Some of you have sent in photos of shimmering specters you’ve caught on your cameras and asked if they were ghosts. So I wanted to show you photos of anomalies that are, and are not, ghosts.

These two images below are not ghosts.

Cameras are fun to work with and since their start they sometimes have been used to make double exposures and create ghost-like scenes. There are several ways to create this effect with digital cameras, including selecting to make a double exposure; creating an HDR image from two different photos; and merging several photos as layers, to make them look like ghosts.

Some ghost-like images can occur accidentally – for example, you have opened up the shutter speed to take a photo some place where it is dark and someone passes by as the camera lens is open. You may not even be aware of this, if you are in a public place. This can look like a fog if the person walked very fast – as shown to the left, where I walked very fast through the timed shot.

You can get a ghost with features if the person walked by slowly.

In the photo shown to the right, I used a Nikon D80 on a tripod, opened the shutter speed to “bulb”, attached a cable and locked it in open position. I started by sitting in the chair, then very quickly stood up and exited; the timer ended showing a faint image of me – the “ghost” – in a chair.

Working in Photoshop, you can create something even more sophisticated, by superimposing several images then reducing the opacity of the top image, thus creating a ghost-like visage over a solid scene.

So sometimes a novice photographer may feel they have captured the image of a spirit or entity, but it may be this simple technical explanation, one an experienced photographer can spot right away. And sometime folks make such images on purpose, for the fun of it.

Now shown below are two authentic photographs of ghosts. The photographers were place winners in our 2011 and 2012 photo contests.

The first, by Cindi Probst, shows plasma in the shape of a revolutionary war soldier (seen better when blown up very large), appearing on a clear day in a revolutionary era graveyard. The plasma is very clear, and so is the surrounding image: this is one mark of a good ghost image.

The second, submitted by Kory Gunderson, shows a friend photographed at a so-called haunted restaurant; the white anomaly only showed up in photos of her friend (see insets), and in the large image, the friend is stationary but the white plasma is moving very fast and has a face showing. This is another way to tell if you caught such an image; the stationary status of everything in the photo except the plasma which was moving faster than the camera snapped the image.

Have fun trying these yourself!