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Kase K9 Filter Holder

At the end of september, the long-awaited market launch of the Kase K100-K9 filter holder took place in Germany. After photographing with different Kase filter holders for years, I was of course very curious about this release. Although I knew some key data before and had the occasion to make some suggestions for improvement to Kase, in the end it is always different to feel a finished product in one’s hands. Last week I finally got the new holder and put it to the acid test.

The new construction, elegant and light

Left half: K8, right half: K9

After unboxing, I first noticed the filigree and curved construction and its remarkable weight. It had to be much lighter than its predecessor I guessed and the balance confirmed my presumption. The K9 was nearly 20% lighter compared with the K8 model and has 51,5% advantage over the premodel K6 – an impressive reduction! Though the the weight itself is not the key argument for buying it, a more compact holder fits much better into the filter bag and is easier to handle on location. But it should be constructed sturdily enough for its use. And there is no doubt: this CNC-milled, black anodized piece of equipment seems to be built of the highest possible quality. I love it’s balance of weight, sturdiness and usability.

What is new, what has remained the same?

Bottom left to right: K6, K8, above: K9

Compared to the premodels K6 and K8, the engineers have enlarged the inner diameter and mounted smaller filter trays on the K9. This could be a game changer and prevent vignetting on lenses with large diameters or super wide angles (e.G. on a Sony G Master 16-35mm f/2.8 or Nikon Z 14-30mm f/4). With the release of the new filter holder Kase added also a larger magnetic Polarizer of 90mm to the kit. The magnetic feature has been introduced already with the K8 and maintained at the K9.

Beside to the large diameter and the curved shape the two diagonally arranged recesses that make it much easier to remove the polarizing filter from the holder.

Two diagonally arranged recesses

But the Kase developers did not only pay attention to the polarizer’s accessibility. Grace to its slim corners it has become dead easy to pull in or out a square ND when the graduated ND is inserted in the second slot. For all square filter users (there are also 100 x 150mm ND versions available from Kase) it is important to accurately set the filter’s position in order to avoid light leaking either at the holder’s top or bottom. Just have an eye on that.

The successful concept of one-handed handling (rotation and fixation of the holder by a single set screw) has been continued successfully, the red aluminium locking screw is still working clean and accurate, same as on its predecessors. Only the tread lead has changed. The K9 now requires less than three full rotations while the K6 and K8 needed 4.5 turns until the holder was firmly seated. In addition to this subtle innovation Kase has also placed a socket between the holder and the screw head, which improves the accessibility by far when wearing winter gloves. And there is another improvement on the opposite side: A bigger gear wheel helps turning the polarizer. Who is traveling in the cold, will appreciate that.

The set screw mounted on a socket
Revised bigger gear wheel (right)

As far as I can assess, Kase has optimized the friction of its filter trays to the best. The filters now slide in and out very smooth can be done without significant effort with just one hand. I had filter holders in use once, where it was always needed to hold the lens with the second hand. I think Kase has done a very good job with the new trays. For those who want to adapt the friction to their own specific needs, can tighten or loosen the fixing screws within certain limits. A small allen wrench is included in the box, but you should handle it carefully, otherwise it will bend.

What’s in the box?

The K100-K9 filter holder-kit comes with all you need for adapting rectangular filters on lenses between 67mm and 82mm diameter. In addition you get different filter trays. You can mount regular 2mm filters (pre-installed) or slim filters 1.1mm. As mentioned, an allen wrench for the replacement work is also included. At the beginning of 2020 a 86mm adapter ring should complete the range of adaptable lenses and makes it possible to use the K9 to lenses with 86mm filter thread. For me an important feature because I will be able to mount my ND and GND filters together with a polarizer on the Laowa 17mm f4. Although I can do so already today (but without polarizer) but I had to have a special adapter ring turned off by the metal processor out of a 86-105mm step-up ring.

Kase K100-K9 Holder Kit
  • K100-K9 filter holder made of aluminium
  • 90mm magnetic circ. polarizer, Schott glass B270, multi-coated
  • Adapter rings 1x 77mm, 1x 82mm made of steel
  • Step-Up Rings 1x 67-82mm, 1x 72-82mm
  • 3 filter trays for 2mm filters + screws
  • 3 filter trays for 1.1mm slim filter + screws
  • Allen wrench
  • Replacement gaskets

My Conclusion

A filter holder takes a key position in my equipment as the linking part between camera and filters. A filter holder takes a key position in my equipment as the linking part between camera and filters. Therefore my expectations were high. With the K9 all my wishes were not just only fulfilled, but exceeded by far and I really love working with it. With all the small useful features, the Kase K9 is one of the best 100mm filter holders on the market.

If you like to purchase a K9 Holder Kit, you can do so on the website of Kase Filters Germany.

Disclaimer: Although I am a brand ambassador, I ordered the K9 Holder Kit on the same conditions as the customers (with a small discount). So this is not only a product presentation but rather a personal and independent report of experience including both, positive and negative aspects of the filter holder. I wish you all the best and good light!