In photography, a UV mirror is used to protect the lens and filter light.Camera lens is the most precious, it is necessary to strengthen protection, installed UV lenses, which can not let some dust erosion, of course, in the wipe is also very convenient, do not worry about will rub the lens. Lens in photography to accept light and people to see the object, if it is a strong light to see things will not adapt to, and the eyes will be tired, so wear color filter glasses, feel more comfortable eyes, it is because the lens blocked a part of the strong ultraviolet light, let the eyes in the release of negative circumstances to accept the outside world.The UV lens on this lens is the same, it can effectively prevent the invasion of strong ultraviolet light to create the clarity of the image, two can prevent some air pollution on the corrosion of the lens. When shooting on film with a traditional camera.Due to the chemical characteristics of the film, it is particularly sensitive to the ultraviolet light in the sun, in the strong ultraviolet light, the use of film shot out of the picture is generally blue, white.It seriously affects the quality of the photos.Add a UV mirror in front of the lens, can effectively filter out the ultraviolet light to improve the clarity of the photo.For high mountain photography or high altitude photography, it can make the distant scenery clearer and restore a more real and gorgeous picture.So at that time, UV mirrors became a necessary color filter.Because UV lenses can not only improve the image, but also protect the lens from dust, fingerprints and other contaminants.So.UV mirror is installed in front of the lens all the year round and not removed, become the most widely used color filter. UV mirror lens sunglasses. In the digital era, because the core imaging component CCD of the digital machine is no longer too sensitive to ultraviolet rays like film, the UV filter function of the UV mirror is gradually weakened, but the damage to the lens coating film still exists due to oil stains, fingermarks and scratches.At this time the UV mirror, more play the role of a protective mirror.Some people worry that because of the installation of UV mirror and will affect the quality of imaging.In fact, under normal circumstances, this effect does not open your eyes carefully distinguish can not see, if some specific occasions must need high quality pictures, you can put the UV mirror spin down, shot and then installed.With UV mirror when the need to transfer ring or transfer barrel, here will involve a UV mirror caliber problem.UV lens aperture is usually 46,49,52,55,58,62,67,72,77 (mm), and specifications, such as 82,86,95,105 UV mirror usually professionals to use, also is not very common in the market.When choosing caliber, we need to consider the following two aspects -- the situation of blocking and the situation of dark Angle.Generally speaking, the larger the caliber, the more expensive the lens is (except for 46mm), the easier it is to block the flash, but at the same time it is not easy to have dark corners;The smaller the diameter is just the opposite, not easy to block the flash but easy to have dark corners, but the price of the lens is cheap.