good

Looking forward to put this filter to the test! Looks and feels premium. Will order again!

It's a good Product if youre on budget. Whats negative that it has X pattern 2 steps before nd 400 and from 35 mm it creates vignetting and theres no hard stop. But as i mentioned before if you are on budget its fine.

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.

Ich nutze den Filter für die Landschaftsfotografie bei der Langzeitbelichtung von Wasseroberflächen.

Pro:
- Sehr gute Einstellbarkeit der Abdunkelung
- Filter präzise gearbeitet und lässt sich leicht drehen
- Kleiner Hebel macht das Einstellen leichter - allerdings bleibt er auch gerne an der Kammertasche hängen beim entnehmen oder zurückstecken der Kamera
- Keine optischen Fehler feststellbar (Flares, Schärfeverlust...)

Contra:
- Baut einigermaßen lang und daher erhalte ich bei 24mm Brennweite bereits eine sichtbare Randabschattung

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.

I bought this for my iPhone, and never found an adapter with decent enough ratings to buy yet. However, while holding it in place as I take pictures of record some video footage, it is actually surprisingly good. I'm not sure if the same experience would translate to a Camera, but overall seems like a pretty good product.