I've recently started getting a visit from a woodpecker in my garden and have always wanted to take a photo but the reflections from the window always ruin the shot. I tried this polarizing filter today and it's amazing how much of the reflection it filters out. The images are much clearer with no haze and I think this works well for quick pictures through the window. Now I just have to wait for him to come back and hopefully actually get a photo of him. The filter seems to be good quality and is fully coated and uses Japanese glass. With the filter on there is no loss of image quality or sharpness. It also improves the contrast of the sky and I can't wait to get out and properly test some landscape shots with it. Overall I'm very happy with the filter and for the price I think it's good value for money.

This is the first lens filter I have ever used. I've always read/heard that a good filter can make a significant difference, but until now I've never gotten one. This polarizing filter is very nice! The high-quality construction of glass and metal is easy to see. In my pictures you can see that the filter is attached to my camera, but I was able to attach my lens hood directly to the front of the filter. It has front pickup threads in addition to the rear threads. A really nice feature is that the front of this filter rotates freely. This way I can now easily rotate the tulip hood to the best position without the risk of the filter or hood loosening. I couldn't do that when the hood was connected directly to the camera. But does the filter make a difference? I am happy to say that it works very well! I often take pictures through a window and it's very common for the picture to have some "haze" that wasn't there when I took the same picture outside. I took a picture through the window with this filter and was pleasantly surprised to see a picture that looked like I took it outside. I don't know exactly how this works, but it does. Just like polarized sunglasses, this filter "steers" the light in a way that enhances what you see. I am impressed! I often take pictures through a window and it's very common for the picture to have some "haze" that wasn't there when I took the same picture outside. I took a picture through the window with this filter and was pleasantly surprised to see a picture that looked like I took it outside. I don't know exactly how this works, but it does. Just like polarized sunglasses, this filter "steers" the light in a way that enhances what you see. I am impressed! I often take pictures through a window and it's very common for the picture to have some "haze" that wasn't there when I took the same picture outside. I took a picture through the window with this filter and was pleasantly surprised to see a picture that looked like I took it outside. I don't know exactly how this works, but it does. Just like polarized sunglasses, this filter "steers" the light in a way that enhances what you see. I am impressed! I don't know exactly how this works, but it does. Just like polarized sunglasses, this filter "steers" the light in a way that improves what you see. I am impressed! I don't know exactly how this works, but it does. Just like polarized sunglasses, this filter "steers" the light in a way that improves what you see. I am impressed!

The K&F D-Series UV Filter is a well-made, durable optical device that appears to perform as advertised. I wish I had noticed that the NANO series filters are a little better and only a little more expensive. In any case, if you compare this D series filter directly to the B&W UV Protection Filter (010) (XS-PRO), MRC Nano, the K&F product seems to be of the same quality and performance for less than half the price .

I've broken down my review for you and them into reason for purchase, first impression, product test, suggestions for improvement, tips and conclusion. I hope this helps with clarity.

I received the product free of charge as a Vine product tester, but this has no effect on my review. I also only test things that I can usefully use myself and integrate into my everyday life.

Reason for purchase:
I ordered this filter for 2 reasons. The first reason is that if I only want to travel with light luggage, I don't want to bring my entire plug-in filter system with me. The second is that I can use it well in videography, where I usually film according to the 180 degree rule. This means that in order to obtain a cinematic video image with a certain amount of motion blur in the individual frame, you film with a shutter speed of 1/fps x 2, for example, I film at 50fps, so I need an exposure time of 1/100s, which is not possible without an ND filter, especially in the wide angle range when the sun is shining.

First impression:
The packaging looks very classy, but she is also welcome to do that, given the price that is called for the filter. The filter is in an equally pretty and high-quality filter bag, which I have never seen in this form with round filters before. With the tab on the side, you can lift the filter to prevent accidental contact with the glass when removed. The closure of the bag is magnetic. A nice gimmick is that the cardboard packaging of the filter can be transformed into a small picture frame.

Product test:
The filter is a dream to the touch, heavy (91g) and easy to grip, I also really like the contrasting adjustment aids. These can also be removed if you want to continue using a lens hood. This requires a small microtorx, e.g. from a precision engineering kit. When the filter is adjusted, it is buttery smooth across all stages.

In the test, the filter shows no weaknesses. As a result, I could not detect any color cast and there was no X-Cross effect. The promised effect of up to 5 aperture levels is maintained. Technically perfect and that is the most important aspect of an ND filter.

Suggestions for improvement:
1. The sustainability aspect, as taken up when using cardboard as a picture frame, could also be reflected in the filter bag by avoiding the use of animal products (leather).
2. An 82mm variant would be desirable and recommended, then the filter could also be used on (m) a 24-70mm/2.8, for example.

Tips:
It is always advisable to buy such a filter in the largest possible diameter so that you can adapt it to as many lenses as possible in your own fleet using step-down rings. Of course, this also eliminates the option of continuing to use a sun visor.

Conclusion:
Technically perfect filter in the upmarket price segment.

I hope my review was helpful in your decision making

UV filters are much more useful for film because UV radiation affects film much more. However, this is still useful for protection, both from UV rays if you shoot a lot, and from dust and other particles. In most cases there is almost no visible difference between the on and off lens. So if you want a little more protection for your lens, this is perfect for you.

Ok but doesn't show back window.

This filter offers the protection I needed at a reasonable price. I've been using it for a few weeks and it fits securely and is well made. It comes in a hard plastic box with a small piece of foam. Would recommend to anyone looking for a UV filter.

I simply copied the complete text from my YouTube video for you. Who wants to see the video
"Variable Nano X Slim ND Filter I pure waste of money when buying?" Enter on YouTube...It's ND Filter that's hard to beat for value for money. It's about a filter from the company K&F Concept, this manufacturer's name is actually familiar to everyone who is - a bit - at home in the photo and film segment. And K&F Concept also stands for quality.
It's about the filter called NANO X Slim Filter. It is offered from a 37mm thread and goes up to a 86mm thread. Thus, it covers almost all offered lenses. He weighs just --- 45gr.
He has a total of 5 f-stops, it starts at ND2, 4, 8, 16 and ND32.
The filter comes with a nice round packaging as a transport box, so that it can also be safely stowed in a backpack or bag. But what is most important, especially for those who always leave the filter on the lens ---like me--- is the fact that glass is the filter's scratch resistant.
Screwing it on and off is wonderfully easy. If you buy it, you should definitely note that you can then usually no longer use your lens hood. Because the thread size on the front lens changes. Attention, however, when buying sun visors - it is essential to pay attention to the zoom range in which the lens is and accordingly buy a sun visor. Of course, I also had to buy a new sun visor, which I bought first was from 24mm, not intended for wide angle. My lens was 17mm – 28mm though. When I was completely in the zoon out, on 17mm, I had nice black edges in the picture. --- Stupid beginner mistake stop. So be sure to pay attention to the zoom area covered by the sun visor before you buy, just as a little tip.
The ND filter can be set very easily to the different ND levels and the individual levels are very well marked, so that you always know exactly which level you are at. Changing the ND levels is so easy because the filter is slightly corrugated all around and has a small pleasant resistance when turning.
In some recessions I've seen that some say the filters would appear to produce X-patterns at high f-stops. What I can't confirm with my film work at first. There is a spin stop, and no overlap, when setting ND16 to ND32, so the X doesn't actually show up. I only have the filter for filming, I'm a videographer, not a photographer, and I think it does a great job. A photographer and a full professional filmmaker will probably not use a variable ND filter anyway. I film a lot at f1.4, f2.0 and 2.8 and shutter 1/50 and even there, although everything is very open glare, the filter comes through perfectly, and very well with. Unfortunately, and that would actually be the only thing you could complain about, is that the filter has no IR cut. In plain language, --- IR, --- means infrared blocking filter. This blocking filter blocks wavelengths in the infrared range. What this filter does not have. But at the price?? somehow also understandable.
What does an ND filter actually do? ...
If some should ask themselves that.
Quickly and roughly explained ---- little basic knowledge.
First and foremost, an ND filter reduces the incidence of light and so you can still film in very bright situations, for example. Without totally overexposing the recordings. So also a longer eg. shutter speed possible. Who doesn't know the great pictures of streams or waterfalls, where the water looks like a veil, like in a dream world. You get that with a good ND filter and exposure time, for example, and not, as some people think or suspect, with good Photoshop skills.
I work a lot on the water, on the beach, on the sea, and that's how I always get the water nice and smooth.