The claim that orbs are caused by dust in front of the camera is untenable for quite a few reasons. One reason is that thousands of orb photos show orbs that are too big to be dust, too bright to be dust, too colorful to be dust, too fast-moving to be dust, too often striped to be dust, and too frequently observed in very clean air to be dust.
Another reason (discussed more fully here) is that suspended dust particles are many times too small to produce orbs. The area right in front of a camera lens has an area of about 100 million microns, but
a suspended indoor dust particle is no more than about 10 microns (giving it an area of 100 microns). So an indoor suspended dust particle will only be able to block one millionth of the area in front of the camera. Such a particle is a thousand times too small to explain orbs that may appear as 10% of the original photo height or sometimes much larger (see here for 60+ examples of such large orbs).
If suspended dust particles were big enough to produce orbs, everyone would get orbs in almost every flash photo they took. But instead 99% of all photographers get no orbs, and those with a prolonged interest in orbs get them in great abundance (a fact utterly inexplicable under the theory that orbs are tiny dust particles). The fact that 99% of all photos on any randomly selected topic you search for (such as “my cat” or “my house”) do not show orbs is definitive disprove against the claim that the dust in ordinary air is sufficient to produce orbs in ordinary photos. And almost all orb photographs are taken in ordinary air.
Anyone trying to explain orbs through any orb-zone “orbs are dust” theory is like someone trying to explain the strange death of 10 children by suggesting that the nitrogen gas in our atmosphere is poisonous. That theory doesn't work, because if the atmosphere were poisonous, everyone would be dead. Similarly, it doesn't work to claim that dust particles in ordinary air cause orbs, because if that were true everyone would get orbs in most of their flash photos.
Skeptics have some videos out there trying to back up their claim that orbs are dust. One I watched was the most ridiculous thing imaginable. It showed a man pouring handfuls of dust in front of the camera, which caused some dust orbs to arise. Of course, such a procedure is absurd, because when you do that you are creating utterly unnatural conditions completely different from the ordinary conditions under which orb photos are taken.
A more recent page by a skeptic organization is more subtle. The page shows a video showing a closeup view of dust particles in front of a high-intensity flashlight. Such an experiment is laughable because it involves an utterly artificial setup completely different from the actual conditions under which photographers such as me (and countless other orb photographers) photograph orbs. I never use close-up macro mode, and never add any type of light other than an ordinary camera-flash. Plus when I photograph I am never shooting towards some high-intensity light near the camera, but am shooting out at the scene in front of me, such as a street or a room. The photographs I take of falling water drops (which I identify as such) do not involve any special illumination (just the camera flash).
So it is for other people's orb photographs, which show orbs in front of an external scene such as someone's living room or someone's house. No orb photographer is taking closeup photos zooming into the area just in front of some high-intensity light.
I was curious – if you try taking flash photos in front of a high-beam flashlight, using the setup in the skeptic's experiment, is that sufficient to cause dust particles to produce orbs in your photos? The photos below gives the answer: orbs do not appear in flash photos taken under such conditions.
Such a result is entirely different from the result shown in the skeptic experiment, where we see lots and lots of big dust particles in front of the flashlight. There is only one way to explain this. The experimenter must have raised the dust level much higher than normal, by doing something like throwing dust around or shaking a dusty cloth near the camera. Such a procedure is utterly deceptive. It creates the completely false impression that the air we are breathing is very dusty air full of big dust particles.
Imagine if someone were to publish a video entitled “The Scary Filthy Air of New York City,” by raising lots of dust and photographing it with a high-intensity flashlight. That would be utterly deceptive, because the air in New York City is hundreds of times cleaner than it would appear in such a video. Similarly, it would be utterly deceptive to drop some dirt from your house plant into a glass of water, and to then publish a photo or video of that, with a title “The Filthy Tap Water of New York City.”
The procedure followed by these orb skeptics is every bit as deceptive and misleading as the videos imagined above. After decades of environmental studies, the size of dust particles in ordinary air is a well-established fact. Not counting freak conditions, such particles get no bigger than about 10 microns. A particle 10 microns in size has an area of 100 microns, and will block no more than one millionth of the area in front of a camera lens (which is about 100 million microns, or 100 millimeters). Such a size is way, way too small to produce a decent-sized orb in a photo. To try to create an opposite idea – that the air we breathe is very dusty – by raising lots of dust and photographing that with high-intensity flashlights is just pure deception and cheating.