Inexpensive Luminance Meter With iPhone

Whitegoods Light Meter

Whitegoods Light Meter

People are always looking for a cheap way to measure the light output from their projection screen or flat panel display. I have before now said it was not a cheap thing to do. A new iPhone app changes this.

With my iPhone 4 and the Whitegoods light meter application I was able to get light output readings accurate to about 1 fL from my displays. To use this application to best suite this purpose you must do several things. First set the light conditions to Low/Medium. Next set the units to FC. Lastly, place a test image on the display and cover it with the white circle, but be sure to have some dark area visible in the image as well so the sensor can range properly.

Using this instrument to measure illuminance in FC or Lux as the instructions suggest will not work, but it is a reasonably good luminance meter. The FC readings are about +-1 fL from the values shown on my Photo Research PR-670 which is excellent for a low cost solution to indicate approximate light output from your front projection display or flat panel. The more broad spectrum the light source the better. Errors in measuring primary and secondary colors where unacceptably high compared to white for this reason.

Here is a link to more information on this.

W. Jeff Meier

ISF and THX Certified Home Theater Consultant

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