The classification of optical lenses and the principle of filters

by:Crylight     2021-05-30

What are the advantages of lens coating?

   coated lens can reduce the reflected light on the surface of the lens, see clearly, reduce the reflected light from the mirror surface, increase the light transmittance, and also solve the problem of taking glasses under strong light The problem increases the beauty. Coated glasses can prevent damage to eyesight caused by ultraviolet, infrared, and X-rays. Wearing coated glasses is not easy to fatigue. The eyesight of the staff in front of the fluorescent screen can be protected.

  The coated resin lens should avoid scratching and high temperature, but also avoid acid fume and other erosion. For example, it is best not to wear glasses and cook in daily life, especially for ventilation It is not good when there is a lot of oily smoke; at the same time, you cannot wear (bring) mirrors into (near) hot water showers. Normally, you should put the lens convex side up when you temporarily place it, and put the glasses in the box when you carry it, and don't put it in your pocket casually. Or in a bag, it is very easy to scratch the film.

  Lens material classification:

  Glass lens Optical lens includes optical glass lens and high refractive index lens (commonly called The ultra-thin sheet) has high hardness and good wear resistance. Generally, its quality and various parameters will not change with time, but the impact resistance and weight of glass lenses are slightly inferior to resin lenses.

  Resin lenses are generally much lighter than glass lenses, and their impact resistance is better than glass lenses. They have strong UV resistance, but their surface hardness is low and they are easier to be Bruises. Resin lenses and coated lenses are soft due to their soft characteristics, so you should always be careful not to let the mirror directly touch hard objects. It is best to clean with water (or a small amount of detergent) when scrubbing, and then use a special test cloth or high-quality tissue paper Blot the water droplets on the glasses lens. In addition, the coated lenses should be used with caution in places with poor environmental conditions, so as not to be stained with dirt and difficult to clean.

  Cosmos (PC) lens: high refractive index, strong, but easy to wear. Most of the eyeglasses used in children with small optical lenses, frameless assembly or athlete's eye protection .

  UV lens is also called ultraviolet filter or protective lens, namely UltraViole. It is usually colorless and transparent, but because of the addition of antireflection coating, it will appear purple or purple-red when viewed from certain angles. Many people buy a filter to protect the delicate lens coating, but this is actually just a subsidiary function of it.

The main function of the    filter (protective lens) is to absorb ultraviolet light with a wavelength below 400 nanometers, and has no filtering effect on other visible/invisible light. It can filter ultraviolet rays because the lens contains lead, so the filter is heavier than other lenses of the same size and thickness.

   Filter (protective lens) In photography, the filter (protective lens) is used to protect the lens and filter the light. The lens focus lens in the camera is the most precious. It is necessary to strengthen the protection. The filter lens can be installed to prevent some dust from corroding. Of course, it is very convenient to wipe it. Don't worry about wiping the lens.

   The lens accepts light when shooting, just like people see objects. If you look at things under strong light, you won’t get used to it, and your eyes will be tired, so I put on a filter Glasses, I feel more comfortable for the eyes, because the lenses block a part of the strong ultraviolet rays, allowing the eyes to accept external things in a relieved situation.

   The filter lens on this lens is also the same. It can effectively prevent the intrusion of strong ultraviolet rays to cause the sharpness of the image. Second, it can prevent some air pollution from corroding the lens. When using a traditional camera to shoot with film. Due to the chemical properties of the film, it is particularly sensitive to ultraviolet rays in the sun. In places where the ultraviolet rays are strong, the photos taken with the film are generally bluish and white. The strict aspheric lens greatly affects the photo quality.

   Add a filter (protective lens) in front of the lens, which can effectively filter out ultraviolet rays and improve the clarity of the photo. For high-altitude photography or high-altitude photography, you can make the distant scenery clearer and restore a more realistic and gorgeous picture. So at that time, the filter became a necessary color filter. Because the filter can not only improve the imaging, but also protect the lens from dust, fingerprints and other pollution. and so. The filters are always installed in front of the lens without taking them off, making them the most widely used color filters.

   In the digital age, since the core imaging component CCD of the digital machine is no longer as sensitive to ultraviolet light as the film, the filter (protective lens) has the filtering function of ultraviolet light. It has gradually faded, but the damage to the lens coating still exists due to oil stains, fingerprints, and scratches. The filter at this time plays more of the role of a protective lens.

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