First K&F filter and actually surprised a bit by it's quality for such a affordable price

Product: 58mm Variable ND2-ND32

Description: The rim of the filter is made out of what I'd assume is aluminum, coated matte black, (which has a nice weight to it, and has hard stops at ND2 & ND32). The rim itself is actually fairly nice. It's easy to put on, and easy to take off due to the wide ridged design around the base of the filter. The high index optical glass is indeed nano coated to protect against water/oils from fingerprints, rain, & etc. Which are easily removed without struggle in my testing with a clean micro fiber cloth (not included). The glass itself has a slight yellow tint to it (which you can see from the photo comparison), which can also easily be corrected through your cameras auto white balance, or lightroom. The filter also doesn't loose to much detail if adjusted properly which is nice as you will see from the photos, and their description in the next section.

Photos: The first four photos of the product were taken without any filters. Though the next two of the black & red mouse pad were to show detail comparisons. These two photos were taken about 1-2ft away, but are cropped to show detail. Which were slighty adjusted to be as equal as possible.
Without the filter: F4.0 1/15s. ISO 400
ND32: F4.0 1s ISO 400

The next 6 photos of the flowers next to the bird bath were taken without adjusting any settings to show the darkness of the filter (F5.6 1/320s ISO 100), in this order: No Filter, ND2 1st, 2nd, 3rd, 4th, & ND32 5th stop.

Overall: The produce works well, and is well made! I would highly recommend picking one of these up, along with a circular polarizer. Though only notable things I found with the product is that it has a slight yellow tint of the filter, the front thread size of the filter in bigger then 58mm, and the top of the filter very slightly wiggles. Otherwise it gets a solid A from me!

Extra: I used a 49mm-58mm step up ring for the filter to fit my Canon 50mm F/1.8

Camera/Settings: Shot on a Canon Rebel SL3, with custom white balance settings set to +/-0,+/-0 for raw color quality.

Filter is not wide enough to accommodate even a standard zoom. I have it mounted on a Sony 18-105 f/4 G lens paired with my Sony a6300. In photo mode, all four corners have a very HEAVY vignette. The vignette is visible from 18mm all the way until about 50mm. 18mm isn't even considered wide - angle on an APS-C Camera. The build quality and image quality itself are very good, however, the vignetting renders the filter unusable. Avoid this product if you plan on using it with a lens wider than 50mm.Update: K&F Concepts offered to send a fixed ND 1000 filter plus Step down filters so I am able to use an ND to take photos. I appreciate the help that they offered me so I updated the rating of this product. This 72mm Variable ND filter is very sharp and has no color fringing. If the vignetting issued gets resolved then it would be a near perfect product - especially for the price. Good customer service but subpar product.

I have a Sony A7III with a couple of the Tamron lenses they recently release, 67mm thread on both. I used the ND for the first time on a shoot in broad daylight mid-day and loved the results. Best part is being able to dial in very easily the amount of stops I need to make the zebras go away. Smooth operation and sturdy construction. The only negative is that the lens hoods no longer fit once the ND is on. Not a deal-breaker but be aware.

EDIT: Also took it along for a trip to Lake Tahoe and it came in very handy for those longer exposures and to get more contrast out of the sky. Awesome and so easy to use!

Typically you get what you pay for when it comes to camera gear but this product is one of those rare exceptions. I was very hesitant to purchase it based on the price but after watching dozens of reviews on variable ND filters I figured I would give it a shot. I have never been a fan of variable ND due to some of the image artifacts they are known for. I always used individual ND filters as needed which can be a pain when shooting run&gun video.

I loved that this ND filter had hard stops to not go past the usable points of filtering and that they somehow eliminated the dreaded x shape in the picture. While photos may be able to recover from some of these artifacts it is much harder to get around them in video.

So far I am completely blown away at how good this VND filter has performed. The picture quality as far as my initial testing has shown is stellar. Color cast seems to be at a minimum and there is absolutely no X shape or vignetting. To be fair I bought the 82mm size version and use step up rings on my GH4 and m43 lenses but so far even on the 62mm wide 14-140 lens visually the VND seems perfect.

My only super tiny issue which is true of all VND filters is that turning a filter on the front of the lens while shooting video is very easy to accidentally get my fingers in the shot. Would be nice to have the option to screw in a tiny handle into the VND so I have something to grab onto and not get my fingers in the shot. Maybe something the manufacturer can consider for a future product.

This is a good quality variable ND filter. While the marketing says that there is no "X", this is not true with wide-angle lenses (due to physics and such), as I noticed an "X" on (or near) the lowest and highest most settings. Other than those extremes, the filter works great on my wide-angle lens. On a typical non-wide-angle lens you do not have the "X" showing up.

I especially appreciate that they had a 55mm size, as it is an odd size. My Canon mirrorless 11mm - 22 mm lens has the 55mm thread, so this filter is perfect for my needs. I can also use this on my 49mm threaded lens with step-up rings.

I purchased the K&F Concept 52mm Fader ND Filter Neutral Density Variable Filter ND2 to ND32 for my Sony RX100 vii because the camera has no built in ND filters for video.
While I had purchased a 3rd party ND filter adapter ring and separate 52mm ND filters, I found the numerous additional filters were just too much to carry with such a slim and low profile camera.
The variable ND reduces the need to carry 4 additional filters, and I only had to affix the K&F Concept 52mm Fader ND Filter Neutral Density Variable Filter ND2 to ND32 to the adapter ring. Now I only carry 1 ND filter for when I need it, and it does all I need.
With regard to picture/video quality, this filter works great, and I have not had any distortions, rings or Xs when using the variable settings.
It works great!
The Filter comes in a nice box, and within the box is a great plastic case for storage in a camera bag.

I enjoy this filter! I have it on a 24-105 lens that I have pretty much started using exclusively except for a couple of other lenses here and there. I used to shoot all the time with a Sony FS5, and its ND filters were pretty much on this level. The first screenshot is color graded somewhat, and the other screenshot is not graded and from a different camera. I don't think you should compare the two. The important thing for me is to show the versatility you get with your images.

1. If you throw this on your camera it makes your smaller flashes very powerful.
2. I used it for a 30 second exposure at the maximum ND and did find the x was in the image..I used live view and adjusted the shadow to add more depth to the image above where the darker "X" spot existed on the maximum darkness.
3. i will buy from them all the agin..the quality of this tool for me as a professional photographer is perfect. It evens come with alit circular case to tuck into your pocket when it's not needed.
4. It's also brilliant on the lens when using your DSLR for video work! It so much easier to spin the filter to adjust for the exposure instead of messing with your F stop or shutter speed.

Bottom Line..this thing is useful and what a bargain.

I've used very expensive Neutral Density filters in the past and this is better than those.
30 second long exposures at Noon are so much fun..buy this and go play! It's a lot of fun to use.

If you're considering buying one of these things then you are probably already aware of the shutter speed rule to have the most cinematic picture when shooting video...this is obviously impossible to attain in direct sunlight or other bright light without one of these filters! This filter serves its purpose greatly and has a very great build to it. Highly recommend!