70-200 F4L and Tamron 17-50 - both use 67mm filter...question about that

Hey,

I've got a $100 gift certificate at a local camera shop and I was thinking of getting a filter for both of my main lenses that I use the most. I'm noticing that they both accept a 67mm filter.

Is it normal to just buy one filter and 'share' between the two? Also, without ever having purchased filters before, what are good high quality brands, and what is more useful - a UV filter or a CPL filter?

What are the main purposes of either type? Is there something better to look at?

Thanks in advance.

Paul

I'd say go for the circular polarizer, try to get a hoya or a b+w if you can, UV filters are used to cut down on the haze or fogginess you get when shooting on a really bright day, plus they protect your lens, think about it, would you rather scratch a $100 filter or a $500 lens? the cpl will do that plus enhance colors when shooting outdoors, here is a nice writeup on CPL, hope it helped.
http://www.the-digital-picture.com …arizer-Filter-Review.aspx