Filters have great advantage to landscape photographers, but they also have some drawbacks. The first drawback is that they are an added layer of complexity on the photographic process, they can be fiddly to use and they can slow the process down. The light on a landscape is usually in constant flux and any delays imposed by adding equipment to your camera might mean you miss the crucial moment and fail to get the shot you were chasing. So when it comes to filters - simple is good. The other drawback is the cost. The filter accessory market used to be dominated by a couple of well known high-end brands (Lee, Heliopan and B+W) and several (slightly) cheaper options (Cokin, Hoya and Tiffen), but some of the cheaper filters were well known for introducing the dreaded colour-cast on photos and were not seen as a viable option for the serious photographer.
Fortunately the filter market is very different these days and more competitive. Companies like K&F, Gobe/Urth, Neweer, Nisi, Moment and PolarPro produce great filters, including models for action cameras and drones. More importantly these budget filters do not suffer from the quality issues of the previous generation of cheap filters and they offer a great opportunity for any photographer not hung up on brand names. All of which brings me around to the K&F Nano series.
There are several ways of mounting a filter to a camera lens, all of which have inherent advantages and disadvantages. The K&F Nano kit does away with the traditional bracket and clamp style or screw-in type and instead uses a magnetic system. The package I was sent for review is the 72mm Nano Filter Kit which includes a UV filter, a Circular Polariser and an ND1000. These attach to a slimline mounting bezel which you screw onto the lens in the usual way.
The principle advantage of a magnetic filter system like this is the speed with which you can add or remove them. This ease of use and speed means you're more likely to experiment with your photographic compositions since you're not weighing up the hassle of screwing on a bracket, inserting a filter and lining it up and then taking it all off again. If the mood takes you, you can just clip an ND1000 onto the filter in a second and take it off again as easily.
As with previous K&F filters that I have tested, I had no problems with colour cast or distortion. The Nano coating that K&F used is a protective one that is resistant to scratches and fingerprints. This is a big deal for me as I do not have a great track record for looking after my photographic kit and I am certainly not one of those photographers that babies their kit and handles it with clean-room gloves. The ND1000 supplied with this kit performed as well as the K&F Concept Square Filter System and ND1000 Pro Filter that I previously reviewed here.
When I tested the circular polariser I was briefly puzzled that there was no inner bezel to twist for alignment to the sun. Then I slapped myself on the forehead and simply rotated the filter on its magnetic mount to achieve the desired effect. (Sidenote: there aren't currently any ND-grads in K&F's magnetic filter range, but I see no reason why they couldn't work the same way as the circular polariser). As with the ND filter I saw no colour cast in evidence and was thankful for the Nano coating, as touching the filter is inevitable when it's magnetic. The third filter in this pack is a UV filter which was optically clear, but of limited use. I only ever use UV filters to protect the main lens (from damage or splashes) not because I feel they make any significant difference to my photographs.
The filters are supplied in a neat little protective zip bag, which has four slots but could easily accommodate more of these filters if you decided to extend your collection beyond the three supplied with the kit.
The advantage of a magnetic mount system is its obvious simplicity and ease of use, but the disadvantage of this system is that it is not as flexible as a bracket system. You can only use this set of filters on the thread size its specified for and would therefore need to buy additional sets for any other lenses you use for your landscape photography. Theoretically you could use a step-up/down ring but there might be issues with vignetting.
For someone like me who has one main landscape lens (I use the XF10-24mm for the majority of my shots), then these magnetic filters are a great option. I can leave the mounting bezel on the camera and still attach the filters and the lens hood. I can even switch out between ND1000 and polariser without removing the lens hood which is another added convenience. The filters supplied in this kit would serve well as a great starter-filter set for someone who's beginning to explore more technical aspects of photography such as long exposure and are a lot less fiddly to use than the traditional bracket system.