Tested PolarPro Neutral Density 2-Stop filter today: and generally I like results, but with some problems. As I wrote earlier, filter fits very tight, so after seeing video on my computer, I suppose I didn't fit filter fully: in video are seen blink circle from lenses into filter glass (I suppose). It better seen in lower right and left parts, not so visible in sky area. In my opinion, result is not acceptable. After seeing video, carefully cut a bit of little holding plastic tabs inside filter with knife, and now filter seem fits fully and more comfortable, so hope blinks will be gone. So need to do another test

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This is video from today flight (nothing special, just test flight. Also no edit, straight from Phantom, only made video shorter). Please take a look: