Bought this for my Sony 200-600 and the lens cap does not fit on the filter.

I find the optical quality very good, pixel peeping on a Sony a7IV and Sigma 150-600C images remained sharp.But the adjustment rotation is VERY stiff, even with the nice big knurls it is difficult to adjust.

I have been looking for a 95mm CPL filter for a Sigma 150-600mm Comp. lens that does work and does no lose picture quality at full zoom and the K&F CPL 95mm filter does the job 100%!!!

My first experience with the K&F Concept filters was with the purchase of a light pollution filter I've been happy with, particularly liking the grippy knurl added to the edges of the filter. After accidentally scratching my Hoya NXT Pls CPL 82mm filter which is more than double the cost of the K&F filter, I decided to purchase the K&F Nano Series CPL filter and see how I like it. Moreover, I also chose to go ahead and buy a 95mm version as well, to replace a Pro Optics (Adorama house brand) filter that I thought might be a lesser quality filter. Both K&F filters arrived today and a visual inspection of them reflects a quality product as I expected. However, one minor complaint is that I like the round K&F filter case which as a rigid plastic insert that appears to be grooved to support holding any of various sizes of filters securely in place in the case....that is, perhaps for a range of filter sizes, K&F may be using the same case to save manufacturing costs. However, while the 82mm filter arrived with that same case, the 95mm filter was in a more common, square plastic case with foam cutout to hold the filter. Still fully functional, just not as nice as the case provided for the 82mm filter. I don't expect to see any problems with the cheaper case, but it is the type that frequent use could find the plastic hinge wearing out eventually; I simply favor the 2-piece round case of the smaller filter.

Ths CPL turned out to be great. I was afraid that the green nano-coating could cast a greenish tint on the image. I haven't noticed any annoying green tinting although it does have a slightly warmer and maybe yellowish look. Nothing that can't be controlled with proper white balancing and some minor editing. I find this CPL to be really good for the money.My only issue: my lens cap seems to not fit properly over this filter. I can still use it but it falls off easily. Keep this in mind.EDIT: I'm taking a star from this because taking the filter off is a nightmare. I use a high end UV filter from B+W on my favorite lens and got this K&F cpl for that same lens. Before purchasing i asked and made sure the filter was not only stackable but good to be used over any filter, including my specific UV filter reference, and i was told, here on amazon and other sites, that it was totally fine. well, I'd love to have some of those advisors to try and take off my cpl from that B+W filter. It's like they fused together. Moreover... I had an accident yesterdayand the cpl got some mild scratches. I'm trying to take it off so i can decide whether to get a new cpl or not. Well, no matter what i try (and I've even tried the rubber band trick K&F has on youtube), its not workingLong term review: after a few days i managed to take the filter off. The scratches were minor so i kept it. I've been using it quite often ever since and now I'm super careful not to tighten it too much. Learned my lesson the last time. I still like it, but it lacks some power, specially when taking pictures of stuff in the water. It works, in the sense that with patience and a very good angle, you can see stuff under the surface, but it still leaves sone glare and reflections. When i use it on other super shiny surfaces, however, it's quite good. I know this isn't an expensive filter so i still recommend it for the money, but if you are serious about it, you'd better save some extra money and get a higher quality filter. I don't earn in dollars, so to me it's a fair steep difference between this tier of cpl (which i consider affordable and acceptable) and the next level. But i really want a better one and will eventually replace my K&F filter

I'm using this filter on my telephoto lens (200-600) and it works great.

Used to help reduce some glare from snow and it helped a lot. Fit great threaded on snug and smooth. Perfect fit.

Recently bought the K&F 18 layer super slim CPL polarising filter to replace my broken Hoya (which had to be cut off a lens as the thread jammed!). I have to say I'm very impressed with the build quality and also the performance. Considering how cheap it was compared to my previous one I didn't expect it to be great, but I can see no difference between it and my old (much more expensive) Hoya! Definitely recommended