I ordered the PolarPro ND8 filter for my P4. It will help with the video (to get the shutter speed close to 60 if recording at 30fps). However, for stills (which is my primary interest) I see no benefit of the ND filter (unless it is extremely bright and beyond the highest shutter speed). In fact, it may make things worse by reducing the shutter speed and thus affecting sharpness. My guess is that people who use ND filters on the Phantoms are first and foremost interested in video, am I correct?