Our eyes help us to perceive three dimensional depth by having two visual sensors, separated by about 100mm of distance. This slight difference between the right and left eye is enough for us to see what is in front or behind the things we see. Since most cameras have only one lens, they show a two dimensional view of the scene.
Stereograms were invented during the early days of photography, and used two cameras, slightly offset, to show three dimensional scenes.
This project allows you to take two pictures with two cameras, and get the results of a 3D image. This rig was built with K’nex, but it can also be built with LEGO bricks, and can be made of 3D printed parts or even two cameras taped to a small board.
Some design considerations to keep in mind: the cameras need to be parallel to each other, the lenses need to line up side to side, and if your subject is moving, you need to keep care that you press both shutter buttons at the same time. Simultaneous shooting is less of a concern if you mount your rig on a stationary object, such as a tripod, and the subject doesn’t move.
Once you take the pictures, you can view them by showing each on the screen of the phones or cameras. Eventually, you will want to put the pictures on a computer and view them side by side. To do this effectively, you will want to bring the pictures into a photo editing software application, and paste the picture from the left camera next to the picture from the right.
To view the pictures, look at the two pictures side by side. You will need to cross your eyes slightly, until you see a middle image. The ‘third image’ in the middle is a combination of the left and right images, and you should be able to see that there is a front of the scene and a back. If your head is too close to the pictures, it will be difficult to cross your eyes enough.
Choosing the subject to photograph with this tool may take some practice. You want to have a good foreground and background of the image. You may also find that if the foreground of the subject is too close to the camera, the images don’t combine well.
There are photos of this project.