UV filter, also known as ultraviolet filter, refers to a filter used in digital cameras, which plays a role in protecting the lens and improving the picture quality. UV mirrors are usually colorless and transparent. Some will appear purple or purplish red at a specific angle due to the addition of antireflective film. UV lens is usually used to protect the delicate lens coating. In fact, this is only one of its auxiliary functions. UV mirrors can reduce the blue tone caused by ultraviolet light. At the same time, for digital cameras, it can also eliminate the interference of ultraviolet rays on CCD, which helps to improve the clarity and color effect. However, due to the popularity of CMOS, the sensitivity to ultraviolet light is greatly reduced
