ordered this K&F Concept 43mm Ultra Slim Circular Polarizer Filter to use with my Fuji XF 35mm f2 lens. After lugging around a Fuji GFX100s and a set of GF prime lenses, I decided to try something different for a casual walkaround camera. I ultimately decided on a used XPro1 and a 35mm f2. My shoulders and back are so happy! The only problem is that all of my filters are designed for the much larger GF lenses. I usually stick with 77mm or 82mm filters and use step rings for lenses with smaller diameters, but I don't even have a step ring that fits the XF lens. With a 16MP crop sensor, files from the Xpro1 won't stand for the same level of editing that I typical apply to my GFX files. So, it's important to get the shot as close as possible to ideal instead of relying on "fix it in post." This K&F Concept CPL did not disappoint. It does not introduce any distortion, nor does is add a color cast. It rotates smoothly and does an excellent job at eliminating reflections without causing any vignetting. A few other reviewers have expressed difficulty removing the filter, but I did not run into that problem. I own other K&F Concept filters, and I would say that the overall quality of their products has been improving over time. If you do get a sticky filter, though, the slim nature of this CPL will make it difficult to remove. I do own a set of filter wrenches, so I tried using one on the CPL even though it was not stuck. I found that the wrench was able to grip the slim portion of the filter that screws into the lens with no issues.