Reviews |Kase K9 Filter Holder Kit

Kase K9 Filter Holder Kit Review

Kase 100 K9 Filter Holder

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Our Verdict

The Kase K9 Filter Holder is well-made and lightweight. Its aluminium construction should mean that it gives years of service, holding filters in place to balance exposure across images, enable long exposures and cut down reflection. Including the polarising filter increases the cost of the kit but it represents good value. Also, the polariser integrates well with the holder so that it’s easy to use with graduated filters.


  • Suitable for a wide range of cameras including full-frame
  • Lightweight but well-made holder
  • Kit includes a magnetic polariser


  • Including the polarising filter increases the cost
  • Limited range of Wolverine 1.1mm filters

What is the K9 Filter Holder Kit?

The Kase K9 Filter Holder is designed to hold 100mm-type square and rectangular filters in its slots, but it also comes with a 90mm slimline magnetic circular polarising filter that snaps into a dedicated holding area right next to the mount on the lens.

What’s a bit different about the K9 filter holder is that, like the smaller Kase K75 Pro 1.1 Holder kit, it has a gear or knurled dial that meshes with the gearing on the edge of the adapter ring filter to enable it to be rotated.

The rectangular filters slip into the slots in front of the polarising filter. By default, these slots are set up to accept the common 2mm-thick filters from the likes of Lee Filters, but they can be changed to accept Kase’s high-quality 1.1mm Wolverine filters.


  • Product type: Filter holder kit
  • Compatible with: Kase Wolverine 1.1mm filters
  • Holder material: Aviation grade aluminium
  • Kit contents: K9 Filter Holder, 90mm Slimline Magnetic circular polarising filter, 77-90mm and 82-90mm Geared adapter rings, 67-82mm and 72-82mm step rings, 2mm and 1.1mm filter slots – 2mm fitted as standard
Kase 100 K9 Filter Holder


Kase makes the K9 filter holder from CNC-milled aviation-grade aluminium, which means it is lightweight but strong. It also has a smart black anodized finished that is designed to reduce reflections.

Once the adapter ring is mounted on the lens, the filter holder clips on easily and can be locked securely. The Polarising filter can then be popped into its position close to the lens front element while the slots are free to accept rectangular filters.

I used the K9 filter holder with Kase’s slim 1.1mm filters, specifically the ND 1000 and Graduated 0.9 ND filters. These slid in smoothly and it’s easy to adjust the position of the graduation. The filters are held tightly enough to stay put without them being awkward to manoeuvre.

Kase K9 Filter Holder Kit review

The red dial seen on the right of the filter holder in the image above enables the 90mm polarising filter to be rotated despite the rectangular filters being in place. You just need to look in the viewfinder or on the camera’s screen to ascertain when you’ve reached the correct orientation for the filter.

Kase opted for a 90mm polarizing filter in the kit because it’s large enough to be used with lenses with focal lengths as short as 16mm. However, when you’re using a very wide lens, it’s important to keep an eye on the distribution of the polarising effect across the image as it can vary depending upon the position of the sun.

Kase Wolverine neutral density filters score on two counts. They are neutral so there’s no colour cast other than might be imparted by your choice of white balance, and they cut out the stated amount of the light.

Kase K9 Filter Holder Kit review

The image above was captured using the Wolverine 100mm medium graduated 0.9 (3 stop) filter to reduce the exposure of the sky to bring out the laden clouds.

I also used the Wolverine ND1000 (10 stop) filter to enable very long exposures to blur movement. A 1/60-second exposure was extended to 15 seconds, for example, to soften a choppy sea while a 1/125-second exposure was extended to 8 seconds to blur the movement of grass in the sand dunes.

Importantly, the detail levels are maintained across the frame when the filter is used.

The Pro HD optical glass that Kase uses for the Wolverine filters is nano-coated to make them easy to clean and is tougher than average so it can survive a drop on to rocks.

Kase 100 K9 Filter Holder

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