Hi all, I'm trying to understand the difference between nits, candela, lumen and lux. Just to make sure I've got this right, I'll paste in four concise descriptions for each of the units, and if anyone can alter/adjust them, that would be great. I imagine nothing could be clearer than stating what variables need to be taken into account for each unit. "matters" below means to "take into account" as variables. Also, "object area" could be translated as the 'viewer', or the surface that the light is shining on. Candela/m^2 or Nit ::: light-source-intensity matters Candela ::: light-source-intensity matters AND light-source-size matters Lumen/m^2 or Lux ::: light-source-intensity matters AND light-source-size matters AND light-source-distance-from-object matters Lumen ::: light-source-intensity matters AND light-source-size matters AND light-source-distance-from-object matters AND size-of-object-area matters For the last two, the terms light-source-distance-from-object and size-of-object-area can be combined to form the translation: "angle of the light source's cone". Is everything present and correct?