JP3475473B2 - Camera photometer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photometric device for a camera for photometrically measuring a subject to obtain an appropriate exposure control value.

[0002]

2. Description of the Related Art A conventional photometric device, as shown in FIG.
Exposure control is performed by using a photometric element having a spectral sensitivity characteristic having a sensitivity peak near a wavelength of 550 nm.

[0003]

However, the photometric device having the spectral sensitivity characteristic as described above has the three primary colors R of light.
Since it has a peak of sensitivity in the green area of (red), G (green), and B (blue), even if an excellent exposure is given to an achromatic subject or a green subject, red, blue, etc. The sensitivity to these colors is low for subjects close to the primary colors of
You recognize it as a dark subject.

For this reason, when a subject having a large amount of red and blue components is photographed, it is overexposed as compared with the actual sensitivity of the color film. As a result, the photographed photograph becomes overexposed, and color reproducibility is improved. There is an inconvenience that a bad picture is taken.

For example, when a scene with a lot of red component such as an evening scene is photographed, the conventional photometric element has a low sensitivity to the red component, resulting in overexposure, and red reproducibility is poor during daytime. It becomes a picture of the scene.

Therefore, according to the present invention, even if an object having a large number of monochromatic colors such as red or blue is provided, without excessive exposure,
An object of the present invention is to provide a photometric device for a camera, which is excellent in reproducibility of each color.

[0007]

In order to solve the above-mentioned problems, the invention of claim 1 divides an object into a plurality of color components and performs photometry, and outputs a plurality of photometric values corresponding to the respective color components. Photometric means, detection means for detecting the magnitudes of the plurality of photometric values, selection means for selecting the largest photometric value among the magnitudes of the photometric values detected by the detection means, and the selection A photometric device for a camera, comprising: an exposure control unit that controls exposure using only the maximum photometric value selected by the unit. According to a second aspect of the invention, in the photometric device for a camera according to the first aspect, the photometric device divides into red, green and blue color components to perform photometry, and is a camera photometric device. According to a third aspect of the present invention, in the photometric device for a camera according to the first aspect, the photometric means performs division into the plurality of color components using a color filter. is there. The invention of claim 4 is the photometric device for a camera according to claim 1, wherein the photometric means divides the color components into a plurality of color components by using a dichroic mirror. is there.

[0008]

In the structure of the present invention, the photometric element divides the subject light into a plurality of, for example, the three primary colors R, G, B, and performs level detection for each color component. The exposure control means selects, for example, a plurality of weighted photometric values or only the maximum value of the photometric values from the photometric output of each color component measured by the photometric element.
Alternatively, the maximum value is mainly used as the exposure control value, and the aperture value and the shutter speed are calculated based on the exposure control value to perform the exposure control. Therefore, even if a scene with many single colors such as red and blue is photographed, a photograph with excellent color reproducibility can be obtained without being overexposed.

[0009]

1 is a block diagram showing an embodiment of a camera incorporating a photometric device according to the present invention. In the present embodiment, the light that has passed through the taking lens 1 is reflected by the reflecting mirror 2 and forms an image on the focusing screen 3, is observed by the photographer through the pentaprism 4 and the eyepiece lens 5, and the pentaprism 4 and An image is formed on the photometric element 7 through the photometric lens 6.

As shown in FIG. 2, the photometric element 7 is composed of a one-chip type color sensor using a stripe filter, and in this example, nine strip-shaped optical sensors 71R, 71G, 71B, 72R. , 72G, 72B, 7
Each of the 3R, 73G, and 73B has a configuration in which R, G, and B color filters are sequentially attached.

The spectral sensitivity characteristics of the optical sensors 71R to 73B are, as shown in FIG. 3, about 450 nm for the optical sensors 71B to 73B (B component), about 550 nm for the optical sensors 71G to 73G (G component), and the optical sensor 71R. .About.73R (R component) has a sensitivity peak near 650 nm. This spectral sensitivity characteristic may be determined according to the spectral sensitivity characteristic of a general film.

The photometric output of the photometric element 7 is output by each optical sensor 71R.
~73R, 71G~73G, is added to each 71B～73B, sent sensor data D _R of the R component, the sensor data D _G of the G component, the exposure control unit 8 as the sensor data D _B of the B component.

In the exposure control unit 8, the sensor data D _R ,
D _G, and the exposure control value D _O is calculated ones maximum level from among D _B, the exposure control is performed to determine an aperture value and a shutter speed based on the control value D _O.

In the present embodiment, for convenience of explanation, the case where the photometric element 7 is composed of a strip-shaped photosensor divided into nine parts has been described, but in practice, each color component of the incident light is described. It is divided into a large number of parts to capture information, and is installed in a position that is out of focus to some extent.

Next, the operation of the photometric device according to the present invention will be described with reference to the flow chart shown in FIG.
First, the sensor data D _R , D _G , D _B of each color component R, G, B from the photometric element 7 is loaded into the exposure control unit 8 (step S1).

Next, R component sensor data D _R and G
Compare the sensor data D _{G of the} component (step S
2) If the sensor data D _R is larger, then R
Component sensor data D _R and B component sensor data D
_B is compared (step S3). As a result, if the sensor data D _R is larger, the R component is the largest among the color components R, G, B.
_{Let R} be the exposure control value D _O (step S4).

When the G component sensor data D _G is equal to or larger than the R component sensor data D _R (step S
2) or when the B component sensor data D _B is equal to or larger than the R component sensor data D _R (step S
3) compares the sensor data D _B of the sensor data D _G and B component of the G component (step S5).

As a result, if the sensor data D _G is larger, the G component is the largest among the color components R, G, B, so the sensor data D _G is set as the exposure control value D _O (step S6). ). If the sensor data D _B is equal to or larger than the sensor data D _G , the sensor data D
_B is the exposure control value D _O (step S7).

FIG. 5 is a partial block diagram showing a second embodiment of the photometric device according to the present invention. In this embodiment, the light emitted from the penta prism 4 is converted into three photometric lenses 6R, 6G,
The light is collected by 6B, and is passed through each color filter of R filter 9R, G filter 9G, and B filter 9B installed behind each photometric lens 6R, 6G, 6B, and photometric elements 7R, 7G, 7B.
To measure light. The outputs of the photometric elements 7R, 7G and 7B are sent to the exposure control section 8 as sensor data D _R , D _G and D _B.

FIG. 6 is a partial block diagram showing a third embodiment of the photometric device according to the present invention. In this embodiment, the light emitted from the penta prism 4 is converted into the dichroic mirror 10.
Then, only the R component is passed through, the light is condensed by the photometric lens 6R, and the light is measured by the photometric element 7R. Next, of the G and B components reflected by the dichroic mirror 10, the B component passes through the next dichroic mirror 11, is focused by the photometric lens 6B, and is photometrically measured by the photometric element 7B. Finally, the G component reflected by the dichroic mirror 11 is the photometric lens 6G.
Then, the light is condensed by and is measured by the photometric element 7G. Photometric element 7
The outputs of R, 7G and 7B are sensor data D _R , D _G and D.
It is sent to the exposure control unit 8 as _B.

FIG. 8 is a flow chart for explaining a fourth embodiment of the photometric device for a camera according to the present invention. In addition,
Since the basic configuration of this embodiment is substantially the same as that of the first embodiment, the description thereof will be omitted and its operation will be mainly described with reference to FIG. In the present embodiment, the exposure control value is determined by using the weighting coefficient. In the exposure control unit 8,
Of the sensor data D _R , D _G , D _B of the respective color components R, G, B sent from the photometric element 7, the maximum color output Dmax, the intermediate color output Dmid, and the minimum color output The output Dmin is calculated (S101), and the outputs Dmax and Dmi are calculated.
d and Dmin respectively weighting coefficient k1,
The added value is calculated using k2 and k3 (S102),
The exposure control value D is determined. Note that the weighting factors k1 and k
For 2 and k3, various scenes are assumed and optimal values are set. The weighting coefficient k1 of Dmax is the other weighting coefficient k.
2, and greater than k3, the better the weighted maximum output Dmax, the heavy point manner. For example, in the case of a scene such as the setting sun, k1>k2> k3 can be set.

In each of the above-mentioned embodiments, the photometric element is divided into three colors of R, G and B. However, if the number of divisions is increased, more accurate photometry can be performed. Further, if the photometric device according to the present invention is applied to a multi-division photometric device that divides a screen into a plurality of parts to perform photometry, more accurate photometry can be performed.

[0023]

According to the present invention, a photometric element for dividing an object into a plurality of color components is provided, and photometric values corresponding to the respective color components, for example, a plurality of weighted photometric values or a plurality of photometric values are provided. Only the maximum value of these values is used, or the maximum value is used intensively for metering, so even in a scene with many single colors such as red and blue, color reproducibility can be achieved without overexposure. Excellent photometry is possible.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a photometric device for a camera according to the present invention.

FIG. 2 is a configuration diagram showing an embodiment of the photometric device shown in FIG.

FIG. 3 is a diagram showing spectral sensitivity characteristics of each color of the photometric element shown in FIG.

FIG. 4 is a flow chart for explaining the operation of the photometric device according to the present invention.

FIG. 5 is a partial configuration diagram showing a second embodiment of a photometric device for a camera according to the present invention.

FIG. 6 is a partial configuration diagram showing a third embodiment of a photometric device for a camera according to the present invention.

FIG. 7 is a diagram showing a spectral sensitivity characteristic of a conventional photometric element.

FIG. 8 is a flow chart for explaining a fourth embodiment of the photometric device for a camera according to the present invention.

[Explanation of symbols]

1 Photographing lens 2 Reflection mirror 3 Focusing screen 4 Penta prism 5 Eyepiece lens 6, 6R, 6G, 6B Photometric lens 7, 7R, 7G, 7B Photometric element 8 Exposure control section 9R, 9G, 9B Color filter 10, 11 Dichroic mirror 71R -73R, 71G-73G, 71B-73B Optical sensor

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Claims (4)

(57) [Claims] 1. A photometric unit that divides an object into a plurality of color components to perform photometry, and outputs a plurality of photometric values corresponding to the respective color components; and a detection unit that detects the magnitude of the plurality of photometric values. Exposure control is performed by using only a selection unit that selects the maximum photometric value among the photometric values detected by the detection unit and only the maximum photometric value selected by the selection unit. A photometric device for a camera, comprising: exposure control means. 2. The photometric device for a camera according to claim 1 , wherein the photometric means divides into red, green, and blue color components for photometry. 3. The camera photometric device according to claim 1 , wherein the photometric unit divides the color components into a plurality of color components using a color filter. 4. The photometric device for a camera according to claim 1 , wherein the photometric means performs division into the plurality of color components using a dichroic mirror.