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What are interference filters?

1. What is filter?
Optical filters, as the name suggests, are lenses that filter light. Also known as “polarizer”, it is a commonly used accessory in photography. It consists of two pieces of glass, with a layer of felt or similar material sandwiched between them, and through the transmission and reflection of light on the felt, the scene is changed in light and shade.

What are filters

2. The principle of filter
The filter is made of plastic or glass and added with special dyes. The red filter can only pass red light, and so on. The transmittance of the glass sheet is similar to that of air originally, and all colored light can pass through, so it is transparent, but after dyeing, the molecular structure changes, the refractive index also changes, and the passage of some light-shielding materials changes. For example, when a beam of white light passes through a blue filter, a beam of blue light is emitted, while very little green and red light is emitted, and most of it is absorbed by the filter.

3. The role of the filter
In photography, filters are used for a wide variety of subjects, such as landscapes, portraits, and still lifes. The following is a brief introduction to the function of the filter:
1)Control the contrast (i.e. light and dark contrast) of the picture by changing the angle of incident light to highlight the subject.
2) Use different color filters and lens chromatic aberration to adjust the color balance of the picture.
3) To achieve a specific artistic effect by choosing different color filters.
4) Adjust the aperture value or focal length as needed to obtain special effects.
5) Use as a protective mirror.
6) When the camera lens is dirty, it is used for cleaning.
7) Used as a teleconverter.
8) Used as a polarizer.

Post time: Sep-29-2022