JPH023532Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a photometry device for a camera that measures light by dividing a photographic screen into a plurality of areas.

For example, Japanese Patent Application Laid-Open No. 114918/1984 discloses a multi-photometering device that classifies the screen based on the divided photometry output of the photographic screen and generates appropriate exposure information output according to the result. In addition, Japanese Patent Application Laid-Open No. 57-42026
A multi-photometering device is disclosed that detects the maximum brightness of a photographic screen from the divided photometry outputs of the photographic screen, and generates appropriate exposure information output by comparing the maximum brightness with a predetermined reference value.

As described above, a photometry system suitable for a photometer that generates appropriate exposure information by metering the shooting screen separately was developed by Jitsukasho.
No. 55-125623. This photometric system will be explained below with reference to FIGS. 1 to 3.

FIG. 1 is a sectional view of the photometric optical system of a single-lens reflex camera. Light from an object passes through a photographic lens 1, is reflected by a mirror 2, and forms an image on a focus plate 3. This subject image is captured by condenser lens 4,
The light is measured by a photoelectric device 8 via a pentagonal roof prism 5, a triangular prism 6, and an imaging means (for example, an imaging lens) 7. Figure 2 shows a conventional shooting screen with a multiple division pattern of photometry areas, with a circular photometry area P ₅
is placed in the center of the screen, and the surrounding photometric areas P ₁ , P ₂ ,
P ₃ and P ₄ have the same shape and are arranged around the periphery.

Figure 3 shows the photographic lens 1, mirror 2, and
A pair of photoelectric devices 8L, assuming that they are formed by an imaging lens 7, are formed through an optical system of a reticle 3, a condenser lens 4, and a penta-roof prism 5.
A composite image 10 of the divided light-receiving portions of the 8R light-receiving surface is shown. That is, this composite image is an erect image that can be seen from the viewfinder, and the shared photometry areas of the plurality of divided light-receiving portions of the light-receiving surface of the photoelectric device coincide with the plurality of divided areas of the photographing screen 9. Only the central photometry area _P5 of the photographic screen is photometered in an overlapping manner by the light receiving portions of each photoelectric device. In FIG. 3, 7L and 7R are imaging lenses arranged on both the left and right sides of an eyepiece (not shown). Photoelectric devices 8L and 8R are arranged at focal positions of the imaging lenses 7L and 7R. Therefore, the light-receiving portion P ₃ ′ of the light-receiving surface of one photoelectric device 8L,
P ₅ ' and P ₁ ' are inverted by the imaging lens 7L and become photometric areas P ₁ , P ₅ , and P ₃ in the left half of the composite image 10.
The light-receiving portion P ₄ ′ of the light-receiving surface of the other photoelectric device 8R,
P ₅ ' and P ₂ ' are inverted by the imaging lens 7R and become photometric areas P ₂ , P ₅ , and P ₄ in the right half of the composite image 10.
The mutually corresponding light-receiving portions of each light-receiving surface of both photoelectric devices are symmetrically identical in shape. The quarter points of a straight line AB on the composite image plane passing through the center C of the circular area _P5 of the composite image 10 and perpendicular to the optical axis are designated as A, C, and B, respectively. The optical axis of the imaging lens 7L is the quarter point A of the composite image.
If the imaging lenses 7L and 7R are arranged so that the optical axis of the imaging lens 7R passes through the quarter point B of the composite image, the composite image 10 will have less distortion, and the left and right sides can have exactly the same shape. can.

Incidentally, such a photometry system can also be used for direct photometry in which an image reflected on a film surface or shutter curtain is directly measured.

In this type of photometry system, if the split photometry area _of the shooting screen 9 is divided into a split pattern as shown in FIG. As the proportion of prisms and microprisms increases, the amount of correction for the open F-number varies from lens to lens, and the amount of correction is larger than in conventional photometry systems, resulting in a larger margin of error. To solve this problem, it is necessary to widen the central photometry area. However, in order to widen the photometric area at the center, the area at the periphery becomes narrower and the function or accuracy of divided photometry decreases, so it is not possible to easily increase the area of the photometric area at the center.

Also, when switching from split metering to center partial metering using the central metering area _P5 , the central metering area is too central to the subject and the metering is biased towards the top and bottom of the shooting screen. For example, when shooting a subject that includes the sky, it is inevitably affected by the high brightness of the sky, resulting in an underexposed photo, especially when the main subject is on the ground side. .

The main purpose of the present invention is to provide a photometry device that uses at least two photoelectric devices to meter a photographic screen partially overlappingly, so that each divided photometry area can be divided into a portion of another divided photometry area without being substantially changed. Another object of the present invention is to provide a photometry device that can provide information on the brightness of all objects to the photometry output of the overlapping photometry area.

A further object of the present invention is to provide a photometric device as described above, which can provide information on the brightness of a subject on the ground side of the photographic screen to the photometric output of a divided photometric area near the center of the screen. It is.

In order to achieve the above object, the present invention includes first and second image forming means, a first photoelectric device for photometering a subject image formed by the first image forming means, and an image formed by the second image forming means. a second photoelectric device for photometering a subject image; the light receiving surfaces of the first and second photoelectric devices are each divided into a plurality of light receiving portions;
Each of the second photoelectric devices has a structure including a light-receiving portion consisting of a first light-receiving surface corresponding to photometry areas that overlap with each other on the photographing screen and a second light-receiving surface corresponding to mutually independent photometry areas. ing. This first light-receiving surface can be set according to the area on the screen where you want to perform redundant metering, and the second light-receiving surface can be set according to which area of the subject you want to capture brightness information in the redundant metering area. .

FIG. 4 shows a division pattern of the photometry area of the photographic screen when the overlapping photometry area is shifted from the center of the photographic screen to the ground side.

The parts corresponding to the peripheral photometric areas P ₁ , P ₂ , P ₃ , and P ₄ in Figure 2, which shows the conventional division pattern, are shown in Figure 4.
Q ₁ , Q ₂ , Q ₃ , and Q ₄ , and the portion corresponding to the central photometric area P ₅ is Q ₅ . In Fig. 2, a part of the top side of the circular photometric area P ₅ is removed, and the peripheral photometric area P ₃ ,
The shape of _Q5 is obtained by adding the area near the center of _P4 to the circular part _P5 . If you do this,
The central photometry area has a non-circular shape, with the top side partially shaved off and the bottom side widened, so the influence of the split prism or microprism in the center of the finder screen is reduced, and the central photometry area in split photometry is The aperture photometry error can be reduced.

In addition, if you switch from split metering to center metering that uses the center metering area, for example, when photographing a subject that includes the sky, you will be less affected by the brightness of the sky, and if the main subject is present. The ground side becomes the main metering area, allowing you to take proper photos.

FIG. 5 shows the shape of each light-receiving portion of the light-receiving surface of two photoelectric devices that perform shared photometry on the area on the photographic screen in FIG. 4 when the overlapping photometry area is shifted from the center of the photographic screen to the ground side.

In FIG. 5a, the light-receiving surface of the left optoelectronic device is divided into mutually insulated light-receiving parts Q ₁ ', Q ₃ ', Q _5L '.

In FIG. 5b, the light-receiving surface of the right optoelectronic device is divided into mutually insulated light-receiving portions Q ₂ ′, Q ₄ ′, Q _5R ′. The mutually corresponding light-receiving portions Q ₁ ′, Q ₂ ′, Q ₃ ′, and Q ₄ ′ of the light-receiving surfaces of both photoelectric devices have the same shape and have mutually independent photometry areas. Light receiving part Q _5L ′,
Although Q _5R ′ is symmetrical in shape, it has photometric regions that overlap with each other.

When the light-receiving parts of the light-receiving surfaces of each photoelectric device shown in Fig. 5a and b are superimposed, the light-receiving part becomes as shown in Fig. 5c.
Q _5L ′ and Q _5R ′ have the same shape as the photometric area of Q ₅ in FIG. 4.

In other words, the pattern of the light-receiving part is created by widening the area of the ground-side part of the center part on the opposite side of the respective assigned areas of the light-receiving part of the left and right photoelectric devices in order to widen the area of the ground-side part of the center part. The device is characterized in that an area equal to the central area Q ₅ of the photographic screen in FIG. 4 is obtained by overlapping the left and right central areas of the light receiving portions Q ₃ ' and Q ₄ ' of the device without narrowing the area. In other words, the outputs of the light-receiving parts Q ₃ ′ and Q ₄ ′ are obtained from the photometry areas P ₃ and P ₄ of the photographic screen in Fig. 2,
The outputs of the light-receiving portions Q _5R ′ and Q _5L ′ are obtained from the photometry area Q ₅ of the photographic screen shown in FIG. 4 by electrical processing such as adding these and calculating an average value. still,
The number of light-receiving surfaces corresponding to each divided photometry area does not need to be one, and a large number of light-receiving surfaces may be provided using a CCD two-dimensional image sensor or the like.

In the above embodiment, Q _5L ' is the first light receiving surface, Q ₃ ' is the second light receiving surface, Q _5R ' is the third light receiving surface, and Q ₄ ' is the fourth light receiving surface. It consists of

According to the present invention, it is possible to obtain a photometric device that enlarges the photometric area of the central divided photometric area of the photographing screen without narrowing the photometric area of the peripheral divided photometric areas.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the photometric optical system of a single-lens reflex camera, Figure 2 is a photographic screen with a conventional division pattern of photometric areas, and Figure 3 is a diagram of a pair of photoelectric devices projected through an imaging lens. The composite image, Fig. 4, shows a photographic screen having the division pattern of the photometric area of the present invention, and Fig. 5 shows the shape of the light-receiving part of the light-receiving surface of a photoelectric device that performs photometry in each of the divided photometric areas on the photographic screen of Fig. 4. ,
A shows the shape of the left photoelectric device, b shows the shape of the right photoelectric device, and c shows the shape of the light receiving portions of both photoelectric devices superimposed. Explanation of symbols of main parts, 7L, 7R...imaging lens, 8L, 8R...photoelectric device, Q ₁ ′, Q ₃ ′, Q ₂ ′,
Q ₄ ′... mutually independent light receiving parts, Q _5L ′, Q _5R ′...
Light-receiving areas that overlap each other.

Claims (1)

[Claims for Utility Model Registration] 1. First and second imaging means, a first photoelectric device that measures the light of a photographic screen via the first imaging means, and the second imaging means. a second photoelectric device that measures light on the photographic screen through the camera; , a second light-receiving surface that photometers a region located around the center region, and the second photoelectric device has a third light-receiving surface that photometers a region near the center; a fourth light-receiving surface that is independent from the light-receiving surface, is located around the area near the center, and measures a different area from the area that is photometered by the second light-receiving surface; The light-receiving surface simultaneously measures at least a part of the area that the fourth light-receiving surface measures in addition to the area near the center, and the third light-receiving surface measures the second light-receiving surface in addition to the area near the center. 1. A photometry device for a camera, characterized in that the shape of a light receiving surface is determined so that at least a part of an area to be photometered by the surface is photometered at the same time. 2 Utility Model Registration In the photometering device according to claim 1, an area where the first and third light-receiving surfaces measure light in addition to the area near the center is located on the ground side of the photographing screen. A photometric device featuring: