Protector Filters page 5

What is a protector filter?

The protector filter is built up from a ring with a plate of sturdy glass attached within. The finish often consists of various coatings, so as well as a protection against knocks and scratches, the filter also keeps water and dirt away from the lens. In addition, the filter is designed in such a way that you will not be bothered by undesirable reflection in your photos. Thanks to the solid construction, a protector filter from Hoya, Sigma or Kenko can last for years.  

Protective function

Protector filters are purely developed for offering protection for your precious lens. It would of course be a pity if it became damaged due to contact with a sharp object. The low purchase costs ensure that in the case of damage to the filter you do not have any expensive repair costs for the lens, but you can replace the filter for a relatively small sum.