Hoya UV(N) HMC Filter - What does the N mean

[overclockp]

I see cheap filters with UV(N) but never a description of what the N means. I also see UV(0). Is there a difference?

 

[overclockp]

anyone, anyone?

 

[Gautam Majumdar]

Hoya's current filter line does not have UV(N) or UV(O) - only Haze UV. So I have to enter the guessing game. N could stand for neutral - to differentiate it from slightly pink Skylight-UV filters. Or N could stand for Near - that it protects against Near-UV, i.e, close to the violet & not more energetic Far-UV. Can't even guess what could be "O".
--
Gautam

 

[overclockp]

After some very extensive research I found two differing explanations:

1. UV(N) is the Japanese market equivalent of the UV(0).
2. UV(N) filters are made from cheaper glass than the UV(0) filters.

These filters are found on ebay being shipped from Taiwan. They are nowhere else at all. Even the auctions do not tell what the "N" stands for.