== Radiance Article == 

 "The last edit presumes radiance is conserved, which is not always true." 

 I see your point.  However, I am trying to rationalize the definition, which says L is the observed or measured radiance and  is the radiant flux per steradian.  It appears that the definition is an implicit correspondence between an emitted radiance and a measured radiance.  Therefore, anytime the definition is applied there is an implicit emission surface and detector surface.  Granted, these surfaces may be infinitely close so that there is no opportunity for scattering and other losses.  I understand that the way I originally wrote it implies something that is not always correct.  However, I wanted to clarify why L and  have the same units but differ by a 1 over cosine term.  The answer is that they are talking about solid angles defined from different perspectives and areas of different surface.  Any advice on how to rectify this confusion in a rigorous sense.