The purpose of the filter

Remove dust

In nature, the atmosphere is filled with a lot of very fine dust and water vapor, the formation of dust.Sun in blue, violet light line through the dust, was a large amount of scattering, blurs the distant scenery to produce a hazy state.The greater the distance the more far, the degree of fuzzy.In this case, such as the distant scenery, due to the film of dust in the diffusion of blue, and purple line is extremely sensitive, photograph of a distant scene image is not clear.

In order to make the distant scenery can achieve the image is clear, will need to choose to absorb and less blue, violet light filter.In general, colour and lustre is deep yellow, orange, or red filter, can absorb dust blue, violet light scattering by a line, the distant scenery get a clear image.

Adjust the contrast

Because of plates on the spectrum of light color performance each have differences, objects of different colors, black and white ash after the exposure is embodied in the photograph tone shades each are not identical, characterized by lack of contrast or contrast is too strong.In photography, sometimes to a portion of the scene color to adjust, the niche it tone will be reflected in the photograph more or less, you need to choose appropriate color filter to enhance or reduce the amount of this part of the light through.This is a filter to adjust contrast USE

Taken in winter with the blue sky, green pine snow, Snow White and the blue sky, green trees and contrast is very wide, such as with a light green color, contrast is more humorous effect can be obtained.If use panchromatic film shooting in yellow objects of the scarlet letter, through the yellow light green color filter, can make the yellow bright, black the scarlet letter, the handwriting is very outstanding.On the other hand, such as added with red, orange, and yellow light can through the red filter, weakens the contrast, the yellow, red two colors are in light grey, the handwriting is not obvious.Shooting portraits in the sun, in order to adjust the face brightness and sky brightness contrast, yellow color filter is often used to obtain normal tone.

Performance yun

Photography in outdoor activities, mostly relies on the sky.The blue sky and white clouds, or the bright clouds often make a scenery added color photographs;In daily photos to commemorate, people also like to use "white clouds floating in the blue sky in the background.

In order to show the blue sky white clouds, yellow color filter can also be used, it has absorption effect to the light of blue sky and white clouds, but in the blue sky blue, violet light absorption to stop more, on the photos show the deep dark gray tone;For white cloud of light absorption is less, the white clouds in the sky of dark grey in the picture.

If add orange and red color filter in a way that shows the sky, can make more dark blue sky, white clouds more outstanding, but often give a person a kind of unnatural distortion.So in general, unfavorable use blue sky white clouds, red, orange color filter performance unless it is to create a special artistic effect.

To eliminate the color

When shooting colored objects, such as the need to eliminate or reduce one kind of color, can choose the same as the color filter, make to weed out the color of a large number of pass, on the photo is shown as white, have played an important role in eliminating.Such as items in the contaminated by a certain color, want to eliminate the color of the pollution, and the color the same filter can also be used to obtain satisfactory results.

Correction color

Sometimes with black and white film shot in lighting conditions, because the lights in the light too much red, yellow, orange, blue, purple light is too little, can according to need to add a blue filter to absorb too much light red, orange, relatively made up for the inadequacy of blue and purple light.When filming safflower greenery, red filter, just leaves dark;Add green filter, the dark Ye Ming flower.

In color photography, to make the furniture of all sorts of color can achieve color balance on color plates, often choose color correction effect correction color filter.

Special effects

Used in outdoor, strong sunlight panchromatic film with scarlet color filter, can obtain the effect of the moon;Such as the red filter and polarizer used together, can further strengthen the night scene atmosphere.When shooting on location in the movie, commonly used this method to create outdoor night effect.

Reduce the brightness

In some light and clear the environment, such as beach, such as snow, desert places, although exposure has reached the limit (namely aperture has been contracting to a minimum level, as for the shutter speed, one of the fastest, the speed is fixed on the film photography), still can't do moderate exposure, exposure combination in order to adapt the brightness of the scenery, will need to choose neutral grey filter can reduce brightness, the scenery of this degree is generally lower, can adapt to the exposure to the brightness.Sometimes in order to reduce the sky or the brightness of the background section, often use half a neutral grey filter to local decrease brightness, intensity of the ground scene is constant.The lower the brightness of the neutral grey filter is indispensable in the movie photography.