In article , arifi@war.dmi.stevens-tech.edu says...

>In article <4jm9vg$2nq@newsstand.cit.cornell.edu> d_ruether@hotmail.com (Bob Neuman) writes:
>[...]
>> - Some brands offer, or do not offer, multicoating (which I do not
>> consider important, but you may).

>Could you please elaborate on why multi-coating would not be
>important for filters ?

This may be heretical, but I have never found it to make any
detectable difference, except that the multicoated filters are
MUCH harder to clean thoroughly (probably actually not harder
than non-multicoated, but the minor remains look so much worse
on the multicoated surface). I will go further, and say that I
think it is almost entirely marketing, though POSSIBLY it is a
slight advantage with lenses with an unusually high number of
elements. Having had identical versions of some Nikkors when
multicoating first came out, the only differences I could
detect were in the colors of the (equally prominant)
diaphram reflections when the sun was included
in the image area. Others have worked out
the figures, but as I recall,
transmission and reflection
differences with/without multicoating
are pretty minor, even in multi-element lenses,
until you get up to a fairly high number of elements.
So, adding just one more element to the system is
probably not going to effect the image much,
regardless of the coating type.
Hope This Helps