How do you build a beam splitter for 3d cinematography?

To build a beam splitter for 3D cinematography, you need a half-silvered mirror that allows light to pass through while reflecting a portion of it. This mirror is placed at a 45-degree angle between two cameras or lenses, allowing each camera to capture a slightly different perspective of the scene. Ensure that the cameras are calibrated for alignment and focus to achieve a cohesive 3D effect. Additionally, proper lighting and synchronization between the cameras are crucial for optimal results.