Fits the description. Thanks to the seller.

Works well with my a6400 + tamron 17-70 combo! Now I can shoot Slog2 with low ISO especially during sunny days.

Very solid unit and performance is excellent

This neutral filter works great. I only use it outside when it's sunny, and I always require the minimum nd2 of the filter (no need to buy one that starts at nd0). At the same time, nd400 is the perfect maximum so that even parts of the sky at midday don't look overexposed. Like most variable density neutral filters, since they are just two polarizers, you can vary it 360°, but you shouldn't go over nd400 even if you can. In the indicated range you will never find any problems with vignetting or X-shading. And it's great that the quality of the (nano)polarizers allows this wide range without any problems and everything is homogeneous. In theory, the only problem with this filter (compared to 200€ polarizers like the PolarPro) is the possible slight color deviation towards a small green tint for blacks. I don't really notice it at all, so it's not a problem for me. Oh, and like any variable density neutral filter, since it has two polarizers, you can use it as a single polarizer (see video), so there's no need to buy the 2-in-1 version. By just unscrewing the filter a little you'll get a moment when reflections are avoided. Obviously, like any polarizer, it will only work for reflections at the Brewster angle (about 56° for most glasses), which uses the physical phenomenon of polarization by reflection (at a certain angle the reflected light comes out linearly polarized). And one last thing, the fact that it has the orange piece that makes it more "fancy" when rotating, that is, adjusting the nd of the filter, means that you can't use, for example, a lens hood with the filter. But it can be easily removed with a torx screwdriver (t1, t2 or t3, I don't know which).

The K&F Concept Nano-X Variable ND Filter has been an awesome addition to my photography gear. With a range of ND2 to ND400, I have the flexibility to adjust exposure in various light conditions without needing to constantly change filters. I’ve tried it out on several outdoor shoots and love how it allows me to control the effect on water or in the sky, giving me that professional touch I always look for in my landscape photos. The build quality is excellent, and the glass is very sharp – I haven’t noticed any vignetting or loss of detail, even at the highest density levels. Additionally, the rotation of the filter is very smooth, allowing me to fine-tune it without any issues. Another thing I’ve been pleasantly surprised by is how thin and lightweight it is. It doesn’t add any weight to my camera and takes up almost no space in my bag, so I can carry it everywhere without a second thought. I also appreciate the anti-reflective coating, which really helps reduce flare and improve contrast, especially in bright conditions. In summary, I highly recommend the K&F Nano-X filter to anyone who wants quality, control and flexibility in their photos. It is an essential tool for any outdoor photographer looking to take their images to the next level. Very pleased with this purchase!

I was afraid I would have problems being a variable ND with rare effects, and zero problems. Neither on the corners, nor at ND400, the truth is that a pleasant surprise for its price. It may have a little green tint, but with a correction of nothing in the Premiere I fixed it, between 5 and 10 points on the dye tab towards magenta and you're done. Highly recommended, you just need to have a cap like the ND2 and ND32 models that are the ones I usually use.

If you know who this brand cap is it will fit this filter. I just so happen purchase much lens from a buyer who included this cap with it and it totally fits perfectly. But your normal cap will not.

Anyway I love the filter it does a great job just be aware of the cross viniette.

I got to try this filter for my Sigma 17-50, and the result is really amazing. The product looks great in its really great quality packaging and easy to carry in your bag.
The photographic performance is at a high level at a low price. I find the tongue very interesting, it allows you to have better grip during work.

I purchased the K&F Concept Variable ND Filter Neutral Density ND2-ND400 (9 stops) with Rotating Ring to be able to use a fast ND with different densities.
The packaging is very well done, solid and space-saving container. The glass filter is light and the ring to increase/decrease the density is smooth. It has no end stop lock.

To test it best I tried it with three different lenses on the Nikon D750 camera (full frame): 20mm, 35mm and 85mm.
- 20mm: in the photos taken with the filter there is no particular loss of sharpness, it introduces a slight hot dominant that can be easily solved in post-production. As far as the X-shape problem is concerned, it is quite marked using the filter beyond the marked ring. Instead, using it within the marked marking, the problem is little present. See image attached.
- 35mm: in the photos taken with the filter there is no particular loss of sharpness, it introduces a slight hot dominant that can be easily solved in post-production. As far as the problem is concerned, X-shape is not as marked as in the previous one, but there is a vignetting especially in the use with maximum effect. See image attached.
- 85mm: in the photos taken with the filter there is no particular loss of sharpness, it introduces a slight hot dominant that can be easily solved in post-production. As far as the X-shape and vignetting problem are concerned, they are not relevant. See image attached.

Optically, the filter is well made and provides excellent results, but I would have preferred a start and end run with lock in order to avoid possible mistakes. Also considering that K&F produces other types of filters but with magnetic connection, I think it could be a further plus for this filter.

The price/performance ratio is correct based on the performance provided.

I attach more photos of the packaging and two shots to the sea.

Quality, Glass, stop selection. Excellent filter optically superior, image quality, and light control superb.