The role of uv lens UV filter, UV is not visible, we can not see the naked eye, but a great impact on the image, ultraviolet valley at sunset most, equipped with uv mirror, it can filter more than 95% UV.
Skylight was a touch of magenta appear, it can be used to reduce a small amount of blue and ultraviolet.
Skylight most basic use is to be used to protect the lens amateur. Note that any filter is equal to the film's subject is clear in the light path in the layer of barrier. Therefore, even if only minor impact, but still lower image clarity. In addition, there will also increase the likelihood of glare.