Light Meter - measure luminosity in lux, fc, lumen App Reviews

I really like the way this tool works. They say That if you design something well, you dont need to write a book about it. This tool may not be NIST traceable but if you have a nice modern iPhone like my 6 plus, it is truly great IMO. Very useful to me as a machine vision guy.

This app was to check lighting but found the db meter helpful as well