Polarizers and polarizers are only different in terms of their names. In fact, they are one type. Polarizers can also be called polarizers. The role of polarizers is more extensive. Polarized sunglasses are useful for polarized light. They are also used in shooting. More, because it can eliminate the reflective stray light and improve the saturation of the color, it is often used when shooting some scenes. Let's take a look at the polarizer and polarizer together. Polarizers are also called polarizers, or PL lenses for short. They are a type of color filter and are often used in photography. The function of the polarizer is mainly to filter out the reflected light and stray light, such as the reflected light of metal, the reflected light of the water surface, the reflected light of the ground, etc., which can block a certain amount of light and improve the clarity and saturation of the picture. It is most widely used when taking landscape photos, especially flowers and blue sky. Generally speaking, it is often used in color and black-and-white photography to eliminate or weaken strong reflections and reduce flare. For example, when shooting scenes, it is often used to express the texture of objects. The polarizer can selectively let light oscillating in a certain direction pass. Generally, the effect of the polarizer is more obvious when the light is on the front side, and the polarized light cannot be eliminated when the light is forward. Because the polarizer filters out a certain amount of light, a certain amount of exposure will be appropriately increased when shooting. Generally need to increase the exposure by 1~2EV. In landscape photos, when you want to show the reflection of the water surface, you cannot use a polarizer because it can filter the light and eliminate the reflection of the water surface together. When shooting in low light, the polarizer will have a certain limit on the combination of aperture and shutter, which is not conducive to controlling hand shake. When photographing people, the use of polarizers should not be abused casually, because it is enough to increase the saturation of the colors, which will cause distortion of the characters to some extent. If the light is too strong, when the side back light enters the lens, the polarizer will cause halos, which will affect the clarity of the picture. Generally, polarizers are commonly used in backlighting and front side light shooting on the water surface, which can effectively eliminate the reflection on the water surface. When shooting the sky, you can eliminate the reflected light and make the clouds stand out. When the shooting light is 90 degrees with the sunlight, it can eliminate the stray light in the air. There are two types of polarizers, one is marked as PL in English, which is a common polarizer, called linear polarizer; the other is called circular polarizer, which is called CPL in English. Both linear polarizers and circular polarizers are not enough to meet the needs of photographers. PL is not suitable for high-automatic digital cameras because it affects metering and auto-focusing. However, CPL works well on this type of camera.