ToolHuts

Praktische tools voor nauwkeurig werk

Projectorhelderheid & Foot-Lamberts Calculator

Schat foot-lamberts op basis van geleverde lumens, schermformaat en gain, of bereken omgekeerd het benodigde lichtoutput.

in
%
fL
Estimated screen brightness41.0fL
Approx. luminance140cd/m²
Screen area42.7ft²
Delivered lumens used1750lm
Rated lumens needed977lm

Werking

How to use it: enter screen size, rated lumens, an estimated delivered-output percentage, screen gain and your comparison target. This keeps marketing output separate from the lumens assumed to reach the screen.

Formula. Foot-lamberts = delivered lumens x gain / screen area in square feet. Approximate cd/m² = fL x 3.426. Reverse rated lumens also accounts for the entered delivery percentage.

Example. A 2500-lumen projector modeled at 70% output delivers 1750 lumens before screen gain and area are applied.

Voorbeeld met huidige invoer

Het resultaat hierboven gebruikt precies deze waarden. Deze momentopname wordt bij het afdrukken opgenomen om de uitvoer met de oorspronkelijke metingen te controleren.

Screen diagonal
120 in
Aspect width
16
Aspect height
9
Rated lumens
2500
Estimated delivered output
70 %
Screen gain
1
Target brightness
16 fL

Hoofdresultaat: Estimated screen brightness: 41.0 fL.

Vóór gebruik van het resultaat

  • Measure from the datum or reference edge described by this tool, and do not mix inside, outside and centerline dimensions.
  • Keep inputs in the displayed units and preserve more precision than the final cutting or purchasing tolerance requires.
  • When the result is close to a limit, verify it with a test piece, field measurement, manufacturer drawing or qualified project professional.

Beperkingen

This is an idealized uniform-screen estimate. Calibration mode, zoom, lamp/laser age, optical losses, screen directionality, ambient light, contrast and measurement position affect the real image. Measure the installed system when brightness matters.

Veelgestelde vragen

Why include delivered-output percentage?

Rated maximum output may not match the calibrated picture mode you use. The editable percentage makes that uncertainty explicit.