Consequently, we’ll need to judge this filter set on two aspects: the functionality of its magnetic attachment system, and the quality of its VND filters (and filters in general). What Do You Get? J. Matthew Gore Each filter comes with a threaded ring that screws into your camera lens just like any other filter you've used in the past. The difference is it's just a metal ring that does nothing until you attach a filter to the ring using it's magnetic system. Freewell also offers the option to use a UV filter as the magnetic ring for it's system but I didn't use one in this review. K&F Concept’s lens adapters have two advantages. The first is that they are quite slim, measuring at only 2mm once installed. The second, and possibly most important, is that the adapter lets the user attach regular lens caps. These advantages mean they can remain permanently in place on a lens. Non-magnetized, threaded lenses, however, are not compatible. This is because neither the magnetic filters nor the base ring offer outward facing threads. Color accuracy and sharpness

These filters feel good to use. Yes, you need to be careful as with any type of photography filter, but you don’t have to worry as much as when you’d use all glass square / rectangular ones. They’re light but don’t feel hollow. Their magnetic capabilities make them really easy to swap around when you’re out in the field. No more unscrewing and fumbling with filter threads on location. Just set your base ring to your lens, and from then on, it’s just magnets doing their magic. And my testing showed that these types of artifacts occur reliably with ALL of my VND filters. I shot this scene, first with no filter: J. Matthew GoreCompleting this analysis, K&F Concept’s ND100, 10-stops neutral density filter has no measurable effect on color or sharpness. Optical Test Summary In colder temps and time restricting locations, being able to just pull off a filter and slap another one on saves a ton of time. It would save your numb hands from trying to thread on and off filters, like you’ve had to do in the past.

Today we are taking a look at K&F Concept’s line of magnetic filters. Called the Nano-Series, this system currently sells as a kit including a lens adapter, a UV filter (doubling as an extra lens adapter), a CPL and an ND 1000 filter. Description of The System In recent years, we’ve reviewed two nice sets of VND filters ( PolarPro and Moment) and a set of magnetic filters ( K&F Concept), but this is the first magnetic VND filter that we’ve worked with.However, if you want to shoot with a VND filter, your first need to snap the VND base filter into the inner filter slot in the base ring on the lens. Then, you flip one of the VND filters so that the “VND” text on the ring is facing you, and snap that on top of the base ring on the lens. Remove the base ring filter, and there’s now one pane of polarized glass (which is effectively a circular polarizer is). There’s always a possibility that adding a couple pieces of flat glass in front of your expensive optics will degrade your resolution, but I didn’t find that to be the case with these filters. Having tested on my 42 megapixel A7RIII and some of my sharpest lenses, there was no visible loss in resolution in the center or edges of the frame when using the Freewell filters compared to test shots with no filters. Cross Polarization Problems Contrary to regular polarizers, the CPL has no moving parts. It rotates simply by moving on the adapter. This does generate a small friction noise. Rotating a CPL filter with the M2 system is a straightforward process. We’ve made it simple and intuitive to adjust the polarizer to achieve your desired effect.