Cases include nighttime and underwater photography, when a bright light source and reflective unfocused particles are near the camera.
[5] The artifact can result from the backscatter or retroreflection of the light from airborne solid particles, such as dust or pollen, or liquid droplets, especially rain or mist.
[2][4] The image artifacts usually appear as either white or semi-transparent circles, though may also occur with whole or partial color spectra, purple fringing or other chromatic aberration.
[2]In underwater scenes, particles such as sand or planktonic marine life near the lens, invisible to the diver, reflect light from the flash causing the orb artifact in the image.
[10] Prominent paranormal investigators such as Joe Nickell have agreed with skeptic-debunkers' assessments that orbs result from natural phenomena like insects, dust, pollen, or water droplets.