This is the first time I have used a variable neutral density filter and I tested it on two different lenses on two different bodies. The first was on a Canon RF 24-105 f/2.8 mounted on an R7. Having the variable density was great while taking video in an area where there was a lot of sun but some pretty deeply shadowed areas as well. The filter turns pretty easily, so it's not difficult to change the reduction in light entering the lens, making it pretty simple to keep the right exposure while maintaining a wide aperture.

The second setup I tried was a Canon RF 15-35 f/2.8 mounted on an R6 Mark II. I used this combo to take photos, and this is where I ran into the shadowing at wide apertures. I've attached three photos that show the shadowing - two at 15mm f/2.8 and one at 35mm f/2.8. The two at 15mm were taken with the variable ND set first to 2 and then at 32. You can see the shadow effect at 15mm. I went to the K&F website and their answer for this problem is to simply turn the filter until the shadows go away, which admittedly does work. However, this is subpar and the reason I gave the filter only 4 stars. When you loosen it a bit (for me it was about a third of a turn) to make the shadows go away, it makes it much more difficult to change the density of the filter since there isn't enough friction to keep the base in place while you turn the front.

Overall this filter is great if you know you're going to use it at more than 20mm or so, and especially if you're using it for a shoot where you're not moving around a lot. But if you need to shoot wider and want to keep a wide aperture, you probably want to stay away.

Finally - build quality is good and solid, the threads were smooth, and the glass is clear. I am not a professional, but I didn't notice a color change with the filter on. The only other drawback is that my lens hood doesn't work too well with the filter, and there's no good way to put a cap on the filter, so again - if you're going to be in a static place then this is great, but if you need to move around more, you might want to consider other solutions.

This K&F Concept filter is thoughtfully designed and well manufactured out of quality materials. The CNC aluminum rings are a non-reflective matte black finish that easily and smoothly screw into the filter mount of my 24mm Nikkor lens. This filter is a thin mount design and showed no signs of vignetting for this lens.

I like that the five stops of continuously variable ND values are marked on the filter, in stops, with white dots between the extreme ends that are marked for minimum and maximum effect. The adjustment ring turns very smoothly and has just the right amount of resistance so that while easy to turn, it will stay in place where you want it to. The ring only turns between the minimum and maximum points and does not over-travel. The lens mount ring is easy to grip and has some textured areas that make it easy to screw onto the lens without spinning the moving part. The filter adjustment ring has a different texture so it is easy to manipulate by feel without getting the functions confused.

I set up a camera equipped with my 24 mm and this K&F variable ND in place, on a good stout tripod. I did test exposures with no filter and then one shot at each of the demarcated positions. Six exposures taken wide open on aperture preferred automatic. I saw no issues in the final results to blame on the filter. I have owned dozens of filters in my fifty years of professional photography and this is the best filter I have ever used. It reminds me of the very expensive B&W filters that I used to prefer. That said, it is brand new and I cannot predict how well it will stand up to use and age.

The range of flexibility provided by this filter is amazing. With a variation from ND2 to ND32, it offers an impressive 1-5 f-stops of light reduction, allowing precise control over exposure levels in varying lighting conditions. This adaptability has become an integral part of my photography gear, enabling me to achieve stunning creative effects and maintain the desired shutter speed even in bright environments. The 24 - layer coating on the filter is a testament to its high - quality construction. It effectively minimises reflections, ghosting, and flare, ensuring superb image clarity and colour accuracy. The build quality is excellent, and the filter feels robust and durable. Its waterproof feature adds an extra layer of protection, making it suitable for outdoor shoots in various weather conditions without compromising performance or risking damage. The 77mm diameter makes it compatible with various lenses, offering versatility across my photography equipment. The smooth rotation allows for quick and precise changes to the light reduction level, enabling seamless adjustments while shooting. This user - friendly design significantly enhances workflow efficiency, especially in fast - paced shooting scenarios.

The is a really nice quality variable ND filter, the glass is very nice indeed and the 2-32 is perfect for me on my Z6ii for filming and photographing in reasonably bright conditions (we are lucky if we get that in the North!). Its not going to be great in super bright conditions but then where Im using it thats unlikely to be a problem. Personally I have found it perfect for dropping the ligh enough to use a nice and low F Stop. Highly recommended for any kit bag.

I ordered the 67mm size because it matches the native thread size of my largest lens with the largest diameter threads, a 70-300mm used on my full frame mirrorless camera. That lens is used almost exclusively for shooting outdoor activities including a few happening on the water in bright sunlight and the watercraft are also bright and moving quickly, kicking up a lot of water. The ultimate in lens and filter quality is not what I strive for based on my personal goals with those shoots. Landscapes and creamy waterfalls are not high on my priorities.

When I do paid shoots it's mostly of still objects under controlled conditions so I have the means and the time to get the exposure I want without filters. Looking into this K&F Nano D series it seems to be the grade and cost suitable for my realistic budget and requirements.

This ND filter will very likely stay on the lens most of the time. When it is completely threaded onto that telephoto the markings are unfortunately down at about 7 o'clock, out of sight. I will be tempted to experiment with some ultra thin shim of some sort to have the filter threads firm up when the markings are visible up top where I can quickly refer to them. The knurled grip on the ND filter is a good size for larger fingers. The rotation action of the adjustable ring is really smooth and definite, with hard stops at the extreme ends of travel at '2' and at '32' stops. There are no intermediate detents within those limits.

The packaging is a plastic case significantly larger than the filter itself which is nested in a cutout of thick soft foam. If I had a choice I would prefer the product came in a padded wallet that takes up less room in my gear bag and would drop into a jacket pocket easily. Since I probably will keep the filter on the lens it's not a deal breaker, just a preference for my habits.

I have had a semi-pro camcorder for years with a built in stepped ND filter operated by a thumb switch and that's been really handy to "dial back" the sunlight very quickly without disturbing any other settings while I continue shooting. This adjustable ND filter will add that convenience to my telephoto on the mirrorless camera.

The look and feel of this ND Filter screams quality! The transition stops turn smooth and the difference is immediate. The threads went on my camera smooth and easy. The transitions of shade provided on my camera were easy to adjust to get the right amount of natural blur. I will definitely recommend this to any content creator out there.

very good variable nd filter allows me to maintain the aperture of my lens while maintaining the blur in the background of my portraits its materials are of excellent quality I can notice it in the result of my work in no turn you notice the X that appears in others I recommend it 100%

Unlike photographers, video creators have less freedom with their shutter speed so we have to resort to ND filters like this one to keep exposure in check. This one has helped me achieve better exposure and I really love the fact that I don't have to find 'minimum' and 'maximum' because these have hard stops. Makes filming a breeze. No more looking at the lens to check if I reached the X zone.

K&F is always my go-to when it comes to filters. This variable ND filter works very well and I'm happy with the performance. As usual, the build quality is excellent and the glass is clean. No issues here!

No color cast (but you should white balance after attaching filters anyway!) and smooth rotation. Great budget or entry level stuff from K&F.