K&F CONCEPT 39MM Polarising Filter Circular Polarizing CPL, Ultra Slim, Japan Optics, Multi Coated, with Cleaning Cloth (Nano-K Series)

Great addition to my kit for car photography

Update: K&F have been in touch and sent me the X Series filter that does work fine at all focal lengths. Much better customer service than I originally received. I’ve changed the rating to 4 stars, as this filter did work really well while not at full zoom, and may not cause any issues at all to smaller lenses. It’s well priced and fits and works well. I just wish there was an acknowledgment of the known issue at higher focal lengths in the description to better inform customers. Original review: Very disappointed. The filter does work well, as long as you don’t use your lens at full zoom. Obviously while you’re out you definitely want the ability to shoot at full zoom, 200mm for me, but you can’t as the photos are completely blurry. I did contact K&F for assistance, their reply was that the issue is because I bought the K-Series. And if I now spent more money and bought the X-Series it “will likely eliminate the focusing problem you’re encountering.” As a gesture of good will they have offered a 20% discount, but I don’t feel that’s good enough. There was nothing on the product description to say there is a known issue with this filter, and I don’t think I should be out of pocket any more than I already am. Because of this I couldn’t recommend this filter. Two quick, unedited photos attached showing without and then with the filter at full zoom. Photo is unusable!

Edit: I have upgraded from 1 star to 5 stars to reflect on the outstanding customer service I received. I had a problem with the filter I received but the company got in touch with me and offered me a refund, replacement, or an alternative filter (which they despatched almost immediately). The filter they sent me works beautifully. Things go wrong sometimes and I was very impressed with how well and how quickly they responded to this. I would have no hesitation in purchasing from the again Fits easily and turns easily, Works ok for wider shots, but on full zoom the image is unusable. I took two shots with a Nikon Z6 and the 28-400mm lens, shot on manual at 400m, F/8, 1/320s, ISO 100 The first one is with no filter and the second with the K&F filter. It's cheap so not worth returning but I will need to buy something that works at 400mm

Really nice filter I got some awesome pics with it

New to buying lenses but this seemed to do the job I was looking for! Great quality and price!

Due to the anti-vignette design, it is very thin despite having a freely rotating ring for the filter element. If there’s any sort of recess it is incredibly difficult to get it screwed on tight enough, that rotating the filter won’t also unscrew it. Virtually incompatible with clamp-on matte boxes. Works OK on regular lenses without accessories.

This was bought for my Panasonic DC-FZ82D camera. It fits nicely and works well insofar as it reduces reflections. However, it also significantly reduces the transmission of light through the lens. This is a problem when trying to photograph pictures and items in galleries and museums which are behind reflective glass; there is little enough light in those situations. It's a long time since I last used a polarising filter and I don't recall the loss of light being so great in the past. Maybe a more expensive filter would allow more light through while still effectively blocking reflections?

Maybe I’m doing something wrong but my camera won’t focus when the lens is extended with the filter on. It is not a camera or lens issue as they work perfectly without it. Any suggestions are welcome. Otherwise a waste of money! Edit: I have received a refund for the product. Thank you!