JP2002014275A - Camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a camera with an automatic focusing function of accurately deciding a main object, irrespective of a zooming position and a distance up to the object, and accurately finding the range of the object, and further, focusing on the object. SOLUTION: As for the camera, a two-dimensional detection limit area required at operating at a 2nd timing in accordance with the range finding result at the 1st timing is decided by a CPU 1 based on the outputs of sensor arrays 2a and 2b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a camera having an autofocus function for detecting a main subject in a photographing screen and performing focusing.

[0002]

2. Description of the Related Art In general, a camera having an auto-focus function is configured to measure a distance of a subject located at the center of a screen and focus on the subject in accordance with the distance of the subject. In such a case, it becomes difficult to focus on a subject existing in the periphery of the screen. In view of this problem, there has been proposed a technology relating to an apparatus that also performs distance measurement on a subject existing outside the center of the screen.

However, since the main subject is generally more likely to be located at the center of the screen than at the periphery of the screen, the method of detecting the main subject based on the determination in consideration of the position in the screen is more suitable for focusing. It can be said that the accuracy becomes higher.

However, in a compact camera, the optical paths of the finder optical system and the distance measuring optical system are different.
Particularly at short distances, the center of the finder and the center of the distance measurement sensor often differ due to parallax (hereinafter, referred to as parallax).

[0005] Therefore, even if it is the center of the screen, the corresponding sensor position may be shifted depending on the distance. As a technique made in view of such a problem, Japanese Patent Application Laid-Open No. 8-2
There is a technique disclosed in Japanese Patent Application Laid-Open No. 9235/1994, and in this technology, a device is used in which a distance measurement area is switched in a so-called macro mode.

[0006]

However, in the above prior art, it is assumed that the macro mode is employed. However, even in a camera which does not employ the macro mode, the above-described problem due to parallax cannot be avoided. Was something.

In recent years, a compact camera is often equipped with a zoom lens. In such a case, the angle of view may not coincide with the range in which the distance can be measured. The need had arisen.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to accurately determine a main subject regardless of the zooming position and the distance to the subject, and to accurately measure the main subject. It is an object of the present invention to provide a camera having an autofocus function for performing focusing and focusing.

[0009]

In order to achieve the above object, according to a first aspect of the present invention, there is provided a finder for observing a photographic screen, and the finder is disposed on a different optical path from the finder. A distance measuring means having a two-dimensional detection area in a screen, and a two-dimensional moving means for operating the distance measuring means at a second timing according to a result of operating the distance measuring means at a first timing. And a determining means for determining a specific detection restricted area.

Further, in a second aspect, in the first aspect, the distance measuring means is provided with a passive method for measuring a distance using an image signal of the object and a distance measuring means irrespective of the image of the object. The distance measurement is performed by at least one of an active method that measures a distance in accordance with a signal component from the subject when the distance light is projected, and the distance measurement method at the first timing and the active method that measures the distance. A camera is provided, wherein the distance measurement method at the second timing is different.

In a third aspect, a finder means for observing a photographing screen, and a distance measuring means disposed on an optical path different from the finder means and having a detection area in a direction in which the finder means is aligned with the photographing screen. And the distance measurement results in a plurality of predetermined regions of the distance measuring means are sequentially compared with predetermined values, and when it is determined that the comparison results are substantially equal, a predetermined range around the area is determined. And a determination means for determining a focus position based on a comparison of the distance measurement results.

According to a fourth aspect, there is provided the camera according to the third aspect, wherein the predetermined area is determined by a zooming position.

According to the above-mentioned first to fourth aspects, the following operations are provided.

That is, in the first aspect of the present invention, the photographing screen is observed by the finder means, and the distance measuring means disposed on an optical path different from the finder means two-dimensionally displays the photographing screen in the photographing screen. A two-dimensional detection limit area when the distance measuring means is operated at the second timing according to the result obtained when the distance measuring means is operated at the first timing by the determining means. Is determined.

According to a second aspect, in the first aspect, the distance measuring means is different in the distance measuring method at the first timing from the distance measuring method at the second timing. Have been.

Further, in the third aspect, the photographing screen is observed by the finder means, and the detection area is arranged in the direction in which the photographing screen of the finder means is arranged by the distance measuring means arranged on an optical path different from the finder means. Defined, by the determination means, the distance measurement results in the plurality of predetermined areas of the distance measurement means are sequentially compared with predetermined predetermined values, respectively,
When it is determined that the comparison results are substantially equal, distance measurement is performed by the distance measuring means in a predetermined range centered on the area, and a focus position is determined based on the comparison of the distance measurement results.

According to a fourth aspect, in the third aspect, the predetermined area is determined by a zooming position.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

First, a first embodiment of the present invention will be described.

FIG. 1C is an external configuration diagram of the camera according to the first embodiment.

As shown in FIG. 1, a photographing lens 7, a finder objective unit 23, a strobe light emitting unit 24, and a distance measuring window 25 are provided at least on the front surface of the camera 100, and a release button is provided on the upper surface. 101 is provided.

In such a configuration, as shown in FIG. 1D, a finder objective lens 50 and a distance measuring lens 51 are provided.
The viewfinder angle of view and the distance measurement range are different depending on the parallax S between. In the figure, the area indicated by diagonal lines can be measured, but is out of the shooting range and is therefore inappropriate for distance measurement at the time of focusing.

FIG. 1A shows the relationship between the shooting screen and the distance measurement area when the distance to the subject is L2. Here, an area sensor is used as a distance measuring sensor, and x,
It is assumed that the range that can be measured in the y direction is widened. In this case, the viewfinder angle of view and the distance measurement range are the same in the y direction but are shifted in the x direction, so that the range monitored by the sensor array shifts in the x direction depending on the distance to the subject.

On the other hand, FIG. 1B shows the relationship between the photographing screen and the distance measurement area when the distance to the subject is L1. When the distance to the subject is L2, the range monitored by the sensor array shifts to the right side as shown in the figure and becomes unbalanced. Therefore, the right and left balance is adjusted without using the shaded portion on the right side of the figure. As a result, erroneous focusing on a subject existing around the screen is prevented.

As can be seen from FIGS. 1 (a) and 1 (b), objects other than the main subject, such as walls and desks, often exist around the screen. The hit rate can be improved. Also,
At a distance L1 shorter than the distance L2 to the subject, the monitor area in the viewfinder is further reduced, thereby increasing the distance measurement area outside the screen. Prevents deviation.

Next, referring to FIGS. 3 and 4, a description will be given of a distance measuring method based on the principle of triangulation employed by the camera of the present invention.

In the following embodiment, a sensor device of a distance measuring device in which pixels (sensors) each including a light receiving element are arranged in a line is referred to as a line sensor, and the pixels (sensors) are two-dimensionally arranged. For example, those arranged in a matrix are referred to as area sensors, and these are collectively referred to as a sensor array.

3 and 4, when the sensor arrays 2a and 2b detect the image of the subject 4 through the two light receiving lenses 3a and 3b spaced apart by the base line length B, the parallax is detected by the human eye. An image position difference x is produced by the same kind of effect as described above.

At this time, the subject distance L is obtained by the relationship L = B · f / x. Here, f is the focal length of the light receiving lens.

The outputs of these two sensor arrays 2a and 2b are processed via a D / A conversion circuit 10 by an arithmetic control unit (CPU).
1 receives the relative position difference x of the subject image, calculates the subject distance L according to the above formula, and controls the focusing unit 5 according to the subject distance L to focus on the subject. That is, a camera having an autofocus (AF) function is constructed by the above-described units.

As shown in FIG. 6C, even if the object 4 does not exist at the center of the screen 6 of the finder, but exists at a position shifted from the optical axis by an angle θ in the x direction. As shown in FIG. 4, the sensor position used as a reference in the sensor array 2a may be shifted by x0.

That is, the distance of a subject shifted by θ can be measured by the relationship θ = arctan (x0 / f).

As described above, by increasing the length of the line sensor, it is possible to extend the x-direction as a distance measuring position. After this process, the position where the sensor should mainly measure the distance may be determined by pattern detection.

For example, as shown in FIG. 6B, in a composition in which the object (person) 4 as a main subject does not exist at the center, focusing cannot be performed in the above-described embodiment. In view of the above, in the distance measuring device used in the camera according to the first embodiment, an area sensor is used instead of the line sensor.

As shown in FIG. 5 (b), the distance measurement range 2a 'by the line sensor was only a narrow range horizontally aligned with the photographing screen 12 of the camera.

On the other hand, the area sensor employed in the first embodiment has the same configuration as the two-dimensional arrangement of the line sensors.
The ranging area can be extended up to.

Therefore, when photographing with a composition as shown in FIG. 5A, in a conventional distance measuring apparatus, first, at the time of distance measurement, a main subject is put in the distance measurement range (the center of the screen), and the release button 101 is pressed. After half-pressing to measure the distance, re-holding the camera while holding the half-pressed state, moving the camera to the composition to be photographed, and further pressing the release button 101 to perform exposure, a so-called focus lock operation is a two-step exposure. I was going.

However, this operation is troublesome because the preliminary operation before photographing takes time, and a moving subject loses a shutter chance while a desired composition is obtained.
It lacked immediate shooting. On the other hand, if the range that can be measured is increased by using an area sensor as in the first embodiment, the main subject located at the edge of the shooting screen as shown in FIG. The distance can be measured.

However, even if such a technique capable of measuring the distance to the object at the edge of the screen is used, when the technique is implemented, it is possible to determine where the main subject is in the photographing screen by an increase in the number of measurable points. Detection technology is important.

When the number of distance measurement points increases extremely, it takes time to process these distance measurement points sequentially, and a longer time than focus lock is required. This is the opposite effect, and the disadvantage is greater because the area sensor is more expensive than the line sensor.

Hereinafter, referring to FIGS. 6 (a) to 6 (c),
The concept of a distance measuring device that detects the position of a main subject at high speed by AF using an area sensor will be described.

First, as shown in FIG. 6A, the camera emits light at a wide angle of view corresponding to the inside of the photographing screen before performing the distance measurement. At this time, the distribution of the reflected light on the area sensor in which the reflected signal light enters the area sensor according to the distance to the subject is equivalently shown in FIG. 6B.

As is apparent from this figure, the reflected signal light hardly returns from a complicated background because the distance is long. However, since the reflected signal light is returned from a person or a flower in the foreground because the distance is relatively short, the pattern on the area sensor is extremely simplified as shown in FIG. Become.

If the arithmetic control unit of the camera performs arithmetic control of the substantially binarized pattern signal according to a predetermined pattern determination sequence, it is possible to determine at which position in the photographing screen the main subject exists.

This concept is similar to that described with reference to FIG. 3 described above.
As shown in (c), if the distance measurement is performed by specifying the distance measurement point, the auto focus (AF) technology that can instantly focus on the position of the main subject regardless of where the main subject exists in the shooting screen is realized. it can.

As the distance measuring method at this time, whether the distance is measured by a so-called active method in which light for measuring is projected from the camera side or a passive method in which light for measuring is not projected is determined according to the situation at that time. You just need to switch.

Next, FIG. 7A shows an example of a configuration for performing distance measurement in a method of detecting the position of the subject 21 by pre-emission of the subject 21.

First, the light emitting control circuit 2 in the light emitting section 22
Auxiliary light is projected from the strobe 24 to the subject 21 under the control of 3, and the reflected signal light is transmitted to the two light receiving lenses 25a, 25a.
25b, and each of the two area sensors 26
a, 26b.

These area sensors 26a and 26b are
A subject image is received and photoelectrically converted, and their outputs are A /
A / D conversion is performed by the D conversion circuit 27, and the digital value of each pixel is input to the arithmetic control unit (CPU). The A / D conversion circuit 27 is controlled by an integration control circuit 27a.

Further, these area sensors 26a, 26
b, a steady light removing circuit 30 is connected, and under the control of the arithmetic and control unit 28, a DC light signal that constantly enters from the photographing screen is removed, and the pulse light (auxiliary light) from the strobe 24 is used. ) Can be obtained as an output signal. A method of measuring a distance using this function is referred to as an “active method”.

Therefore, when the reflected signal light is received on the area sensors 26a and 26b in a state where the stationary light removing circuit 30 is operated, the light receiving surface has a black light as shown in FIG. It will form an image consisting of parts. The analysis of the pattern of the image formed on such an area sensor is performed by a pattern determination unit (for example,
(Consisting of software), and if it is determined that the image pattern is a human figure, this can be considered as a main subject.

The camera according to the first embodiment of the present invention is based on the premise of the distance measuring apparatus having such a configuration, and further performs the focusing in consideration of the position error between the viewfinder and the distance measuring area by parallax. It is the characteristic point of.

That is, as a result of the pre-emission by the active method shown in FIG. 6A, a pattern is obtained as shown in FIG. 6B. In FIG. 7, 26a and 26b) calculate the distance by triangulation as described above with reference to FIG. 3 (pre-ranging). The actual distance measurement is performed using the closest distance of the distance data obtained at this time.

That is, as shown in the flowchart of FIG. 2A, after the pre-ranging is performed (step S1), the closest selection is performed (step S2), and the use area is set (FIG. a)) (step S3), the actual distance measurement is performed (step S4).

Further, as shown in the flowchart of FIG. 2B, it is not necessary to perform the distance measurement again. That is, image detection is performed by measuring the distance of a predetermined area (step S5), and among these, an image of only the substantially central area as shown by a circle in the example of the distance L1 in FIG. 1A is used. In accordance with the result of the distance measurement, an area to be used is determined again (step S6), the number of distance measurement points is further increased, and distance measurement data for focusing is selected from among them (step S6). Step S7).

At the time of setting the use area in step S6 of the flowchart of FIG. 2B, the distance measuring points are increased within a range where the shaded area of the area sensor of FIG. 1 is not used. Since the shaded area changes depending on the subject distance as described above, the closer the distance measurement result in step S5 is, the more the use area is limited. In particular,
At a long distance, 10 points in the x direction, 5 points in the y direction, and a point to be measured at a short distance, for example, at a distance L1, 7 points in the x direction
Distance measurement of five points is performed in the y direction.

Here, the difference between the sequence shown in FIG. 2A and the sequence shown in FIG. 2B is that the latter stores the image signals of all the sensor areas at the time of distance measurement in step S5, and that the image signals are stored. The point is that the distance measurement sequence in step S7 is performed using the data again. In addition,
When the user presses the release button 101 (see FIG. 1B) during camera shooting, shooting starts. However, a 1st release (1R) SW that is turned on in a half-pressed state is provided.
Cameras that determine timing prior to photographing based on the state of this switch are widely known.

The process of operating the distance measuring device prior to pressing the 1RSW and determining the use area prior to the operation of the 1RSW is shown in the flowchart of FIG. That is, in the same process, first, the distance is measured around the three circles shown in FIG. 1A (step S8),
The use area is set (step S1) according to the closest distance among the distance measurement results of these three points (step S9).
0) At the start of the photographing operation (step S11), predetermined settings are made so that distance measurement can be performed without using the previously hatched area in FIG. Then, the actual distance measurement is performed by pressing the 1RSW (step S
12).

According to such processing, since the use area is determined prior to photographing, FIGS. 2 (a) and 2 (b)
Can be measured faster than the processing of

If the above measures are not taken, FIG.
In the scene as shown in (a), even though the person 4 is located at the center, the sensor reacts to the vase 4a outside the finder 12 due to parallax, and the focus is adjusted to the position. It can happen. Then, as shown in FIG. 8B, the obtained photograph becomes out of focus.

As described earlier with reference to FIG. 5, a camera that can measure the distance anywhere on the screen and can focus is very convenient, but it is simple unless the device is modified as in the present invention. In the scene, the problem of side effects is even greater.

According to the present invention, the region 13a shown in FIG.
After the pre-range measurement near the center of the screen as described above, the distance measurement area is narrowed down as in the area 13a of FIG. 8C according to the result, and the distance measurement is performed again, so that the vase 4a is in focus. Accurate focusing can be performed without any side effects.

By the way, as in the scene shown in FIG. 8D, even if the vase 4a which is a rough subject is not outside the screen,
When it is desired to focus on the person 4, a technique for avoiding a situation where the vase 4a is in focus is required.

Therefore, as a second embodiment of the present invention, a camera that can correctly focus on such a scene will be described.

First, the basic concept of the second embodiment will be described with reference to FIG.

In FIG. 9A, reference numeral 23 denotes a finder, which is assumed to be viewed mainly by a person 4 located at a distance L2. However, due to parallax, the center of the distance measuring sensor 2a does not necessarily monitor the person, but rather monitors the vase 4a in front. In such a situation, the camera focuses on the vase 4a as the main subject because the vase 4a is at a short distance and at the center of the front.

However, although details will be described later, if parallax is sufficiently considered as in the second embodiment,
A scene located at the center of the screen and intended to be the main subject will not be a blurred photograph.

The present invention is applicable to a zoom lens which has recently been mounted on a compact camera.
That is, as shown in FIG. 9B, in a camera in which the size of the screen changes as indicated by reference numerals 12T and 12W in the figure by the user's operation, the entire area of the area sensor 13 is the distance measurement area. In the second embodiment, only the sensor in the area indicated as ΔθW is used at the time of widening, and ΔθT is used at the time of telephoto, in view of the possibility that focusing on a rough subject around the screen is likely to be performed. The distance measurement is performed using only the sensor in the region where the distance has been set.

Further, at the distances L2 and L1, FIG.
As shown in (d), it is considered that the distance measurement area 13 and the screen 12 are shifted.

In the second embodiment, as shown in FIG. 9A, for a subject at a distance L1, the portion of the sensor array 2a at an angle θ1 (point x1 from the optical axis) is viewed. Similarly, for the distance L2, a sensor (indicating the angle θ2) away from the optical axis by x2 looks at the center, and for the distance L3, a sensor (angle θ2) away from the optical axis by x3 θ3) looks at the front center.

Here, the relationship between θ and x is a relationship of tan θ = x / f using the focal length of the light receiving lens.

In consideration of the fact that the finder 23 has the zooming function 23a, if the distance is measured in a sequence as shown in FIG. 10, as shown in FIG. Accurate focusing is possible.

That is, step S20 is a step of detecting the zoom position, and step S21 is based on the result, and the monitor range on the sensor (ΔθT, ΔθW in FIG.
Reference). Thereafter, the subject images are detected by the sensor arrays 2a and 2b.
Distance detection is performed at the x1 portion of the sensor array that looks at the center of the distance of 1. As a result, Lx1 is set in step S24.
If approximately the same as L1, the distance L1 It can be seen that the subject is in the center of the screen.

Therefore, at this time, Lx1 is regarded as an important focusing distance candidate. In step S25, ΔL1 is subtracted to increase the priority, and in step S26, the screen center portion θ1 at this time is centered. Distance measurement is performed for a plurality of points within the range of Δθ determined in S21. However, after that, in step S35, the closest distance is selected from among them for focusing, so that the subtraction of ΔL1 and L1 are to be compared as short distances. Will be prioritized.

When step S35 is selected, the distance L1
Is compared by -ΔL1, but after the selection is made, it goes without saying that focusing is performed on the distance L1.

Steps S27, S28, S29, S30
Then, the above process is similarly repeated at the distance L2.

In this figure, since there is a person 4 in this figure, the distance Lx2 where Lx2 = L2 is measured in step S27, step S28 is branched to Y, and in step S29, Lx2-ΔL2 <L1 After the priority is improved in step S30, the distance is measured in a range of Δθ around θ2 in step S30.

At this time, the front vase 4a is also measured,
In step S29, since Lx2 is compared with the distance L1 of the vase 4a as a shorter distance than the actual one, step S35
, The distance of the person is selected, and the focusing is correctly performed on this distance. Steps S31 to S3
Reference numeral 4 denotes the same processing applied to the distance L3, and the distance measurement at the center of the screen with the distance L3 is prioritized.

In order to obtain the distance of the person 4, the image position θ
2, θL2 is detected and the distance B between the two lenses 3a, 3b is detected.
L = B / (tan θ L2 −tan θ 2) may be calculated using the following equation. If an image signal with sufficient contrast is not obtained as a result of the image detection performed in step S22, the integration control is switched at the time of distance measurement in steps S26, S30, and 34, and image detection is performed again to improve reliability. It is also possible to aim at higher precision by performing image signal detection with a certain level.

As described above, according to the second embodiment, in addition to the parallax of the first embodiment, the concept of giving priority to the image change due to zooming and the subject at the center of the screen is added. Therefore, the focus probability can be further improved.

In the second embodiment, the pre-ranging performed at the central three points in the first embodiment is performed at the center of the screen at each distance.

As shown in FIG. 11A, the distance measuring window 25 and the finder 23 of the camera are not arranged side by side.
In the case of disposition in an oblique direction, the above-described consideration of the error of the present invention may be applied not only to the x direction (horizontal) but also to the y direction.

The reference numerals 6W, 6S, 6T in FIG.
Each of them indicates a wide-angle, standard, and telephoto zoom angle of view, and reference numeral 2a indicates a monitor area of the area sensor. As described above, unlike the above-described embodiment, it is necessary to shift and limit the area to be measured not only in the x direction but also in the y direction.

Here, a method of the limitation will be described with reference to FIG.

The center of the distance measuring sensor 2a is
Assuming that the distance to view the same coordinate C as the center of L is L0, the angle of view of the viewfinder is one side θ, and the angle of view of the distance measuring sensor is one side φ,
When trying to measure the distance of the subject at the distance L1, it is better to use the portion indicated by the symbol A in the figure for distance measurement. This part protrudes from the screen due to parallax (see FIG. 1).
(Corresponding to the shaded portion of the distance L1 in (2)), so that even if focusing is performed at this portion, the subject is not captured in the screen.

Therefore, the range of the portion A is obtained by calculation. First, assuming that the distance between the finder optical axis and the distance measuring lens is S, and D in the figure is obtained, L0: S = (L0−L1): D, D = S × (L0−L1) / L0 = S − (SL1 / L0), and B = L1 tan θ−D = L1 tan θ−S + ｛(S · L
1) / L0｝. Therefore, since A = L1 tan θ−B, A = L1 tan φ−L1 tan θ + S− (SL1 / L0) ≒ S + L1 (tan φ−tan θ) = S−L1 (tan φ)
−tan θ). When this A is converted into an angle, arctan (A / L
1)

When the distance L1 is obtained, θ is obtained from the zoom position at that time, and since S and φ are already determined values, the portion not used for the distance measurement can be calculated by the CPU.

Such a relationship can be expressed not only in the x direction but also in the y direction.
CPU that controls the camera by applying to the direction
If the above-mentioned part A is excluded when the use area is determined in step S6 in the flow as shown in FIG.
As shown in (a), even with a distance measuring system in the x and y directions and a camera with a layout in which the viewfinder is displaced, it is possible to accurately measure only the object in the viewfinder screen.

Further, in addition to the viewfinder 23 and the distance measuring area 25, as shown in FIG. 13, the camera parallax includes the difference in the angle of view between the viewfinder and the photographing lens 7, the difference in the metering range between the viewfinder and the exposure, and the like. Must be considered.

In the second embodiment, the switching of the distance measurement area has been mainly described. However, the application of switching the range of the photometry unit 101 simultaneously with the switching of the distance measurement area is also possible based on the same concept. Further, the screen of the finder may be switched by a liquid crystal or the like according to the concept of pre-ranging according to the present invention (see FIG. 14).

[0091]

As described in detail above, according to the present invention,
It is possible to provide a camera having an autofocus function for accurately determining a main subject, accurately measuring a distance to the main subject, and further performing focusing, regardless of a zooming position and a subject distance.

[Brief description of the drawings]

FIG. 1A is a diagram illustrating a relationship between a photographing screen when a distance to a subject is L2 and a distance measurement area, and FIG. 1B is a diagram illustrating a photographing screen and a distance measurement when the distance to a subject is L2. FIG. 3C is a diagram illustrating a relationship with a region, FIG. 4C is an external configuration diagram of the camera according to the first embodiment, and FIG. 4D is a diagram illustrating a parallax S between a finder objective lens 50 and a distance measuring lens 51. FIG.

FIGS. 2A to 2C are flowcharts for explaining the operation of the camera according to the first embodiment.

FIG. 3 is a diagram for explaining a distance measuring method based on the principle of triangular distance measurement adopted by the camera of the present invention.

FIG. 4 is a diagram for explaining a distance measuring method based on the principle of triangular distance measurement adopted by the camera of the present invention.

FIG. 5A is a diagram illustrating an example of a shooting screen in which a range of a main subject located at an edge of a screen can be measured by increasing a range capable of measuring a distance using an area sensor;
(B) is a diagram showing that the distance measurement range 2a 'by the line sensor is a narrow range horizontally aligned at the center with respect to the photographing screen 12 of the camera.

FIGS. 6A to 6C are diagrams for explaining the concept of a distance measuring device that detects the position of a main subject at high speed by AF using an area sensor.

7A is a diagram illustrating a configuration example in which distance measurement is performed by a method of detecting a position of a subject 21 by pre-emission of the subject 21. FIG. 7B illustrates a state in which a stationary light removal circuit 30 is operated.
FIG. 4 is a diagram showing a state of a light receiving surface where reflected signal light is received on area sensors 26a and 26b.

FIGS. 8A to 8D are diagrams showing examples of various photographing screens.

FIGS. 9A to 9D are views for explaining a basic concept of a camera according to a second embodiment.

FIG. 10 is a flowchart for explaining a distance measuring operation of the camera according to the second embodiment.

FIGS. 11A and 11B are diagrams for describing an improved example of the camera according to the second embodiment.

FIG. 12 is a diagram for explaining a basic principle of an improved example of the camera according to the second embodiment.

FIG. 13 is a diagram for describing an improved example of the camera according to the second embodiment.

FIG. 14 is a diagram for describing an improved example of the camera according to the second embodiment.

[Explanation of symbols]

 Reference Signs List 1 arithmetic control unit 2 sensor array 3 light receiving lens 4 subject 5 focusing unit 6 viewfinder screen 7 photographing lens 8 strobe light emitting unit 9 strobe light emitting unit 10 D / A conversion circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Osamu Nonaka 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd. (72) Inventor Masataka Ide 2-43-2 Hatagaya, Shibuya-ku, Tokyo Olympus Optical Co., Ltd. F-term (reference) 2H011 AA01 BA05 BA14 CA01 2H051 BB07 BB09 BB20 CB22 DA02 DA03 DB01 EA29 EB13

Claims (4)

[Claims] 1. A finder means for observing a photographing screen, a distance measuring means arranged on an optical path different from the finder means and having a two-dimensional detection area in the photographing screen, A determining means for determining a two-dimensional detection limited area when the distance measuring means is operated at the second timing, according to a result obtained when the distance measuring means is operated at the first timing. 2. The method according to claim 1, wherein the distance measuring unit performs a distance measurement using an image signal of the object, and a signal from the object when the distance measuring light is projected irrespective of the image of the object. The distance measurement is performed by at least one of an active method that measures the distance according to the component. The distance measurement method at the first timing is different from the distance measurement method at the second timing. The camera according to claim 1, wherein: 3. A finder means for observing a photographing screen, a distance measuring means arranged on an optical path different from the finder means and having a detection area in a direction parallel to the photographing screen of the finder means; The distance measurement results in a plurality of predetermined areas are sequentially compared with predetermined values, and when it is determined that the comparison results are substantially equal, the distance measurement means performs a predetermined range centering on the area. Determining means for performing distance measurement and determining a focus position based on a comparison of the distance measurement results. 4. The camera according to claim 3, wherein the predetermined area is determined by a zooming position.