JPH0629938B2 - Color balance adjuster - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an apparatus capable of arbitrarily and easily correcting the color balance of a copying object in a copying machine or printer using a color photosensitive material.

[Prior Art] When performing color photography through a lens, adjusting the color balance to reproduce a color that is close to the truth, or conversely, emphasizing a certain color to give an artificial taste. Is being attempted. To meet this purpose, there are methods of changing the illumination light and placing a color filter in front of the lens. A more effective method is to place a color filter at the iris diaphragm position of the lens, and as a practical example of that, there is a colorless transparent portion and a C (cyan) filter as shown in FIG. A flat glass that distinguishes the pasted part at the center, a colorless transparent part and M
(Magenta) Flat glass that distinguishes the part where the filter is attached and flat glass that distinguishes the colorless and transparent part and the part where the Y (yellow) filter is attached at the center are arranged parallel to the position of the iris diaphragm of the lens. In some cases, the contribution ratio of each filter is changed by moving each filter in a direction orthogonal to the center division line.

[Problems to be solved by the invention]

As described above, even in the conventional effective color balance adjustment method, as shown in FIG. 6, there may be a part where two filters overlap, a part where only one filter exists, and in some cases, a part where three kinds of filters overlap. Since the transmittance partially changed in the same iris diaphragm zone, proper exposure could not be maintained without light amount correction. Then, even if three filters having the same filter multiples are used, it is necessary to calculate the light amount in consideration of the extinction of the overlapping portion, which makes it very difficult to correct the light amount. Furthermore, the mechanism of the apparatus of this system has to be complicated and large because the three filters are independently moved as shown in FIG.

An object of the present invention is to provide a color balance adjusting device that can obtain an accurate color balance and a desired color balance with a simple structure and operation without correcting the light amount.

[Means for solving problems]

 This object is solved by the following technical means.

Absorption or transmission characteristics corresponding to the spectral sensitivity of the light-sensitive material at approximately the iris diaphragm position of the projection lens of the exposure optical system (in the plane between the front principal point and the rear principal point, or in the vicinity thereof, in a plane substantially perpendicular to the optical axis) And a filter unit in which a plurality of color filters having mutually equal filter multiples are radially arranged from the center in a plane-divided type, and the filter unit can be moved to any position in a plane substantially perpendicular to the optical axis. A color balance adjusting device characterized in that

[Examples and functions]

An embodiment of the present invention will be described with reference to the sectional view of FIG. 1, the perspective view of FIG. 2 and the schematic functional diagram of the surface dividing filter of FIG.

In the lens barrel bracket 1, the front lens group 6 and 6'are fixed by the spacer 4'and the tightening ring 4, and the front lens group portion 2 and the rear lens group 7, 7'are fixed by the tightening ring 5. It is composed of a slide guide portion 13 into which the group lens barrel portion 3 and the filter unit 12 are fitted and movable. The filter unit 12 has an opening 15 with a front principal point surface.
And the intermediate portion of the opening 16 having the rear principal point surface, that is, the position of the iris diaphragm. Further, although the aperture 16 has a diaphragm adjusting mechanism, it is omitted in FIG.

Also, as shown in FIG. 4, if the principal point has an object on the front principal point surface, the image can be formed on the rear principal point surface in the same direction and size, and the object can be entered toward the front principal point. Since there is a property that the reflected rays are emitted from the rear principal point without changing the direction, at the position between the two principal points, that is, at the position of the iris diaphragm, the predetermined distance of the subject passing through this diaphragm aperture is set. Only the brightness (amount of light) of the light for forming an image at a position is adjusted by the size of the opening, and the image is not shaded.

Since the light of each part of the subject passes through almost the entire area of the opening, for example, as shown in Fig. 3, for example, a cyan maximum filter, a magenta maximum filter, and a yellow maximum filter are transmitted. Each of the filters is made into an equal filter multiple, and they are brought into contact with each other. For example, a glass plate having a shape close to a square is attached to the center of the glass plate in equal divisions, and the division center 0 is the center of the opening 15. When placed in a position that coincides with the above, the respective cyan, magenta, and yellow filter areas become equal in amount, which is an effect when a normal neutral finish is desired.
However, when it is desired to emphasize cyan and yellow and weaken magenta, for example, the division center 0 of the filter 8 is moved horizontally x and vertically y to move it to 0 '.
The purpose can be achieved by positioning the filter as 8 '.

The amount of movement of x and y depends on the degree of color balance adjustment, and the relationship between the degree of color balance and the amount of x and y is determined by experiment. Based on the result of the experiment, it is possible to obtain a desired color balance by moving it to a predetermined position.

The movement is the y-direction slider 11 of the filter unit 12.
Is fitted into the slide guide portion 13 of the lens barrel bracket 1 to achieve movement in the y direction, and the y direction slider
A filter frame 9 having a filter 8 mounted on 11 is fitted on the slide surface 10 in the x direction of the slider 11 in the y direction.
It moves in the x direction (direction perpendicular to the plane of the paper in FIG. 1) while being held by the end face of the opening 15. The driving means for the movement is
A screw, a rack and a pinion, a wire and a pulley can be used, but they are omitted in the figure.

The base point and the moving scale in the xy direction are engraved on the lens barrel bracket, slide 11 and filter frame, and if the display corresponding to each color balance is made clear, it is very easy to reproduce the required color balance. Like

It should be noted that the three-division filter is a simple and accurate method in which three types of filters are attached to each other on a colorless and transparent flat glass plate.

As the filter, a three-division filter having an equal filter multiple of cyan, magenta, and yellow was used as an example, but a plurality of two or more division filters can be used according to the application.

Furthermore, it is desirable to put the filter in the space between both principal points, but if space is not convenient, place it in a space as close to the principal point as possible and choose a position with less image vignetting for practical use. It may not matter.

The filter may have the maximum transmission characteristic for each color, or may have the maximum absorption characteristic, and may be used depending on the purpose.

〔The invention's effect〕

According to the present invention, the required color balance is accurately calculated by a simple operation with a much simpler mechanism as compared with the conventional apparatus in which several thick filters are stacked and each filter position is calculated to obtain the required color balance. It has become possible to specify the color, and it is possible to achieve great effects in expressing color reproduction and special color effects.

[Brief description of drawings]

FIG. 1 is an overall sectional view of an embodiment of the present invention, FIG. 2 is a perspective view of a part thereof, and FIG. 3 is a functional diagram of a surface division filter,
FIG. 4 is an explanatory view of the characteristics of the principal points, FIG. 5 is a schematic view of a conventional color balance filter in the position between principal points, and FIG. 6 is a light quantity distribution diagram of the color balance filter viewed from the optical axis direction. 1 ... Lens barrel bracket 2 ... Front lens barrel portion 3 ... Rear lens barrel portion 6, 6 '... Front lens group 7, 7' ... Rear lens group 8, 8 '... Filter 9 ... … Filter frame 10 …… Sliding surface in x direction 11 …… Slider in y direction 12 …… Filter unit 13 …… Slide guide part 14 …… Optical axis 15,16 …… Opening part 17 …… Mounting stand for lens barrel unit

Claims (1)

[Claims] 1. Corresponding to the spectral sensitivity of a light-sensitive material at approximately the position of the iris diaphragm of the projection lens of the exposure optical system (in the plane between the front principal point and the rear principal point or in the vicinity thereof, at a plane substantially perpendicular to the optical axis). A filter unit in which a plurality of color filters having absorption or transmission characteristics and having equal filter multiples to each other are radially arranged from the center in a plane-divided type is provided, and the filter unit is arranged in an arbitrary plane in a plane substantially perpendicular to the optical axis. A color balance adjusting device characterized by being movable to a position.