Some excellent stereo images have been made using a single camera. The basic idea is to shoot two exposures, the second of which is displaced laterally from the first by the appropriate “stereo base”. The stereo base determines the amount of stereo effect that will be apparent in your stereo photograph. The “normal” stereo base of human eyes is about 65mm, the measured distance between the pupils of a persons eyes. If you want to have your stereo photograph appear as natural as possible, the camera should be displaced laterally 65-70mm for the second exposure. When shooting close-ups, the stereo base should be approximately one twenty fifth (1/25) of the subject to camera distance. Increasing the stereo base beyond normal will exaggerate the stereo effect and has been very effectively used to depict distant scenes and cityscapes. It is referred to as hyperstereo.
Imagine each of your eyes as being a camera, which in fact they are. Each eye sees a slightly different picture while focused on the same point. When the two images (one from each eye) are fused by the brain, a single image with depth is experienced. In stereo photography we can simply take two separate images and present these two different images (one to each eye) and the brain will do the rest. The general rule of thumb is that the stereo base should be 1/30 of the distance to the subject. If the subject is a mountain a mile away some care will have to be exercised in establishing the stereo base so as not to make objects in the foreground difficult to view because of the excessive stereo effect. In this case, a stereo base of as little as six inches will give definition to the mountain. Experimentation is half the fun.
Once you have made your stereo pairs, you will want to learn how to edit them and view your stereo images without the aid of a stereo viewer, a method called “free viewing”.
In the series of stereo images that I present in my image gallery all were taken with a single camera unless otherwise noted in the text that accompanies each pair of stereo images. Please use these images to practice how to free view stereo images after reading the instructions on how to. Both parallel and cross eye viewing of the same images are shown. All of the outdoor scenic photos were made using the “cha-cha” method (explained below). The “Rocks and Trees” and the “South Sister” images were taken with an Olympus Stylus point and shoot film camera. Digital images were produced from scanned 3.5″ x 5″ prints. The “Cochise Stronghold” and “Grand Canyon” images were taken with a single digital camera, a Fuji FinePix 2400 point and shoot. In the “cha-cha” method the first photo is taken with the weight on one foot and then the weight is shifted to the other foot just before the second exposure is made. This movement has the effect of displacing the camera laterally approximately 3 inches or 75mm. Care must be taken to keep the camera level for each exposure and to try to keep the lines of sight to the subject parallel. The flower photographs were made using a single digital camera attached to a swing bar to keep everything lined up and precisely positioned between exposures. All images were edited in a photo editing program such as PhotoShop or GIMP to set the window, properly align everything, crop the image, and eliminate any dust bunnies.