NOTE: Because of its action, the CokinSkylight and UV filters can be left in the Cokinfilter holder most of the time. However, the use of multiple filters must be carefully monitored. Stacking of multiple filters can lead to "vignetting", which is a "clipping" of the four corners of the image and shows up as black corners.
The CokinSkylightfilter stops UV rays eliminating the blue casts and clarifies misty views without any alteration of colours. The Skylightfilter is recommended for landscape photography since it is totally neutral.