I already own a Tiffen black pro mist 1/4 filter and as an addition I got the K&F set with 2 filters for a smaller lens.
The effect is significantly less than with the Tiffen filter, but I don't see that as a disadvantage at all. The light is slightly broken up and shines discreetly into the surroundings, but does not create such a strong halo effect. Personally, I really like the result and will use the filters often.
In my opinion the price is very fair for a set with 2 filters in different strengths.

I've used this when making movies primarily to add some atmosphere and/or soften the shot.

The metal feels good and solid and has some handles that grip well. I did the test with the camera pointed into the glare and the glare behind me. I like the effect, for me 1/8 and 1/4 are sufficient, plus you could stack them if you really want to increase the effect.

Two sealed microfiber cleaning cloths were included, a nice touch.

When you look into the light the effect is clear and you get a nice halo effect.

Overall, a great filter set at a reasonable price. Especially if you want something available but don't want to use it all the time.

Admittedly, I've never used a Black Diffusion filter before, so this was a bit of a learning experience. The filters themselves come well packaged in a nice plastic sleeve to protect them. They simply screw onto the end of your lens. The filters have nice handles that make it easy for you to put them on and take them off. The scope of delivery also includes some glasses cleaning cloths.

These filters fit easily onto my Canon EF lenses. I first tried a simple before and after portrait shot. The afterimage was slightly softened and some minor reflective glare was reduced to almost zero. In this case, I liked my after shot better than my before shot. However, it is important to note that the results achieved may vary depending on the lighting.

Next I created a shot with a light source in the background. The result was a bit surprising as I got a slight halo effect when using the filter.

In my opinion, the effects of this filter can be subtle or more pronounced, and that depends on how you set up your shot and where the light source is. I found these filters to be a pleasant surprise. There will be a bit of a learning curve for me in deciding when to use this.

This is a high quality filter set that allows you to add some interesting blur effects to your images.

I paid around €40 for both filters. Definitely something to have in your backpack! If the price is right, grab it!

The effects of the 1/4 are sometimes too intense for me, but if you have slightly darker scenarios where there aren't as many light peaks, it's great! The 1/8 is great!

I bought this filter when I want to have a softer look when shooting landscapes or long exposures and this filter works amazingly well.

K&F Concepts has always made fantastic products, I have many of their filters as well as a few of their tripods and their quality is top notch!

I have become a big fan of K&F filters. They are well made and easily screw onto my lens and other filters. I have one small complaint: I use smaller 58mm filters for my primes and this filter comes in a large box. Makes packing difficult.

The Black Diffusion filter provides a slight shimmer around the highlights and does not affect the darker areas. I did a test by using each filter individually and then together. The differences are very subtle. When you look at the water reflection, the filter gives the light reflection an impressionistic glow. Also note that the focus remains sharp on the bushes in the foreground. It also does a good job of adding a bit of Hollywood to the skin tones (not pictured). This is a far better alternative than adding a glow by post-processing the entire frame.

Seems like good value for money for quality filters.

I tested this kit with 1/4 and 1/8 versions of the K&F 67mm Black Diffusion (equivalent to Black Pro Mist).

Let's get straight to the numbers and results:

BLACK DIFFUSION 1/4
- average light loss from f2.8 to f2.08
- color temperature shift of 20 K (twenty Kelvin) to the cooler side of the Kelvin scale (warmer color)

BLACK DIFFUSION 1/8
- average Light loss from f2.8 to f2.09
- color temperature shift of 20K (twenty Kelvin) towards the cooler side of the Kelvin scale (warmer color).

CONCLUSION:
This filter set behaves satisfactorily with the expected light loss at these diffusion levels and shows only a very small, not to say insignificant, color shift.

The form factor is very light and thin, ideal for use in gimbal and compact camera setups.

This pair of diffusion filters is the perfect set for someone who is just starting out or looking to add some options to their camera bag. Diffusion filters are very subjective and, similar to seasoning according to a recipe, depend on the individual's tastes and preferences. That's why I really like the fact that there is not just one diffusion filter, but a second one with a different performance. This actually gives you three options as the filters are also stacked and combined, albeit with much greater softness in the image.

I tried these in three configurations and have included some example images and videos to show others how this can affect the image in different situations. I found these effects to be very enjoyable, even when stacked at the extreme end. And as a big bonus, there is almost no noticeable color cast with these filters, which is not usually the case with more “budget” level filters. These filters far exceed their price, especially considering you're buying two of them.

These did a good job particularly when the images contain obvious light sources, such as in the night example. The lights are enveloped in a wonderful glow that gives the image a certain something and softens the harshness in a pleasant way without removing the details in the image.

I really enjoyed using these filters and can't wait to continue trying them out in different situations to see how they work. I recommend keeping them in your camera bag and trying them out on all your shoots just to see what can happen.

Since these filters only fit properly into their housing when stacked, be careful not to overtighten them. This also applies to mounting on the camera, otherwise they will get stuck. However, this applies to every filter brand and is not specific to this one. I only mention it because they have to be combined to fit into the case. Of course, you can always use a different case if you don't like this aspect.

By the way: K&F has always impressed me with its products. I own several now and have not been disappointed with any of them. And at the usual prices, it's worth adding to your collection even if you don't use it all the time, to try something new or to inspire some creativity when you're a little bored.

The “Softer” function softens the image without changing the color too much. This makes editing easier when working with a LUT

I really like the filters from K&F Concept and the Black Diffusion 1/4 & 1/8 Filters Kit Mist Cinematic Effect Filters Set is no different. I like that the two different filters can be combined to create a greater effect. The fog effect/black diffusion is subtle. When photographing a person, it can help blur the skin and this would be perfect for portraits. I found the easiest way to see the effect was to take a photo of the sun. In the image with the filters you can see that the sun appears larger and has a nice nebula around it. My lens' filters do have a slight vignette when I'm not zoomed in, but otherwise it's a decent filter that I'll definitely use.