JP2000162674A - Standard gray light diffused plate and exposure deciding method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize exposure decision which cannot be realized in the conventional method such as transmitted light measurement and reflected light measurement by one plate, to directly obtain exposure to be corrected according to the brightness of a subject at the rear of a light diffused plate in the reflected light measurement, to realize stricter exposure measurement without correcting the exposure after the measurement, for bringing an auxiliary reflector into contact with the back surface of the light diffused plate and to adjust reflectance and a color tone by the auxiliary reflector. SOLUTION: Both of transmissivity and reflectance of a standard gray light diffused plate to be produced are adjusted to about 18 to 20%. When the reflected light is measured, the light diffused plate 3 is used to obtain the measured value corrected according to the brightness of the subject 4 at the rear of the plate 3, and when the plate 3 is used dedicatedly as the reflector, the auxiliary reflector is brought into contact with the back surface of the plate 3 and then used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure judging method at the time of photographing.

[0002]

2. Description of the Related Art Conventionally, there is an 18% gray reflective plate, a light diffusion plate for proper exposure determination by the same applicant, and an exposure determination method (image quality control method; Japanese Patent No. 2542495).

[Problems to be solved by the invention]

[0003] The prior art 18% gray reflector is limited to reflected light measurement and cannot determine proper exposure to a transmissive object.
On the other hand, one of the light-diffusing plates for judging proper exposure could only measure transmitted light.

In a reflection plate measurement, for example, a subject mainly composed of white tends to be overexposed, while a subject composed mainly of black tends to be underexposed. For strict photographing, exposure correction corresponding to each case is performed. There is a problem that it is necessary, and there is a problem that it is extremely difficult to give a strict reflectance and color tone as a reflector by a conventional method such as pigment coating and printing on cardboard, and fine adjustment after production cannot be performed. .

[0005] The present invention uses a single standard gray light diffuser plate,
The transmitted light allows for the determination of the proper exposure as a reference and the recording of the illumination light from the shooting light source, and when used on the subject, the measurement is corrected according to the brightness of the subject behind the diffuser. The purpose is to develop a standard gray light diffuser that can be used as a more precise reflector and a method for determining its exposure, while treating the measured value from which the value is obtained as a corrected value according to the brightness of the subject. .

[0006]

In order to achieve the object, according to the present invention, both the transmittance and the reflectance of the standard gray light diffuser are adjusted to be within a range of 18-20%, and a proper exposure which is a reference by the transmitted light. Judgment and recording of illumination light from a shooting light source, and when used on a subject as a reflector, the measured value that changes according to the brightness of the subject behind it can be treated as a stricter appropriate exposure .

In order to manufacture a strict reflector, an auxiliary reflector is adhered to the back surface of the reflector to achieve the object.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a light diffusing plate in which the transmittance of a synthetic resin is adjusted to about 18% with a pigment or the like is used as an exposure judgment standard and a color reproduction standard in photographing, and a reflected light measurement is performed. In this case, the reflected light measurement is performed in front of the subject to be photographed.

At this time, the diffuser has a reflectivity of about 18-
Since it is 20%, the appropriate exposure can be determined by reflection measurement as in the case of a normal standard reflector. However, the light coming from the diffusion plate due to the brightness of the object on the back surface of the light diffusion plate also involves transmitted light. Because of this, the measurements show only slight differences, which are within the range of proper exposure. The reason for this is that even if white or black is placed behind, only a change of about half a stop will occur, but in the present invention, it is possible to more strictly determine the appropriate exposure by actively utilizing the difference. I have to.

That is, for example, if white paper is placed on the back surface of the light diffusing plate, much light passing through the diffusing plate is reflected, so that a smaller exposure than the standard can be determined in the measurement. In many cases, it is desirable to provide the subject with this underexposure.

On the other hand, if black paper is placed on the back surface of the light diffusing plate, the exposure can be determined to be higher than the standard in the measurement. On the other hand, the subject mainly composed of black gives an underexposure to the standard. It is often desirable.

That is, it is possible to make an exposure determination in consideration of the brightness of a subject, that is, to give a very small exposure to a subject with a lot of white and give an exposure with a very little exposure to a subject with a lot of black. That's what it means.

Referring to FIG. 1, when the object 1 is photographed by the camera 1, when the standard gray light diffuser 3 is measured by a TTL camera or a single light meter in front of the object, the illumination from the light source 2 is obtained. The light is reflected in the camera direction at 3 and the meter is moved. At this time, a small exposure value can be read within a half aperture for a bright subject, and a large exposure value can be read within a half aperture for a dark subject. be able to.

Further, according to the present invention, an auxiliary reflecting plate is brought into close contact with the back surface of the diffusing plate to avoid the influence of the transmitted light from behind, and it is possible to use a more strict standard reflecting plate. That is, if a bright auxiliary reflector is applied to the back surface of the diffuser, the reflectance is high, and if a dark auxiliary reflector is provided, the reflectance can be lowered. The measured value of the proper exposure can be finely and strictly adjusted within the range of the half stop.

Further, the color tone can be finely adjusted by adjusting the color of the auxiliary reflecting plate to be adhered behind. In the above case, since the influence of the reflectance and the color tone of the auxiliary reflector becomes extremely weak in the reflection from behind, there is an advantage that the fine adjustment of the characteristics of the reflector, which has been very difficult so far, can be performed quite easily. In addition, an effect that has not been achieved in the related art can be obtained even as a method of manufacturing a reflector. FIG. 2 shows an embodiment of the present invention, in which an opaque holding plate 6 is used in close contact with the back surface of the diffusion plate 3, and the brightness and color tone of the holding plate 3 or a separate sheet having appropriate brightness and color is adjusted. The above problem is solved by adjusting the reflector to be more strict.

[0016]

As described above, the exposure obtained with the 18% reflector is a standard reference exposure. In the case of a photosensitive material having a high contrast or a CCD, the exposure is strictly determined according to the brightness of the subject. Correction is required. According to the present invention, there is an effect that the exposure correction value can be obtained within a half stop. By this, when the subject has a lot of white, the exposure is given conservatively, so that the so-called highlight of the subject can be prevented, and the subject has black. If the amount is large, the exposure is given rather large, so that the exposure that can prevent the so-called collapse of the shadow part can be determined,
It is possible to obtain an unprecedented effect that enables more precise texture rendering without the need to perform exposure correction according to the brightness of the subject as in the related art.

An opaque gray color on the back surface of the diffuser plate,
Black, white, etc. can be used to block the light coming from the back surface of the diffuser plate to prevent the influence of the incident light from the back surface, and the reflectivity of the diffuser plate can be high or low within a half stop. The reflector can be freely adjusted and a more precise exposure determination can be made.

Still further, the use of a color back can change the gray color tone, and can delicately control the color tone for a strict reflector.

When an auxiliary reflection plate is used on the back surface of the diffusion plate, the diffusion plate and the auxiliary reflection plate can be inserted into a frame-shaped frame so as to be detachable.

[0020]

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a case where an exposure determination is performed as a reflection / transmission plate at the time of photographing a subject.

FIG. 2 shows an embodiment in which an opaque holding plate is used as a reflection plate on the back surface of a diffusion plate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Silver halide or digital camera 2 ... Photographing light source 3 ... Diffusion plate which becomes this invention 4 ... Subject 5 ... Photographing stand 6 ... Holder plate 7 ... 3 and 6 Openable and closable tape

Claims (1)

[Claims] 1. The standard gray light diffuser made of synthetic resin has a transmittance and a reflectivity of 18-20% both inside and outside so as to be able to measure transmitted light and reflected light. It is possible to determine the exposure to be corrected according to the brightness of the object behind the diffusion plate, and to attach an auxiliary reflection plate for preventing light from being incident on the back surface of the diffusion plate on the back surface of the diffusion plate. A standard gray light diffusing plate and an exposure judging method, wherein light and darkness and color tone are adjusted to enable fine adjustment of the reflectance and color tone of the light diffusing plate.