Sometimes third party brands are hit or miss, but K&F Concept has never let me down. The fit is as expected, and the quality of materials is on par with the price point. What sets this particular lens apart is how rapidly you can change it out (literally in a second). The reason this is important is because if you're trying to capture something spontaneous, you don't always have the time to screw a new filter on, much-less take it off, so the interchangeability is great. That being said, the magnet isn't crazy strong, so I wouldn't advise using it for action shots if you're moving around a bunch, or maybe I need to snag their magnetic adapter ring. I haven't noticed any type of distortion or framing (like a vignette) around the border, so that's been nice as well, especially because that just adds to your workload in post. All around, I'd say it's reliable and does exactly what I needed - just make sure you understand the magnetic component before purchasing!

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.

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.

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.

But I think I'll need to go higher than 32ND, though it is of excellent quality I can't seem to get a really long exposure with these. may need to go up to 400 to see the differences.

Efficient. Great adjustment/setting control. A tad expensive. Great filter case.

It does the job BUT can't help but wonder if I should have gone with B+W's. For the price, it's good.

So I purchased both the 2-5 and 3-8 stop and they both are so clutch. I literally have no issues going out on a bright day to shoot stills or video with these two in my arsenal. I’ll be taking them down to Vegas next month so I’ll get a real test, but for now these are the best. I love the hard stop.