I'd wager that if you're looking at these filters for your x100 camera it's probably because you, like me, enjoy the film sims and want the softer feel to the photos (you know you've seen the videos talking about these like I have), and look there are a TON of options out there. Cinebloom, black mist, white mist, haze, whatever. The list goes on.

At this point, I now have a 1/8 black mist, a glimmer glass and now the 1/4 black mist and here are my thoughts:

The 1/8 version is very, very subtle to the point that it's barely noticeable unless you're looking for it or you've got a specific situation. The glimmer is the same for me as the black mist in terms of subtlety (same strength). The 1/4 strength black mist (this K&F one) is the one that tends to be on my camera the most of the three, though.

The build quality is excellent, and it doesn't interfere with the focusing of the lens - IF you have a lens adapter. PLEASE NOTE that you will 100% need an adapter with these if you're putting them on the x100 line of cameras or you risk damaging your lens. If you've got the adapter, though, then no issue - it allows the lens to move fine and it focuses quickly.

The 1/4 mist provides just enough character for my personal taste without making every single light bloom too exaggerated or every crisp line look like it was smudged with vaseline. It softens the sharpness just enough to take the digital character down a notch for those times when you want to fully enjoy the film simulations, and if you've never actually used a mist filter for things like light blooms and softening light sources then you'll be happy to know that this one does it well.

These filters aren't something that I use all of the time, but for the times when I am after what they can provide they come in very handy, especially because it allows you (on your fuji cameras) to turn off the clarity setting and speed up your workflow when firing off shot after shot without delaying the processing power of the camera.

I've used K&F filters alongside my more professional, "premium" filters for years and have never had an issue with them and this one is yet another one that does great in that regard. Whether you want the 1/8, the 1/4 (this) or even the 1/2 or more I think you'll find this filter to be worth the affordable price.