JP2004045728A - Camera, focusing device and focusing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a camera, a focusing device and a focusing method which efficiently discriminate a plurality of points within an image and executing focusing at a high speed. <P>SOLUTION: Object light passing through a photographing lens 11 is divided into two luminous fluxes passing through different areas within a photographing image in a focus detection optical system 25 and a pair of image signals are outputted from the two luminous fluxes. From the object light passing through the photographing lens 11, a plurality of the luminous fluxes of different optical path lengths are formed in an area sensor 22 and the image signals based on the plurality of the luminous fluxes are outputted. Then, according to the output of a sensor array 26 and the area sensor 22, focusing is detected. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a camera focus detection device, and more particularly to an improvement in a so-called TTL AF camera that adjusts a focal position of a photographing lens using an image signal obtained through the photographing lens. .
[0002]
[Prior art]
Conventionally, the TTL AF has the advantage of using a light passing through a photographing lens, so that there is no parallax and high-precision focusing by feedback control is possible, and it has been applied to a lens-interchangeable camera. .
[0003]
However, if the photographing lens is located far away from the in-focus position, correct focus control may not be performed, for example, the image of the subject may be blurred or the image may protrude from the image sensor.
[0004]
In recent years, with the development of so-called multi-point (multi) AF technology, various devices for selecting a focusing point from many points on a screen have been proposed (for example, Japanese Patent No. 3253398 by the present applicant). However, as the number of points for focusing increases, the range of focus detection at each point tends to be limited.
[0005]
[Problems to be solved by the invention]
By the way, in many interchangeable lens cameras or single-lens reflex cameras, a so-called phase difference AF, which detects a focus position using two image signals incident from different fields of view of a photographing lens, has become mainstream. I have. In the phase difference AF, the displacement of a lens in the optical axis direction is converted into an image position change in a direction perpendicular to the optical axis direction and detected.
[0006]
That is, it is possible to detect a wider range by arranging many sensors in a direction orthogonal to the optical axis direction of the lens. However, in the case of multi-AF, since the sensors for different points are arranged on the same axis, the detection range tends to be narrow.
[0007]
In addition, when the number of detection points increases, it is necessary to detect points in the screen that do not originally need to detect focus, resulting in a useless time lag.
[0008]
Thus, it is very difficult to combine the multi-AF operation with a wide focusing range.
[0009]
Therefore, the present invention has been made in view of the above situation, and provides a camera, a focusing device, and a focusing method that can efficiently discriminate a plurality of points on a screen and perform focusing at high speed. It is.
[0010]
[Means for Solving the Problems]
That is, the present invention divides subject light that has passed through a photographing lens into two light beams that pass through different regions in a photographing screen, and outputs a pair of image signals from the two light beams; Second image detecting means for forming a plurality of light fluxes having different optical path lengths from subject light passing through the photographing lens, and outputting image signals based on the plurality of light fluxes; and outputs of the first and second image detecting means And focus detection means for performing focus detection in accordance with
[0011]
Further, the present invention further comprises a first image detecting means for dividing the subject light passing through the photographing lens into two light beams passing through different regions in the photographing screen, and outputting a pair of image signals from the two light beams; A second image detecting means for forming a plurality of light beams having different optical path lengths from subject light passing through the photographing lens and having an area sensor for outputting an image signal based on the plurality of light beams; the first and second image detecting means; The image processing apparatus further includes a focus detection unit that performs focus detection in accordance with an output of the image detection unit, and an exposure control unit that performs exposure control based on an image signal output from the area sensor.
[0012]
The first step of dividing the subject light passing through the photographing lens into two light beams passing through different regions in the photographing screen, and outputting a pair of first image signals from the two light beams; A second step of forming a plurality of luminous fluxes having different optical path lengths from subject light passing through the photographing lens and outputting a second image signal based on the plurality of luminous fluxes; and outputting the first and second image signals And a third step of performing focus detection in accordance with
[0013]
Further, the present invention provides a plurality of re-imaging optical units having different focal lengths for forming an image with different optical path lengths, an image detecting unit for outputting an image signal based on the plurality of light beams, and the image detecting unit. And a focus detection unit that performs focus detection according to the output.
[0014]
In the focusing apparatus according to the aspect of the invention, the subject light having passed through the photographing lens is divided into two light beams passing through different regions in the photographing screen by the first image detecting means, and a pair of image light beams is formed from the two light beams. A signal is output. A plurality of light fluxes having different optical path lengths are formed from the subject light passing through the photographing lens by a second image detecting means, and an image signal based on the plurality of light fluxes is output. Then, in accordance with the output of the first and second image detecting means, focus detection is performed by the focus detecting means.
[0015]
Further, in the camera of the present invention, the subject light passing through the taking lens is divided into two light beams passing through different regions in the photographing screen, and the first image detecting means converts the two light beams into a pair of images. A signal is output. Further, in the second image detecting means having the area sensor, a plurality of light beams having different optical path lengths are formed from the subject light passing through the photographing lens, and an image signal based on the plurality of light beams is output. Focus detection is performed by the focus detection means in accordance with the outputs of the first and second image detection means, and exposure control is performed by the exposure control means based on the image signal output from the area sensor. Is
[0016]
According to the focusing method of the present invention, the subject light passing through the photographing lens is divided into two light beams passing through different regions in the photographing screen, and a pair of first image signals is formed from the two light beams. Is output. Next, a plurality of light beams having different optical path lengths are formed from the subject light passing through the photographing lens, and a second image signal based on the plurality of light beams is output. Then, focus detection is performed according to the output of the first and second image signals.
[0017]
In the focusing apparatus according to the present invention, the plurality of re-imaging optical units having different focal lengths form images with different optical path lengths, and the image detecting unit outputs an image signal based on the plurality of light beams. . Then, focus detection is performed by the focus detection means in accordance with the output of the image detection means.
[0018]
As a result, in addition to the phase difference AF used in many interchangeable lens type cameras and single-lens reflex cameras, using the output of a sensor for determining contrast, a position suitable for focusing is instantly detected, The direction of focusing can be determined at high speed.
[0019]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0020]
FIG. 1 shows a configuration of an embodiment of the present invention, and shows an example in which the present invention is applied to a single-lens reflex camera with interchangeable lenses.
[0021]
In FIG. 1, the camera comprises a camera body 1 and a lens barrel 2 detachably attached to the camera body 1. The lens barrel 2 includes a photographing lens 11 for guiding a photographing light beam from a not-shown subject, and a motor 12 for driving the photographing lens 11 under the control of a CPU 27 described later.
[0022]
On the other hand, the camera body 1 has a main mirror (quick return mirror) 15 that reflects and transmits light that has entered through the photographing lens 11. The light reflected by the main mirror 15 reaches a photographer's eye 20 through a pentaprism 17 and an eyepiece 18 via a focusing screen 16. Further, a compound eye lens 21 and an area sensor 22, which will be described later, are arranged above the eyepiece lens 18 and near the pentaprism 17. It is desirable that the focusing screen 16 has a low diffusivity.
[0023]
The main mirror 15 is constituted by a half mirror, and a part of the light passes through the main mirror 15 and is reflected by the sub-mirror 24 downward in the drawing, and is guided to the focus detection optical system 25. In the focus detection optical system 25, the subject image is divided into two, and the output is supplied to the sensor array 26. The focus detection optical system 25 and the sensor array 26 constitute a first image detection unit. The output of the sensor array 26 is supplied to an arithmetic and control unit (CPU) 27 including a one-chip microcomputer or the like. The CPU 27 is supplied with the output of the area sensor 22, and further controls the driving of the motor 12, the image processing circuit 31, the main mirror 15, and the sub mirror 24.
[0024]
When the main mirror 15 and the sub-mirror 24 are rotated in the direction indicated by the arrow A under the control of the CPU 27, a photographic light beam from a subject (not shown) is imaged on the image sensor 29. The signal obtained by the image sensor 29 is converted into a digital signal by the A / D converter 30 and output to the image processing circuit 31. Then, when processing such as compression is performed in the image processing circuit 31, the image can be recorded in the memory 32 as a digital image signal.
[0025]
The CPU 27 detects a photographer's camera operation and sequentially controls image processing including focusing, mirror control, and exposure control.
[0026]
In such a configuration, the light incident through the photographing lens 11 is reflected upward by the main mirror 15 in FIG. 1 and forms an image on the focusing screen 16. Thereby, the photographer (eye) 20 can enjoy photographing while checking the photographic composition by the pentaprism 17 and the eyepiece 18.
[0027]
The light transmitted through the main mirror 15 is reflected by the sub mirror 24 and guided to the focus detection optical system 25.
[0028]
FIG. 2A is a diagram showing a detailed configuration of the focus detection optical system 25 and its peripheral portion. The focus detection optical system 25 includes a field mask 25a, a condenser lens 25b, a mirror 25c, and a separator lens 25d. The focus detection optical system 25 divides a subject image into two, and changes the extension position of the lens at right angles. To the direction you want. The sensor array 26 detects the relative position of the two divided images.
[0029]
The output of the sensor array 26 is converted into a digital image signal by an A / D converter built in the CPU 27. Thus, the relative position of the two images is determined. If the motor 12 is controlled using the result, focus control of the photographing lens 11 can be performed.
[0030]
In this state, when the main mirror 15 is rotated in the direction indicated by arrow A and retracted out of the optical path, a subject image is formed on the image sensor 29. Therefore, by performing appropriate exposure control depending on the brightness of the subject, an image in focus and exposure can be obtained.
[0031]
FIG. 2B is a view for explaining the focus detection optical system 25 described above and is shown without bending the optical path by a mirror.
[0032]
That is, light (two images) passing through different optical paths 11a and 11b of the photographing lens 11 is incident on the sensor arrays 26a and 26b by the functions of the condenser lens 25b and the separator lens 25d. When the photographing lens 11 is moved in the optical axis direction (the direction of arrow B in the drawing), the distance between the pair of separator lenses 25d does not change, so that the subject image position changes in the direction in which the sensor arrays 26a and 26b are arranged.
[0033]
Such a function determines the positional relationship between the two images when the photographing lens 11 is at the optimal position, so that the focusing lens may be controlled so as to achieve the positional relationship. If the focusing range of the lens is widened, it will be out of the range of the sensor arrays 26a and 26b, and if it exceeds this range, it is difficult to focus, and the CPU 27 of the camera determines which one to control the focusing lens. Impossible. This may limit the speed of focusing.
[0034]
On the other hand, if the length of the sensor array is increased, as shown in FIG. 3, the specification of a so-called multi-AF camera having a focusing range at a plurality of points (L, C, R) 31 in the screen 30 is realized. It becomes difficult. This is for the following reason.
[0035]
That is, as shown in FIG. 3, in order to detect three points (L part, C part, and R part), as apparent from FIG. And three pairs of L, C, and R corresponding to the sensor array 26 are required. For this reason, as shown in FIG. 2C, when the sensor array 26C at the center (C) is made longer, it is difficult to arrange the left (L) and right (R) sensor arrays 26L and 26R. This is because it may not be possible to dispose the sensor.
[0036]
In the present invention, the area sensor 22 as shown in FIG. 1 is disposed at a position where the focusing screen 16 is viewed through the compound eye lens 21 and the pentaprism 17 so that the image on the focusing screen 16 is focused. Or which one is deviated. The compound eye lens 21 is a re-imaging unit that re-combines the image formed on the focusing screen 16 with the area sensor 22.
[0037]
As shown in FIG. 4A, the compound eye lens 21 integrally formed is divided into three, 21a, 21b, and 21c, and the area monitored by the area sensor via each of the lenses 21a, 21b, and 21c. Are 22a, 22b and 22c. When this area sensor is viewed from the front, it is as shown in FIG.
[0038]
The central portions of the sensors 22a, 22c and 22b monitor an area 33 in the screen 30 shown in FIG. 3 via the lenses 21a, 21c and 21b. The compound eye lens 21 and the area sensor 22 constitute a second image detecting unit. Since the sensor 22b has a larger area in the vertical direction than the sensors 22a and 22c, it monitors a wider area 23 in the screen. Therefore, if the amount of light incident on the sensor 22b is added, the same effect as that of the average photometry can be obtained, which can be used for the exposure control of the camera.
[0039]
FIG. 5 is a block diagram showing a configuration of the above-described area sensor and peripheral portions.
[0040]
In FIG. 5, the shaded portions indicate the light receiving surfaces (pixels) 37b1, 37b2, 37c1, 37c2, 37d1, and 37d2 of the area sensor. Photocurrents generated from these pixels 37b1, 37b2, 37c1, 37c2, 37d1, 37d2 are converted into voltage signals by integration circuits 38b1, 38b2, 38c1, 38c2, 38d1, 38d2 provided for each pixel.
[0041]
Regarding the magnitude relation of the light incident on each pixel, the terminal of the switch 39 is switched by the switch (SW) control circuit 40 sequentially from the CPU 27. That is, terminals B1, B2, C1, C2, D1, and D2 connected to the integration circuits 38b1, 38b2, 38c1, 38c2, 38d1, 38d2 are selected, read by the A / D conversion circuit 41, and converted into image signals. Can be
[0042]
On the other hand, the anode side of each of the pixels 37b1, 37b2, 37c1, 37c2, 37d1, 37d2 is all connected to the current mirror circuit 43, so that the addition result of all pixels flows into the compression diode 44. Therefore, if the switch 39 for inputting to the A / D conversion circuit 41 is connected to the terminal A, the CPU 27 can detect the addition result of all pixel currents.
[0043]
As described above, all the pixel signals of the portion 22b in FIG. 4B can be added to be used for exposure control as average photometric data. In other words, the sensor 22 is effectively used as a sensor that also serves as a focusing sensor and an exposure control sensor. When each pixel is treated independently, it can be determined whether or not the contrast of each area is appropriate for focusing.
[0044]
Here, a focus position detection method using pixel signals of the respective areas 22a, 22b, 22c of the area sensor 22 will be described with reference to FIG.
[0045]
As shown in FIG. 6A, lenses 21a, 21b, and 21c are arranged in front of the area sensors 22a, 22b, and 22c at different positions in the optical axis direction.
[0046]
As shown by the solid ray in FIG. 6B, in a state where the lens 21c has just focused on the focusing screen 16 and is focused on the light receiving surface 22, the lenses 21b and 21a are displaced. Because of the arrangement, the image on the focusing screen 16 cannot be correctly formed on the light receiving surface 22. An image formed by the lens 21b that forms a farther object is blurred and has no image contrast, and an image formed by a lens 21a that forms a farther object is further blurred and the image contrast is further reduced. .
[0047]
Conversely, when the contrast of the image by the lens 21c is lower than the contrast of the image by the lens 21a, as indicated by the broken-line light, the focusing screen 16 which is originally at the position corresponding to the focus plane is closer to the sensor. It is considered that the position of the shifted 16F is in focus. In order to return the so-called rear focus position to the position of 16, the photographing lens 11 needs to be further retracted as shown in FIG. That is, it is necessary to move the photographing lens from the position of the photographing lens shown in FIG. 7A in the direction of the arrow B1 shown in FIG. 7B. Actually, the image formed by the lens 21b on the focusing screen 16 is formed on the light receiving surface 22 exactly.
[0048]
In FIG. 6, the lenses 21a to 21c and the area sensors 22a to 22c are expressed as monitoring different points on the focusing screen 22, but actually, as shown in FIG. It is assumed that the same subject image is detected with a view to a portion corresponding to the region 33 in FIG. The L, C, and R portions in FIG. 3 correspond to the L, C, and R portions in FIG. 4B, respectively.
[0049]
Next, referring to the flowchart of FIG. 8, as described above, the focus position and the contrast of the subject are determined by using the image signal of the area sensor provided separately from the phase difference AF sensor, and the high speed is determined. Will be described.
[0050]
First, steps S1 to S3 are steps for detecting the contrast of the images of the area sensors 22a to 22c configured as described above. That is, in step S1, a low contrast portion is detected from the area sensor 22a. Next, in step S2, a low contrast portion is detected from the area sensor 22b, and in step S3, a low contrast portion is detected from the area sensor 22c.
[0051]
As described repeatedly in the description of FIG. 6, since the lenses 21a to 21c are displaced in the optical axis direction, even if the photographing lens is stopped at a blurred position with respect to the imaging surface, the area sensor An image that is not greatly blurred is formed on any of 22a to 22c. Therefore, if an image with high contrast is present in any of the sensors 30a to 30c, focusing should be basically possible.
[0052]
However, when the contrast is not detected by any of the sensors, it is considered that an object having no contrast, such as a white wall or the empty area sensors 22a to 22c, is being monitored. In such a case, focus detection is not possible with either the phase difference AF or the contrast AF, so it is preferable to issue a warning early to inform the user.
[0053]
Accordingly, in step S4, points (for example, corresponding to the L, C, and R portions in FIG. 3) at which the low contrast is detected are detected in any of the area sensors 22a, 22b, and 22c. . Next, in step S5, it is first determined whether or not the portion C has low contrast. Here, if the section C is not low contrast, the process proceeds to step S13, and if it is low contrast, the process proceeds to step S6.
[0054]
Then, in step S6, it is determined whether or not the R portion has low contrast. Here, when the R portion is not low contrast, the process proceeds to step S9, and when the R portion is low contrast, the process proceeds to step S7.
[0055]
If it is determined in step S7 that the L portion has low contrast, it is determined that all the points of the C portion, the R portion, and the L portion have low contrast, so that useless lens driving is not performed. A warning is issued immediately after shifting to S8.
[0056]
If it is determined in step S6 that the R portion is not low contrast, the process proceeds to step S9, where the sensor array 26R performs focusing. Next, in step S10, it is determined again whether or not the L portion has low contrast. Here, if the L portion has low contrast, the process proceeds to step S12; otherwise, the process proceeds to step S11.
[0057]
In step S11, focusing is performed by the sensor array 26L. Next, in step S12, focusing is performed at any point indicating a short distance between the L portion and the R portion, and then the process proceeds to step S18.
[0058]
If it is determined in step S5 that the portion C is not low contrast, the process proceeds to step S13, and the sensor array 26C focuses on the phase difference method (see FIG. 2B). Then, in step S14, it is determined whether or not focusing by the phase difference method is impossible. Here, if it is impossible, the process proceeds to step S15, and if not, the process proceeds to step S18.
[0059]
By the way, even if it is determined that only the electrical calculation in the CPU 27 is on the order of milliseconds or less, if the control of the lens driving amount is in between, the time lag immediately becomes on the order of 0.1 second, and the operability is significantly deteriorated. Therefore, the present invention reduces the number of determinations and detections while driving the lens as much as possible and achieves high speed. In the above-described steps S1 to S3, a point which is not suitable for focusing is determined in advance. Even in a situation where the phase difference AF cannot be performed by the focus position determination described in the above section, the lens driving direction is determined.
[0060]
Steps S14 to S17 implement the contrivance. That is, if focusing by the phase difference method is impossible in step S14, the process proceeds to step S15, and the contrast of the area sensor 22 described in FIG.
[0061]
Then, the lens driving direction is determined according to the result of this determination. That is, when the blur of the area sensor 22a is larger than the blur of the area sensor 22c, the process proceeds to step S16 and the lens is driven in the extending direction. On the other hand, when the blur of the area sensor 22c is larger than the blur of the area sensor 22a, the process proceeds to step S17, and the lens is driven in the retracting direction.
[0062]
In this manner, high-speed focusing can be performed without the need for detection driving (determining the direction of focusing by slightly moving the lens), which is sometimes necessary in the phase difference AF. When the lens driving direction is determined, the flow shifts to step S13 to perform focusing by the phase difference AF method.
[0063]
Further, it can be determined in the above step S4 whether or not the central portion (C portion) where the existence probability of the subject is highest has low contrast. Therefore, at the time of low contrast, the process proceeds to step S6, and focusing using the R portion or the L portion is performed.
[0064]
Since it is determined in step S4 whether or not the above-described R and L portions are positioned for focusing, if there is no contrast, the steps of focus detection in steps S9 and S11 are skipped, resulting in waste. The speed is increased without performing any complicated processing.
[0065]
When either the left or the right is selected, one or a short-distance object that has been detected in step S12 is prioritized and the selected focus is performed.
[0066]
When focusing is completed in this way, the result of adding the pixel outputs of the area sensor 22b is determined in step S18. Then, an exposure control method is determined in step S19 according to the result. Further, in step S20, shooting is performed using the controlled focus and exposure control method, and a series of sequences ends.
[0067]
Steps S5, S6, and S7 are for determining whether the in-focus position is at the center, right, or left of the screen.
[0068]
As described above, according to the present embodiment, focus control can be performed at higher speed using the sensor for exposure control.
[0069]
Further, in the present embodiment, for simplification, the output obtained by adding the pixels of the area sensor 22b for the exposure control is simplified for average photometry. It goes without saying that control may be performed such that several pixels are grouped together and weighted.
[0070]
According to the above embodiment of the present invention, the following configuration can be obtained.
[0071]
That is,
(Additional Item 1) First image detecting means for detecting a pair of image signals by two light beams passing through different regions of the photographing lens;
Second image detecting means for detecting the light passing through the taking lens by changing the optical path length,
Control means for adjusting the focus of the taking lens based on the output results of the first and second image detection means;
A camera comprising:
[0072]
(Additional Item 2) The camera according to Additional Item 1, wherein the second image detecting means includes a plurality of lenses having different focal positions and an area sensor.
[0073]
(Additional Item 3) The second image detecting means has an adding circuit for adding the output of each pixel, and further includes an exposure controlling means for controlling the exposure of the camera from the output of the adding circuit. 2. The camera according to claim 1, wherein the camera is characterized in that:
[0074]
(Additional Item 4) First image detecting means for detecting a pair of image signals by two light beams passing through different fields of view of the taking lens;
A second image detecting means having a mode for adding and outputting the pixel outputs and a mode for independently detecting each pixel output, and detecting a third light flux passing through the photographing lens;
Control means for adjusting the focus of the taking lens according to the outputs of the first and second image detection means;
A camera comprising:
[0075]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a camera, a focusing device, and a focusing method capable of efficiently determining a plurality of points in a screen and performing high-speed focusing.
[Brief description of the drawings]
FIG. 1 is a view showing a configuration of a first embodiment of the present invention, and is a diagram showing an example in which the present invention is applied to a single-lens reflex camera with interchangeable lenses.
2A is a diagram illustrating a detailed configuration of a focus detection optical system 25 and a peripheral portion thereof, FIG. 2B is a diagram illustrating the focus detection optical system 25, and is a diagram illustrating the focus detection optical system 25 without bending an optical path by a mirror; (C) is a diagram showing an example of the arrangement of the center, left, and right sensor arrays.
FIG. 3 is a diagram showing an example of an area in a screen 30.
4A is a diagram illustrating a relationship between a compound eye lens and an area sensor, and FIG. 4B is a diagram illustrating a relationship between an area sensor and an L portion, a C portion, and an R portion.
FIG. 5 is a block diagram showing a configuration of an area sensor and peripheral portions.
FIG. 6 is a diagram illustrating a focus position detection method using pixel signals of respective areas 22a, 22b, and 22c of the area sensor 22.
FIG. 7 is a diagram illustrating a focus surface and a position of a photographing lens.
FIG. 8 is a flowchart illustrating an operation of determining a focus position and a contrast of a subject and performing high-speed AF in the camera according to the embodiment of the present invention.
[Explanation of symbols]
1 camera body,
2 lens barrel,
11 shooting lens,
15 Main mirror (quick return mirror),
16 Focusing screen,
17 Penta prism,
18 eyepieces,
21, 21a, 21b, 21c compound eye lens,
22, 22a, 22b, 22c area sensor,
24 submirrors,
25 focus detection optical system,
25a field mask,
25b condenser lens,
25c mirror,
25d separator lens,
26, 26a, 26b, 26C, 26L, 26R sensor array,
27 arithmetic control means (CPU),
29 image sensor,
30 A / D converter,
31 image processing circuit,
32 memory.

Claims (20)

First image detecting means for dividing subject light passing through the photographing lens into two light beams passing through different regions in the photographing screen and outputting a pair of image signals from the two light beams;
Second image detection means for forming a plurality of light beams having different optical path lengths from subject light passing through the photographing lens, and outputting an image signal based on the plurality of light beams;
Focus detection means for performing focus detection according to the output of the first and second image detection means;
A focusing device comprising: 2. The focusing apparatus according to claim 1, wherein the second image detecting means includes a plurality of re-imaging optical means having different focal lengths for forming images with different optical path lengths. The focusing device according to claim 2, wherein the second image detecting means is provided in an optical finder for visually recognizing a subject image. 4. The focusing apparatus according to claim 3, wherein the re-imaging optical unit forms a plurality of light beams having different optical path lengths from a subject image formed for an optical finder. 4. The optical finder according to claim 3, wherein the second image detecting means is provided on the optical viewfinder having an image forming surface on which the subject image is formed and having an optically diffusive property. 5. The focusing device according to 4. The focusing device according to claim 3, wherein the second image detection unit is disposed near an eyepiece provided in the optical viewfinder. 7. The apparatus according to claim 1, wherein the focus detecting unit detects a direction in which the focus is shifted by comparing image signals having different optical path lengths output from the second image detecting unit. Focusing device. The focusing apparatus according to claim 1, wherein the focus detection unit detects a position of a subject in a screen based on an image signal output from the second image detection unit. The first image detecting means sets a region to which the two light beams belong as one detection region and selects one of the detection regions provided in the screen according to the detected position of the subject in the screen. 9. The focusing device according to claim 8, further comprising a selection unit for selecting a detection area to be used. The subject light to the first image detecting means is one of the subject lights passing through the taking lens and divided by the optical path dividing means, and the subject light to the second image detecting means is the other of the divided light. The focusing device according to claim 1, wherein the object light is a subject light. A camera comprising the focusing device according to claim 1. First image detecting means for dividing the subject light passing through the photographing lens into two light beams passing through different regions in the photographing screen and outputting a pair of image signals from the two light beams;
A second image detecting unit that forms a plurality of light beams having different focus image positions from subject light passing through the photographing lens and has an area sensor that outputs an image signal based on the plurality of light beams;
Focus detection means for performing focus detection according to the output of the first and second image detection means, exposure control means for performing exposure control based on an image signal output from the area sensor,
A camera comprising: 13. The camera according to claim 12, further comprising an adding unit that adds an image signal output from the area sensor and outputs the added image signal to the exposure control unit. 14. The camera according to claim 12, wherein the area sensor outputs an image signal for each of the plurality of light beams. 15. The camera according to claim 14, wherein the exposure control means performs exposure control based on an output of an image signal of a wide light receiving area in each of the light receiving areas corresponding to the plurality of light beams. A first step of dividing the subject light passing through the photographing lens into two light beams passing through different regions in the photographing screen, and outputting a pair of first image signals from the two light beams;
A second step of forming a plurality of luminous fluxes having different optical path lengths from subject light passing through the photographing lens, and outputting a second image signal based on the plurality of luminous fluxes;
A third step of performing focus detection in accordance with the output of the first and second image signals;
A focusing method comprising: The focusing method according to claim 15, wherein the plurality of light beams having different optical path lengths are formed by a plurality of re-imaging optical systems having different focal lengths. A plurality of re-imaging optical means having different focal lengths for imaging with different optical path lengths,
Image detection means for outputting an image signal based on the plurality of light fluxes,
Focus detection means for performing focus detection according to the output of the image detection means,
A focusing device comprising: 19. The focusing device according to claim 18, wherein the re-imaging optical unit and the image detecting unit are provided in an optical finder for visually recognizing a subject image. 20. The focusing apparatus according to claim 19, wherein the re-imaging optical unit forms a plurality of light beams having different optical path lengths from a subject image formed for an optical finder.

Images