I bought the K&F magnetic CPL filter to mount on a Sony 18-105 lens. Although the filter is excellently made (even the magnet attaches well to the support ring), the main problem is that the lens cap (72mm diameter) does not attach to either the filter or the support ring, leaving the glasses unprotected. The return has begun.

Good ND Filter for the 18-135mm Sony E-Mount Lens

Used on a Sony Alpha 7III (FE mount), this ND filter is superb. The finishes are very good, the notched indicators on the ring allow you to calculate the number of stops.
I mainly use it for videos, I didn't notice any “cross” effect even at max.
It's confirmed!

In use on the Sony 20mm F1.8G and does exactly what it's supposed to do. Use it for videos in the sun

It's my first ND filter and I'm totally satisfied, it's made of glass and looks high quality.

I've used it with my Sony A6000 and haven't noticed any overly noticeable dominance or aberration.

It comes with a leather sheath lined with a soft fabric inside; Velvet type, practical to be able to transport it without fear of scratches.

I bought the K&F Concept ND filter for my Sony Alpha 7 III. I use the 67mm version.
The filter arrived the third day. Everything was well packed and undamaged.

The processing is really impressive. Very clean glass and no scratches or anything like that.
The intensity of the ND filter can be continuously adjusted from ND2 to ND400.
I took a few test photos with the filter and am absolutely satisfied.
The only drawback for which there is a star deduction: At the maximum filter level you have a bluish shimmering X in the photo. This is a bit annoying, but if you turn the intensity down to just below the MAX level, it disappears again.

All in all, you can't go wrong with the ND filter from K&F Concept. At a reasonable price you get a universal ND filter. I give it a clear buy recommendation and because of one shortcoming 4 stars.
I hope I could help :-)

The K&F Concept ND Filter work great and the build quality is fantastic. Bought it for my sony a6300 kit lens and it works flawlessly.

I received this variable ND filter today and immediately took photos with my Sony A7 III and the 24-105mm f/4.0 lens. I exposed manually and deactivated the live view display. The results were VERY convincing. This combination will soon also be used for video filming.

I had had very bad experiences with another variable filter a few years ago because it created colored streaks in the photos, so I had to return it.