Eyewear for real-time stereoscopic 3D monitoring on set — each lens filters one image to the corresponding eye. Live depth-effect control during shooting.
On a 3D set, you need a reliable method during shooting to control what the camera is actually capturing – not just technically, but also dramatically. Polarized glasses do exactly that: they separate two superimposed images displayed on the monitor or the matte box preview so that each eye sees only its correct image. This works through different polarizing filters in the two lenses, which are synchronized with correspondingly polarized image material (e.g., from dual-sensor 3D rigs or beam splitter setups).
In practice, you sit on set wearing them, look at the monitor, and immediately see if the axis convergence is correct, if the interaxial distance is rendering depth properly, or if objects are unpleasantly jarring. Without the glasses, you only see two superimposed, blurry images – your brain can't interpret what's happening. With the glasses, the 3D fusion happens in real-time, just like for the final viewer. You can identify focus problems that only manifest in depth, or ghosting effects that are invisible in the 2D preview.
Important: The glasses are not universal. Depending on the 3D capture system used – whether it's passive polarization technology, active shutter systems, or interference filters – you need the right glasses for the right source. In older film 3D productions (e.g., with Pace Fusion cameras or Arri Alexa Studio in 3D modes), polarized glasses were standard for video assist. With modern LED monitors with higher refresh rates, the glasses must be compatible, otherwise, it will flicker or the separation will break down.
The biggest advantage: You protect yourself against nasty surprises in post-production. 3D convergence errors or incorrect interaxial settings are still correctable on set – in the grading suite or during 3D alignment, it becomes expensive. Good polarized glasses cost 200–500 Euros and save you thousands in post. Make sure the glasses are light enough for long set days and that your monitor is actually optimized for polarized signals – cheap displays quickly lose image quality under polarizing filters.