These two variable filters from K&F are an excellent alternative to the filter sets from other brands here on Amazon. For their problems with color shifts, enter the following search terms: “Mini 3 Pro ND Filters, Which Inexpensive Filter is Best?”
Normally, the ND2-ND32 is sufficient even in strong sun and there is no need to change the filter! You test shortly before the flight and set the appropriate value by ring marking. The adjustment is freely circumferential without stopping or snapping. The effect of increasing neutral density is achieved here by twisting two polarizing filters located one above the other.

Perfect fit: Both filters are very easy to attach to the lens, snap into place and hold tight!

White balance: I did not notice any significant differences in the white balance value between the individual ND levels. The color chart was photographed in each case by Datacolor.

Color behavior: K&F's promise that there are no color shifts was also kept. This was also checked in Lightroom Classic. Other filters cannot keep up with this and you may have to create and apply luts with appropriate color corrections using the Datacolor Color Charts or Spyder Checkr.

Sharpness and vignetting: The image remains absolutely sharp in comparison without the filter and vignetting is not visible.

Light reflection behavior: In backlight, no disturbing reflections were visible. The multi-coating does a very good job here.

Autofocus: The autofocus works well from a distance of 1m, even with a higher ND value. At a very short distance, I had slight problems taking pictures of the color chart from ND 32 and the focus was set too far back by the camera.

Weight: The filter weighs 1.5g and replaces the camera's lens protector, which weighs 0.7g. The drone therefore weighs 0.8 g more with the filter and therefore remains safely in the range of under 250 g total weight and can continue to be used without a drone license.

Storage box: Here too, K&F stands out from some other suppliers, because the original cover fits completely into the small plastic storage box from height and is therefore loss-proof.

Conclusion: With just a single, adjustable filter that can remain on the camera, you get significantly better video recordings with the 180° shutter rule, which look more cinematic. The overall picture is improved in terms of dynamics. The 32-512 ND filter is particularly interesting for photography when it comes to longer exposure times.