The filter comes in a very elegant packaging with magnetic closure and also has a small plastic box for transport. The filter can be easily turned on and off the lens, intended for maximum setting 3-4 full f-stops. You can see the effect best in backlight or strong contrasts in the subject, I look forward to testing the filter in the midday sun in the summer.

I ordered this to use with my favorite walkabout lens, in an effort to get myself back in the habit of taking photowalks on a more regular basis. I had to stop because of my mobility issues, and it's taken me years to get back to a point where I might be able to manage a slow 20-minute walk on less-than-smooth ground, but it's time.

The filter size is accurate and it screws easily into my lens. The coatings are smooth, with no ripples, bubbles, or uneven appearance at any point in the rotation. The ring rotates easily and smoothly, and it's easy to see the glass visibly darken as it's rotated.

The photos come out crisp and clean, without the haze that's often attributable to unpolarized light, and unlike with some lower-quality ND filters, without any hint of a moiré pattern.

Challenge number 1) The K&F Concept 77 mm Variable ND filters I purchased arrived later than promised and I was not able to use it for my 9 day photoshoot. Challenge number 2) It fits on my camera lens but needs time and patience to attach to the lens but it does fit. Challenge number 3) No positive stops, no detents to let you know how far you've gone (my ND filter 1.5-10 stops). In addition, if you are invested in using your lens hood while shooting, it won't fit with these ND filters.

I'll be using the ND filters on my next photoshoot and will submit an update to my review.

The build quality and clarity on this filter is excellent. The adjustment ring is a little snug, but I expect that to loosen with time. I can't tell a difference between this filter and my higher-end ones.

Spoiler Alert: My ratings mean nothing. I haven't bought this filter yet. However, I see the question in my headline both in the Questions about the product and in several users below who ding the product because it uses two polarizers or the filter doesn't work with a CPL. The answer to the question above is misleading and those reviews below aren't fair. Above, the seller says you could add a CPL filter to this VND filter, (true) but, based on what I've read, the results of doing will be very unreliable. Here's why: all VND filters work using two polarizing elements. (Don't complain when your VND has two elements.) One element is a linear polarizer and one is circular. As you turn one, the filter darkens or lightens. Now imagine stacking a CPL filter on top of a VND filter. This really creates three polarizing filters - a linear polarizer, a circular polarizer, and another circular polarizer. That's a lot of polarization for a photographer to keep track of, especially if your VND filter is dialed down so you can't clearly see the shot, which happens with ND filters. Let's pretend you wanted to shoot waterfalls with a VND filter and a CPL filter stacked on top of it. Imagine creating this shot given what I've told you. I couldn't do it reliably. (I might get lucky.) So, if I wanted to shot an image that required both a ND filter and a CPL filter, I'd probably get much better results with both a standard ND filter, which removes the polarization, and a CPL. I hope this helps potential buyers of this item. I'm asking for this filter as a birthday gift. So I'm not a buyer yet, but I hope my wife will be.

As others have stated, when used correctly this filter does not produce the dreaded X. Nor does it have any color cast that I can see. The quality of construction is very good, and the ring rotates smoothly without being too tight or too loose. Quality product. Glad to have it.

K&F Concept's range of filters have never let me down and neither has this variable ND3-ND1000 ND filter.

This filter maintains accurate color throughout the entire range unlike other filters I've used, which is a huge plus since it saves me time in post by not having to mess with color correction.

There is no dreaded "X", even when I intentionally went too far. While I'm not sure the stated range is entirely accurate, it is close enough and provides a ton of functionality, especially given the low price point compared to other filters that offer such a great density range.

I don't experience any vignetting with this filter, which isn't as slim as others I've used. But I rarely get vignetting when using the 18-140mm lens that I tested this filter with so my experience may not be applicable to different lenses.

Stops are clearly marked on the filter, and the adjustment is smooth with a little resistance that offers good control while shooting.

That said there is one thing you should know about this filter - YOUR LENS CAP WILL NOT FIT. I wish they included a lens cap with this filter or at least stated this clearly in the description, because you'll have to either print a new lens cap or buy one that will fit over this filter.

For the 67mm filter, you'll need a 72mm lens cap.

Overall this is an excellent value for a high quality filter. I doubt you'll find another variable ND filter with this range and at this quality for a lower price.

What can I say? This is a great tool. It gives so much flexibility for ISO speed and shutter speed. It has low distortion and internal reflection. This is a MUST on the front of any lens and the quality is amazing for the price!!!!