After using a cheap polarizing filter, I wanted to try this product from K&F because I both really like the adjustable ND filter and the UV filter.
Unfortunately, I also have problems with autofocus with this polarizing filter. As a setup I use a Sony A7 M3 in combination with a Tamron 35-150mm f2.2-2.8. Although the lens does not have a built-in stabilizer, it delivers surprisingly good results with a steady hand. I won't be able to use the polarizing filter like this. I only get usable results with manual focus and I only have this time when taking landscape photos.

I needed a suitable polarizing filter for my Nikon 50mm lens. I am pleased to be able to test the K&F Concept polarizing filter from the K series in 52 mm.

I received the polar filter packaged in a plastic box and a microfiber cloth. It makes a very good impression in terms of workmanship.

Screwing it onto the Nikon 50mm lens went smoothly, you can feel when it is tight. But you shouldn't screw it on too tightly, otherwise it will be a little harder to turn.

The filter should then only be turned using the outer rubber ring, which is also very easy. Of course, if you touch the entire filter and turn it, you either turn it tighter or turn it off completely. That's what I did at first. But then it worked perfectly, just touch the outside of the rubber ring and turn it. Turning it on to an older Nikon 28-70mm was a bit tricky. After 2-3 times it worked.

The filter is intended for landscape photos to improve colors and contrast, among other things. I could notice slight differences, I hope this will become even more noticeable in midsummer.
I give 4 stars because the workmanship is very good, the handling is also very good and there is a very good price-performance ratio.

As far as the quality of the filter itself is concerned I have not noticed any problems, aberrations, scratches or distortion. The filter screws on noisily but none the less well and the adjustment lens is nice and tight which should prevent any creeping during use. Shooting downwards at the water, westward at late afternoon, gave me the opportunity to see how it handled glare and reflection. Although the pictures came out as boring as I expected, the reduction in both was marked and the effect variable with the rotation of the adjustment lens.

The only complaint I had was a niggling one regarding the quality of the packaging. I am used to first run (new) filters being packaged in protective film inside a hard case and then inside a cardboard box. That is true for other new 77mm filters I have purchased, including those from K&F. However, this filter came just loose in the case, without any protective film as cover. Luckily it seems to have done no damage to the filter.

All iin all this is a quality circular polarizing filter at a competitive price. It is well machined, fits perfectly and has a movement that is just tight enough to solve creepage. While I might have deducted 1/2 of a star due to the packaging, there is no mechanism to do that so my rating is a soft 5 stars; if you're in the market for a circular polarizing filter this one should definitely be on your list for consideration.

Hello,
For under 20 euros, the K&F Concept K-Series 77mm CPL filter is really not bad, but I don't think the term Slim in its item description is accurate, it seems rather robust.
It does a pretty good job of anti-reflective candles in the window, but increasing contrast in the sky could be a little better.
The box in which it is delivered is ok, but it slides around loosely in it, but the filter also has a 77mm thread on the outside onto which you could theoretically screw an ND filter or something similar.
If you don't want to spend a lot you can't go wrong, but compared to my slightly more expensive filters the image quality is a little worse but a good 4 stars for the price.

Today filters (like almost everything) cost too much in my opinion, in any case this is an affordable filter and it certainly won't be the best, but it must be said that it significantly improves the photos. I attach 2 very simple ones, one without the filter and the second with the filter. Bear in mind that it was taken on a "hazy" sunny day. In a few weeks I will have the opportunity to try it in different scenarios (which is why I purchased it) and I will update the review.

I continue to be amazed at the quality K&F puts out for a 1/3 the price of other brands. This CPL filter is the latest that I've added to my collection. Comes in the typical box with a cleaning cloth and it fit perfectly on the lens I purchased it for.

Threads in nicely and had zero binding. You just need to be cautious with over tightening this filter as with any other.

During several outings I was pleased with the results and I'm keeping this filter in the bag for 2 of my lenses. Well done K&F.

Fits well onto camera lens, feels sturdy and good quality. Good at reducing glare, particularly in bright environments. The camera lens cap still fits securely with it attached, although it does not screw on in its entirety. Additionally it comes with its own casing and cleaning wipe which is a nice touch to keep it protected when not in use.

Quick sample photo: with vs without. Detail on cloud is much clearer against the background and less washed out.

The K&F Concept Circular Polarizer is an interesting filter for your photos or videos. It can deepen the colors, especially the blues, or lighten them, and can be used to create interesting effects. I didn't notice any issues with clarity or negative effects from adding this filter on, and it actually enhanced my photos quite a bit, bring up the darker areas and making them more visible, adding or subtracting contrast depending on where you turn it. It's an almost excellent filter, but the threads could be a little smoother, as it felt a little rough when I was putting it onto the front of my lens. It was smooth to turn the filter once on the lens and easy to dial in whatever effect you are going for. fantastic filter for the price!

I like this filter for what it does. It removes a good amount of glare from bright lights. The bump in contrast and color is also noticeable (in a good way). I just wished I got the one that fits my 52mm lens instead of my 30mm. I do headshots and closeups with my 52mm lens and I might have to get another filter.

A very light and flat filter with the best workmanship.
No vignetting when used on wide angle lenses.
The camera's AF capabilities are not affected.