This is the flagship series from K&F, so if you want the absolute best filter they produce, this is it.

It has a brass ring, which is slightly harder than aluminum. That makes it more resilient to binding on the threads, and makes the filter itself feel much nicer in the hand.

It has inner and outer threading, so I can stack filters, or clip my lens cap directly to it. That's great for me as I don't have to ever take this filter off. The main point of this filter for me is protection, and it's so much nicer having a high end piece of glass to put on my high end lens rather than most UV filters that are a piece of plastic.

I tried to make it produce flares, and I couldn't get any. This is the closest thing to a perfect UV filter that I've ever used.

I also really like the design of the case. It has a pull string on the side that'll push the filter out so I don't have to worry about getting fingerprints on it.

Overall a very high end filter.

Highly recommended.

K&F UV filters come in a beautifully crafted cardboard box. It is also shrink-wrapped in plastic for protection.
As a little gimmick, you can use the insert and the cardboard that comes with it as a small picture frame if you wish.
The lens itself is stored in a scratch-proof storage bag. This itself is an eye-catching piece of genuine leather and is very well made.
A shrink-wrapped microfiber cloth is also included to clean and remove dust before installation.

The filter screws onto the lens without any problems and works easily and well without getting stuck or wobbling.

Ghosts are arguing over whether a DSLR camera needs a UV filter. In other words, I haven't noticed any negative effects on my photos so far.
Especially with the 82mm lens size, the price of around 150 euros quickly becomes predictable. It's better to have a scratched filter than a scratched lens, which will require an expensive replacement.

I ordered the K&F Concept Nano-X PRO Series UV filter for use with the Pentax HD DA★ 11-18mm F2.8 ED DC AW lens. As a general rule, I often use high-quality lenses without UV filters. Ultimately, quality decreases when glass is added to the light path. However, if you have dusty weather or rain, using a UV filter is definitely an idea as you can rub the filter with a cloth to dry it and remove dust. Even if the filter is scratched, the front element of the lens is still intact.

Next, let's talk about filters. K&F Concept Nano-X PRO Series UV Filters come in very fine packaging. The filter is inside the bag, and some are made of genuine leather. The clasp is magnetic. There is a ribbon on the side of the bag. Pull this and the filter will slide out of the bag.
A cleaning cloth and cardboard stand (?) are also included. Hmm, I don't understand what that means now. Perhaps it is intended as a presentation opportunity for dealers?
The filter is "made in China". The box has the address of the importer from Germany.

This filter can be easily attached to the Pentax HD DA★ 11-18mm F2.8 ED DC AW lens. I have nothing to complain about. The Pentax HD DA★ 11-18mm F2.8 ED DC AW lens will not be in the shadow of the filter. The quality of the filter is also very good.
I took some test photos with and without the filter and found no negative effects. Under normal conditions, I don't think the image quality will deteriorate that much. If the sun is at a right angle, you may experience light reflection issues in backlit images. But that would be a common problem with lens filters.

Conclusion:
The filter is really good. The 82mm filter currently costs 149 euros, which is not a bargain. After all, it doesn't make sense to buy a lens that costs around 1500 euros and then screw a cheap filter onto it and reduce the image quality. I give the filter 5 stars.

I've heard varying opinions on the benefits of keeping a UV filter on the end of a camera lens. Many people say it's smart because if you drop the camera, replacing a filter is much cheaper than repairing an expensive lens. I've heard others (particularly professionals) say it doesn't make sense to buy an expensive lens and then put a cheap piece of glass in front of it that will just degrade the image. Those folks say keeping the hood on the lens will provide plenty of protection and if you have an expensive lens, it should be insured against damage anyway.

I've invested in some good Canon L-series lenses so I'm torn on the best approach. I've been leaning towards going without the UV filter, but I still want one if I'm somewhere like the beach and sand or dirt is blowing. So if I'm going to put another piece of glass on the lens, I want to make sure it's high quality and this filter meets that requirement. You can tell when a vendor has put a lot of thought and care into a product and it shows throughout the process. This filter comes in very nice packaging and they provide a high quality case that has a magnetic latch and a nifty ribbon on the side that you pull to extract the filter from the case. This keeps you from having to reach in and possibly get fingerprints on the filter. Great design!

As to the quality of the filter itself, I don't see any aberrations in the image when I use it. This line of filters from K&F aren't cheap so they won't be for everyone, but if you are taking your photography seriously, you should consider this product.

As part of the Vine program, I received a free K&M UV filter to test. I was happy because I no longer had a UV filter that was perfect for the lenses I always wear.

The packaging is also very high quality and the bag it comes with is also very well thought out and easy to use. You can also make cute frames from the packaging.
A microfiber cloth for cleaning is also included.

Digital camera technology essentially doesn't require UV filters, as the sensor itself is already protected from UV radiation and the optics don't have to do as much work as they would with analog technology. A lens hood is all you need to protect your lens. Additionally, the lens does not have another layer of glass, which essentially reduces the quality to some extent. However, the lens is not protected from dust and sand grains. When taking portraits, I often lie down on the floor and get dusty, so I use it for portraits as well.
So far, I haven't noticed any negative effects on my photos.

This is a really high quality filter at a reasonable price.

K&F’s build quality has been second to none in the last several years. They’ve created a series of extremely high-quality filters using very slim precision machined brass rings ( brass is a much better material to use for this purpose than aluminum. It’s much less likely to strip threads or to cross thread) and excellent optical glass.

This filter is no exception. It has absolutely no optical distortion whatsoever. It filters UV and pretty much nothing else I think it has about a 99.9% visible light transmission.

Most people use UV filters to protect their lenses but it’s also helpful to filter out UV light for photographic reasons. It can help to increase the life of your camera sensor and prevent distortion in the images.

The anti-reflection coding on this is extraordinary. This competes well with my expensive high end German filters that cost up to four times as much money.

This filter is slim enough that it should not interfere with the image or create any vignetting even with wide-angle lenses.

This is my review for the UV filter but honestly every K&F filter I have purchased has been extraordinary.

Look at the photo and see if you can tell any difference.

I have many UV filters from multiple brands. This is now one of my favorites. Very clear, lightweight and well made. The included storage case also has a luxurious feel. Label the leather flap with a laser. It's strangely cool that the box becomes a picture frame.

The case has a very high-class feel to it.
However, since the filter is attached to the camera, I feel like it's excessive...

I think the filter itself is very good. I think it's a good filter because it's coated well and doesn't interfere with the image (both in terms of transparency and the thickness of the filter itself).

I don't know about long-term durability yet, so I'll update if there are any problems.

I'm glad I got my hands on one, but I haven't had a camera for a while now, so I wasn't sure what to make of this overpriced lens protection filter. So, I artificially created a ghost in my room and took a photo. Then...
I couldn't really tell during the shooting, but when I looked at the image file, the difference was obvious. Compared to the product made by M, this product also has ghosts, but there is a clear difference in the reduction in contrast around the ghosts. (I hope you can see the difference in the images shown in the review)
By the way, the product of M, a major filter company, is also a protective filter and costs 1,924 yen. (Purchased in 2018)
This product has about 10 times the magnification, but for example, if you are using a 300,000 yen F2.8 zoom, the extra 20,000 yen for the filter is well worth the improvement in image quality. (Sorry for the mess on my desk)

test data
Camera CANON EOS R6
Lens CANON EF 24-105 L
Shutter speed 1/6
Aperture F4.0
Focal length 24mm
Backlit light source LED stand
A tripod is used, and the focus, shooting angle, etc. are all the same for both shots.

K&F Concept's new line of pro-grade filters is truly amazing.

These filters are super slim and easily attach to your lens with a smooth thread.

UV filters generally do not produce color cast or optical aberrations.

A transparent filter to keep your lenses safe.

Comes with a padded case for safe storage.