I have used K&F's products over the years and always been happy with the quality, attention to detail and thoughtful design. I own at least 40 filters of all sorts of types and brands and use them very frequently.

To be completely honest, I'm a little on the fence about this 3 in 1 filter as a concept. My initial thought when I saw this filter available was to pass on it because I was doubtful that combining a Black Mist with a VND+CPL didn't make sense to me from a practical standpoint. My main issue with it is that I spend $119.99 and i'm forced to always use the Black Mist with the VND+CPL. I think most professional photographers will likely think similar thoughts as I did.

Next, I thought how I would currently get the effect that this combination filter goes for. That means I put on an ND or VND, a CPL and then a Black Mist. Not to sound stupid but, that's three filters and using 3+ filters at once very frequently can add vignetting on the edges of the frame because the height of the 3 filters combined ends up blocking a little edge light. That's when I thought, AHHHHHH, now I see what K&F was thinking. This particular combination of filters is one that I use frequently, anytime I shoot a waterfall, river, ocean waves breaking on the beach or most varieties of light painting this is a great combination. CPL to help with glare and reflections on water, VND to slow down the light so I can shoot with a longer shutter speed and black mists are a favorite of mine to soften up that moving water so I get a nice smoke or fog effect.

In conclusion.. It's $119.99, for one good filter that isn't bad at all. I personally have several VND's, CPL's and Black Mist filters that are single function so I don't need more of them, but to have one that does all three which is ideal for a type of photography I very much enjoy.. Yea.. I'm good with it.

If you want a very good quality filter that handles a lot of the heavy lifting involved in getting that awesome waterfall or beach waves shot, then I can confidently point you to this filter as a very easy, high quality way to get the shot.

As an exclusive contributor to a prominent stock media agency with 25 years of experience in freelance photography and videography, I offer informed and professional opinions of camera and video equipment.

I will update this review if anything changes within 1 year. A 5-star rating indicates the product meets my expectations for its purpose.

The presentation of the Nano-X series is very nice. It comes in a nice case (fake leather I think) with a magnetic closure and a pull strap to eject the filter from the case. It feels well built and looks nice.

This appears to be the same as the cheaper K-series, with a nicer case and more coatings on the glass. I'm not skilled enough to notice a big difference between them as far as photograph quality, and don't particularly want to test the oleophobic qualities, haha! If this magically resists fingerprints than it is worth the cost difference. If not, then it isn't worth the difference to me.

Things to be aware of:
You will not want to leave this on your lens. You cannot mount additional filters on the front of it (only the back). Lens cap does not stay attached to the front because the front lip isn't really the same size, and of course this filter does not come with it's own. The knob for adjustments will prevent you from using a lens hood, of course.
The polarizer and variable ND work together. Because of this, you need to set ND where you want it first, then the polarizer. The knob for adjustment screws down to lock the ND in place for polarizer adjustment, which is a nice touch and something I didn't realize at first!

The K&F Concept filter fully surprises photographers: it is an exceptional device that will complement every photographer’s collection of accessories. It has granted me the ability to shoot using different colors of mist which was not possible before, to being able to control the exposure properly and many more. It is quite remarkable that ND, CPL and diffusion layers are combined in one filter which makes it very convenient and versatile. The build quality is good and the need for multi-coating technology for the bright color reproduction and minimizing the effects of glare and reflections is proved correct in this case. What I like most about it is that I do not have to use different filter options, in order to transform from one function to another. This filter does not disappoint anytime, whether used when taking landscapes or photos while holding the phone in portrait mode. For a beginner and even for a professional photographer It will be a perfect fit to their camera equipment, I wouldn’t have any hesitation to purchase one.

Fits my Canon 24-105L without any issues (although you won't be able to put on the hood with this on). Filter is well built, designed, and packaged. Comes with a leather case.
Filter itself also has a knob to help with dialing in the setting.
Does a great job in bright environments where you are at risk for washout from excessive lighting.
Overall, very happy with this filter from K&F.

From the moment you open the packaging, you know you've got a quality piece. I usually don't keep filter cases, but even the leather case is nice. I have a few other K&F filters, but this one just feels better. It's so nice to have a little adjustable knob to dial in the stops. Excellent piece of glass.

Quality products to buy with your eyes closed. An all-in-one that's easy to use. It features a polarizer and a variable ND filter that allows for all types of shots, from long exposures to HDR landscapes.
Used with a SONY RX100VII, it's the perfect combo for travel.
The only criticism would be the adjustment tab that sticks out, gets caught, and gets in the way in the storage case, but it's practical for adjusting exposure settings. So, there's a compromise to be made; it's up to you.

Camera lens filter, variable Natural Density, CPL and Black Mist. Helps balance sky-ground exposure, reduce reflections and soften images, ideal for landscape photography. Excellent quality guaranteed by optical glass with multiple coatings, anti-scratch, anti-dust and waterproof. Comes with a leather case for storage/transport and cleaning cloth. Be careful to choose the right diameter for your lens!

A very interesting filter, especially for its versatility. It takes up three of the space required by a standard filter. You can change whichever you prefer and adjust the light output using a lever on the side. Like all the filters I have from this brand, it's excellent value for money. I liked it. A good product.

A very practical 3-in-1 filter for photographers. The variable ND transition is smooth, the CPL reduces reflections well, and the Black-Mist effect softens the image for a more professional look. The optical quality is excellent, with no loss of sharpness. A must-have for any passionate photographer

PROS: this diffusion/nd filter is a nice addition for mt camera, excellent fr outdoor usage, fit my lens perfectly, it provides a nice smooth diffusion effect while filtering the sunlight well with the built in ND, and keeps the colours looking true to life. It also turns smoothly to adjust the ND. And i saw no X pattern at any stops.

CONS: its very expensive

Overall I would highly recommend this product to others