JPH0954243A - Focus detector and camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove deviation between a focal position obtained by a focus detecting means and a focal position on an image forming plane even when an optical path length to the focus detecting means is changed due to the increase in the number of times of operation of an optical member provided in a focus detecting optical system. SOLUTION: The number of operating times of a first half mirror 9 for reflecting a part of light beams passed through, for example in a camera, a photographic lens and introducing it to the side of a finder optical system and a second mirror M1 for guiding a remaining passed light beam to a focus detecting means and the number of releasing times complied with this number of operating times or the number of auto-loading times are counted. A focus compensating amount at the time of counting is read out from a storage means 101b stored in advance and focus information obtained by a focus detecting mean 102 is compensated by means of a focal position changing means 101a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus detecting device and a camera having a focus detecting means for detecting a focus state of an optical system, and a focus optical system having an optical member which operates in association with a focus detecting operation. Related to the improvement of.

[0002]

2. Description of the Related Art Conventionally, a light quantity distribution for two objects is formed from light fluxes passing through different areas of a pupil of a taking lens, and a focus state of the taking lens is detected from a relative positional relationship of the light quantity distributions. The so-called image shift type focus detection device is known.

In a focus detecting device used for a single-lens reflex camera or the like, a sub-mirror integrally provided with a reflex mirror is used to bend a part of the subject light to introduce it into a focus detecting system. It is proposed that a focus detection optical system is arranged between the flex mirror and the shutter curtain so that the focus detection optical system can be moved in and out during distance measurement and shooting, or a focus detection device arranged in the finder optical system. ing.

FIG. 5 is a diagram showing the main configuration of a single-lens reflex camera equipped with this image shift type focus detection device, and FIG. 6 is an optical system for explaining the focus detection operation of the focus detection device of FIG. It is the figure which expanded and showed only a system.

In these figures, 1 is a removable or fixed photographic lens, and 3 is a field lens provided in the vicinity of a pre-fastened image plane (for example, a film plane equivalent surface) 2 of the photographic lens. Reference numerals 4 and 5 are arranged symmetrically with respect to the optical axis L of the taking lens 1, and the regions 1 with different pupils of the taking lens 1 are arranged.
It is a secondary imaging lens for forming two object images based on the light fluxes passing through a and 1b. Reference numerals 6 and 7 denote photoelectric conversion element arrays for detecting the respective object images formed by the secondary imaging lenses 4 and 5. The photoelectric conversion element arrays 6 and 7 are, for example, CCD (Charge Coupied Device).
) Etc.

A field mask 8 is provided in the vicinity of the secondary imaging lenses 4 and 5, and the field lens 3 has openings 8a and 8b of the field mask 8 at different pupil portions 1a of the photographing lens 1. It has a function of forming an image on 1b. 9
Is a reflex mirror (semi-transmissive mirror), which is mirror-processed on the translucent substrate except for the opening area near the optical axis, and is installed obliquely in the shooting optical path during observation and outside the shooting optical path during shooting. You can be saved.

A pentaprism P and an eyepiece E are provided on the reflection side (finder optical system side) of the reflex mirror 9, and a sub-mirror M1, a field lens 3 and an optical path reversal are provided on the transmission side (focus detection optical system side). The mirror M2, the secondary imaging lenses 4 and 5, and the photoelectric conversion element arrays 6 and 7 are arranged in the above order. Further, F is an image plane, on which a silver salt film or an image pickup device is arranged.

In the device as described above, for example, the taking lens 1
6 is extended to the left in FIG. 6 to be in the so-called front focus state, the object images formed on the light receiving surfaces of the photoelectric conversion element arrays 6 and 7 by the secondary imaging lenses 4 and 5 are indicated by arrows. Since it shifts in the direction, it is possible to detect the pre-focus state and its amount by the output change of the photoelectric conversion element arrays 6 and 7 according to the relative shift of the image. Also,
In the rear focus state, each image shifts in the opposite direction to that in the front focus state, so that the rear focus state and the amount thereof can be detected.

FIG. 7 is a diagram for explaining the states of the reflex mirror 9 and the sub mirror M1 in the mirror-down state.

A reflex mirror 9 (not shown in the figure) in the center of the mirror box is attached to a reflex mirror holding frame 10, and the center of the holding frame 10 is a sub-mirror for the light flux passing through the half mirror section. It has an opening 10a for guiding light to M1. The holding frame 10 is rotatably supported by a rotation shaft 11 and is biased by a spring (not shown) to rotate in the direction of arrow A. This rotation is a stopper slightly projected into the mirror box. It is regulated by 12 in a predetermined range.

On the back of the reflex mirror holding frame 10, the above-mentioned sub-mirror M1 for guiding the light beam transmitted through the half mirror section to the focus detection optical system is arranged. The sub-mirror M1 is fixed to the sub-mirror holding frame 13, and the reflex mirror holding frame 1 is fixed by the rotating shaft 14.
It is rotatably supported at 0 and is biased by a spring (not shown) so as to rotate in the direction of arrow B.

Reference numeral 15 is a stopper for restricting the stop position of the sub-mirror holding frame 13, and a cam portion 12a is provided at the end of the rotary shaft of the sub-mirror holding frame 13 so as to move up and down the reflex mirror 9. The cam portion 12a is configured to move along the outer circumference of the guide pin 16.

[0013]

However, in the above-mentioned conventional example, the reflex mirror 9 and the sub mirror M are used.
As the number of operations of No. 1 increases, the rotation shaft support portion and the stopper 12 of the reflex mirror 9 wears, and the rotation shaft support portion and the stopper 15 of the sub mirror M1 wears. There is a problem that the length changes and the focus position detected by the focus detection device deviates from the focus position on the image plane.

FIG. 8 shows a change in optical path length when the stopper 15 of the sub-mirror M1 is worn, and x (= x
a + xb) is the optical path length change amount due to the angle change.

FIG. 9 is a view showing the change in the angle of the sub mirror M1 and the change in the optical path length in an easily understandable manner.

(Object of the Invention) The object of the present invention is obtained by the focus detecting means even if the optical path length to the focus detecting means changes due to an increase in the number of times of operation of the optical member provided in the focus detecting optical system. Another object of the present invention is to provide a focus detection device and a camera capable of eliminating the shift between the focus position and the focus position on the image plane.

[0017]

In order to achieve the above object, the present invention according to claim 1 provides an integrated number of operations of an optical member which operates in association with a focus detection operation or an integrated number corresponding to the integrated number of operations. The relationship with the focus position correction amount associated therewith is stored in advance, and the focus information obtained by the focus detection means is stored in the accumulated number or the accumulated number corresponding thereto and the stored focal position correction amount. According to the present invention as set forth in claims 2-9, the integrating means counts the number of times corresponding to the operation of the optical member, the number of times corresponding to the operation of the optical member, and the focal position correction associated therewith. A focus detecting means is provided which is provided with a storage means for storing a relationship with an amount in advance and a focus position correcting means for correcting the focus information obtained by the focus detecting means based on the information of the integrating means and the storage means. Optical system In the case of a camera, for example, a first semi-transmissive mirror that reflects a part of the light flux that has passed through the taking lens and guides it to the finder optical system side, and a second light flux that guides the remaining light flux that has been transmitted to the focus detection means. The number of times the mirror has been actuated, the number of times of release corresponding to this number of times of operation, or the number of times of auto-loading is counted, and the focus position correction amount at this time is read out from the pre-stored storage means and obtained by the focus detection means. The focus information is corrected.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail based on the illustrated embodiments.

FIG. 1 is a configuration diagram showing a main part of a single-lens reflex camera according to an embodiment of the present invention. The same parts as those in FIGS. 5 to 7 are designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 1, reference numeral 101 is a microcomputer for controlling various operations of the camera, and is provided with a focus determination position changing means 101a and a RAM 101b inside. Reference numeral 102 is a focus detection circuit that detects a focus state based on signals from the photoelectric conversion element arrays 6 and 7, 103 is a mirror drive circuit that drives the rotary shaft 11 of the reflex mirror 9, and 104 is focus adjustment of the taking lens 1. SW1 is a switch that is turned on by the first stroke of the release button, and SW2 is a release switch that is turned on by the second stroke of the release button.

FIG. 2 shows the microcomputer 10 of FIG.
2 is a flowchart showing the operation of No. 1 and will be described below. [Step # 201] It is determined whether or not the switch SW1, which is turned on by the first stroke of the release button, has been turned on by the photographer, and the switch SW1 is turned on to determine step # 201.
Proceed to 102. [Step # 202] Built-in focus position changing means 101
The focus determination position is changed by a.

For example, the focusing position changing means 101a is
The in-focus position correction amount is derived by comparing the in-focus determination position correction value shown in FIG. 4 (a) with the cumulative number of releases stored in the RAM 101b, which is a storage means.

As another example, as shown in FIG. 4 (b), the RAM 101 serving as a focus determination position correction value and storage means.
The focusing position correction amount may be derived by comparing the cumulative number of operations of the reflex mirror 9 stored in b, or further, as shown in FIG. 4 (c),
The focus position correction amount may be derived by comparing the focus determination position correction value and the number of times of automatic loading (AL) integration stored in the RAM 101b serving as a storage unit. [Step # 203] The focus detection circuit 102 detects the focus state based on the signals from the photoelectric conversion element arrays 6 and 7, and proceeds to step # 204. [Step # 204] In step # 203, it is determined whether or not focus detection is possible. If focus detection is not possible, the process proceeds to step # 205. [Step # 205] Since the focus detection circuit 102 could not detect the focus, a publicly known means is used to deal with the AF disabled display or the like.

If focus detection is possible in step # 204, the process proceeds to step # 206. [Step # 206] It is determined whether or not the focus state obtained in the above step # 203 is in-focus, and if in-focus, the process proceeds to the release sequence of step # 211 in FIG. If it is not in focus, step # 20
Move to 7. [Step # 207] The photographing lens 1 is driven via the lens drive circuit 104 based on the focus determination position correction amount selected by the focus position changing unit 101a and the focus information obtained in step # 203. Adjust the focus. [Step # 208] In order to detect the focus state after driving the lens, the focus state is detected by the focus detection circuit 102 based on the signals from the photoelectric conversion element arrays 6 and 7, as in step # 203. And step # 20
Go to 9. [Step # 209] In step # 208, it is determined whether or not focus detection is possible. If focus detection is impossible, the process proceeds to step # 205.

If focus detection is possible in step # 209, the process proceeds to step # 210. [Step # 210] It is determined whether or not the focus state obtained in step # 208 is in focus, and if in focus, the flow shifts to the release sequence of step # 211 in FIG. If it is not in focus, step # 20
Returning to step 3, the same operation is repeated thereafter.

Next, the operation after step # 211 in FIG. 3 in the case of shifting to the release sequence will be described. [Step # 211] It is determined whether or not the switch SW2, which is turned on by the second stroke of the release button, has been turned on by the photographer, and the switch SW2 is turned on to determine step # 2.
Proceed to 212. [Step # 212] The aperture of the lens is narrowed down through the aperture drive circuit (not shown), and the mirror drive circuit is set to 10
The reflex mirror 9 is moved up from the state of FIG. 1 via 3 (withdrawn from the photographing optical path). [Step # 213] [Step # 214] of a known shutter curtain is returned to the open state via a shutter control circuit (not shown),
The reflex mirror 9 is lowered (set to the state shown in FIG. 1). [Step 215] The number of releases is counted by the release number counting means (not shown), and the accumulated number of releases (or the number of times the reflex mirror 9 is operated) is stored in the RAM 101b which is a storage means.

In the case of the configuration in which the number of times of automatic loading is integrated, the number of times is integrated when the film is newly loaded and the film winding to the predetermined position is completed.

When the above operation is completed, the process returns to the previous step # 201.

According to this embodiment, the number of operations of the reflex mirror 9 (sub-mirror M1) is increased, and the change of the optical path length is changed due to the wear of the rotary shaft supporting portion and the stopper for restricting the operation thereof. Even if the focus position detected by the focus detection circuit deviates from the focus position on the film surface, if it is preset by the number of times the reflex mirror 9 is operated (or the number of releases or the number of autoloading). Since the focus information is corrected by the focus determination position correction amount, it is possible to cancel the deviation of the focus position between the focus detection device and the image plane, and even if the number of times the reflex mirror 9 is operated increases, An image with proper focus can always be formed on the image plane.

(Correspondence between Invention and Embodiment) In the above embodiment, the counter (not shown) in the microcomputer 101 corresponds to the integrating means of the present invention, and the RAM 101b in the microcomputer 101 serves as the storing means of the present invention. Correspondingly, the focus position changing means 101a in the microcomputer 101 corresponds to the focus position changing means of the present invention.

The above is the correspondence relationship between each configuration of the embodiment and each configuration of the present invention, but the present invention is not limited to the configurations of these embodiments, and the functions shown in the claims,
It goes without saying that any structure may be used as long as the functions of the embodiments can be achieved.

(Modification) The present invention is applied to a single-lens reflex camera by way of example. However, the present invention is not limited to this, and a focus detection device having an optical member for changing the luminous flux and the focus detection device. The present invention can be applied even to an optical device equipped with a detection device.

[0033]

As described above, according to the present invention,
For example, in the case of a camera, which is provided in the focus detection optical system, the first semi-transmissive mirror that reflects a part of the light flux that has passed through the taking lens and guides it to the finder optical system side and the remaining light flux that has passed through the focus detection are detected. The number of operations of the second mirror guided to the means, the number of times of release corresponding to the number of operations, or the number of times of auto-loading is counted, and the focus position correction amount at this time is read from the storage means that is stored in advance, and the focus is adjusted. The position changing means corrects the focus information obtained by the focus detecting means.

Therefore, even if the optical path length to the focus detecting means changes due to an increase in the number of operations of the optical members provided in the focus detecting optical system, the focus position and the image plane obtained by the focus detecting means are changed. It is possible to eliminate the shift of the in-focus position of.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a main part of a single-lens reflex camera according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a part of the operation of the camera of FIG.

FIG. 3 is a flowchart showing a continuation of the operation of FIG.

FIG. 4 is a diagram showing an example of data used for changing a focus position by a focus position changing means in the embodiment of the present invention.

FIG. 5 is a diagram showing a main part configuration of a conventional single-lens reflex camera including an image shift type focus detection device.

6 is a diagram in which only an optical system is expanded and shown in order to explain a focus detecting operation by the focus detecting device of FIG.

7 is a sectional view showing a single-lens reflex camera equipped with the optical system of FIG.

8 is a diagram showing a change in optical path length when the stopper of the sub-mirror in FIG. 4 is worn.

9 is a diagram showing an angle change and an optical path length change amount of the sub mirror of FIG. 4 in an easily understandable manner.

[Explanation of symbols]

 1 Photographic Lens 9 Reflex Mirror 11 Rotation Axis M1 Sub Mirror 101 Microcomputer 101a Focus Position Changing Means 101b RAM 102 Focus Detection Circuit 103 Mirror Drive Circuit SW1 Switch SW2 Release Switch

Claims (9)

[Claims] 1. A relationship between an integrated number of operations of an optical member that operates in association with a focus detection operation or an equivalent number of operations and a focal position correction amount associated therewith is stored in advance, and the focus detection means stores the relationship. A focus detection device, wherein the focus information obtained by the above is corrected based on the number of times of integration or the number of times of integration corresponding thereto and the stored focus position correction amount. 2. A focus detecting device comprising a focus detecting means for detecting a focus state of an optical system and a focus optical system comprising an optical member which operates in association with a focus detecting operation, comprising: Alternatively, an integrating means for counting the number of times corresponding thereto, a memory means for storing in advance the integrated number of operations of the optical member, or a relationship between the integrated number corresponding thereto and the amount of focus position correction associated therewith, and the focus detection A focus detection apparatus comprising: a focus position correction unit that corrects the focus information obtained by the means based on the information of the integration unit and the information of the storage unit. 3. The focus detecting device according to claim 2, wherein the optical member provided in the focus optical system is a light beam direction changing means for changing the direction of the light beam. 4. A camera provided with a focus detecting means for detecting a focus state of a photographing lens and a focus optical system having an optical member which operates in association with a focus detecting operation, wherein In the focus detection means, there is provided an integration means for counting the number of times corresponding to the above, a storage means for storing in advance the integration times of the operation of the optical member or a relationship between the integration times corresponding thereto and the amount of focus position correction associated therewith. A camera provided with focus position correction means for correcting the focus information obtained as described above based on the information of the integration means and the information of the storage means. 5. The integrating means is means for counting the number of times the optical member has been actuated itself, and the storage means stores in advance the relationship between the number of times the optical member has been actuated and the focal position correction amount associated therewith. The camera according to claim 4, wherein the camera is means. 6. The integrating means is means for counting the number of times of release and setting the number of times to the number of times corresponding to the operation of the optical member, and the storage means stores the number of times of releasing and the focal position associated therewith. The camera according to claim 4, wherein the camera is a means that stores a relationship with a correction amount in advance. 7. The accumulating means counts the number of times of auto-loading, and makes this number the number of times corresponding to the operation of the optical member, and the storage means accompanies the number of times of the auto-loading and the number of times of accumulating. The camera according to claim 4, wherein the camera is a means that stores a relationship with a focus position correction amount in advance. 8. The optical member provided in the focusing optical system includes a first semi-transmissive mirror that reflects a part of the light flux that has passed through the taking lens and guides it toward the finder optical system, and the remaining light flux that has been transmitted. 8. The camera according to claim 4, which is a second mirror that guides the light to the focus detection means. 9. The focus detecting means is means for performing focus detection based on a relative positional relationship between two images formed by passing through different pupil regions of a photographing lens. Or the camera according to 7.