JP3374526B2 - Camera ranging device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus having a variable focal length.
Field of view linked to the focal length of the lens and the above shooting lens
Having a finder optical system with a changeable ratio
Finder optical system and auto camera
Passive triangulation with optical axis different from the focusing optics
The present invention relates to a distance measuring apparatus suitable for being applied to a distance method. 2. Description of the Related Art Conventionally, external light has been used as a distance measuring device for a camera.
One that uses passive triangulation is used.
ing. This type of distance measuring device uses an autofocus optical system.
The received subject image is received by a pair of line sensors.
Calculates the correlation between the pixel data obtained by each light
To obtain the distance measurement data,
This autofocus optical system is generally
It is provided on an optical axis different from the finder optical system. The observation section of the finder optical system includes a distance measuring area.
For example, a bracket-shaped ranging frame is used to visualize
Notation etc., the visual capacity of the ranging area for the subject
I am trying to make it easier. However, the viewfinder optical system is
The viewfinder magnification changes with the focal length of the academic system
While the autofocus optics
Is fixed. Therefore, the actual auto focus
Despite the fact that the distance measurement area where the optical system measures the distance does not change
The viewfinder magnification varies depending on the focal length.
Subject in the fixed frame shown
The size of the body image will be different. For example, shooting optics
Is the distance measurement frame and auto focus at the required focal length.
Make sure that the actual distance measurement area by the cas optical system matches
Although it is designed, the distance measurement area at the telephoto side
Is magnified with respect to the ranging frame, that is, from the observation window
Of the actual ranging area in the ranging frame
Part is settled, and conversely,
On the other hand, the ranging area is reduced with respect to the ranging frame.
In other words, when observing from the observation window, the actual
The subject around the distance measurement area will fit
As a result, if the subject is not
There is a possibility that inconvenience of performing erroneous distance measurement may occur. Therefore, conventionally, the focal length, that is,
The distance measurement is based on the distance measurement frame regardless of the
As is done, within the actual ranging area, the ranging frame
Executes the distance measurement operation using the pixel data corresponding to
Camera to obtain error-free ranging data
It has been proposed (JP-A-2-293833). SUMMARY OF THE INVENTION [0005]
The field of view for the ranging frame, especially on the telephoto side
Due to the narrowing of the range, it is impossible to measure the distance,
That the measured distance data is not reliable,
There is a problem that the possibility of being judged to be high increases.
In such a case, focusing cannot be performed.
As a way to deal with this, if you are at a similar distance
Preliminary distance measurement for other subjects that seem to be
Point the camera at the original subject while maintaining the distance
We adopt so-called focus lock function to perform shadow
Or at a predetermined focal position, for example, 5m.
A method of forcibly setting has been proposed. However
These methods understand the focus lock function
Difficult for photographers who do not have the required focus
In the position setting method, the probability of focusing is never high
I don't. The present invention has been made in view of the above circumstances.
Pixel data corresponding to the distance measurement frame in the distance measurement area
Distance measurement using the
The distance measurement calculation using the
A camera ranging device that can further reduce the probability of occurrence
It is intended to provide. SUMMARY OF THE INVENTION A camera according to the present invention has a measurement function.
The focusing device consists of a photographic lens with a variable focal length,
Field of view magnification can be changed according to the focal length of the lens
In a camera having a finder optical system,
Triangular distance measurement type with an optical axis different from that of the
Receives the subject image guided by the focusing optical system,
Pair of line sensors that capture pixel data
Used for distance measurement according to the focal length and the focal length
Storage means for storing the range of pixel data and a focal length
First, distance measurement data is obtained using pixel data in the same range.
Pixels outside the range used by the first distance measuring means
Second distance measurement means for obtaining distance measurement data using the data,
It is determined whether or not the distance measurement data by the first distance measurement means is valid.
Differentiating means, and distance measurement data by the first distance measuring means.
When the data is valid, the distance measurement data from the first distance measurement means
When the distance is invalid, the distance measurement data from the second distance measurement means is used.
Control means for adjusting the focal position of the photographing lens using the data
It is provided with. According to the present invention, the finder optical system is a photographing lens.
Field magnification is changed in conjunction with the focal length of the
The autofocus optical system is fixed. And detected
Match or pair with the ranging frame based on the focal length
The corresponding range is determined, and the pixel data within that range is used.
The distance measuring calculation is executed by the first distance measuring means, and similarly,
Using the pixel data in the other range as the second distance measuring means
The distance measurement calculation is executed. And with the first ranging means
The validity of the obtained ranging data is determined and if it is valid
The focus based on the distance measurement data obtained by the first distance measurement means.
Point position adjustment is performed. If the validity is denied
However, using the distance measurement data obtained by the second distance measurement means
The focus position adjustment is performed. Note that the second distance measurement
The means performs the distance measurement operation on condition that the validity is denied.
It may be performed. FIG. 1 shows a range finder according to the present invention.
FIG. 2 is a plan view illustrating an example of an optical system of the camera. Camera body
On the front side (upper side in the figure) of the camera 1 is a photographing lens constituting a photographing optical system.
Lens 2 is provided. This photographic lens 2 has a focal length
Is a zoom lens that can be changed continuously or multi-point
is there. Behind the optical axis of the taking lens 2, an aperture and a shutter (not shown)
The film 3 is arranged via a
You. The finder optical system F is connected to the photographing lens 2 and the camera.
It is interposed between the film 3 and 45 at the time of distance measurement with respect to the optical axis.
The optical axis is branched by the tilted (half) mirror 4 and
Of the camera body 1 through light deflecting means such as a prism inside.
Viewfinder display consisting of a translucent plate etc. at the imaging position on the rear surface
Has a configuration for observing the subject image via the unit 5
You. Suitable place of translucent plate for finder display unit 5, eg
For example, in the center position, a required large bracket-shaped ranging frame 50 is required.
Is marked. This distance measuring frame 50 is
For the subject image shown on the
It is for visually guiding the rear. This file
The optical system F is provided behind the taking lens 2.
Therefore, when the focal length of the taking lens 2 is changed,
The indian field magnification changes. In addition,
If the mirror 4 is of the total reflection type, retract from the optical axis during shooting
A known configuration that makes it possible is adopted. The finder optical system F is used as a photographic light source.
What is the position different from the academic system, that is, the optical axis of the taking lens 2
It has another different optical axis and the focal length of the taking lens 2
The power of gear transmission means and servo motors etc.
Finder field-of-view magnification can be changed via the air linking means
Even if such a configuration is adopted, the same finder function as above
Can be realized. An autofocus optical system AF is an embodiment of FIG.
In the example, provided in the lateral direction of the photographing lens 2, a pair of
Objective lenses 61, 62, mirrors 71, 72, 73 and one
A pair of line sensors 81 and 82 are provided. This auto
The focus optical system AF has at least a finder optical system F
Has an optical axis different from the optical axis. Pair of
The objective lenses 61 and 62 are located on the front of the camera body 1.
Disposed at a fixed distance away from each other and forward
Subject passed through those objective lenses 61 and 62
From the mirrors 71, 72 and 73.
So that they are guided to the corresponding line sensors 81 and 82, respectively.
It has become. The line sensors 81 and 82 are separated by a predetermined distance.
Are arranged in parallel with each other, and each
Light receiving elements are arranged in a line.
You. These line sensors 81 and 82 include an objective lens 61,
The image of the subject that has passed through 62 is received and a digital pixel
To the control unit 9 which converts the data into
It is being led. 10 is an operation of the control unit 9
Focuses the taking lens 2 on the basis of the obtained distance measurement data
It is a motor as driving means for driving to a position. FIG. 2 shows the control of a camera to which the present invention is applied.
It is a block diagram explaining a system. The control unit 9 has a CPU (medium
Central processing circuit) 91, ROM 92, RAM 93, etc.
And controls the overall operation of the camera in addition to the distance measurement calculation processing.
Things. The ROM 92 has a program for distance measurement calculation processing.
RAM, camera operation general program and specified
A table or the like relating to the distance measurement range is stored in advance. R
The AM 93 temporarily saves data in the middle of the arithmetic processing.
It is for. A switch S1 instructs distance measurement and exposure processing.
A shooting preparation switch and a switch S2 are used to instruct shooting.
With both switches, press both switches halfway to prepare for shooting
An operation is instructed, and a release instruction is issued in a fully pressed state
It is preferable to use a button type of a type. The motor 10 is driven from a lens control circuit 11.
The moving amount of the taking lens 2 is adjusted in response to the motion signal.
Therefore, the feeding amount is monitored by the encoder 12.
You. The encoder 12 is provided on the stationary side and the rotating side of the taking lens 2.
Bits, for example, coded position information, arranged face-to-face
The information of the mark member and each bit of this bit mark member
This is to read and detect the feeding amount.
The photographing lens 2 can be set to the in-focus position at distance
It has become so. The switch S3 is set to the telephoto side according to the operation direction.
A zoom that changes the focal length to the wide-angle side
Switch. 14 is a focal length control means, which is a switch.
The drive signal is supplied to the motor 13 in the operation direction of the switch S3 for the operation time.
To change the focal length. What
If the motor 13 uses a gear and a clutch, etc.
10 can also be used. The encoder 15
Facing the zoom lens in the zoom lens 2 on the stationary side,
Bit mark member and reading similar to the encoder 12
And code data according to the focal length.
Output. This taking lens 2 has a wide angle
There is a macro area on the outside that allows for close-up photography
Is used in the macro area.
Detectable by position data from encoder 15
ing. Switch S4 is for normal shooting and macro shooting
And a mode switch for instructing the switching. At 16, a photographing preparation switch S1 is turned on.
Brightness detection circuit that performs exposure detection when the
Therefore, the aperture value and shutter speed are set
Has become. FIGS. 3 and 4 show correlations in obtaining distance measurement data.
FIG. 5 is a diagram illustrating a method of calculation. FIG. 3 (a), FIG.
FIG. 3A shows a one-side shift system, and FIGS.
(B) shows a double-sided shift method. As shown in FIG. 4, in this example,
The objective lenses 61 and 62 of the focusing optical system AF are viewfinders.
Right side of the lens of the optical system F (the photographing lens 2 in this embodiment)
Are arranged in parallel. And as shown in FIGS.
The line sensor 81 on the side close to the photographing lens 2 is
And the line sensor 82 is used as a reference unit. The subject
For a distance of 3 m (FIG. 4, Do), the finder optical system F
AF frame AF and AF
Designed to match the center of the distance area
And In the case of a one-side shift, for convenience of explanation, the reference portion
Is composed of light receiving elements A1 to A4.
And the line sensor 82 of the reference unit is the light receiving element B1 to B8.
On the other hand, in the case of a two-sided shift,
For convenience of description, the line sensor 81 of the reference unit is a light receiving element A
1 to A6, and the reference line sensor 82
It is assumed that the optical elements B1 to B6 are constituted by the same number.
You. First, the case of one-side shift will be described.
The selection of the light receiving element of the in-sensor 81 is fixed,
On the other hand, the line sensor 82 is used for correlation calculation.
The light receiving elements that output pixel data are sequentially shifted and selected
Is done. That is, the pixel data of the light receiving elements A1 to A4
On the other hand, first, the pixel data of the light receiving elements B1 to B4 is selected.
Then, a correlation operation is executed (shift S in FIG. 4A). ₀ To
Corresponding), and sequentially to the pixel data of the light receiving elements A1 to A4.
On the other hand, the pixel data of the light receiving elements B2 to B5 is (FIG. 4A)
Shift S ₁ ), The pixel data of the light receiving elements A1 to A4.
The pixel data of the light receiving elements B3 to B6 is
(A) Shift S _Two ), The image of the light receiving elements A1 to A4
The pixel data of the light receiving elements B4 to B7 is
(Shift S in FIG. 4A) _Three And finally,
The light receiving elements B5 to B5 correspond to the pixel data of the optical elements A1 to A4.
The pixel data of B8 is (shift S in FIG. _N Equivalent to)
The selected correlation calculation is performed. And
Condition that the result of each correlation operation exceeds a predetermined threshold
The data with the highest correlation value is used as the distance measurement data
The known method is adopted. The predetermined threshold is measured
Set to determine if the results are reliable.
Below this threshold, ranging data cannot be obtained.
Treated as missing. Next, the case of a two-sided shift will be described.
The light receiving elements of the in sensors 81 and 82 are sequentially shifted together.
Selected. That is, first, the light receiving elements A3 to A6
The pixel data and the pixel data of the light receiving elements B1 to B4 are
4 (b) shift S ₀ ') And the correlation operation is selected
Executed, and further sequentially, pixel data of the light receiving elements A3 to A6.
And the pixel data of the light receiving elements B2 to B5 (FIG. 4B)
Shift S ₁ '), The pixel data of the light receiving elements A2 to A5.
The pixel data of the light receiving elements B2 to B5 with respect to the
(B) shift S _Two '), The light receiving elements A2 to A5
The pixel data of the light receiving elements B3 to B6 are compared with the pixel data.
Is (shift S in FIG. 4B). _Three ') And the last
And light receiving elements for the pixel data of the light receiving elements A1 to A4.
The pixel data of B3 to B6 correspond to the shift of FIG.
S _N ') And the correlation operation is executed for each
It is. Then, as a result of each correlation operation, it is assumed that the correlation value is the highest.
Is used as distance measurement data. Here, in FIG.
In this case, the axis connecting the subject and the center of the distance measurement area is the distance Do
Center axis of distance measuring frame and principal point A1 of objective lens 61
And a line segment DoA1 connecting. Therefore, it is more than point Do.
Distance D which is the minute proximity position _N Frame and ranging area in
The shift (parallax) between the center and P is Px. On the other hand, in the case of a two-sided shift, the object and the distance measurement
The axis connecting the rear center is the distance measurement frame at the distance Do.
The center axis and the principal points A1 'and A2' of the objective lenses 61 and 62
A line segment DoAc connecting the middle point Ac is obtained. Therefore, proximity
Distance D _N Is Px '. [0027] Then, in the nearer distance region than the distance Do,
Therefore, since Px <Px ′, the correlation calculation is
The same number of times, one-side shift is more parallax
That small and accurate ranging data can be obtained
Become. FIGS. 5 to 8 show distance measuring frames according to the photographing distance.
Ranging operation considering parallax between the camera and ranging area
It is to explain. Fig. 5 shows the distance measurement according to the shooting distance
Parallax relationship between frame 50 and ranging area 80
(A), when the shooting distance is infinite, (b)
Is the case where the shooting distance is 3m, and (c) is the case where the shooting distance is 1m.
In this case, (d) shows the case where the shooting distance is 0.5 m. As shown in FIG. 1, an autofocus optical system
The optical axis of AF is separated from the optical axis of finder optical system F,
In the example of FIG. 1, the optical axis of the finder optical system F is
Optical axis of autofocus optical system AF is set to the right side of
And the line sensor is located closer to the optical axis of the finder optical system F.
A line sensor 82 is provided on the right side of the
You. Here, FIGS. 5A to 5D will be described.
You. Now, the subject is located 3 m in front of the camera body 1.
The luminous flux from this subject and its surroundings is
Consider the case where the light is passed over the line sensor 81 after passing through
You. Then, of the luminous flux from the subject, the line sensor 81
When the range where light is received by the distance measuring area 80 is
The distance measurement area 80 and the distance measurement frame 50 match at a distance of 3 m.
It is assumed that it has been designed in advance. That is, the figure
When the subject is at a distance of 3 m as shown in FIG.
The photographer shoots the subject shown in the finder display section 5.
The distance measurement frame 50, which is the position intended for distance measurement, and the camera
The distance measurement area 80 where the actual distance measurement is performed coincides.
You. By the way, as shown in FIG.
The luminous flux passing through the objective lens 61 from the subject is
Incident on the optical axis of the objective lens 61 from a more parallel angle
Therefore, this long-distance subject image is
Changes to the left side, that is, the side closer to the finder optical system F.
Will be ranked. On the other hand, as shown in FIG.
The light beam passing through the objective lens 61 from the body is
Incident on the optical axis of the
Therefore, the subject image at this distance is
Side, that is, the side away from the finder optical system F.
The Rukoto. Further, as shown in FIG.
Of light passing through the objective lens 61 from the subject at a close distance
Is an angle further deviated from the optical axis of the objective lens 61.
The subject image at this close distance is line
Displaced further to the right on the sensor 81,
Approximately half will come off. FIG. 6 shows the structure of the line sensor and the distance measurement range.
FIG. Note that the license applied to the present invention is
The structure of the sensor 81, 82 is the one-side shift shown in FIGS.
It can be applied to both
In the case of the one-side shift method, the light receiving element of the line sensor 82
Is the number of light receiving elements of the line sensor 81, for example,
Double-sided, both lines
The number of light receiving elements of the sensor 81, 82 is set to be the same.
You. For convenience of explanation, the line sensor shown in FIG.
This will be described as a sensor 81. A to G are line sensors 8
1 shows points obtained by equally dividing 6 in the length direction, and AF1-A
F6 indicates a distance measurement range used when obtaining distance measurement data.
are doing. The G side is a side close to the finder optical system F.
is there. AF1 uses light receiving elements in the range of A to C,
F2 uses a light receiving element in the range of B to D, and AF3 uses C
To E, and the AF4 is in a range of D to F.
AF5 is a light receiving element in the range of E to G.
The AF6 has a range of A to G, that is,
An optical element is used. Closest shooting distance less than 0.5m
In the distance, the distance measurement range AF4, A
It can be seen that F5 is off. The control unit 9 determines the distance measurement ranges AF1 to AF
Distance measurement data is required for each of the 6
You. In FIG. 6, the shooting distance is in a range from 1 m to infinity.
The surrounding area is set to the normal shooting mode.
Macro mode, normal shooting mode and macro mode
The mode can be switched by one taking lens 2
The control unit 9 is based on the detection data from the encoder 15
Or from the state of the mode switch S4,
The mode is identified. Ma
When the control unit 9 is set to the macro mode,
AF1 to AF3 are set within the AF frame
The distance measurement ranges AF4, AF5 and
AF6 is set. This ranging frame
The correspondence between the inside and outside and each ranging range is stored in the ROM 92.
Have been. It should be noted that whether the area is a macro area is determined by the shooting level.
Depending on the type of the encoder, an encoder may be used instead of the encoder 15.
It is also possible to identify with the reader 12. Next, measurement is performed using the flowchart of FIG.
The calculation operation of the distance data will be described. Switch S1
When turned on, the distance measurement process is started and the objective lenses 61 and 6 are turned on.
The luminous flux of the subject passing through the line sensors 81 and 82
The light is received by all light receiving elements, converted to digital values, and
9 (# 2). Pixel data from all light receiving elements taken in
Line range for each of the distance measurement ranges AF1 to AF6 based on the
Between the sensor 81 and the line sensor 82,
Each distance measurement data is calculated (# 4). Where the shooting lens
Is set to macro mode.
(# 6), if not macro mode, normal mode
Therefore, the normal distance measurement processing “normal photographing” (# 8) is executed.
Then, this flow ends. On the other hand,
If the distance measurement data was obtained in the distance measurement ranges AF1 to AF5,
It is determined whether it is (# 10). AF area AF1-AF
If the distance measurement data has been obtained in step 5,
Within the frame, that is, within the range AF1-AF3.
It is determined whether or not data has been obtained (# 12). Measurement
If the distance measurement data is obtained in the distance ranges AF1 to AF3,
Whether the distance measurement data is less than a predetermined value, for example, 1 m
Is determined (# 14).
Is selected as the distance measurement data (# 16),
End the row. In the case of NO at # 12 and # 14,
Measurement is performed outside the distance measurement frame, that is, in the distance measurement ranges AF4 and AF5.
It is determined whether or not distance data has been obtained (# 1).
8). Distance measurement data is obtained in the distance measurement ranges AF4 and AF5.
If the distance measurement data is less than a predetermined value, for example, 1 m or less.
Is determined (# 20).
If the most recent value is selected as the distance measurement data (# 2
2), end this flow. Also, N in # 18 and # 20
If it is O, a specific value, for example, 0.6 m
This is set (# 24), and this flow ends. On the other hand, in # 10, the distance measurement ranges AF1 to AF5
If no distance measurement data was obtained in
It is determined in Step 6 whether or not the distance measurement data has been obtained (# 2).
6), no distance measurement data is obtained even in the distance measurement range AF6
At this time, the routine proceeds to # 24, where a predetermined value of 0.6 m is set.
On the other hand, since the distance measurement data has been obtained in the distance measurement range AF6,
If there is, whether the distance measurement data is less than the specified value 1m
Is determined (# 28).
The distance data is adopted (# 30), and this flow ends.
You. FIG. 8 shows a subroutine of "normal processing" of # 8.
FIG. In normal processing, first,
Whether or not ranging data was obtained in the ranging ranges AF1 to AF5
Is determined (# 40), and distance measurement data is obtained.
If the most recent value is selected as the distance measurement data (# 4)
2) Return. On the other hand, no ranging data is available.
If it is, whether the distance measurement data is obtained in the distance measurement range AF6
It is determined whether or not the distance measurement data has been obtained (# 44).
Then, the distance measurement data of the distance measurement range AF6 is adopted (#
46) Conversely, if no distance measurement data has been obtained,
A specific value, for example, 0.6 m is set as impossible (# 4
8) Return. As described above, according to the detected focus position,
To obtain ranging data within the ranging range in the ranging frame.
Adjust the focus position using the distance measurement data, and
If the data is not valid, the range
Distance measurement is not possible because the distance measurement data is adopted
Is further reduced. FIGS. 9 to 11 show the distance measuring frame 50.
Of the ranging area 80 according to the focal length of the photographing lens 2
9 illustrates a distance measuring operation in consideration of scaling. FIG. 9 shows the focal length for the distance measuring frame 50.
FIG. 9 is a diagram showing the relationship of scaling of a distance measurement area 80 according to separation.
(A) is the focal length f = 35 mm, (b) is the focal length
When the distance f is 70 mm, (c) shows the focal length f = 105 m
m. With respect to the distance measuring frame 50, the distance measuring area 80
The reason why changes in scale is as follows. finder
The optical system F is a focal length f of the photographing lens 2, that is, an image magnification.
The viewfinder magnification changes depending on the
The magnification of the focusing optical system AF is fixed. This place
In this case, the distance measurement area 80 is independent of the viewfinder magnification.
It is fixed and only measures the specific position of the subject.
The distance will be executed. On the other hand, the viewfinder display 5
The subject is enlarged or reduced according to the viewfinder magnification.
Of the subject that fits within the frame of the ranging frame 50
The range will differ depending on the viewfinder magnification. FIG. 9A shows the distance measuring frame 5.
0 and the size of the distance measurement area 80 match.
In the state, the actual distance measurement data of the camera within the distance measurement frame 50 is displayed.
Data, so it matches the distance measurement position intended by the photographer
I do. However, as shown in FIG.
Viewfinder display as viewfinder magnification increases
The subject shown in the section 5 (and the ranging area 80) is also enlarged and measured.
Only part of the subject can fit within the distance frame 50
Is shifted from the ranging area 80 where the ranging is actually performed.
Comes out. FIG. 10 shows the structure of the line sensor and the distance measurement range.
FIG. Note that the laser applied to the present invention is
The structure of the in-sensors 81 and 82 is one-sided as shown in FIGS.
It can be applied to both
In the one-side shift system, the light
The number of elements is an example of the number of light receiving elements of the line sensor 81.
For example, it is twice as many.
The number of light receiving elements of the line sensors 81 and 82 is set to be the same.
ing. For convenience of explanation, the line sensor of FIG.
This will be described as an in-sensor 81. A to G are line sensors
81 is a point obtained by dividing the length into eight equal parts in the length direction.
AF6 sets a distance measurement range used when obtaining distance measurement data.
Is shown. The G side is a side close to the finder optical system F.
It is. AF1 uses light receiving elements in the range of A to C,
AF2 uses light receiving elements in the range of B to D, and AF3 uses
Light receiving elements in the range of C to E are used, and AF4 is
A light receiving element in the range of EG is used.
An optical element is used, and AF6 has a range of A to G,
A light receiving element is used. The focal length of the taking lens 2 is 10
At 5 mm, the distance measurement ranges AF1 and AF5 are
You can see that it is out of the range. Then, the control unit 9 determines the distance measurement ranges AF1 to AF
Distance measurement data is required for each of the 6
You. In FIG. 10, the focal length of the photographing lens 2 is
It can be changed at least in the range of 35 mm to 105 mm.
The control unit 9 detects the detection data from the encoder 15.
Based on the data stored in the ROM 92 in advance.
Using Table 1, any focal length range
And corresponding to the corresponding focal length range
Set the measured range as inside or outside the frame
It has become. [Table 1] That is, the focal length f is 35 mm to 55 m
In the range of m, as shown in FIG.
Since the areas substantially coincide with each other, all the distance measurement ranges AF1 to AF5
Is set to be within the distance measurement frame. Focal length f is 56
In the range of mm to 85 mm, as shown in FIG.
A part of the surrounding AF1 and AF5 is partially
The distance measurement ranges AF2 to AF4 are
And the distance measurement ranges AF1 and AF5 are within the distance measurement frame.
It is set to outside. Further, the focal length f is 86 mm to 1
In the range of 05 mm, as shown in FIG.
Part of AF2 and AF4 also partially extend from the distance measurement frame 50
The AF area AF3 is within the AF frame.
The distance measurement ranges AF1, AF2, AF4, and AF5 are
It is set outside the frame. Next, using the flowchart of FIG.
The calculation operation of the distance measurement data will be described. Switch S1
Is turned on, the distance measurement process is started and the objective lens 61,
The luminous flux of the subject that has passed through the line sensors 81 and 82
Is received by all light receiving elements and converted to digital values for control.
It is taken into the unit 9 (# 60). Pixel data from all light receiving elements taken in
Line range for each of the distance measurement ranges AF1 to AF6 based on the
Between the sensor 81 and the line sensor 82,
Each distance measurement data is calculated (# 62). Here,
Is read from the encoder 15 (#
64) Then, based on Table 1, measurement corresponding to the focal length was performed.
Distance measurement data is obtained within the distance range, that is, within the distance measurement frame.
Is determined (# 66), and distance measurement data is obtained.
If so, use the most recent value as the distance measurement data
Select (# 68) and end this flow. On the other hand, when the distance measurement data is obtained in the distance measurement frame,
If not, then it is outside the ranging frame, that is,
It is determined whether or not ranging data was obtained in a ranging range other than
Separated (# 70), even if ranging data has been obtained
If the most recent value is selected as the distance measurement data (# 7)
2), end this flow. Further, distance measurement data can be obtained even outside the distance measurement frame.
If no distance measurement data has been obtained in the distance measurement range AF6,
It is determined whether or not it has been obtained (# 74).
If so, the value is adopted as distance measurement data (# 76). Profit
If not, a specific value, for example, 10
m is set (# 78), and the routine returns. As described above, according to the detected focal length,
To obtain ranging data within the ranging range in the ranging frame.
Adjust the focus position using the distance measurement data, and
If the data is not valid, the
Distance measurement data is adopted.
The rawness will be further reduced. According to the present invention, pixels in a range corresponding to the focal length are
Use the data to determine ranging data and determine its effectiveness.
If it is valid, use the distance measurement data and
If not, the distance measurement calculated using pixel data outside the above range
Adjusting the focal position of the taking lens using data
Auto focus with a pair of line sensors
The optical axis of the scanning optical system has a different optical axis from that of the finder optical system.
Finder field of view magnification
Regardless of the range, the probability of occurrence of distance measurement failure
It can be further reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing an example of an optical system of a camera to which a distance measuring device according to the present invention is applied. FIG. 2 is a block diagram illustrating a control system of a camera to which the present invention is applied. 3A and 3B are diagrams for explaining a method of correlation calculation when obtaining distance measurement data. FIG. 3A shows a one-side shift method, and FIG.
Indicates a two-sided shift method. 4A and 4B are diagrams for explaining a correlation calculation method when obtaining distance measurement data. FIG. 4A shows a one-side shift method, and FIG.
Indicates a two-sided shift method. 5A and 5B are diagrams illustrating a parallax relationship between a ranging frame and a ranging area according to a shooting distance, wherein FIG. 5A illustrates a case where the shooting distance is infinite, FIG. 5B illustrates a case where the shooting distance is 3 m, (C)
Indicates that the shooting distance is 1 m, and (d) indicates that the shooting distance is 0.5 m.
Is the case. FIG. 6 is a diagram showing a relationship between the structure of a line sensor and a distance measurement range. FIG. 7 is a flowchart illustrating an operation of calculating distance measurement data. FIG. 8 is a flowchart showing a subroutine of “normal processing”. FIGS. 9A and 9B are diagrams showing a scaling relationship between a distance measurement frame and a distance measurement area according to a focal length, wherein FIG.
In the case of 35 mm, (b) shows the case where the focal length f = 70 mm, and (c) shows the case where the focal length f = 105 mm. FIG. 10 is a diagram showing a relationship between the structure of a line sensor and a distance measurement range. FIG. 11 is a flowchart illustrating an operation of calculating distance measurement data. [Description of Signs] 1 Camera body 2 Photographing lens 3 Film 4 Mirror 5 Viewfinder display section 50 Distance measuring frames 61, 62 Objective lenses 71, 72, 73 Mirror 80 Distance measuring areas 81, 82 Line sensor F Viewfinder optical system AF Auto focus Optical system 9 Control unit 91 CPU 92 ROM 10, 13 Motor 11 Lens control circuit 12, 15 Encoder 14 Focal length control circuit S1 Shooting preparation switch S2 Release switch S3 Zoom switch S4 Mode switch AF1 to AF6 Distance measurement ranges A1 to A6, B1 ~ B8 Light receiving element

Continuation of front page (56) References JP-A-3-141311 (JP, A) JP-A-63-171314 (JP, A) JP-A-63-172207 (JP, A) JP-A-63-17418 (JP) JP-A-2-293833 (JP, A) JP-A-7-325248 (JP, A) JP-A-7-140376 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB G02B 7/28-7/34

Claims (1)

(57) [Claim 1] In a camera having a photographing lens with a variable focal length and a finder optical system whose field magnification can be changed in conjunction with the focal length of the photographing lens, A pair of line sensors that receive a subject image guided from a triangulation-based autofocus optical system having an optical axis different from that of the finder optical system and capture the pixel data thereof, respectively, according to the focal length and the focal length Storage means for storing a range of pixel data used for distance measurement, first distance measurement means for obtaining distance measurement data using pixel data in a range corresponding to the focal length, and first distance measurement means. a second distance measuring means for obtaining a distance measurement data by using the pixel data outside the range used, the discriminating means the distance measurement data according to the first distance measuring means to determine valid or not, measuring the first Distance measurement
When the data is valid, the distance measurement data from the first
And a control means for adjusting the focal position of the taking lens by using distance measurement data from the second distance measurement means when the distance is invalid .