JP3431200B2 - camera - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION 1. Field of the Invention
Measures subject distance according to the reflected signal light from the object
Camera with ranging deviceAbout. [0002] 2. Description of the Related Art Generally, in a distance measuring device using infrared light,
For distance measurement between a subject and a glass plate, for example,
When there is an object that specularly reflects the light
Cannot measure distance accurately. In other words, the subject through the glass
He was said to be unable to focus on his body. that is,
In addition to reflected light from the subject, reflected light from the glass surface
The scene outside the car window, because it is incident on the device
It is difficult to shoot items in the shop window
It was difficult. In order to solve this problem, for example, Japanese Patent Application Laid-Open No. Sho 62-3
As described in Japanese Patent No. 2427, from this glass etc.
In order to make it difficult to receive the reflected component of
A road limiting member was provided. Japanese Patent Application Laid-Open No. Sho 62-49311 discloses that
Using a two-segment element, multiple light-receiving elements
Divided by the number of
Of them, control so that some or all can be taken out,
Compare this value with the output of the infinite light receiving element to adjust the focus.
Going distance measuring devices have been proposed. [0005] However, the above-mentioned Japanese Patent Application Laid-Open
The proposal described in JP-A-62-32427 is simply
The reflection component has become difficult to receive due to the optical path limiting member
Detects the shooting of the intervening glass (through glass)
Rather than taking measures, it only suppressed the extent of erroneous ranging
In other words, shooting through glass is not completely possible. Further, Japanese Patent Application Laid-Open No. Sho 62-49311 describes
The proposed proposal also covers a glass that is closer to the shooting lens.
Can only deal with Further, distance measurement is performed based on the luminance distribution of the subject.
In the passive mode, shooting through glass is possible, but light projection
Very high cost compared to active shooting
Was. The present invention has been made in view of the above points, and
Focus on landscapes and exhibits in shop windows
An inexpensive AF that can be combined is provided. Accordingly, the present invention provides a method for measuring a subject distance.
Eliminates erroneous distance measurement due to reflected light from glass etc.
InexpensiveCamera with ranging deviceIntended to provide
I do. [0010] The present invention achieves the above object.
To achieveLight is projected on the subject and reflected from the subject
A camera with a distance measuring device that focuses by receiving light
Distance measuring light projecting means for projecting light for distance measurement,
The subject reflected light by the projected light from the distance measuring
A light-receiving means for distance measurement, which is different from the projection light for distance measurement.
Light detecting means for detecting through glass,
It is arranged at a position different from the distance light receiving means,
In the glass of light emitted by the light emitting means for detecting through glass
The glass anti-reflection plate is placed at a position to receive the reflected light
When the light receiving unit and the shooting mode through glass are selected
At the time of detection by the glass reflected light receiving means
Compares the light intensity between the light intensity and a predetermined reference light intensity
The comparison means, and the comparison means
If the output light is larger than the reference light, the camera
Be in a position where distance measurement is not affected by reflected light.
Provide a camera composed of display means for notifying
You. [0011] [0012] BRIEF DESCRIPTION OF THE DRAWINGS FIG.
Will be described. First, referring to FIG. 1, a distance measuring apparatus according to the present invention will be described.
The concept of the principle of detection through glass will be described. In this distance measuring device, the light emitting element (IRE)
D) 1 is directed to the subject 7 via the light projecting lens 2
Projects ranging light. Reflection reflected from the subject 7
Light is guided by the light receiving lens 3 to the light position detecting element (PSD) 4
Receive light. The light projecting lens 2 and the light receiving lens 3 are
It is assumed that they are arranged at a distance S (base line length). This
And the subject distance L₇Changes, the
Angle φ incident on optical lens 3₇Changes, so the PSD
4 signal light position x₇Changes. PSD 4
Lighting position x₇And total signal light quantity i_pφCurrent depending on
Signal i₁, I_TwoIs output to the AFIC 5 as a signal. The AFIC 5 receives the current signal i₁, I
_TwoFrom the signal light position x₇Is a circuit for detecting subject
Distance L₇Is this x₇And baseline length S and light receiving lenses 3 and P
Distance f between SD4_JFrom (Equation 1) Is required in the relationship. However, as shown in FIG.
If there is a glass 6 in front, as shown by the dotted line in the figure, the lens
A part of the ranging light projected from the lens 2 is specularly reflected on the glass 6.
Incident on PSD4. The incident position x of the regular reflection light₆Is tentatively
6 is perpendicular to the optical axis of the light emitting / receiving lens,₆Only separated
If they are arranged at₀Is tan θ₀= 2 · L₆/S...(2) Becomes Therefore, PSD4 (Equation 2)At the same time, specular reflected light is incident on the AFIC5
Is the correct distance measurement light incidence where the reflected light from the subject is incident
Position x₇Can not ask. When the glass 6 is tilted by the angle φ,
Is θ₀Should be added to φ. However, in FIG. 1A, the light indicated by the dotted line
The line is only light scattered by the projection lens 2 and is projected for distance measurement.
It is different from the main beam that is illuminated. Therefore, as shown in FIG.
x_IJust scan and tan θ₀= F_T/ X_I              (F_T: Flood light
Focal length) The main beam for distance measurement
Intense photocurrent i due to direct irradiation on PSD4_pφIs P
Output from SD4. Generally, the reflected signal light for distance measurement is applied to the subject 7.
Of the scattered light, the light that enters the light receiving lens
In the main beam output from the projection lens 2,
It is only on the order of tens of thousands. However, as shown in FIG.
The light that has been specularly reflected from the glass and incident on the PSD
3% to 4% according to the reflectance of
Light more than three orders of magnitude larger than in case
And Thus, when IRED1 is shaken,
At the position where the glass is located, as shown in FIG.
4 is θ₀ Sharp rising characteristics at the place
Is shown. Also, there is no glassIfShown in FIG. 1 (d)
As shown in FIG. FIG. 2 shows a first embodiment according to the present invention.
The configuration and description of the distance measuring device mounted on the camera
You. In this distance measuring device, the light projecting system
Generates distance measuring light (infrared light) to be projected by driving the cover 10
And the ranging light from the IRED1 to the subject.
Move the light projecting lens 2 and the IRED 1
And a scanning unit 11 for detecting the light receiving system
Light-receiving lens 3 for condensing the reflected light from
A PSD 4 for receiving the reflected light and photoelectrically converting the reflected light;
Calculates the incident position of the reflected signal light using the output from
Using the distance measuring unit 8 and the sum of the PSD outputs, the reflected signal amount detection is performed.
And a light amount detection unit 9 for emitting light. The CPU 12 drives each component.
When controlling and causing the IRED to emit light via the driver 10
Both were obtained from the signal of PSD4 via the distance measuring unit 8.
Calculates the subject distance from the incident position of the reflected signal light,
From the output of the quantity detector 9 and the scan position of the IRED,
Or perform peak detection. Further, the CPU 12 displays a diagram based on the calculation result.
Focusing unit 15 that focuses on a non-photographing lens
A display unit 13 provided in the camera finder;
Light emission / stop of the trobo unit 14 is also controlled. Switch 1 provided in CPU 12
6 and 17 are O when the photographer operates the shutter button.
With the N switch, press the shutter button halfway
Switch 16 is called the 1st release switch.
When the CPU 12 closes this switch,
Perform the distance measurement operation. Also, press the shutter button
Causes switch 17 to close, which is 2nd
The CPU 12 is called a release switch.
Take a picture with the ring. FIG. 3 shows a scan of the IRED 1 shown in FIG.
About the sensor unit 11, the distance measuring unit 8, and the light amount detecting unit 9,
The configuration is described below. In FIG. 3, motor drivers 28 to I
When the drive current is sent to the RED scan motor 20,
The motor 20 rotates the feed screw 24 so that the movable part 22
It moves in the x direction along the guide 23. The IRED 1 is fixed to the movable part 22.
And the CPU 12 is attached to the motor 20.
A gear 21 and a black-and-white putter rotated by the gear 21
Rotation detecting gear 25 with a photoreflector
The movement amount is monitored by a rotation detection unit. The movable part 22 is pressed against a switch 27.
When the switch is closed, the switch 27 is closed,
Be placed. Therefore, from the closed position of the switch 27, the
When the motor 20 rotates a predetermined amount, as shown in FIG.
The IRED 1 moves on the optical axis of the light projecting lens 2. The SPD 4 has two outputs
Pumps 30 and 31 respectively. These current signals
No. i₁, I_TwoIs low input impedance,
The signals are input to the amplification transistors 32 and 33 and amplified.
However, this amplified signal flows through the resistor 47 and is converted into a voltage signal.
Is replaced. This corresponds to the current signal i₁ + I_Two Light proportional to
It becomes a quantity signal. Also, a current equal to the amplification current
Current mirror consisting of the transistors 34, 35 and 37, 38
Flow through the two compression diodes 36 and 39 by the circuit.
I will. The output voltage of these diodes is
0, 41, the pair of NPN transistors 42, 43
Entered in the base. These transistors are
Connected to a current source through which the current I flows.
Have been. This flows through the NPN transistors 42 and 43
Current to I_A , I_B Then I_A + I_B = I (4) Also, (Equation 3) Becomes Where β is the R of transistors 32 and 33_fe, V
_T Is thermal voltage, I_S Are diodes 36, 3
9, the reverse saturation current of the transistors 42 and 43.
  Therefore, from (5),       i₁ / I_Two = I_A / I_B                       … (6) Furthermore, taking into account equation (4), (Equation 4) Therefore, this I_A Is charged to the capacitor 45
Since I is a constant, the voltage generated at both ends of the capacitor
From the pressure, i₁ / (I₁ + I_Two ) Can detect
You. As shown in FIG. 3B, the IRED 1 is a light projecting lens.
2 and on the optical axis of the light receiving lens 3
When aligning the ends and keeping these optical axes parallel, the reflected signal
Light incident position x₇ Is the subject distanceL ₇ And the baselineLength S,
Light receiving side focal length f_J Than, x₇ = S ・ f_J / L₇                     … (8) Is established. According to the characteristics of PSD4, the length of PSD
Let t be i₁= X₇・ (I₁+ I_Two) / T… (9) Take a relationship. Therefore, from equations (8) and (9), (Equation 5) Substituting equation (7), (Equation 6) Becomes the distanceL ₇ Is the known number t, S, f_J ,
I and I detected_A More required. CPU 12
The lens 15a for lens alignment
And this 1 /L ₇ Adjust according to. Referring to the flowchart shown in FIG.
The operation of the distance measuring device configured as described above will be described. First, the first release switch is input.
Is determined (step S1).
(YES), the motor speed N and the target n are reset.
(Step S2). In this state, IRED1 returns to the initial position.
There is. Next, when the motor 20 rotates forward, n is input.
Increment (step S4) and count the number of revolutions N
(Step S5). Then, compare the target n with the rotation speed N
(Step S6) If n and N are equal (YES),
The light amount is detected (step S7), and if n ≠ N (N
O), and return to step S5. Therefore, N is 1 count,
Each time the count is increased, the light amount is detected. This
Is detected by causing the IRED 1 to emit light,
The voltage generated at the resistor 47 in FIG.
This is done by reading out with an A / D converter. Next, when the rotation speed N is N_CTo determine if
(Step S8), N = N_CWhen (YES), measure the distance
Perform (Step S10). Where N_CIs IRED1
Is the number of rotations when arranged on the optical axis of the projection lens. This distance measuring operation is performed by the integration capacitor
After turning off the set switch 46, the IRED1 is pulsed.
And the integrated voltage generated at the capacitor 45 at this time is
The CPU 12 receives an input from the built-in A / D converter.
You. This integrated voltage is the collector current of transistor 42
I_ATherefore, according to the equation (11), the CPU 12
Calculates the subject distance L₇Can be calculated
Wear. Next, the end rotation speed of the IRED1 scan
N_φAnd N (step S9), and N ≠ N₀If
(NO), the process returns to the step S4, and the peak detecting operation is performed again.
Repeat. However, in step S9, N = N₀If
(YES), a predetermined amount of scan of IRED1 is detected,
The motor 20 is stopped (step S11), and the peak is detected.
Is performed (step S12). Then, the presence or absence of a peak is determined (step S1).
3) If there is a peak at this time (NO), the above-mentioned glass
As shown in FIG.
Infinity assuming shooting of scenery from the car window as in (a)
Focus on the subject (step S16)
Unnecessary strobe light is turned off (step S17). Soshi
To determine whether the second release switch is on or off (the
Step S18) At the time of input (YES), exposure is performed (step S18).
Step S20), the motor 20 is rotated in reverse (step S2).
1), IRED scan position reset switch on (switch
Operate until step S22) and stop the motor 20
(Step S23), the photographing sequence ends. Ma
When it is determined that there is no peak in step S13
Is not shooting through glass (YES)WhenJudged, ahead
Focusing is performed according to the distance measurement result LC obtained at
(Step S14), whether the strobe is on or off
Automatically determined from the brightness of the film and the film speed
The robot follows the robo mode (step S15). That
The subsequent sequence performs the same operation as when judging through glass.
No, the shooting sequence ends. In step S18, the second time
If the release switch is off (NO), step S
By the judgment of 19, the first release switch is turned on.
As long as there is, it keeps turning in steps S18 to S19, 2nd
Wait for the release switch input. 1st release on the way
When the switch is turned off, the process returns to step S1 to change the composition.
Etc. can be reset. Control of these series of operations is performed by CP
This is performed by U12. In actual photographing, FIG.
Not only the photographing through the glass shown in FIG.
When shooting a mannequin in a shop window like
There is also. FIG. 6 shows such a camera mounted on a camera.
9 shows a configuration of a distance measuring apparatus according to a second embodiment in which a shadow is realized. here
Therefore, the same reference numerals are used for members equivalent to those in FIG.
Reference numerals are given and the description is omitted. The second embodiment is different from the configuration of FIG.
The difference is that an AC light detection unit 53 is additionally provided.
Has become. The AC light detection unit 53 enters the PSD 4
This circuit detects the presence or absence of an AC light component in the emitted light.
Then, take out the output of PSD4 with a high-pass filter,
It is assumed that the circuit is determined by an comparator or the like. Referring to the flowchart of FIG.
The operation of the second embodiment will be described. Here, FIG.
In the chart, from step S31 to step S4
The operation up to 2 (peak detection) corresponds to the flow of FIG.
Steps S1 to S12 of the chart (peak detection
The description is omitted because it is equivalent to the operation up to
Only the characteristic portions will be described. Step S43Peak of peak detection performed in
Is determined (step S4).4), Peak at this time
If (NO), as described above, the AC light is detected by the AC light detection unit.
Detection (step S46), and when AC light is detected,
(Step S47) Artificially illuminated by AC illumination
L6 is determined as shooting through the show window
Calculate and add the distance of 50cm to the object distance.
(Step S48). This subject distance is
IRED position N when a peak occurs due to peak detection
Is obtained, and the reflected signal light incident position x6 at this time (this
Is determined by S7a.)
Calculate L6 according to and add 50cm to it.
You. The 50cm is the window glass
And the average distance that the product is placed
is there. Therefore, the added distance is limited to 50 cm
Not. When the second release switch is turned on,
Off is determined (step S50).
S), exposure is performed (step S51), and the motor 20 is rotated in the reverse direction.
(Step S53), IRED scan position reset
Operate until switch-on (step S54)
The photographing sequence is stopped (step S55).
finish. In step S47 described above,
When no AC light is detected (NO), this is within the shooting range
It is assumed that AC light is not included in the
(Step S49). Here as shown in FIG.
Are displayed in the viewfinder by the display units 13 and 55.
Detecting C light (photographing through a show window) to photographers
You may make it notify. However, in this embodiment, the show
Assuming that the image is taken from the front of the window glass
ing. The subsequent sequence is performed when judging through glass.
The same operation as described above is performed, and the photographing sequence ends. The presence or absence of the peak in step S43
When it is determined that there is no peak (YES),
Judgment not taken through the shop window
Distance measurement result L_CFocus according to (Step
S14). Subsequent sequence is when judging through glass
The same operation as described above is performed, and the photographing sequence ends. In step S50, 2n
d If the release switch is off (NO),
The first release switch is turned on by the determination in step S52.
Between the steps S50 and S51
Continue turning and wait for the input of the 2nd release switch. On the way
When the 1st release switch is turned off at step S1,
To reset the composition and the like. A series of these
The operation is controlled by the CPU 12. Next, as a third embodiment, as shown in FIG.
Scenes that capture subjects that are not landscapes, even outside the car window
Distance measurement device that does not erroneously measure the distance so that the
explain about. This distance measuring device has a central photometer shown in FIG.
50, a peripheral photometer 51 is additionally provided.
Then, whether or not these circuits determine backlighting,
Switch focus position after judging through glass
It is. This backlight determination is performed in a configuration as shown in FIG.
It is realized by a circuit. In this backlight determination circuit, the light receiving section has a focal length.
Separation f_EAnd the diameter d of the central part_SThe spot
G-side light part and average photometry part with a larger area at the outer periphery
And two divided light receiving elements 61. The average
The photometric section is one side d_aWith a length of almost
arctan d_a/ F_SMetering
And the spot metering unit measures a fraction of the range.
It is configured as follows. The output current of this light receiving element 61
Is integrated by the capacitors 62 and 63. This product
Minutes before the integration C reset switches 64 and 65 are turned off.
CPU 12 turns off these switches.
After that, the comparators 66 and 67 for comparing with a predetermined voltage
To detect whether it reverses after a long time
Measurement of the amount of light incident on these light receiving elements.
Can be. FIG. 10(B)And FIG.(A)Shooting situation
As can be seen by comparison, FIG.(B)Is backlit
Easy to be. 9 flowchartSecondOperation of the third embodiment
The work is shown and explained. The operation of the distance measuring apparatus of the third embodiment is the same as that of the second embodiment.
This is almost the same as the flowchart of FIG.
Photometry is performed prior to detection of the
Step S74), and AC light is detected in step S79.
When there is no backlight (NO), the backlight determination circuit shown in FIG.
It is determined whether or not there is backlight (step S81), and it is determined that the subject is backlit.
At the time, as described with reference to FIG.
₆Is calculated, and the distance is set by adding 50 cm.
However, when it is determined that the subject is not backlit, the subject distance is set to infinity.
, And thereafter, the same operation as that described with reference to FIG. 7 is performed. In the backlight judgment of step S81,
When the brightness is low enough to require a strobe light,
Landscape cameras cannot shoot landscapes, and
Since the probability of being over the lath is considered even lower,
It may be purely at the time of spot metering and low luminance. As a fourth embodiment, an apparatus shown in FIG.
In front of each of the taking lens and the flash
Embodiments in which a polarizing filter is provided are also possible. [0086] A garble like the photographing situation shown in FIG.
When shooting through the flash when shooting through
Light specularly reflected by the camera enters the photographic lens, making it difficult to see
The blur will be left in the photo. FIG. 11 (a) shows the appearance of the camera.
The camera body 71 includes a photographing lens 71 and a strobe light emitting section 7.
2. The finder objective lens 73 and the shutter button 74
Is provided. 11 (b) and 11 (c).
Cover the front of the flash 72 and the taking lens 71
Are provided with polarizing filters 75 and 76. Then, when detecting through the glass, automatically
As shown in FIG. 1B, the photographing lens 71 and the strobe light are emitted.
By covering the front of the part 72 and photographing, as shown in FIG.
As described above, the blur due to the reflected light is removed from the image. Toes
And the polarization directions of the polarization filters 75 and 76 are made orthogonal to each other.
By doing so, the glass surface is positive without changing the polarization direction.
Reflected light, reflected light from the glass enters the taking lens
do not do. Next, FIG. 12 shows a fifth embodiment of the present invention.
The configuration of all the distance measuring devices will be shown and described. This distance measuring device
Is to provide a drive mechanism on the IRED1 and make it movable
, And a scan mechanism in the other direction
This is an example in which the AF was achieved. In this distance measuring device,
3 is arranged in the vertical direction of the camera body and scans in the y direction.
The motor mechanism comprises a motor 85, a movable part 86, and a feed screw 84.
And driven and controlled by the motor driver 10a.
You. This is the same configuration as the through-glass detection mechanism in FIG.
You. The IRED 1 is located above the movable part 86.
Part is fixed to a member 82 movable in the x direction,
83, the feed screw 81 and the motor driver 10b,
You can scan. The IRED 1 moves (scans) by this mechanism.
12), the light is projected as shown in FIG.
Since the direction changes in the range of x, the viewfinder screen
The light for distance measurement moves in (photographing range) as shown in FIG.
Then, distance measurement of a plurality of points on the screen becomes possible. However, the book
In the embodiment, the PSD 4 is a scan of the IRED in the x direction.
The width must be large enough to cover the
You. Further, the configuration of the distance measuring apparatus shown in FIG.
Also, the scanning position of IRED and the signal of PSD4
Since triangulation can be performed using the light incident position,
H AF can also be performed. Next, FIG. 13 shows a sixth embodiment according to the present invention.
A configuration of a distance measuring device as an example will be shown and described. This rangefinder
The photodiode is an adjacent photodiode instead of PSD4
Distance measurement and peak detection are performed by the outputs of 4a and 4b.
Things. The boundary between the photodiodes 4a and 4b
Is placed on the optical axis of the light receiving lens, as shown in FIG.
And the spot 1a of the reflected signal light is
From the IRED position x when equally incident on the
The distance of the object 7 can be obtained. This is shown in FIG.
It is clear from (a) that both photodiodes 4a, 4b
If these outputs are equal, will these differences be "0"?
A light amount detector is provided for each of the photodiodes 4a and 4b.
Attach 90, 91, take difference by differencer 92, add
So that the sum of these can be obtained in the container 93.
For example, the CPU 12 measures the distance and peaks from these outputs.
Knowledge can be easily performed. Referring to the flowchart of FIG.
The operation of the distance measuring apparatus thus configured will be described. First, the presence or absence of the input of the first release switch
Nothing is detected (step S91), and the IRED1 is moved (scanned).
(Canning) is started (step S92). At this time
The CPU 12 always monitors this scanning position x.
I am doing it. Then, the above-described sum and difference of light amounts are detected.
No (steps S93, S94), if this difference is "0"
In this case (step S95), from the scan position x at this time,
Since the subject distance is obtained, x at this time is x₀To be
(Step S96). Next, the scanning of the IRED 1 is
Moving width limit x_MAX(Step S)
97). After the scanning is completed, the scanning position x
And a peak signal is detected from the sum signal (step S9).
8). Then, the presence or absence of a peak is determined (step S
99) If a peak is detected here,
X in the raw position₀(Step S100),
The focus position described with reference to FIG. 7 is calculated according to equation (3).
(Step S101). But in step S99
When there is no peak, (8)
The distance measurement calculation according to the equation is performed (step S102). Next, it is detected that the second release switch is turned on.
If it is issued, focus is performed with the subject distance set to L.
(Step S105), exposure is performed (Step S106),
The IRED position is reset (step S107), and the
End Kens. In this embodiment, the distance measurement shown in FIG.
Even without using a complicated distance measuring circuit like a device,
Distance measurement becomes possible only by detecting the difference. Next, FIG. 15 shows a distance measurement as a seventh embodiment.
The configuration of the device will be shown and described. This embodiment is different from the above-described embodiments.
No moving part is required, and a gas as shown in FIG.
When shooting a subject over a glass, the photographer
Shoot photos without erroneous distance measurement by operating the mode button 19
Is what you do. This distance measuring device includes the light emitting and receiving lenses 2 and 3
On the side, IRED1 for detection through glass and for distance measurementa, 1,
And photodiodes 4a, 4One by one
The IRED 1a is displaced from the optical axis of the
A photodiode (PD) 4a farther from the light side
Is located farther from the light emitting side than the receiving lens optical axis.
Is placed. Therefore, when the IRED 1a is turned on, FIG.
Distance L of position as in (a)₆If there is glass 6
The reflected light of the light enters the PD 4a. In this state, distance measurement is performed from the optical axis of the projection lens.
When the IRED 1 is projected, it is near the optical axis of the light receiving lens.
The regular reflection light from the glass 6 enters the PSD 4 geometrically.
The light for distance measurement passes through the glass 6 and
The projected and reflected signal light only penetrates the glass 6 and
It is incident on SD4. Therefore, in this embodiment, as shown in FIG.
The light amount detection unit 9 is connected to the PD 4a,
The result is compared with the reference signal by the comparator 9a.
You. Strong light is emitted to the PD 4a by the comparator 9a.
When the input is detected, the CPU and the display unit 13
Therefore, the finder display 13a is turned on. Photographer
If you turn on the 2nd release switch 17 in this state,
Good. Referring to the flowchart of FIG.
The operation of the distance measuring apparatus thus configured will be described. First, whether or not the first release switch is on
Is detected (step S11), and the photographer
This operation is performed when searching for a shooting position through the camera. The photographing mode through the glass is set by the switch 19.
Is selected (step S112), the fine
The display 13a in the printer is blinked (step S118). This
In the state of, the photographer changes the camera position and
Search for This position is as shown in FIG.
Glass is a predetermined distance L₆It is the position that becomes. Next, the IRED 1a is caused to emit light, and the light amount is detected.
An exit is performed (step S119). Then, as shown in FIG.
In the same way as in the peak detection, strong direct reflection light is incident on PD4a.
To determine whether or not the
The quasi-light quantities are compared (step S120), and the detected
If larger (YES), display 13 in viewfinder
"a" is changed from blinking to lighting (step S121). this
Inform the photographer that the distance measurement is possible by the lighting condition.
You. However, in the determination in step S120, the detected light amount is
If smaller than the threshold (NO), the process returns to step S111.
The display 13a blinks. Following S59, at S52 the IR for distance measurement is used.
The ED 1 is received by the light emitting PSD 4 to perform distance measurement. Then, the IRED 1 is caused to emit light to perform distance measurement.
(Step S113), the second release switch is turned off.
Is detected (step S114), and the distance measurement result L
The subject is focused (step S116), and exposure is performed (step S116).
(Step S117) The sequence ends. In step S112, detection through glass is performed.
If no mode is selected (NO), immediately
The distance is measured by causing the IRED 1 in step S113 to emit light.
It works similarly. The detection mode through glass of this embodiment is selected.
If not, shooting through glass is likely to fail
However, a scanning mechanism is required compared to the previous embodiment.
It is not necessary, and accurate distance measurement is possible even through glass.
There are many fruits. As described above, the distance measuring apparatus of the present embodiment
According to the conventional active AF, the erroneously measured
Focus on the correct subject distance even when shooting over a lath
Can be provided at a low price. The present invention is limited to the embodiment described above.
It does not depart from the gist of the invention.
Of course, various modifications and applications are possible. [0094] According to the present invention, as described in detail above,
The invention uses the reflected light of glass or the like when measuring the subject distance.
Erroneous distance measurement, simple structure and low costEquipped with a distance measuring device
CameraCan be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram for explaining the concept of the principle of detecting through glass by a distance measuring apparatus of the present invention. FIG. 2 is a diagram showing a configuration of a distance measuring device mounted on a camera as a first embodiment according to the present invention. FIG. 3 is a diagram illustrating a specific configuration of a scanning unit, a distance measuring unit, and a light amount detecting unit of the IRED 1 illustrated in FIG. 2; FIG. 4 is a flowchart for explaining the operation of the distance measuring apparatus shown in FIG. 2; FIG. 5A is a diagram illustrating a state of shooting through glass, and FIG. 5B is a diagram illustrating a state of shooting an object or the like in a show window. FIG. 6 is a diagram showing a configuration of a distance measuring apparatus as a second embodiment according to the present invention. 7 is a flowchart for explaining the operation of the distance measuring apparatus shown in FIG. FIG. 8 is a diagram showing a specific configuration of the backlight determination circuit shown in FIG. 6; FIG. 9 is a flowchart for explaining the operation of the distance measuring apparatus of the third embodiment. FIG. 10 is a diagram showing a shooting situation of shooting through glass. FIG. 11 is a diagram showing a configuration of a distance measuring apparatus as a fourth embodiment according to the present invention. FIG. 12 is a diagram showing a configuration of a distance measuring apparatus as a fifth embodiment according to the present invention. FIG. 13 is a diagram showing a configuration of a distance measuring apparatus as a sixth embodiment according to the present invention. FIG. 14 is a flowchart for explaining the operation of the distance measuring apparatus shown in FIG. FIG. 15 is a diagram showing a configuration of a distance measuring apparatus as a seventh embodiment according to the present invention. FIG. 16 is a flowchart for explaining the operation of the distance measuring apparatus shown in FIG. [Description of Signs] 1 ... light emitting element (IRED), 2 ... light emitting lens, 3 ... light receiving lens, 4 ... light position detecting element (PSD), 5 ... AFI
C, 6: glass, 7: subject, 8: distance measuring section, 9: light quantity detecting section, 10: driver section, 11: scanning section, 12: C
PU, 13: display unit, 14: strobe unit, 15: lens extension unit, 16, 17: switch.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02B 7/32 G03B 13/36

Claims (1)

(57) [Claim 1] A camera having a distance measuring device for projecting light onto a subject, receiving reflected light from the subject, and performing focusing , emits light for distance measurement. Distance measuring light projecting means, and subject reflected light by light emitted from the distance measuring light projecting means.
A distance measurement light receiving means for receiving, through glass that projects the projection light different directions for the distance measuring
The light emitting means for detection and the light receiving means for distance measurement are arranged at different positions.
I, glass reflected light receiving means provided in a position such as to receive light reflected by the glass of the projected light by the glass over detecting light projecting means, the detected quantity of detected light at the glass reflected light receiving means Comparing means for comparing the magnitude of the light quantity with a predetermined reference light quantity, and when the detected light quantity is larger than the reference light quantity by the comparison by the comparing means , the camera can reduce the influence of the glass reflected light.
A camera comprising display means for notifying that the user is at a position where distance measurement is not possible.