Skylight filters are Ultra Violet protection plus. Like Ultra Violet (UV) filters, they absorb almost half of UV light, but they also have a very slight pink tint.
When shooting outdoors in open shade or on overcast days, the 'Sky' filter adds warmth and reduces excess blue giving better color rendition.
It is the mildest of warming filters and absorbs only 1/10th of an f-stop of light, therefore requiring no exposure compensation.
Tiffen skylight filters are available in most sizes in standard, mutli-coated for extra flare protection, and thin glass wide angle mount for larger wide angle lenses. vbr>
Note! Tiffen wide-angle filters have low profile rings to prev ent vignetting which can occur when using standard filters on ultra wide angle lenses. They do not have a front thread, and can not accept standard snap on lens caps