JPH02158705A - Multipoint range finding camera - Google Patents

Abstract

PURPOSE:To shorten a release time lag while preventing a middle misfocusing phenomenon by measuring all of range finding positions with a 2nd range finding mode which is low in distance resolving power but is short in range finding time and subjecting the range finding position selected in accordance with the results of this measurement to range finding with a 1st range finding mode which is long in the range finding time but is high in the distance resolving power. CONSTITUTION:A range finding means 14 has the 1st range finding mode which is long in the range finding time but is high in the distance resolving power and the 2nd range finding mode which is short in the range finding time but is low in the distance resolving power in all the range finding positions. A control means 7 measures all of the range finding positions by the 2nd range finding mode, selects the range finding position in accordance with the results thereof and subjects the selected range finding position to the range finding by the 1st range finding mode at the time of making range finding by the range finding means 14. The release time lag is shortened in this way while the multipoint range finding is executed in order to prevent the middle misfocusing phenomenon.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a multi-point distance measuring camera, more specifically, a multi-point distance measuring camera, which projects infrared light from a plurality of infrared light emitting diodes toward a subject, and captures the reflected light from the subject. The present invention relates to a so-called active type multi-point distance measuring camera that automatically measures the distance to a subject by receiving light and drives the lens to a focused point.

[Conventional technology] Conventionally, automatic focusing systems for cameras, etc. can be broadly divided into two types.
Two methods have been adopted. One is a passive method that performs distance measurement based on the brightness distribution information of the subject, and the other is a method that projects a beam such as infrared light or ultrasonic waves toward the subject and measures the distance based on the reflected signal. This is an active method that performs 4Ij distance.

Among these, infrared light is projected toward the object through the projecting lens, and the reflected light from the object is sent to the semiconductor device detection device through the receiving lens, which is provided at a certain distance from the projecting lens, that is, the baseline length. An autofocus (hereinafter abbreviated as AF) device using the so-called infrared floodlight active triangulation method, which receives light and measures the distance to the subject based on the incident position, can be realized with a simple configuration, so it is used in many products. has been praised by Jiewa.

However, when taking pictures using this method, if the main subject does not exist in the direction of the light projection, the AF will focus on other subjects or the background, resulting in an out-of-focus picture of the main subject. (Hereinafter, this is referred to as "Nakabuki").

Therefore, depending on the composition, you may need to place the subject in the rangefinder frame that indicates the direction of the infrared light emitted in the viewfinder, measure the distance, and then reset the framing to take the picture, which is called focus lock. It required a named operation.

Therefore, Δ) A wide-field AF that uses multiple I-pressure projection signals to measure multiple 7j111 distance positions in the finder
A photographic technique called 1 or multi-point ranging was proposed,
This is an attempt to make complicated operations such as focus lock unnecessary.

[Problems to be Solved by the Invention] However, in the case of an AF camera that incorporates an AF weight based on the infrared floodlight active triangular 11111 distance method using such multi-point distance measurement technology, it takes a long time to perform one distance measurement. Because distance measurement time is always limited to a certain distance, it is necessary to
The more distance measurement points are added for each pj distance position, the longer the time required for distance measurement becomes. In other words, since the camera release time lag becomes longer, there is a risk that delicate photo opportunities may be missed.

SUMMARY OF THE INVENTION Therefore, it is an object of the present invention to solve the above-mentioned problems and to provide a multi-point distance measuring camera with a short release time lag while performing multi-point distance measuring in order to prevent the hollow phenomenon.

[Means and effects for solving the problem] The multi-point distance measuring camera according to the present invention is a multi-point ΔP 1-range camera that measures the distance of a subject at each of a plurality of 4-1 range devices within the photographic image frame. At each of the above positions, at least two modes are selected: 1llll + a first ranging mode that has a long ranging time but a high range resolution, and a second ranging mode that has a short ranging time but a low range resolution.
A distance measuring means for a of two motes, and an A by this distance measuring means.
For l11 distance, all of the above plurality of 1ltll distance positions are measured using the second distance measurement mode, a distance measurement position is selected based on this result, and then this selected distance measurement position is used in the above-mentioned first distance measurement mode. The present invention is characterized by comprising a control means for performing distance measurement in ApI distance mode.

[Examples] First, before describing specific examples of the present invention, an overview of the multi-point distance measuring camera of the present invention, its distance measuring mode and distance measuring time will be explained using Figs. 2 to 4. explain.

FIG. 2 is a block system diagram showing an overview of the present invention.

In the figure, the control means 7 with a built-in CPU accepts the human power of the release switch 13 and controls all distances, 71F1.
Controls camera sequences such as light, exposure, and film winding/rewinding. When the All distance means 14 receives the distance measurement start signal S1 and the distance measurement point setting signal S2 from the CPU built in the control means 7, the All distance means 14 receives the distance measurement start signal S1 and the distance measurement point setting signal S2.
Start the distance measuring point 11111 set in step 2,
1 (The pl distance result is returned to the CPU as Apl distance data S4. Then, the CPU determines the amount of extension of the focusing lens based on this distance measurement data, and drives the motor 11 via the driver 10 to achieve focusing. Drive the focusing lens to the focal point.

Another feature of the present invention is a distance measurement mode switching signal S3, which allows the distance measurement means 14 to switch the distance measurement mode described later.

Figure 3 is a configuration diagram of the finder field frame, and Figure 4 (A)
, (B) shows each distance measurement point in Fig. 3 above as Al
11 is a diagram showing distance measurement time required for 11 distances. FIG. As shown in FIG. 3, for the screen within the finder field frame 56c,
The distance measurement frames 56d, 56e, and 56f measure the distance measurement point A
When calculating the tPj distance of each point B and C, the distance measurement point) B,
In the case of point C, the focus is on the background 56a, so the distance measurement result is shown at infinity, whereas in the case of point A, the main subject 5
Since the focus is on 6b, it indicates API distance measurement at a shorter distance, and as a result, the main subject 5
It can be considered that 6b exists.

In this case, in order to find out where the main subject is among distance measurement points A, B, and C, All+Distance (hereinafter referred to as the first distance measurement mode) is If this is done, the 4111 distance time will become longer and the release time lag will also become longer, which is extremely wasteful.

That is, if the distance measurement time required for one-point distance measurement in the first distance measurement mode is tl, the total distance measurement time required for three-point distance measurement described above, that is, the release time lag [3] is shown in FIG. 4(A). As shown, t3-3xt.

It will take a long time.

However, the 17th part that determines the amount of lens extension
Even if the distance measurement accuracy is not as high as that achieved by the IllI distance mote, it is possible to roughly detect which of the distance measurement points A, B, and C is the closest.
API distance open time required for point distance measurement 1 A depending on side distance mode
ll+distance The second time t2 is sufficiently short compared to the distance time t1.
If the Jl distance mode is provided, the total distance measurement time, that is, the release time lag, can be shortened as shown in the comparison in FIG. 4(A) (I3).

In other words, if the distance measurement time required for one-point distance measurement in the 21st (11th distance mode) is tl, then as mentioned above, the second measurement determines which of the distance measurement points A, B, and C is the closest. The total ranging time t4 when performing API ranging in range mode and ill ranging only to the closest all range points in the first side ranging mode is t - 3Xt2 + t1. Therefore, the total ranging time ta , t4 <
In order for the relationship t3 to hold, 1lllll distance points or 3
In the case of a point, it can be seen that such an apr distance mode is valid if tl<Ttl.

For example, the distance measurement time 11 required for one point 71I11 distance in the first distance measurement mode is 60 m5ec, and the distance measurement time t required for one point all distance in the second distance measurement mode.
2 or 20m5ec, the total i'lPI distance time t3.
t4 are t-180m5ec and t4-120, respectively.
mscc, thereby reducing the release time lag of 40m5ec.

In this case, the greater the number of 11 distance points, the greater the effect of the time lag countermeasure that reduces this release time lag. In other words, if the difference between 'l1l11 distance time [1 and tl] required for one-point distance measurement in each distance measurement mode is Δt, the release time rough angle/I measure effect is nt - (nt ,, +tl) -n (tl-tl)+tl -n"Δ1-11.

By the way, in the second distance measurement mode, each distance point is set to 1 point 7.
] It is possible that the distance measurement data obtained when measuring 111 distances are all the same. In such a case, it is necessary to distance each distance measurement point 7111 times in the first side distance mode with high distance resolution.
The time lag will only get longer.

Therefore, in such a case, the present invention uses the conventional empirical rule,
In other words, we introduce a statistical result that shows that there is a probability of 80% or more that the main subject is in the center of the screen, and measure only one point in the center using the first distance measurement mode, thereby increasing the release time lag. It is prevented.

Next, specific examples of the present invention will be described. First, a camera equipped with an active triangular i'1ll distance method AF that performs 1 point full+range, which is the basis of multi-point 7ip+range, will be described.

FIG. 1 is a block diagram showing the configuration of the main parts of an automatic exposure camera according to the present invention, in which light emitted by an IRED (infrared light emitting diode) 1 is focused by a light projection lens 2 and directed toward a subject 3. The reflected light is transmitted to a well-known position detection device (hereinafter referred to as PSD) made of a semiconductor by a light receiving lens 4.
(abbreviated as ) 5. In this PSD 5, photocurrents I and I2 are divided according to the imaging position, and the divided photocurrents I and I2 are supplied to Al1111C6. This AF IC 6 pulse-drives the control transistor port IREDI for controlling the IRED, and also based on the photocurrent II, 12 from the PSD 5.
The Ap+ distance data and the reflected light intensity data are supplied to the CPU or the built-in control means 7.

On the other hand, exposure control (which converts the brightness of the subject into an electrical signal)
The light receiving cable 8 for EE (hereinafter abbreviated as EE) is the IC 9 for EE.
In combination with this, proper exposure is controlled. The control means 7 also controls the sequence of the entire camera, and performs calculations such as the opening time of the shutter and driving the focus adjustment lens. The output of the control means 7 drives a motor 11 which is a power source for driving the shutter, film winding, and lens feeding by the driver 1°.

Here, the operating principle of the infrared light active triangulation method for measuring the object distance using the PSD 5 will be described.

When the optical axis of the light-receiving lens 4 is aligned with the center line of the PSD 5 and this is set as the origin, the reflected light incident position is X, and the distance between the principal points of the light-emitting lens 2 and the light-receiving lens 4, that is, the baseline length is S, and if the focal length of the light receiving lens 4 is f, then the distance between subjects i
4g is (1-s・f/x...old...(1
) is given by

Photocurrent generated in PSD5 1. , 12 are both proportional to the incident light intensity, but the photocurrent ratio 1 /I does not depend on the incident light intensity and is determined only by the incident light position X. P.S.D.
Let the total length of 5 be t. Substituting equation (1) into the above equation yields (2). Therefore, if the photocurrent 1 t / I 2 of PSD5 is found, the object distance Ω is uniquely determined. That will happen.

In Fig. 1 above, in order to simplify the explanation of the distance measurement principle of the active triangulation method, a configuration is used that performs simple one-point distance measurement, but when this is applied to three-point distance measurement, Δ- 1
The configuration of the optical system etc. of the distance means 14 is shown in FIG.

In FIG. 5, three IREDs 41a and 41b.

3 PSDs 44a, 44b for 41c.

44c (1st eye, 31 hard I RED41
a.

Infrared beams 47a for distance measurement from 41b and 41C.

The beams 47b and 47c are directed toward the subject by the projecting lens 42, and each beam reflected by the subject is made to enter the corresponding PSD among the three PSDs 44a, 44b, and 44c by the light receiving lens 43. In addition, in this FIG. 5, the light emitting lens 42 and the light receiving lens 43 are arranged horizontally to make it easier to understand the overall (1η configuration), but in reality, the horizontal direction shown in FIG. By changing the arrangement to a vertical arrangement, that is, the light emitting lens 42 and the light receiving lens 43
are arranged vertically, and three IREDs 41a, 41b, 41
The infrared beam from c is transmitted to the viewfinder field frame 56c shown in FIG.

56f.

As a specific configuration example of the optical system in this A11l distance means 14, the infrared beam 47 from the central IRED 41b is
The angle α formed by the infrared beams 47a and 47c from the left and right IREDs 41a and 41c with respect to
, if the focal length of the projection lens 42 is 'al, then tan a-g1/f,! is designed to satisfy.

Also, the distance between the PSDs 44a, 44b, and 44c is set to g2.
If the focal length of the light receiving lens 43 is fa2, then fal”
When set to 'a2, it is set to gl-g2.

The reason why the PSD is divided into three is to minimize the influence of incident light from other directions when the distance is from -point 7I11, thereby improving S/H.

FIG. 6 is a specific electrical circuit diagram of the AF IC 6 to which the three IREDs and three PSDs are connected.

In FIG. 6, the photocurrents 1, , I2 from the PSD 44a
are the voltage signals V at the pre-stage amplifiers 52a and 53a, respectively.
and V2, that is, the voltage corresponding to the position of the incident light to the PSD 44a, and then supplied to the channel changeover switches 54a and 55a, respectively.

This channel changeover switch 54a.

55a is controlled by a channel switching signal from a channel switching circuit 60, which will be described later, via a switching circuit 67a.

The other PSD44b and PSD44C are also configured in the same manner as the above circuit. In Figure 6, PSD
The circuit related to PSD44b has a code ending in b.
Circuits related to c are shown with the suffix C.

Further, each circuit regarding these three PSDs 44a, 44b, and 44c is a switching circuit 67a.

A switching signal from the decoder 68 is sent to 67b and 67c to selectively control switching. Decoder 68 has three IR
The oscillator 65 sends a drive pulse signal a of a constant frequency to the driver 69 for causing the EDs 41a, 41b, and 41c to emit pulsed light, and also in response to a switching command from the control means 7 (see FIG. 1). , dl
The distance measurement points are set in accordance with the distance point setting signal S2 (see FIG. 2), and the switching circuits 67a, 67b, and 67c control the switching of the three PSD circuits. In other words, A at three points A11l distance
The F sequence is performed on a time-sharing basis to perform Jllll distance calculations using a common IC, and the IRED41
When a is emitted, only the output of PSD44a is processed, and I
When the RED 4 lb emits light, only the output of the PSD 44b is processed, and when the IRED 41° C. emits light, only the output of the PSD 44c is processed.

Regarding each circuit of the three PSDs 44a, 44b, and 44c, one of the voltage signals V t and V 2 is applied to a band pass filter (hereinafter abbreviated as BPF) in a time-division manner according to the logic level of the channel switching signal. 56. The BPF 56 selectively passes only the same frequency component as the frequency of the drive pulse signal emitted from the oscillator 65, and removes background light from the photocurrent of each PSD and photoelectrically converts only the effective reflected light from the subject. pass through. The integration switch 57 converts the filter output signal of the BPF 56 into the signal e from the integration timing pulse circuit 70.
The signal is supplied to the integrator 58 in synchronization with . The integral output V1 of the integrator 58 is input to a comparator 59 and compared with the base 4 voltage Vrer, and the output signals C of the five comparators are supplied to a channel switching circuit 60 composed of a D-type flip-flop or the like. The channel switching signal d output from the circuit 60 is sent to the switching circuits 67a, 67b, and 67c, so that the two channel switching switches in each PSD circuit, for example, the channel switching switch 54a for the PSD 44a circuit. , 55a are controlled. The channel switching signal d from the channel switching circuit 60 is also supplied to an AND gate 61 that controls the input pulse of the positive integration counter 62 and an integration timing pulse circuit 70, respectively. The positive integral number counter 62 doubles as a shift register, and the channel switching signal d from the channel switching circuit 60 is "
This is to count the number of synchronous integrations during positive integration when the gate 61 is open and the channel selector switches 54a, 54b, and 54c are on.After the AF operation is completed, the first The distance measurement data is transferred to the CPU of the control means 7 shown in the figure.Furthermore, the total integration number counter 63 consisting of a preset counter etc.
As will be described later, a termination circuit 6 counts the total number of times of synchronous integration, that is, the timing pulse e from the integral timing pulse circuit 70, and terminates the AF process when the set number of times is reached.
A counting signal is supplied to 4.

The circuit operation of the AF IC 6 shown in FIG. 6 will be briefly described with reference to the timing chart shown in FIG. The AF operation is started when the AF IC 6 receives a ranging start signal S (see FIG. 2) and a basic clock signal from the CPU of the control means 7. Now, if I RED
41 a, PSD44a, TRED
41a starts pulsed light emission, the output voltages V t , V 2 of the front stage amplifiers 52 a and 53 a supplied with a photocurrent of 1.1 from the PSD 44 a that has received the subject light increase.
The voltage waveform V1. The ratio of the peak value of V2 is the above-mentioned 11/
It becomes equal to I2. Further, upon receiving the A1j distance start signal S1, the channel switching circuit 60. Positive integral number counter 6
2 and the total integration number counter 63 are reset. At this time, since the channel 9 switching signal d from the channel switching circuit 60 is "L", the channel switching switch 54
a is off, switch 55a is on, and light 713k
A voltage V2 proportional to l2 is applied to the BPF 56. Here, when the timing pulse e is applied from the integration timing pulse circuit 70 and the integration switch 57 is turned on, the output of the BPF 56 supplies a voltage proportional to the photocurrent I2 to the integrator 58. Therefore, the integral output V1 of the integrator 58 is integrated (inverse integrated) at the positive peak b1 of the filter output signal of the BPF 56. When the integral output V1 falls below the base voltage Vrer, the output of the comparator 59 changes from "L" to "H", and the channel switching signal d from the channel switching circuit 60 changes to "L'" in synchronization with the timing pulse et. Since it becomes "H", the channel changeover switch 54a is turned on and the switch 55a is turned off, and the BPF 56 receives a photocurrent of 1 instead of 12.
1 voltage V1 is input. At this time, the integral timing pulse circuit 70 outputs the timing pulse e2 with the rRED drive pulse signal wave number delayed by half a cycle compared to when the channel changeover switch 55a is on, so that the filter output signal from the BPF 56 has a negative peak b
Integration (positive integration) is performed at step 2. In this way, each time the integrated output V1 exceeds the base Q voltage V rcf', the photocurrent 11. Signals proportional to I, , are integrated in opposite directions.

Now, the total number of integrations is N. Then, the number of positive integrations is N, and the number of inverse integrations is N. The relationship with S.

No-N50NG (3).

Also, the number of positive integrals N8 and the number of total integrals N. The relationship with is N −+12/ (11+12)l No・−・−(
4). Substituting the above equation (2) into this equation (4) gives the following equation.

Therefore, the total number of integrations N counted by the total number of integrations counter 63. is kept constant by the termination circuit 64, so the object distance Ω can be determined from the number of LE integrations N8 counted by the positive integration number counter 62.

FIG. 8 and FIG. 9 show the fll obtained by the above example.
FIG. 8 shows the theoretical value, and FIG. 9 shows the theoretical value when circuit noise is superimposed on it.

As is clear from FIG. 8, the dllj distance data N8 value obtained by the above embodiment becomes a straight line g1 connecting the measured distance values at the closest end and the infinite end. However, since there is noise in the actual circuit, the total number of integrations is N. As shown in Figure 9, NOl>No2.

In other words, Number of integrations N.

The larger the wife The longer A11+distance time, the higher the distance resolution becomes.

In this way, in the AF circuit shown in this embodiment, the total number of integrations is N. By switching, it is possible to switch between the first ranging mode and the second ranging mode.

That is, the termination circuit 64 shown in FIG.
1llll+distance mode switching signal S3 (see FIG. 2) to increase the total number of integrations N. For example, the 1111th
It can be switched to 64 times in the 1 distance mode and 16 times in the 2nd All+ distance mode, which results in 71+
11 distance time is 174 times the distance measurement time in the first side distance mode.
The 27th Illll distance mode can be realized.

FIG. 10 is a circuit diagram showing an example of the counter 63 and termination circuit 64 (see FIG. 6). In the figure, counter 6
3 is seven D-type flip-flop circuits (hereinafter referred to as DF/F).
) formed by 15 to 21 cascade connections, each DF
/F15-21 have their q output terminals connected to the D input terminals and operate as binary counters. Therefore, an integral timing pulse circuit 70 is connected to the input terminal T1 of this counter 63.
(See Fig. 6) When the timing pulse e output from the
A binary signal weighted ˜26 is obtained. Therefore,
DF in response to the 16th pulse of timing pulse e
An active H count signal S16 is output from the Q output terminal of the DF/F19 to the terminal T, and an active H count signal S16 is output from the Q output terminal of the DF/F21 to the terminal T in response to the 64th pulse of the timing pulse e. The count signal S64 will be output.

The termination circuit 64 consists of three Nant gates 22°23.24
．． ! : It is configured as an inverter 25, and the control means 7 (first
The counting signal S or S[f4
Either one is selected and outputted as an end signal from the output terminal T5. That is, when the logic level of the distance measurement mode 9) switching signal S3 is "H", the Nant gate 23 becomes active and the Nant gate 24 becomes non-active, so that the counter 63 is output from the output terminal T2, and this ends. A counting signal S16 manually inputted from the terminal T6 of the circuit 64 is sent to the terminal T via the Nantes gate 23°22.
It will be output from 5.

Also, the logic level of the dp1 distance mode switching signal S3 is “L”.
”, the signal S3 is inverted by the inverter 25 and supplied to the Nant gate 24, so the Nant gate 24 becomes active, and conversely, the Nant gate 23 becomes non-active.As a result, the output terminal of the counter 63 The number signal S64 outputted from the terminal T3 and inputted from the terminal T7 of the termination circuit 64 is transmitted to the Nandt gate 24.
22 and is output from the terminal T5.

That is, the counter 63 and termination circuit 64 shown in FIG. 10 are equivalent to the integral timing pulse circuit 70 shown in FIG.
The time width is set by switching whether to count 16 or 64 timing pulses e output from A11 in the 271st tl distance mode.
Switching is performed between the 1 distance time and the 4F1 distance time in the first side distance mode. The end signal outputted from the terminal T5 in this way is input to the CPU of the control means 7, and
A signal for terminating the distance measuring operation is sent from U to each part of the AF IC shown in FIG. 6.

The operation of this embodiment, which has been completed in this way, will be explained with reference to the flowchart shown in FIG. In this flowchart, each of the distance measurement points A, B, and C is measured in the second side distance mode, which takes a short distance measurement time, for example, No. , and this time only the distance measurement point I, for example N. -64 1st
I use distance measurement mode to find the dllll distance and extend the focusing lens.

At this time, since the distance resolution of the No. 16 271+++ distance mode is low as described above, two or all of the distance measurement data may be equal. However, in this case, I11+ in the center of the screen, where the probability that the main subject is present is higher.
Give priority to 1-distance point B, and place the same point B at N. -6
dll+distance in the first distance measurement mode of 4.

Also, the A11l distance data of distance measurement point B is the farthest data, and the distance measurement data of distance measurement point A and distance measurement point C
If the distance measurement data is small, do the following. In other words, in multi-point distance measurement using the second distance measurement mode, the flow is structured so that distance measurement is performed in the order of distance measurement points A, B, and C, so there is a time lag from the time of distance measurement to the actual shooting. Since the distance measurement point C is the shortest, priority is given to the distance measurement point C, and it is preferable to perform one-point all distance measurement in the first ApI distance mode.

First, in step S01, ll1ll distance point A, in step SO2, API distance point B, in step SO3, distance measurement point C, i'l? Measure the distance in two short-time distance measurement modes with I distance time and get the distance value ΩA” B'1
Find c. Next, in step SO4, the above three a
Al11 distance value gA of distance measurement point A from pj distance values
and i'1llll distance value gB of distance measurement point B are compared, and if "gB"A", proceed to step SO5.Step SO
In step 5, compare the 1ill distance value gB of the full distance point B with the /1111 distance value fIo of the distance measurement point C and obtain "g".
If “I) B < DA” in step SO4 above,
'', it is determined that All+distance point B is the closest.

In other words, which of the AI distance points A, B, and C is the closest is determined in the second All+distance mode, which takes a shorter distance measurement time.
In this case, the distance is 7Illll point B.
Since this is the closest distance measurement point B, it is considered that the main subject exists at this distance measurement point B. Therefore, the process proceeds to step S10, where the mode is changed to the first side distance mode with high distance resolution, and only the distance measurement point B is distanced by 7111 points with high accuracy. and,
Proceeding to step S13, the amount of lens extension is determined, and actual photography is performed.

Return to step SO5, if "gB ΩC" is not written, g
Since B≧ΩC, proceed to step SO6 and select “gB-”.
ρC” is determined. In the same step SO6, “gB”fl
If it is determined that "C" is not present, then gB > ρC, and since "pB x gA" was determined in step SO4, the all distance point C is determined to be the closest.Therefore, the process advances to step Sll and the JPI distance is determined. Point l-C No-64
The API distance is determined in the first jF+distance mode, and the lens extension amount is determined (step 813).

Returning to step S06, if it is "I) B-Dc", it is already "go to gB - g" in step S04. Now, distance measurement point A is the furthest distance and distance points B and C are If you use API distance in 2 distance measurement mode, it will be close at the same distance.As mentioned above, the probability that the main subject is in the center of the screen is more than 80%, so in this case, the main subject is at distance measurement point B. Considering that there is, step S10,
Proceed to 313.

If it's not "gBkuΩ8" when you go back to Sten Nbu SO4,
Since gB≧g^ should be true, proceed to step SO7 and select “N”.
-N" is determined. If "j713=Ω93A, the process proceeds to step SO8 and "gB"C" is determined. If "gB>fIo", "gB" is determined in step S07.
"="A", it is determined that the distance measurement point C is the closest. Therefore, the process advances to step Sll, 313.

Returning to step S07, if "I) B = 41A" is not found, perform the above self-step SO4 and "pB <rtA" is not found.
In other words, since ρ ≧ g, gB"AA is obtained. Therefore, the process advances to step S09 and "N l
" is determined, and if "gA"C", then C. Since N B-NA was reached in step SO7 above, the distance measurement point A becomes the closest one. Therefore, step S
Proceed to step 12 and move 4?1 distance point A to No. 1 of 64.
The distance is measured in the distance measurement mode, and the amount of lens extension is determined in step 313 based on this total distance value.

Return to step SO9 and if “gA” is not “C” then Ω＾≧
It should be a PC. Since gB>gA in step SO7 above, in this case there are two cases: iUI distance point B is the farthest and distance measurement points A and C are the same distance and closer, and distance measurement point C is the closest case. Two cases are possible. Therefore, if the former distance measurement point is the farthest and distance measurement points A and C are the same distance and closest, then il
? 1 distance point A has been distanced 71111 times in the above step SOI, and A11 distance point C has been distanced 71111 times in the above step SOI.
The distance was measured at 3. Therefore, the time lag between "determining the amount of feeding" (step 513) and actually photographing is naturally shorter in step SO3. So step SO3? If priority is given to the distance measurement data of the distance measurement point C obtained by '-J, the above two cases will be separated from the distance measurement point C or the nearest f11. Therefore, if "gA<gc" is not satisfied in step SO9, the process proceeds to step Sll, 513.

[Effects of the Invention] As described above, according to the present invention, since multi-point distance measurement is performed, the background is in focus and the main subject of the liver and kidneys is out of focus, which is a phenomenon called centering. is less likely to occur, and moreover, all of the multiple AFj distance positions are measured in the second distance measurement mode, which has low distance resolution but short distance measurement time, and the distance measurement position selected based on this distance measurement result is 41 in the first ranging mode, which has a long ranging time but high distance resolution.
Since the distance is 1, highly accurate AF can be realized and the release time lag can be shortened, which is a remarkable effect.

[Brief explanation of the drawing]

Fig. 1 is a block system diagram of the main parts of a multi-point ranging power camera showing an embodiment of the present invention, Fig. 2 is a block system diagram showing HL9H of the present invention, and Fig. 3 is a viewfinder field frame. 4(A) and (B) are diagrams showing the Δ-1 distance time required to distance each ranging point in FIG. A) is a case where all distance is measured from 3 points in the 111P1 distance mode, and FIG. Figure 5 is a diagram showing the distance measurement in each mode, and Figure 5 is an I + In the figure, 7 of AFJIIC in Figure 1 above is a block diagram showing the configuration of the air circuit, Figure 7 is a timing chart showing the waveforms of each part in Figure 6 above, and Figures 8 and 9 are , are diagrams showing the relationship between the distance measurement data N8 obtained in the above embodiment and the reciprocal of the object distance Ω, in which FIG. 8 shows the theoretical value, FIG. 9 shows the case where circuit noise is superimposed, and FIG. FIG. 10 is a circuit diagram showing a specific configuration of the counter 63 and termination circuit 64 in FIG. 6, and FIG.
It is a flowchart for explaining 1l distance operation.

Claims (1)

[Claims] (1) In a multi-point distance-measuring camera that measures the distance of the subject using multiple distance-measuring devices within the shooting image frame, the first distance-measuring mode takes a long time to measure the distance but has high distance resolution at each of the above positions. and a distance measuring means having at least two modes, a second distance measuring mode which has short distance measuring time but low distance resolution; and when measuring distance by this distance measuring means, all of the plurality of distance measuring devices are A control means for measuring a distance in a distance measurement mode, selecting a distance measurement device based on the result, and then causing the selected distance measurement device to perform distance measurement in the first distance measurement mode. Features a multi-point ranging camera.