Polarized lenses

Polarized lenses are lenses that only allow light in a specific polarization direction from natural light to pass through. Due to its filtering effect, wearing it will make things appear darker. In order to filter out the dazzling rays of the sun shining in equal directions on water, land, or snow, a special coating is added vertically to the lens, which is called a polarizing lens. It is most suitable for outdoor activities such as sea activities, skiing, or fishing.

characteristic:

Although polarizing lenses can filter out many irregular light interferences and avoid dazzling and glaring phenomena, if the curvature of the lens itself cannot conform to the optical standard refractive state, the polarizing effect will be weakened, affecting the authenticity of the image, and the durability will be poor.

After being filtered by polarizing lenses, natural light can only pass in one direction, which can effectively protect the eyes from the interference of cluttered light. The general polarized sunglasses on the market are made by sandwiching polarizing film with fibers. It is different from optical glass polarized sunglasses because of its soft texture, unstable curvature, and difficulty in meeting optical refractive standards after lens assembly, resulting in loose and deformed images. Due to the instability of the curvature, the lens deforms, which directly leads to poor clarity of its transparent structure, image distortion, and inability to achieve normal visual effects. And the surface is prone to scratches, wear, and is not durable.

Polarized lenses are synthesized by pressing multiple thin layers of resin material. Each layer has different functions. The middle layer is a polarizing layer, which works like a louver and can filter out stray reflected light. The second and third layers can filter 99.9% of harmful ultraviolet rays and reduce light intensity, with functions no different from ordinary solar lenses. The fourth and fifth layers of polarizing lenses are impact resistant layers, which make the lenses less prone to breakage; The sixth and seventh layers have been strengthened to make the lenses less prone to wear and tear. Polarizers can filter out harmful light and protect the eyes.

form:

The polarizing mirror consists of two parts: a lens body and a rotatable rear frame connected to it. The lens body is composed of a grating made of extremely fine crystal glass. When rotating, the grating of the polarizer blocks polarized light rays that are not parallel to it. Therefore, a polarizing mirror can control and select the number of reflected light parallel to it (which is polarized light) recorded. This is the reason why polarizing mirrors can eliminate or reduce the reflection of non-metallic surfaces. But most polarizers have a slight blue bias. At the same time, when used for shooting, it will also block non polarized light in the same direction as polarized light vibration. To avoid overly flat colors in the image, it is generally necessary to increase the exposure by one level or more.

effect:

When driving, you will no longer be troubled by the numerous reflections from sunlight and vehicles ahead;

When fishing, the water waves shimmer under the sunshine, but you don't feel uncomfortable at all, instead, you feel comfortable and carefree;

When skiing, you no longer have to worry about reflections and ultraviolet rays, and can glide freely;

4. When it rains, the road traffic signs that flood with rainwater are clearly displayed in front of you;

During vacation, let you fully enjoy the sunshine, beach, and leisure time.

Principle:

The special effect of polarizing lenses is to effectively eliminate and filter out scattered light in the beam. Enable light to enter the visual image of the eyes through the transparent axis on the right track, making the field of view clear and natural. Like the principle of blinds, the light is adjusted to enter the room in the same direction, naturally making the scenery look soft and not dazzling.

The function of PL mirror is to filter reflected light and increase imaging contrast.

PL mirrors can also effectively reduce or eliminate the reflection of non-metallic surfaces, which is a typical polarized light. The reflection of metallic surfaces is more complex and is related to the incident wavelength and surface roughness. The conductivity of metals is not zero, and the reflection coefficient becomes complex, resulting in a change in the phase of the P and S components. At this point, the reflected light becomes elliptically polarized. PL is a line deviation that does not affect the reflection of metal light. By adjusting the polarizer, this part of the reflection can be filtered out, thereby improving the image quality of the subject and enhancing the clarity of the picture. For example, by using a polarizer, the reflection of water can be reduced, allowing for clear capture of fish in the water. When shooting such scenes, the projection angle of the light source should be close to the angle of the camera, and its maximum deflection angle should be between 30-40 degrees. When using it, you can adjust it by slowly rotating the lens in the front group of the filter, striving to minimize the reflection on the surface of the object. In addition, polarizers can effectively improve color saturation and contrast, because polarizers can absorb various directions of stray light reflected by fog or dust in the atmosphere, thereby making the captured image purer. For example, in photography such as still life of flowers, polarizers are often used to take brightly colored photos. It is very useful in landscape photography, floral photography, and capturing certain highly reflective scenery. Polarizers have excellent effects on depicting cloud layers when used for landscape photography. The refractive index of light in blue sky is higher than that of light scattered by white clouds. Polarizers can also be used to make the colors of green leaves more saturated and eliminate fog in low angle urban photography.

Differentiation method:

(1) Find a reflective surface, then hold sunglasses and observe this surface through a lens. Slowly rotate the sunglasses 90 degrees and observe whether the reflected glare decreases or increases. If the sunglasses are polarized sunglasses, you will see a significant reduction in glare.

(2) Place the lens on the computer screen or the LCD screen of a mobile phone, and rotate it around it once. There will be obvious light and shadow, and the font will change from present to absent. These two methods can identify all polarized lenses.

Purchasing tips:

Sunglasses are not only required to be worn in summer, but in fact, they must be used all year round. Wear it on sunny days and even on cloudy days. Don't take it lightly just because the sun is not strong and the weather is not hot on cloudy days, and unknowingly expose yourself to more harmful ultraviolet rays.

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% of ultraviolet rays from penetrating. You can choose polarized sunglasses with the "UV400" best UV blocking label; Poor quality polarized sunglasses, such as dark sunglasses, will enlarge the pupils of the human eye as the light entering the eye becomes darker, increasing the amount of ultraviolet rays entering the eye and causing more damage to the eyes.

Viewing objects as real and natural

The color selection of polarized solar lenses should be based on the principle of not distorting the color of the surrounding environment, having clear edges of objects, and being able to effectively identify different colored signal lights. Especially when driving sunglasses, ensure driving safety. Gray, brown, and green are better colors for lenses because they absorb infrared and ultraviolet rays well, which can improve visual contrast and clarity. They are particularly effective when worn in severe air pollution or foggy conditions.

Will long-term wearing cause discomfort

Authentic polarized sunglasses should be comfortable to wear; Poor quality lenses have no technical or functional capabilities during manufacturing, and the lens materials are also very poor. If you feel uncomfortable, dizzy, headache, dry eyes, stinging, etc. after wearing them, you should stop using them immediately.

Protective function of glasses frame

Most polarized sports sunglasses have a curved frame design that effectively prevents eye irritation from wind and foreign objects during outdoor activities. In addition, the hardness of polarizing lenses and the flexibility of the frame material are both considered to determine whether they will cause harm to the human body.

matters needing attention:

1. There are two types of polarizers: linear polarizer (linear polarizer) and circular polarizer (circular polarizer), and the usage method and effect are the same; But circular deviation can make the light pass through the filter in a circular direction instead of a linear one, which is particularly suitable for cameras with autofocus systems.

When using a single mirror reflex camera, the circular polarizer can ensure the accuracy of focusing due to the use of a reflective lens inside the camera.

Cheaper line polarization may affect the autofocus of some cameras during use, so if using a polarizer on a digital camera, circular polarization is required.

Polarizers are generally thicker and should not be used in conjunction with other filters, as they can easily form black corners in the image.

3. Polarizers themselves absorb about 75% of the light. If used on cloudy days or when using a small aperture fast camera, it is best to stabilize the body with a tripod. Due to the use of TTL metering in digital cameras, there is no need for exposure compensation due to reduced light input.