How to adjust the white balance when the camera is shooting? What does white balance do?

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Analysis:

white balance adjustment

In TV shooting, white balance adjustment is the main method to control the tone of the picture. What is white balance? When shooting a white object to get a white image, that is, when shooting a white object, the red, green and blue signals output by the camera are equal, which is called white balance. White balance is a technical state of the camera. It used to be thought that the camera could only shoot in a white balance state, which was very one-sided. The purpose of adjusting the white balance is not only to make the camera in a white balance state, but also to destroy the white balance of the camera by adjusting the black-and-white balance, so as to achieve the purpose of subjective color cast. There are three steps to adjust the black-and-white balance: first, choose the appropriate color filter (coarse adjustment); Second, check whether the aperture is in the automatic position, and select A or B (not P) with the white balance button; Third, aim at a piece of white paper or other white objects, move the white switch, and wait for the video recorder to appear OK! (white balance completed), and then adjust the black balance. If the black balance is not adjusted, the dark part of the picture will have a color cast and the contrast will be weakened. Black and white balance adjustment is the main method to control the color tone of the picture. Adjusting the balance between black and white is a technical skill and a creative means. Different whitening methods can get different tone effects.

White paper is needed to correctly adjust the color of the scene. There are different shades of white paper, such as green copy paper and yellow white newspaper. Different shades have different effects on the tone of the picture. The rule is that the chromaticity of white paper and the chromaticity of the picture are complementary colors.

Balance with yellow and white paper and the picture will be blue.

After the chromaticity of white paper is determined, it can't be changed at will in the same scene, let alone find a white object to adjust the white, otherwise the color of the picture will not be uniform.

In addition to the choice of white paper, the direction of white paper is also very important. For example, when the exterior is white, it should be placed at a 90-degree angle with the sun, so that the white paper can illuminate some skylight. If the white paper is white to the sun, then the shadow in the picture will be blue. Ambient colors have a great influence on white tones, such as shooting indoors, where the red carpet is laid. To consider the influence of carpet on the tone of the picture, deliberately let the white paper reflect some reflected light from the red carpet, so that the picture will not be blue (the complementary color of red is blue).

If the picture is deliberately biased, you can choose light-colored paper to turn it into white, and white with light yellow tone can make the picture appear blue tone, which is a common method to shoot night scenes. On the contrary, choose blue-green paper to balance white, and you can get warm tones. However, it should be emphasized that you can't use saturated paper or objects for whitening, which will damage the whitening circuit of the machine. Generally, white balance chromatography is used to adjust white.

In short, when using white balance to control the picture color, we should always pay attention to the chromaticity (whiteness) of white paper and the chromaticity (color temperature index) of light shining on white paper.