ND filters are essential if you're going to be shooting with anything that may involve bright outdoors. For example, you can use an ND filters indoors to lower the exposure of an outdoor window, and then you can add lights to bring the exposure back up of your subject, that way both are perfectly exposed. K&F Concept made the interesting design choice to add a putter, and I'm all for it. It makes the function of changing the ND value a lot easier to do than the traditional way, mostly because sometimes I've tried to rotate a part of the filter but it wasn't the part that actually controlled the ND value. Overall, I really recommend this filter. It's fantastic!

The filter is huge.
7.4mm thick and 159gr weight, designed probably more for outdoor use.
Multi coated surface (28 layers), filter made of glass, scratch resistant, waterproof,....

You get a shock when you hold it in your hand for the first time.
There is a scale in the front that shows the approximate values, all of this is easy to grip on the frame itself or adjustable with the small handle that is screwed on.

The filter rotates completely, i.e. at the end / ND1000 comes a tiny step before it goes up again. Because there is no stopper, you have to be quite precise to get the highest ND value.
Even though it is of course the common design of these filters, I don't find this particularly practical or easy to adjust. You really have to pay attention, the scale doesn't really help there because the highest effect comes after the ""1000ND"" entry. And a little bit of rotation further, the ND decreases again.

Optically everything is ok, I could not notice any major / disturbing color changes - at least nothing that one would not have expected with this type of filter.
With and without the filter, the image remains sharp.

The whole thing comes in a plastic bag, where the filter sits loosely inside, without any further cover - again, I'm rather the friend of the closable plastic covers, but ok.

For 80 euros you get a good tool at hand.
For me, not the optimum, but that is complaining at a high level.

I tested the variable gray filter from K&F on a Tamron 28-200mm F/2.8-5.6 DI III RXD lens and a Sony SEL-20F18G, on a neutral white background.
Since I already use fixed ND filters from K&F and am quite satisfied with them, I was curious how this variable filter would perform.

Advantages of the variable gray filter from K&F:
- Significantly less expensive than purchasing multiple fixed density filters.
- Takes up less space and weight.
- When filming, among other things, smooth aperture transitions can be realized without post-processing.
- Pleasant feel.
- Handle for adjusting very well solved.

My conclusion: The filter from K&F achieves good results especially at low stops between 1.5 and 4 f-stops. Beyond that, however, the uneven light distribution at the edges of the image increases. This becomes more noticeable the shorter (e.g. at 20mm) the focal length is. At 10 f-stops, the X-effect then also becomes visible. The color fidelity is not really neutral and has a slight yellow cast, but can be easily corrected afterwards via the white balance in RAW images. An assessment of the set density via the scale on the filter is only roughly possible, which makes it almost impossible to calculate the exposure times manually. However, modern cameras like the Sony a7 series can reliably calculate the exposure time through the filter. To be fair, it must also be said that the aforementioned weaknesses occur to a greater or lesser extent with every variable gray filter. Therefore, my recommendation for ambitious photographers is to rather rely on ND filters with fixed density. In the range of 1.5 to 4 f-stops, however, the variable filter from K&F is quite usable for qualitatively good photo shots. Especially for filmmakers, the K&F should be an attractive filter, at a reasonable price. In my opinion, the disadvantages are less important here. The processing is successful in every respect. The filter can be operated well, without accidentally touching the glasses with your fingers.

The package containing the K&F Concept Nano X-Series Variable ND Filter ND3-ND1000 Neutral Density Filter 67mm (1.5-10 f-stops) was delivered quickly and securely packaged. I love photography and was delighted to be able to test this filter. The black outer box containing the filter was covered with a plastic film to prevent any moisture from penetrating. The filter itself comes in a high-quality plastic case. The flap of the case is magnetic, so there's no unnecessary fiddling around to get to the filter. Very practical: The filter can be easily lifted out using a strap. The whole thing looks really classy and would also make a great gift for an amateur photographer. The filter itself is made of Japanese optical glass with a 28-layer nano-coating on both sides, which is supposed to prevent a certain amount of lens reflection and, of course, glare from various light sources. According to the manufacturer, the ND filter is waterproof, oil-proof, and dustproof, which is particularly useful in nature and when hiking. I have the feeling that the filter is very robust. It weighs 45 g with a 67 mm lens. Of course, the price is correspondingly reasonable. The filter frame is made of aircraft-grade aluminum, has an ultra-wide-angle design, and is just 7.4 mm thick. Anyone like me who has always used several different darker neutral density filters will appreciate the fact that they only need one filter. I use neutral density filters primarily for photographs of water by a lake, flowing water, or waterfalls. They are also fantastic for long-exposure shots of places where you would like to photograph without people. The function of this adjustable filter is quite simple. Operate the practical slider, and the filter darkens or brightens as needed (see photos). This makes it easy to try out different settings and effects without having to constantly change filters. However, I must also mention that you can't attach the lens hood to this filter because the slider gets in the way. It's a bit impractical, but hey, you can't have everything... Conclusion: The price is within the normal range for this type of aperture adjustability. Sure, there are cheaper options, but the K&F filter is built with a somewhat higher quality. The results are certainly impressive. Since I'm not a professional but simply enjoy photography, this filter is actually a great companion for me and I can recommend it with a clear conscience. As a product tester, I study each product I test very intensively, putting it through its paces, so to speak, and only give reviews that I can fully stand behind. I hope my review was helpful to you.

Packaging and shipping

ordered this K&F Nano X-Series Variable ND Filter ND3-ND1000 (52mm) for my "always-on" lens. The filter arrived at home very elegantly packaged, including a leather case. I tested the filter on my 28/2.8; it screwed on without any problems, and adjusting the aperture worked perfectly thanks to the very pleasant resistance and the integrated nosepiece. The filter produces neither color casts nor image aberrations. The ND3-ND1000 is a perfect companion for me from wide-aperture photography in daylight/sunshine to long exposures, so it's very versatile. I can definitely recommend this filter due to its excellent quality (workmanship/image quality). Best regards, Holgi

K&F Concept filters are always very high quality. I've never owned a neutral density filter before, so I'm excited to be able to test this one. The packaging itself is very high quality, and the included leather case is very nice and sturdy. The filter can be easily pulled out using the strap. The case flap is magnetic. The small orange handle makes it very easy to adjust the filter. The effect is amazing. It helps you easily adjust the exposure in a wide variety of lighting situations. I mainly use it in lighting situations where I want to photograph with an open aperture and the daylight is too strong. The colors in the image are not negatively affected by the filter. Great filter at a reasonable price. I give it 5 stars.

already have a variable ND filter, but I'm not satisfied with it because the dial is stiff and the results don't meet my expectations. Having already given up on ND filters, I came across a product review for this K+F filter, which impressed me so much that I ordered this filter for my new lens (Tamron 35-150mm f/2.8f). The packaging (high-quality cardboard with a magnetic holder), the gold-decorated insert, and the leather storage case gradually convinced me that this is a high-quality product. The filter arrived dust-free, has visible coatings, and a really easy-to-use dial for dynamically adjusting the filter. The screw thread is flawless, and the initial results are significantly better than my attempts with the more basic filter. I'm satisfied, but I expect this level of performance even at such a high price. I highly recommend it!

The filters from K&F Concept are always very high quality. I have not yet had a gray filter. Therefore, I am pleased to be able to test this one.

Even the packaging is very high quality and the included leather bag is very nice and sturdy. The filter can be pulled out quite easily by the strap. The flap of the bag is magnetic.

Through the small orange handle, the filter can be adjusted steplessly very easily. The effect is amazing. It helps in a variety of lighting situations to adjust the exposure comfortably. I use it mainly in light situations where I want to shoot with an open aperture and the daylight is too strong for that. The colors in the image are not negatively affected by the filter.

Great filter at a decent price. 5 stars from me.

Anyone who enjoys photography knows what an ND filter is used for. Since my focus is landscape photography, I can't avoid working with filters like this. I ordered this one from K&F for my full-frame camera. I was simply fed up with always filling my backpack with ND filters of varying strengths. That's when the Nano-X came in handy. I ordered it in 52 mm. I then work with step-up rings so that I can also use it on smaller lenses. To put it straight away: The optical quality and the quality of the images won me over! The workmanship is outstanding and very well done. The lens thread has a very clean cut. The filter is adjustable from ND 3 to ND 1000. The larger steps (f-stops) are marked on the ring and are easy to read. This way you know what you have set. The 52 mm filter weighs 28 g on my kitchen scale. Everything is solid and feels very good. The adjustment works well with slight resistance. That's how it should be. The optical quality is absolutely flawless, and even in difficult lighting conditions, the filter performs top-notch. Even when pixel-peeping, I couldn't detect any chromatic aberration or color gradients toward green, magenta, or anywhere else. Even with backlit foliage or fir trees and dew reflections, the filter's quality is unsurpassed. Finally, an ND filter that does justice to my limited lenses and full-frame sensor. The frame thickness with the thread is only 10 mm. Without the thread, it's 0.75 mm. This means I can also use the filter on wider-angle lenses without vignetting. Thanks to the screwed grip and the knurling on the ring, the filter can be adjusted very precisely. Conclusion: K&F Concept has delivered a top-notch filter. What's the point of investing thousands in lenses if bad filters make the work difficult or lead to poor results? A clear 5 stars from me. I hope this is helpful for your purchasing decision. The price is also put into perspective, as you save yourself at least four ND filters.