'Orbs' are the most common anomalies captured on photographs. These usually show up as transparent or translucent ball of light. There is a common belief among some people that orbs are an early stage of a ghost manifestation, however research seems to suggest that the majority of orb photographs can be rationally explained as being tiny airborne particles such as dust, pollen, moisture etc.
If any of these are within the focal range of the camera lens at the time of the photograph being taken, the flash that fires on the camera will sometimes reflect back from the airborne particle giving it the orb like appearance on the photograph.
There are certain orb photographs that do have more credibility though… For example: If we could capture a photograph containing an orb that is partially hidden behind a static object like a chair, table, or some other stationary object in the photograph. This would then give it a depth of perspective meaning if the chair was in the centre of the room and the orb was half hidden behind it, we could then conclude that it was not a tiny airborne particle within the focal range of the camera. We could also gauge it's size and distance.