candelas to lumens conversion?

Just wondering if anyone has a simple conversion between candelas and lumens. Reason is that I'd like to compare the amount of light coming from a super-bright LED to that from an incandescent bulb.

I know that lumens are a measure of total luminous flux, and that candelas tell you the flux in the beam, so I think I need to integrate candelas over the solid angle specified for the LED beam pattern...or do I?

Any thoughts?

Thanks,

vince

You're real close! Here's the basics.

**IF** the light is putting out one candela over one steradian (solid angle where the area equals the square of the radius--there are 4*pi of these in a sphere) then the light is a one lumen light.

**IF** the light is putting out equal light in all directions and the light meter is reading one candela then it is a 4*pi lumen lamp.

Lumen outputs of complex lighting devices are measured in large integrating spheres.

Without knowing LOTS about the beam pattern, you cannot do the conversion.

Cheers,

Richard

There are a lot of companies advertising LEDs with very very high Candle output, but most of these achieve this by making the beam VERY narrow

Personally, I think Lumens is a better way to measure light output