Are you really a professional? Do you use a star filter instead of a UV filter? If not, you're probably not a professional.
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At least, according to some guy in China selling filters for US$3.82:
"A Star filter is a must. Period. Most professionals have star filters, not UV filters, permanently mounted on their photo and video equipment."
(http://www.ebay.com.au/itm/350145238507).
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Classic.