3D TUTORIAL: Aligning and Cropping Stereopairs

This is a ‘pure’ geeky (and unfunny) post for my stereophotography friends. If you’re unfamiliar with it, briefly: stereophotography is the art of taking 3D pictures, usually via a stereopair: two pictures—each representing the view of one eye—which, when fused, recreate the 3D scene. See a ton of examples I have made here: http://instagram.com/WorldOfDepth

Taking a Stereopair

Though there are specialized dual-lens stereocameras, you can take a stereopair with any camera in a sequential fashion: take one photo, then while keeping the camera pointed straight ahead, move to the left or right, exactly perpendicular to the camera view, 2-3 inches or 4-5 cm, and take another. You want:

• the magnification/zoom to be constant (don’t move closer/farther to/from the subject) 
• the top and bottom edges of the scene to be constant (don’t move or point up/down)

When you move sideways, things at the opposite edge of your view will get cut off slightly, of course; this is OK. Do NOT pivot the camera to compensate (this creates trapezoidal so-called keystone distortion).