Beginner

[AgX]

Decades ago there had been long time on offer in Germany special versions of polarizers that in addition got a lateral sealing to keep moisture out of the laminate.

 

[Dismayed]

I use a 1A skylight filter to correct for mixed lighting when shooting color film. Objects in the open are illuminated by direct sun, while those in the shadows are illuminated by the blue sky. A skylight filter blocks the excess blue light emanating from shadows. Yes, it may protect the front element, but the primary purpose is color correction.