Beamsplitter Macro

Closeup photography in stereo requires special equipment. The cameras below were developed for use in photographing fluid motions, but they also serve well for general macro work. The problem with macro is simply that in order to satisfy the 1/30 guideline (camera separation ~ 1/30'th distance to subject) you have to put the cameras very close together.

We built two different units to do this sort of thing (initially for fluids research, but they turned out to be more generally useful). Both use the basic idea of placing a 50-50 (equal transmission and reflection) beamsplitter in front of the lenses. This is shown schematically below.

Beamsplitter Macro 3D Two cameras are mounted in a perpendicular orientation. A 50% transmission, 50% reflection planar beam splitter is mounted at the intersection of the central rays. The size of the splitter plate is determined by the focal lengths of the lenses you wish to use. A large plate is required for wide angles.