Kase Wolverine Magnetic Filters
Kase Wolverine Magnetic Filter - 112mm Circular Polariser
Most of my previous F-mount lenses tended to use 77mm filters or smaller with adapter rings as necessary, but my newly acquired Nikon Z 24-70 f/2.8S zoom required 82mm filters and the 14-24 f2.8S lens needed 112mm filters in an oversized threaded lens hood - the previous AF-S 14-24 f2.8G lens would not accept screw filters at all so this was a welcome change.
I have tried a number of filter systems using square and rectangular filters in dedicated filter holders but I always found setting up the various adapters, stepping rings and filters to be a bit of a faff to be honest and tended not to use them too frequently especially now that digital post processing has made my graduated ND filters somewhat obsolete. I have drawers full of redundant holders that are no longer in use. Similarly, the thought of multiple stepping rings and having to constantly screw on and unscrew circular filters did not hold much appeal.
The arrival of the Nikon Z 14-24 f2.8S lens gave a new alternative. The lens arrives with two lens hoods, a standard size HB-96 hood and an oversized HB-97 hood with an integrated 112mm filter thread. The hood simply bayonets on and off the lens so is easy to fit and remove and it is made from lightweight plastic so is easy to carry around in the camera bag. The hood also fits onto the Nikon Z 24-70 f2.8S, Z 70-200 f2.8S and Z 14-30 f4S lenses so could be used as a quick fit filter system, albeit without being able to use the dedicated lens hoods for those lenses.
I had watched YouTube videos from Hudson Henry, Nigel Danson and James Brew detailing how they had switched to the Kase Wolverine Magnetic Circular filters and considering how Kase had released a 112mm version of the filters for use with the Nikon Z 14-24 f/2.8 S, I decided to give them a go.
Rather than jump straight in and buy the 112mm professional kit (which was out of stock anyway) I decided to try the 112mm Wolverine magnetic circular polariser (CPL) and the 10 stop ND filter. The filters arrived the next day. Even though I had seen many reviews I was still surprised by how thin and light the filters were. The filters were so thin that I initially assumed that Kase had forgotten to include the adapter ring, but on closer inspection realised that the filter was already magnetically attached.
The adapter ring was extremely easy to install in the Nikon HB-97 lens hood as there are a number of notches around the ring to enable you to rotate the ring and screw in to the hood. Once the ring was fitted into the hood, installing the filter was simplicity itself, just hold the filter up towards the ring and the magnets and recessed design ensure that the filter installs centrally in the hood. The magnets appear quite strong and it is unlikely that the filter will fall off during normal use.
The circular polariser is extremely thin - possibly because there is no separate rotating section - the filter simply turns against the adapter ring. The friction between the two items creates a slight scraping sound but so far this does not appear to have caused any scratching of the metal sections and no dust generation. The friction does initially make it seem that the CPL is sticking compared to the smoother rotation of a normal polarising filter but this is something that you quickly get used to and the convenience of magnetically attaching the filter far outweighs any downside.
The 10 stop ND filter is even thinner and lighter. In the short time I have had the filter there is no obvious colour cast. Some reviews identify a slight green tint that is easily correctible using Lightroom or other post processing software but I couldn’t detect any specific colour changes using my iMac 27” 5K monitor. Lightroom colour picker values were in good agreement showing only +3 change in tint between photographs taken without and with the filter respectively.
The exposure filtration factor also appears to be fairly close to the declared 10 stops. Photographs taken at f/2.8, ISO100 and with shutter speeds of 1/250th second without filter and 3 seconds with filter show good agreement in Lightroom indicating the actual filtration value is approximately 9.67 stops. Using the 10 stop factor to calculate exposure may cause slight overexposure but ⅓ stop is not particularly significant.
Sharpness of the images does not appear to be affected using either of the filters with the lenses shown above on either my Z6 or Z7 ii cameras. All of the filters are made from B270 Schott optical glass and coated on both sides to give a hydrophobic, shock resistant filter that are resistant to corrosion and mildew formation. The hydrophobic coating minimises water spots and makes cleaning the filters easy.
One pleasant surprise, the 10 stop ND filter appears black to the eye, unless holding up to a strong light source, but the Z6 and Z7ii cameras both managed to meter correctly with the filter attached and even increased the brightness of the EVF to allow the scene to be composed and focussed. This would not have been possible using the optical viewfinder of my previous DSLRs.
There are reports on the internet that the Nikon HB-97 lens hood allows light leakage that prevents its use with strong ND filters and this was something I was concerned with as I wanted to get more and more into long exposure time photography. I haven’t done any scientific testing but conducted a quick experiment.
I placed the camera on a sunlit window sill facing into a fairly dim room so that the scene taken was pretty dark. The camera was arranged so that the sunlight was shining on the top of the 14-24mm lens from behind the camera with the lens hood bathed in bright sunshine from above and behind, including the notch where the internet claims said the hood was particularly vulnerable to light leakage. Attaching the filter and taking a 30 seconds exposure I expected to see bright areas corresponding to light leakage, but was surprised to find a perfectly exposed photograph with no evidence of any overexposed areas or areas lacking contrast. In my case, these claims appear not to be an issue.
Overall, the filters are superb quality and optical performance is excellent. The glass is toughened to resist breakage and although not indestructible the filters are designed to survive occasional drops. I am not planning to test this (unsurprisingly) so will defer to the numerous internet reviews that vouch for this fact.
The filters are a joy to use and I find myself using them more frequently that with previous systems. I will continue to see how they perform, particularly looking out for light leakage with the Nikon lens hood in case I need to attack the hood with a piece of gaffer tape. I am now looking to add further ND filters.
I may also look into getting an adapter ring for my AF-S 500 f/5.6 PF lens (95mm to 112mm) to allow the filters to be fitted to this lens, particularly the CPL filter. Alternatively I might buy the 95mm kit so I can continue to use the lens hood supplied with the telephoto. Or both !!