Initially, I did not like the fact that when I was trying to rotate to change stops, the whole body of the filter was rotating, but then I realized that there is a special lock of the filter when you place it on a magnet ring locking body of the filter and allow easy rotation of the adjustment ring.
The overall quality of the filter is superb. Great color and sharpness. No X pattern.

I received this for evaluation and thought that I would give it a try with a Fujifilm X-T3 mirrorless.

Generally, I run a UV filter on my lenses for a bit more protection from the elements (I like to shoot at the beach a lot and the salt air can easily leave a coating on the lens). But when I want to achieve slower shutter speeds to soften waves, I utilize a series of ND filters. This requires me to add a filter holder in front of the lens and then slide my ND filter of choice into the filter holder.

This set up makes the whole process so much easier. I can attach the included magnetic holder into my 18-55mm zoom lens. Then, when I want to attach the variable ND filter, I reach into my bag, pull this baby out and let the magnet attach it to the lens. It spins freely so that I can dial in the amount of ND that I want. No more fussing with multiple filters stacked in a filter holder. That makes me happy and leaves less room for error, more space in my camera bag, and less fumbling at the beach with the wind and sand blowing.

It is a tad pricey to me but the overall improvement of time, effort, and ease of use make up for the price.

Serves good for my Sony 16-35 F4. No image degradation as far as I can see even at 16mm

I’ve hardly taken it off my camera since I tested it. I just loved it. I didn’t notice any color shift but the variable ND has been handy. The magnet is decent in my opinion. It’s the best I’ve seen as they all fall off at some point. This one only fell off when I was storing in my bad and had the lens cover on. It hit the case and fell off. I snapped it back on and and it’s been in place since. I totally forgot that it’s magnetic till it fell off. I believe that’s a good report. I really can’t complain. It’s definitely a good product.

I love this filter. I can dial in how much/many stops of light reduction I want with just one filter vs carrying a bunch in my camera bag. Mounts to my nikon lense no problem and works well for long daytime exposures.

Over all build quality and design is very good but Having vignetting with 24mm lens, Best to use with higher focal length than 24mm

This is a nice filter. It works as expected without a color shift of X-Pattern.

The magnetic attachment is pretty cool. It allows easy changing of filters via a small magnetic ring. I don't currently own any of the other K&F magnetic filters, but I can see the value of the eco-system. I like that i can easily add or remove an ND filter without screwing/unscrewing. The magnet does seems a bit weak, so I'm curious to see if I'll run into any issues of the filter inadvertantly coming off. I'll report back if I have any concerns after road testing it more.

It rotates smoothly. I do wish it had a know like the 1/4 diffusion ND filter does. That was a brilliant design.

It comes in a sturdy clear plastic case.

For a variable ND filter, I'm happy with this.

This is a good adjustable neutral density filter with no problems I can see. It uses K&F's special coatings to help repel dust, water and fingerprints. This filter has a magnetic attachment system, there is a magnetic ring (with no glass in it) you screw onto your lens. Then whenever you want to use the ND filter you just pop it on and pull it off magnetically, making it easy to change. The system seems to work well, but it's the only one of their filters I have which features it. By rotating the filter you can go from ND2 to ND32, or 1-5 stops.

A lot of people wonder what this kind of filter is for, basically it lets you get some different effects when you are shooting in direct sunlight. For example, you can open the F-Stop of your lens all the way to get a shallow depth of field effect, then use the ND filter to darken the image back down so it is exposed right. Another common use is so you can shoot with longer shutter speeds in bright light. This will allow you to get that effect where moving water has a soft motion blur on it by setting a longer shutter speed and adjusting the exposure with the filter. It's also very handy for shooting video in bright light. Using a high F-stop and shutter speed for this can give you a video that has no motion blur and appears to stutter when the camera pans. The ND filter can allow you to shoot with longer exposures which will give motion blur and a smoother more cinematic look when panning.

So overall a very useful filter to have if you do videos or photos outdoors in bright sunlight.

I'm really digging these new filters that K&F are releasing. The magnetic filter system is a great idea for strong ND filters because I often need to compose my shot without the ND filter attached (because it's much easier to see through the lens without it) and then attach it to take the shot; being able to simply snap the filter on to the front of the lens takes a lot of the hassle out of detaching and reattaching the filter.

The optical quality is superb, with excellent clarity and barely any color cast. The build quality of the metal rings is solid; they are smoothly machined with smooth edges and nice knurling. The rotating ND filter turns smoothly, with hard stops at either end of the spectrum so you know when you've reached the limits.

The magnetic attachment holds the filter in place snugly but it's probably best used in controlled tripod setups where you know the lens won't be bumped; I definitely wouldn't use this in any kind of crowd situation where someone or something could knock the filter off, because it wouldn't take much of a bump to cause this to happen.

There's no lens cap included, presumably because the extra weight of it would make the filter too heavy for the magnets to comfortably hold. K&F does make a magnetic lens cap, which I got with a different K&F filter set, but it doesn't fit on the outside of the ND filter because the outer ring is larger than 77mm. However, the magnetic lens cap DOES fit on the inner ring so you could use it when you're not using the ND filter. As far as I can tell you can't buy the magnetic lens cap by itself, only bundled with other filters.

This filter is easily comparable in quality to those made by Tiffen. It's fairly priced, and I would definitely recommend it for tripod-based landscape photography.

Having a lot of camera equipment such as strobe lights, key lights, speedlights, umbrella, lenses, extra batteries, tripods and many other things. Wow I can't believe I use so many things just to get the photos that I want. Adding lens filter on top of all these is just.... what a hassle.

This variable ND filter and magnetic adapter ring kit are one step in the right direction. It's very easy to put on the magnetic adapter ring kit. Once the ring kit is secured, attaching the variable ND filter is very easy. It's a convenience that this filter god from ND2 - N32, 5 stops.

Hint: Make sure you pick the right filter size. If you have a collection of lenses with varying sizes, pick a higher size. You can buy a separate adapter to downsize.