This filter has five stops. The stops are not locking stops, but there are indication markers for each stop. When you change stops, the filter moves very smoothly. The entire filter is quality in the materials and the construction. I like the feel of just moving it. It went onto my lens easily. I did not notice any vignetting from the filter on my photos. I also did not notice any cross effect and all photos seemed clear and without any color distortion. The filter does come with its own case, which in my opinion is a bonus. Five stars.

First and foremost, I have to say that I am pleased with my purchase of this particular Variable ND Lens Filter as someone (I'm a non-professional photographer) who has recently become interested in such kit/capability and don't wish to spend $100+ on higher-end equipment.

I see its greatest value in situations where time is of the essence and you are not able to fully control the situation - i.e., you don't have the luxury of time to set up shots using/switching fixed ND filters.

PROs:
*Doesn't appear to affect sharpness in any discernable way - The glass is of sufficient quality.
*Threading is tight and of good quality - Does not back-out when rotating the ND ring opposite to the way it is threaded on.
*Any color hue created in the lower ND settings is not too noticeable and is easily corrected in post. In several instances I've actually been pleased with the very slight hue it created and left it that way.
*The ND ring is tightly fitted but turns smoothly (no issues with it turning by itself when carried around all day - it seems to stay in place).
*Appreciate the plastic case it comes with to keep it from being damaged or collecting dust.
*Did not appear to affect my camera's autofocus and/or face detection.
*Probably obvious, but it's WAY faster to adjust this than removing and replacing fixed filters. This was handy when I was on a guided tour and in a vehicle where I didn't have time to change filters for particular shots, a common benefit probably to all variable filters of this type.

CONs:
*It does add a couple mm of length to your lens, but I suspect nearly all filters like this will do the same. If your camera/lens are already tightly fitted in your bag, having this filter on it could amplify the issue.
*No audible/tactile "click" when adjusting, although as stated before it's machined tight enough I never had any issues with it wandering from where I set it after several hours of walking around. More of a personal preference.

Summary:
For the money and its quality (at this price-point) it's sort of a no-brainer for someone like me who is/was interested in adding ND filter capability to outdoor photography, particularly landscape photography that can be troublesome during maximum lighting conditions (high noon) which can wash-out some contrast in your shots.

This is a review of a 77mm K&F Concept Nano-K Series ND2-32.

First impressions are that this is a very well-made filter for the price. The body is machined from aluminum, with a matte anodized finish. The threaded rear ring is nicely knurled. The rotating ring has very fine knurling on the front edge. There are varying sized dots on the edge indicating the number of stops (1-5) of exposure reduction. Numbers would be a little nicer, but the dots are not hard to figure out.

The rotating front element is larger in diameter than the rear. This should minimize any vignetting with wide-angle lenses. However, if you expect to stack filters on top of this, be aware that the thread diameters are different. On the 77mm version, the diameter of the front threads is 82mm.

The filter threads into the lens smoothly with no signs of binding as you often see with inexpensive aluminum framed filters. Once mounted, the front ring rotates smoothly, with hard-stops at 1 and 5 stop positions. The total rotation from the minimum to maximum position is a bit less than ¼ turn.

The 1 to 5 stop range is good for bright conditions where you need a slower shutter speed to sync with fill flash, or a wider aperture to better separate the subject from the background. If you need super long exposures for super silky water effects, K&F makes a variable 2-9 stop version, as well as 16 and 20 stop fixed ND filters.

The stop marks on the filter rim appear to be pretty accurate. Using aperture-priority mode, the shutter speeds were very close to the expected progression. Starting at the 5-stop setting, the speeds were 1/8, 1/20, 1/40, 1/80 and 1/160. And removing the filter yielded a speed of 1/320.

Coloration is the downfall of many ND filters. Through a DSLR viewfinder, this filter seems to add a subtle greenish-yellow cast. Surprisingly, in my test images this coloration is visible only at the lower density settings. By the 3 stop mark, the color balance is quite neutral. Overall, not a bad performance.

I shoot a lot of video and needed an 82mm ND filter, so decided to order this variable ND filter and I am glad I did. This is really nicely made, and is so easy to change levels of filtering, from lighter to darker by just turning it a little bit or a lot. It's a very visible change that you can easily see in the glass. The threads are perfect, and I had no problems screwing this onto the front of my lens or removing it. Image quality was excellent as well, with no visible distortion in my images whatsoever. This is a really nice filter.

The 43mm ND filter came in a typical filter case along with three pieces of microfiber cloth. I also own a 49mm ND filter from K&F which has been working well.

The filter looks well made. Clear markings on the filter and easy to rotate and set it to 1-5 stops for reduced light. It is easy to mount the filter onto the lens and remove it. One thing that was mentioned in the description but I missed to read it is that this 43mm filter needs a 46mm filter cap. I do not own a 46mm lens cap and so will have to buy one.

I have shot quite a few images with this filter, the light gathered by the lens is reduced as the filter ring is rotated to a higher stop. The filter ring does not rotate beyond the min or max stops and so this resolves the X cross problem. I will use this filter for long exposures when it gets a little warmer where I live.

This filter is not water repellent or scratch resistant and not slim. Filter quality is good, happy with the results so far. Price is ok at $29.99.

So, I have to say that this filter is a first for me and I am highly impressed. There are times when the sunlight can be quite harsh and I don’t want to go up or down stops. The filter performs well in bright sunny days. It’s made well and has a good sturdy feel and weight to it. I’m currently using on a 35mm 1.8 Sony lens. I cannot wait to put it through its paces this summer. Well worth its asking price.

✅ Made of matte anodized aluminum.
✅ The filter threads are well cut, easy to screw on.
✅ Avoid vignetting on wide-angle lenses.
✅ The adjustment range is convenient for various shooting situations.
✅ Does not cause image quality problems when shooting.
✅ It has resistance to chromatic distortion.
✅ Adjusts easily, with clear stops.
✅ Supplied with microfiber cloths.
✅ It works great with a wide variety of cameras and lenses.

✅ Made of matte anodized aluminum.
✅ The filter threads are well cut, easy to screw on.
✅ Avoid vignetting on wide-angle lenses.
✅ The adjustment range is convenient for various shooting situations.
✅ Does not cause image quality problems when shooting.
✅ It has resistance to chromatic distortion.
✅ Adjusts easily, with clear stops.
✅ Supplied with microfiber cloths.
✅ It works great with a wide variety of cameras and lenses.

Das Produkt wirkt jedoch hochwertig, der Rahmen ist aus hochwertigem Metall, vermutlich Magnesium, und entspricht sonst meinen Erwartungen. So ein ND-Graufilter wird benutzt, um die Lichtmenge, die in die Kamera fällt zu reduzieren, zum Beispiel für Langbelichtungsaufnahmen oder in sehr hellen Umgebungen, wenn man die Blende offen lassen möchte. Dieser Filter besitzt eine einstellbare Abdunklung, die man durch Drehen des Vorderteils des Filters regulieren kann.

Die Qualität ist gut und mit anderen Markenprodukten sowie Produkten der Marke K&F Concept vergleichbar, die ich mir schon vorher gekauft hatte.

Das Produkt kam sicher verpackt an, als Beigabe waren 3 Mikrofasertücher aus feinem, weichen Jerseymaterial enthalten, die ich nicht zwingend brauchen würde, aber die einen guten Eindruck machen.

Der Filter ließ sich ohne Probleme an meiner Nikon Z50 montieren, durch den dicken Ring am Filter ist jedoch der Blendschutz dann nicht mehr ohne weiteres nachträglich montierbar.

Die Bildqualität ist gut, es treten keine Farbverfälschungen auf

Da der variable Filter (wie alle Filter dieser Art) auf 2 Polfiltern basiert, die gegeneinander gedreht werden, tritt aber insbesondere bei geringen Abdunklungen aber ein Polfilter-Effekt im Foto auf.

Das ist aber nicht schlecht, und bei anderen variablen ND-Filtern ebenfalls der Fall. Häufig benutzt man ja sogar absichtlich Polfilter um Reflexionen zu minimieren, aber es sollte einem bewusst sein. Anders als bei regulären Polfiltern ist die Polfilter-Ebene hier nicht drehbar.

Beim Beispielfoto von einer Hecke sind die Effekte sichtbar. Das Bild ohne Filter (links) ist bei sonst identischen Kameraeinstellungen fast identisch zum Bild mit dem Filter voll abgedunkelt (rechts), außer dass ich die Belichtungszeit von 1/10s auf 30 Sekunden verlängert habe. Hiermit könnte man durch die lange Belichtungszeit gut verwischte Aufnahmen von bewegten Objekten (Wasser, Autos, etc.) machen. Mit dem ND-Filter auf niedrigster Stufe (mitte) sind die Reflexionen auf den Blättern durch den Polfilter deutlich reduziert, sie wirken viel grüner. Von den anderen Zwischen-Einstellungen des Filters habe ich kein Foto gemacht, aber es treten ebenfalls keine besonderen Farbabweichungen auf.

Nothing but high quality from K&F Concept. Their products deliver every time. This filter is no exception. ND2-32 is a daily driver, for the in-between shooting after blue hour and before golden hour. Adjust really easy and there are no X's in the images.