Calculating distance between lux meter and light source

[san-yas]

I am currently performing some experiments to calculate the distance between a light source and a lux meter where the light source points directly towards the lux meter.
Is it possible to calculate the exact distance between the light source and the lux meter given that we have a lux value (through the lux meter) and the luminosity flux (through the information given by the light source manufacturer)? or is the inverse square law (lux=lm/d^2) subjected to particular conditions?

 

[berkeman]

Welcome to PF.

It seems like the inverse square law should work for this. What have you seen in your experimental data so far?

 

[sophiecentaur]

a light source

If the source has a significant area then ISL will stop working close up. Also, if the source is a laser, you will have a problem because the effective position of the source can be may metres behind the front (multiple mirror images, as with an infinity mirror) and the r in 1/r² would need to be corrected for. ISL is fine for stars and planets but the Moon and Sun are very much distributed sources.

I would be inclined to do the experiment first and find what distance the ISL begins to work for.