I ordered the 67mm size because it matches the native thread size of my largest lens with the largest diameter threads, a 70-300mm used on my full frame mirrorless camera. That lens is used almost exclusively for shooting outdoor activities including a few happening on the water in bright sunlight and the watercraft are also bright and moving quickly, kicking up a lot of water. The ultimate in lens and filter quality is not what I strive for based on my personal goals with those shoots. Landscapes and creamy waterfalls are not high on my priorities.

When I do paid shoots it's mostly of still objects under controlled conditions so I have the means and the time to get the exposure I want without filters. Looking into this K&F Nano D series it seems to be the grade and cost suitable for my realistic budget and requirements.

This ND filter will very likely stay on the lens most of the time. When it is completely threaded onto that telephoto the markings are unfortunately down at about 7 o'clock, out of sight. I will be tempted to experiment with some ultra thin shim of some sort to have the filter threads firm up when the markings are visible up top where I can quickly refer to them. The knurled grip on the ND filter is a good size for larger fingers. The rotation action of the adjustable ring is really smooth and definite, with hard stops at the extreme ends of travel at '2' and at '32' stops. There are no intermediate detents within those limits.

The packaging is a plastic case significantly larger than the filter itself which is nested in a cutout of thick soft foam. If I had a choice I would prefer the product came in a padded wallet that takes up less room in my gear bag and would drop into a jacket pocket easily. Since I probably will keep the filter on the lens it's not a deal breaker, just a preference for my habits.

I have had a semi-pro camcorder for years with a built in stepped ND filter operated by a thumb switch and that's been really handy to "dial back" the sunlight very quickly without disturbing any other settings while I continue shooting. This adjustable ND filter will add that convenience to my telephoto on the mirrorless camera.