JPS5987438A - Photometric device for automatic exposure - Google Patents

Abstract

PURPOSE:To determine more correct exposure by using both information from a photometer measuring the reflected light intensity of a subject and photometers measuring light intensity in the directions making a fixed angle with the direction of the subject to control exposure. CONSTITUTION:A camera 1 having a photometer consisting of five point photometers making right angles each other is provided with a photometer 3 measuring light intensity from the subject 2 and four photometers 4-7 receiving and measuring the light from the side making right angles with the subject 2 and measuring light rays from the directions I -IV. An operation part built in the camera 1 processes information from these plural photometers 4-7 to determine proper exposure and control precise exposure. Thus, the position of the camera 1, the position of the subject 2 and the intensity of sunlight can be decided by signals from the five photometers.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an automatic exposure mechanism of a camera, and more particularly to an automatic exposure metering device for photographing a subject at a proper exposure.

Conventional configurations and their problems With the development of semiconductor integrated circuits, automation is progressing in cameras as well. For example, the exposure value setting is 7.
A photocell (hereinafter abbreviated as SP) measures the intensity of the reflected light from the temporary object, and according to that value, the object information is processed by the calculation unit to determine the photographic speed and exposure time. The trouble of setting can be saved depending on the light intensity. As for automatic focusing, methods have been put into practical use that emit ultrasonic waves or infrared rays and measure distance based on the reflection time from the subject.

Furthermore, in the field of small cameras, efforts are being made to save labor and automate things such as setting film sensitivity, winding and unwinding the film, and automating flash photography, making it easy for anyone to take properly exposed photos anytime, anywhere. became.

However, these automations are not sufficient in all respects, and although there are no problems with snap-knob photos in many cases, in some cases the desired photos may not be obtained. For example, when photographing against the light or photographing a subject through a glass window, the dl, exposure, and distance settings may become unintended values.

Before the advent of automatic exposure mechanisms, exposure was determined at 71:1. Even now, professional photographers and some enthusiasts decide on exposure after measuring the light using a drop meter. There are two types of exposure meters: (1) a method that measures the light intensity reaching the subject from the light source, and (2) a method that measures the light intensity that reflects from the subject and reaches the camera. This also measures the light intensity at one point (spot photometry).

On the other hand, most automatic exposure mechanisms determine exposure by integrating the reflected light from the subject that reaches the camera over a certain area (angle). For example, CANONAE-1 (product name)
As seen in , there is center-weighted average metering. At this time, the exposure setting conditions will differ depending on which part of the film surface is to be photometered.

OBJECTS OF THE INVENTION The present invention has been made to address such problems in automation, and particularly to provide a photometer for automatic exposure that can obtain even more appropriate exposure.

Structure of the Invention According to the present invention (d), the intensity of a plurality of lights reaching the camera from different directions from the subject are measured separately, and the appropriate exposure value of the subject is determined from the plurality of spot exposure values. The explanatory diagram of the second embodiment is a schematic diagram of a camera having a photometer composed of five point photometers forming perpendicular angles to each other. This camera 1 is equipped with a photometer 3 for estimating the light intensity from the subject 2, and four photometers 4 for receiving and measuring light from the side forming an angle perpendicular to the subject 2. and measure the light from directions 1 to 1, respectively. Then, the information from these plurality of photometers 4 to 7 is processed by a calculation section provided in the camera 1 to determine the appropriate exposure and accurately control the exposure.

In this way, the position of the camera 1, the position of the subject 2, the intensity of sunlight, etc. can be determined by the signals of these five photometers.

For example, when the subject is backlit, only the subject intensity becomes relatively weaker than when the subject is normally frontlit. Examples according to the present invention will be shown below.

The examples shown here are lateral i, II, III, IV
25% of the maximum value of the intensity of the incident light (the standard object is 26% of the incident light
It is an average of the intensity of the subject (reflected) and the intensity of the subject. In this example, when E is retrograde and the sun is the object F, the judgment value is superior to that of the conventional example. In this example, 25% of the maximum value of the lateral intensity and the average of the subject intensity are used, but it is not necessary to limit the processing to only this.

The configuration of the present invention does not conflict with the conventional single-lens reflex camera's method of determining exposure using weighted integrals on the film surface, but rather complements it, so it is possible to have both in one camera. It is. It can be used as a simple exposure meter using only the photometer of the subject.

Effects of the Invention As described above, according to the present invention, it is possible to automatically determine a more appropriate exposure even when photographing in a situation where conventionally a person had to correct the automatic exposure value.

[Brief explanation of drawings]

The figure is a diagram showing a photometry state of a camera in an embodiment of the present invention. 1...Camera, 2...Subject, 3-7...
...Photometer.

Claims (1)

[Claims] (1) It has a first photometer that measures the reflected light intensity of the object, and a second photometer that measures the light intensity in a direction that makes a certain angle with the direction of the object, and the light intensity from these plurality of photometers is The automatic exposure photometer according to claim 1, characterized in that the exposure is controlled using information.