K&F Concept 67mm Putter Variable ND Filter ND2-ND400 (1-9 Stops) 28 Multi-Layer Coatings Import AGC Glass Adjustable Neutral Density Filter for Camera Lens (Nano-X Series)

ND filter works perfectly! Used it for my 16mm lens (24mm full frame equivalent) on a aps-c camera. Zero vignetting all the way down to the last stop. Only shows X when you go past the ND400. Even directly only ND400 there is zero vignetting. Perfect for my Sony ZV-E10 II. Highly recommended!

Great filter. High quality, robust build that really reflects the care missing from so many products these days. Even the carrying pouch is a cut above, which comes with a drawstring that ejects the filter without needing to leave fingerprints on the glass.

K&F filters are fantastic, work as promised with zero distortion. Made with Japanese optical glass. Reasonably priced filters that are excellent!

I think this is one of the best products for content creators, I recommend it to you.

Camera - fx3 in slog3 shooting in 4K 4:2:2 10bit 24fps 1/50, 640 iso f1.4 on a 40mm sigma art.With the nd set on its darkest setting with the above settings on a very bright day it’s slightly over exposed with the aperture wide open. If I close it a little to f2.8 it’s a little under exposed in which i need to open the nd filter slightly.This does work really well for video work, it does have a slight color cast but it can be remedied either by adjusting your wb or just fix it in post. It’s negligible if your shooting in log. It doesn’t have hard stops so it does have an x if you go past the working ranges. And if you’re new to ND filters without stops, this doesn’t mean that the filter doesn’t work, it just means that you have to pay attention not to go past. Another thing worth noting is that the markings on the filter are not accurately lined up so it’s best to just either make your own markings or make notations on the ring to tell what is fully closed and what is wide-open without the X appearing. It’s honestly a great ND filter minus the lack of hard stops. The only other annoyance is that it doesn’t come with a cap but K & F does sell one for their older models that will fit this newer model, but you will have to cut a notch in the cap for it to fit correctly. I added a picture of this. I chose this over going with a polar pro due to cost effectiveness, and I’m not upset about it. There is another version of this filter that goes one stop darker up to nd1000 that I was considering getting. But my fastest lens is a 1.4 prime. If I had anything less than that and I wanted to shoot wide-open I would get that filter instead.

Very easy to add to the front of the UV filter on my lens. Makes taking pictures of waterfalls very easy since you can change the filter density to compensate for different shutter speeds (I generally shoot from 1/2 to 2 seconds).

Not what I expected

It has a smooth operation and a wide range. .