During the tour I explain, under these (tour) conditions, take three or four pictures in a row, as quickly as the camera can handle, without moving the camera. We are looking for stuff that does not appear in every picture. If it appears every time, we know it has a normal (rather than a paranormal) explanation. It is a reflection, or a bug, or fog (humidity). We are looking of stuff that only appears in one image, or sometimes an object that moves.
Use a million candle power spot light to shine into the air – if you see particles floating in the beam of light, these are the orbs you capture, and they are environmental, not paranormal. If you see orbs in the beam of light, put away your camera and turn on your voice recorder, as dust orbs have no effect on the recorder.