Relationship of "mcd" to "Lumens/Meter"?

[Forge]

What is the relationship of "mcd" to "Lumens/Meter (squared)"?

Thanks!

 

[Quickbeam]

You will find all of your answers here, Grasshopper

:
http://www.intl-light.com/handbook/

 

[Forge]

Get real! Who could understand that but a scientist!!!!!!!!!!???????

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Quickbeam:
You will find all of your answers here, Grasshopper

:
http://www.intl-light.com/handbook/<HR></BLOCKQUOTE>

 

[**DONOTDELETE**]

Nothing wrong with trying to be a scientist!

Nevertheless, I will endeavor to answer your question in a simple way.

Millicandelas (mcd) is a measure of peak intensity. It's how bright the beam is when looking at it dead on. It's misleading because most beams are brighter in the center and dimmer on the outside. Some LEDs have very high mcd values, but are useless as flashlights because the bright part of the beam is so narrow.

Lumens measures the total light output (flux). Now, if an LED has a flux of one lumen and you shine it on a wall so that the spot is exactly one square meter in area, you get flux density, measured in lumens per square meter. It's a measure of how "bright" a beam really is, when spread over a relatively large area. It's much more informative than mcd.