Let me preface this review by explaining how I use these filters. I’m a wedding photographer and my wife is often my second photographer. I shoot Sony and she shoots Fuji. We also shoot wildlife and landscapes. Between the two of us I have purchased 23 K&F lens filters. Since we are working photographers, and rely heavily on our equipment, this UV filters are pretty important. I have had 3 lens front elements saved by UV filters, and because of that they have been worth it. These have been situations where a lens was dropped during a switch and landed on its UV filter, a cat pulled down a camera strap and the camera and lens landed right on its UV filter and another incident where I was taking a group photo in a church and my slung camera hit a corner of a chair’s back rest. These are all situations where the UV filter saved the lens. In all situations I was able to unthread the filter, pick up the glass shards and keep shooting. The first two situations the lens hood actually broke too, and in the chair corner situation, the corner was at a perfect angle to fit right in and get the lens filter.

There have also been situations where I’m shooting in the rain, or near a fountain and I can just wipe water off the front lens element with a microfiber cloth without needing to take them time and very carefully clean it.

Regarding this specific UV filter, it lives on a Fuji 35mm f2, and is thin enough to match the small lens body. It’s super low reflectivity means that it’s very hard to put it in situations where it has any effect on the image. Basically, it’s there for protection and has a near zero effect on image quality. Nothing more to ask for!

I’m including photos of portraits of my Kitten where she is directly backlit and another where the sun is just next to her. These were both shot a the Fuji 35mm’s maximum aperture of f2. In the photos where the sun is just to the side of the subject you can see purple blobs that are not present in photos without the filter. It was actually very challenging to get these purple blobs! I had to shoot a ton of photos into the sun, and the purple blobs were only present in very narrow angles. I’m not seeing any haze or loss of contrast and the only downside to this filter is those very hard to create purple blobs.

I got this to protect my Sigma 150-600mm lens, and the 95mm filter fits it perfectly. The filter has some heft to it and appears to be made very well, with very good materials. I only took a few photos with it, but I didn't notice any real difference in my photos with the filter on, but I know it will do a good job protecting my lens.

For a portrait and night street project, I wanted less “digital hardness” in the pictures — that's why I ordered the Black Mist 1/4 in 72 mm.
After two weeks of use, the first thing you notice is the workmanship: brass frame, grippy milling, the thread runs smoothly and the filter sits flat on the lens. The flat profile is also nice; the original lens cap fits further on.
The 1/4 effect is clearly visible: highlights get a subtle glow, skin becomes a bit softer, contrasts look more pleasant. In bright daylight, it can be a bit “dreamy” — for architecture or very detail-critical motifs, I prefer 1/8.
Positive: hardly any reflections or color stitches, the nano coating is really easy to remove fingerprints, and the case is practical when out and about.
All in all, the filter quickly delivers the cinematic look that I would otherwise build longer in the mail. Not a bargain in terms of price, but the effect and workmanship justify it for me.

Perfect filter. Essential to protecting the front glass on your lens. This filter does not affect the natural flaring of the lens and it's very low profile and lightweight! This is a must have for any photographer! Great filter quality like the rest of my k&f filters. 10/10 recommend

Very good quality Black Diffusion 1/4 Filter from K&F Concept made from very good materials.

I have been using this filter for just over two months and so far I have had no issues it works and works extremely well you get that soft and creamy look to your images of course you need good lighting to get the effect. This filter will help take your images to the next level.

The filter is thin and lightweight which is great BUT due to it being so thin there has been a few times when I have struggled to get a good grip to unscrew the filter from my lens I have always gotten it off so this is not a game changer for me personally. With the filter on it is still 77mm so your lens cap/cover can still fit so you can leave it on if you want to when not using the camera.

Comes in a very nice stylish material case good stitching which gives this a professional look and feel, has magnet in the case which is used to close the lid/case these are all very nice touches.

Overall I am happy with the Black Diffusion Filter I feel it is a fair price and I would recommend it.

I generally find all products from K&F Concept to be of great value and this Black Mist 1/4 filter is no exception.
I got the 77 mm version and paired with my trusty Nikkor Z 24-120 F/4.
The manufacturing quality is at such a high quality that you don't have to think twice when ordering: brass socket, strong thread, no wobbling whatsoever. Unscrewing and unscrewing is as smooth as butter, every single time.
As for the filter itself, its effects are immediately noticeable: it reduces the sharpness from digital cameras, reduces skin blemishes and gives highlights that subtle, cinematic glow. Except for edge situations, when the lights are overly bright or coming from certain angles, there are no image degradations when using this filter. No reflections between the filter and the lens' front element.
In broad daylight, the effects of this filter might be a bit too strong. The image can become a bit too dreamy. Then the less strong model, the 1/8 might be a better choice.

What can I say, K&F gives birth to this 1/4 Nano Xcel Pro black mist and it's crazy. A must-have filter because it gives a “vintage” paste to the photos by cutting the black areas and giving that slight glow that, especially with the lights, has a more cinematic appearance. Top quality and amazing results. Both on video and on photos the results are so good that I decided to leave it on the camera by default. K&F is always a guarantee and if taken in combination with the 1/8 one the pleasure increases dramatically. Especially on video you will see that muffled and smoky situation that is usually obtained by using the smoke machine to isolate the subject from the seabed.
Absolutely recommended.

K&F Concept filters are great, made from really good quality materials with clear optics.
They're not the cheapest, but the old "you get what you pay for" saying fits here.
You get a really handy plastic case for it too which makes travelling with more than one filter much easier.
Fits on my Sigma 24-70mm lens no problem and you can still use the lens cap and hood as you would normally.
UV filters are a great way to protect your lens and reduce reflection, increasing detail.

Great filter

Tested during a night walk in the city. The street lights get a soft halo that makes the scene more atmospheric. Sharpness stays where it's important.

In everything I'm going to say below, there are sample images.

I'll start by saying that the package it comes in is very well presented and complete.
It comes with the typical vacuum-sealed microfiber cloth and the solid case that holds the ring, plus you can store other filter sizes in it.

Regarding the filter, I zoomed in and looked at the sharpest areas, confirming that the loss of quality is minimal or nonexistent, meaning it's a very good option for keeping the lens protected.

Although it surprised me, since you might expect a UV filter to lose some brightness (even if it's very small), the opposite happened. As you can see in the histogram of the photos I've posted, the brightness increases slightly, even giving me zebra in some areas of the curtain. A curious phenomenon.

Interestingly, when it arrived, it was so clean that the glass was barely visible; it looked like an adapter ring. I also didn't notice any color drift or any kind of tint. You can see in a backlit photo of my hand holding the filter that it doesn't change.

I've had several products from this brand, and they're reliable, just like this one. I would definitely buy it again.