What is the principle of polarizer?

Abstract: Polarizer is a special kind of lens. Its working principle is to selectively filter the light from a certain direction by using the polarization principle of light, thus weakening the light. Polarizer can reduce the reflection of scrap metal surface and water surface, so it is used in the field of sunglasses and camera lens. The outdoor sun is poisonous in summer, so it is a good choice to wear a pair of polarized sunglasses to go out. When buying polarized sunglasses, we should pay attention to the quality, see if things are natural, whether they will be uncomfortable after watching them for a long time and so on. Let's take a look at the principle of polarizer! 1. What is a polarizer?

Polarizer is a lens made according to the polarization principle of light, which is used to exclude and filter the scattered light in the light beam, so that the light enters the eye visual image on the right transmission axis, and the visual field is clear and natural. Mostly used in sunglasses and camera lenses.

Second, the principle of polarizer

The function of polarizer is to filter the reflected light and increase the imaging contrast. Its working principle is to selectively filter light from a certain direction. By filtering out a lot of polarized light in diffuse reflection, the light intensity in the sky is weakened, the sky is darkened and the contrast between the blue sky and white clouds is increased. Look at the viewfinder and rotate the front mirror when shooting. In the viewfinder, the effect is most obvious when the sky is darkest, and the difference between the darkest and the most appearance is 90 degrees. You can turn to any angle between the darkest and brightest as needed.

The polarizer can also effectively weaken or eliminate the reflection from the nonmetal surface, which is a typical polarized light (the light reflected from the metal surface is not polarized light, and the polarizer has no effect on it). By adjusting the polarizer, this part of the reflection can be filtered out, thus improving the quality of the subject and the clarity of the picture.

For example, using a polarizer can reduce the reflection of the water surface, so that you can clearly photograph the fish in the water. When shooting such a scene, the projection angle of the light source should be close to the projection angle of the camera, and the maximum deflection angle should be between 30 and 40 degrees. When in use, it can be adjusted by slowly rotating the lens in front of the filter to minimize the reflection on the scene surface. In addition, the polarizer can effectively improve the color saturation and contrast, because it can absorb the stray light reflected by fog or dust in all directions in the atmosphere, thus making the photographed image more pure.

For example, in the still life photography of flowers, a polarizer is often used to take color photos. It is very useful in landscape photography, flower photography and shooting some specific scenes with strong reflection. When the polarizer is used to take landscape photos, it has an excellent effect on depicting clouds. The refractive index of light in the blue sky is greater than that of light scattered by white clouds. Using polarizer can also make the color of green leaves more saturated and eliminate the fog of shooting urban scenery at low angles.

Third, the purchase skills of polarized sunglasses

Sunglasses are not only needed in summer, but also all year round. Wear it on sunny and cloudy days. Don't think that if the sun is not strong and the weather is not hot on cloudy days, you will take it lightly and unconsciously expose more harmful ultraviolet rays.

1, the primary consideration is quality.

The primary function of polarized sunglasses is to prevent ultraviolet rays and filter polarized light. Good polarized sunglasses lenses can block more than 90% ultraviolet rays. You can choose polarized sunglasses with "UV400" logo, and it is best to block ultraviolet rays; Inferior polarized sunglasses, such as dark sunglasses, with the light entering the human eye darkening, the pupil of the human eye will become larger, and the ultraviolet rays entering the eye will increase, which will increase the damage to the eyes.

2. See things as they are.

The color selection of polarized sunglasses should be based on the principles of undistorted surrounding color, clear object edge and effective identification of different color signal lights. Especially when driving with sunglasses, ensure driving safety. The colors of lenses are gray, brown and green, because these colors of lenses can better absorb infrared rays and ultraviolet rays, and can improve visual contrast and clarity, especially when the air pollution is serious or foggy.

3. Will it be uncomfortable to wear it for a long time?

Authentic polarized sunglasses are comfortable to wear; Inferior lenses have no technology and functionality when they are manufactured, and the lens materials are also very poor. If you feel uncomfortable, dizzy, headache, dry eyes and tingling after wearing it, you should stop using it immediately.

4. Look at the protective role of the picture frame

Most polarized sports sunglasses frames are designed with curved surfaces, which can effectively prevent the wind and foreign objects from irritating the eyes during outdoor sports. In addition, the hardness of polarizing lens and the elasticity of frame material take into account whether it will cause harm to human body.