I’ve been a fan of K&F CONCEPT’s magnetic filter system ever since it came out. Magnetic filters truly changed the way I work when on hikes with non-photographers, or when traveling. Even magnetic lens caps are wonderful. Most of my lenses now have magnetic adapters. I’ve written about the system in the past
here and
here.
I was really curious when the company released two new elements to their system. Both are intriguing to say the least. Here’s my mini-review and comments.
The first is a variable ND filter (VND). It makes sense that it exists, but given that magnetic filters rotate freely, I wondered how it worked. The filter is this one:
K&F Concept 67mm Magnetic Variable ND8-ND128(3-7 Stop) Lens Filters - Nano-X - KENTFAITH.
The short of it is that it ships with a lens adapter (the magnetic part which stays permanently on the lens) which has three recesses to lock the filter in place. Of course, the filter has bumps which match those recesses. So when you mount it, it locks and stays in place, so you can rotate the front of the filter to change the attenuation. Kind of like a magnetic bayonet, in a way.
However, I have a few magnetic rings already on my lenses, and I don’t want to purchase replacements with the recesses (plus I’m not sure they’re sold stand-alone). So I mounted the VND on a regular magnetic ring. The great news is that K&F CONCEPT tuned the VND’s friction very well. It’s entirely possible to adjust the attenuation without having the whole filter move. I was seriously surprised. It just works, and that’s the best news out of this for me.
If you spin too hard, it will slip of course, but I did not expect it to work at all.
The VND can also be stacked over other filters, which is one of the nice things about those magnetic filters. It’s the same thing as when using an adapter without the recesses. All the filters in this system have the same outer diameter, except for the VND which is bigger. You also cannot mount filters to the front of it; it should be the last step in your stack. The magnets are not oriented properly to mount anything towards the front, and the size isn't right.
The VND does not create a polarizing effect in images. I also did not observe the infamous X pattern which sometimes appears with wide angle lenses. My tests also show that, like other K&F CONCEPT filters I’ve used before, there is no sharpness degradation and no color cast when using them. That’s saying something: many high-profile brands do create those casts. These filters are, optically, the best I’ve used (and I've used a few different brands).
The VND covers ND8 through ND 128, a moderate range. It is stepless as can be expected. There are markings on two opposed sides, so regardless of the orientation, you see the scale.
The other new filter is a graduated ND filter (GND) reaching ND8. That one is, in a way, even more surprising. GNDs are normally squares or rectangles, and the transition can be adjusted precisely and at will via a big and complex mounting apparatus. This GND is a magnetic circle with the transition close to the center. I was curious to see how I could use it.
It turns out that the filter does force the user to compose with the filter. Transitions, horizon lines, etc, should be taken into account when using the filter. That doesn’t mean the horizon should be in the center, but that you need to think about your end result a bit more. One nice aspect of this filter is that it can so easily be rotated, it can serve with irregular scenery also, like this NASA building below.
While the VND filter is bigger than other K&F CONCEPT magnetic filters, the GND is the same size.
The GND ships with a kit, including an adapter ring, ND8/64/1000 regular ND filters, and a great case. This case is improved from what the company used to ship. It has a zipper, but also a magnetic flap which makes it quicker to reach inside. It also has a belt loop with velcro, and a metal loop to clip it somewhere.
So, long story short, I’ve been a fan of K&F CONCEPT’s filters for a while, and I truly love these new additions to their lineup. Both are optically better than what we ought to expect, both are easy to use, and both make it simpler and easier to include filters in my workflow.
I hope this was useful! Here are a few examples of the filters in use:
VND
VND
No filter
VND 16
VND 32
VND 64
VND 128
No filter
GND poorly oriented (intentionally)
GND well oriented (and not horizontal)
GND
Last edited by bdery; 04-04-2023 at 12:51 PM.