Transparency notice:
The product was made available to me free of charge as an evaluation sample, free of any influence or expectations. My review is based solely on my personal assessment and experience of using the product.

Review:
For quick readers, I'll preface my review, below I'll explain the details of my decision making, my impressions of the product.

I only make a minimal deduction of points and award 5 stars, i.e. 5 stars rounded up.

My only criticism is that the filter rotates slightly too slowly, i.e. its operation when it is screwed onto the lens, but I hope that will subside a bit over time. No, the turn isn't slow, but it's a bit tough, I expect a slightly smoother movement here.

Workmanship:
The slim frame is of very good quality, precisely processed and painted. I like slim filters, they build up less high on the lens and therefore do not limit its viewing angle, especially with a strong wide angle.

Slim filters can have the disadvantage of being more difficult to handle, as the grip ring is very thin. It is helpful here if it is handy and that is exactly what the K&F filter is.

I can grasp the filter very well and see no problem even with wet fingers.

The glass in the filter is of very high quality, optical glass, very precisely processed and absolutely flat, and has also been coated several times.

First, pick up the filter and look through it, preferably against strong contrasts and straight lines, such as a façade.

Here you can see that you don't see any glitches. I don't notice any distortion, the image is absolutely flat, over the entire surface of the filter, and I don't see any color distortions, I'm very satisfied.

It looks no different when I screw the filter onto my lens, but here is another aspect, possible reflections, but that is exactly what a polarization filter is supposed to eliminate.

In terms of image effect, this is absolutely undisputed, whether on a water surface or on windows, reflections are suppressed very well, as expected. But there is another aspect and that is the reflections on and behind the filter towards the lens when backlight comes in at an acute angle due to small punctual light sources. I don't see any reflections here, which speaks for the very good coating and glass quality of the filter.

I am very pleasantly surprised by the packaging of the filter and that starts with the attractive outer packaging in a high-quality slipcase.

It contains a flip case with magnetic closure, it is very decorative and practical, much higher quality and more elegant than the commonly used plastic boxes.

Conclusion: The K&F polarizing filter is not
a bargain at just under €150, but it is inexpensive in the sense of the word and is clearly placed in the premium segment. The processing quality itself is just as impeccable as the optical imaging performance on the lens. The included case is very attractive.

Only the somewhat slow adjustment of the orientation minimally disturbs the overall impression, so I subtract half a star for this. In the overall impression, this only plays a subordinate role and leads me to an almost unrestricted purchase recommendation.

Thank you so much for your attention when reading my review. If you'd like, feel free to give me some feedback, I'd be happy to hear from you.