JP2002098884A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform accurate focus detection by calculating the positional change of an optical member with respect to the home position thereof due to the increase of the number of actuating times of an optical member and appropriately correcting deviation between a focusing position and the focusing position on an image-formation surface even when the optical path length of a focus detection optical system is changed by the positional change. SOLUTION: This camera has a light receiving means consisting of plural photoelectric conversion elements, and the optical member 107 moved to the home position in a photographing optical path from the outside of the photographing optical path at the time of detecting focus, and guiding luminous flux passing through a photographing lens to the light receiving means. It is provided with image forming parts 8a and 8b forming a specified image on the light receiving means by making the luminous flux incident on an effective range used to guide the luminous flux to the light receiving means on the optical member 107, and an arithmetic operation means for calculating the positional change of the optical member with respect to the home position based on light quantity distribution by the specified image on the light receiving means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera having a light receiving means and a focus optical system having an optical member operating in connection with a focus detection operation.

[0002]

2. Description of the Related Art Conventionally, a main mirror having a semi-transmissive portion for guiding a light beam passing through a photographing lens to a finder optical system,
A sub-mirror that guides the light flux passing through the semi-transmissive portion of the main mirror to a focus detection device. During focus detection and viewfinder observation, the main mirror and the sub-mirror enter the fixed position in the photographing optical path and stop at this position. In addition, there has been proposed a camera which is movable so as to retract a main mirror and a sub-mirror outside a photographing optical path during photographing.

In this type of camera, when the number of times of operation of the main mirror and the sub-mirror increases, the members related to the driving of the main mirror and the sub-mirror wear, and the rest positions of the main mirror and the sub-mirror at the time of focus detection change accordingly. And
There has been a problem that the focus position detected by the focus detection device and the focus position of the image forming plane are shifted due to a change in the optical path length of the light beam guided to the focus detection device.

Therefore, in Japanese Patent Application Laid-Open No. 9-54243, the relationship between the cumulative number of operations of the optical member and the correction amount of the focus detection signal is stored in advance, and when the focus is detected, the cumulative number of operations at that time and the previously stored operation are stored. A camera that corrects a focus detection signal based on the relationship between the number of times of integration and the amount of focus detection signal correction has been proposed.

FIG. 14 is a block diagram showing a main part of the camera disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 9-54243.

In FIG. 1, reference numeral 101 denotes a photographing lens;
1a is an optical axis of the photographing lens, and 102 is an image recording medium for forming an image of a subject passing through the photographing lens 101. 1
Reference numeral 03 denotes a main mirror having a semi-transmissive portion movably provided outside the photographing optical path at the time of photographing, and a part of a light beam having passed through the photographing lens 101, which is a finder including a focusing plate 104, a pentaprism 105, and an eyepiece 106. It leads to the optical system. On the other hand, the remaining light beam that has passed through the semi-transmissive portion of the main mirror 103 is reflected downward by a sub-mirror 107 configured to be movable in synchronization with the operation of the main mirror 103, and is composed of a pair of photoelectric conversion element arrays. The light is guided to a well-known phase difference type focus detection device 108 including an image sensor, a pair of secondary imaging lenses, a diaphragm having a pair of openings, a field lens, and the like.

Here, the principle of focus detection by the phase difference method will be described with reference to FIG. Note that portions denoted by the same reference numerals as those in FIG. 14 have the same functions. In FIG. 15, in order to eliminate the complexity of the drawing,
The main mirror 103 and the sub mirror 107 are omitted, a field lens 115, a stop 116 having a pair of openings,
An image sensor 118 including a pair of secondary imaging lenses 117, a pair of photoelectric conversion element arrays, and the like is deployed on the optical axis 101a of the photographing lens.

A light beam emitted from a point on the optical axis 101a passes through the photographing lens 101 and forms an image on a primary image forming surface 102a having an optically conjugate positional relationship with the image recording medium 102.
An image is formed on the image sensor 118 via the field lens 115, the aperture 116, and the secondary imaging lens 117 at a constant interval. The field lens 115
Are arranged so that the pupil 101b of the taking lens 101 and the entrance pupil of the pair of secondary imaging lenses 117, that is, the vicinity of the stop 116, form an image, and correspond to the pair of apertures of the stop 116. Is divided in the vertical direction in the figure.

With such a configuration, for example, the taking lens 1
When the light beam 01 is fed out to the left in the drawing and the light flux forms an image to the left of the image recording medium 102, the pair of images on the image sensor 118 is displaced in the direction of the arrow in the drawing. By detecting the relative shift amount of the pair of images with the image sensor 118, it is possible to adjust the focus of the photographing lens 101. The same applies to the case where the photographing lens 101 is retracted rightward in the figure. Also, the optical axis 101a of the taking lens 101
The same applies to other object points.

The focus of the photographing lens 101 is detected by using the focus detection device 108 based on the above principle.

Returning to FIG. 14, reference numeral 109 denotes a microcomputer for processing and controlling various operations of the camera. The microcomputer 109 includes a CPU 109a, a ROM 109b, a RAM 109c, and a program for storing programs relating to focus detection processing.
An EEPROM 109d (electrically erasable programmable ROM) is provided. 110 is the image sensor 11
The focus detection circuit 111 is connected to the main mirror 1.
Mirror driving means for moving the lens 03 out of the optical path for photographing, 11
Reference numeral 2 denotes a mirror driving circuit for driving the mirror driving unit 111, 113 denotes a lens driving unit for adjusting the focus of the photographing lens 101, and 114 denotes a lens driving circuit for driving the lens driving unit 113.

In an EEPROM 109d built in the microcomputer 109, a relationship between the number of times of operation of the main mirror 103 and the correction amount of the focus detection signal is stored in advance by experimental data, and is stored in the RAM 109b up to the present time. The total number of operations of the main mirror 103 and the EEP
The focus detection signal obtained by the focus detection device 108 and the focus detection circuit 110 is corrected in accordance with the focus detection processing operation stored in the ROM 109c, based on the relationship between the accumulated number of operations and the focus detection signal correction amount stored in the ROM 109d.
Accordingly, when the number of times of operation of the main mirror 103 and the sub-mirror 107 is increased, the member for holding the main mirror 103 and the sub-mirror 107 so that the main mirror 103 and the sub-mirror 107 are movable is worn. And the focus position detected by the focus detection device 108 and the focus detection circuit 110 and the focus position on the image recording medium 102 are shifted due to the change in the optical path length of the focus detection optical system.
Since the focus detection signal is corrected based on the total number of operations of the main mirror 103 at that time, highly accurate focus detection can be realized.

[0013]

However, for example, when the main mirror 103 is operated in a short-term intensive manner,
When the main mirror 103 is actuated after an appropriate time interval, the members holding the main mirror 103 and the sub-mirror 107 are different in the degree of wear and the degree of fatigue even if the accumulated number of operations is the same. The gap is also different. Nevertheless, in the above conventional example, the main mirror 103
Since the focus detection signal is uniformly corrected according to the number of times of the integration operation, it is impossible to appropriately correct the focus detection signal.

Further, the degree of wear and the degree of fatigue vary depending on the manufacturing error and the assembly error of the individual parts, and there is a problem that the focus detection signal cannot be properly corrected.

(Object of the Invention) A first object of the present invention is to calculate a change in position of an optical member, a mirror member, or a sub-mirror with respect to a fixed position due to an increase in the number of times of operation, and to use this position change to detect a focus detection optical system. It is an object of the present invention to provide a camera capable of appropriately correcting a shift between a focus position and a focus position on an image plane even if the optical path length of the camera changes, and performing highly accurate focus detection.

A second object of the present invention is to provide a camera capable of performing highly accurate focus adjustment.

A third object of the present invention is to make it possible to calculate focus information in many focus detection areas without largely occupying an effective range used for focus detection of an optical member, a mirror member, or a sub-mirror. It is intended to provide a camera that does.

A fourth object of the present invention is to provide a camera capable of detecting a predetermined image by the light receiving means with higher accuracy.

[0019]

According to a first aspect of the present invention, there is provided a light-receiving means comprising a plurality of photoelectric conversion elements, and a light-receiving optical path from outside the light-receiving optical path when focus is detected. Within the effective range of the optical member, which is used to guide the light flux to the light receiving means. An image forming unit that forms a predetermined image on the light receiving unit by the incidence of the light beam, and based on a light amount distribution related to the predetermined image on the light receiving unit, the optical member with respect to the fixed position. The camera is provided with a calculation means for calculating a position change.

Similarly, in order to achieve the first object,
According to a second aspect of the present invention, there is provided a light receiving unit including a plurality of photoelectric conversion elements, and a light beam that has been moved from outside the photographing optical path to a fixed position in the photographing optical path during focus detection and has passed through a photographing lens. The optical member forms an image on the light receiving unit by entering the light beam within an effective range of the optical member used for guiding the light beam to the light receiving unit. An image forming unit is provided, and a position change of the optical member with respect to the fixed position is calculated based on each output output from the plurality of photoelectric conversion elements constituting the light receiving unit when the predetermined image is formed. This is a camera provided with a calculating means for performing the operation.

Similarly, in order to achieve the first object,
According to a third aspect of the present invention, there is provided a light receiving means comprising a plurality of photoelectric conversion elements, and a light flux which has been moved from outside the photographing optical path to a fixed position in the photographing optical path during focus detection and has passed through a photographing lens. A mirror member for guiding the light beam to the light receiving unit to form a predetermined image on the light receiving unit within an effective range of the mirror member used for guiding the light beam to the light receiving unit. An image forming unit is provided, and a position change of the mirror member with respect to the fixed position is calculated based on each output output from the plurality of photoelectric conversion elements constituting the light receiving unit when the predetermined image is formed. This is a camera provided with a calculating means for performing the operation.

Similarly, in order to achieve the first object,
According to a fourth aspect of the present invention, the light receiving means including a plurality of pairs of photoelectric conversion elements, and at the time of focus detection, moving from a position outside the photographing optical path to a fixed position in the photographing optical path, and passing the light flux passing through the photographing lens. And a sub-mirror for guiding the light beam on the light-receiving means. In a camera for detecting focus information by a phase difference method, the light beam enters the effective range of the sub-mirror used to guide the light beam to the light-receiving means. An image forming unit that forms a predetermined image on the light receiving unit is provided, and based on each output output from the plurality of photoelectric conversion elements constituting the light receiving unit by forming the predetermined image, The camera is provided with arithmetic means for calculating a change in position of the sub-mirror with respect to the fixed position.

In order to achieve the second object,
According to a seventh aspect of the present invention, there is provided the camera according to the sixth aspect, further comprising a focus adjustment unit that converts focus information obtained by the focus detection unit into a drive amount of the photographing lens and performs focus adjustment. .

In order to achieve the third object,
An eleventh aspect of the present invention is the camera according to the first or second aspect, wherein at least one image forming unit is provided near an end of the optical member.

Similarly, in order to achieve the third object,
According to a twelfth aspect of the present invention, at least one image forming unit is provided near an end of the mirror member.
Described above.

Similarly, in order to achieve the third object,
According to a thirteenth aspect of the present invention, at least one image forming unit is provided near an end of the sub mirror.
Described above.

In order to achieve the fourth object,
According to a fourteenth aspect of the present invention, there is provided the camera according to any one of the first to fourth aspects, wherein the image forming unit has a linear shape.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments.

(First Embodiment) FIG. 1 is a configuration diagram showing a main part of a camera according to each embodiment of the present invention. Portions having the same functions as those in FIG. The details are omitted.

In FIG. 1, a part of a light beam that has passed through a photographing lens 101 is reflected upward in the figure by a main mirror 103 having a semi-transmissive part, and a finder optical system including a focus plate 104, a pentaprism 105, and an eyepiece lens 106. Guided to the system. On the other hand, the remaining light beam that has passed through the semi-transmissive portion of the main mirror 103 is reflected downward by a sub-mirror 107 in the figure, and the focus detection device 1 adopting a known phase difference method.
08.

The light beam reflected downward by the sub-mirror 107 in the figure once forms an image on the image forming surface of the photographing lens 101, that is, on the primary image forming surface 102a having an optically conjugate positional relationship with the image recording medium 102. , Visual field mask 1, photographing lens 1
After passing through the field lens 115 for forming an image of the pupil 101b of the secondary imaging lens and the entrance pupil of the secondary imaging lens, the optical path is changed by the total reflection mirror 2 to the left in the figure. Thereafter, a pair of subject images are formed on the image sensor 118 composed of a pair of photoelectric conversion element arrays via the infrared cut glass 3, the stop 116 having a pair of openings, and the secondary imaging lens 117 having a pair of exit surfaces. are doing.

The main mirror 103 is provided so as to be rotatable about a main mirror rotating shaft 103a. The main mirror 103 is stationary at the position shown in FIG. 1 at the time of focus detection, and retreats outside the photographing optical path at the time of photographing. It is constituted by a quick return mechanism. The same applies to the sub mirror 107.
In addition, the entrance surface of the secondary imaging lens 117 has a concave shape so that the light beam is not forcibly refracted, and a good image without distortion over a wide range on the image sensor 118 can be obtained.

As shown in FIG. 2, the image sensor 118 is composed of a pair of photoelectric conversion element arrays formed of a plurality of photoelectric conversion elements, and includes a pair of emission surfaces corresponding to a pair of emission surfaces of the secondary imaging lens 117. The photoelectric conversion element rows 4a, 4b and 5a,
5b and 6a, 6b are formed. The pair of photoelectric conversion element arrays 4a, 4b and 5a, 5b and 6a, 6b detect the light amount distribution of the pair of subject images,
A focus adjustment state of the photographing lens 101 is detected by well-known phase difference focus detection.

In the figure, only the photoelectric conversion element rows 4a and 4b have photoelectric conversion elements for each pixel, but the other photoelectric conversion element rows 5a, 5b, 6a and 6b are similarly configured. The pair of photoelectric conversion element rows 4a and 4b are divided into regions as shown in the drawing, but the other photoelectric conversion element rows 5a, 5b, 6a and 6b are similarly divided. I have.

FIG. 3 shows a pair of photoelectric conversion element arrays 4a, 4b and 5a, 5b and 6a, 6 on the image sensor 118.
b is projected back onto the image recording medium 102, and the photographing lens 10
FIG. 2 is a view as viewed from the first side. On the image recording medium 102, a pair of photoelectric conversion element rows 4a, 4b and 5a, 5b, and 6
a and 6b almost coincide with each other and overlap each other.
5 and 6 are shown. In FIG. 3, 7a,
Reference numerals 7b, 7c, 7d, and 7e depict focus detection frames (not shown) displayed in the viewfinder onto the image recording medium 102.

Here, a pair of photoelectric conversion element arrays 4a, 4
b, 5a, 5b, 6a, and 6b are each divided into regions as described above. Therefore, the back-projected photoelectric conversion element arrays 4, 5, and 6 also include the photoelectric conversion element arrays 4a, 4b, and 4b. The divided regions 5a, 5b, 6a, and 6b are divided into three portions, and each divided region forms one focus detection region. A focus detection frame is provided corresponding to this focus detection area.
When back-projected onto 2, as shown in FIG. 3, 7a, 7b, 7c, 7d, and 7e are located at positions corresponding to the focus detection areas.

With the above configuration, the image recording medium 102
By adjusting the target subject to the focus detection frame in the viewfinder corresponding to 7a, 7b, 7c, 7d, 7e above, it is possible to detect the focus adjustment state of the taking lens. In the divided focus detection areas of the focus detection areas 4, 5, and 6, the areas in the photoelectric conversion element arrays 4a, 4b, 6a, and 6b corresponding to the focus detection areas indicated by dotted lines in FIG. , Are not used for focus detection in the present embodiment.

FIG. 4 is a front view of the reflecting surface of the sub mirror 107 shown in FIG.

On the reflection surface side of the sub-mirror 107, patterns 8a and 8b are provided by means such as printing as shown in the figure, and a black low-reflection paint or the like is used to reduce the reflectance as much as possible. It is composed of Therefore, the subject image formed on the image sensor 118 is
This is a light beam reflected by the area on the sub-mirror 107 excluding the patterns 8a and 8b. The patterns 8a and 8b are a pair of photoelectric conversion element rows 4a and 4 of the image sensor 118.
It is provided at a position on the submirror 107 corresponding to the region so that it can be detected in the regions b, 6a, and 6b.

With the above-described configuration, even if the stationary position at the time of focus detection of the sub-mirror 107 movably provided during photographing changes due to an increase in the number of times of integration operation, the sub-mirror 107 remains on the sub-mirror 107. Pattern 8 provided
By using the detection results a and 8b by the image sensor 118, it is possible to correct the deviation of the focus detection signal, and it is possible to perform the focus detection with high accuracy.

Then, first, the image sensor 1
The detection of the patterns 8a and 8b by the method 18 will be described.

FIG. 5 is a diagram in which the patterns 8a and 8b on the sub-mirror 107 are projected on the image sensor 118 of FIG. 2 in the initial state where the rest position of the sub-mirror 107 has not changed.

A pair of photoelectric conversion element arrays 4a, 4b and 6
A pair of pattern images 9a, 9b and 9c, 9d indicated by oblique lines in the figure corresponding to the patterns 8a, 8b are formed at predetermined intervals on the regions a, 6b. In fact,
Since the reflectance of the patterns 8a and 8b on the sub-mirror 107 is extremely low, no image is formed on the image sensor 118. However, in order to make the area on the image sensor 118 corresponding to the patterns 8a and 8b easy to understand, a hatched area As shown. In addition, the actual image sensor 11
The image formed on 8 is a pair of photoelectric conversion element rows 4a and 4b.
1 and 5a, 5b and 6a and 6b, and the other areas are restricted by the field mask 1 of FIG.

FIG. 6 shows the photoelectric conversion element array 4 shown in FIG.
FIG. 6 is an enlarged view of a main portion in which the vicinity of the pattern images 9a and 9b of FIGS. 5a and 5b is enlarged, and the focus of the taking lens 101 is formed on the image recording medium 102 as in FIG.

In the figure, reference numerals 10a and 10b denote image signals output from the photoelectric conversion element arrays 4a and 4b based on the light quantity distribution relating to the pattern image, and Z ₀ denotes a known image interval detection process from the image signals 10a and 10b. The resulting image spacings are each shown. Since the pattern 8a on the sub-mirror 107 is separated from the primary imaging plane 102, the actual image sensor 11
The pair of pattern images 9a and 9b formed on the image 8 are blurred images. Therefore, for example, the photoelectric conversion element arrays 4a, 4b
When an object having uniform and appropriate luminance is detected in the region of, the output image signal draws a curve with a slightly gentle fall as shown by 10a and 10b.

Further, the positions where the pattern images 9a and 9b are formed on the image sensor 118 are slightly shifted from the optically conjugate positions. However, the photoelectric conversion element array 4
When a subject having a substantially uniform and appropriate luminance is detected in the areas a and 4b, the image signal output from the image sensor 118 is a flat high-luminance part (peak part) as shown in 10a and 10b in FIG. ) And a flat low-luminance portion (bottom portion) are noticeable, and if the image interval between the pattern images 9a and 9b is Z ₀ , the image interval Z ₀ can be detected using a known image interval detection process. It is. This image interval Z ₀ is the image interval in the initial state where the rest position of the sub mirror 107 has not changed. The pattern image 9a, the image signal 10a regarding 9b, by removing the noise component hosting the arithmetic filtering 10b, it is possible to accurately detect the image distance Z ₀ even somewhat uneven object.

The pattern 8a on the sub mirror 107
Is located between the taking lens and the primary imaging plane 102a, so that the focusing state of the taking lens 101 (defocus)
And the image interval Z ₀ is always constant regardless of the focus adjustment state. That is, the image interval Z ₀
Depends on the position change between the subject and the optical member.

Next, a case where the rest position changes due to an increase in the number of operations of the sub mirror 107 will be described.

FIG. 7 is an enlarged view of a main part in which a portion centering on the sub-mirror 107 in FIG. 1 is enlarged. Parts denoted by the same reference numerals as those in FIG. Is omitted.

When the number of times of operation of the main mirror 103 and the sub-mirror 107, which are operated in accordance with the photographing operation of the camera, increases, the rest positions of the main mirror 103 and the sub-mirror 107 change due to wear and fatigue of the members constituting these operating mechanisms. .

Thus, for example, as shown in FIG. 7, consider the case where the rest position of the sub-mirror 107 changes as indicated by a dotted line 107 'around the sub-mirror rotation axis 107a. Note that the change in the rest position due to the number of times the main mirror 104 is integrated has a smaller effect on the focus detection device 108 than that of the sub-mirror 107, and will not be described.

When the rest position of the sub-mirror 107 does not change, that is, in the initial state, the optical axis 101a of the taking lens 101 passes through the main mirror 103 and then moves to the sub-mirror 1
The optical axis 101c changes its direction downward in the figure by 07, and is guided to the focus detection device 108. On the other hand, when the rest position of the sub-mirror 107 changes and becomes as indicated by a dotted line 107 ′ in the figure, the optical path of the optical axis 101 a of the photographing lens 101 is changed by the sub-mirror 107 ′ after passing through the main mirror 103. '. Accordingly, the primary imaging plane 102a also tilts while shifting to the right and upward in the figure as indicated by a dotted line 102a 'in the figure.

FIG. 8 is an enlarged view of a main part similar to FIG.
FIG. 8 is a diagram in which a pattern 6 is projected onto an image sensor 118 when the sub mirror 107 is displaced to a stationary position of 107 ′ in FIG. As in FIGS. 5 and 6, the focal point of the photographing lens 101 is imaged on the image recording medium 102. In the drawings, portions denoted by the same reference numerals as those in the above-described drawings are portions having the same functions, and details thereof will be omitted.

As shown in FIG. 7, the primary imaging plane 10
2a becomes 102a ', and the primary imaging surface is
1 and the optical path length from the primary imaging plane to the image sensor 118 becomes longer, so that the pair of pattern images 9a and 9
b moves in the direction in which the image interval decreases, and becomes 9a 'and 9b' indicated by the dotted lines in FIG. Strictly speaking, the amount of movement of each of the pair of pattern images 10a and 10b is different. Accordingly, the image signal 1 by the image sensor 118
0a, 10b are also 10a ', 10b indicated by dotted lines in the figure.
b ′, and the image interval Z ₁ after the change of the sub-mirror 107 stationary position is calculated by a known image interval detection process.

Here, the image interval Z in the initial state₀ And Submira
-107 Image interval Z after change in rest position ₁ From the following formula
According to (1), the image interval deviation amount ΔZ₁ Is calculated.

ΔZ ₁ = Z ₁ −Z ₀ (1) By reflecting the image interval shift amount ΔZ ₁ on the focus adjustment amount of the photographing lens 101, the difference is high even when the rest position of the sub-mirror 107 changes. Accurate focus detection can be realized.

The pattern 8a on the sub-mirror 107 has been described above, but the same applies to the pattern 8b.

Next, the actual operation related to the correction of the focus detection signal will be described.

FIG. 9 is a block diagram showing a circuit configuration of a camera according to the present embodiment, and portions having the same functions as those in the above-mentioned respective drawings are denoted by the same reference numerals.

The image sensor 118 has a focus detection circuit 1
The focus detection circuit 110 is connected to a microcomputer 109 serving as a processing device, and specifies a light receiving area of the image sensor 118 and controls accumulation of photocharges. The microcomputer 109 has a CP
U (central processing unit) 109a, ROM 109b, RAM1
09c, an EEPROM (electrically erasable programmable ROM) 109d, and executes a focus detection operation according to a program stored in the ROM 109b.

In the EEPROM 109d, optical information of the focus detection optical system and the like are stored in advance during the adjustment process. Further, a switch SW1 which is turned on by a first stroke of a release button operated by a photographer and a switch SW2 which is turned on by a second stroke are connected to the microcomputer 109. Further, a mirror driving circuit 112 for driving a mirror driving unit 111 for retracting the main mirror 103 and the sub-mirror 107 outside the photographing optical path at the time of photographing, and a lens for adjusting and moving a focus lens array (not shown) of the photographing lens 101 according to a focus detection state. Lens driving circuit 114 for driving the driving means 113
Are connected to the microcomputer 109, respectively.

Next, the operation of the microcomputer 109 which proceeds according to the focus detection processing program stored in the ROM 109b will be described with reference to the flowchart of FIG.

First, in step # 101, the release button is operated by the photographer and the hand switch SW1 is turned on.
It is determined whether or not N has been performed, and when it is turned on, step # 10 is performed.
Proceed to 2. Then, in step # 102, photocharge accumulation is started in each region of the image sensor 118 corresponding to at least one focus detection frame (not shown) selected in advance, and the accumulated charges are read out as a pair of image signals. , In the RAM 109c. Next step # 1
In step 03, the reliability of the image signal is determined. If the reliability does not satisfy the predetermined condition, it is determined that the focus cannot be detected, and the process proceeds to step # 104.

On the other hand, if the reliability of the focus detection signal satisfies the predetermined condition, the process proceeds from step # 103 to step # 1.
Proceeding to step 05, after performing a correction on the pair of image signals by the aberration of the focus detection optical system, a digital filter calculation process for removing a specific frequency component is executed. And the next step #
In 106, a known image interval detection process is performed on the pair of image signals to calculate an image shift amount from the image interval at the time of focusing and the current image interval. Note that the image interval at the time of focusing is shown in FIG.
Is different for each focus detection area described above, and the image interval at the time of focusing in each focus detection area is determined in advance by the EEPROM 109.
d. Thereafter, various corrections such as correction of the image interval based on the temperature are performed, and the focus adjustment amount of the photographing lens 101 in the focus detection frame selected previously is calculated.

Next, in step # 107, the drive amount of a focus lens (not shown) of the photographing lens 101 is calculated from the calculated focus adjustment amount, and the lens drive device 113 is driven by the drive amount calculated via the lens drive circuit 114. It drives and adjusts the focus of the photographing lens 101. Then, in the next step # 108, it is determined whether or not the focus adjustment state after driving the lens is within the focusing range, and if it is determined that the focus adjustment state is within the focusing range, the process proceeds to step # 109. If it is determined that it is not within the focus range, the process returns to the focus detection process of step # 102.

When the process proceeds to step # 109, here, FIG.
A pair of photoelectric conversion element rows 4a, 4b and 6 of the image sensor 118 onto which the patterns 8a and 8b shown in FIG.
The photocharges accumulated in the areas a and 6b are read out as a pair of image signals and stored in the RAM 109. Here, two pairs of image signals relating to the patterns 8a and 8b are stored. Then, in the next step # 110, the reliability of the pair of image signals is determined, and the reliability of one or both of the two pair of image signals satisfies a predetermined condition. If it is determined that the reliability does not satisfy the predetermined condition, the process immediately proceeds to step # 116,
The pattern detection processing ends.

Here, the method of determining reliability is shown in FIG.
As described above, the image signals relating to the patterns 8a and 8b in the case where a subject having uniform and appropriate luminance is detected are stored in the EEPROM 109d in advance during the manufacturing process, and this image signal and the image signal at the time of pattern detection are stored. A method such as determination based on the amount of correlation can be considered.

If it is determined that the reliability of the image signal satisfies the predetermined condition and the process proceeds to step # 111, a digital filter for removing a specific frequency component after correcting a pair of image signals by the aberration of the focus detection optical system. Perform arithmetic processing. Then, in the next step # 112, first, a known image interval detection process is performed on a pair of image signals whose reliability is determined to satisfy the predetermined condition, and an image interval is calculated. Next, from the image interval in the initial state stored in the EEPROM 109d in advance in the manufacturing process, the image interval shift amount is calculated by the above equation (1), and at the same time, the integrated detection count is calculated. Here, the total number of times of detection is the above-mentioned step # 110.
1 if the predetermined condition is satisfied in the reliability judgment in
Means the number of integrations up to the present, and is rewritten to a value increased by one when passing the next step # 112.

Here, assuming that the image interval shift amount due to the pattern 8a when the number of times of integration detection is n is ΔZ _an and the image interval shift amount due to the pattern 8b is ΔZ _bn , the representative image interval shift amount is given by the following equation (2). ΔZ _n is calculated.

ΔZ _n = (ΔZ _an + ΔZ _bn ) / 2 (2) However, depending on the result of the reliability determination in step # 110, the image interval deviation amount ΔZ _an or the image interval deviation amount ΔZ _bn
If only one of them has not been calculated for, regardless of the above formula (2), the image interval shift amount of the person which is calculated as the representative image interval deviation amount [Delta] Z _n.

In the next step # 113, the representative image interval deviation amount ΔZ _n and the integrated detection number n at that time are stored in the EEP.
It is stored in the ROM 109d. And the next step # 1
At 14, it is determined whether or not the integrated detection count n is equal to or greater than a threshold value m. If it is equal to or greater than the threshold value m, the flow proceeds to the correction amount calculation in step # 115. Here, the reason why the threshold value m is provided in this way is that the sub-mirror 107 has a slight variation in the rest position for each operation,
This is because a high-accuracy focus detection can be realized by removing the influence due to the variation of the pattern detection signal due to the subject, and performing correction using a plurality of pattern detection results. In addition, when the integrated number of detections n is extremely small compared to the increase in the number of times of operation of the sub-mirror 107 and is unlikely to reach the threshold value m, the value of the threshold value m is changed according to the number of times of operation of the sub-mirror 107. It is desirable that the correction be performed at an appropriate timing.

When the process proceeds to step # 115, here, a plurality of representative image interval deviation amounts ΔZ ₁ , ΔZ ₂ ,... Stored in the EEPROM 109d in step # 113.
Calculate the image spacing correction amount from ΔZ _m , multiply this image spacing correction amount by a coefficient corresponding to each focus detection area, and calculate the image spacing correction amount for each focus detection area. Therefore, assuming that the image interval correction amount is ΔZ _C and, for example, the coefficient in the focus detection area corresponding to the focus detection frame 7a in FIG. 3 is C _FP1 , the image interval correction amount per focus detection area ΔZ _FP1C is _expressed by the following equation ( It is calculated by 3).

ΔZ _FP1C = C _FP1 × ΔZ _C (3) On the basis of the correction amount ΔZ _FP1C for each focus detection area,
The image interval at the time of focusing in the initial state, which is stored in advance in the EEPROM 109d, is corrected, and the integrated detection number n stored in step # 113 is reset to zero.

Now, _assuming that the image interval at the time of initial focusing in the focus detection area corresponding to the focus detection frame 7a is _ZFP1 ,
The image interval Z _FP1 is rewritten according to the following equation (4),
From the next focus detection, the deviation of the image interval due to the change in the stationary position of the sub mirror 107 is corrected.

Z _FP1 = Z _FP1 + ΔZ _FP1C (4) Similarly, the deviation of the image interval is corrected in the focus detection areas corresponding to the other focus detection frames 7b to 7e.

The coefficient C _FP1 corresponding to the focus detection area
Is a constant that is experimentally measured to measure a change in the stationary position with an increase in the number of operations of the submirror 107, and is estimated from the experimental result, and is predetermined. Therefore, the correction of the image interval shift due to the change in the rest position of the sub mirror 107 is performed every m detection times (m is a threshold value). Here, the coefficient corresponding to the focus detection area on the image interval correction amount [Delta] Z _C C
_As shown in FIG. 7, the multiplication by the _FP is performed by the sub-mirror 107.
Is assumed to change around the sub-mirror rotation axis 107a, the change in the optical path length of the focus detection optical system differs depending on the light beam reflection position on the sub-mirror 107.

Then, the process proceeds to a step # 116, wherein it is determined whether or not the switch SW2 which is turned on by the second stroke of the release button is operated by the photographer.
If the switch SW2 is ON, the process proceeds to step # 117, and if not, the process waits at this step. Thereafter, when the switch SW2 is turned on, step # 117 is performed.
The main mirror 103 and the sub-mirror 107 are retracted out of the photographing optical path by driving the mirror driving means 111 via the mirror driving circuit 112, and the photographing operation is performed by opening and closing a shutter (not shown).

As described above, according to the first embodiment, the number of actuations of the sub-mirror 107 is increased, and the wear of the rotation support member and the member for regulating the rest position is reduced.
Even if the rest position of the sub-mirror 107 changes and the focus position of the photographing lens 101 and the focus position obtained by the focus detection calculation deviate due to a change in the optical path length of the focus detection optical system, the patterns 8a, 8b, 8b, it is possible to correct the focus detection result according to the detection result, thereby realizing high-precision focus detection that is not affected by the number of operations of the optical members constituting the focus detection optical system. can do. Also, the patterns 8a,
By performing the detection of 8b after the focusing of the taking lens 101,
There is no reduction in focusing speed.

The image shift direction of the pattern images 9a to 9d on the image sensor 118 due to the change of the stationary position of the sub mirror 107 in the rotation direction about the sub mirror rotation axis 107a, and the image sensor 118 by the phase difference method
Image shift direction above (pupil 10 of photographing lens due to aperture 16)
1b), and the change in the stationary position in the rotation direction is detected efficiently. However, the two image shift directions are orthogonal to each other, that is, the division of the pupil 101b of the photographing lens is the left and right direction. The present invention can be applied even in the case (in the direction perpendicular to the plane of FIG. 1).

Further, the description has been made using the phase difference type focus detection apparatus. However, the present invention can be applied to a contrast (blur) detection type focus detection apparatus. In this case, an image shift from an initial state due to a pattern is detected. The focus detection result may be corrected in accordance with the detection result. Specifically, the contrast detection method is equivalent to a case where only one side of the pair of photoelectric conversion element rows in the above-described phase difference method is provided. In this case, the absolute position of the image based on the pattern in the initial stage on the image sensor (where the image is located on the plurality of photoelectric conversion elements) is stored, and the absolute position of the image based on the pattern over time is detected. Correction is performed based on the absolute position change amount from the initial state.

(Second Embodiment) Hereinafter, a second embodiment of the present invention will be described. The second embodiment is different from the first embodiment in that the sub-mirror 10
7 is an improvement of the number, position, and shape of the patterns provided on the sub-mirror 7, and correction of the image interval deviation due to a change in the stationary position of the sub-mirror 107. Other portions are the same as those in the first embodiment. The description thereof will be omitted, and the drawings and reference numerals used in the first embodiment will be used as needed.

FIG. 11 shows the sub mirror 10 shown in FIG.
7 is a plan view of the anti-slope side of the sub-mirror 107 seen from the photographing lens side, and near the four corners on the anti-slope side of the sub-mirror 107, as shown in the figure, patterns 11a, 11b, 11c,
11d is provided by means such as printing.

FIG. 12 shows patterns 11a-1 on the sub-mirror 107 on the image sensor 118 in FIG. 2 in the initial state where the rest position of the sub-mirror 107 has not changed.
FIG. 1D is a projected image of FIG.
2a, 12b, 12c, 12d, 12e, 12f, 12
g, 12h.

The pattern images 12a to 12h are formed on and above the areas of the photoelectric conversion element arrays 4a, 4b, 6a, 6b that are not used for focus detection in the image sensor 118. The pattern 11a and the pair of pattern images 1
2a and 12c are a pattern 11b and a pair of pattern images 1
2b and 12d are a pattern 11c and a pair of pattern images 1
2e and 12g are a pattern 11d and a pattern image 12f,
12h is an image corresponding to each pattern.

FIG. 13 is an enlarged view of a main part of the photoelectric conversion element rows 4a and 4b shown in FIG.
a, 13b, 13c, 13d are photoelectric conversion element rows 4a, 4
a pattern image signal output from the b, ZB1 ₀ is the image signal 13a, the image interval obtained through known image interval detection process than 13c, similarly ZB2 ₀ is the image signal 13b, and image interval by 13d, respectively Each is shown.

Here, similarly to the first embodiment,
The pattern 11 on the sub-mirror 107 is the primary image plane 102
a, the pair of pattern images 12 a to 12 d actually formed on the image sensor 118 become blurred images, and
The positions where a to 12d are formed also slightly deviate from the optically conjugate positions. However, when a subject having an appropriate and uniform luminance is detected, the image intervals ZBa ₀ and ZBb ₀ can be calculated by the image interval detection processing. Further, in the present embodiment, the pattern on the sub-mirror 107 has a single linear shape, and the pattern image signal has one high-luminance portion (peak portion) and two flat low-luminance portions. The image interval can be detected with higher accuracy than the first embodiment. In the photoelectric conversion element arrays 6a and 6b, the image interval is calculated based on the same principle. Further, the case where the rest position of the sub-mirror 107 changes is the same as in the first embodiment.

The actual operation of the camera relating to focus detection and pattern detection is the same as that of the first embodiment described above, and therefore description thereof is omitted, and here, the image interval due to a change in the stationary position of the sub mirror 107 is described. The part related to the change correction will be described.

First, patterns 11a, 11b, 11c,
O, p, q, r
And the image gap image shift amounts at that time calculated by the equation (1) in the first embodiment are ΔZ _ao , ΔZ _bp , Δ
Z _cq and ΔZ _dr . At this time, the integrated detection times o, p,
The minimum of q and r is defined as the total number of detections n, and EEP
It is stored in the ROM 109d. At the same time, the image interval shift amounts ΔZ _ao , ΔZ _bp , ΔZ _cq , and ΔZ _dr for each pattern are stored in the EEPROM 109d.

Next, when the integrated detection number n reaches the threshold value m, the image interval is corrected in the same manner as in the first embodiment.

First, a plurality of image interval deviation amounts ΔZ _a1 , ΔZ _a2 ,..., ΔZ _am for the pattern 11a are used, and the image interval correction amounts for the pattern 11a calculated based on these are ΔZ _aC and ΔZ _aC . Then, the EEPROM 109
a plurality of image interval shift amounts ΔZ _a1 , Δ stored in d.
Based on Z _a2 ,..., ΔZ _am , the image interval correction amount ΔZ
Calculate _aC . Similarly, patterns 11b, 11c, 11
The image spacing correction amounts for d are ΔZ _bC , ΔZ _cC , Δ
_Assuming that Z _dC , the image interval correction amount ΔZ _bC ,
ΔZ _cC and ΔZ _dC are calculated.

Next, the calculation of the image spacing correction amount for each focus detection area will be described.

In FIG. 12, focusing on the photoelectric conversion element rows 4a, 5a and 6a on the upper side in the figure among the pair of photoelectric conversion element rows, the patterns 11a to 11d on the sub-mirror 107 are shown.
The pattern images 12a, 12b, 12e, and 12f by
The upper photoelectric conversion element rows 4a, 5a, and 6a are formed in four corner areas. Therefore, it is possible to interpolate and calculate the image shift amount in the region between them, that is, the region used for focus detection, from the image shift amounts in the four corner regions.

The same applies to the lower photoelectric conversion element rows 4b, 5b, 6b in FIG. 12, and therefore, the image spacing correction amounts ΔZ _aC , ΔZ _bC , ΔZ calculated _earlier .
_{Using cC} and ΔZ _dC , the image spacing correction amount in the five focus detection areas in FIG. 3 can be calculated by interpolation.

More specifically, the focus detection frame 7a in FIG.
Are detected by the patterns 11a and 11b, the focus detection area corresponding to the focus detection frame 7b is determined by the patterns 11a and 11c, and the focus detection area corresponding to the focus detection frame 7a is determined by the patterns 11a and 11b. The focus detection areas corresponding to 7c are patterns 11a,
The focus detection area corresponding to the focus detection frame 7d by the pattern 11b or the pattern 11b,
By 11d, the focus detection area corresponding to the focus detection frame 7e is calculated based on the image interval correction amount by the patterns 11c and 11d.
I will supplement each. Therefore, for example, _assuming that the image spacing correction amount for each focus detection area in the focus detection area corresponding to the focus detection area 7a is _ΔZFP1C , it is assumed that the image spacing correction amount for the light beam passing between the patterns on the sub-mirror 107 is linear. , The image interval correction amount ΔZ _FP1C for each focus detection area is calculated by the following equation (6).

ΔZ _FP1C = (ΔZ _aC + ΔZ _bC ) / 2 (6) Similarly, the image interval correction amount for each focus detection area in the focus detection areas corresponding to the focus detection frames 7b, 7c, 7d, and 7e. each _{ΔZ FP2C, ΔZ FP3C, ΔZ FP4C} , When ΔZ _FP5C, are calculated by the following equation (7) to (10).

ΔZ _FP2C = (ΔZ _aC + ΔZ _cC ) / 2 (7) ΔZ _FP3C = (ΔZ _aC + ΔZ _dC ) / 2... (8) ΔZ _FP4C = (ΔZ _bC + ΔZ _dC ) / 2 ... (9) ΔZ _FP5C = (ΔZ _cC + ΔZ _dC ) / 2 (10) Note that the image spacing correction amount ΔZ for each focus detection area in the above equation (8)
_{The FP3C} may be calculated using the image interval correction amounts ΔZ _bC and ΔZ _{dC, or} may be calculated using both calculation results. By applying the focus detection-specific image interval correction amount to Expression (4) in the first embodiment, it is possible to correct the image interval deviation due to a change in the stationary position of the sub mirror 107 with high accuracy.

As described above, in the second embodiment,
In other words, as shown in the equation (3) of the first embodiment,
In accordance with the focus detection area determined from experimental results
Coefficient _FPNear the four corners of the sub-mirror 107 without using
Based on the detection results of the shifted patterns 11a to 11d
Correction is performed for each focus detection area.
The change in the rest position of the roller 107 has a large individual variation
Even if it does, highly accurate correction can be performed.

Further, since a pattern on a single line is used as the pattern on the sub mirror 107, the first embodiment
As compared with the embodiment, the calculation error in the image interval calculation processing can be reduced. If a two-line pattern having a different width is used, it is possible to further reduce the calculation error.

In the second embodiment, the five focus detection areas are corrected on the basis of the detection results of the four patterns 11a to 11d. However, even if more focus detection areas are provided, By correcting the detection results of the patterns 11a to 11d, correction can be made with high accuracy.
Conversely, by increasing the number of patterns and interpolating a large number of detection results, more accurate correction can be performed.

According to each of the above embodiments, a pattern is provided within the effective range of sub-mirror 107, which is an optical member used to guide a light beam to image sensor 118, and image sensor 118 detects a light amount distribution related to the pattern. With this configuration, even if the relative positional relationship between the sub-mirror 107 and the image sensor 118 changes from the initial state due to an increase in the number of operations of the sub-mirror 107, the image sensor 118 detects the shift in the light amount distribution related to this pattern, The position change can be known.

Further, since the focus adjustment amount (information on focus detection) of the photographing lens 101 is corrected based on the result of detecting the light quantity distribution of the pattern by the image sensor 118, the position of the sub-mirror 107 is not affected. Highly accurate focus detection can be realized.

Further, since at least one pattern is provided in the vicinity of the end of the sub mirror 107, the effective range used for focus detection of the sub mirror 107 is not largely occupied, and the focus detection area is not obstructed. And the light amount distribution related to the pattern can be detected. Further, by performing the correction using the light amount distributions regarding a plurality of patterns, it is possible to detect the focus with higher accuracy.

Further, in the second embodiment, since the shape of the pattern is a linear shape, it is possible to reduce the calculation error due to the image interval processing calculation, and it is possible to detect the pattern image interval with higher accuracy. It is.

[0104]

As described above, claims 1, 2, 3
According to the invention described in the fourth aspect, a change in the position of the optical member, the mirror member, or the sub-mirror with respect to the fixed position due to an increase in the number of operations is calculated, and the optical path length of the focus detection optical system changes due to the change in the position. Also, it is possible to provide a camera capable of appropriately correcting a shift between a focus position and a focus position on an image plane and performing focus detection with high accuracy.

According to the seventh aspect of the present invention, it is possible to provide a camera capable of performing highly accurate focus adjustment.

According to the eleventh, twelfth, and thirteenth aspects of the present invention, the focus can be obtained in many focus detection areas without largely occupying the effective range used for focus detection of the optical member, the mirror member, or the sub-mirror. It is possible to provide a camera capable of calculating information.

According to the fourteenth aspect of the present invention,
An object of the present invention is to provide a camera capable of detecting a predetermined image with a light receiving unit with higher accuracy.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an optical configuration of a camera according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a schematic configuration of a light receiving surface of the image sensor of FIG.

FIG. 3 is a diagram in which a photoelectric conversion element array and a focus detection frame of an image sensor are back-projected on the image recording medium of FIG. 1;

FIG. 4 is a diagram showing a pattern of a sub-mirror anti-slope surface in the first embodiment of the present invention.

5 is a diagram in which the pattern of FIG. 4 is projected on the light receiving surface of the image sensor of FIG.

FIG. 6 is an enlarged view of a main part of the image sensor of FIG. 5;

FIG. 7 is an enlarged view of a main part in which the vicinity of a sub mirror in FIG. 1 is enlarged.

FIG. 8 is an enlarged view of a main part of the image sensor of FIG. 5;

FIG. 9 is a block diagram showing a circuit configuration of the camera according to the first embodiment of the present invention.

FIG. 10 is a flowchart showing an operation of a main part of the camera according to the first embodiment of the present invention.

FIG. 11 is a diagram showing a pattern of a sub-mirror anti-slope surface according to the second embodiment of the present invention.

FIG. 12 is a diagram in which the pattern of FIG. 11 is projected on the light receiving surface of the image sensor according to the second embodiment of the present invention.

FIG. 13 is an enlarged view of a main part of the image sensor of FIG. 12;

FIG. 14 is a schematic diagram showing an optical configuration and a circuit configuration of a conventional camera.

FIG. 15 is a diagram illustrating the principle of a phase difference (image shift) method.

[Explanation of symbols]

 8a, 8b Pattern 101 Photographing lens 103 Main mirror 107 Submirror 109 Microcomputer 110 Focus detection circuit 111 Mirror driving means 112 Mirror driving circuit 117 Secondary imaging lens 118 Image sensor

Claims (16)

[Claims] 1. A light receiving means comprising a plurality of photoelectric conversion elements, and an optical member which is moved from outside the photographing optical path to a fixed position in the photographing optical path at the time of focus detection, and guides a light beam passing through a photographing lens onto the light receiving means. A camera having an image forming unit that forms a predetermined image on the light receiving unit by entering the light beam within an effective range used to guide the light beam to the light receiving unit of the optical member. And a calculating means for calculating a position change of the optical member with respect to the fixed position based on a light quantity distribution of the predetermined image on the light receiving means. 2. A light receiving means comprising a plurality of photoelectric conversion elements, and an optical member which is moved from outside the photographing optical path to a fixed position in the photographing optical path at the time of focus detection, and guides a light beam passing through a photographing lens onto the light receiving means. A camera having an image forming unit that forms a predetermined image on the light receiving unit by entering the light beam within an effective range used to guide the light beam to the light receiving unit of the optical member. Calculating means for calculating a position change of the optical member with respect to the fixed position based on each output outputted from the plurality of photoelectric conversion elements constituting the light receiving means by forming the predetermined image. A camera characterized by being provided. 3. A light receiving means comprising a plurality of photoelectric conversion elements, and a mirror member which is moved from outside the photographing optical path to a fixed position in the photographing optical path at the time of focus detection, and guides a light beam passing through the photographing lens onto the light receiving means. An image forming unit that forms a predetermined image on the light receiving unit by entering the light beam within an effective range used to guide the light beam to the light receiving unit of the mirror member. Calculating means for calculating a position change of the mirror member with respect to the fixed position based on each output outputted from the plurality of photoelectric conversion elements constituting the light receiving means when the predetermined image is formed. A camera characterized by being provided. 4. A light receiving means comprising a plurality of pairs of photoelectric conversion elements, and at the time of focus detection, a light beam which has been moved from outside the photographing optical path to a fixed position in the photographing optical path, and has passed through a photographing lens. A focusing mirror that detects focus information by a phase difference method, wherein the light beam enters the effective range of the sub-mirror which is used to guide the light beam to the light receiving device. And an image forming unit for forming a predetermined image, and based on each output output from the plurality of photoelectric conversion elements constituting the light receiving means when the predetermined image is formed, the constant of the sub-mirror is determined. A camera characterized by comprising a calculating means for calculating a position change with respect to a position. 5. The method according to claim 1, wherein the predetermined image is formed as a paired image on a pair of photoelectric conversion elements of the plurality of photoelectric conversion elements. Camera described in Crab. 6. Focus information is calculated using outputs of a plurality of photoelectric conversion elements other than the plurality of photoelectric conversion elements on which the predetermined image is formed, which constitutes the light receiving means. The camera according to any one of claims 1 to 5, further comprising a focus detection unit that performs correction based on information on a position change obtained by the calculation unit and calculates final focus information. 7. The camera according to claim 6, further comprising a focus adjustment unit that converts focus information obtained by the focus detection unit into a drive amount of the photographing lens and performs focus adjustment. 8. The calculation means obtains a difference between an image interval forming the pair obtained when the camera is used and an image interval stored in advance, and, based on the information on the difference, information on the position change. The camera according to claim 5, wherein is calculated. 9. The camera according to claim 8, wherein the calculating means calculates the position change information by obtaining the difference information a predetermined number of times. 10. The camera according to claim 9, wherein the number of times is added when the reliability of a photoelectric conversion signal of the paired image satisfies a predetermined condition. 11. The camera according to claim 1, wherein at least one image forming unit is provided near an end of the optical member. 12. The camera according to claim 3, wherein at least one image forming unit is provided near an end of the mirror member. 13. The camera according to claim 4, wherein at least one image forming unit is provided near an end of the sub-mirror. 14. The camera according to claim 1, wherein the shape of the image forming unit is a linear shape. 15. The camera according to claim 5, wherein an arrangement direction of a pair of images formed by the image forming unit is the same as an arrangement direction of the pair of photoelectric conversion elements. 16. The image forming apparatus according to claim 5, wherein the arrangement direction of the paired images formed by the image forming unit and the arrangement direction of the paired photoelectric conversion elements are orthogonal to each other. camera.