I've been interested in experimenting with close-ups in VR for a while, and finally got around to building a custom VR closeup camera rig. It uses two wide angle Mobius Actioncams, and lets me get the lenses very close together (or very far apart, if I want). The are a few 3d printed parts, some wood from a cheap clipboard, some wires, resistors, a couple diodes, a few switches, and some black hot glue. Very simple.
Most stereo 360 cameras have a minimum distance from camera to subject of about 1-2 meters, in order to stitch everything properly. You can sometimes get a little bit closer, depending on the camera, orientation, and background, but that's not close enough for me!
Normally for stereo photography, you want the distance between the lenses, or the inter-axial distance, to be about the same as the interpupillary distance of the average human, or about 64mm. But for macro photography, you want to use a much smaller inter-axial. The ratio should be somewhere between 1/50 and 1/30 of the distance from the subject to the camera (I've seen some people say you can push it to 1/20). For an interaxial of 64mm, the ideal distance would be 1920mm, or close to 2 meters. If you want to shoot a closeup of about .5 meters, or 500mm, you would need an interaxial of about 17mm. With this rig, I am able to get the lenses about 25mm apart. I could probably shave a couple mm off that, but even though the lenses are pretty small, to get an interaxial smaller than that, you would need to use a beamsplitter or some other optical setup, and I don't know if that would even work with wide-angel lenses.
Here is the test footage I shot in stereo 360: • Custom VR Closeup Came...
And here it is in 6DoF:
• Custom VR Closeup Came...
*Note, throughout the video I keep saying millimeters when I mean centimeters. The interaxial of the cameras are 2.5cm, and the distances I'm measuring are also 30cm, 60cm, and 75cm. Oops!
7 мар 2018
