Freewell K2 Filter System - Magnetic filters changing the game again

The new Freewell K2 compact filter system lets you magnetically attach hard-stop VND filters, like their previous filter system, but k2 also includes a twist, or should I say, an Island. Let's dig into the details of the K2 system, and how it works, and then I’ll tell you my thoughts.

Disclaimer: Freewell did send me the K2 before it went live on their IndieGoGo campaign, but no money was exchanged, they don't get to preview the video before posting and all of these words are my own.

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What comes in the box & Price

Starting off, what comes in the box will change based on which kit you buy, and the k2 is currently on IndieGoGo, so there are several different kits and bonus items. I’ll put all the available filters and kits on screen now. The retail price for these kits starts at $499, but the indiegogo campaign has super early bird and early bird pricing along with bonus filters and cases, so check the link in the description for all the current pricing and bonuses.

I can talk about the kit I have though, which is the VND base kit, along with the blue streak, glow mist 1/8, soft graduated, and case. Let’s put the VND base kit on the camera.

Attaching the Base

To start, we’ll need an adapter. I’ll put the adapter sizes on screen now, but our lens is 77mm, so we’ll go with the 77mm adapter.

Next, we’ll loosen the red thumb screws on the base, press in the red locks, and slide the base to the adapter. Releasing the red locks secures the base system to the camera, but we can still move the base around. This will be more important later, but I always level this based on the built-in level on the back of the base.

Base & Filter Concepts

Onto the fun stuff, adding our filters. Typically if you want to stack filters, you’re either screwing on circular filters or sliding filters into a matte box. K2 has a different take on filter stacking that is much faster than both of those ways.

Attaching the VND Base

Since we’ll be using a VND, we must start with our VND base. This magnetically attaches to the center of our base system. This will allow our VND to change strengths when we adjust it.

If you don’t know how an ND filter works, check out this video I made about no filter vs ND vs ND/PL filters. That will help explain how filters work better than I can get into here.

Attaching the VND

Next, we’ll add our VND, I mostly use the 1-5, and I like a few things about this filter.

First, it magnetically attaches to the front of the camera. This saves time, especially if you’re packing and unpacking or changing filters frequently.

If you want to change to the 6-9 filter, it’s as easy as pulling off the 1-5 and attaching the 6-9. Makes swapping filters a breeze.

The filters also have hard stops on the front to prevent misalignment or cross-polarization. The addition to hard stops on VND’s is such a welcomed addition, as I have other VND filters that do not have hard stops, and when you’re adjusting your exposure with the VND, you’re not looking at the VND markings, you’re looking at your camera’s screen. So it’s very easy to go outside of the polarization range of your filter and have strange vignetting in your images. The hard stops don’t let you go outside of that range.

A unique part of the VNDs is that they can be flipped over and used as different filters. You’ll have to remove the VND base, but by flipping the 1-5 over, you’ll have a CPL filter, and the 6-9 becomes a polarized ND32. These filters do not have hard stops, so you can adjust the CPL any way you need.

My Freewell K2 Color Correction LUTs

The VNDs are also marketed as “True Color” VNDs and are closer in color shift to regular ND filters. Single ND filters have less color shift than variable ND filters, but by putting any filter on your camera, there will be some color shift. The change is subtle, but it’s there. If you’re like me and want to correct any color shifts, I made some LUTs that fix these. You can check those out here.

K2 Island

The next stage, Freewell refers to as the K2 Island and this is one of the bigger changes from their previous magnetic system. This allows you to add specialty filters to the base, like the grad, streak, or glow filters, without moving any magnetic filters on the front. To insert these filters, we’ll open the K2 island on the base and slide in our filters. For the streak and graduated filters, the level on the back of the base allows you to make sure your filters are level while using them.

In my usage, the glow mist 1/8th was the filter that I used the most here. Having the blue streak filter also made of some interesting shots, but I wouldn’t use this filter for every shot as it could get a little overkill after a while.

I’ve only tested the 1/4th glow mist filter and have liked the results. It blooms out the highlights and lifts the shadows, which I’m a very big fan of. They have other more aggressive diffusion filters but the 1/8th isn’t as overpowering and looks more natural, with a hint of mist.

Lens Cap

The magnetic lens cap is the last step in the K2 kit. It’s nice when a filter system includes a lens cap, because if you’re stacking screw on filters, most of the time lens caps arent compatible with the filters. But K2 includes one, and it’s magnetic so you wont scratch your ND filters when you put your camera back in your bag.


The case the comes with the K2 system is very nice for a filter case but it is pretty large. It fits in my bag but is large in the scheme of backpack storage. I’ve had the lowpro 450 AW II for years, and it fits in that bag, but this is a deeper camera bag. If you have a smaller bag, these filters may take up more real estate. The filter case is 3 inches by 5 and a quarter inches high, by 5 and a half inches wide. You can leave the filter system on your camera in your bag with the lens cap attached, but if you want to take the filter case in your bag, make sure it can fit. If it can’t fit in your bag, there is a clip on the back that you could attach it to something else if you want. Freewell does include a carabiner in the box for this.


As great as magnetic filters are, I’m very concerned with how durable the filters are and how well they stick onto the front of the base system. While I’ve been using these filters, they’ve never fallen off or been bumped off accidentally and I’ve put these filters through their paces. My buddy Tyler was doing some fly fishing and said the steel head were jumping up the small waterfall, so I took these filters and spent a few hours filming him fly fishing in a river by my house. I did a filter change, and adjusted the base multiple times and not once was I ever nervous about these filters falling off. I was very happy with how well these filters stayed on my 100-400 when in the river and even walking through the woods with my camera on the tripod and these filters on the end.

My Thoughts & Conclusion

If you shoot photos or videos, filters are one of those things that you know you probably need, but are often the last thing you purchase. Or if you don't know what they are and how they work; again check out my ND filters video to learn more about them.

If you’re looking for an easy-to-use filter system, I’d check out the freewell system and see if these are something that would fit your shooting style. I’ve used them for the past few months and have really enjoyed them. From talking head shoots to the middle of a river, they’ve performed very well.

The expandability and ease of use really sets the Freewell K2 filter system apart from other filters, and I love magnetically swapping filters, especially with the hard stops.

If you want to learn more about ND filters, check out this video here.

About Keith Knittel

I'm a designer from Cleveland, Ohio and love to shoot photos & videos. I made my first website in 2004 to show friends photos & videos (before YouTube/Flickr/Instagram were things) and have been shooting and designing ever since! I have a deep passion for making and helping others create.

View my full About Me

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