People involved in cameras (9)
I believe the answer is:
americans
'people' is the definition.
(I know that Americans is a nationality)
'involved in cameras' is the wordplay.
'involved' indicates anagramming the letters (involved can mean confusing or complex).
'in'+'cameras'='incameras'
'incameras' is an anagram of 'AMERICANS'.
(Other definitions for americans that I've seen before include "across the pond?" , "Yanks" , "Rains came (anag.)" , "New Yorkers, e.g." .)