# Luminosity Conversion Question

1. May 18, 2006

### alexa179

Could someone help me out with a conversion question.

How do you convert 290mcd to candelas/meter square?
Or what additional information do I need to make the converstion?

Thanks!

2. May 18, 2006

### clive

If "mcd" means milicandela then a "conversion" between these two quantities is impossible. I think you have to compute the luminance E (in cd/m^2) at a given point on a surface from a source with a given luminous intensity I (in cd). If this is the case, the equation you need is
$$E=\frac{I}{r^2}cos \alpha$$
with r the distance from the source to the point and \alpha the incidence angle (measured from the normal direction).

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