Using Google Cardboard as a Stereoscope

Homemade Cardboard Viewer, rear view phone mount area

As a device to view 3D photos, the Google Cardboard VR (Virtual Reality) viewer has its limitations. The lenses do not have enough field of view to completely see a side by side (parallel) 3D photo that fills the entire display on a phone. I think the design intention was to have an immersive experience and that the cardboard wearer would move to view an entire image as it shifts corresponding to head movement. Cardboard is foremost a Virtual Reality viewer, not a stereoscope.

Berezin Stereo Photography Products has a  rectangular lens (product 3791) with a better field of view for viewing parallel 3D photos on phones. Having used this lens with my phone I found the experience viewing 3D photos much better than with the Cardboard lenses. This lens has very little barrel distortion so software corrections are not needed.

Berezin 3DVu Lens, before hacksawed in half
My next step was to mount the Berezin 3D viewer lens in a Cardboard viewer. I  downloaded plans for making my own Cardboard viewer and altered the design to fit the lenses. This required rectangular  holes for the lenses and increased lens distance from the phone for normal sighted persons.

The Berezin 3D viewer lens come in a plastic frame that does not have enough lens separation for Cardboard. I solved this by cutting the frame in half with a hacksaw and mounting each frame half and lens in my Cardboard. I did not try to remove the lens from the plastic frame because I feared destroying the lens. Conveniently, the plastic frame provided a mounting surface to hot glue to the cardboard.  I increased the distance from the lens to the phone by 38 mm, adjusting the cardboard viewer layout plans before I cut out my custom version.

I'm very pleased with the resulting stereoscope. My 3D photos look much better when Cardboard is used as a simple stereoscope because I can see the full screen image without moving. I also found my modified viewer better for looking at photo-spheres and other VR Cardboard apps with head movement too. The trade off  for my Cardboard viewer with the Berezin lenses is that the screen is not fully immersive for virtual reality, that is, I can see the black walls inside the viewer. But I did not find this to be a distraction.

Morris Arboretum Insect Sculptures 3D Photos

David Rogers (artist), Big Bugs Exhibit: I photographed these side by side (parallel) stereo 3D photos of insect sculptures on display at the Morris Arboretum, Philadelphia, PA, August 30, 2013.

You will need a stereoscope viewer to see in 3D.