Throw ratio

Definition

Throw ratio is distance from the lens to the screen divided by the image width (not the diagonal). A 1.4–2.8 zoom on a 2.5 m wide 16:9 image sits between 3.5 m and 7.0 m. Short-throw and UST lenses use ratios well below 0.5. Always use the manufacturer’s min/max, not a forum guess: offset, zoom memory and lens shift eat the theoretical window. Recalculate if you change aspect ratio.

Calculators that use this

• Screens & projection

  Projector Throw Distance Calculator

  Turn a throw-ratio pair and screen size into the minimum, maximum and mid-zoom mounting distance.

• Screens & projection

  Screen Size to Aspect Ratio Converter

  Convert a diagonal and aspect ratio into width, height and area for 16:9, Scope or 4:3 masking.

• Screens & projection

  Projector Brightness (Foot-Lamberts) Calculator

  Estimate on-screen foot-lamberts and nits from lumens, screen gain and image area. Compare with cinema and HDR targets.