JPH03218430A - Focal point detection photometry device - Google Patents

Abstract

PURPOSE:To obtain a photometric value with high reliability by setting a two-dimensional photometric area including the focal point detection area of two one-dimensional photoelectric converting means and interpolating the photodetection signal of this photometric area by the output signals of the two photoelectric conversion means. CONSTITUTION:At a photometry device equipped with the first pair of photoelectric conversion element trains equipped with a one-dimensional focal point detection area and the second pair of photoelectric conversion element equipped with the one-dimensional focal point detection area to cross this first pair, the two-dimensional photometric area is set while including the focal point detection areas of the two one-dimensional photoelectric conversion means. Next, the photodetection signal of the two-dimensional photometric area is interpolated based on the output signals of the two photoelectric conversion means so that the photometric value can be calculated from the interpolated photodetection signal. Therefore, there is no influence caused by the slight change of a picture angle, etc., from the output of the photoelectric conversion element train for focal point detection.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a focus detection photometer that obtains highly stable photometric values using a focus detection device using a CCD line sensor.

[Prior Art] Conventionally, there has been known a focus detection photometry device that obtains a spot photometry output at the center of a photographic screen based on a photoelectric conversion output of a focus detection device that performs focus detection at the center of the photographic screen. For example, JP-A-6
In No. 2-188916, C provided for focus detection
A device is disclosed that calculates the total average of pixel outputs of a CD line sensor and uses it as a photometric value at the center.

[Problems to be Solved by the Invention] However, in a photometer using such a conventional focus detection device, a so-called focus detection photometer, the 16th
When the focus detection area 100 has a cross-shaped two-dimensional shape as shown in the figure, the photometric value of a subject having a striped brightness distribution 102 as shown in FIG. Calculated from the total average, the 16th
When the angle of view is slightly changed as shown in Figure (B), the photometric value fluctuates greatly due to a slight change in the angle of view, which is about the same as the width of the line sensor element, resulting in a problem of lack of reliability and stability. Ta.

The present invention has been made in view of these conventional problems, and provides highly stable and reliable photometry that is unaffected by slight changes in the angle of view from the output of a photoelectric conversion element array for focus detection. It is an object of the present invention to provide a focus detection photometer that can obtain a value.

[Means for Solving the Problems] First, the present invention provides a first set of photoelectric conversion element arrays having a one-dimensional focus detection area, and a first set of photoelectric conversion element arrays having a one-dimensional focus detection area, and a first set of photoelectric conversion element arrays having a one-dimensional focus detection area. The present invention is directed to a focus detection photometry device including at least a second set of photoelectric conversion element arrays having an original focus detection area.

In the present invention, for such a focus detection photometry device,
A two-dimensional photometry area including focus detection areas of one-dimensional first and second photoelectric conversion means is set, and a light reception signal of the two-dimensional photometry area is converted into an output signal of the first and second photoelectric conversion means. A photometric calculation means is provided for interpolating based on the received light signal and calculating a photometric value from the interpolated received light signal.

Here, the photometric calculation means includes a correction coefficient calculation means for calculating a correction coefficient from an output signal of one of the photoelectric conversion means, and a correction coefficient calculated by the correction coefficient calculation means for converting the correction coefficient into an output signal of the other photoelectric conversion means. A photometric value calculation means for calculating a photometric value based on the multiplied values is provided.

Further, the correction coefficient calculation means converts the output of one of the photoelectric conversion means into c1, c2, . ..., cm, and the output signal of the intersection area with the other photoelectric conversion means is C kl + C
When k+2 + ..., C*++ is closed, the correction coefficient f (c) is 1(c) = ((c1+ ...+cm )/ml/
Calculate as t(cm.++=4ch.+)/+1.

Further, the photometric value calculation means calculates the photometric value by dividing a value obtained by multiplying the sum of the outputs of the other photoelectric conversion means by the correction coefficient by the accumulation time of the photoelectric conversion means.

[Function] According to the focus detection photometry device of the present invention having such a configuration, when calculating the photometry value of a subject that has a two-dimensional spread in the shooting screen, line sensors (focus detection elements) that intersect with each other are used. For example, in the case of an XY cross, it is assumed that the distribution state of the element row output of the line sensor in the Y direction also holds in the vicinity along the line sensor in the X direction, and at least two crossed The brightness of the object within the area covered by the line sensor, for example a rectangular area, is estimated and calculated.

Therefore, changes in the angle of view due to the width of the line sensor element, which were a problem in the past, have almost no effect because they are minute compared to the size of the area to be measured, and highly stable photometric values can be obtained. be able to.

[Example] First, the principle of the present invention will be explained regarding a focus detection photometer having a cross-shaped detection area 100 as shown in FIG.

In FIG. 1, the horizontal direction (X
A pair of light-receiving element rows (photoelectric conversion element rows) in the vertical direction (direction) are referred to as rows A and B, and the light-receiving element rows in the vertical direction (Y direction) are rows C and D.
column.

Here, the light receiving data obtained by AD converting the light receiving output of the A and B rows in which n light receiving elements are arranged are A=a1, a2.
, ・●e, anB=b1, b2, - ms, b
n, and C row in which m light receiving elements are arranged. The received light data obtained by AD converting the received light output of column D is C: c1, c2,
−●●, cm D=d1, d2, −@−, dm. For example, when the amount of dust during the differential is zero (in focus), the received light data A and B are obtained by re-imaging the light beams that have passed through different pupil areas of the photographing lens for the same subject. Therefore, they are the same value. Therefore, the value of (A+B)/2 may be used as the brightness information of the subject, or only either A or B may be used. The same applies to the received light data C and D. Hereinafter, the description will be made assuming that the received light data A and C are used as the luminance information.

Next, FIG. 2 shows an example of the brightness distribution of a subject.

In FIG. 2, light-receiving element rows A are arranged on the X-axis, and light-receiving element rows C are arranged on the Y-axis. The E axis perpendicular to the X and Y axes represents the brightness of the subject.

As the photometric value for the subject shown in FIG. 2, the average height of the three-dimensional object, 100, or the average subject brightness, as shown by the broken line in FIG. 3, is used. Now, if we pay attention to the detection areas of the light-receiving element rows A and C, the data rows a1 to a of row A are the fourth
As shown in Figure (A), it is the brightness distribution information of the X-axis cross section of the solid in Figure 2, and similarly, the data strings 01 to cffi in column C are as shown in Figure 4 (B). This is brightness distribution information of a three-dimensional Y-axis cross section.

In normal photographing, the size of the subject is sufficiently larger than the focus detection area, and the brightness distribution also has a two-dimensional spread with respect to the photographic screen. Therefore, as a method to find the average height (subject average brightness) of "100" of the solid shown in FIG. For example, assuming that the output distribution state of the light-receiving element row C in the Y-axis direction also holds in the vicinity of the other light-receiving element row, for example along the light-receiving element row 8 in the X-axis direction, two intersecting light-receiving element rows A,
A method of calculating the average brightness of the subject within the rectangular area covered by C is used.

Now, as shown in FIG. 5, the light receiving elements A1 to An and C of row A
If we pay attention to the intersection area of the light receiving elements C1 to Cm in the column, we can see that A,-1 to A,,1 and C,1 to Ck+ exist in the intersection area.
Each of the three light receiving elements 1 and 1 measures the same area. Therefore, the sum total of the outputs of the light receiving elements in columns A and C in the intersection area becomes the same value.

(ar-+ + aH + aH.,)=(C
*-, +C * 10C m-+) Here, output data C, ~C of the light receiving elements of column C.

can be regarded as brightness distribution information of a cross section of the subject in the Y-axis direction in the vicinity of the photometric area of the light receiving element Aj in the X-axis direction. That is, the data obtained by measuring the luminance distribution of the subject along the Y-axis at the X-axis coordinate position where the light receiving element Aj is located is 01 to C. So, this Y
For the average photometric output of the axial section (C+ +C2 +-.-+c Il1 )/m, the light receiving elements Aj in the A row output photometric data a1 as the photometric output.

Therefore, the average photometric data al' of the Y-axis slice section at the position corresponding to Aj on the X-axis can be expressed as the following equation.

a, = (c, +C2...+cm)/m(C
k-1 ”Ck +chv+ )X(c+/f(ch-
+ +Cm +Ch-t)Xml1+-1+i+ +
al-1 )X(c, +c2 +-+cm)/((c
．． −, +ck+Ch. +) xml4a, x3x
(c, +e2...+cm)/t(am-,
+c, +Ch−+ ) Xml”ar Xi(Cl
+C2 +...-+cm )/ml/ ((ch-+
+ch +Ch++ )/31・a, is 1(c) ”i(Ct +e2+-+c-)/+nl/t(ch
−+ +eh +el++ )/31... (2) It is obtained as follows.

Similarly, A 7-1 corresponding position, AI+1 corresponding position, 8''-
2 corresponding position, A1 corresponding position, An corresponding position also A
It can be thought of as a luminance distribution in the Y-axis direction that is similar to the j-corresponding position,
As average photometric data, a+-+' = 81-IX
f (C)a+-+' = 3,,X f (c)
a,'=a,xf (c) is obtained. Therefore, the average photometric data of the rectangular area is expressed by the following formula.

a' = (a+ +a2+-・+a,)X f (c
)/n...(3) This equation (3) is finally summarized as the following equation.

a'l(a, +-+a.)x(c, ten-+
Axis )X31/inXmX(cm-+ +ck +Ck
−+ )l ” ' (4) and (4th
) The photometric value can be obtained by dividing the value calculated from the formula by the CCD storage time and multiplying the result by a predetermined coefficient.

? The above is the principle of photometric value calculation according to the present invention, and a flowchart of the algorithm for realizing this is shown in FIG.

First, Fig. 6 Step Sl (steps are omitted below)
The pixel output a1 from the light receiving elements A1 to An in column A is as follows.
Calculate the integrated value Σa of ~a.

Next, the process proceeds to 82, where the integrated value ΣC of the pixel outputs 01 to C■ from the light receiving elements 01 to Cm in column C is calculated.

Next, in step 83, the pixel output integrated value S of the vertical and horizontal column overlap portion is calculated from the three pixel outputs C k-1 to C k+1 of column C in the overlap portion of column A and column C, which are vertical and horizontal.

Next, as shown in S4, the average photometric data a' of the rectangular area is calculated, and finally, the average photometric data a' is divided by the CCD accumulation time T and multiplied by a predetermined coefficient B to calculate the photometric value, as shown in 85.

Next, an embodiment in which the focus detection photometry device of the present invention is applied to a single-lens reflex camera will be described with reference to FIG.

In FIG. 7, a lens 10 that is replaceable with respect to a camera body 20 is detachably mounted on a mount. When the lens 10 is attached, a part of the photographic light beam arriving from the subject passes through the photographic lens 11 and is reflected by the main mirror 21 provided on the camera body 20 and guided to the finder, and the other part is reflected by the main mirror 21. The light is transmitted through the sub-mirror 22, reflected by the sub-mirror 22, and guided to the AF module 30 as a light beam for focus detection photometry.

An example of the configuration of the AF module 30 is shown in FIG.

In FIG. 8, the AF module 30 is connected to a field mask 31.
, field lens 32 and two pairs of re-imaging lenses 28A. A focus detection optical system 25 consisting of 28B, 29A, and 29B, and two pairs of light receiving sections 38A, 38B, and 39A.
, 39B, and a photoelectric conversion means 35 such as a CCD.

In such a configuration, two sets of regions 18A, 1 are symmetrical with respect to the optical axis 17 included in the exit pupil 16 of the photographic lens 11.
8B and area 19A. The light beam passing through 19B forms a primary image near the field mask 31, which has an aperture shape corresponding to the entire focus detection area as shown in FIG. Field of vision mask 3
A part of the primary image formed in the first aperture is further transmitted through a field lens 32 and two sets of re-imaging lenses 28A, 28B and 2.
9A. 29B, two sets of light receiving sections 3 of the photoelectric conversion means 35
A pair of secondary images are formed on 8A, 38B and 39A, 39B, respectively.

As is well known, the amount of defocus of the photographic lens can be detected by detecting the relative positional relationship of the paired secondary images in the direction in which the light receiving sections are arranged on the photoelectric conversion means 35.

FIG. 9 shows the arrangement of the light receiving section on the photoelectric conversion means 35. The light receiving sections 3gA and 38B each include n light receiving elements A1 to A.
nSBl to Bn, and are arranged so that when the primary image coincides with the film surface (in focus), the outputs of the corresponding light receiving elements, that is, A1 and B1, A2 and B2, etc., are equal. ing. Light receiving section 39A. The same applies to 39B.

Light receiving section 38A. 38B. The light-receiving elements forming 39A and 39B are composed of charge storage elements such as photodiodes, and the light-receiving element output is adjusted to an appropriate level by accumulating charge for a charge accumulation time corresponding to the illuminance on the photoelectric conversion means 35. The output level can be controlled.

Referring again to FIG. 7, the sensor control means 40
Receives charge accumulation start and end commands from boat P3 of UIOO, and converts control signals according to the commands to photoelectric conversion means 35.
The charge accumulation time of the photoelectric conversion means 35 is controlled by giving . In addition, the transfer clock signal etc. is transferred to the photoelectric conversion means 3.
5 and transfers the light receiving element signal output to the CPUIOO in time series, and also sends a synchronization signal synchronized with the start of transfer of the light receiving element signal output to the boat P3 of the CPUIOO.

CPUIOO synchronizes with this signal and uses the built-in AD conversion means to AD convert the light receiving element output signal input to boat P1.
Conversion is started and AD conversion data corresponding to the number of light receiving elements is obtained. When the AD conversion is completed, the obtained data is converted into
The amount of defocus is detected using a point interpolation method or the like.

After processing the data and calculating the defocus amount, the CPU IOO controls the display form of the display sections 51.52, 53.54 of the AF display means 50 based on the defocus amount using the port P2. Further, the setting information (AF mode, MF mode) of the AF mode selection means 76 is sent to port Pll of CPUIOO, and when setting the AF mode, CPU 1
．． 0 0 is the AF motor 60 based on the defocus amount.
The driving direction and amount of driving are controlled using the boat PL2, and the photographing lens 11 is moved to the focal point via the photographing lens drive system 65.

In parallel with or chronologically following the calculation of the defocus amount, the CPUIOO performs data processing according to the algorithm shown in FIG. 6 based on the obtained data and calculates a photometric value. Further, photometric values other than spot photometric values are calculated based on the output signal of the photometric means 90 sent to port P5. The CPUIOO selects the display section 81.8 of the photometry display means 80 based on the setting information of spot photometry or other photometry mode of the photometry mode selection means 78 sent to port P9.
2 is controlled using port P4. Further, setting information of the AE mode selection means 77 (manual, shutter priority AE, aperture priority AE,
Depending on the program AE, daylight synchro, etc.),
Based on the calculated photometric value, the CPUIOO controls the shutter control means 70, the aperture control means 72, and the strobe control means 74 using buttons P6 to P8, either singly or in parallel, to provide proper exposure to the film.

The above is an overview of the configuration and operation of an embodiment in which the focus detection photometry device according to the present invention is applied to a single-lens reflex camera.

Next, it will be explained that the photometric value calculation method of the present invention is more stable than the conventional photometric value calculation method.

As a conventional example, a method is known in which photometric data is calculated as a total average of light-receiving element data.

The calculation formula is as follows.

a = (a, +a2+-+a. +C, +c2
...+cm )/(n+m) Now, consider an object having the luminance distribution shown in FIG. At the first photometry, n=9
Light reception data al to a99 of nine light receiving elements A1 to A99
Suppose that has the value shown in FIG. 11(A), and light reception data 01 to c49 of m=49 light receiving elements C1 to C49 have the values shown in FIG. 11(B).

In this case, the photometric data a'' according to the conventional method and the photometric data a゜ according to the present invention are as follows.

[Conventional] a = (a, +a2+・=+a, JC1 +C2+・
”c49) / (99+49)= f (200x9
9) + (50x23) + (200x26) +
/148=25150/14g =177 [This invention] a' = ((at +-=・1899] X (C
I +-+C49J X31/i (99X49X
(c24+c25+c26)1=[(200X99
)+f(50X23)+(200X26)lX3]/
+99 x 49 x (200 become that way.

[Conventional] a = t (50x99) + (50x26) + (200
x23))/14873 U Invention Core a' l(50X99)Xi(50d6)+(200x
23)lX3]/ +99X49X (50X3) 1
・120 As is clear from this specific example, according to the conventional method, the photometric data decreases by 59% due to a slight change in the angle of view, whereas according to the method of the present invention, the change is reduced to 9%. .

The change in photometric value according to the method of the present invention in response to a change in the angle of view is similar to the change in the photometric value of the spot metering method using a conventional SPD light receiving element, which is similar to the conventional method, and there is no discomfort for the photographer, as it is similar to the conventional method. Easy to operate.

As described above, the focus detection photometer according to the present invention can obtain photometric values with high stability and good operability, but the method for calculating photometric values is not limited to the above.

As an application example of the calculation method of the present invention described above, by multiplying the light receiving element data by a weighting coefficient in accordance with the position of the light receiving element, a center-weighted spot photometer or a downward-weighted spot photometer can be obtained. is also possible.

An application example of multiplying weighting coefficients will be described below.

If the weighting coefficient for the pixel outputs C, ~c1 of the light-receiving elements C1 to Cm in column C is V l """ V m, then the above equation (2) for calculating the correction coefficient f (c) is as follows: It can be changed.

f(c)・[(▼,XC,)+(v2 XC2)
+-+( vm Xc,, Month/(▼1+▼2+・
・・＋▼, )1 /[{(▼*-+ xck-1 )+(vi XCm
)+(wb-+xck-1)1/(vl-1+
Vh +Vh. +)1・・・・(5) Next, the pixel outputs a1 to a of the light receiving elements A1 to An in column A,
If the weighting coefficients are u1 to u, then the average photometric data with weighting coefficients of the Y Tsumugi slice section at any position corresponding to Ai? 1′ becomes the following equation.

at' = l1, Xal xf (c) 10. (6) Therefore, the light receiving elements A1 to An and C of row A
The above-mentioned equation (3) for calculating the average photometric data of the rectangular area constituted by the light receiving elements 01 to Cm in the column is weighted according to i and becomes the following equation.

a'■[i( ul Xa+ 14(++2 Xa2)
+−+(o. xa, )lXf(c)]/(u+ +
l+2 +-+I+. ) φsan〇 (
7) Weighting coefficients u1 to u. and v1-V. may be a variable that changes continuously and smoothly, or in order to simplify the calculation, several intervals may be set and the values may be set so that the weighting changes stepwise.

To give an example of the center-weighted method, Fig. 17 (A) to (
As shown in C), the light receiving elements Al to An in the A column and the light receiving elements 01 to Cm in the C column are each divided into three sections, and the weighting coefficients for each section may be set as follows.

Regarding column A (Al to An), the following three sections are weighted as shown in FIG. 17(A). ; Section l≦i<(n/3): ul = 1 section (n/3)≦1≦I(2xn)/31: u,
・2 sections 1(2Xn)/31 <i≦n: u
．．・Similarly, the IC columns (Cl to Cm) are weighted as shown in FIG. 17(B). ; Section 1≦” (m/3): 71 = 1
Interval (Ql/3)≦+≦((2xml/31:
V. =il interval {(2χm) /31 <
1≦m: y, =1 Therefore, when weighting is performed for columns A and C as described above, the shape of the photometric sensitivity distribution (relative sensitivity due to weighting) in the rectangular area is as shown in FIG. 17 (C).
It becomes as shown in .

In addition, to give an example of the downward focusing method, in FIG. 7, when the CPUIOO determines by an attitude detection means (not shown) that the C direction of the light receiving elements in the C row is the sky and the Cm direction is the ground. , the weighting coefficient for each section may be set as follows.

Regarding column A; interval 1≦1< (n/3): 01 =
1 section (n/3)≦1≦((2Xn)/31:
u, = 2 sections 1(2Xn)/31 <i≦n
: Regarding L = 1C column: Section 1≦i<(m/3): V+ = 1 section (m/3)≦1≦l(2Xm)/31: v.
= 2 sections 1 (2Xm) /31 < i
≦m: v, =2 Note that the division of the section is not limited to three, and the allocation of weighting coefficients is not limited to the above.

The weighting coefficient is determined by the CPUIO depending on the characteristics of the light receiving element data.
O may be selected automatically, or the photometry mode selection means 7
8 or the AF mode selection means 76.

Multiple weighting coefficients can be set, and depending on the coefficient
As shown in FIGS. 3(A) to 3(C), depending on the setting of the center weight on the photometric display means 80, similar to the contour line display of a map, when the center weight is low, the display shown in FIG. 13(A) is displayed. 13(B) when the central emphasis is medium, and as shown in FIG. 13(C) when the central importance is high.

In addition, the output contrast of the light receiving element data is shown in Figure 10 (
Even more extreme than the examples in B) and Figure 11 (B), if the reliability of the data in the low output area is extremely low, or if it is determined that there is clearly no continuity of the subject, the photometric value calculation may be The area may be limited. For example, if the output near the last received light data an in column A is extremely low, or if the output near the first received light data a1 and the last received light data an is extremely low, the output is shown in FIG. 14 (A). From the area display of the photometric display means 80, the limited photometric value calculation area shown in FIGS. 14(B) and 14(C) is displayed.

Furthermore, as an example of the photometric value calculation algorithm of the focus detection photometer according to the present invention, first, a correction coefficient is obtained from the element outputs of the vertical light receiving element rows, and then the correction coefficient is multiplied by the sum of the element outputs of the horizontal light receiving element rows. We have shown an algorithm for calculating photometric data, but in reverse, we first find a correction coefficient from the element outputs of the horizontal photodetector arrays, and then multiply it by the sum of the element outputs of the vertical photodetector arrays to calculate the photometric data. calculate? Of course, an algorithm may also be used.

Specifically, A, which is the vertical and horizontal direction at 83 in FIG.
The pixel output integrated value S of the C column overlap part is all ~ a
It may be calculated from j1.

(a+ + +a, +a,, ) and (Ck+ +C
i +ck. I) have the same value, so the calculated photometric data will also be the same.

Furthermore, although this embodiment has been described using a cross-shaped detection area as a similar two-dimensional shaped detection area, in the case of an H-shaped detection area as shown in FIG. ~C, and using the received light data e1~e■ of column E,
For the area sandwiched between the light-receiving element rows C1-Cm and E1-Em, the correction coefficient g (c) obtained from C1-c and the correction coefficient g (c) obtained from e1-e6 using the method explained in the specification of the present invention. It is also possible to multiply a, ~a, using an intermediate value of the coefficient g (e).

To be more specific, C in the intersection area of column A and column C
The light reception data of the column is C, -1 to Ck. 0 when l
1 to C, the correction coefficient g (c) obtained from the following equation.

g (C) + (CI +c, +=-+c.)/ml/ f(ck
-1 +Ck +Cb-+ )/31... (8) On the other hand, the light reception data of column E in the intersection area of column A and column E is
, -1~e,. 1, e1 to e. The correction coefficient g(e) obtained from , , is similarly expressed as the following equation.

g (C) ・{(e+ +e2+-+e-)/ml/i(ek-
, +eb +ek-+ )/31... (9) If a simple average is used as the intermediate value of the above two correction coefficients, the correction coefficient to be multiplied by a1 to a,, is g(c, e )Ig(c)+g(!)l/2 e
@ @ (1 0), and the average photometric data a1 with a weighting coefficient of the Y-axis slice section at an arbitrary position corresponding to Ai is given by the following formula.

a. ' = u. xa. xf (c) Therefore, the average photometric data of the rectangular area is finally given by the following equation.

a' = I(a, +a2 +=-+a,)Xg
(c, e) l/n・[f(al +a2+...10a,
) X31 / (nxmx2) ]X[FC! +(
2+-+c, )/ (Cm-+ +Ch +Ch-+
)IN(6, +e2+-+6,)/(ek-1 +e
k+ek. I)11... (11) Note that the method for determining the intermediate value correction coefficient is not limited to the above method. Also, to simplify calculation, g (c
) and g (e) can be considered to be substantially the same, g (c. e) = g (c). In this case, equation (8) is the same as equation (4). Furthermore, it is obvious that the same holds true even when g (c.e)=g (e). It goes without saying that the weighting coefficients can also be multiplied together.

Also, a, ~a. The interpolation correction coefficient h (i) may be determined according to the distance from columns C and E of , and multiplied by a, "wa,".

The method for determining the interpolation correction coefficient h(i) will be explained below.

The correction coefficient g (C) obtained by the above equation (5) is A
This is a correction coefficient based on brightness distribution information of a cross section in the Y-axis direction of the subject in the vicinity of the photometric area of the light receiving element A1 in the column. Further, the correction coefficient g (e) obtained by the above equation (6) is a correction coefficient based on the luminance distribution information of the Y-axis direction cross section of the subject in the vicinity of the photometry area of the light receiving elements An of the A row.

Therefore, among the light receiving elements A1 to An in row A on the X axis, the average photometric data a+' of the Y axis slice section at a position corresponding to Ai at an arbitrary position is as follows: at' = a+ xg (if Ai is close to A1) c) If Ai is close to An, it can be considered that at' ==3,Xg (e). Also, if Ai is located between A1 and An, a L' = a + x Ig(c) +g(e)
It can be regarded as l/2.

From the above relationship, the interpolation correction coefficient h (i) as a function of i representing continuous position can be expressed as the following formula.

b(i)II(n-i+I)Xg(c)l+I(i-
1) .

al'=h(i)Xal---(13) Furthermore, the average photometric data of the rectangular area formed by the light receiving element arrays C1 to Cm, El to Em, and A1 to An is expressed by the following equation.

! '=((!, Xh(1))+( a2Xh(2+)
+. +(1, xh(n))l/n... (14) Note that the ability to find the interpolation correction coefficient h(i) is not limited to the above. For example, to simplify calculation, A
The light receiving elements A1 to An in the row may be divided into three sections, and the interpolation correction coefficient h (i) for each section may be represented by the following numerical value.

? Between 1≦1<(n/3): h(i)=g(
c) Section (n/3)≦i≦f(2xn)/31 :h
(i) Ig(c)+gfe)l/2 section t(2X
n)/31 <i≦n: h (i) ■g (e)
Furthermore, the division of the section is not limited to three. It goes without saying that the weighting coefficients can also be multiplied together.

[Effects of the Invention] As described above, according to the focus detection photometry device of the present invention, it is possible to avoid large fluctuations in photometry values due to slight changes in the angle of view, and stable photometry values can be obtained with high accuracy. Furthermore, since it has characteristics similar to conventional spot photometry, it has good operability.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the detection area of the present invention; Figs. 2 and 3 are explanatory diagrams of an example of the luminance distribution of a subject; Fig. 4 is an explanatory diagram of the light receiving element output corresponding to Figs. 2.3; FIG. 5 is a partially enlarged view of the detection area; FIG. 6 is a block diagram related to light value calculation of the focus detection photometer according to the present invention; FIG. 7 is a block diagram of the focus detection photometer according to the present invention;
Figure 9 is an explanatory diagram of the detection optical system used in the present invention; Figure 9 is a configuration diagram of the photoelectric conversion means; Figure 10 is an explanatory diagram of an example of the brightness distribution of another subject:
Fig. 12 is an explanatory diagram of the light receiving element output corresponding to Fig. 10. Fig. 13 is an explanatory diagram of an application example of the photometry mode display means;
Figure 4 is an explanatory diagram of another application example of the photometry mode display means; Figure 15 is an explanatory diagram of another example of the detection area; Figure 16 is an illustration of the conventional problem when the angle of view is slightly changed. FIGS. 17(A) to 17(C) are explanatory diagrams showing an example of a sensitivity distribution shape in an applied example in which weighting coefficients are multiplied. [Explanation of symbols of main parts] 10: Photographing lens 20 Camera body 30, AF module 50, AF display 60: AF motor 80: Metering mode display 100: CPU

Claims (4)

[Claims] (1) A first photoelectric conversion means having a one-dimensional focus detection area, and a second photoelectric conversion means having a one-dimensional focus detection area intersecting the focus detection area of the first photoelectric conversion means. In a focus detection photometry device comprising at least and a photometric calculation unit that performs interpolation based on the output signal of the second photoelectric conversion unit and calculates the photometric value of the two-dimensional photometric area from the interpolated light reception signal. (2) The photometric calculation means includes correction coefficient calculation means for calculating a correction coefficient from the output signal of the one photoelectric conversion means;
and a photometric value calculating means for calculating a photometric value based on a value obtained by multiplying the output signal of the other photoelectric conversion means by the correction coefficient calculated by the correction coefficient calculating means. Device. (3) The correction coefficient calculation means sets the output of one photoelectric conversion means to (c1, c2, . ..., ck+i),
The correction coefficient f(c) is expressed as f(c)=((c_1+...+c_m)/m)/((
The focus detection photometry device according to claim 1, wherein the calculation is performed as c_k_+_1+...+c_k_+_i)/i). (4) The photometric value calculation means calculates the photometric value by multiplying the sum of the outputs of the one photoelectric conversion means by the correction coefficient, and then dividing by the accumulation time of the photoelectric conversion means. The focus detection photometry device according to claim 1.