TL;DR - Impressive performance. Honestly, I'm shocked.

I work as a professional photographer. I have a terrible gear addiction. I pixel peep.

These test photos were shot on a GFX100II with the 23mm F4.

I typically use B+W filters (Clear Basics 007), but I needed an 82mm filter and was inclined to try out this K&F filter. I don't consider myself a gear snob, but I certainly did not expect this filter to perform as well as it did.

In my experience, most clear/uv filters are quite good nowadays and will not degrade your image quality. Reasonably priced brands like Urth/Gobe, Neewer, Tiffen, and Hoya all perform really well and I would argue at parity with brands like PolarPro or B+W when it comes to basic image quality.

Higher end filters tend to show their value when it comes to controlling ghosting, flare and hazing. In my experience every filter exacerbates flare and ghosting, no matter the manufacturer, but the higher end brands tend to do it better.

My testing methodology hardly qualifies as rigorously scientific, but I did my best to force my lens to flare. To my surprise, the image with the K&F filter is surprisingly well controlled. I expected much worse, but it is quite good all things considered.

There is definitely a bit more vignette with the filter as can be seen in the second set of photos, but nothing too serious.

Image detail (No flashlight), is indistinguishable between filter and no filter.

Just a few comments on build quality. I do appreciate how thin this K&F filter is, but the machining and material used in the construction of the filter is definitely several steps below B+W or PolarPro, which makes perfect sense; for the price, there had to be compromises. But I think it's a worthwhile trade off given how great the glass itself performs.

One other thing I will mention is my own personal experience dealing with K&F. I highly recommend purchasing directly on Amazon and not on their website, especially if you aren't 100% certain of your purchase. Despite their no hassle return policy, I had a terrible experience attempting to do a return on a product. I'll just say it was a drawn out affair that involved days of e-mail tag and finally a store credit despite there being a clear discrepancy in their product description.

Customer service aside, they do make some quality products, so don't let that deter you from purchasing from them.

I will continue updating this review as I have more time to use the filter out in the field.

For now, I shall tentatively award this filter 5/5 for giving me such a great first impression.