Can cameras capture ghosts?

Real ghost caught on camera!

CCTV catches ghost on camera.

Surveillance video of ghost.

I am sure you have seen those headlines and others. Almost every day there appears to be another ghost caught on camera. But, is there some kind of special material or mechanism that allows cameras to see what our naked eyes can't? 

Let's start with an easy thing: Orbs - those white balls appearing on photos like this one. Some still say that orbs are the spirit of dead people, but this has been widely debunked even by paranormal investigators themselves. This is one of the best explanations of orbs:

"Orbs most often appear on camera when a piece of airborne dust, an insect, or a water droplet is close to the camera, outside of the depth of field, and the flash source is no more than a few degrees away from the axis of the camera lens.  This causes the object to be brightly light but way out of focus, resulting in a semi-transparent whitish circle."1. 

People *want* to believe that orbs are spirits because they may have recently lost a loved one (and the orb appeared at exactly their favorite spot/location - it can't be coincidence, riiiiight?) or because the whole scenery is considered "eerie" or "creepy" like the picture here or "heavenly" (so there must be something otherworldly there, riiiiight?).

(c) Ghostbusters film

But what about those "special tools" used by ghost hunters? Infrared Thermometers and motion detectors are exactly like your eyes and work the same way except they measure the temperature of an object. "Variations of IR readings inside a room are merely showing temperature gradations on the walls, caused by heating and AC, insulation variances, studs, wiring, or pipes behind the wall, radiant heat, recent proximity of another ghost hunter, sunlight, temperatures in adjacent rooms, or countless other causes." 2 

It is easy to fake stuff on TV, just like the movies you go to see. The footage can be edited, the background music is used for effect, the actors can say whatever they want to make you believe (and many people want to believe, that's why these shows have such high ratings). There's a recipe to ghost hunting shows, which you can read here. Another thing that bothers me is why they are almost always investigating in the dark? What's so special about the dark? It's just scarier, not that it really makes it easier to "see" or catch anything.

There are many, many claims of ghosts on cameras, so we can't analyze each one. But, some of the most famous ones have been analyzed and with some scientific thought they have been proven false. So, the same explanations can be used for a lot of the other ghost on camera stories out there.

Some sites to check out are Snopes.com and Skeptoid.com and do a search there for "ghost", to read the logical explanations.

For example, video of the "ghost" caught in an Ireland school opening doors and knocking things over.

Or, how "ghost photography" started. 

Also, why do we think that just because we can't explain something or can't explain it right away, it immediately and definitely means it is paranormal (aliens, ghosts, etc.)? There are a lot of *natural-occurring* things in the *natural* world that we still don't understand and that we cannot explain. That is not PROOF of anything paranormal or supernatural.

Cited:

1. Skeptoid episode 4029.
2. Skeptoid episode 4081.

More good reading:

- 6 mistakes in ghost hunting: CSI-COP.

- 10 famous paranormal videos debunked: LiveScience.

- The science of debunking ghosts: Collegian.
- 10 Scientific Explanations for ghosts: Gizmodo.