I have the complete PolarPro cinematographers collection for the Pocket and love them. The magenetic system for the Action is a good idea for quick swapping of filters but I am concerned about water getting in places it shouldn't.  I would never use an ND filter under water but it's not unreasonable to have a scenario where there is more than just a splash hitting the camera. It would be nice if someone from PolarPro came by to explain the limits.  I don't mind paying the price for high quality filters but it is unclear if these will provide adequate protection for normal action camera use.

I am now leaning toward the Freewell bright day kit but I have never used their filters so not sure how they compare to PolarPro.

Good thoughts. If they don't see your post here, you can ask them directly here:

https://www.polarprofilters.com/pages/support

Hey,

Please be rest assured on the quality of our product it is backed with a lifetime warranty, If you need any help you can directly reach to us on care@freewellgear.com.

All our straight filter such as ND, IR UV, Light pollution filters are waterproof so although you won't use them underwater but you can have a piece of mind if you are going for extreme sports.
All ND/PL filters are splashproof as they have a ring in between.

At the same time, our filter does not have a magnet which means they do not have any magnetic interference even if you want to use them on FPV/Drones.

Thanks
Harry from Freewell  

Hi,

I use PolarPro filters on my Mavic Air and have done for about a year, but went for a Freewell set for my Action.  

The quality of the product (and packaging) is equal to PolarPro: fantastic.  I have the polarized set and really like the feel of them when turning the ring.  Solid and well made.

Thanks for the replies. I think I will go for the Freewell set but I am going to opt for the all day kit.  It's the same price that I was willing to pay for the PP Vivid Cinema series.

col4bin Posted at 5-29 04:46
Thanks for the replies. I think I will go for the Freewell set but I am going to opt for the all day kit.  It's the same price that I was willing to pay for the PP Vivid Cinema series.

I also got PP, yes very handy for switching, I’m not sure how much protection there is in heavy rain, but I have dunked them in water and they are resistant, I didn’t leave them in water for any length of time, I don’t see the practicality of that. Yes it would be nice if PP could say Not waterproof Not water resistant or if they are.
I have a full set of skyreat PL and ND on there way free from skyreat, I have to do a small review on them so it should be done next week if your not in a hurry .

Hello and good day col4bin. Thank you for sharing these information and your insight with regards to this matter. I hope that you will get the best information with regards to this matter. Have a safe and happy filming always.

Jumping in late, but I own a full set of Polar Pro, and Freewell Long exposure kit.  Build of Polarpro maybe a very small amount better than FW, BUT image quality, colour retention and overall use, not a speck of difference between the two. I find myself using the Freewell filters for more than 80% of what I do.

Polarpro has excellent customer service, I broke the first one before I could even use it and they sent a replacement promptly. One also flew off at 55mph despite being supposedly rated to 90mph, received a replacement in 3 days.The 2 piece metal design separated and the glass disappeared into the wind.

That being said, they’re not waterproof and I also lost an Osmo action to water damage, due to not paying attention to their specs.

So I went with a freewell set and it meets or exceeds PPros, is waterproof, and seems to have less lens flare due to the depth of the filter having screw on threads. Whereas the PPro design Is shallower because it’s magnetized and doesn’t use threads - resulting greater lens flare.

I have both Freewell and Polar Pro. I only use the Polar Pro in tamer conditions because of the magnets and because they don't seem to line up with lens gaskets to give a waterproof seal. In conditions where I know I may be exposed to rain or other water sources, Freewell seems to be like the OEM lens cover.