror surface of the main mirror 19 and then the first reflecting mirror. 20 is reflected in a direction substantially along the inclination of the main mirror 19.
After the direction is changed again by the second reflecting mirror 22, each optical system of the secondary imaging system 25 passes through the two apertures 24-1 and 24-2 of the AF stop 24 via the infrared cut filter 23. It is condensed by 25-1 and 25-2.
And it reaches | attains on the area sensors 26-1 and 26-2 of the photoelectric conversion element 26 through the 3rd reflective mirror 36, respectively.
The light beams 27-1 and 27-2 in FIG. 2 indicate the light beam that forms an image at the center of an image sensor (not shown) arranged on the imaging surface 18, but the light beams that are imaged at other positions also. The photoelectric conversion element 26 is reached through a similar path.
As a whole, a distribution of two light amounts relating to a subject image corresponding to a predetermined two-dimensional area on the image sensor is formed on each area sensor 26-1, 26-2 of the photoelectric conversion element 26.

The focus detection unit 12 in FIG. 1 is based on the same detection principle as the focus detection method using the phase difference detection method conventionally used for the light amount distribution regarding the two subject images obtained as described above. The focus state of the imaging optical system 2 is detected.
In other words, the relative positional relationship in the vertical direction of the two area sensors 26-1 and 26-2 shown in FIG. 4 that is the separation direction of the subject image is calculated at each position of the area sensors 26-1 and 26-2. Then, the focus state of the imaging optical system 2 is detected, and the result is output as a defocus amount D.
However, if the lens is controlled based on the focus state detection signal regarding the amount of defocus directly obtained, an appropriate focus state may not be obtained.
For this reason, a correction value unique to each lens body 1 (imaging lens) is stored in the lens-side storage means 6, and correction for matching the best imaging position with the imaging surface can be performed using this.
However, since the correction value stored in the lens-side storage means does not include the individual difference of each lens and the individual difference of the focus detection means 12, there arises a disadvantage that an appropriate focus detection state cannot be obtained.

From the above, in the present embodiment, the following configuration is adopted in order to make the correction value a more accurate value.
That is, the contrast of the image signal obtained from the image sensor 11 is detected while changing the focus state of the lens by the lens driving unit 3, and the in-focus position is determined by the focus determination unit 16 from the contrast.
Then, the difference from the in-focus position detected by the focus detection unit 12 using the phase difference detection method described above is calculated by the calculation unit 14 and stored in the storage unit 15.
At this time, in the present embodiment, the light source discriminating unit 100 discriminates the type of the light source and stores it in the storage unit 15 at the same time.
Thereby, the correction value of the same light source type can be used at the time of photographing, and more accurate correction can be performed.
In the above description, the light source discrimination unit 100 discriminates the type of light source to obtain a correction value. However, the present invention is not limited to this.
For example, environmental information such as temperature and humidity can be stored simultaneously by various sensors provided in the camera, and correction can be made with higher accuracy in light of environmental information at the time of shooting. .

Next, the operation of the camera system incorporating the above contents in the present embodiment as a calibration mode will be described.
FIG. 5 shows a flowchart for explaining the operation of the camera system.
First, when the calibration mode is selected, the calibration mode is started automatically or when the photographer turns on the shutter switch (step 501).
Next, the lens driving means 3 defocuses the lens (step 502).
Next, the focus determination means 16 detects the contrast of the image signal obtained from the image sensor 11 with the lens defocused (step 503). Then, after repeating step 502 and step 503 a plurality of times, the focus position is determined from the defocus position where the image signal with the highest contrast among the detected contrasts is obtained, and focus position information is created (step 504). .

Next, phase difference type focus detection is performed using the focus detection means 12, and focus position information is created (step 505).
Next, the type of the light source is determined by the light source determination means 100 (step 506).
In this case, the light source discrimination may be, for example, a simple method of estimating the light source from the light intensity in the visible region and the light intensity in the infrared region, or by accurately measuring the light source by measuring the spectral intensity distribution. The method to do may be used.
Further, even the spectral intensity distribution information itself is effective light source information as correction value information under a specific light source.
Next, a difference between the focus position information determined by the focus determination means 16 and the focus position information created using the focus detection means 12 is calculated by the calculation means 14 (step 507).
Then, the calculated in-focus position correction value is stored in the storage unit 15 together with the light source information (step 508).
Here, the correction value stored according to the type of the light source discriminated during the operation of the focusing camera is the same type as the light source at the time of shooting.

The calibration is completed through the above operations.
Here, if there is a time lag between step 504, step 505, and step 507, an error may occur due to movement of the subject. Therefore, step 504, step 505, and step 507 may be performed simultaneously. desirable.
Further, as described above, if calibration is performed using a general subject, an error may occur due to movement of the subject, and therefore, a method using a specific calibration chart can be considered.
For example, a calibration chart is fixed to a wall or the like, and correction values are stored in a calibration mode.
According to the present embodiment, since the above-described light source discriminating means is provided, the calibration effective person can perform calibration without worrying about the light source environment when performing calibration.
Of course, even if a specific calibration chart is not used, according to the present embodiment, the calibration effective person can execute the calibration without worrying about the light source or the like.

Here, as a method for performing calibration, a method using a personal computer (hereinafter referred to as PC) or the like can be used.
In this case, for example, a method of projecting a chart on the PC screen by connecting to the PC or executing software on the PC and performing calibration using the chart can be employed.
As a result, it is possible to automatically set the display chart to an optimum size according to the focal length and shooting distance of the lens to be used.
Since the PC screen generally has a spectral intensity that does not contain much infrared light, such as a cathode ray tube or a liquid crystal screen, it is stored together with correction values in a form that identifies the light source as an environment affected by external factors. The method of the present invention is effective in improving the correction accuracy.
According to this embodiment, since the light source for which the correction value has been calculated can be recognized as a camera system, even if correction is performed on the PC screen, it is easy to estimate the correction amount necessary for shooting under sunlight, and the correct focus Matching is possible.

Further, for the contrast detection by the focus determination means 16, a contrast type focus detection means used in a conventional video camera may be used.
In addition, if the camera body is equipped with a mechanical shutter or an image sensor that cannot perform electronic shuttering is used and focus detection using the conventional contrast method cannot be performed, multiple images are taken. The contrast of the image may be detected.
The in-focus position correction value may be stored by rewriting the correction value C unique to each imaging lens described in the background art stored in the storage unit 6 provided in the lens.
Alternatively, it may be stored as a correction value different from the correction value C.
Further, the focus correction value may be stored in the storage means 15 provided in the camera body only as the focus position correction value or as a numerical value including the correction value C. May be.
Furthermore, in the calibration mode, it is more desirable to perform the calibration operation as described above for each subject distance, and obtain a focus position correction value for each identification information for identifying each lens.
In the calibration operation, the focus detection by the phase difference method is performed after the focus position information is generated by the focus determination unit.
However, the phase difference type focus detection is performed before the focus position information is created by the focus determination means, and the lens driving range in step 502 is close to the focus position detected by the phase difference type focus detection. limit.
As a result, calibration can be completed more quickly.

Next, the operation of the camera when actually taking a picture using the focus position correction value created in the calibration mode will be described.
FIG. 6 shows a flowchart for explaining the operation of the camera.
Here, the focus position correction value is stored in the storage means in the camera separately from the correction value C.
First, the release button is half-pressed (hereinafter referred to as 1st release) (step 601).
Thereby, the focus detection unit 12 performs focus detection by the phase difference method (step 602).
Next, the light source is discriminated by the light source discriminating means 100 (step 603).
Next, focus position information is created from the focus detection result of the focus detection means 12 (step 604).
Then, the focus position information is corrected using a correction value C unique to each imaging lens and a focus position correction value corresponding to the type of light source created in the calibration mode (step 605).
Next, the lens is driven by the lens driving means 3 based on the corrected in-focus position information, and the in-focus operation is completed (step 606).
Thereafter, shooting is performed by pressing the release button (hereinafter referred to as 2nd release) (step 607).

As described above, in addition to the focus position difference obtained from the focus detection unit 12 and the focus determination unit 16 that perform focus detection by the phase difference method, the light source determination unit 100 under the calibration mode further The light source type information is simultaneously stored in the storage unit 15.
By using the correction value based on the information stored in this way at the time of photographing, it is possible to detect the focus with high accuracy while maintaining the high speed by the phase difference method.
If the in-focus position correction value is stored as a numerical value including the correction value C in the storage means in the camera as described above, the correction value C needs to be communicated between the lens and the camera body. In addition, even faster focus detection is possible.

[Embodiment 2]
Next, Embodiment 2 of the present invention will be described.
The second embodiment is the same as the first embodiment except that the in-focus position correction value is automatically calculated without using the calibration mode.
FIG. 7 shows a flowchart for explaining the operation of the camera system.
First, calculation of a focus position correction value is started (step 701).
Next, using the focus detection means 12, focus detection is performed by a phase difference method, and focus position information is created (step 702).
Next, the lens is driven by the lens driving means 3 based on the in-focus position information, and an in-focus operation is performed (step 703).
Next, the minute lens is defocused from the lens position driven by the lens driving means 3 (step 704).
Next, the focus determination means 16 detects the contrast of the image signal from the image sensor in the defocused state (step 705).
Then, after repeating step 704 and step 705 a plurality of times, focus position information is created from the defocus position from which the image signal with the highest contrast among the detected contrasts was obtained (step 706).
Next, the light source is discriminated by the light source discriminating means 100 (step 707).
Next, the difference between the focus position information detected by the focus determination means 16 and the focus position information created using the focus detection means 12 is calculated by the calculation means 14 (step 708).
The in-focus position correction value calculated in this way is stored in the storage unit 15 together with the determined type of light source (step 709). With the operation as described above, the operation of automatically calculating the focus position correction value without using the calibration mode is completed.

Here, the timing for starting the calculation of the in-focus position correction value is performed when the photographer is not touching the release button.
At that time, a method of interrupting correction value calculation by the photographer's first release can be used.
Further, the photographing operation is performed a plurality of times while defocusing at a shutter speed less than 1/2 of the shutter speed set at the time of actual photographing.
A method of obtaining an image equivalent to shooting at the shutter speed set by the image processing after shooting is completed may be used.
The photographing operation when actually photographing using the in-focus position information difference amount created by the calibration may be performed by the same method as in the first embodiment.
Here, it is desirable that the focus detection described above is performed every time the lens is replaced. Therefore, when the lens is replaced and the focus detection and exposure correction values of the lens are not stored in the storage unit, it is desirable to warn the photographer that the correction value is not stored.
Further, in the present embodiment, the focus detection correction value is stored in a storage unit provided in the camera, but the conventional correction value stored in the storage unit provided in the lens is rewritten. May be.

The figure which shows the structure of the digital single-lens reflex camera system in Embodiment 1 of this invention. The figure which shows the structure of the principal part of the focus detection means in FIG. 1 which is Embodiment 1 of this invention. FIG. 3 is a plan view showing a configuration of an AF stop in FIG. 2 that is Embodiment 1 of the present invention. The top view which shows the structure of the photoelectric conversion element in FIG. 2 which is Embodiment 1 of this invention. 6 is a flowchart for explaining the operation of the camera system in a calibration mode according to the first embodiment of the present invention. 6 is a flowchart for explaining the operation of the camera when actually taking a picture using the in-focus position correction value created in the calibration mode according to the first embodiment of the present invention. 9 is a flowchart for explaining the operation of a camera system that automatically calculates a focus position correction value without using a calibration mode in Embodiment 2 of the present invention.

Explanation of symbols

1: Lens body 2: Imaging optical system 3: Lens drive means 4: Lens state detection means 5: Lens control means 6: Storage means 7: Contact point 8: Camera body 11: Image sensor 12: Focus detection means 13: Camera control means 14: Calculation means 15: Storage means 16: Focus determination means 17: Optical axis 18: Image plane 19: Main mirror
20: Sub mirror 21: Paraxial image plane 23: Infrared cut filter 24: AF stop 28: Focus plate 29: Eyepiece optical system 30: Penta prism 100: Light source discriminating means

Claims (9)

An image sensor for imaging an image formed by the imaging optical system;
Focus determining means for determining the in-focus position of the imaging optical system by a contrast detection method based on an output signal from the imaging element;
In a camera having a focus detection unit that detects a focus of the imaging optical system by a phase difference detection method using a light beam from the imaging optical system,
Correction value calculation means for calculating a correction value for correcting a detection error for the in-focus position detected by the focus detection means based on the result from the focus determination means and the detection result of the focus detection means;
Environmental status determination means for determining environmental status caused by external factors at the time of shooting;
Storage means for storing the correction value calculated by the correction value calculation means and information on the environmental situation determined by the environmental situation determination means in association with each other;
And a detection error in the focus detection unit is corrected based on a correction value stored in the storage unit and information on an environmental condition.   The camera according to claim 1, wherein the environmental condition caused by the external factor is a type of light source that illuminates the subject, temperature, humidity, or color of the subject.   The camera according to claim 1, wherein the focus determination unit is configured to be able to detect contrast while defocusing.   The said focus determination means is comprised so that the detection of the contrast of each image is possible by performing the still image photography from which a focus state differs in multiple times, The any one of Claims 1-3 characterized by the above-mentioned. The listed camera.   The storage means is configured to be able to store a correction value for each identification number for identifying each lens of the plurality of lenses constituting the imaging optical system. The camera according to item.   The camera according to any one of claims 1 to 5, wherein the camera is configured to be able to set a calibration mode for performing an operation of calculating the correction value and determining an environmental condition. .   6. The camera according to claim 1, wherein the camera is configured to automatically perform the calculation of the correction value and the determination of an environmental condition without configuring the calibration mode. The camera according to item.   A camera system comprising: the camera according to claim 1; and an interchangeable lens device that is attachable to and detachable from the camera.   An interchangeable lens device configured to be detachable from the camera according to any one of claims 1 to 7.

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