Stereo Photography

Stereo photography is one of the simplest applications for the GeoWall. There are no one piece digital "Stereo Cameras" manufactured so we assembled one from off-the-shelf components.

Synchronizing the taking of images is an important issue. If your subject is moving while you are taking the picture the stereo image will not work well unless the cameras snap simultanously. To snap the images on our cameras at approximately the same time we use a remote control for the digital input of the cameras. Our configuration is as follows:

• StereoSnap from Harbortronics with a Digisnap. Note that the Stereosnap is simple enough to be built from scratch for a lot less than the Harbortronics purchase price...
• Two digital cameras. The StereoSnap and DigiSnap work with the Nikon CP990/995/880/885 and 5000 cameras. We use the Nikon CoolPix 995.
• Two serial cables to connect the Nikon cameras.
• To tie them together we use a Twin Camera Bar from Jasper Engineering.

For stereo photography at close to medium range it is essential to place the lenses of the cameras at approximately the same distance as between human eyes. This is easily achieved due to the swivel action on the Nikon cameras (see image). The only disadvantage is that the raw digital images are slightly misaligned and require post-processing. For stereo photography of objects at longer distance (beyond about 8-10 meters) it is attractive to increase the distance between the lenses (for example, by placing the cameras on the Twin Bar in the same orientation). Alignment is typically not necessary, but be sure to avoid to capture any objects near by as they will cause a feeling of disorientation.

Cheapo Stereo Camera for Film

Argus makes a simple pinhole camera for taking stereo pictures on film.
Advantages: it's cheap ($80) and you don't have to worry about synchronization like you need to with the dual-camera setup described above.
Disadvantages: it's cheap, no controls on exposure, and requires film processing and scanning.

Viewing Stereo Pairs on the GeoWall

Once you have made the stereopticons (stereo pairs) you can combine, and if necessary, align them with for example Russ Burdicks viewer program in Linux. Once the aligned and combined stereopairs are formed they can be viewed with viewer, or with programs like xv.

For Windows applications we use Pokescope by Monte Ramstad.

Links to More Information, Examples, etc.

• More information on stereo photography can be found at the CRYSTALCANYONS 3D GUIDE.
• Some examples of stereo photographs taken with the described configuration at the University of Michigan.
• Stereo photography at EVL.