Mk

The Hoya HD nano Mk II UV filter is a no-go area for unwanted ultraviolet light and has other hidden strengths too.

The coatings also repel moisture and grease and make the filter easy to clean. In fact, a UV filter can often actually degrade image quality in some situations. Some photographers might leave a UV filter permanently attached to a lens, for physical protection. Suffice it to say the latter comes through unscathed, while the regular filter is a write-off. Many photographers use UV filters simply to protect the front element of expensive lenses from knocks and scratches. Back in the days of photographic film, a UV filter was often seen as essential for blocking ultraviolet light.