Digital Camera World Verdict

Kase’s aviation-grade aluminum filter holder has a high-quality feel yet is lightweight and fairly low-profile. Once the holder is in place, it’s easy to attach the magnetic polariser and it can be rotated into the desired position without touching the filter or moving the whole holder.

Pros

+
Lightweight metal construction
+
Kit includes a magnetic polariser
+
Accepts a wide range of 100mm filters

Cons

-
Including the polariser increases the cost
-
Lee Filters filters don’t thread as smoothly as Kase’s
-
The holder clip isn’t sprung

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Kase offers an extensive range of filters with everything from 150 x 170mm filters to rear-mounted filters that slot into the back of some lenses. There’s also a choice of circular magnetic filters and square or rectangular filters that slot into one of the company’s holders.

There are two different-sized filter holders in Kase’s range, a small one for 75mm-type filters that are suited to small mirrorless cameras and two holders that are designed for 100mm-type filters. These are the Kase Wolverine Armour 100mm Filter Holder system that has magnetic frames to surround 100mm rectangular filters and the more widely known Kase Wolverine K9 100mm Filter holder reviewed here.

Specifications

Kase Wolverine Series K9 Filter Holder review — (Image credit: Angela Nicholson / Digital Camera World)

Filter size: 100mm type filters

Mount: Screw-fit via adapter rings

Construction: Aviation-grade aluminum and plastic filter guides

Key features

Although Kase sells the Wolverine Series K9 Filter Holder by itself, it primarily sells it as a kit with the 90mm magnetic circular polarizing filter as the two are designed to work together. The polariser frame has a magnetic rim that holds it onto the magnetic geared adapter ring which has a knurled edge that knits with the cog in the side of the holder. This allows the polariser to be rotated without touching the filter directly.

The holder is designed to take 100mm type square or rectangular filters, and in the USA, it comes with two different sizes of slot, 2mm and 1.1mm. The 2mm slots are fitted as standard as that’s suitable for most 100mm-type filters. In the UK, only the 2mm slots are provided, but 1.1mm slots can be supplied by special order.

Kase used to offer a small collection of 1.1mm-thick 100mm-type filters, but production has now ceased as 2mm filters are much more widely used.

Kase supplies the holder with two geared adapter rings to mount it on a lens. These are 77-90mm and 82-90mm. This means they can be mounted on the lens with a 77mm or an 82mm filter thread. However, there are also two step-rings in the box which enable the holder to be mounted on lenses with a 67mm or 72mm thread.

Build and handling

The Kase Wolverine Series K9 filter holder is made from aviation-grade aluminum which is CNC-machined, and it has a nice matte-black anodized finish. The filter slots, two on each side of the holder, are made from plastic and there are graduation marks on the front to help guide the positioning of a graduated filter. Should you need it, a third set of filter slots is provided in the kit and can be added to the holder using the supplied hex tool and longer screws.

Because it’s made from aluminum, the holder is lightweight, but it’s also very strong.

Once an adapter ring is threaded onto a lens’ filter thread, the holder is mounted by turning the small red knob until the red tab is withdrawn. Then it’s just a case of fitting the holder over the adapter ring before turning the knob in the opposite direction to move the tab back into position. It would be nice to have a sprung clip that can be pulled back and then released, but the screw-close clip is very secure. It can also be tightened sufficiently to prevent the holder from rotating, which is handy with a graduated filter.

Performance

The Kase Wolverine K9 filter holder fits easily onto an adapter ring on a lens and, as I mentioned, winding the red knob fixes it securely. Once the holder is in place, the magnetic polarizer snaps into position when it’s offered up. There’s room for the z to move around in the holder as it's the geared adapter ring that meshes with the cog/dial on the holder’s side.

Kase’s Wolverine K9 filters have a fairly wide curved chamfer at each corner. This makes them easy to slip into the filter guides and slide up or down into position. Lee Filters rectangular filters don’t have such a wide curve and as a result, they don’t slip as smoothly into position, in fact, I found they are prone to catching on their way in and need a little wiggle to send them fully home.

Verdict

The Kase Wolverine Series K9 Filter Holder is very well made. It’s light in weight and not as bulky as some other holders, but it’s also robust. The magnet makes it easy to mount the polarizer filter and the cog or dial lets you adjust the degree of polarization while you look in the viewfinder without touching any of the filters.

It’s compatible with any 2mm-thick 100mm-type filters but it works especially well with Kase’s own.

Angela has been testing camera gear from all the major manufacturers since January 2004 and has been Amateur Photographer’s Technical Editor and Head of Testing for Future Publishing’s photography portfolio (Digital Camera Magazine, PhotoPlus: The Canon Magazine, N-Photo, Practical Photoshop, Photography Week and Professional Photography magazines, as well as the Digital Camera World and TechRadar websites). She is the founder of SheClicks - a community group that encourages and supports female photographers.