18 coatings on the lens...well that's a lot of coating and this is just the lower budget K series range to K&F's X and X-pro series which have 24 coating layers. I am reviewing the 67mm Nano K-series here, but I also own the Nano X series of this same ND2-400 filter at 77mm which is about twice the price.

So whats the difference? Well having only so far tested this K series filter on a waterfall video scene on my monitor, the only difference is in packaging and presentation. Performance-wise, this filter seems to perform as good as the X series one.

As shown in my photos, The filter shows no flare, chromatic aberations, or cross effects. Once I have taken it out for more real world sunny scenes, I will know for sure and update my review.

So, in other worlds, this feel as high quality as the more expensive equivalent variable X-series filter.

However, when going to approximately 7 stops and over, the colours seemed washed out. Under 7 stops, the colours really pop. At all stops, the picture is sharp in the focus areas.

At this point, this feels like terrific value for quality results.

Just one grip, I have. There are no intermediate markins for the ND values or stops. Just notches. And there are no clicks, it's all continuous. I would have liked some click stops. But its a very minor grip at this price.

One more thing, as shown in my photo, this works and threads smoothy on my K&F step-down rings.

Ordered the 37mm diameter filter. Comes in an opaque storage box plus you get 3 microfiber cleaning cloths. Nice tactile response in adjusting the fader. Beautifully made and perfect fit on my Panasonic camera lens.

This comes well packaged and in its own sturdy plastic storage case, I am pairing it up with my Sigma 16mm lens.
The filter has plenty of scope for stepping the light down ND 2-400 and produces a nice image.
The rotation is smooth and accurate , I will mostly be using it on brighter days and for images were I require the light coming in stepped down but with plenty of scope.

I have and reviewed a few Neutral density filters. They are one of my favorite tools to use in landscape photography. This will be my first Variable ND experience. I'm familiar with K&F so it was a no brainer to give it try. I'm looking to improve my odds of getting dramatic skies on days that are very overcast or hazy. My camera has Aperture, ISO and shutter speed that unfortunately don't impact the hazy and overcast cloud cover situations. This filter will be a 4th way to control the light, and that by dimming select portions of the light simply by rotating the dial. When set up, we will be essentially changing the light coming from the cloud part of the frame but leaving the rest of the light details unchanged. Thats the high level view of what this does. It functions by turning an element on the front of the lens that will let you see which areas are being affected.

In Use like other K&F products, they include a sturdy case to keep the optics fingerprint and smudge free. This particular kit includes 3 free microfiber cleaning cloths, individually wrapped. The few days I went out with this it was cloudy but not hazy or overcast. Still, the filter brought out more detail in the clouds and made them a tad less exposed Improving the overall shot. I will continue to use these confident that under the overcast skies I'm going to bring out more cloud sharpness and definition and cut through the haze. So Far so good.

First off, I would like to say that I have purchased several filters and devices from K&F in the past and have always been happy with their products. This variable ND filter was another well-made filter with which I was pleased. With some other brands, I have had trouble with adjusting the filter to make changes to the density of light that was allowed through. This one I found to adjust very easy, but not so much that you might bump it out of position. This 52mm filter is for use on my Canon cameras and has once again expanded the options I have available. This shows that a quality filter can be purchased for a reasonable price.

K&F has risen to the top when it comes to choosing filters for my cameras. They produce products at various price points while delivering excellent value and performance. This filter is no exception. Minimal color shift with no other visible artifacts (X). Smooth rotation through the stop range (no clicks). Given the cost of this filter, this is an excellent value.

This variable density filter is ease to use and keeps decent color balance. Essential lens for your kit. Recommeded.

Firstly the quality of this ND filter is outstanding and a real joy to have in my camera bag and fits my Canon DSLR's perfectly, I did a few test shots on fast moving clouds and they turned out perfect and actually saturated the cloud colour to a deeper blue with brilliant blurred movement in the surrounding white clouds and i can't wait to try it out on waterfalls and seascapes,

Made with top quality optical glass and once fitted to the lens you have full control using the turn ring with each F stop clearly marked on the outer ring and the results should be amazing with Sea and Rivers etc i am itching to get out and give it a proper test but so far with the test cloud shots i have been blown away and can clearly see differences in each stop down i used during the test and everything was crystal clear and sharp, The filter comes in a neat plastic protective box and they throw in 3 microfibre cloths too which is a real bonus, I have a few filters from this company and every one is a winner as they produce high quality filters i would highly recommend and would certainly buy again.

33 at time of review

I'm using it on a Sony A7C and a Sony FE 20 1.8 G lens so if there's any issues that combination would reveal them.

I took a series of test shots without the ND, with the ND fully open, and with it stopped down too maximum, both with auto and manual white balance. I shot away from, towards and perpendicular to the sun to check for flaring and glare. With the filter I didn't notice any additional flare than without. Colour rendition was good too, I didn't see any sizeable shift in colour (yes there was slight bit, but you will always get that no matter the manufacturer, it's physics!).

I shoot a lot of video, so use variable ND's for that, although I always use variable ND's from the same manufacturer on multi camera shoots as there is always a slight colour shift (usually more noticeable when stoped down), and having now used this I'm happy to say it worked very well. I've several Tiffen ND's and they cost at least twice what this costs and frankly I don't see any issues at all with these (in fact one of my Tiffen's has awful colour shift that I can only use it with stills not video).

Hope my review was helpful