What is the principle of polarizing plate in front of camera lens?

The principle is a filter, which filters out a part of polarized light.

After installing a polarizer, aim at the object to be photographed, rotate the previous lens, and you can clearly see the change in the viewfinder (except the paraxial). When you see that the reflection disappears completely, you can shoot. Exterior photography can make the blue sky bluer, with sharp contrast and saturated colors.

black and white and color photography can be used. It can effectively avoid the adverse effects of reflection on shooting. When shooting, you need to increase the exposure level by 2, which is a necessary filter for photographers. There are two kinds of polarizers. Linear polarizer (PL) and circular polarizer (CPL) have the same function.

Extended data:

Polarizer function

Polarizer has the function of shielding and transmitting incident light, which can make one of longitudinal light or transverse light transmit and the other shield. It is a composite material laminated by polarizing film, inner protective film, pressure-sensitive adhesive layer and outer protective film.

Polarizers are classified into black and white and color, and can be divided into transmission, transflection and reverse transmission according to applications. There are many kinds of artificial polarizers, one of which is made by using a polymer compound polyvinyl alcohol film with reticular structure as the substrate, then impregnating iodine with strong dichroism, reducing and stabilizing it with boric acid aqueous solution, and then stretching it 4~5 times in one direction.

After stretching, iodine molecules are neatly adsorbed on the film, which has polarization or polarization analysis performance. This kind of polarizer is called H-polarizer. High polarization, up to 99.5%, suitable for the whole visible light range. Its application range is wide; Disadvantages are poor strength, no moisture, easy depolarization and so on.

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