Synchronizing exposure time of multiple CSI cameras using Raspberry Pis

The project is about 3D pose reconstruction, meaning the more synchronized the frames, the better (non-interpolation) triangulation can be done. My current setup is two Raspberry Pi 4B with each a CSI Arducam camera module IMX708.

Is there a way I can “tell the camera” an exact time I want the frame to be shot? Or is there an internal oscillator that just streams frames and can’t be synchronized between cameras?

The issue is not the Pis clock alignment, more the subframe alignment.

Thanks in advance for any tips or help 🙂