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  • Writer's picturePaulo Pereira

Kase K9 System Wolverine filters

Updated: Dec 6, 2020


Since I moved to digital, filters are part of my process as a landscape photographer.

Providing the best hours of the day for photography, typically sunrise and sunset, filters became a fundamental part of obtaining better images.

During the first years, like the most photographers, I started by using circular filters and, quickly as I added lenses to my kit, I realized that circular screwing filters were a waste of money and space, with serious technical issues regarding quality and versatibility.

It was in 2014 that I've decided to purchase a square filter system. At the time, LEE systems were offering the best quality and reputation, so I've purchased a set for my needs. For years I've used LEE and I was fully satisfied with the results. In recent years, other brands have emerged on the market with better evolutionary systems and with glass filters that claimed better quality than the LEE resine filters. For some time, accustomed to LEE, I resisted changing brands and waited for LEE to launch new filters.

In 2019, in a trip to Lofoten I had the opportunity to try the new Haida system and I liked what I saw. I liked the system and the quality of the filters. Right after returning home, I sold my LEE kit and bought a new set from Haida, which I keep at the time of this review.

I have heard of Kase a few years ago, but never really had tried the filters before.

Recently, Kase asked me to trial its filter system, which I agreed to do, so this review represents my own honest and independent thoughts on these filters, after using them out on location over the past 2 months. It should be noted that, at the date of this review, I have no agreement or contract with Kase or another brand of filters, and that the Master Kit they sent me for testing will be returned after this article is completed.

#1 Wolverine Master Kit, what's included in the pack ?

K9 filter holder

Magnetic Circular Polariser

1x adapter ring 67mm with thread for 77mm Kase round filters

1x adapter ring 72mm with thread for 77mm Kase round filters

1x adapter ring 77mm with thread for 77mm Kase round filters

1x adapter ring 82mm with thread for 82mm Kase round filters

Wolverine 100x150mm S-GND filter 0.9 (3 stop Soft Grad)

Wolverine 100x150mm S-GND filter 1.2 (4 stop Soft Grad)

Wolverine 100x150mm R-GND filter 0.9 (3 Stop Reverse Grad)

Wolverine 100x100mm 1.8 ( 6 stop ) ND filter

Wolverine 100x100mm 3 ( 10 stop ) ND filter

Filter bag that holds up to 10 filters and holder

Extra filter added to the kit:

Wolverine 100x100mm 0.9 ( 3 stop ) ND filter

#2 K9 100mm Filter Holder

The most recent K9 holder it's an update of the K8 version.

Despite not having tried the K8, from what I was told, it had some problems with vignetting while using ultra wide angle lenses. As I tested the K9 with my Sony FE 16-35 f2.8 lens, and didn't notice any vignetting, I can say that Kase did a great job with the K9 version, figuring out a solution for this issue.

At first glance, the holder seems pretty fragile, but believe me that after you hold it and use it, you'll realize that it's very light but sturdy enough for the job.

This aluminun CNC-milled black anodized piece of equipment seems to have been built with the highest quality possible.

There’s a small wheel on the holder that enables you to turn the polariser to the required position.

It is fitted standard with two slots for 2mm thick filters and it's possible to change it for three filter slots. Because Kase also has filters with 1.1 mm thickness, a set of 1.1 mm slots are included. However, it is not possible to combine the 2mm and 1.1 mm thick filters.

Unlike some other brands, Kase placed the gasket in the holder slots and not in the filters. This seems to me to be a good solution, because, in other systems I have used with the gasket placed on the filters, depending on the time of use, the storage mode and the environment where are used, tend to peel off the filter.

The holder mounts very easily to the adapter ring. It attaches to the adapter ring using a screw type knob to ensure there is no accidental removal. In most other brands with similar systems, the support is loose on the ring, allowing it to rotate freely when required. This may seem like a disadvantage of the Kase system, but to rotate the holder, just loose the knob slightly and it will rotate still firmly attached to ring adaptor.

However, the fact that it is possible to tighten the holder, has the advantage of giving us the confidence that is very secure and the filters will not fall. As a travel photography leader and educator, I always tell my participants that they must remove and pack the filters before changing locations, even if it is only a few tens of meters. With the Kase system, I felt perfectly comfortable walking with the tripod over my shoulder, holding the camera with the filters mounted, while changing locations. It may not seem like a big deal, but this simple fact is extremely important in a holder when we are outdoors shooting. Sometimes, we have situations where the camera is standing vertically on a cliff or over a bridge, where the fall of the holder implies the total loss of the filters. Believe me, I've seen it more times than I wished to...

So, my advice goes in the way that the K9 Kase holder is a great choice for all those who have a tendency to drop the filter holder, or who usually use it in places where a fall does not allow their recovery.

#3 K9 100mm magnet adaptor ring

It comes in several diameters sizes, according to the size of each lenses.

What sets Kase's adapter rings apart from other systems is that they are magnetic. In addition to being the base of the holder, it also allows you to use Kase's magnetic circular filters directly on the ring without screwing or using the holder. This is a great advantage when you only want to use the polarizing filter.

#4 Wolverine 100mm Neutral Density filters

All 3 ND Filters tested are made of 2mm thick shockproof optical glass, nearly unbreakable.

IR-CUT Infrared cut-off coating scratch resistant and waterproof mould resistant.

Neutral density filters serve to increase the exposure time and thus allow a series of possibilities for the photographer. The increase in the exposure time allows, for example, eliminating objects or people in motion in a static setting; smoothing water movement or dragging clouds.

However, it is expected that the use of this type of filters would also translate into a quality image, without loss of sharpness or a large color cast.

In the past, almost all options in the market, namely in the 10-stop filters produced an extreme color cast that was almost impossible to deal with, which is why I stopped using this filter and it is not even part of my usual kit. As I usually shoot in low light hours, the 6-stop filter is enough to increase the exposure I normally aim for.

Today's reality has changed and it is now possible to produce a piece of dark glass with quality to be used in photography.

The tests carried out on Kase Wolverine filters were carried out in order to verify their density, sharpness, vignetting and color cast.

For this, they were used in a situation of low light and against the sun, a situation that is often the preferred scenario of a photographer.

In order to test the filters it is necessary that the comparison tests are carried out in a very short time for the light to be comparable.

It is also important that all camera settings are manual, including the white balance which is essential for checking the color cast.

Leaving the machine in fully automatic mode, makes it seek to compensate for both the exposure time and the white balance when you have a glass in front of it. And it should be noted that not all cameras are capable of performing an exposure measurement with a 10stops filter in front of the lens.

The images below are the raw exported from Lightroom without any adjustments made.

Wolverine 100x100mm ND0.9 ( 3 stop ) filter

Camera Settings:

- Manual mode

- White Balance set to shades.


The ND 0.9 filter has a very slight underexposure, as we can see in the histogram.

An exposure correction of +0.3 in Lightroom matches both histograms.


No vignetting.


No visible loss of sharpness.


The Kase ND 0.9 filter has no color cast or color saturation.

Wolverine 100x100mm ND1.8 ( 6 stop ) filter

Camera Settings:

- Manual mode

- White Balance set to shades.


The ND 1.8 filter also has a very slight underexposure, as we can see in the histogram.

An exposure correction of +0.5 in Lightroom matches both histograms.


No vignetting.


No visible loss of sharpness.


The Kase ND 1.8 filter has no color cast and a very slight color saturation.

Wolverine 100x100mm ND3 ( 10 stop ) filter

Camera Settings:

- Manual mode

- White Balance set to shades.


The ND 3 filter also has some underexposure, as we can see in the histogram.

An exposure correction of +0.8 in Lightroom matches both histograms.


No vignetting.


No visible loss of sharpness.


The Kase ND3 filter has some color cast and a very slight color saturation.

The slight color cast can be corrected in Lightroom with the following settings corrections:

- white balance: - 400kelvins

- tint: -14 value

After correction in lightroom:

In summary, the Kase ND filters have a good glass quality, maintaining sharpness and without abusive color cast. The color cast is only visible in the ND3 filter, what is normal in this type of filters and easily corrected in post production. The test was done with custom WB, but in case the photographer chooses to use the AWB mode, the camera automatically makes adjustments that corrects a large part of this color cast in the ND3 filter. In any case, it is normal for ND3 filters to have some color cast and this one from Kase is one of the best I have ever seen and is easily corrected.

I also tested the issue of water accumulation on the filter and I can say that after wetting the filter it does not accumulate water or drops and it can be cleaned very easily without spreading.

#5 Wolverine 150x100mm Grad Neutral Density filters

A graduated neutral-density filter, also known as a GND filter, split neutral-density filter.

It is an optical filter that has a variable light transmission. Typically half of the filter has neutral density which fades, either abruptly, gradually or very smoothly, into the other half which is clear. It is used to bring an overly-bright part of a scene into the dynamic range of the sensor.

It is typically very useful when photographing sunrise or sunset, where the light in the sky is much brighter than the one in the ground.

Testing the Grad Filter on a Sony A7RIV with a 16-35 f2.8 lense
Wolverine 100x100mm GNDS0.9 ( 3 stop ) soft filter

Camera Settings:

- Aperture mode

- White Balance set to shades.

Wolverine 100x100mm GNDS1.2 ( 4 stop ) soft filter

Camera Settings:

- Manual mode

- White Balance set to shades.


No vignetting.


No visible loss of sharpness.


The Kase GND filters has no color cast or color saturation.

There is no right filter for every situation. Each case is different, so, Kase offers graduated filters with different densities and different types of transition.

These 2 filters both manage to solve the dynamic range of the scene. The fact that they have a soft transition, makes it hard to understand the correct transition point, when placing the filter, but, because of that, it is also not essential that the filter is placed in the exact right place, because, in the final image, it is not noticeable the transition point of the filter as opposed to the hard transition type, which need to be very well placed so the transition marks in the final photo are unnoticeable.

#6 Wolverine 150x100mm Grad Neutral Density Reverse filter

The GND Reverse filter is similar to the GND, except that instead of having a dark part at the top that gradually fades to neutral, it has a darker central part in the filter that fades smoothly to the less darker upper part and to the lower neutral part.

This filter has been specially designed for bright light situations in the horizon, typically useful for photographing sunrise and sunset, directly in the frame.

Sometimes, it is convenient to use it simultaneously with a GND filter to help balance the light.

Like any other type of filter, it should not be used just because we have it. If there is anything at the first plan that goes from the neutral part of the filter throught the dark zone, it’s going to mess it up. Plain and simple, just don’t do it. When used wisely, it can achieve great results.


No vignetting.


No visible loss of sharpness.


The Kase GND reverse 0.9 filter has no evident color cast, but shows some color saturation mainly on the dark zone.

As you can see in the image above, the use of the filter in this type of situation balances the tones of the photo. In the histogram you can easily see a much higher concentration of midtones, with less highlights and less shadows being really evident.

#7 Magnetic Circular Polarizer Filter

They’re especially well suited to outdoor photography because of the way they can counteract the natural glare of sunlight.

They can be usefull in cases where cutting through glare will improve contrast and make colors pop. By reducing the glare of reflections, they can help peer through transparent reflective surfaces.

The problem of using CPL with ultra wide lenses is well known. As the polarization reaches its best at 90º from the light source and, due to the wide angle lenses having fields of vision greater than 90º, creates dark areas in the image that are hard to deal with it in post-production.

This problem starts to be less visible in lenses after 50mm. Being the 16-35mm, the lens of excellence for landscape photography, and as I try to privilege the so-called noble hours to photograph, often with the sun falling directly, I end up not using this type of filter as much, as the correction of these dark zones in post production is complicated to achieve.

However, the filter is very useful when we close the frame and when we have brightness on the surfaces. Other optimal uses for this type of filter are in forest areas, to enhance some shades, such as greens, and remove glare from any light entering. The use of it in street photography is also something to consider, namely after recent rain that leaves the surfaces wet and shiny, in addition to the city, where we have many glazed surfaces that can cause, sometimes, unwanted reflections.

The polarizing filter from Kase despite not being the best of the best product in this range line, it is still identical to many others that I have used. In terms of quality and use, I find some similarity between Kase and Haida's polarizers, both designed to work close to the lens.

This is a big question that has plagued the photographers'' community for a long time and without a definitive answer.

When stacking the CPL with the ND or GND, should the CPL be placed next to the lens or at the end of the stack?

I've seen and I've used both solutions. There are colleagues who defend a method, there are others who argue that the opposite is correct.

Perhaps the response is not uniform and will depend on the brand and the constructive characteristics of the filters.

I used the LEE system for 5 years with the polarizing filter furthest from the lens and never noticed any problems in the images because of that. Then, I started using Haida's system with the CPL drop-in, which is placed just in front of the lens and I also did not notice any issues.

Bearing this in mind, when testing Kase's CPL, I tested a CPL with an ND0.9 stacked and also tested with the position of the filters inverted.

CPL + ND0.9 ( CPL in front of the lens ) Kase filters

In this model, the CPL works well, almost, the same way as when alone. Obviously, there is a loss of brightness due to having a neutral density filter to obscure the lens.

CPL + ND1.8 ( CPL in front of the lens ) Kase filters

It is practically unnecessary and not functional to use the CPL, since the light reduction given by the ND1.8 is too much for an effective use of the CPL.

ND0.9 + CPL ( ND in front of the lens ) Kase filters

In this mode, with the order of the filters inverted according to Kase's concept, a brownish tone is very noticeable.

So, regarding Kase's filters the answer is that the polarizer should be in front of the lens.

It can be seen in the photos above and in the crop images, the effect of polarization removing the brightness in the window and in the metal tube.

Kase, like other brands, has a dilemma in the design of these filters systems. A filter with a higher density, and as such, more visible polarization strenght will make the holder thicker and probably cause vignetting with wide angle lenses.

So many brands have idealized their systems so that the polarizing filter is placed close to the lens and have it done ultra slim in order to allow the use of more filters without causing vignetting.

Kase's filter, like others, have a low density, and when polarized, it produces a loss of 1.2 EV while my older LEE 105mm polarizer looses about 2 EV.

During the tests of Kase's polarizer, I had, in some moments of low light, dificulties to perceive if it was fully polarized or not, even with the help of the histogram on the camera LCD, the change in the histogram was minimal. During normal hours of the day it was relatively easy to notice the polarization of surfaces with glare and reflections. I must also mention that, perhaps, due to the low density of the filter, the saturation of the blue sky is not very accentuated when polarized.

As I mentioned, I have and had several polarizing filters, either circular to screw, or circular for so-called square systems.

From Hoya, Thiffen, B&W to LEE105, Haida Drop-in, the one that has satisfied me the most to this date was the polarized LEE105mm. In addition to having a good visible polarization, it also had a slight warm bias that, in addition to increasing contrast in skies, also helps to enhance green, brown, and gold tones.

Regarding Kase's filter, although functional, it would be great if it had some more polarization strenght, and, why not, also done a slight heating of the warm tones that photographers always appreciate.

Did I mention that Kase's polarizer is magnetic? No ?

This is where the filter stands out. The ease and speed with which you remove and insert the filter is very useful. Of course, when we have the holder with more filters in it, we have to remove it to remove the filter, but as the filter magnetizes with the ring, we just momentarily have to remove the holder, remove the filter and remount the holder.

For those who enjoy street photography, it is very easy to use, as they do not need the holder to place the filter. Just use the adapter ring and place the filter directly on the magnet ring without having to screw it in. Thus making the set easier to use and more discreet in street photography and even in other handheld situations that require the use of the polarizer.

#8 Lens caps

The lens caps are available in 2 options. Plug-in plastics or magnetic metal alloy.

Whichever option is chosen, the caps are a fundamental part to have in a photographer's kit.

In these square filter systems, where it is necessary to use an adapter ring on the lens, it is not practical to always be removing the ring to attach the original lens cap. Therefore, these Kase caps are essential to protect the lens when it is placed in the backpack, avoiding possible scratches and, even when we walk with the camera in hand, protecting the lens from possible shock.

Kase caps can be used directly on the magnetic ring adaptor or even with the holder mounted.

Likewise, even with the CPL in place, they can still be used, thus also protecting the polarizing filter.

#9 Conclusions

Would I advise photographers to buy Kase's K9 100mm filter system? Yes, I would without doubt. Although it is not perfect and subject for improvement, there is no such thing as a perfect filter system. Each system have it's own pros and cons, but Kase's K9 it is a very user friendly filter system. It works very well and it is very flexible when used outdoors. I really like the magnet concept for the polarizer and also the fact that the holder is really rock solid when proper tightened to the magnet ring. A full system is expensive so it's far better to trust a holder tight system that holds our expensive filters.

What I like:

- The filter holder is very well constructed

- The filter holder is very light

- locking mechanism to prevent holder from rotating and/or dropping

- Filters have a very good quality feel

- Unbreakable Filters ( did not test it )

- No vignetting

- Polarizer magnetic concept, what allows the use of CPL with or without placing the holder

- Rotation dial for the polarization filter is large enough to use it with winter gloves

- High quality glass

- Large filters range options

What I dislike:

- Polarizer strenght

- Slight color cast in ND3 filter

- The need to remove holder or filters to place or remove the CPL

#10 My "must have" selection of a filter kit for landscape photography

K9 filter holder

Magnetic Circular Polariser

1x adapter ring XXmm for each lenses owned

1x Tap cover for each ring

Wolverine 100x150mm SGND filter 0.9 (3 stop Soft Grad)

Wolverine 100x150mm MGND filter 0.9 (3 stop Medium Grad)

Wolverine 100x150mm R-GND filter 0.9 (3 Stop Reverse Grad)

Wolverine 100x100mm 0.9 ( 3 stop ) ND filter

Wolverine 100x100mm 1.8 ( 6 stop ) ND filter

#11 Equipment used

Sony A7RIV

Sony FE 16-35 f2.8 G Master

Leofoto LN364C tripod

Really Right Stuff BH-55 Ball Head

#12 Some images shooted with Kase Filters

"Sr.da Pedra" Chapel | Miramar | Portugal: Kase ND 3 stops & 3 stop Soft Grad ND
"Sr.da Pedra" Chapel | Miramar | Portugal: Kase ND 6 stops
Corvo crater | Azores | Portugal: Kase 4 stop Soft Grad ND

#13 KASE Portugal

You can purchase Kase's filters at a special price through this link or via email.


* Discount code: PPEREIRA5%

* 5% discount on the first buy for 75, 100, 150mm square filter systems, applied before shipping and Taxes.

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