Have been a long-time purchase of different filters from K&F for Fujifilm and it's one of our go-to brands. They do a great job with the filters and this one was for the Viltrox 75mm. Just make sure you know what your thread size is so you get the right filter. Good quality as usual and works as expected for a variable filter!

The filter I always stack are CP and ND, and now I finally have them in 1 filter!
ND and CP effects are both very nice, and the filter is built solid.
K&F makes some really nice stuff.
All threads are smooth and the filter is easy to install and adjust.
It's been on the front of my favorite lens since I got it, and it makes my vids look professional.

With no visible X or color cast, I'd say this is a good VND filter.

This CPL ND filter is awesome. The build quality on this filter is immaculate. The threading is all metal and just glides. Theres no annoying X pattern on the ND side of things and it does an excellent job at getting rid of unwanted reflections as well. The optics are also excellent there is no dip in quality and the coatings really help to cut out glare and purple fringing.

I'm just an amateur photographer, but I really like this filter. It's like having two filters in one. The adjustable ND filter means that I don't have to keep switching out filters when taking photos. The filter is well made and works smoothly. It comes with a sturdy plastic case to keep the filter in when not in use.

I'm positive I picked the proper size filter but it came with a smaller one. Since I only have one lens that I can adapt it to I won't be able to use it with the lenses I had intended to use it with. I like the concept of the combined ND and CPL Filter I know I can stack filters to get the same result. But it would have been nice to have the two things in just one lens filter. The polarized lens It's very often handy to have for longer exposures Regardless that It's not the size I wanted you should be happy with the results you could get from this combination. I have always been happy with K&F filters

I picked this up to use with my Sony A6400 with Sigma 30mm 1.4. This is my go-to set-up for taking pictures of the family/kids but wanted this filter to be able to shoot wide-ish open during the middle of the day. So, basically it does exactly what it's supposed to do; there wasn't any noticeable distortion, softening or color changes, and it was able to drop my shutter speed enough to not blow out the highlights. What I really like is the knobs that allow you to change the ND intensity quickly - this is an absolute life-saver for shooting toddlers and young kids, as they are the fastest things on the planet and they're not going to wait for you to change the filter on your camera. The only negative is the need to potentially get a new lens cap as the filter diameter is larger than the lens cap diameter. This is addressed in the description, but it's just something to keep in mind. Overall though, it's a nice filter.

I am not a professional photographer but I do take a lot of pictures when I travel. Often I see something and have to reach into the camera bag, screw a filter on, and take the picture. This makes things a little more convenient. I can carry less filters when I travel since this single filter is adjustable and does the work of several filters.

This screwed flawlessly onto the end of my Canon lens. I like that I can simply dial in the filter setting that I need and I am ready to go in no time. I took several shots and I was totally pleased with the results.

This one will be in my lighter travel bag when I am out and about.

From the golden outer packaging comes a microfiber cloth wrapped in foil and the actual filter box. Inside is a filter that is oversized and heavy for the screw-in size. I have the filter in screw-in size 82mm and am testing it on the Leica Vario-Elmarit-SL 2.8/24-70 with the Leica SL2s.

The mount has a grooved grip ring for screwing in, which protrudes about 1 cm over the filter mount. This makes it easy to grip and screw in or out. There is no fiddling when changing the filter and no dealing with filter clamps when the filter is stuck! The manufacturing quality of the mount is excellent. The entire front frame of the filter has to be twisted to adjust the strength of the polarization. The screw-in knurled ring must be held in place because the rotation of the polarizing filter is difficult. The difficulty is not a design or manufacturing defect, but is for the 2nd function of the Filter is required, namely the darkening from factor 2 to 32, which is adjusted in the front part of the filter holder with 2 relatively large and easy-to-grip levers. If the polarizing filter adjustment were smoother, it would rotate with the ND adjustment.

The overhang of the filter holder makes a larger filter glass possible than with conventional screw-in filters, so that the thick filter does not vignette even at a 24mm focal length. The filter glass is visibly multi-layer coated; a water-repellent nano coating is applied to the front. The original lens cap can be snapped into the filter! All of this gives the impression of a very careful and well-considered design.

Polarizing and ND filters work as usual. There is no particular susceptibility to reflections and stray light. I cannot detect any impairment of the sharpness or an explicit color cast of the lenses. Of course, using the polarizing filter outdoors causes intentional color changes by filtering out the sky reflections, which means that, for example, green plants have a lower blue and a higher yellow component.

One basic problem with using the polarizing filter with mirrorless system cameras remains: except for reflections aimed at at an angle, the strength of the filter effect is practically undetectable on the OLED viewfinders. Landscape photographers who prefer polarizing filters are therefore recommended to use a DSLR with a mirror, in whose natural viewfinder image even small rotations of the polarizing filter are clearly visible. But this is not a fault of this filter, but rather affects polarizing filters in general.

Conclusion: A very carefully and practically constructed double filter at a very attractive price in comparison!

This K&F Concept 67mm Variable Fader ND and CPL Lens Filter is a really good, adaptable lens filter that combines two common lens filters into one with a variable adjustment. I was immediately impressed by how smooth the filter was. The adjustment itself is smooth and tight and the actual transition of the image is smooth to match it. The quality seems very good overall and it threaded smoothly onto my lens.

One note, I did not realize ahead of time is that you will need a different lens cap to fit on with the new filter. I have a 67mm lens and ordered the 67mm lens filter. My original lens cap does not fit on the new filter, so I now need a 72mm lens cap to go on this. There is a chart buried in the product description that shows the adapted lens cap size for each filter size but it is essentially a standard size up from whatever filter size you order. These are fairly inexpensive and easy to come by, but it would have been nice to include a corresponding lens cap with the product.

There are many applications where this comes in very handy and can allow you to get unique shots that would be difficult or impossible without this. Some applications would include scenarios like:
- mixed lighting conditions with bright and shadowed areas to balance the exposure;
- removing glare and reflections on reflective surfaces like water;
- landscape photography to reduce glare and improve the appearance of the sky; and
- taking long exposures in brighter conditions without overexposure.

The filter set to minimum does darken the image slightly. Also hoods and other accessories do not fit with this filter, so there are instances where you'll want this off the camera, such as low-light conditions. Still, this is a great all around filter that is worth having in your bag.

Overall I am very happy with the quality and function of this K&F Concept filter and would highly recommend it. Do keep in mind that you'll need a larger lens cap diameter than the size you order, but other than that I think this is a very worthwhile pick.