For me, K&F has been a staple of pro optics as they offer entry/mid price levels while maintaining a mid and high pro quality. This set was no different and in fact there is no indication that it could get "better" in a drone optical filter set.

In general I tested CPL, ND8, ND16, ND32 and ND1000 and none (except the ND1000 which had a slight vignette) showed any cast, crosses or vignetting AT ALL.

The CPL works as intended and does not remove unwanted reflections and does not modify the colors, I mean it changes the PERCEPTION of colors as it removes unwanted light spectrum, but I did not notice any color print in my testing, transfiguration or discoloration.

The ND8,16 and 32 performed excellently for the short-medium exposure of a waterfall.

Tried the ND1000 on the same waterfall but it was too dark as the sun was already setting so not sure if I was experiencing vignetting from the filter or just not enough light and user error at the end of the day.

I expect the rest of the ND4,64.2000 filters to perform similarly to their siblings, but photography is an opportunity business so I'm not sure when I'll try these out.

I like these better than the ones included by DJI with the Fly More combo, somehow I feel like they are better built and offer less haze than the DJI, it's all I need and wanted for my Air 2S optical filter requirements fulfill.