This polarizing filter and neutral density filter pleasantly surprised me, it is not overpriced and the quality of the photos is not bad at all, I have taken several photos with the different degrees that it allows to subtract light and the result is good, if you like silk effects in the water this is an essential filter.
It also has the polarizer that eliminates reflections on crystalline surfaces.

52mm ND2-ND32 (1-5 Stop) Variable ND Filter and CPL Circular Polarizing Filter 2 in 1 for Camera Lens. What can I say about it? Exceptional. Having the ability to simultaneously adjust the ND filter and polarization without swapping out filters is super convenient. Quick adjustments can make a big difference in whether you get that perfect shot or video pan in the moment. I have a Sony ZV-1 with a 52mm adapter for lens and it seamlessly and smoothly threads on without issue. Although my camera come with a build in ND filter. The K&F takes it even further by along more control of how much light my camera takes in. The polarization aspect of the K&F further expanses on the quality of the picture. Overall, I’m extremely happy with this product.

Bought this for my 35mm f2 which I am using on a Canon RP. I wanted it for slowing down the shutter speed for waterfalls I'll visit this summer, as well as deepening the blue in skies. It works as advertised. Nice metal build quality that feels well made. I like the stiffness on the variable ND part. It stays where I set it, and so far it's working great at reducing the light coming into the camera, allowing me to use longer shutter speeds to get the flowing water effect I was after. I usually use the polarizing part of the filter on the lowest ND setting. I'm adding two photos that I think show the polarizing effect pretty clearly. There is some colour difference between using the filter vs not as well as at different filter settings (rotations). I think this is pretty standard, at least I've observed it in the polarizing filters I've used in the past. I've been satisfied dealing with colour shifting using WB and calibration adjustments on raw files in Lightroom. I don't see any degradation in sharpness. I'm pretty picky and do view files at 100%. Very glad I purchased this filter combo. Great value for the money! I'll also add that I accidentally used it once over a thin UV filter and was glad to not see any vignetting.

Easy to attach and detach. Whilst it only provides a minor polarising effect the variable ND filter is easy to adjust, although the CPL/ND combo adjustment takes a little getting use to.

For the price this is fantastic. I'm only a student so the like of polar pro and such are out of reach and was always stuck with cheap brands (including older K&F's) that ruined image quality with x marks and colour cast.
But then I discovered this and I have to say I'm impressed. No colour casting or 'X' patterns and my footage looks crisp as if there was no filter at all. And the fact that it's a CPL aswell is a huge plus.

Would recommend.

To make it short - this combo filter is very good value for money, as long as you're getting it for the right reasons. While not quite up there with "pro-level" filters in terms of quality, it does a great job for what it is.

Firstly, the main appeal of this filter is combining CPL and variable ND functions onto one - which saves you from having to stack multiple filters (which may end up not working well together) and makes for one less piece of glass between your lens and your target. I've noticed no flaws whatsoever in how the two functions work together - no Xs, no artifacts. The CPL part of the filter is very, very good. The variable ND part is... fine. Better than a lot of filters in this price range. There is still a slight brownish cast from it, but it's totally consistent and very easy to correct in post-processing. Just don't expect stellar results right out of the camera, without a couple of clicks' worth of extra work!

In terms of filter factor, it's more or less spot on - it's a little bit more than 1 stop of light at the lowest setting (ND2), but at the highest setting it seems to be pretty much exactly 5 stops of light - not the 5 and a half you'd get if you took an ND32 filter and put a CPL over it.

However, the real question is: do you need this filter? Because the max setting of ND32 is generally a bit too light for landscape photography off a tripod (you'll want an ND64 or even ND1000 filter there). For longer telephoto lenses (over 200mm focal length), you really don't need this kind of filter for the obvious reason that you're not likely to be getting too much light. For wide-angle lenses, the CPL portion makes it a complete no-go - on anything shorter than 35mm focal length, it'll completely mess up your image with those uneven shadows (not the filter's fault - but CPL is really not designed for that).

So, what is this for, exactly?
Well, I can't speak for video usage - but in stills photography there's one area where this filter really excels, and that is for handheld shooting in bright daylight conditions with large, wide-aperture lenses at the higher end of portrait and lower end of telephoto: in other words, lenses between 80mm and 200mm focal length and f/2.8 or less when wide open. This allows you to really control and thin out your depth of field and shoot at shutter speed that will minimize noise, while being able to control more of the stray light from reflections thanks to the CPL.

I use it for creative photography with just two such lenses, both totally manual: the Samyang 135mm f/2, and the Helios 40-2 (85mm f/1.5). It is very handy with both, really hits a sweet spot for usability despite how bulky those lenses themselves are, and really brings out the kind of extreme subject isolation and bokeh both of them are capable of. So, if you own monster prime lenses of that kind (between 80 and 200mm, f/2.8 or less) - this is a great filter you really will find useful. But beyond those? Might be worth checking something else!

Otherwise, my only other criticisms are about ergonomics: the filter uses some kind of non-standard thread on the outside, and has too little thread left anyway to screw anything over it - so if you were thinking of putting a hood or any other sort of attachment over it, you'll have to forget it. And on too of that, the little "handles" for controlling the ND variation stick out just a bit too far from the body of the filter... so you can't really attach a lens hood behind it either, save for a flexible rubber one - and even then, the "handles" will likely deform it a bit. Long story short - expect this filter to always end up on the very end of your optical train, and expect to have trouble even fitting a lens cap over it without it constantly falling off. It's not a big deal as far as I'm concerned - but you may find yourself putting this filter on and taking it off to store it in a box every time you go out to shoot. Not ideal if you want to put it on a lens and forget about it.

All in all though, I'm very happy with it! Worthy buy and a handy tool to use.

We bought this 2-in-1 filter for a shoot that was shot outdoors. We encountered no problems filming at the water's edge with the glare of the sun. For the price it's excellent, the variable ND2 to ND32 filter is really sufficient for video. It is possible thanks to the filter to keep cinema look parameters on the camera, with a large aperture, a low iso and a nice bokeh. The filter is of good quality to the touch, we realize that it will not break after several screwing and unscrewing. The advantage of this filter also lies in the 2 small peaks, which make it possible to properly adjust the ND part of the filter. In short, if you want to buy a filter for your camera, we recommend it given its price. Really great!

One of the only few filters that do not have the 'x' in the photos due to 2 filters combined, and it is the best for the price. I have several sizes for several lenses that live on the cameras. The packaging is always presentable and the filter itself is of good quality. little to no effect on photos.
Recommend 10/10

Excellent buy for my camera. I must recommend this. Easy to assemble, easy in use and great enhancement to your photography. With this, I got excellent landscape picture with balanced brightness and clear details of sky & clouds. ND filter adds advantage over waterfall pictures. love it !

We bought this 2-in-1 filter for a shoot that was shot outdoors. We encountered no problems filming at the water's edge with the glare of the sun. For the price it's excellent, the variable ND2 to ND32 filter is really sufficient for video. It is possible thanks to the filter to keep cinema look parameters on the camera, with a large aperture, a low iso and a nice bokeh. The filter is of good quality to the touch, we realize that it will not break after several screwing and unscrewing. The advantage of this filter also lies in the 2 small peaks, which make it possible to properly adjust the ND part of the filter. In short, if you want to buy a filter for your camera, we recommend it given its price. Really great!