1, the protection of the lens, to avoid direct contact, causing damage;

2, the absorption of the atmosphere of the ultraviolet, to eliminate the fog like, increase the imaging resolution; UV mainly used to prevent the finger touch the lens, dust into the lens. As for the function of the filter to filter out the UV, it is the second.

In addition, before the use of CPL filters and the like, try to remove the UV, can reduce the occurrence of image circle of opportunity, improve the image quality.

When facing the light source, especially at night, please take off the UV. or the lens is not smooth cause the glare will be more powerful. After all, not the integration of the lens, the cuff of error is inevitable.