JPH01284812A - Rangefinding device for single-lens reflex camera - Google Patents

Abstract

PURPOSE:To accomplish multipoint rangefinding with a simple constitution by providing a sub mirror consisting of plural reflecting parts for dividing a photographed image plane into plural rangefinding visual fields and controlling deflection so that rangefinding luminous fluxes from the respective reflecting parts are made incident on a specified position on a rangefinding sensor. CONSTITUTION:The rangefinding luminous flux transmitted through the aperture part of a quick return mirror 1 which is made to be up at the time of photographing and down at the time of rangefinding is made incident on the sub mirror 4. The sub mirror 4 is provided with four reflecting parts 4b-4e on the up-and-down and right-and-left sides of the reflecting part 4a which is a central rangefinding point and constitutes a concave spherical mirror as a whole, then it can turn on a hinge 5. The luminous flux reflected by the sub mirror 4 is conducted to the rangefinding sensor 7 through a variable apex angle prism 6 and the rangefinding luminous fluxes from the respective reflecting parts 4a-4e are controlled to be made incident on the specified position on the rangefinding sensor 7 by controlling the angle of the variable apex angle prism 6. Thus, multipoint rangefinding in the photographed image plane can be performed.

Description

Detailed Description of the Invention (Field of Application of the Invention) The present invention relates to a single-lens camera that performs distance measurement using a beam of light that passes through a portion of a main mirror (click return mirror) and enters a distance measurement sensor via a sub mirror. This invention relates to a distance measuring device for reflex cameras.

(Background of the Invention) Conventionally, single-lens reflex cameras equipped with this type of optical system have been commercially available from various companies. However, all of these systems use a precisely adjusted sub-mirror to collect the light beam that has passed through the center of the click-return mirror into the distance measurement sensor (
AF sensor), so there was a drawback that distance measurement (focus detection) could only be done for a small part of the pattern in the center of the screen.Originally, the shooting screen was used to express and confirm the intention of the drawing. Being able to only measure the distance at the center (not being able to focus) like this is inconvenient as it requires preparations such as pre-focusing before framing, and also makes it difficult to make preparations. I tended to neglect the important framing because of the amount of work involved.

As a countermeasure to the above, it seems that attempts have been made to make it possible to measure distances other than the center of the screen by devising the secondary mirror. In this type of optical system, which requires optical precision, it is extremely difficult to achieve this, and as of now, no proposal has been made to make this possible.

(Object of the Invention) An object of the present invention is to provide a distance measuring device for a single-lens reflex camera that can perform multi-point distance measurement with a simple configuration.

Another object of the present invention is to enable multi-point distance measurement with a simple configuration, to check whether the position of the secondary mirror is appropriate, and to automatically calibrate the positional error. An object of the present invention is to provide a distance measuring device for a single-lens reflex camera.

(Features of the Invention) In order to achieve the above object, the present invention comprises a sub-mirror including a plurality of reflecting sections that divide the photographing screen into a plurality of distance measuring fields, and each of the plurality of reflecting sections A deflecting means is provided for deflecting the distance measuring light flux from the reflecting part so as to be incident on a predetermined position on the distance measuring sensor, and the distance measuring field of view within the photographing screen is selected by deflection control by the deflecting means. It is characterized by what it did.

Further, an optical signal generating means configured integrally with the sub mirror and generating an optical signal, and a position detecting means detecting the current position of the sub mirror from the optical signal from the optical signal generating means are provided. , characterized in that the current position of the secondary mirror is confirmed.

Further, an optical signal generating means configured integrally with the sub mirror and generating an optical signal, and a position detecting means detecting the current position of the sub mirror from the optical signal from the optical signal generating means;
A fine adjustment means is provided for comparing the position information from the position detection means with the reference position information and finely adjusting the deflection means based on the error information, thereby confirming the current position of the secondary mirror and adjusting the reference position. The present invention is characterized in that the positional error of the sub-mirror due to the position is corrected by fine deflection adjustment of the deflection means.

(Embodiment of the Invention) Figures 1 to 3 are diagrams showing a distance measuring optical system that is an embodiment of the present invention, with Figure 1 being a side view and Figure 2 being a top view. . FIG. 3 is a view of the submirror as seen from the front, side, and bottom, respectively. In each of the above figures,
A known quick return mirror 1 is pivoted about a hinge 2 together with a mirror receiving plate 3, and is moved up during photographing (the state shown by the dotted line) and is moved down during distance measurement (observation).

The mirror receiving plate 3 is 3-1, 3-2 (see Figure 1) and 3-
3. It has an opening shown in 3-4 (see Figure 2),
The light beam transmitted through the quick return mirror 1 through this opening is incident on the sub mirror 4.

The sub-mirror 4 has a reflecting portion 4a serving as a central distance measuring point, a reflecting portion 4b serving as an upper measuring point, a reflecting portion 4c serving as a lower measuring point, a reflecting portion 4d serving as a right measuring point, and a reflecting portion 4d serving as a left measuring point. As can be seen from FIG. It is rotatably supported by a hinge 5 provided on the back surface. The light beam reflected by the sub-mirror 4 is directed to a distance measurement sensor 7 via a variable apex angle prism 6 arranged approximately at the second imaging plane so that aberrations such as color caused by the prism hardly affect distance measurement. be guided. The variable apex angle prism 6 is made up of an upper glass 6a, a lower glass 6b, and a liquid or a viscoelastic material such as silicon injected between them. The luminous flux from one of the reflecting portions (distance measuring points) is guided to the distance measuring sensor 7.

The reflecting member 8 is used together with the light source 9 and the projection lens 10 to correct the shift of the down position of the sub mirror 4. In other words, when the sub mirror 4 is a polygonal mirror, the sub mirror 4 itself only rotates. However, since the sub mirror 4 is pivoted by the rotatable click return mirror 1, it is difficult to maintain a predetermined angle in the down position over time, and this is to correct this. It is constructed integrally with the sub-mirror 4 and in a horizontal design. In Fig. 1.2, 11 is a surface equivalent to a film surface, 12 is a shutter section for controlling exposure, 13 is a photographing optical axis, and 14 is a known focus plate surface.

In the above distance measuring optical system, in order to guide the image reflected on the reflection part 4a to the distance measuring sensor 7 when measuring the distance at the center of the screen, the variable apex angle prism 6 is horizontal in the left and right direction, and the rear side in the front and back direction is approximately 20 mm. When measuring the distance above the screen, the variable apex prism 6 is horizontal in the left and right direction, and the rear side is approximately The variable apex prism 6 is controlled at an angle raised by 35 degrees.When measuring distance to the right side of the screen, the left side of the variable apex prism 6 is raised approximately 20 degrees in the left-right direction in order to guide the image reflected on the reflection section 4e to the distance measurement sensor 7. The angle is controlled so that the rear side is raised by about 20 degrees in the front-back direction.When measuring the distance from the bottom of the screen, the variable apex angle prism 6 is controlled to the left and right in order to guide the image reflected on the reflection part 4c to the distance measurement sensor 7. The variable apex prism 6 is controlled to be in a horizontal state both in the horizontal direction and in the front and back directions.When measuring distance to the left side of the screen, the variable apex angle prism 6 is set so that the right side is approximately 20" in the left and right direction in order to guide the image reflected on the reflection section 4d to the distance measurement sensor 7. The raised angle is controlled so that the rear part is raised by approximately 20 inches in the front-rear direction.

The above is the control performed when selecting the distance measuring optical path, but this alone is not sufficient to correct the positional deviation of the sub mirror 4, as described above. That is, for example, the secondary mirror 4 is
When deflected downward, the light directed to the same position on the film surface will be tilted by 2 degrees when reflected by the sub mirror 4. For this reason, the viewing angle of the distance measurement sensor 7 viewing through the variable apex angle prism 6 is deviated by 2'', making it impossible to perform correct distance measurement (focus detection).

Therefore, in this embodiment, the deflection angle of the sub mirror 4 is detected using the reflection member 8, the light source 9, and the projection lens 10, and its correction (hereinafter referred to as calibration) is performed by changing the angle of the variable apex prism 6. I try to do it. In the above example, the deflection of the sub mirror 4 is corrected by calibrating the angle of the variable apex prism 6 by 2'', and the angle at which the distance measurement sensor 7 views the lens is adjusted to the design value. The relationship between No. 7 and the film surface is approximately 0.5 mm vertically and approximately 0.01 mm in focus.
It will be shifted by mm. In this case, this vertical deviation is small compared to the distance measurement range and is ignored because it is small compared to the distance between the selected multipoint distance measurements, while the focus deviation is
AP adjustment is performed by correcting the distance measurement value based on the "angular shift vs. focus shift" data stored in M.

FIG. 4 shows an example of a circuit configuration for executing the various controls described above. In the figure, 21 photoelectrically converts the signal from the distance measurement sensor 7 to calculate distance measurement information, and also performs calibration. A distance measuring circuit 22 outputs photoelectric conversion information (image signal) of the reflected light from the sub mirror 4 of the light source 9, and is turned on when the film is replaced, the battery is replaced, or by an intentional operation by the user. Switch for automatic calibration of secondary mirror 4, 23
24 is a signal generation circuit that generates a distance measurement area position signal indicating whether the distance measurement area (range measurement point) has been selected; and 25 is focal length information of the attached lens. 26 is a reference distance information generation circuit that generates information of 150+nm as the reference distance to the exit pupil, 27 is an addition circuit, and 28 is a switch that switches to a state inversely proportional to the on/off state of the switch 22. , 29 is an AF drive circuit, 30 is a peak position detection circuit that detects the peak position (pixel position) of the image signal, and 31 is a central pixel position that generates information indicating the central pixel position in the pixel column direction forming the distance measuring sensor 7. An information generation circuit, 32 is an up/down counter, 33 is a comparison circuit, 34 is a light amount detection circuit, 35 is a peak detection circuit that detects the peak time of the signal from the light amount detection circuit 34, and 36 is a signal line a at a high level. a sawtooth wave generation circuit that starts operating together with the up/down counter 32 and the peak detection circuit 35;
37 is a latch circuit, 38 to 42 are AND gates, 43 is a converging calculation circuit, 44 is an inverting amplifier circuit, 45 is a switch that switches according to the output of the AND gate 42, and 46 holds various data. ROM, 48.49
50.51 is an adder circuit, 50.51 is a diode, 52 is a pull-down resistor, 53.54 is a drive unit for changing the angle of the variable apex angle prism 6 vertically and horizontally, and 55.56 is a circuit that has a higher level than the AND gates 38 and 39. This is a switch that turns on when the signal is output.

Next, the operation will be explained. In this embodiment, when the sub mirror 4 is calibrated, each output of the AND gates 40 to 42 is "
0” 0 “O”, and “1” 1” “O” or “1” 1” 1” for center distance measurement without calibration, “1” 0” 1” for upward distance measurement, and “1” 0” 1” for downward distance measurement. Sometimes “1” “O”
The signal generation circuit 24 generates a signal that is "0", "O"1""O" during left distance measurement, and "0"1"1" during right distance measurement.
(The configuration will be described later), and each signal at the time of non-calibration is given as an upper address of the ROM 46.

The ROM 46 receiving this signal selects one of the six ranges (5 range measurement areas + 1 calibration area) from the upper address, and selects the horizontal angle setting information of the variable apex prism 6,
It outputs the angle setting information in the front and rear directions, the selected distance measurement area (=reflection part), and a focus shift amount signal based on the calibration deflection.

Further, the calibration information is given as a lower address of the ROM 46.

First, the operation of the sub mirror 4 during calibration will be described.

As mentioned above, this is necessary to realize such a highly accurate system with a relatively simple mechanism and correction mechanism. The process starts when the switch 22 is turned on. That is, when the switch 22 is turned on, the signal line a becomes high level, the light source drive circuit 23 is activated, and the calibration light source 9 is turned on. Also, since the signal line a becomes high level, the AND gate 40
The outputs of 42 to 42 become O"0"O", which tells the ROM 46 that the sub mirror 4 is being calibrated. In this state, the light projected by the light source 9 is transmitted to the projection lens 1.
A reflective member 8 integrally provided to the sub mirror 4 via 0
, and is substantially focused on the distance measuring sensor 7 via the variable apex angle prism 6.

If the secondary mirror 4 is tilted in the front-rear direction, the incident position of the spot light from the reflection member 8 will be shifted from the center position of the distance measurement sensor 7 in the width direction (perpendicular to the pixel row), and the distance measurement The total amount of light reflected on the sensor 7 decreases. In other words, this means that when the angle of the variable apex angle prism 6 is set so that the amount of light output from the distance measurement sensor 7 is maximized, the reflected light from the sub mirror 4 of the light source 9 is captured. This means that it was done properly. As an example,
When the sub mirror 4 is tilted by 1 degree from the predetermined position, the amount of light becomes maximum when the angle of the variable apex angle prism 6 is tilted by 2 degrees. Therefore, by adjusting the angle of the variable apex angle prism 6 based on the output of the distance measuring sensor 7 at this time, accurate calibration control of the sub mirror 4 becomes possible. This control is performed as follows.

The image signal (reflected light from the light source 9) photoelectrically converted by the distance measurement sensor 7 is inputted from the distance measurement circuit 21 to the light amount detection circuit 34, and peak detection is started by the next stage peak detection circuit 35. . Also, at this time, a sawtooth wave is generated in the sawtooth wave generation circuit 36, and this signal is input to the ROM 46 via the latch circuit 37, so that the angle adjustment start information of the variable apex angle prism 6 is outputted from the ROM 46. The variable apex angle prism 6 is moved so that its angle is tilted in the front-back direction. While this operation is being performed, the peak detection circuit 35 performs peak detection (detection of the point in time when the amount of light reaches its maximum), and when a peak detection signal is output from the circuit, the latch circuit is activated. The angle of the variable apex angle prism 6 is input in the form of a lower address in the ROM and is stored.

Further, if the secondary mirror 4 is tilted in the left-right direction, a similar problem occurs. In this case, the light reflected by the sub mirror 4 swings left and right, and the spot position on the ranging sensor 7 also swings left and right (in the pixel row direction). The circuit that detects the peak pixel position at this time is the peak position detection circuit 30, and the peak pixel position detected here is compared with the center pixel position from the center pixel position information generation circuit 31 in the comparison circuit 33. Alternatively, if the swing is to the right, a high level or low level error signal is outputted from the comparison circuit 33 to the up/down counter 32, thereby adjusting the horizontal angle of the variable apex angle prism 6 via the ROM 46. is started. Thereafter, when the output of the comparison circuit 33 becomes zero, the up or down count value at that time is held in the up/down counter 32, and the count value at this time is inputted in the form of a lower address of the ROM 46 and held. As a result, the angle of the variable apex prism 6 (calibration of the sub-mirror 4 in the left-right direction) has been adjusted so that the spot light from the light source 9 is incident on the central pixel position in the pixel row direction of the distance measurement sensor 7. become.

Next, the angle adjustment control of the variable apex angle prism 6, which is changed according to the distance measurement area selection, will be described.

For example, the signal for performing distance measurement above the screen is sent to the signal generation circuit 24.
If the output is from the AND gates 4o to 42, R
A signal of "1", "0", and "1" is input to the OM46. Then, the ROM 46 receiving this signal stores the angle setting information of the variable apex angle prism 6 held in advance, that is, in this embodiment, in order to guide the image reflected on the reflection section 4b to the distance measuring sensor 7.
Angle setting information is output so that the variable apex angle prism 6 is horizontal in the left-right direction and the rear side is raised by about 35 degrees in the front-back direction. As a result, the variable apex angle prism 6 receives correction information based on the lens pupil position, which will be described later, into the adding circuit 4.
After adding in step 8, the above-mentioned calibration control is performed (
Angle setting is performed by the drive unit 53 based on the angle). In other words, if the correction information based on the lens pupil position is zero at this time, the angle is set such that the rear is raised by about 356 points in the front-rear direction with respect to the calibrated state.

At the same time, from the ROM 46, the amount of defocus (amount of defocus due to the selected ranging area and calibration deflection) based on the "angular deviation vs. defocus" data stored in the ROM at the time of design is sent to the adder 27. The adder 27 adds the distance measurement signal from the distance measurement circuit 21 and sends the normalized distance measurement information to the AF drive circuit 29 via the switch 28, where the AP adjustment of the lens is performed. be exposed.

It goes without saying that either of the above-mentioned calibration control and angle setting control may be performed first.

Next, we will discuss lens pupil correction. In the case of TTL distance measurement, all light is provided through the photographing lens. Therefore, in order to measure distance 1" at the center of the screen, the camera must be configured to aim at the optical axis correctly. This is especially true when using a dark (large F-number) lens, where the distance measuring optical axis is tilted to the right, for example. If this happens, an imbalance will occur in which the distance measuring light beam aiming at the right exit pupil will be eclipsed by the lens exit pupil, and the distance measuring light beam aiming at the left exit pupil will not be eclipsed.

This has the disadvantage that, in the case of an AF method based on the amount of deviation that compares multiple images from the left and right exit pupils, the comparison is not performed correctly. Therefore, sufficient adjustments have been made in this type of device.

However, in the case where distance measurement is possible in areas other than the center of the screen as in this embodiment, since the lens optical axis and the axis of symmetry of the distance measurement light beam are not parallel, correction is required during such distance measurement. In other words, even when measuring a point on the left side of the film surface, the left and right distance measuring light fluxes to that point must be symmetrical with respect to the optical axis on the exit pupil of the lens. This is because if the axis of symmetry of the distance-measuring light beam is parallel to the lens optical axis, that is, perpendicular to the film surface, the distance-measuring light beam on the left side will be vignetted at the exit surface of the lens. Also, if the exit pupil position of the lens is far from the symmetrical axis of the ranging beam,
On the exit pupil plane of the lens, contrary to the above, the distance measuring light beam on the right side is vignetted. For this reason, in multi-point distance measurement, the distance measurement light flux must have a converging shape so that the symmetry axes of the distance measurement light beams at each point coincide on the exit pupil plane of the lens. This requires changing the convergence angle depending on the exit pupil distance of the lens. Therefore, in the present embodiment, in case exit pupil plane position distance information is difficult to obtain, correction control is performed using equivalently an easily available lens focal length signal. Due to the thermal lens configuration, the focal length of the lens is different from the exit pupil distance. However, in the case of interchangeable lenses for eye reflex cameras, the exit pupil plane is farther away than the replacement mount, and there are few lenses that are extremely dark from wide-angle to medium telephoto, that is, have small exit pupil diameters. That's what I do.

That is, the focal length information of the currently attached lens outputted from the focal length information generation circuit 25 and the larger distance information of r150mmJ outputted from the reference information generation circuit 26 are selected by the diodes 50 and 51.
The tip taper angle calculation circuit 43 calculates the tip taper angle α using the following formula.

α=tan −' (f!, /L) Here, °C is the distance from the optical axis to the incident position of the ranging light beam during ranging other than the center ranging, that is, for example, in the case of left ranging, the film It is the distance between the corresponding point on the surface and the center point of the film surface, and L is the focal length information of the currently attached lens and r
150 mm, which is the larger value of the distance information.

The tip convergence angle information calculated as described above is input to the switch 45, where it is input as information as is or as information via the inverting amplifier circuit 44, depending on the ranging area selected at that time. Output. In other words, for example, if the upper or right distance measurement area is selected, the AND gate 42
Since the output of is "1", the switch 45 is switched to the output side of the inverting amplifier circuit 44, and the leading edge narrowing calculation circuit 43 is switched to the output side of the inverting amplifier circuit 44.
In other words, the information that is inverted and amplified is output to the next stage as negative convergent angle information (-α). Since the output of the gate 42 is "0", the switch 45 is switched to the state shown in FIG. +α) and output to the next stage.

This positive or negative convergence angle information is then input to switches 55 and 56 whose on/off is controlled by the output of AND gate 38 or 39.

Here, when the left or right range-finding area is selected, the AND gate 38 outputs a high level, turning on the switch 55, and the AND gate 39 selects the upper or lower range-finding area. When is selected, its output becomes high level, turning on the switch 56. Therefore, for example, if right distance measurement is currently selected, the switch 45 is switched to the output side of the inverting amplifier circuit 44, and the switch 55 is turned on at this time, so the negative The blurring angle information is input to the addition circuit 49, and the RO
The result of subtracting the positive angle setting information from M46 by this negative tip convergence angle information is output from the adding circuit 49, and as a result, the variable apex angle prism 6 is set to the negative tip by the drive unit 54. The angle is corrected so that the ranging light beam is directed inward by the convergence angle information. Furthermore, if downward distance measurement is selected, the switch 45 has been switched to the state shown in FIG. The result of adding the negative angle setting information from the ROM 46 to the positive convergent angle information is input to the adding circuit 48, and the result is output from the adding circuit 48. As a result, the variable apex angle prism 6 is The angle is corrected by the drive unit 53 so that the distance measuring light beam is directed slightly upward by the amount of positive convergence angle information.

Strictly speaking, it is necessary to correct the distance measurement position and the distance measurement result in conjunction with the correction based on the converging angle, but since the influence thereof is relatively small, it is not taken into consideration in this embodiment.

Further, in this embodiment, the difference between the distance measurement result on the variable apex angle prism 6 and the actual focus plane is as follows in terms of design.

r 6.6 mm at the center point on the film surface, r 7.2 mm J at the left and right points, and r 7.
6 mm J, and r5.5 mm J at the bottom point.

In the above embodiment, only the calibration associated with the angular error when the sub mirror 4 is brought down is performed, but if there is a high possibility of errors such as parallel shift, it is desirable to perform the following procedure.

FIG. 5 shows the state of this sub-mirror 110, and the same parts as in FIG. 1 are given the same reference numerals. Here, the light source 111 for calibration and the reflective member 112 are arranged in positions symmetrical to the light source 9 and the reflective member 8 for calibration, and the front view of the sub mirror 4 etc. in the normal position is the top left view in FIG. The diagram is as shown in the upper right figure.

Here, the lower right diagram shows a state where the sub mirror 110 has an angle (error) in the left and right direction. in this case,
The calibration light beam from the light source 9 is shifted to the right on the variable apex angle prism 6, and the calibration light beam from the light source 111 is also shifted by approximately the same amount in the same direction. The lower left diagram shows a state in which the sub mirror 110 has an error downward or forward.

In this case, the deviations between the light sources 9 and 111 are approximately the same amount in opposite directions.

FIG. 6 shows a configuration that can detect the above-mentioned state and cope with parallel shift, and the same parts as in FIG. 4 are given the same reference numerals.

The calibration operation by the light source 9 is almost the same. That is, until the peak detection signal is output from the peak detection circuit 35, the flip-flop 115 is in a reset state, so its Q output is at a high level, and since the signal line a is also at a high level during this sub-mirror calibration, an AND gate is applied. 11
The output of 6 becomes high level and up/down counter 3
2 is in an enabled state, and starts counting up or down while a high level or low level is input from the comparator circuit 33. During this time, angle adjustment start information for the variable apex prism 6 is outputted from the ROM 46 as described above.
The angle of the variable apex angle prism 6 is being moved. Thereafter, peak detection is performed by the peak detection circuit 35, and when a peak detection signal is output from the circuit, the flip-flop 11
5 is set and the Q output is inverted to low level, the value of the up/down counter 32 at that time is held, and the angle of the variable apex angle prism 6 at this time is input and held in the form of a lower address of the ROM. be done.

At the same time, since the Q output of the flip-flop 115 becomes high level, "1" is output from the OR gate 118, and as a result, signals "O", "O", and "1" are input to the ROM 46, and the light source 111 performs calibration. Move to mode. As a result, the ROM 46 outputs the angle adjustment start information of the variable apex angle prism 6 again, and the variable apex angle prism 6
The angle of is now moved so that it is tilted in the opposite direction from before.

Thereafter, the same operation as described above is performed by the up/down counter 3.
The angle of the variable apex prism 6 at the time of peak detection is also stored in the ROM.
is input and held in the form of lower-order addresses.

With the above configuration, the difference between the address from the up/down counter 32 and the address from the up/down counter 117 is used for calibration during distance measurement as the shift of the secondary mirror 110, and the sum is used for the same measurement as the angle of the secondary mirror 110. It is retained for distance calibration.

The above shows a simple shape for calibrating the secondary mirror, but it goes without saying that a completely three-dimensional six-coordinate degree of freedom requires similar measurements at at least one more location. However, in practice, the degree of freedom is small due to the support of the sub-mirror, the stopper, etc., so the amount of correction applied to each ranging point under the degree of freedom limited by such a calibration address can be set in design. Therefore, complete distance measurement using each correction amount can be achieved with a relatively simple mechanism.

Next, a case where the photographer selects a distance measurement area from the five points described above will be explained using FIG. 7.

FIG. 7 is a view from the front left of the camera grip, in which the photographer selects the distance measurement field of view selection mode using a dry selection member (not shown), and selects one of the five distance measurement points using the dial 130. You will have to choose the area. Said dial 13
0 is configured to be rotatable around a shaft 131, and has a click property due to click springs 132 and 133. This rotation of the dial 130 is converted into a rotational position signal with a 90° phase difference by an encoder board 134 and a brush unit 135. Further, in FIG. 7, 136 is a release switch, which allows an input to be made as to whether or not the distance measurement area selected by the dial 130 is to be taken into account in the multi-point evaluation distance measurement described later.

FIG. 8 shows the signals generated when the dial 130 is operated.
That is, the encode board 134 and the brush unit 1
This shows an example of a circuit configuration for converting a rotational position signal with a 90" phase difference generated by the 35 to a ranging point position signal indicating that a ranging area of 5 points is selected. This almost corresponds to the configuration inside the signal generation circuit 24 shown in Fig. 4. Here, as the dial 130 is rotated one clock clockwise, the distance measurement area on the outer circumferential side is rotated clockwise (for example, from upward distance measurement to rightward measurement). Dial 130 in the following order: distance, downward distance measurement, left distance measurement)
It is assumed that when the center distance measurement is reversed, a signal indicating that the center distance measurement is selected is generated.

When the dial 130 is rotated to the right, the circuit 151 outputs a signal dir indicating the right rotation direction and a number of clock signals CL corresponding to the number of clicks, and the counter 154 outputs the number of clock signals CLK. is counted and this value is output to the ROM 158. The ROM 158 that receives this data outputs a 3-bit signal indicating which of the upper, lower, left, and right distance measuring areas has been selected based on data on the "rotation direction and clock number" held in advance. When the dial 130 is rotated in the opposite direction, the circuit 151 outputs a signal dir indicating the left rotation direction and a 1-clock signal C. Along with this, the output of the exclusive OR gate 156 to which the signal dir indicating the opposite rotation direction and the signal indicating the previous rotation direction from the flip-flop 155 is inverted to high level, and this high level signal is The counter 154 input to the terminal does not accept the 1-clock signal input at this time, so the previous count value remains held. Furthermore, as the output of the exclusive OR gate 156 becomes pi level, the output of the flip-flop 157 also becomes high level for one pulse, that is, a signal indicating that rotation in the opposite direction has been performed during this period is output, and the ROM 158 receiving this signal It outputs a 3-bit signal indicating that the central ranging area has been selected, that is, the aforementioned "1" O.

FIG. 9 is a diagram showing an example of display on the finder. The finder 60 is configured to be able to display positions corresponding to the distance measurement areas 161 to 165.

First, the basic configuration of a display element that performs this display will be explained using FIG. 10. In FIG. 10, 200 is a display element that displays inside and outside a predetermined depth of each distance measurement area 161 to 165 in the finder 60, and 210 is a variable refractive index material, such as liquid crystal. 220 is a relief-type diffraction grating (member) with a grating frame period P made of a material transparent to the wavelength λ used, 230 is a transparent electrode, 240 is a transparent substrate made of a transparent optical member, and 250 has arbitrary polarization characteristics. Incident light 261 and 262 are respectively incident light 2
50, which are mutually orthogonal polarization components, 261 is a polarization component perpendicular to the plane of the paper, and 262 is a polarization component parallel to the plane of the paper.

This display element 200 has transparent electrodes 230 formed on opposing surfaces of a pair of transparent substrates 240.
A relief-type diffraction grating 220 made of a transparent material is provided on one transparent substrate 230, and the grooves (concavities) of the diffraction grating 220 are filled with a variable refractive index material 210. Then, by applying an electric field through the transparent electrode 230, the refractive index of the variable refractive index material 210 is changed.

Next, the principle of operation of the display element 200 will be explained, taking as an example a case where liquid crystal is used as the variable refractive index material 210.

In FIG. 10, in a so-called static state where no electric field is applied, the liquid crystal 210 is aligned in the groove direction of the diffraction grating 220.
That is, it is assumed that they are oriented in a direction perpendicular to the plane of the paper and maintain a homogeneous orientation state.

Incident light 250 that enters the display element 200 in this static state
Of the polarized light components 261 and 262, the polarized light component 262, which is a component perpendicular to the alignment direction of the liquid crystal 210, senses the ordinary refractive index no of the liquid crystal 210, and the polarized light component 261, which is a component parallel to the alignment direction of the liquid crystal 210, senses the ordinary refractive index no of the liquid crystal 210. Abnormal refractive index ne of liquid crystal 210
I feel it. Here, the refractive index n of the material forming the diffraction grating 220
g, the wavelength of the incident light 250 is λ, and the thickness of the diffraction grating 220 is T. When the diffraction grating 220 is rectangular, the incident light 2
Zero-order transmission diffraction efficiency η for each of the 50 polarization components 261.261. is approximately expressed by the following equation.

77(, = 172 (1+cos(2π・Δn−
T/λ)) However, Δn is the refractive index difference between the refractive index ng of the diffraction grating 220 and the refractive index no or ne of the liquid crystal 210, and for the polarization component 262 of the incident light 250, Δn=1n
o ngl, and for the polarization component 261, Δn=
I ne -ng I.

Therefore, from the above formula, when Δn==o, that is, ne=
The diffraction efficiency η of zero-order transmission diffraction when ng.

becomes 77o=1. Also, ΔnT=(m+1/2)λ, (
m=0.1, 2.3. ...), the diffraction efficiency η0 becomes ηo=Q.

Next, when an electric field is applied to the liquid crystal 210 via the transparent electrode 230, the alignment direction (optical axis direction) of the liquid crystal 210 gradually changes. At this time, the polarized light component 262 in the incident light 250 always senses the ordinary refractive index nQ of the liquid crystal 210 regardless of the application of the electric field. On the other hand, the polarization component 261 senses a composite refractive index nx obtained by combining the extraordinary refractive index ne and the ordinary refractive index n0 of the liquid crystal 210 at a predetermined ratio in accordance with the amount of applied electric field. Here, the composite refractive index nx changes as the alignment direction of the liquid crystal 210 changes. When the amount of applied electric field is further increased, the liquid crystal 210 is aligned perpendicularly to the transparent substrate 240 (transparent electrode 230) and becomes a homeotropic alignment state, and the incident light 210
50 polarized light components 260 and 261 both sense the ordinary refractive index n0 of the liquid crystal 210 and are saturated. Even in this state, the incident light 250 is modulated according to the above equation.

FIG. 11(a) is an optical layout diagram of a single-lens reflex camera such as the display element 200, and FIG. 11(b) is a more detailed sectional view of the display element 200. In FIG. 11(a), 201 is a photographing lens, 2°2 is a quick return mirror, 203 is a focus plate, 204 is a condenser lens,
205 is a pentaprism, 206 is an eyepiece, 207
is a display drive circuit that drives the display element 200. Note that the distance measuring optical system is not shown in this figure. Figure 11(b)
, 221, 222 are diffraction gratings, 231, 232
．． 233, 234 are transparent electrodes, 241, 242, 243
is a transparent substrate. Note that the display element 200 shown in FIG. 11 was adopted in this example, and the display element 200 shown in FIG. Although they are different, the same reference numerals are given for the sake of simplicity and the explanation will be continued below.

The light transmitted through the photographic lens 201 is guided to the finder optical system via the quick return mirror 202, and then the focus plate 2
The image is formed on the focal plane of 03.

The light emitted from the focusing plate 203 is the F of the photographing lens 201.
It is diffused with an intensity according to the value and the diffusion characteristics of the matte surface, and a part of it is diffused by the condenser lens 204 and the pentaprism 205.
, reaches the human eye via the eyepiece 206. Here, the light that actually enters the eye is limited by the entrance pupil of the optical system consisting of the condenser lens 204, pentaprism 205, eyepiece 206, and eye.
This is light that is emitted within a normal angular range of 3 degrees around the optical axis on 3.

The display element 200 is arranged near the focusing plane of the focus plate 203, and the display/non-display state and display position (range-finding area position) are controlled by a display drive circuit 207. In the non-display state, the display element 200 is regarded as a transparent substrate with a -like refractive index, and the subject image formed on the focal plane is transmitted to the eye via the condenser lens 204, pentaprism 205, and eyepiece lens 206 without being modulated. The image is directly formed on the retina. In the display state, a portion of the light incident on the display element 200 is diffracted by a diffraction grating that is a display pattern. Since the component with a large diffraction angle of the diffracted light is blown out of the field of view of the eye, a portion of the subject light is visually recognized as being attenuated, and the display overlaps with the subject image.

Here, the display element 200 is composed of two display elements that display different colors, and each operating principle is based on the first
This is as explained in Figure 0. In FIG. 11(b),
The grating lines of the diffraction grating 221 and the diffraction grating 222 are orthogonal, and in the figure, T1 indicates the depth of the grooves of the diffraction grating 221, and T2 indicates the depth of the grooves of the diffraction grating 222. Now, the refractive index ng of the diffraction grating 221 and 222 is 1.53, and the liquid crystal 210
refractive index ne = 1.78 (n,) = 1.53)
, assuming that the groove depth TI of the diffraction grating 221 is 1.5 μm and the groove depth TI of the diffraction grating 222 is 2.5 μm, from the above equation, the incident light 250 with a polarization component 261 perpendicular to the plane of the paper is
is the liquid crystal 210 (ne = 1.78) and the diffraction grating 221
Modulated by the refractive index difference between (ng = 1.53),
The transmitted light has a blue color, and the incident light 250 having a polarization component 262 parallel to the plane of the paper is modulated by the difference in refractive index between the liquid crystal (not shown) and the diffraction grating 222, and the transmitted light has a red color. Since the incident light 250 is generally non-polarized, selecting two display layers by the display drive circuit 207 enables display of different colors.

In this embodiment, for the selected ranging area, the ranging area is measured, automatic ranging is performed using the obtained ranging information, and the corresponding ranging area is determined based on the ranging information in that ranging area. The display drive circuit 207 selectively displays the inside/outside depth of the position in blue or red.

Next, display drive control based on the depth-priority AP result will be described using FIG. 12. Note that this FIG. 12 corresponds to the circuit configuration of the main part in the display drive circuit 207 shown in FIG. 11.

The address signal (output from ROM 158 in FIG. 8) indicating the distance measurement area position selected by the photographer is sent to the latch circuit 305,
309, and the corresponding signal line is selected from among the signal lines 300 to 304 and 310 to 314. That is, for example, when the center distance measurement area is selected (when the distance measurement area 161 shown in FIG. 9 is selected), the signal lines 300 and 310 are selected.

When the center ranging area is selected and no instruction to start ranging is given, the signal line C is at a low level, and the latch circuits 305 and 309 are sent via signal lines b and d. Input focused (within depth) signals and out-of-focus (outside depth) signals are not latched. Also, the signal line C
Since is at a low level, in this case, the AND gate is 30
7 opens the gate, and the oscillation circuit 306 output is the OR gate 3.
It is input to the latch circuit 305 via 08.

As a result, the output (blinking signal) of the oscillation circuit 306 is directly outputted from the latch circuit 305 via the signal line 300, and the operation described in FIG. 11 is performed in the display element (not shown), as shown in FIG. The distance measurement area 161 portion shown in is blinking in blue. This is recognized by the photographer as the display of the currently selected distance measurement area pointing point.

When an instruction to start distance measurement is given, the signal line C becomes high level, so the latch circuits 305 and 309 receive the in-focus (in-depth) signal and the out-of-focus (in-depth) signal manually input via the signal lines b and d. (outside depth) signal will be latched. Suppose that the distance measurement of the central distance measurement area 161 is now performed, and as a result, a high-level focus signal is input via the signal line b, the latch circuit 305 receives a high-level signal via the signal line 300. Output. As a result, the distance measuring area 161 shown in FIG. 9 lights up in blue. This is recognized by the photographer as a display indicating that the currently selected distance measurement area is within the in-focus area. - When a high-level out-of-focus signal is input via the force signal line d, the latch circuit 309 outputs a pi-level signal via the signal line 310. As a result, the distance measuring area 161 shown in FIG. 9 lights up in red. This is recognized by the photographer as an indication that the currently selected distance measurement area is not within the in-focus area.

Furthermore, the latch circuits 305 and 309 are reset by a reset signal generated when the power is turned on or immediately before a new distance measurement is started.

As described above, by both displaying the distance measurement results for each point and the corresponding display, the system is easier to use due to the interactive format.

FIG. 13 is a block diagram for realizing multi-point depth priority control.

This is to set the lens position and aperture so that all the ranges are within the depth of field based on the distance measurement information of each of the ranges that are specified one after another, and even the minimum aperture of the lens is within the depth of field. If the object does not enter the range, a message indicating that the range is outside the depth is displayed and the object is ignored. The photographer can sequentially give instructions starting from important subject points (range area).
Depth-prioritized AP and AE can be performed while checking whether the depth is within the range.

In FIG. 13, 351 is a counter that counts the number of distance measurement area selections, 352 is an AND gate, 353 is a memory circuit that holds the lowest defocus value of the distance measurement results that have been performed several times, and 354 is a memory circuit that stores the highest value. Memory circuit for holding, 35
5 to 358 are diodes for obtaining the minimum and maximum distance measurement results, 359.360 is a differential amplifier circuit, 361 is a differential amplifier circuit for calculating the required depth, 362 is an arithmetic circuit, and 363 is a differential amplifier circuit. A comparison circuit, 364, an aperture information generation circuit that generates minimum aperture information (maximum aperture value) of the lens, 365
is a latch circuit, 366 is an inverter, 367 is a buffer, 368 is a display drive unit that performs depth display (red display),
Reference numeral 369 denotes a display drive section that performs depth circle display (blue display), and these are arranged, for example, in the display drive circuit 207 in FIG. 11. Further, hp is a signal line.

In the above configuration, when the first distance measurement is instructed, the count value of the counter 351 is zero, so the distance measurement signal input via the signal line k (this includes the selected distance measurement area, the error of the sub mirror, etc.) ) is the result value obtained in the state in which
Output to the F drive system. Also, at this time, as mentioned above, since the count value of the counter 351 is zero, the differential amplifier circuit 36
1 is inactive. Therefore, the required depth is zero, and the output of the comparison circuit 363 (signal line I2) which compares the required depth information with the information from the aperture information generation circuit 364
) is at a high level. As the signal line β goes high in this way, the latch circuit 365 stores the required depth and outputs the aperture instruction value to the photometry system via the signal line m. At the same time, an AF instruction is issued via the signal line q. Furthermore, since the display system is within the depth, buffer 3
A high level is applied to the display drive section 369 through the signal line 67 and the signal line 0 (depending on the timing of generation of the distance measurement instruction signal), and a blue display is made in the area corresponding to the distance measurement area at this time. Furthermore, the count value of the counter 351 is advanced by "+1" due to the high level of the signal line β.

If it is outside the depth, the signal line °C becomes a low level, so a high level is given to the display drive unit 368 via the inverter 366 and the signal line n,
At this time, the area corresponding to the distance measurement area is displayed in red.

Then, AF operation etc. are not performed.

Next, the nth distance measurement instruction will be described.

When the nth distance measurement instruction is given, the arithmetic circuit 362 performs a new,
The deviation between the new and old average values of the old multiple points is (deviation D/(n+1)
) and outputs the result to the AP drive system via the signal line p. As mentioned above, the diodes 355 to 358 are for obtaining the lowest and highest values, and from these, the lowest defocus signal in the distance measurement up to this time at the current lens position is transmitted via the signal line h. Similarly, the highest defocus signal is sent to the differential amplifier circuit 35 via the signal line j.
Sent to 9,360. The differential amplifier circuits 359 and 360 that receive this signal take into consideration this signal and the defocus signal at the current distance measurement position, and generate near and far side defocus signals from the average defocus position up to this time. is generated. Then, the differential amplifier circuit 361 calculates these defocus widths, that is, the required depths, and the comparison circuit 363 compares them with information (minimum aperture diameter information) from the aperture information generation circuit 364, as described above. As a result, if the defocus width does not fall within the depth of field even with the minimum aperture diameter,
In other words, when the output of the comparator circuit 363 becomes a low level, a red display indicating outside the depth is displayed in the selected distance measurement area at that time by the action of the drive unit 368 as described above, and in this case, the low level By inputting this signal, the latch circuit 365 does not output update data for a requested aperture value that cannot be narrowed down. Furthermore, as described above, AF driving etc. are not performed, and the highest and lowest defocus signals are not updated by the AND gate 352.

On the other hand, when entering the depth, the signal line β goes to a high level, and as mentioned above, the aperture value is updated, the blue display indicating that the depth is within, the focusing operation to the averaging point, etc. are performed, and the AND gate 352 is also activated. Through the differential amplifier circuit 359.36
The storage circuits 353 and 354 hold the near side and far side defocus signals at the new lens position output to zero.

Next, FIG. 14 shows a circuit configuration that enables automatic distance measurement position selection.

Here, for example, distance measurement is started from the center distance measurement area, and if the reliability of the resulting distance measurement signal is low (such as when the subject contrast is low), the distance measurement position is changed one after another to ensure reliable measurement. It is designed so that distance can be achieved.

In other words, for example, distance measurement is first performed in the central range measurement area,
When the result (distance measurement signal) is input to the comparison circuit 405,
Here, the reference voltage (
This is compared with a threshold level (which disables distance measurement results with low contrast), and if the reliability of the distance measurement results at this time is low, the output of the comparison circuit 405 is inverted to low level. As a result, a one-pulse distance measurement completion signal is input to the quinary counter 401 via the AND gate 408, and the count value here advances. The ROM 400 which receives the count value from the counter 401 is the ROM shown in FIG.
158, for example, the counter 40
Each time the count value in 1 advances by one, a signal is generated to change the ranging position in the order of center ranging - upper ranging - right ranging - lower ranging → left ranging. As described above, when the count value of the counter 401 advances by one, a signal is generated to cause the next upward distance measurement to be performed. Similar operations are repeated in sequence until a highly reliable ranging signal is obtained.

According to this embodiment, the TTL ranging system using the secondary mirror 4, which has been difficult to maintain accuracy in the past, can be replaced with
It has two reflecting surfaces (reflecting parts 48 to 4e) and is combined with a variable vertex angle prism 6 for controllable variable optical path selection.
In other words, the fixed variable apex angle prism 6 is used to ensure accuracy for items that require quick return operation, such as the secondary mirror 4.
This enables multi-point distance measurement by controlling the angle of the camera. This eliminates the need for preparations such as prefocusing before framing, unlike in the past, allowing the user to concentrate on framing, resulting in ease of use. Also, distance measurement for subjects other than the center according to the user's intention,
It becomes possible to interactively perform automatic evaluation distance measurement and evaluation distance measurement according to the user's intention. Furthermore, the combination of multi-point distance measurement and finder display allows for easy-to-use multi-point distance measurement operations and multi-point depth-priority AF. That is, it is possible to prioritize the depth of multiple points while checking the distance measurement position by selecting the distance measurement position and displaying the inside/outside depth.

Furthermore, by changing the angle of the variable apex angle prism 6, which enables angle control using a simple mechanism, the distance measuring light flux is guided to the distance measuring sensor 7, so that only one distance measuring sensor is required. Multi-point distance measurement can be performed without increasing costs. Further, the light source 9 and the projection lens 10 are connected to each other, and the light is projected onto the reflecting member 8 that is integrally provided on the sub mirror 4, and the position on the distance measuring sensor 7 from the reflecting member 8 is observed. Since the current position of the sub-mirror 4 can be checked, the position error and amount of error of the sub-mirror 4 can be known, making maintenance easy. Furthermore, the variable apex angle prism 6
Since the sub mirror 4 is automatically finely adjusted, the sub mirror 4 is constantly calibrated, and there is no need for maintenance associated with this.

Furthermore, if the distance measurement result at a certain distance measurement position is unreliable, distance measurement is performed at other distance measurement positions one after another until a highly reliable distance measurement result is obtained. Because of this configuration, even in the case of a pattern with low contrast, it is possible to automatically search for a high contrast part over a wide range.

(Correspondence between the invention and the embodiments) In this embodiment, the variable apex angle prism 6, the signal generation circuit 24. ANDGATE 40-42. ROM46, drive unit 5
3.54 is the deflecting means of the present invention, the reflecting member 8 is the optical signal generating means, the distance measuring sensor 7, the distance measuring circuit 21 is the position detecting means, the peak position detecting circuit 30 to the latch circuit 37, and the ROM 46 are Each corresponds to a fine adjustment means. Further, the quick return mirror 1 corresponds to the main mirror.

(Modified example) In this embodiment, the variable apex angle prism 6 is used as a member for selecting the distance measuring optical path, but the optical path selection may be performed using a lens that also serves as a condenser lens for AF. FIG. 15 shows this example.

In the figure, reference numeral 410 denotes a hemispherical lens, which in this case functions as a simple condenser lens having a lens effect regarding the light beam 411. However, when the sphere is tilted with the center of the sphere as the center (center of the flat surface) as shown in 410', the prism effect on the light beam 411' is
14, and works as the same condenser lens. In this way, by rotating the lens, it functions as an optical path selection means while having the function of a condenser lens.

Similarly, it may be done by moving the lens,
When the AF system includes a reflection system, the light beam may be selected by tilting the reflection surface.

(Effects of the Invention) As described above, according to the present invention, the secondary mirror is configured with a plurality of reflecting parts that divide the photographing screen into a plurality of distance measurement fields, and each of the plurality of reflecting parts reflects A deflecting means is provided for deflecting a distance measuring light beam from the part so as to be incident on a predetermined position on the distance measuring sensor, and the distance measuring field of view within the photographing screen is selected by deflection control by the deflecting means. Therefore, multi-point distance measurement can be performed with a simple configuration.

Further, an optical signal generating means configured integrally with the sub mirror and generating an optical signal, and a position detecting means detecting the current position of the sub mirror from the optical signal from the optical signal generating means are provided. , further comprising fine adjustment means for checking the current position of the secondary mirror, comparing the position information from the position detection means with reference position information, and finely adjusting the deflection means based on the error information, Since the current position of the secondary mirror is confirmed and the positional error of the secondary mirror from the reference position is calibrated by fine deflection adjustment of the deflection means, it is possible to check whether the position of the secondary mirror is appropriate. Furthermore, it is possible to automatically calibrate the position error.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing an embodiment of the present invention, Fig. 2 is a view of the distance measuring optical system shown in Fig. 1 seen from above, and Fig. 3 is a view from the front, side, and bottom of the secondary mirror shown in Fig. 1. Fig. 4 is a block diagram for controlling the variable apex angle prism associated with distance measurement area selection, Fig. 5 is a diagram explaining another example of the position error of the sub mirror, and Fig. 6 is its position. A circuit diagram of the main parts for correcting errors; FIG. 7 is a perspective view showing a dial mechanism for selecting a distance measurement position; FIG. 8 is a circuit diagram for generating a position signal for a selected distance measurement area; FIG. 9 The figure shows the viewfinder display, No. 10.
The figure is a cross-sectional view showing the basic structure of the display element adopted in this example, FIG. 11(a) is an optical layout diagram of a single-lens reflex camera in which the display element is arranged, and FIG. 11(b)
is a cross-sectional view showing the structure of the display element of this example, FIG. 12 is a circuit diagram for display control, FIGS. 13 and 14 are circuit diagrams related to multi-point depth priority, and FIG. 15 is an optical path selection member. It is a figure showing other examples. 1...Quick return mirror, 4...
・Secondary mirror, 6...Variable apex angle prism, 7...
...Photometry sensor, 8...Reflection member, 9...
...Light source, 10... Light projection lens, 21...
... Distance measurement circuit, 24 ... Signal generation circuit, 3
0...Peak position detection circuit, 31...
Central position information generation circuit, 32... Counter, 3
3... Comparison circuit, 34... Light amount detection circuit, 35... Peak detection circuit, 36...
・Sawtooth wave generation circuit, 37...Latch circuit, 40~
42...and gate, 46...RO
M, 53.54... Drive unit. Figure 2 Figure 3 Figure 4 Figure 7

Claims (3)

[Claims] (1) Measurement for single-lens reflex cameras equipped with a sub-mirror that is movable in and out of the photographing optical path together with the main mirror, and that guides the light passing through the photographing lens transmitted through the main mirror to the distance-measuring sensor as a distance-measuring light beam during distance measurement. In the distance measuring device, the sub-mirror is composed of a plurality of reflecting sections that divide the photographing screen into a plurality of distance measuring fields, and the distance measuring light flux from each of the plurality of reflecting sections is directed onto the distance measuring sensor. 1. A distance measuring device for a single-lens reflex camera, characterized in that a deflection means is provided for deflecting the light so that the light is incident on a predetermined position. (2) Optical signal generating means configured integrally with the sub-mirror and generating an optical signal, and position detecting means detecting the current position of the sub-mirror from the optical signal from the optical signal generating means. 2. A distance measuring device for a single-lens reflex camera according to claim 1. (3) an optical signal generating means that is configured integrally with the submirror and generates an optical signal; a position detecting means that detects the current position of the submirror from the optical signal from the optical signal generating means; and the position detecting means. 2. The distance measuring device for a single-lens reflex camera according to claim 1, further comprising fine adjustment means for comparing the position information from the means with reference position information and finely adjusting the deflection means based on the error information. .