Right from the start, the first thing you will notice is the build quality of this filter. It feels very solid in your hand, there are no loose parts, and it has a good weight. I like that it has small handle extensions that you can hold onto to turn the filter. Since the filter takes some pressure to turn it, it's nice to have these so your fingers don't slip. I like that the ND filter has hard stops so you don't accidentally turn it too far, which can mess up your image very quickly, regardless of which brand filter you use.As for color shifting

As for color shift, it's about par for the course for this price range. It's neither the most natural nor the worst when it comes to color shift that I've ever used. If you turn the ND filter on more, it tends to lean toward warmer tones, but that's easy to fix after the fact. I have yet to come across a filter that had no color shift at all Look at my image for a side by side of the same scene, shot with the ND filter and without.

Overall, for the price, I would definitely recommend it. K&F did a really good job with the materials used and also in producing a good quality image.

I was very reluctant to buy an ND filter for a while until I took the plunge with this one, and it's been a turning point in my image and video capture. The quality is superior and it makes my work much easier.

Anyone who likes to take pictures knows what you use an ND filter for. Since my focus is landscape photography I can't help but work with such filters. I ordered this one from K&F for my full frame camera.

I was tired of filling my backpack with ND filters of different strengths. The Nano-X was just what I needed. I ordered it in the size 52 mm. I then work with step up rings to be able to use it on smaller lenses.

To say it right away: The optical quality and the quality of the images has convinced me! The workmanship is excellent and very successful. The lens thread is top clean cut.
The filter is adjustable from ND 3 to ND 1000. The larger steps (f stops) are marked on the ring and easy to read. So you know what you have set.

The 52 mm. Filter brings 28 gr. on my kitchen scales. Everything is solid and feels very good. The setting runs well with slight resistance. This is how it should be.

The optical quality is absolutely flawless and even in difficult lighting conditions the filter delivers top. Chromatic aberration or color gradients into the green, magenta or anywhere else I have not been able to determine even when pixel peeping. Even with foliage or fir trees in backlight and with reflections from dew, the quality of the filter is unsurpassed. Finally a ND filter that does justice to my limited lenses and the full-frame sensor. The frame thickness with thread is only 10 mm. Without thread 0.75 mm. So I can use the filter on wider angle lenses without edge shading.

Thanks to the screwed handle and the ribbing of the ring, the filter can be adjusted very sensitively.

Conclusion:
K&F Concept has delivered a top filter. What's the use of spending thousands on lenses, but then bad filters make work difficult or lead to lousy results? From me clear 5 stars. I hope this is useful for your purchase decision. Also the price is relative since you save at least 4 ND filters.

Packaging and shipping

The ND filter arrived super packaged, the ND filter is delivered in a fancy box that looks really classy.
In the box is a small leather bag in which is the variable ND filter.
Really excellent, here the filter always has top protection.

Quality and function

For the quality of K&F you do not have to say much, which is excellent.
I now already have tripod from the manufacturer and a graduated filter set and am always thrilled.
About the function, I made a small video that you can see how the filter changes when turning.
I find the idea excellent with the small lever so can easily make the filter lighter or darker.
My other filters I had name I do not want to call here, has turned at some point the whole filter with and lay in the dirt and the glass was cracked.
This is now a thing of the past, high praise for this great invention since the photographing is much more fun.

My conclusion, from me there are 5/5 stars
Thank you that I was allowed to test this great product.

Works as it should. No cross bars. Love it!

Love this filter! Worth every penny if you’re truly into photography. Helped my 70-200mm so much on bright days.

This definitely worked well for sunny settings so I was able to take long exposure/low shutter speed photos without worrying about them being too bright or a completely white photo. The materials are high quality and I like the packaging it came in. Definitely recommend especially if you’re a beginner photographer like me.

High-quality filter would purchase again

bought a 77mm D Series VND filter for my 70-200mm F2.8 lens back in March 2024. I'm not a professional photographer, so I don't use my camera very often and usually avoid shooting in high-exposure environments. I finally used the filter for the first time at a car show in June 2024 under bright sunlight and noticed some focusing issues. After some research, I found out this is a common problem with the specific lens I use. Since the return window had already passed, I decided to reach out to KF Concept directly. I explained my situation to them, and they were super understanding. They allowed me to return the filter with a restocking fee and even offered me a discount on a recommended replacement filter. I thought that was really nice of them, especially since it was my fault for not testing the filter when I first got it. The Nano-X Series VND filter they suggested works perfectly, and I couldn’t be happier with it. KF Concept’s customer service was fantastic, and they made sure I felt supported throughout the whole process. I’ll definitely keep buying their products. It’s really reassuring to know that their customer service has your back and is just as excited about their products as you are.

Working great on my Sony 18-135mm lens. No issues whatsoever.