Hi Laura, I usually use a polarizing filter, and when out on the water, a UV haze and polarizer (mainly to protect against water splash - I keep a second UV in my bag, after it becomes impossible to clean the first one used).
Lens quality matters, more importantly - getting the exposure right (as close to spot on as possible), keeping a steady arm - and in instances like this - using the fastest shutter speed possible.
I always shoot Canon - either the 300D or ELAN 7E (w/ Fuji slide film).
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{K:5598} 10/26/2006