The Formatt 138mm UV2A Haze Schott-Desag B270 Crown Optical Glass Filter is a wise investment. It can help protect your valuable investment from dust, moisture and scratches, which can lead to costly repairs.
It provides virtually 100% UV absorption. The Haze 2A is excellent for conditions where UV is very prevalent such as at high altitude.
If desired it can be left on the lens at all times for protection
Haze filters provide additional benefits of correction for Ultraviolet(UV) light which can register on film and videotape as a bluish cast and can obscure distant details
Ultraviolet filters allow you to correct for the UV effect to varying degrees