Kase K9 – filter kit (review)


My approach to filters has been changing multiple times over the years. At first, I was their big supporter, using polarisers, NDs (grey filters) and graduated filters. Then, I considered all of them (apart from CPL) to be totally needless – every piece of glass in front of the camera lens decreases a photo quality, right? Not to mention light leaks/lens flares and an inconvenient use of holders which handicaps on location logistics.

Recently, I’ve decided to try going back to the roots, meaning: holder + drop-in filter kit. Why?

I’ve watched a remarkable video by Mark Metternicha, which provided me food for thought. I’m not a big supporter of exposure blending. I don’t bracket every photo and I’m done with collecting several thousand photos during a single trip. A proper selection of the best ones was a bit of a nightmare. Until now – using Nikon D810 or D850 – I haven’t got a problem with exposing frames to the left (side of histogram) and then obtaining the desired details from the shadows. Just one frame and that’s it! Only after watching Mark’s movie have I realised how much I was losing.

Overexposing a photo by 1EV and then lowering exposure by 1EV doubles the amount of useful information in the shadows! That’s the fact.

Now, think how much you lose by extracting 3-4 EV from the dark parts of a photograph. Incredible! The whole “it’s better to underexpose than overexpose” talking I was photographically brought up on can be now considered to be meaningless. Extracting the details from the shadows can be very destructive when it comes to a photo quality!


So, the filters are back in favour. Which ones? I had been using Lee, then I got hold of Breakthrough (I rarely used them, tho). I was faced with a tough choice and my knowledge about the new players on the market was quite limited.

Currently, there are over a dozen leading filter producers. After quick research of the available solutions and reading reviews as well as tests I’ve decided to try out Kase filters. The brand is relatively unknown in Poland, but in many cases lesser-known brands can be better than those considered to be the best (e.g. my FLM beat Gitzo). I seemed to steer in the right direction. How did they performed in practice?


Firstly, I tested K9 Filter Holder Kit which is composed of:

  • K9 holder – attached to the adapter
  • attachment to the 77 and 82mm lens with the adapters to 67 and 72mm
  • additional 1.1mm filter trays (2mm filter trays are pre-assembled)
  • screws and screwdriver
  • 90mm Slimline CPL (polarising filter) –  magnetically attached to the adapter

I also took ND 1000 Kase Wolverine filter for long exposures. These filters can highlight the optical defects (colour cast, lens flares, sharpness reduction), so they are a proper benchmark to check the quality of a given brand.

But first, let’s start with a bit of a theory. When should you use ND and CPL filters?

ND3.0 filter - application

ND3.0 filter, or ND1000, reduces the amount of light reaching an image sensor down to minus 10 EV, so exactly 1024 times. In practice, it means that the exposure time is increased from 1/1000 to 1 sec, from 1/500 to 2 sec, from 1/250 to 4 sec, 1/30 to 30 sec etc.

Why should you expose for that long? In landscape photography, a ND filter is used for capturing a movement. Clouds overflowing the mountain peaks will look completely different while exposing a frame for 1/30 of a second than 30 seconds. Long exposure allows to capture blurred clouds and in this way the viewer has an impression that they’re moving. This procedure increases dynamicity of a scene, often making the frame more interesting for a viewer than a static one. Of course, it is a matter of taste – some like this effect, others don’t. You should be careful not to overuse the ND filter. People usually photograph almost every scene using filter right after they buy it. It’s a specific piece of glass and it should be used wisely. What’s the point of blurring one small cloud and clearing the sky which is not that clear?

Beside clouds blurring, grey filters are often used to capture the water movement. You’ve probably seen the pictures of blurred water in the mountain streams or perfectly flat seas (long exposition flattens the water surface and the waves are no longer visible).

That’s how it actually looks like:

Polarising filter - application

Polarising filter is the most important one for me – I use it most frequently on location. I basically don’t ever remove it from the lens, apart from the situations in which I take wide angle photographs – in this case it’s hard to get rid of uneven polarising effect.

Why should you use a polariser? It:

  • allows to remove reflections (on the water, windows etc.)
  • protects the front lens – I usually use a polariser instead of a UV filter
  • provides better contrast and saturation

Polarising filter also has some disadvantages. The usual problems are:

  • loss of approx. 1.5-2 EV of light
  • price – you shouldn’t buy cheap filters for 20-50 EUR
  • lens flares – connected with a price – the cheaper a filter, the bigger risk of lens flares
  • colour cast – not as significant as in case of ND1000, but often occurring
  • uneven polarisation while using filter on the ultra wide-angle lens

Neutral features

  • dims the sky – it’s the most visible in photos taken at a 90 degrees angle from the direction of incoming light. I know that this effect is not everyone’s favourite, to say the least. I accept it to some degree, but unnaturally black sky is something that makes my eyes sore and also is a very common thing applied by landscape influencers. A cloudless sky? A strong polarisation or graduated filter and problem solved. A photographic nightmare.

Kase K9 - practical experience

Filter holder is made from lightweight material. It also doesn’t require much space – it’s compact which is especially important for me. Usually, the amount of gear and accessories greatly exceeds a permitted hand luggage capacity which was a cause of problems on the airports sometimes :)

Holder can contain up to three 2mm drop-in filters and a CPL filter. For me, it’s even more than a necessity. Typically, I use the combination of polariser and ND filter. Occasionally, when a dynamic range of a scene is too high, graduated filters are the ones to be used.

Design quality is very good and the entirety gives the impression of a very reliable product. All the elements are well-fitted. It works better than the Lee holder which I’ve been using until now.

The system is very intuitive and doesn’t cause difficulties on location. You attach the holder to a special adapter mounted to the lens. Buying the optional magnetic lens cap to every lens allows you to reduce the mounting time  without the need to remove the adapter even when the gear is being transported. In this way, the mounting of holder takes roughly as much time as pulling it out of your bag. CPL filter has a magnetic attachment – it doesn’t need to be screwed. The magnets are strong and there is no possibility that the filter would detach unintentionally.

Demounting is equally effortless. Once the CPL filter is attached, it can be easily manipulated by using a knob which is built in a holder. The filter holder itself is attached by tightening or loosening a single knob. Once the screw is tightened, the holder is stabilised securely on the lens. A slight loosening of the screw allows you to rotate a filter – a feature that can be helpful when using graduated filter. The filters are distinctly tagged on the edges, so there’s no way we mistake various graduated filters.

Kase Wolverine ND 3.0 (ND1000)

The basic criterion in evaluating a filter is a photo quality. In landscape photography, the most important feature is sharpness. Each additional piece of glass in front of the lens causes its decrease in some way or another. You can’t overcome physics. Every filter affects the photo quality, even the UV filters. The question is – is it possible to notice?

I took a few series of photos in which I compared the pictures without filter, with Kase ND3.0 filter and with Breakthrough screw-on filter – to me, this one was the best filter on the market and also was head and shoulders above the products of such companies as Lee or NiSi. How the Kase’s ND compared with the others?

Below you can see a few samples to compare:

My experience of using Breakthrough filters was very positive. It turned out that the sharpness of photos was even better while using Kase. The difference of sharpness when shooting without filter is almost unnoticeable! Incredible!

How did Kase perform in terms of colour scheme and colour cast? Colour scheme is quite a subjective matter, so see for yourself how you like Kase’s colours.

In my opinion, brand new Kase performs slightly better than BT when it comes to reproducing colours. The final effect – colours tend to move towards yellow/green in Kase and orange in Breakthrough. Personally, I prefer the effect obtained by using Kase, but the differences are not that significant and, in both cases, a potential correction only requires the use of ‘eyedropper tool’ in Lightroom and Photoshop.

For the sake of comparison, I found my Lee’s good old resin Big Stopper which I compared to BT and Kase. It turned out that a filter which was the best upon its release on the market now must recognise the superiority of the latest products.

Apart from colour cast, during long exposure times, light leaks and lens flares can be the problems caused by the insufficient tightness of holder. It was quite common when I was using the old Lee holder, but the problem does not occur in Kase. I didn’t have the opportunity to test K9 with an additional graduated filter mounted in the second slot yet. If I decide to buy a ‘ND grad’, this review will be updated.

When it comes to practical aspects, a cleaning of filters is worth mentioning. I still remember rainy days in the mountains as I kept cleaning 150x170mm Lee filters constantly. I was spending more time on cleaning than photographing and it was a traumatising experience. Luckily, Kase filters have nanocoatings on which water/oil runs down easily and they can be cleaned within a split second.

Kase 90mm Slimline CPL

I spent a few weeks on testing CPL Kase filter. I was surprised by the price, or rather lack of it – a filter is a part of K9 kit which costs 169 EUR, so the average price of filters of the same kind. Does it mean that it’s a low-quality filter? Not necessarily. In my opinion, it is an intentional trick. When you buy a holder with filter, you have the opportunity to check the system’s quality and if you’ll be pleased, then the purchase of subsequent filters to complete a kit will be subject to bigger costs. However, the prices wouldn’t be higher than those of the competition, such as Breakthrough or Nisi. The example of ND3.0 shows that the price/quality ratio is very good when it comes to Kase products.

Now, the design quality – there’s nothing to complain about it. Filter looks solid, it rotates with steady resistance. A big advantage is the way of mounting which I mentioned before. CPL filter is magnetic. There is no need of screwing it to the lens. It is easy to mount and demount. The additional advantage is that you can use it without attaching a holder.

The filter worked really well on location. When comparing to the photos without filter, I’ve noticed 1-2 EV light loss. Also, there wasn’t any visible colour cast and the photo quality didn’t decrease. Polarisation is working as it should. When shooting in wide angle – 24mm, vignetting is not visible. The uneven polarisation occurs, just as I thought. But it’s no surprise. Every other polariser works in a similar way. You should keep it in mind, because erasing an uneven polarisation during editing isn’t a pleasant experience. It gets better from 35mm up and the subsequent increase of focal length basically reduces the problem.

Kase @24mm

Kase @35mm

Kase @70mm

Kase @24mm

Breakthrough @24mm

Breakthrough @35mm

Breakthrough @70mm

Breakthrough @24mm


Kase filters do their job. For me, returning to the past, so to the filters which I abandoned a few years ago, was a difficult step. I rather try to limit my gear, but in this case the advantages really surpass the disadvantages. On condition that the filters are used wisely. As for now, I can recommend Kase, but I’ll try to update this test by presenting the samples of competitors’ products (NiSi/Benro) and GND Kase, because I intend to upgrade my collection with another filters.


  • compactness
  • reliable design
  • easy to use
  • minimal / unnoticeable impact on a photo quality
  • very good colour reproduction / unnoticeable color cast
  • low price (adding a CPL filter to a holder kit)
  • possibility of using a CPL filter when a holder isn’t attached
  • magnetic mounting of CPL filter


  • limited availability of filters in Poland (lack of distributor so far)