Photo date: September 21, 2016. Photographer: Mark Mahin.
I took the photo below while photographing ordinary drops of pure, clean water falling against a dark background. In the foreground we see a water drop that was about five inches from the camera. In the background we see a large orb with an apparent size of about five inches. This orb took up 36 percent of the original photo height. It's not a drop of water on my camera lens, because it didn't appear in the next photo. The orb cannot possibly be a speck of dust very near the camera, both because it is behind a water drop five inches from the camera, and also because of its large size. I estimate some particle would need to be 3000 microns to appear this large, but floating indoor dust particles are only about 10 microns.