I had researched the qualities and capabilities of an ND filter. What I did not like was that each 'level' of ND effect were a separate lens and to buy a range of them would cost money and add bulk to your camera bag. When I found this variable ND filter, at a reasonable price, I ordered it. I like that, with one lens, I can change the density quickly by a simple rotation of the lens. Where as, if I had a set of ND filters, I would have to guess what effect I wanted, select a lens from the set, screw it on and hopefully not miss my shot. True, for a tripod set up and all the time in the world, you could try different lenses and compose your shot but most of my work is wildlife and at-the-moment shot. A great addition to my camera bag.

I posted a previous review on two other sizes. I would definitely recommend this.
Note that in the description and on many of the negative reviews there is a reference to distortion/'x' shape in the photos when this filter is dialed up to maximum. Now that you know, you can easily avoid this. Don't dial it up to maximum, where that artifact is visible.
I'm using this for a variety of photos - landscape, portraits, etc. Have also used this same brand for video on another lens and got great results.

Well, the ND filter simply does its job. It gives me a lot more control over the 16mm f/1.4 lens from Sigma, which is an excellent piece of glass. Since it is a fast, wide angle lens, there can be challenges which are easily dealt with using an ND filter. I did read the comment from a reviewer that mentioned an dark "x mark" across his image. I had to see if I could replicate it with this. I cranked the filter way past what I would have normally set it for, and was able to see the x as well. Neat. It's easily fixed though. Just don't "crank" an ND filter further than is necessary. I have a feeling that most all of them will exhibit the same characteristic, so it's just a matter of operator procedure to see that it doesn't happen. Honestly, I had never noticed it, simply because it was a setting that was never called for, given any of the lighting conditions I was shooting in. I can go to manual settings on my camera, and get a blacked out image, if I push the settings into "deep space", but why would I? Otherwise, the filter shows good edge sharpness, and no detectable distortion, but I'm not terribly picky. It gets rid of what problems I might have had with a high speed, wide angle lens, which is what I bought it for. Nice ND filter, and I'd buy it again.

Fit the lens well and seems well built.

Very nice, works very well, save having to have several ND filters