JP2002214518A - Single lens reflex camera and finder equipped with focus detection sensor having function to decide necessity of calibration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single lens reflex camera equipped with an interchangeable type finder capable of performing calibration for accurately detecting the amount of out-of-focus without forgetting it, and displaying whether or not the calibration should be performed. SOLUTION: This single lens reflex camera has a camera body having a focusing screen provided with a reference mark corresponding to the position of film, the finder detachably attached to the camera body, a focus detection means which is arranged in the finder and detects a focal position, a deviation detection means which is arranged in the finder and detects the deviation of the focal position from the reference mark, a calibration means for correcting data on the focal position based on output from the deviation detection means, a storage part for storing correction amount calculated by the calibration means, an attachment/detachment detection means for detecting the attachment/ detachment of the finder, and a calibration deciding part for deciding whether or not the calibration is required based on information acquired by the attachment/detachment detection means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a single-lens reflex camera and a finder provided with a focus detection sensor having a calibration function.

[0002]

2. Description of the Related Art In a conventional single-lens reflex camera, a focus detection sensor for detecting a focus of an image of a subject is almost always provided below a main mirror in a camera body. Therefore, single-lens reflex cameras in which a focus detection sensor is provided at a position subsequent to the reticle are not commonly used. For example, Japanese Patent Application Laid-Open No. 2000-75344 discloses a single-lens reflex camera in which a focus detection sensor is provided below a main mirror in a camera body.

[0003]

However, in a conventional single-lens reflex camera in which the focus detection sensor is provided below the main mirror in the camera body, a space for installing the focus detection sensor is provided below the main mirror. Therefore, there is a problem that it is difficult to reduce the size of the camera body. Also, if a focus detection sensor is installed after the focusing screen of the replaceable viewfinder, to reduce the deterioration in the focus detection accuracy of the image of the subject caused by the variation in the combination between the replaceable viewfinder and the individual camera body. In addition, it is necessary to make the mounting accuracy of the replaceable finder and the mounting position of the focus detection sensor extremely high. In addition, the replaceable viewfinder is large in size, so the optical path length from the camera body to the focus detection sensor tends to change due to thermal expansion of optical and metal parts, and it is very important to keep the focus detection accuracy of the image of the subject high. Will be difficult.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a single-lens reflex camera having an exchangeable finder so that a focus detection sensor can be arranged in the finder to detect the focus of an image of a subject with high accuracy. That is, the amount of deviation (defocus amount or defocus amount) between the imaging plane (subject image plane) of the photographing lens and the film equivalent plane is detected with high accuracy. Is to be able to do that. Further, a second object of the present invention is to provide a replaceable type capable of displaying whether or not calibration is necessary without forgetting to carry out calibration for detecting the amount of defocus with high accuracy. An object of the present invention is to provide a single-lens reflex camera provided with a finder.

[0005]

In order to solve the above-mentioned problems, the present invention provides a camera body having a reticle provided with a reference mark corresponding to a film position, and a finder removably attached to the camera body. A focus detection means arranged in the viewfinder to detect a focus position; a shift amount detection means arranged in the viewfinder to detect a shift amount between the reference mark and the focus position; and an output of the shift amount detection means. A calibration unit that corrects the data of the focal position based on the correction amount, a storage unit for storing the correction amount calculated by the calibration unit, an attachment / detachment detection unit for detecting attachment / detachment of the finder, and an attachment / detachment unit. A calibration judging unit for judging whether or not calibration is necessary based on the obtained information. To provide a single-lens reflex camera which is characterized in Rukoto.

In this configuration, the image of the reference mark provided on the focusing screen of the camera body is detected by the focus detection sensor.
The calibration means calculates an error in the optical path length from the reticle to the focus detection sensor based on the detection result of the focus detection sensor, and corrects the error. This allows
An error due to a variation in the optical path length from the reticle to the focus detection sensor can be corrected, and the detection accuracy of the defocus amount can be improved. This correction amount is stored in the storage unit, and is used at the time of a later photographing. The single-lens reflex camera further has an attachment / detachment detection unit for detecting attachment / detachment of the viewfinder, and a calibration determination unit for judging the necessity of calibration based on information detected by the attachment / detachment detection unit. For example, the necessity of calibration is determined at a predetermined time such as when the main power of the finder is turned on. This way, when calibration is needed,
It is not necessary to forget to perform it and to perform unnecessary calibration.

[0007] The calibration judging section, when judging that the calibration is necessary, issues a warning to the user that the calibration is necessary, and operates the calibration means by the user. And a calibration operation means for performing the operation. With this configuration, when the calibration determination unit determines that calibration is necessary, a warning to that effect is displayed. Users of SLR cameras
The calibration is performed by operating the calibration operation means based on the display.

[0008] The finder preferably further includes individual identification means for identifying an individual of the mounted camera body. In this configuration, since the individual camera bodies can be identified, the necessity of calibration can be effectively determined even if a plurality of camera bodies are used for one finder. The calibration determination unit determines whether calibration is necessary based on the information on the number of times of attaching and detaching the viewfinder acquired by the attachment / detachment detection unit and / or the identification information of the camera body acquired by the individual identification unit. May be determined. The calibration unit may further include an illumination unit provided on a camera body or a viewfinder to illuminate the reference mark, and the calibration unit shields light incident on the camera body from the photographing lens. It is better to calibrate the condition. With this configuration, the calibration can be performed without being affected by the light incident from the photographing lens, and thereby the accuracy of the calibration can be improved.

The calibration means preferably further comprises a confirmation means for confirming whether or not the light incident from the photographing lens has been normally shielded when performing the calibration. Advantageously, means are provided for notifying or displaying to the user that said calibration means is in operation.

The present invention also relates to a finder for a single-lens reflex camera for detachably attaching to a camera body having a reticle, wherein the finder can detect a reference mark provided on the reticle corresponding to a film position. Focus detection means for detecting the focus position of the finder, displacement detection means for detecting the displacement between the reference mark and the focus position, and calibration for correcting the data of the focus position based on the output of the displacement detection means. Based on information obtained by the attachment / detachment means, the storage unit for storing the correction amount calculated by the calibration means, the attachment / detachment detection means for detecting the attachment / detachment of the finder, and the attachment / detachment detection means.
A finder for a single-lens reflex camera, comprising: a determination unit for determining whether calibration is necessary.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a single-lens reflex camera of the present invention will be described below with reference to the drawings. (1) First Embodiment First, a first embodiment of a single-lens reflex camera of the present invention will be described. The feature of the first embodiment is that it has a so-called “focus aid” function.

(1.1) Overall Structure of Camera Hereinafter, the overall structure of the camera in the first embodiment of the single-lens reflex camera of the present invention will be described. Referring to FIGS. 1 and 2, a single-lens reflex camera 1100 of the present invention is a single-lens reflex camera of an interchangeable finder type, and includes a camera body 110, a photographing lens 130, and a finder 11.
40 and a film back 190.

A viewfinder 1140 is provided for the camera body 11.
It is detachably attached to 0. For example, a finder guide groove is provided on the upper surface of the camera body 110, and a finder mounting band is provided on the finder 1140.
Is provided on the lower surface of. The finder mounting band is fitted into the finder guide groove, and the finder 114 is inserted.
The viewfinder 1140 can be attached to the camera body 110 by sliding the 0 with respect to the camera body 110.

The taking lens 130 is detachably attached to the camera body 110. For example, a bayonet mounting portion is provided on the rear surface of the photographing lens 130, and a bayonet mount portion is provided on the front surface of the camera body 110. The bayonet mounting portion of the photographing lens 130 is fitted to the bayonet mount portion of the camera body 110, and the photographing lens 130 is rotated with respect to the camera body 110.
Can be attached to The taking lens 130 has the optical axis 1
06, a taking lens optical system 134, an aperture 136, a shutter 132, and a distance adjusting mechanism (not shown). A film 192 is contained in a film bag 190. The film 192 may be manually fed, or a film feed motor may be provided to
2 may be sent automatically. As a modification, a structure in which the photographing lens 130 is fixed to the camera body 110 may be used. As a modified example, as described later,
Without providing the film back 190, the film 1
The structure in which 92 is arranged in the camera body 110 may be used.

(1.2) Structure of Camera Body The structure of the camera body in the first embodiment of the single-lens reflex camera of the present invention will be described below. A mirror 112 for changing the path of light from the subject through the taking lens 130 is attached to the camera body 110. A condenser lens 114 is provided in the camera body 110 to correct a peripheral light drop in the viewfinder 140. The camera body 110 is set so that the reticle 1116 is optically conjugate to the position of the surface of the film 192.
Is provided. The plane side of the condenser lens 114 is disposed so as to be in contact with one surface of the reticle 1116.

The shutter button 120 is connected to the camera body 1
10. The shutter button 120 may be disposed on the front of the camera body 110, may be disposed on the top of the camera body 110, or may be disposed on the side of the camera body 110. A shutter speed setting dial 122 is provided on a side surface of the camera body 110. A winding crank 124 for winding the film 192 is provided on a side surface of the camera body 110. Control of the shutter speed may be mechanical,
It may be electronic. In a configuration in which the shutter speed is controlled electronically, a crystal unit (not shown) for controlling the shutter speed, an IC (not shown), and a battery (not shown) are connected to the camera body 110. It is good to build in. As a modified example, a structure in which a film winding motor (not shown) for winding the film 192 is built in the camera body 110 may be used. In this configuration, a battery for operating the film winding motor is built in the camera body 110, and the battery can operate the crystal oscillator and the IC to control the shutter speed.

The film 192 is wound up, and the shutter speed is set by a shutter speed setting dial 122.
By pressing the shutter button 120, the shutter 1
32 operates. As a modified example, a structure in which the shutter 132 is not provided in the photographing lens 130 but the shutter is built in the camera body 110 may be used. That is, the single-lens reflex camera of the present invention may be a single-lens reflex camera with a built-in lens shutter, a single-lens reflex camera with a built-in focal plane shutter, or a lens shutter and a focal plane. It may be a single-lens reflex camera with a built-in shutter.

(1.3) Structure of Viewfinder The structure of the viewfinder in the first embodiment of the single-lens reflex camera of the present invention will be described below. The finder 1140 includes a first prism 142 for changing a path of a light beam from the subject passing through the condenser lens 114 and the reticle 1116, and a second prism for changing a path of a light beam from the subject passing through the first prism 142. 144, a third prism 146 for changing the path of a light beam from the subject passing through the second prism 144, and an eyepiece 148 for enlarging an image of the subject passing through the third prism 146. The light flux from the subject passing through the taking lens 130 is changed in path by the mirror 112, passes through the condenser lens 114 and the reticle 1116, and becomes an erect image by the first prism 142, the second prism 144, and the third prism 146. Be composed. Therefore, the user can use the erect image of the eyepiece 148
You can see it enlarged. As a modification, a plurality of mirrors having the same operation and effect as the prism may be used without using the prism.

The detection prism 150 is the first prism 14
2 is provided on the upper side surface 142a that first reflects light passing through the reticle 1116. Part or all of the contact portion between the detection prism 150 and the first prism 142 is configured as a half mirror. Two separator lenses 15 for condensing the light beam from the detection prism 150
2 and 153 are provided in the viewfinder 140. The two separator lenses 152 and 153 are arranged at an interval from each other. The first separator lens 152 is provided to condense one of two spaced light beams that pass through the photographing lens 130. The second separator lens 153 is provided to collect the other of the two light beams that pass through the imaging lens 130 and are spaced apart from each other. For simplicity, only the separator lens 152 is shown in FIG.

The light beams condensed by the separator lenses 152 and 153 are incident to detect the focal point of the image of the object, that is, the position between the image forming plane (object image plane) of the taking lens 130 and the film equivalent plane. A focus detection sensor 154 serving as focus detection means for detecting a shift amount (a defocus amount or a defocus amount) is provided by a finder 1140.
Is provided. The focus detection sensor 154 is preferably an area sensor constituted by a CCD or the like. Alternatively, the focus detection sensor 154 may be a line sensor. The focus detection sensor 154 includes the separator lenses 152 and 15
It is arranged at a position where the light condensed by 3 can be received.

A display unit 156 for displaying the result of detecting the focus of the image of the subject is provided in the finder 1140. The display unit 156 includes, for example, a display element such as an LED. The display unit 156 may be configured by an LCD. The display prism 158 for changing the path of the light flux of the display content displayed on the display unit 156 is provided by the viewfinder 114.
0 is provided. Part or all of the contact portion between the display prism 158 and the first prism 142 is configured as a half mirror. The light flux of the display content displayed by the display unit 156 is configured to be an erect image by the first prism 142, the second prism 144, and the third prism 146. Therefore, the user can view the display content displayed by the display unit 156 by enlarging it with the eyepiece 148. A buzzer 186 for generating a sound based on the result of measuring the distance from the subject to the surface of the film 192 is provided in the finder 1140.

Referring to FIG. 1, the focus detection sensor 154
For processing information on the focal point of the image of the subject detected by the above, and outputting a signal related to the calculation result.
C1160 is provided in viewfinder 1140. Further, a quartz oscillator 162 constituting a source oscillation for outputting a reference signal for arithmetic processing in the IC 1160 is provided in the finder 1140. Also, the focus detection sensor 1
A battery 164 that constitutes a power source for operating the IC 54 and operating the IC 1160 is provided in the viewfinder 1140.
In a single-lens reflex camera in which a battery is provided in the camera body 110, the focus detection sensor 154 is operated by the battery provided in the camera body 110 to operate the IC 1160 without providing the battery 164 in the finder 1140. can do. Finder 1
140 also has a detachment detecting means 1130 for detecting the attachment of the finder to the camera body or the removal from the camera body. The attachment / detachment detecting means 1130 can be constituted by any appropriate element such as a limit switch and an optical switch.

Referring to FIG. 2, the focus detection sensor 154
The viewfinder 1140 is provided with a mode changeover switch 166 which is a calibration operation means for switching the operation mode of the camera. The mode switch 166 may be a rotary switch, a slide switch, a push switch, or a touch sensor switch.

(1.4) Reference Mark and Mark Light Source Referring to FIG. 1, a reference mark 1118 is provided on the reticle 1116 to measure the distance between the camera body and the focus detection sensor. The reference mark 1118 is preferably provided on a surface of the reticle 1116 opposite to the surface facing the first prism 142. Therefore, in this configuration, the reference mark 1118 is
0 is fixedly provided. Fiducial mark 111
Reference numeral 8 denotes an image of the reference mark 1118 formed by the separator lens 15.
It is arranged at a position where light can be condensed on the focus detection sensor 154 by 2 and 153. That is, the focus detection sensor 15
Reference numeral 4 is arranged at a position where the image of the reference mark 1118 collected by the separator lenses 152 and 153 can also enter.

Referring to FIG. 3, FIG.
18 shows 18 examples. Referring to FIG. 3A, a reference mark 1118a shows a configuration in which a detection frame is also used as a reference mark. Referring to FIG. 3B, the reference mark 1118b shows a case where the reference mark has a cross shape. Referring to FIG. 3C, the reference mark 1118c
Indicates that the reference mark is formed in a circular shape. The size of the reference mark 1118 is partially determined by the focus detection sensor 15.
Any size can be used as long as it can be recognized in Step 4.

Referring to FIG. 4, the reference mark 1118 is formed as an acute-angle groove 1118g on the surface of the reticle 1116 opposite to the surface facing the first prism 142 (the surface where the condenser lens 114 is located). Is done. The width and depth of the groove 1118g constituting the reference mark 1118,
The vertex angle θ has only to have a dimension such that a part of the reference mark 1118 can be recognized by the focus detection sensor 154. The groove 1118g of the reference mark 1118 may be formed by grinding, or may be formed by partial etching.

A mark light source 1120 as an illuminating means for illuminating the groove 1118g of the reference mark 1118 is provided in the finder 1140. Mark light source 1120
May be a lamp or an LED.
The mark light source 1120 is configured to illuminate the groove 1118g from the direction in which the condenser lens 114 is arranged. The mark light source 1120 is preferably configured to use a battery 164 provided in the viewfinder 1140 as a power source. Alternatively, the mark light source 1120 is
Alternatively, a battery (not shown) provided at 0 may be used as a power source.

As a modification, referring to FIG. 5, the mark light source 1120 may be configured to illuminate the groove 1118 g from the side of the condenser lens 114. In this configuration, the light beam emitted from the mark light source 1120 is
The light is reflected by the surface of the condenser lens 114 to form the groove 111.
It is configured to illuminate 8g.

As a modification, the mark light source 1120
Light reflected from the condenser lens 114 may be reflected by one or more mirrors (not shown) to illuminate the groove 1118g from the side of the condenser lens 114, or the condenser lens 114 The groove 1118g may be configured to be illuminated from a direction at an angle to the surface of the groove 1118g.

As a modification, the camera body 110 may be provided with a mark light source 1120 for illuminating the groove 1118g. In this configuration, the mark light source 1120
The groove 1118 is formed from the direction in which the condenser lens 114 is arranged.
g. In this configuration, the mark light source 1120 may be configured to use a battery (not shown) provided in the camera body 110 as a power source.

(1.5) Configuration of Detector The configuration of the detector in the first embodiment of the single-lens reflex camera of the present invention will be described below. Referring to FIG. 6, a sensor control unit 170 for controlling the operation of the focus detection sensor 154 is provided. The sensor control unit 170 is configured to change the operation mode by operating the mode changeover switch 166. When the mode changeover switch 166 is set to the photographing mode, the light beam from the subject 104 passes through the photographing lens 130, the mirror 112, the condenser lens 114, the reticle 1116, and the detection optical system (the detection prism 150, the separator lenses 152 and 153). It is configured to enter the focus detection sensor 154. When the mode changeover switch 166 is set to the calibration mode, the mirror 112 is mirrored up (the mirror 112 is oriented in the horizontal direction), and the light beam from the photographing lens does not enter the condenser lens 114.

Here, the sensor control section 170 is configured to illuminate a line corresponding to the groove 1118g of the reference mark 1118 by turning on the mark light source 1120 provided outside the photographing optical path. At this time, the sensor control unit 1
70 is configured to detect the position of the reference mark 1118 based on the light beam incident on the focus detection sensor 154.

A focus calculation unit 172 as a shift amount detecting means
Is provided to detect a focus of an image of a subject by inputting a signal regarding the subject 104 output by the focus detection sensor 154. A finder position calculation unit 174 that forms a part of the calibration unit is provided for measuring the optical path length from the focusing screen 1116 to the focus detection sensor 154.

A correction operation unit 176 which constitutes a part of the calibration means outputs a signal relating to the detection result of the focus of the image of the subject output from the focus operation unit 172 and a focus signal from a focusing screen 1116 output from the finder position operation unit 174. It is provided to correct the detection result of the focus of the image of the subject based on the signal regarding the optical path length up to the detection sensor 154. That is, the single-lens reflex camera of the present invention is configured to correct the detection result of the focus of the subject image by the focus detection sensor 154 based on the result of measuring the position of the reference mark 1118 using the focus detection sensor 154. You. The storage unit 177 is provided to store the correction amount calculated by the correction operation unit 176. The storage unit can be constituted by, for example, an electrically erasable programmable read only memory (EEPROM).

On the other hand, information on the number of times of mounting the finder detected by the attachment / detachment detecting means 1130 for detecting attachment / detachment of the finder 1140 is stored in the storage unit 177. The calibration determination unit 179 stores in the storage unit 1
It is provided to determine whether or not to issue a warning that calibration is necessary, based on information such as the number of times the finder 1140 has been mounted, which is stored in 77. Further, the sensor control unit 170 includes a mode changeover switch 166
Is set to the calibration mode, the mark light source 11
20 is turned on.

(1.6) Configuration of Output Unit The configuration of the output unit in the first embodiment of the single-lens reflex camera of the present invention will be described below. Referring to FIG. 6, the output control unit 178 includes a mode changeover switch 166.
Is operated to switch the output mode, output an output signal based on the detection result of the focus of the image of the subject, or display the result of calibration. A display drive unit 180 is provided to input the output signal output by the output control unit 178 to operate the display unit 156 and display information on the correction result calculated by the correction calculation unit 176.

A sound output drive section 182 is provided for inputting an output signal output from the output control section 178 to operate the sound output section 184 and to output a sound based on the correction result calculated by the correction operation section 176. For example, the sound generator 184 includes a buzzer 186 or a speaker. For example, sound generator 1
Numeral 84 is configured to emit sound when the correction result of the focus of the image of the subject calculated by the correction calculation unit 176 is in a focused state. Alternatively, the sound generation unit 184 emits a low sound when the focus correction result of the image of the subject calculated by the correction calculation unit 176 is a so-called “front focus”, and emits a high sound when the focus correction result is a “back focus”. Alternatively, an intermediate sound may be output when the subject is in focus.

If not necessary, the display driver 18
0 and the display unit 156 may not be provided, or the sound generation drive unit 182 and the sound generation unit 184 may not be provided. By operating the mode change switch 166, an output mode in which only the display unit 156 is activated can be set, and an output mode in which only the sound generation unit 184 can be activated can be set. Pronunciation section 18
4 so that an output mode for operating both of them can be set. On the other hand, when the calibration determination unit 179 determines that calibration is necessary, the calibration determination unit 179
From the display driving unit 18
The output control unit 178 is configured to display a warning indicating that calibration is required on the display unit 156 via the “0”. At the same time, the output control unit may be configured to emit a warning sound from the sound generation unit 184 via the sound generation drive unit 182.

In the embodiment of the single-lens reflex camera of the present invention, circuits for performing various functions are preferably formed in the IC 1160. In the first embodiment of the single-lens reflex camera of the present invention, the sensor control unit 170 and the focus calculation unit 17
2. Finder position calculator 174, correction calculator 17
6, storage unit 177, output control unit 178, calibration determination unit 179, display drive unit 180, sound generation drive unit 18.
2 is configured in the IC 1160. Further, the IC 1160
Inside, a CPU, a ROM, a RAM and the like are provided.

The IC 1160 may be a PLA-IC having programs for performing various operations. In the embodiment of the single-lens reflex camera of the present invention,
If necessary, external elements such as a resistor, a capacitor, a coil, a diode, and a transistor can be used together with the IC.

(1.7) Operation of Single-Lens Reflex Camera The operation of the first embodiment of the single-lens reflex camera of the present invention will be described below. Here, referring to FIG. 1, FIG. 6, and FIG. 7, FIG.
The optical path up to 54 is written equivalently, and the optical axis is 1
06, the mirror 112, the upper side surface 142a, and the detection prism 150 are shown in an expanded manner.

In the detection area of the single-lens reflex camera of the present invention,
It is preferable to provide a condenser lens 114H that matches the characteristics of the focus detection sensor 154. The purpose of providing such a condenser lens 114H is to separate the subject 10 into two.
4 is to pass a certain area at the exit pupil position of the taking lens 130. In particular,
The condenser lens 114H is configured such that the image of the aperture 143A1 near the separator lenses 152 and 153 forms a characteristic near the exit pupil position of the photographing lens 130.

Here, since the exit pupil position differs depending on the photographing lens, it is necessary to set a virtual reference exit pupil position. The condenser lens 1 as a finder
14H is configured to have such a characteristic that an image of the exit pupil is formed near the eyepiece. The focal length of the condenser lens 114H as the finder and the focal length of the condenser lens 114H as the focus detection sensor 154 are not necessarily the same. Therefore, as shown in FIG. 7, the focal length of the region of the condenser lens 114H for detecting the focus of the image of the subject is determined by the focus detection sensor 154.
It is preferable that the focal length of the condenser lens 114H as a finder be the focal length of the condenser lens 114H as a finder. .

1 of the subject 104 whose optical axis is located at 106
The light beam emitted from the point 104P is refracted by the taking lens 130, changed the path by the mirror 112, passes through the condenser lens 114, passes through the detection area of the reticle 1116, and passes through the aperture 143A2 and the aperture 14
The light passes through 3A1 and is imaged by the separator lenses 152 and 153 in two regions near the imaging surface of the focus detection sensor 154.

Since the focusing screen 1116 is originally provided for the purpose of focusing, assuming that the focusing lens 1116 has a necessary and sufficient accuracy with respect to the focusing, the image formed on the focusing screen 1116 is focused on by the focus detecting sensor 154. As a result, the image is detected as an image having a defocus amount of zero. On the other hand, reticle 1
When the reference mark 1118 is provided on the imaging surface of the reference numeral 116, the image of the reference mark 1118 is also
At 54, the image is detected as an image having a defocus amount (a defocus amount) of zero. However, when an error occurs in the optical path length from the focusing screen 1116 to the focus detection sensor 154 due to a variation in the assembly of the viewfinder 1140 or the like, the defocus amount of the image of the reference mark 1118 is detected as a value other than zero. .

For this reason, a reference mark 1118 is provided in advance in a part of the detection area of the reticle 1116, and the reference mark 1118 is recognized by the focus detection sensor 154. An error in the optical path length with respect to the reticle 1116 can be obtained. Using the obtained error, the detection result of the focus of the image of the subject detected by the focus detection sensor 154 can be corrected.

Referring to FIGS. 4 and 5, as described above, in the embodiment of the present invention, the reference mark 1118 is located on the surface of the reticle 1116 opposite to the surface facing the first prism 142 (the condenser lens). A groove 1118g is formed on the surface on which 114 is located). Therefore, the light beam with the open angle A1 emitted from the photographing lens 130 is refracted by the groove 1118g of the reference mark 1118 to become a light beam with the open angle A2. As a result, since the light beam with the opening angle A2 does not reach the focus detection sensor 154, the line corresponding to the groove 1118g of the reference mark 1118 is always recognized as black by the user.

However, if the image of the subject 104 is located around the reference mark 1118, the defocus amount (phase difference) of the reference mark 1118 cannot be accurately detected only from the area where the reference mark 1118 exists. That is, in the pixel existing at the boundary between the image of the reference mark 1118 and the image of the subject, the image of the reference mark 1118 is formed in a part of the pixel. A light amount between the light amount and the light amount is detected. Therefore, the amount of light detected by the pixels present at the boundary varies depending on the subject, and it becomes difficult to accurately detect the position of the reference mark 1118. Therefore, by turning on the mark light source 1120 provided outside the photographing optical path, the reference mark 1118 is illuminated, and the mark light source 1120 is illuminated.
By comparing the data output from the focus detection sensor 154 in the two states of the light-on state and the light-off state, the detection accuracy of the position of the reference mark 1118 can be improved.

However, in the method of comparing the light-on state and the light-off state of the mark light source 1120, the reference mark 11
The time required to detect the position 18 increases, and the influence of the image of the subject cannot be completely eliminated. Therefore, preferably, in the calibration mode, the mirror 112 is mirrored up and the photographing lens 130 is moved up.
From reaching the reticle 1116.
Therefore, in the calibration mode, the focusing screen 111
6 is irradiated only with the light from the mark light source 1120.

Next, reference is made to FIG. FIG. 8 is a diagram schematically illustrating information on the reference mark 1118 output by the focus detection sensor 154 when the mark light source 1120 is turned on. That is, at the position of the image of the reference mark 1118,
The light amount detected by the focus detection sensor 154 is substantially zero, and otherwise, a substantially constant light amount is detected.
8A shows the case where the optical path length from the reference mark 1118 of the focusing screen 1116 to the focus detection sensor 154 is longer than the design value, and FIG. 8B shows the case where the optical path length from the reference mark 1118 to the focus detection sensor 154 is designed. If it is shorter than the value, FIG.
FIG. 3C is a diagram schematically illustrating the shapes of signals output from the focus detection sensors 154 when the optical path length is as designed. In FIG. 8A, a waveform 152a2 indicates a waveform of an image formed on the focus detection sensor 154 by the separator lens 152, and a waveform 153a2 indicates a waveform of an image formed on the focus detection sensor 154 by the separator lens 153.

In FIG. 8B, a waveform 152b2 shows a waveform of an image formed on the focus detection sensor 154 by the separator lens 152, and a waveform 153b2 shows a waveform of an image formed on the focus detection sensor 154 by the separator lens 153. Show. In FIG. 8C, waveform 1
52c2 indicates a waveform of an image formed on the focus detection sensor 154 by the separator lens 152, and a waveform 153
c2 indicates a waveform of an image formed on the focus detection sensor 154 by the separator lens 153. In FIG. 8C, the position shift amount (phase difference) DMS of the focus detection light flux between the waveform 152c2 and the waveform 153c2 is predetermined as a design value of the single-lens reflex camera of the present invention. Therefore, the finder position calculation unit 174 stores the value of the position shift amount DMS in advance.

As shown in FIG. 8A, the reticle 1116
When the optical path length from the reference mark 1118 to the focus detection sensor 154 is longer than the design value, the finder position calculation unit 174 calculates the position shift amount (phase difference) DMC between the waveforms 152a2 and 153a2, and calculates the calculation. Result and D
The optical path length from the reference mark 1118 to the focus detection sensor 154 is calculated by comparing the MS. On the other hand, as shown in FIG. 8B, when the optical path length from the reference mark 1118 to the focus detection sensor 154 is shorter than the design value, the finder position calculation unit 174 outputs the waveform 152b.
2 (waveform 153b2) and displacement 153b2 (phase difference) DM
By calculating F and comparing the calculation result with DMS, the optical path length from the reference mark 1118 to the focus detection sensor 154 is calculated.

Next, the correction operation unit 176 is operated by the focus operation unit 1
The calculation result of the focus of the image of the subject output by the reference position calculation unit 174 and the reference mark 1118 output by the finder position calculation unit 174
The calculation result of the focus of the image of the subject is corrected based on the calculation result of the optical path length from to the focus detection sensor 154. The corrected calculation result for the focus of the image of the subject is output to the output control unit 178. Further, the correction amount of the focus calculation result is stored in the storage unit 177.

For example, as shown in FIG. 8A, the focus detection sensor 15
If the optical path length up to 4 is longer than the design value, DMC and DM
Correction is made so that the DJS reference value to be brought into the in-focus state becomes smaller by the difference value of S. On the other hand, for example, FIG.
As shown in (b), the reference mark 11 on the reticle 1116
If the optical path length from 18 to the focus detection sensor 154 is shorter than the design value, the correction is made so that the reference value of the DJS to be brought into focus is increased by the difference between DMF and DMS.

FIG. 9 shows the procedure for detecting the defocus amount of the mark image in the calibration mode. When the mode switch 166 is set to the calibration mode, the calibration process is started. First, in step S1, the sensor control unit 170 mirrors up the mirror 112 so that the light from the photographing lens 130 does not reach the focusing screen 1116. However, this operation need not be performed. Next, in step S2, a display indicating that the calibration process is being performed is displayed on the display unit 156, for example, in the viewfinder field. In step S3, the sensor control unit 170 turns on the mark light source 1120. However, this operation need not be performed. In step S4, image data of the reference mark 1118 formed on the focus detection sensor 154 is temporarily stored, and the image data is stored in step S4.
At 5, the finder position calculation unit 174 takes in. Next, in step S6, the sensor control unit 170 turns off the mark light source 1120. Of course, when the mark light source is not turned on, this operation need not be performed.

In step S7, the finder position calculator 174 calculates the amount of defocus of the image of the reference mark 1118, and the correction calculator 176 calculates the amount of correction of the image of the subject based on the amount of defocus. This correction amount is determined in step S8.
Is stored in the storage unit 177. Subsequently, in step S9, a message indicating that the calibration process has been completed is displayed. Finally, in step S10, the mirror-up is released, and the calibration processing ends.
Of course, this operation is not performed when the mirror is not raised. Depending on the application, whether the light beam from the taking lens was properly blocked by the mirror up, etc.
A confirmation process of whether or not the calibration process has been completed normally may be performed.

FIGS. 10A to 10C show the calibration mode indicators displayed at the bottom of the finder visual field. When the mode changeover switch 166 is set to the calibration mode, as shown in FIG. 10A, the “C” mark 149f on the right end of the indicator flashes, indicating that the calibration is being performed. Next, when calibration is completed normally,
As shown in FIG. 10B, the “C” mark 149 f changes from blinking to lighting. When performing the process of confirming the normal termination of the calibration, the “E” mark 149f may be blinked as shown in FIG. 10C to notify the calibration abnormality.

When the mode changeover switch 166 is set to the photographing mode, the light beam incident from the photographing lens 130 passes through the mirror 112, the condenser lens 114, the focusing plate 1116, and the detecting optical system, and the focus detecting sensor 154.
To reach. Next, the focus detection sensor 154 and the focus calculation unit 172 connect the subject 10 formed on the focusing screen 1116 to the subject 10.
The amount of defocus of the subject 104 is calculated based on the image of No. 4. This defocus amount is sent to the correction calculation unit 176. The correction calculation unit 176 corrects the defocus amount based on the correction amount calculated in the calibration mode and stored in the storage unit 177. Next, the output control unit 17
8 operates the display drive unit 180, and the display unit 156 displays the defocus amount of the image of the subject corrected by the correction calculation unit 176. The output control unit 178 activates the sound generation drive unit 182, and the sound generation unit 184 emits sound based on the defocus amount of the focus of the subject image corrected by the correction calculation unit 176. For example, the buzzer 186 emits a sound when the defocus amount corrected by the correction calculation unit 176 is zero, that is, when the camera is in a focused state.

Next, an algorithm for determining the necessity of calibration executed by the calibration determining unit 179 will be described. Many causes of the variation in the optical path length from the focusing screen 1116 of the camera body 110 to the focus detection sensor 154 are generally caused by the finder 1140.
It is considered that this depends on how the camera body 110 is attached to the camera body 110. Therefore, once the finder 1140 is attached to the camera body 110, the finder 1140
The optical path length does not change until the lens is remounted. Therefore, in the present embodiment, it is determined whether or not the viewfinder 1140 has been mounted again after the previous calibration was performed.

FIG. 11 is a flowchart of a process for counting the number of times the finder 1140 has been mounted.
When the finder 1140 is mounted on the camera body 110, the attachment / detachment detecting means 1130 detects the detection. When the mounting of the viewfinder 1140 is detected, the processing of the flowchart in FIG. 11 is started. First, in step S101, the number of mountings of the viewfinder 1140 up to the previous time stored in the storage unit 177 is acquired. When the finder 1140 is attached to the camera body 110 for the first time, the number of attachments is zero. Next, step S10
In step 2, the number of attachments acquired in the previous step is increased by 1, that is, 1 is added to the number-of-attachments counter. Finally, in step 103, the number of mountings increased in the previous step, that is, the updated value of the number-of-mounting counter is stored in the storage unit 177, and the process ends.

Next, with reference to FIG. 12, a description will be given of the number counter storing process performed after the mark image defocus amount detecting process shown in FIG. Mode switch 16
6 is switched to the calibration mode, the mark image defocus amount detection processing shown in FIG. 9 is performed, and subsequently, the processing of FIG. 12 is performed. In step S201, the value of the mounting counter stored in the storage unit 177 in step S103 of FIG. 11 is obtained. Next, in step S202, the value of the mounting number counter acquired in the previous step is substituted into the mounting number counter during calibration. Finally, in step S203, the value of the mounting number counter at the time of calibration, to which the value has been substituted, is stored in the storage unit 1.
Store in 77. With the above processing, the number of times of mounting the finder at the time when the calibration processing is executed is stored as the value of the mounting number counter at the time of calibration.

Next, a process for checking the necessity of calibration will be described with reference to FIG. This process is performed, for example, when the main power of the finder 1140 is turned on. First, in step S301, the value of the mounting frequency counter stored in the storage unit 177 is obtained. Next, in step S302, the value of the mounting number counter at the time of calibration stored in the storage unit 177 is acquired. In step S303, the acquired value of the mounting number counter is compared with the value of the mounting number counter at the time of calibration. When the values of these two counters are equal to each other, there is no need to perform calibration, and thus this check processing is terminated. That is, the reason why the values of the two counters are equal is that the finder 1140 has not been attached or detached since the previous calibration, and in that case, the optical path length from the focusing screen 1116 to the focus detection sensor 154 is reduced. It is considered that no change occurs. If the values of the two counters are different,
Viewfinder 1140 after previous calibration
Has been re-mounted, the process proceeds to step S304,
A warning that calibration needs to be performed is issued, and this process ends.

The warning is displayed at the lower part of the viewfinder as shown in FIG. For example, a warning can be issued by blinking the “C” mark at the lower right end of the viewfinder field of view. As shown in FIG.
When the display during the calibration process is also performed by the blinking of the “C” mark, the blinking period is different between the case of the warning and the case of the calibration process so that those displays can be distinguished. It is good to configure.

Referring to FIG. 15, an outline 149a of the field of view of the finder is shown in the single-lens reflex camera of the present invention. A frame 149b indicating the detection area is shown in the view of the finder, and the frame 149b is the reference mark 111.
8 is the image made by A character 149c indicating the set shutter speed “1/250” and a character 149d indicating the set aperture value “5.6” are indicated in the upper part outside the field of view of the finder. In the viewfinder with a built-in light meter, the figure 14
9e is pointed to the top outside the field of view of the viewfinder.

For example, in the case of a proper exposure state, the green LED in the center lights up, and in the case of “underexposure”,
The orange LED located on the right lights up, indicating "overexposure"
, The red LED located on the left lights up.
As the degree of “underexposure” increases, a larger number of orange LEDs light. As the degree of “overexposure” increases, a larger number of red LEDs light. The red LED is a triangle with a pointed top, and the orange LED is a triangle with a pointed bottom.

Symbol 1 indicating the detection result of the focus of the image of the subject
49 g is indicated at the bottom outside the viewfinder field.
For example, in the case of a focused state, a diamond at the center and a green LE
When D is illuminated and is “back pin”, the orange LED located to the right thereof is illuminated, and when it is “front pin”, the red LED located to the left thereof is illuminated. As the degree of “back focus” increases, a larger number of orange LEDs light up. As the degree of “front pin” increases, a large number of red LEDs light up. The red LED and the orange LED are square. With this configuration, the detection result of the focus of the image of the subject can be clearly displayed. According to the first embodiment of the present invention, it is possible to provide a single-lens reflex camera that does not forget to calibrate after re-attaching the viewfinder.

(2) Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. The present embodiment is different from the first embodiment in that a function for identifying an individual camera body 110 is provided, and whether or not calibration is necessary is determined based on the information. Other configurations, operations, and effects are the same as those of the first embodiment, and thus description thereof is omitted. This embodiment is a single-lens reflex camera in which it is clear that the optical path length from the reticle 1116 to the focus detection sensor 154 does not change even if the finder is attached and detached a fixed number of times if the finder is attached to the same individual camera body. Especially effective.

As shown in FIG. 16, according to the second embodiment of the present invention, in order to identify an individual camera body, a camera body ID which is information for identifying the individual camera body is provided in the camera body 110. And a CPU (Central Processing Unit) 128 for extracting data from the read-only memory.
The read-only memory 126 is, for example, an EEPROM,
It can be constituted by a nonvolatile memory, a magnetic storage medium, or the like. The single-lens reflex camera 1100 according to the present embodiment further includes a data transmission unit 129 for transmitting information for identifying the individual camera body read from the read-only memory 126 by the CPU 128 to the finder 1140. The data transmission unit 129 can be configured by, for example, electrical contacts provided on the camera body 110 and the viewfinder 1140, respectively.

Next, the calibration processing of this embodiment will be described with reference to FIG. When the mode changeover switch 166 is switched to the calibration mode, the calibration processing of the flowchart shown in FIG. 17 is started. In the calibration processing, first, the mark image defocus amount detection processing shown in FIG. 9 is performed. When the processing in FIG. 9 is completed, step S4 in FIG.
Go to 01. In step S401, the value of the mounting number counter stored in the storage unit 177 is obtained. Next, in step S402, the value of the mounting number counter acquired in the previous step is substituted into the mounting number counter during calibration. Further, in step S403, the value of the mounting number counter during calibration, into which the value has been substituted, is stored in the storage unit 177.

Next, in step S405, the CPU 128 and the data transmission means 1
A camera body ID, which is information for identifying the individual camera body 110, is obtained via the interface 29. As the camera body ID, any appropriate numerical value and code such as a model and a serial number of the camera body can be used. Next, in step S406, the value of the camera body ID obtained in the previous step is substituted for the value of the camera body ID at the time of calibration. Finally, step S407
Then, the value of the camera body ID at the time of calibration is stored in the storage unit 177. By the above processing, the number of times of mounting the finder at the time when the calibration processing is executed and the code for identifying the individual camera body that has been calibrated are stored in the storage unit 177.

Next, a processing algorithm for checking the necessity of calibration will be described with reference to FIG. This process is executed when the main power supply of the finder 1140 is turned on by the calibration determining unit 179. First, in step S501, the camera body ID is obtained from the read-only memory 126 of the camera body 110. Next, in step S502, the camera body ID at the time of calibration, which is already stored in the storage unit 177, is obtained. Then
In step S503, the camera body ID acquired in step S501 is compared with the camera body ID at the time of calibration acquired in step S502. If the values of these camera body IDs are different, the process proceeds to step S507, and a warning indicating that calibration is necessary is displayed. That is, when the values of the two camera body IDs are different, the viewfinder 11
Since the camera body attached to 40 is different from the camera body attached when the previous calibration was performed, it is necessary to perform a new calibration. As described above, the calibration determination unit 179 and the storage unit 177 also function as individual identification means for identifying an individual camera body.

If the camera body ID obtained in step S501 is equal to the camera body ID at the time of calibration, the process proceeds to step S504. In step S504, the value of the mounting counter stored in the storage unit 177 is obtained. Further, step S505
Then, the value of the mounting number counter at the time of calibration stored in the storage unit 177 is acquired. Subsequently, in step S506, it is determined whether or not a value obtained by subtracting the value of the number of times of mounting counter at the time of calibration obtained in step S505 from the value of the number of times of mounting counter obtained in step S504 is larger than a predetermined value. Compare. If the difference between the values of the two mounting counters is larger than the predetermined number, the process proceeds to step S507 to display that calibration is necessary, and ends the calibration necessity check process. If the difference between the values of the two mounting frequency counters is smaller than the predetermined number, step S50
The check process is terminated without executing step 7. The predetermined number of times is determined by performing the finder 1
Even if the attachment / detachment of the 140 is repeated, the number of times that it is clear that the optical path length from the focusing screen 1116 to the focus detection sensor 154 does not change due to wear of the mounting portion or the like is set in advance. According to the second embodiment, when the finder is mounted on the same camera body as the camera body at the time of performing the previous calibration, it is necessary to perform the calibration every time even if the finder is mounted again. Disappears. As a modified example, the camera body IDs of a plurality of individuals, the calibration result and the number of times of mounting corresponding to each individual may be stored in the storage unit. This makes it possible to omit calibration even when the viewfinder is re-mounted on a plurality of individual camera bodies.

While the preferred embodiments of the present invention have been described above, various modifications may be made to the disclosed embodiments without departing from the scope or spirit of the present invention within the scope of the technical matters described in the claims. Can be changed. In particular, in the above-described embodiment, the necessity check process of the calibration is configured to be executed when the main power of the finder is turned on. However, depending on the application, a switch for activating the necessity check process may be replaced by a finder or a camera. It may be provided on the body so that the user can operate it appropriately. In the above embodiment, the necessity of the calibration is determined by comparing the number of times of mounting the finder, but the determination may be performed using a flag. In other words, a single-lens reflex camera is configured so that the calibration completed flag is set when the calibration is performed, and this flag is cleared when the finder is attached to the camera body, and when the main power is turned on. The necessity of calibration may be determined based on whether or not the calibration completed flag is set. In the above-described embodiment, the user performs the calibration by setting the mode switch to the calibration mode. However, when the calibration determination unit determines that the calibration is necessary, the calibration is automatically performed. May be configured to be executed.

[0074]

According to the present invention, as described above, the focus detection sensor is disposed in the finder portion of the interchangeable finder type single-lens reflex camera, and the result of electronically detecting the focus of the image of the subject is shown to the photographer. It is possible to correct the detection deviation due to the combination between individuals that occurs between the viewfinder and the camera body, correct the detection deviation of the focus of the subject image due to temperature change, aging, etc. , It is possible to obtain a detection result of the focus of the image of the subject having a high level. Further, according to the present invention, a single-lens reflex camera having an exchangeable finder that can display whether or not calibration is necessary without forgetting to perform calibration for detecting the amount of defocus with high accuracy. Camera obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a single-lens reflex camera of the present invention.

FIG. 2 is a front view showing the first embodiment of the single-lens reflex camera of the present invention.

FIG. 3 is a plan view showing an example of a reference mark used in the first embodiment of the single-lens reflex camera of the present invention.

FIG. 4 is a schematic partial sectional view showing a reference mark and a mark light source used in the first embodiment of the single-lens reflex camera of the present invention.

FIG. 5 is a schematic partial cross-sectional view showing another configuration of a reference mark and a mark light source used in the first embodiment of the single-lens reflex camera of the present invention.

FIG. 6 is a block diagram illustrating a configuration of a first embodiment of the single-lens reflex camera of the present invention.

FIG. 7 is a developed view equivalently showing an optical path from a subject to a focus detection sensor in the first embodiment of the single-lens reflex camera of the present invention.

FIG. 8 is a diagram schematically illustrating information on a reference mark output by a focus detection sensor when a mark light source is turned on in the first embodiment of the single-lens reflex camera of the present invention.

FIG. 9 is a flowchart illustrating a mark image defocus amount detection process executed in a calibration mode in the first embodiment of the single-lens reflex camera of the present invention.

FIG. 10 is a schematic diagram showing an indicator displayed below a finder field of view in the first embodiment of the single-lens reflex camera of the present invention.

FIG. 11 is a flowchart showing a mounting counter update process in the first embodiment of the single-lens reflex camera of the present invention.

FIG. 12 is a flowchart illustrating a calibration-time mounting number counter storage process executed in a calibration mode in the first embodiment of the single-lens reflex camera of the present invention.

FIG. 13 is a flowchart showing a calibration necessity check process in the first embodiment of the single-lens reflex camera of the present invention.

FIG. 14 is a diagram illustrating a display of a calibration execution warning in the first embodiment of the single-lens reflex camera of the present invention.

FIG. 15 is a schematic diagram showing indicators displayed on each part of a finder field of view in the first embodiment of the single-lens reflex camera of the present invention.

FIG. 16 is a block diagram showing a configuration of a second embodiment of the single-lens reflex camera of the present invention.

FIG. 17 is a flowchart illustrating processing executed in a calibration mode in the second embodiment of the single-lens reflex camera of the present invention.

FIG. 18 is a flowchart showing a calibration necessity check process in the second embodiment of the single-lens reflex camera of the present invention.

[Explanation of symbols]

 106 Optical axis 110 Camera body 112 Mirror 114 Condenser lens 120 Shutter button 122 Shutter speed setting dial 124 Hoisting crank 126 Read-only memory 128 CPU 129 Data transmission means 130 Shooting lens 132 Shutter 134 Shooting lens optical system 136 Aperture 142 First prism 142a Side surface 144 Second prism 146 Third prism 148 Eyepiece 150 Detection prism 152, 153 Separator lens 154 Focus detection sensor 156 Display unit 158 Display prism 162 Quartz crystal oscillator 164 Battery 166 Detection switch 170 Sensor control unit 172 Focus operation unit 174 Finder position calculation section 176 Correction calculation section 177 Storage section 178 Output control section 179 Calibration judgment Unit 180 display drive unit 182 sound generation drive unit 184 sound generation unit 186 buzzer 190 film back 192 film 1100 single-lens reflex camera 1116 focus plate 1118 fiducial mark 1120 mark light source 1130 attachment / detachment detection means 1140 viewfinder 1160 IC

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03B 17/20 G03B 3/00 A (72) Inventor Katsuyasu Shimazaki 1385 Hasunuma, Omiya City, Saitama Prefecture Tamron Co., Ltd. (72) Inventor Kimihide Takeda 1385 Hasunuma, Omiya-shi, Saitama F-term, Tamron Co., Ltd. BA15 BB05 CA12

Claims (9)

[Claims] 1. A camera body having a reticle provided with a reference mark corresponding to a film position, a finder removably attached to the camera body, and a focus detection means disposed in the finder and detecting a focus position. A displacement amount detection unit disposed in the fielder for detecting a deviation amount between the reference mark and the focal position; and a calibration unit for correcting data of the focal position based on an output of the deviation amount detection unit. A storage unit for storing the correction amount calculated by the calibration unit, an attachment / detachment detection unit for detecting attachment / detachment of the finder, and information acquired by the attachment / detachment detection unit.
A single-lens reflex camera, comprising: a calibration determining unit for determining whether calibration is necessary. 2. The method according to claim 1, wherein the calibration determination unit uses a warning unit for issuing a warning to the user that calibration is necessary when the calibration determination unit determines that calibration is necessary, and the calibration unit. 2. The single-lens reflex camera according to claim 1, further comprising: calibration operation means for operating by a person. 3. The single-lens reflex camera according to claim 1, wherein the finder further includes an individual identification unit for identifying an individual of the mounted camera body. 4. The calibration judging section performs calibration based on information on the number of times of attaching / detaching the finder acquired by the attachment / detachment detection means and / or identification information of the camera body acquired by the individual identification means. The single-lens reflex camera according to any one of claims 1 to 3, wherein it is determined whether or not is necessary. 5. The apparatus according to claim 1, wherein the calibration unit further includes an illumination unit provided on a camera body or a viewfinder to illuminate the reference mark. The described single-lens reflex camera. 6. The single eye according to claim 1, wherein the calibration unit performs the calibration in a state where light incident on the camera body from a photographing lens is blocked. Reflex camera. 7. The apparatus according to claim 6, wherein said calibration means further comprises a confirmation means for confirming whether or not light incident from the photographing lens has been normally blocked when performing calibration. Single-lens reflex camera. 8. The single-lens reflex camera according to claim 1, further comprising means for notifying or displaying to a user that said calibration means is in operation. camera. 9. A finder for a single-lens reflex camera for detachably attaching to a camera body having a reticle, wherein said finder is capable of detecting a reference mark provided on said reticle corresponding to a film position. A focus detection unit for detecting a focus position of the finder; a shift amount detection unit for detecting a shift amount between the reference mark and the focus position; and data of the focus position based on an output of the shift amount detection unit. Calibration means for correcting the correction amount, a storage unit for storing a correction amount calculated by the calibration means, an attachment / detachment detection means for detecting the attachment / detachment of the finder, and information On the basis of,
A finder for a single-lens reflex camera, comprising: a determination unit for determining whether calibration is necessary.