Remote recording
Start and stop recording on a computer running Hand Tracker with Remote recording on (a camera rig on a Raspberry Pi, say): pick its cameras and mode, fill in the take details and watch each camera live.
No network between them? A computer with remote recording on can be reached over Bluetooth when it's near by (a Raspberry Pi set up with pi/bluetooth-setup.sh, with its hotspot's password).
No network between them? A computer with remote recording on can be reached over Bluetooth when it's near by (a Raspberry Pi set up with pi/bluetooth-setup.sh, with its hotspot's password, asked for the first time). Faster, with live pictures: pair this phone with it in Bluetooth settings (once) and turn on Internet access for it there (under its ⚙); not while a VPN such as Tailscale is on.
Over Tailscale (from anywhere, with Tailscale on this device): its Tailscale name, such as pi or pi.your-tailnet.ts.net, or its 100.x address. No code is needed: only your own devices can reach it there.
On the same Wi-Fi without Tailscale: paste the address under the QR code in Hand Tracker's Remote recording (it ends in #k= and a code), or scan the QR code with a phone's camera. The code is what that page needs.