I have found 16 and 64 to be most commonly used ND filters. You have to really hit the correct filter with the drones that have a fixed aperture and for the life of my I can't figure out why DJI chose those strengths for the Mini 5 Pro. I have never used a 128. I've used a 1000 for stills of waterfalls. Any thoughts on that set? I am leaning toward getting a more complete set from Freewell.