Never wipe sea spray off a lens or filter, sea-spray droplets contain salt ( obviously! ) and as you wipe and dry you will risk wiping dry sea-salt crystals and small sand particles across the filters and resin ones will scratch in about 2 secs flat.
When I'm shooting the coast I always carry one of those little little plastic atomizer spray bottles you can get from any drug store, use clean bottled water. Turn the tripod head away and stand with your back to the spray, spray the filters down as soon as you can with the atomizer to dilute the sea-spray droplets and hopefully wash down any heavy particles, then very gently dab down with lens micro-fibre cloths, anything else will usually leave wet lint trails on the glass and you'll spend more time cleaning smears and crap off the lens than actually taking photos, check for particles and when wipe down with more clean water. Repeat as needed. It's a pain but it's sometimes easier than trying to repair the image in Photoshop. The problem with spray is that all those little droplets will act like little fish-eye lenses on the image and if there's dozens you won't stand a dog's chance of repairing the image so 30-60 seconds prep on site will ensure you go home with some reasonable images.
I once got sea-water into a DSLR body, it didn't blow immediately but the day after the salt water had done it's work and shorted out the power-board and main CPU board and it was £150 insurance claim to have my old 450D body repaired.
Just a crazy idea but you could try getting a couple powerful fans and setting one on each side of the camera face towards the ocean. If they have enough power they probably could keep the mist from hitting your camera. you also would probably need a generator to run them.
photomarkFeatured By OwnerDec 6, 2012Hobbyist Photographer
You have to stop the water from getting to the lens , as Fallis has already said a lens hood is probably your best bet.
If it is spray from the surf then there is very little you can do about it as this spray tend to come it horizontally anyway so a lens hood will not do much.
Salt spray WILL destroy your camera in a very short time so always keep that in mind. I have a number of filters like UV or skylight that I have glued a plastic bag to so no saltwater can ever get to my camera , of course this does not stop the droplet getting on your lens ( or filter )
photomarkFeatured By OwnerDec 7, 2012Hobbyist Photographer
It is a lot harder with square or rectangular filters and a bit of salt water on them generally will not harm them unless they have metal parts but square filters are in most cases just a cut sheet , just always rinse them off after use and avoid wiping them off as this may scratch the surface.
If it is from salt spray, you can go on a less windy day or you can take the lens cap off only just before shooting. Clean your lens frequently. Clean the whole camera before you put it away (salt water is corrosive).
If it is from rain, a lens hood will keep most of the rain off of the lens. Again, only uncover the lens just before you shoot.
If it is from condensation, allow the camera time to reach the same temperature as the environment and keep it in a sealed plastic bag until it does.
One other thing: if salt spray is hitting your camera, then you are probably getting wind-blown sand too. Shooting in these conditions will probably void your warranty and will eventually kill your camera. You need to take steps to prevent damage from sand too. I think what I would do is put the whole camera inside a large clear plastic bag, with just the lens sticking out.