In article <59701d$eg2@cnn.Princeton.EDU>, zpzhang@nutmeg.Princeton.EDU says...

>I am a beginner and would like to know your opinion on
>filters in portrait photography (indoor/outdoor, color, non-wedding).
>I have read some books but find first-hand experiences more important.
>Which filters do you use the most or you can not do without?
>If you can only have 5 filters besides UV and (circular polarizers),
>which ones will you pick? Please specify the kind
>of portraiture too.
>BTW, what is your opinion on screw-on vs cokin-like filters?

Hmmm, I think you can do ALL of your photography without filters
(if you think of them as being like condiments, you may see what I
mean). Well-chosen subject matter, placed in good light, and
photographed well is like a gourmet meal, to which one would hesitate
to add salt, pepper, Catchup, relish, mustard, or any other additive
that would change and detract from the experience of something that
is already fine... ;-) Really, though, I think filters ARE overused,
and generally unnecessary (and are best saved for emergencies when
you MUST produce a photo under poor conditions).
Hope This Helps