Do all LEDs have the same optical power vs current curve?
(NOTE: Thanks to some guidance and patience from some patons of EESE, not to mention my naieve/unfortunate/inaccurate word choice in the original version of this question, I have been able to condense it down to just a single sentence. As such, it takes away the context under which the two answers were given. For example, the answers mention "an indicator LED" and a situation where I "replace an old (indicator) LED with a modern one". Rather than rewrite this question from square one so as to maintain context and express a coherent question (assuming I could even do this), I have decided to take the advice given to me and ask the question that best solves my problem. But since I didn't want to ignore the help I had getting what I came here for, I thought I should write this note. As far as context (for the theoretical reader who might be wondering), I realized that this now-viable question doesn't supress the context , it has found it a nice home: in the edit history.)