Jumping in because I totally agree about the salt. Over the years, I've found B+W 77mm XS-Pro Clear MRC-Nano 010 Filter holds up best against the elements without killing that Art series micro-contrast. Its way cheaper than a front element repair, honestly. Quick tip: bring a fresh microfiber and some Giottos Rocket Air Blaster Large to blow off the dry salt before you even think about wiping the glass.

In my experience shooting coastal events over the years, relying just on a lens hood is a massive gamble. Salt spray is basically liquid sandpaper once it dries on your glass. I have tried many different filters and honestly, the modern ones dont mess with the Sigma Art sharpness like the old cheap stuff used to. You need something that can handle the Maui humidity and salt without making your life difficult or breaking the bank.

• Protect the front element. I usually recommend the Hoya 77mm NXT Plus UV Filter for a solid balance of price and performance. It has great light transmission and the multicoating helps keep your sharpness intact.
• Manage the glare. The Pacific sun is brutal on skin tones and the ocean, so grab a B+W 77mm Master CPL MRC Nano. The nano coating is a lifesaver because it lets you wipe off moisture and sea spray without leaving those annoying greasy streaks that ruin shots. I have found that these two options give you the protection you need without sacrificing the bokeh or color rendition you are used to. It is much better to clean a filter every twenty minutes than to risk scratching that 85mm element during a high-pressure destination shoot. Just keep some fresh wipes on you and you'll be fine.

Coming back to this... I've had some pretty annoying experiences with filters on my Art glass in the past. Took my setup to the coast and unfortunately, the 'pro' filters I bought actually caused some nasty internal reflections when the sun hit 'em. Not as good as expected, honestly. The ghosting was a total vibe killer for those sunset shots. Plus, i found that some coatings are just a nightmare to clean once that salt mist really sets in... it just smears around. Are you mainly looking for something to keep the glass safe from scratches, or are you actually trying to kill some of that harsh Maui glare with a CPL? Also, is your budget pretty open or are you trying to keep it reasonable after dropping the cash on that 85mm? TL;DR: Be careful because even expensive filters can sometimes mess with the Art series micro-contrast and cause flaring in heavy sun.

That 85mm is absolutely amazing! I took mine on a windy coastal shoot last year and the salt mist was everywhere, total nightmare. Quick tip: get a filter with a hardened coating so you can wipe it easily. Are you planning on shooting wide open at f/1.4 in that bright Maui sun? If so, you'll definitely need an ND. Otherwise, I love the Hoya 77mm HD3 UV Filter for keeping that Art sharpness intact without breaking the bank!