This review is for the 2-in-1 True Color ND variable and CPL polarizing filter from K&F Concept's X series (Nano-X). The advantage of combining dual functions of ND and CPL is the ability to quickly adjust both amount of light and polarization, usually a challenging situation faced outdoors near lakes, pools, or reflecting glass surfaces like high rise windows. The variable ND has 5 stops (ND 32, 16, 8, 4, 2) and rotates infinitely. K&F promises no "X" cross on images. The construction is AGC optical glass with 28 multi-layer plus titanium coating to reduce glare but produce true color with no yellowing. The 77mm circular filter is lightweight and machined extremely well with an interesting orange tab on each side of the circle for fast adjustments. You grab either tab that is convenient, they both adjust the ND stops. I was able to easily twist this onto the front of a step-up ring that I have on my Sony alpha 5100. It's an older camera but the pictures have always been great when using the right combinations of lens and filter. I can confirm that this truly delivers the easiest experience for quickly getting a high quality image by adjusting for light and polarization in one filter. With the proper assortment of step-up rings, your investment in this filter can pay off by using it on multiple devices you may own. To protect your investment, it comes in a nice faux leather case. This is an outstanding ND + CPL combo for quality images in many outdoor situations and the sliding tab makes adjustment so easy.

The ideal of combining these two commonly used filters into one is genius. I really like all of their filters, but the convenience of this is fantastic. Works great on my 24-70. I don't see any color shift or image degradation. Adjustments operate very smoothly. This one is always in my bag now when I go out to do landscape photography.

own many K&F filters. Every single one of them is well made and fit my lens like a glove. They are all made of quality materials. The optics on this lens are premium and worth every penny. Another great filter to add to my collection. If you don't have a ND/CPL, I highly recommend trying this one out. It does not disappoint.

Another home run from this company as they make great filters. Screws on nicely and pictures are vibrant.

Using the filter is a breeze. The variable ND aspect ranges from ND2 to ND32, giving you a wide range of light control options. It's like having multiple ND filters in one. Adjusting the density is as simple as twisting the filter, and the markings are clear and easy to read. The integrated CPL function is just as user-friendly. By rotating the outer ring, you can adjust the polarization effect, which I've found incredibly handy for reducing glare or enhancing the sky in my landscape shots.

Bought this for my iPhone. It's the perfect fit for most phone cases with a lens adapter. It's also the perfect size for most mirrorless camera lenses as well. Color shift is minimal as you shift to stronger ND levels. Though, it is present and can be corrected in post. The build quality is solid with physical stops at the lowest and highest settings. This prevents accidentally going into cross pattern territory. Detail and sharpness reduces slightly at highest ND setting.

This is a great combo filter. It comes with a very nice leather-like pouch and feels sturdy and nice. I got the 67mm and it fit perfectly on my Canon RF 85mm f2.0 prime lens -- look on the rear of the lens cap for your lens' diameter. The lens cap fits on top of the filter just fine. I also have an RF 35mm f1.8 with a 52mm diameter -- I ordered the K&F Concept 52mm to 67mm Step-Up Lens Filter Adapter Ring so that I can easily switch this expensive filter back and forth rather than having to buy two filters. One thing to beware of is that it seems like it would be very easy to over tighten this and get it stuck. It doesn't screw on and stop -- you can keep turning it. I nearly went too far the first time I put it on so now I don't tighten it as far as I would like. The filter itself works wonderfully. I like the combined ND and CPL filters. The ND is for removing some light when taking videos (since you can't really adjust shutter speed for videos) and the CPL is for removing light reflections for videos or photos. It makes it look like when you put on a fancy pair of polarized sunglasses on a bright day. I do wish the variable turning handle had some hard stops or even any kind of tactile click when it gets to the next stop, but it is smooth and so you have to have it away from your face and look to see when the dots match up visually rather than being able to click through the settings with the camera up to your face the whole time. Overall though, this is a terrific filter with high quality engineering from a trusted brand. Would highly recommend this.

This is a very well made and packaged K&F filter that offers both a circular polarizer and variable neutral density functionality in a single 77mm package. Build and thread quality is top notch. K&F packages their filters so nicely and includes a solid carrying case. Recommended.

have a number of K&F filters, and I've not been disappointed in any of them. I think K&F uses high quality glass for their filters, and this is preferrable to plastic or cheaper glass. (Yes, in some instances you really can tell the difference.) This is a combination neutral density and circular polarizing filter. The former cuts down on light entering through the camera lens (nice on really sunny days and a must for longer exposures when photographing things like waterfalls and moving water). The latter cuts down on reflections, allowing you to get better shots when shooting through water (such as rivers and ponds) and glass. K&F's promo sheets states their lenses are scratch resistant; I can't vouch for that as I really baby all my lenses and filters and I'm not going to intentionally test this. If you can swing the cost of the K&F Nano-X filters, go for them. They'll last a long time and add minimal to no distortion in your pictures.

As a full time filmmaker I own several K&F filters. They are cheap but have a solid performance. Especially fir your output medium is Social Media or even TV. (I would not use them for Film related projects). One of the problems this ND filter solves is especially when you using a Matte box and you have the ND attached to it. It is really hard to "feel" the filter without looking at it. I have smudged the lens with my sticky fingers several times because I can't really feel the ring while holding the camera. This filter has to nice handles that you can tactically feel easily when using a matte box. Great addition for my camera bag.