Bullet time photography allows a single instant in time to be captured by multiple cameras, enabling one to “spin” around the subject virtually after the fact. It's perhaps most recognizable from The Matrix film, and more recently Eric Paré has been experimenting with the technique using an array of 15 Raspberry Pi Camera v2 modules and the Xangle Camera Server software package.
As seen in the video below, Paré is by no means a stranger to bullet time, having created some stunning effects with more expensive and physically larger digital cameras. The Pi Camera's tiny size, however, allows 15 of them to be stuffed very closely together, for what is his best density ever on a multi-camera rig.
Each Pi Camera runs to its own Pi 3B+, sending photographic information to a laptop via Ethernet. Photos can be initiated with a simple handheld Bluetooth presentation trigger. No custom hardware is needed for the Pi Camera setup itself, though a custom PCB was implemented to trigger an external flash.
The cameras are mounted on a length of aluminum extrusion, using a custom acrylic plate and 3D-printed adapter. There was some struggle getting the devices calibrated correctly, but after sticking the lenses directly to the boards, the quality has improved quite a bit. The system is also compatible with the Pi HQ camera, which, while larger, should provide a huge jump in quality!