Polarizer, also called a polarizer, referred to as PL mirror, a filter. Polarizer outstanding function is selectively to a direction of the vibration of the light to pass through, in color and black and white photography is often used to eliminate or weaken the non metal surface strong reflection, thereby eliminating a reduce spot.

For example, in scenery and landscape photography, commonly used to display the strong reflection of object texture, highlight the glass behind the scenes, pressing dark sky and the blue sky and white clouds. Consists of two pieces of optical glass with a directional role of small polarization properties of crystals (such as mica). There is another kind of manufacturing method, interlayer between two pieces of optical glass coated with polyethylene film or a polyethylene cyanide crystals, the structure of this polymer coating can produce a palisade of very fine, like a miniature fences, allowing only the vibration direction and the same light gap. The two pieces of glass are independently arranged on the ring can rotate by rotating a lens, which can eliminate the polarization of reflected light by perturbation of object surface. This film will gradually aging, and vibration damp and impact, will shorten the service life. In the final analysis, the use of polymer coated PL is consumables, not durable goods. Under normal circumstances, the use of five or six years no problem.

Polarizer is two layers of glass together, between the two layers, made into films through the orientation of crystals, the crystals in order. Polarizer is installed in the rotating frame, the frame of high-speed rotating polarizing axis, there are a few uses in photography:

A: eliminate or weaken the non-metallic reflective surface. Such as glass, window, water surface, a reflecting surface paint and plastic surface.

Two: control the sky brightness, make the sky dark. In the shooting outdoors or scenery photos, sometimes need to screen the sky tone tone control, make the sky dark space, achieve picture sky brightness and ground scenery brightness, adjust the screen tone to. As the sky blue, white clouds pressing tone is more prominent.

Three: as the variable neutral gray color filter. The two polarizing mirror stack, can be used as a variable neutral grey mirror.

Four: to improve the color image color saturation.