I really wish they added hard stops to these things. I don't understand how this isn't a feature on all filters and not just those that cost $200+
30/12/2021
Lots of vignetting even at lowest setting. As you get halfway through the darkening you start getting blotches. At full darkening there is a dark visible X in the picture. I am very curious how this filter go so many positive reviews. I find it unusable. I am returning it and will look for something more expensive that works or simply go for fixed ND filters
25/09/2021
Great ND filter BUT will not work with lens cap. Once I put it on my Sigma 24-70, the lens cap that came with it would not work. The filter itself is larger and will have to grab one of those rubber caps. Sort of annoying but great results!
18/09/2021
The K&F Concept 77mm Ultra Slim ND2-ND400 Fader appears well made especially given its modest price. The threads fit well when placed on the lens, and the filter does not rattle. Rotating the filter allows an image to become darker with the goal of using wider apertures in bright sunlight.
30/12/2020
I was surprised to find that while this ND works decently for wide angles lenses, It cannot achieve a sharp image with longer lenses. During my tests I discovered that the focal plane becomes distorted on longer lenses such as 85mm, 100mm etc which makes it impossible to obtain a sharp focus. . your image will be soft when using this ND on 85mm and beyond which isn't a problem with other Variable NDs like Tiffen, Neewer and just about every other Variable ND on the market.
20/10/2020