JP4288416B2 - camera - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a camera including a focus detection unit that detects a focus adjustment state of a photographing lens based on an output of a photoelectric conversion unit.
[0002]
[Prior art]
Conventionally, a subject image formed by the focus detection optical system is received using a charge storage type sensor, and the sensor output is calculated to detect the defocus amount of the subject image plane with respect to the planned focal plane of the photographing optical system. There is known an automatic focus adjustment camera that achieves focusing of a photographing optical system by driving a focusing lens according to a defocus amount.
[0003]
Further, as disclosed in Japanese Patent Laid-Open No. 6-273665, a plurality of focus detection optical systems and sensors are provided, and focus detection is performed in a plurality of areas set on the photographing screen to obtain a plurality of defocus amounts, A camera having a multi-area automatic focus adjustment device that determines one final defocus amount based on these defocus amounts and drives a focusing lens in accordance with the defocus amount to achieve focusing of the photographing optical system It has been known.
[0004]
On the other hand, in recent years, as disclosed in JP-A-4-310930, JP-A-6-281994, and JP-A-7-84299, a subject image is divided into a plurality of areas, and a plurality of subject lights in each area are divided. For example, the level detection is performed for each color component by separating the three primary colors of R, G, and B, and a plurality of detection results obtained by weighting the detection results for each color component, and the maximum value or the maximum value of the plurality of detection results are obtained. The exposure control value is used intensively, and the aperture value and shutter speed are calculated based on this exposure control value, and exposure control is performed, so even if a scene with many single colors such as red or blue is shot, it is overexposed. There has been devised an exposure control device for a camera that takes into consideration the color of a subject that can obtain a photograph with excellent color reproducibility.
[0005]
Furthermore, combining the multi-area automatic focus adjustment device and the exposure control device that takes into account the subject color, faithfully reproduces the subject color that exists in the AF area selected by the user or the AF area automatically selected by the camera. A camera has also been devised.
[Patent Document 1]
JP-A-6-273665 [Patent Document 2]
JP-A-4-310930 [Patent Document 3]
JP-A-6-281994 [Patent Document 4]
JP-A-7-84299 [0006]
[Problems to be solved by the invention]
However, in order to construct a camera that faithfully reproduces the color of a subject existing in the AF area selected by the user or the AF area automatically selected by the camera, the conventional camera is different from the conventional photometric device. The problem is that an optical system for decomposition and a photometric element for each color, or an extremely multi-segment photometric sensor with R, G, B color filters attached to each photometric area is required, resulting in a very expensive system. was there.
[0007]
The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a camera that can easily and reliably reproduce the color of a subject existing in an AF area (focus detection area). .
[0008]
[Means for Solving the Problems]
The camera according to claim 1 includes a photoelectric conversion unit having a plurality of light receiving elements that receive a light beam from a subject through the photographing lens, and detects a focus adjustment state of the photographing lens based on an output of the photoelectric conversion unit. In the camera including the focus detection unit, a plurality of color filters are provided for each of the blocks obtained by dividing the plurality of light receiving elements for each of the plurality of light receiving elements, and the plurality of color filters are provided based on outputs of the plurality of light receiving elements. a photometric means for detecting luminance information of the object, and a color detection means for detecting the color information of the object based on the output of each block of said light receiving elements receiving the light beam through the color filter, of the subject A correction unit that corrects an error of the luminance information due to color based on the color information; and the subject based on the luminance information corrected by the correction unit. And an exposure calculation means for calculating an exposure value.
[0009]
The camera according to claim 2 is the camera according to claim 1, further comprising a plurality of photoelectric conversion means corresponding to each of the plurality of areas set in the photographing screen defined by the photographing lens, The luminance information for each of the plurality of regions is detected based on the outputs of the plurality of photoelectric conversion units, and the color detection unit is configured for each of the plurality of regions based on the outputs of the plurality of photoelectric conversion units. The color information is detected, the correction unit corrects the luminance information for each of the plurality of photoelectric conversion units, and the exposure calculation unit is based on the luminance information corrected for each of the plurality of photoelectric conversion units. And calculating the exposure value.
[0010]
According to a third aspect of the present invention, in the camera according to the first or second aspect of the present invention, the camera includes a second photometric unit that detects luminance information of the shooting screen, and the exposure calculation unit includes the corrected luminance information and the corrected luminance information. The exposure value is calculated based on luminance information obtained by the second photometric means.
According to a fourth aspect of the present invention, in the camera according to the third aspect, the second photometric means detects the luminance information for a region other than the focus detection region set in the photographing screen.
[0011]
(Function)
In the camera according to the first aspect, the color filter is disposed on the light receiving surface of the photoelectric conversion means of the focus detection means, and the color information of the subject is detected by receiving the light flux through the color filter.
Then, the luminance information is corrected based on the color information, and an exposure value for the subject is calculated based on the corrected luminance information.
[0012]
According to another aspect of the camera of the present invention, a plurality of photoelectric conversion means are arranged corresponding to each of the plurality of regions set in the photographing screen defined by the photographing lens, and color information for each of the plurality of regions is detected. .
Based on this color information, the luminance information is corrected for each of the plurality of photoelectric conversion means.
[0013]
In the camera according to the third aspect, the exposure value is calculated based on the luminance information corrected by the color information of the photoelectric conversion means and the luminance information by the second photometry means.
According to another aspect of the camera of the present invention, the second photometric means detects luminance information for an area other than the focus detection area set in the photographing screen.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 shows the configuration of an embodiment of the camera of the present invention.
The camera of this embodiment has a camera body 1 and a photographing lens 2 that can be attached to and detached from the camera body 1.
Then, the subject image is reflected upward by the main mirror 3 through the photographing lens 2 and is formed on the screen 4. The photographer can view the subject image formed on the screen 4 from the viewfinder 7 through the pentaprism 5 and the eyepiece 6.
[0016]
On the other hand, the central portion of the main mirror 3 is a half mirror, and the subject image that has passed through the half mirror is reflected by the sub mirror 10, and a multi-area focus detection unit 11 that detects the focus of a plurality of areas in the shooting screen. Is incident on.
The output information of the multi-area focus detection unit 11 is input to the control circuit 12, and based on the information, the control circuit 12 controls the AF motor 13 to drive the focusing lens 14 to focus the subject image.
[0017]
Further, the control circuit 12 controls the aperture 15, the shutter 16, and a mirror lifting mechanism (not shown) to expose the subject image on the film.
FIG. 2 shows the configuration of the multi-area focus detection unit 11 of the camera of this embodiment.
In this multi-area focus detection unit 11, the subject image reflected by the sub-mirror 10 and incident on the multi-area focus detection unit 11 passes through the opening corresponding to each AF area of the mask 21, and the condenser lenses 22, 23, The light passes through 24, 25 and 26 and is reflected by the mirror 27, and is imaged on the individual CCD line sensors on the three sensor chips 33, 34 and 35 by the separator lenses 28, 29, 30, 31, and 32, respectively.
[0018]
FIG. 3 shows an AF area in the shooting screen of the camera of this embodiment.
The AF area 41 is an AF area having a vertical detection range on the right side in the shooting screen G, and the AF area 42 is an AF area having a horizontal detection range on the right side in the shooting screen G.
The AF area 43 is an AF area having a detection range in the horizontal direction at the top in the shooting screen G, the AF area 44 is an AF area having a detection range in the vertical direction at the center in the shooting screen G, and the AF area 45 is a shooting screen. An AF area having a lateral detection range at the center in G, and an AF area 46 are AF areas having a lateral detection range in the lower part of the shooting screen G.
[0019]
The AF area 47 is an AF area having a vertical detection range on the left side in the shooting screen G, and the AF area 48 is an AF area having a horizontal detection range on the left side in the shooting screen G.
The CCD line sensors corresponding to the AF areas 41 and 42 are arranged on the sensor chip 33 shown in FIG. 2, and the CCD line sensors corresponding to the AF areas 43, 44, 45 and 46 are shown in FIG. The CCD line sensor arranged on the sensor chip 35 and corresponding to the AF areas 47 and 48 is arranged on the sensor chip 34 shown in FIG.
[0020]
FIG. 4 shows the arrangement of the CCD line sensor on the sensor chip 35 of the camera of this embodiment.
The CCD line sensors 51 and 52 are CCD line sensors corresponding to the AF area 43 shown in FIG. 3, and the image of the AF area 43 is decomposed into two images by the separator lens 29. The images are separately formed on 52.
[0021]
Then, the defocus amount is obtained by calculating the correlation between the outputs of the elements on the two CCD line sensors 51 and 52.
Similarly, the CCD line sensors 53 and 54, 55 and 56, and 57 and 58 are CCD line sensors corresponding to the AF areas 44, 45, and 46 shown in FIG.
[0022]
FIG. 5 is an enlarged view showing portions A and B of FIG. 4 as an example of the configuration of the CCD line sensor.
In this embodiment, color filters having wavelength characteristics R, G, and B as shown in FIG. 6 are mounted on the individual light receiving elements of the CCD line sensors 55 and 56.
In FIG. 5A, there are small blocks A1 to A7, and each block is composed of three elements on which color filters having wavelength characteristics R, G, and B are mounted.
[0023]
Similarly, in part B of FIG. 5, there are small blocks B1 to B7. Each block is composed of three elements each having a color filter having wavelength characteristics R, G, and B as shown in FIG. It is configured.
FIG. 7 shows a commonly known xy chromaticity diagram.
In this xy chromaticity diagram, three points GP (Gx, Gy), BP (Bx, By), and RP (Rx, Ry) are set in advance according to the filter characteristics of the color filter shown in FIG. From each R, G, B output of the small block
x = R / (R + G + B) .. Formula 1
y = G / (R + G + B) .. Formula 2
If x and y are obtained by the above, it is possible to know the color of the subject corresponding to each small block depending on where x and y exist in the triangle connecting the three points.
[0024]
That is, when considering the XY coordinate system as shown in FIG. 8 in which the triangle is rotated by θ around the point (0.33, 0.33), the inside of the triangle is divided into seven parts as shown in FIG. It can be divided into areas (white area E1, yellow area E2, yellow-green area E3, green area E4, blue area E5, purple area E6, and red area E7).
[0025]
Here, the circle partitioning the white area E1 is obtained by the equation X ² + Y ² = r ² (eg r = 1.15).
The straight lines L1 and L2 are obtained, for example, with Y = √ (formula 2), and the straight lines L3 and L4 are obtained with Y = −√ (formula 2), respectively.
On the other hand, the X and Y coordinates in this XY coordinate system are obtained by using the above x and y.
X = (x−0.33) cos θ + (y−0.33) sin θ.
Y = one (x−0.33) sin θ + (y−0.33) cos θ.
However,
sin θ = (Ry−By) / √ {(Rx−Bx) ² + (Ry−By) ² }
The subject color of the small block can be recognized depending on which color area in FIG. 8 the calculated coordinates (X, Y) belong to.
[0026]
The operation of automatic exposure control and automatic focus control by the control circuit 12 will be described below based on the flowchart shown in FIG.
In this embodiment, when a release button (not shown) is operated, first, charge accumulation for a predetermined time is executed for all the CCD line sensors of the sensor chips 33, 34, and 35 in step S1.
[0027]
Subsequently, in step S <b> 2, the charges accumulated in each light receiving element of the CCD line sensor are A / D converted and stored in a memory in the control circuit 12.
Next, in step S3, the captured data is synthesized for each small block described with reference to FIG.
Next, in step S4, using the luminance data synthesized in step S3, a focus detection calculation is performed for each CCD line sensor corresponding to each of the AF areas 41 to 48 shown in FIG. A focusing area where the main subject exists is determined from the areas 41 to 48.
[0028]
Next, in step S5, the in-focus state of the in-focus area is confirmed. If not in focus, in step S6, the focusing lens 14 is driven based on the calculation result in step S4, and steps S1 to S4 are executed again.
On the other hand, in step S5, if it is in focus, the process proceeds to step S7.
In step S7, the subject colors in the AF areas 41 to 48 are detected as described above with reference to FIGS.
[0029]
Next, in step S8, the luminance data of each AF area 41 to 48 is acquired using the luminance data acquired in step S3.
Next, in step S9, the luminance data of each AF area 41 to 48 is corrected based on the color information obtained in step S7.
Next, in step S10, an exposure calculation is performed based on the obtained background brightness data, brightness data of the AF areas 41 to 48 subjected to color correction, and the focus area, and an aperture value and a shutter speed are determined.
[0030]
That is, the luminance data of each of the AF areas 41 to 48 corrected in step S9 is subjected to multi-pattern photometry (for example, see Japanese Patent Publication No. 4-5972) with an emphasis on the main subject luminance (luminance of the focusing area). Determine exposure control values (aperture value and shutter speed).
Finally, in step S11, shooting is performed with the aperture value and shutter speed obtained in step S10, and the series of operations is terminated.
[0031]
In the above-described camera, a color filter is arranged on the light receiving surface of the CCD line sensor of the sensor chips 33, 34, and 35 to detect the color data of the subject, and luminance data obtained by the CCD line sensor based on this color data is obtained. Since the correction is made, the color of the subject existing in the AF areas 41 to 48 can be reproduced easily and reliably.
[0032]
That is, in the above-described camera, the color filter is formed on the CCD line sensors of the sensor chips 33, 34, and 35, so that the color detection of the subject light can be performed simultaneously with the focus detection. Optical system and color metering element for each color, or extremely multi-segment photometric sensor 9 with R, G, B color filters attached to each metering area is not required, and the AF area or camera selected by the user is automatically The color of the subject existing in the selected AF area can be faithfully reproduced at low cost.
[0033]
In the above-described camera, since the exposure value is calculated based on the luminance data corrected by the color data of the CCD line sensor, it is possible to obtain exposure in consideration of the color of the subject.
In the above-described embodiment, the example in which the luminance data of the shooting screen G is detected by the CCD line sensor has been described. However, the present invention is not limited to this embodiment, and a photometric sensor may be provided separately. good.
[0034]
In this case, as shown in FIG. 1, the subject image formed on the screen 4 is measured by dividing the luminance of the subject into a plurality of areas including each AF area corresponding portion through the pentaprism 5 and the photometric lens 8. An image is formed on the photometric sensor 9.
In the above-described embodiment, the example in which the plurality of sensor chips 33, 34, and 35 are arranged in the focus detection unit 11 has been described. However, the present invention is not limited to this embodiment, and the focus detection unit includes a sensor. Only one chip may be arranged.
[0035]
In addition, the luminance data of the shooting screen G is detected by a separately provided photometric sensor (9 in FIG. 1), and when the luminance information is obtained by the CCD line sensor, the luminance information of the area excluding the AF area is detected by the photometric sensor. You may make it do.
FIG. 10 shows an example of a divided shape of the photometric sensor 9 with respect to the shooting screen G.
[0036]
This is divided into 61-65 photometry areas corresponding to the AF areas 41-48 shown in FIG. 3 and 66-70 photometry areas corresponding to the background.
FIG. 11 shows the spectral sensitivity characteristic of the photometric sensor 9 shown in FIG. 10, and it can be seen that the spectral sensitivity characteristic is biased near 550 nm. This spectral sensitivity characteristic is the same as the spectral sensitivity characteristic of a general camera photometric sensor.
[0037]
That is, since the spectral sensitivity characteristic of the photometric sensor 9 is biased to around 550 nm as shown in FIG. 11, an error occurs in the luminance data depending on the subject color. This error is corrected based on the color information.
[0038]
【The invention's effect】
As described above, in the camera of the first aspect, the color filter is arranged on the light receiving surface of the photoelectric conversion unit of the focus detection unit to detect the color information of the subject, and the luminance information of the photometry unit is obtained based on the color information. Since the correction is made, the color of the subject existing in the focus detection area can be easily and reliably reproduced.
[0039]
In the camera according to the second aspect, since the plurality of photoelectric conversion means are arranged corresponding to each of the plurality of areas set in the photographing screen defined by the photographing lens, the color of the subject can be more reliably reproduced. it can.
In the camera according to claim 3, since the exposure value is calculated based on the luminance information corrected by the color information of the photoelectric conversion means and the luminance information by the second photometry means, the color of the subject is more reliably reproduced. can do.
[0040]
In the camera according to the fourth aspect, since the luminance information for the area other than the focus detection area set in the photographing screen is detected by the second photometry means, the color of the subject can be more reliably reproduced. .
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a configuration of an embodiment of a camera of the present invention.
2 is an explanatory diagram showing a configuration of a multi-area focus detection unit in FIG. 1; FIG.
3 is an explanatory diagram showing an AF area of the camera of FIG. 1. FIG.
4 is an explanatory diagram showing an arrangement of CCD line sensors on the AF sensor of FIG. 2; FIG.
FIG. 5 is an explanatory diagram showing an enlarged view of portions A and B in FIG. 4;
6 is an explanatory diagram showing wavelength characteristics of a color filter on the AF sensor of FIG. 5. FIG.
FIG. 7 is a generally known xy chromaticity diagram.
FIG. 8 is an explanatory diagram showing a color area based on FIG. 7;
FIG. 9 is a flowchart showing the operation of the camera shown in FIG.
10 is an explanatory diagram showing an example of a divided shape of the photometric sensor of FIG. 1. FIG.
11 is an explanatory diagram showing spectral sensitivity characteristics of the photometric sensor of FIG.
[Explanation of symbols]
2 Photo lens 9 Photometric sensor (second photometric means)
11 Multi-Area Focus Detection Unit 12 Control Circuits 33, 34, 35 Sensor Chips 41 to 48 AF Areas 51 to 58 CCD Line Sensors 61 to 70 Photometric Area G Shooting Screen

Claims (4)

Comprising a photoelectric conversion means having a plurality of light receiving elements that receive light flux from the object through the camera lens, with a focus detection means for detecting a focusing state of the photographing lens based on the output of the photoelectric conversion unit camera In
A plurality of color filters are provided for each of the blocks obtained by dividing the plurality of light receiving elements for each of the plurality of light receiving elements
Photometric means for detecting luminance information of the subject based on outputs of the plurality of light receiving elements ;
A color detection means for detecting the color information of the object based on the output of each block of said light receiving elements receiving the light beam through the color filter,
Correction means for correcting an error of the luminance information due to the color of the subject based on the color information;
Exposure calculation means for calculating an exposure value for the subject based on the luminance information corrected by the correction means;
A camera characterized by comprising The camera of claim 1,
A plurality of photoelectric conversion means corresponding to each of a plurality of areas set in the shooting screen defined by the shooting lens;
The photometric means detects the luminance information for each of the plurality of regions based on outputs of the plurality of photoelectric conversion means;
The color detection unit detects the color information for each of the plurality of regions based on outputs of the plurality of photoelectric conversion units,
The correction means corrects the luminance information for each of the plurality of photoelectric conversion means,
The camera according to claim 1, wherein the exposure calculation means calculates the exposure value based on luminance information corrected for each of the plurality of photoelectric conversion means. The camera according to claim 1 or claim 2,
A second photometric means for detecting luminance information of the photographing screen;
The exposure calculation means calculates the exposure value based on the corrected luminance information and the luminance information obtained by the second photometry means. The camera according to claim 3.
The camera according to claim 2, wherein the second photometric means detects the luminance information for an area other than the focus detection area set in the photographing screen.

Images