Something indistinct posh sort of camera conceals (4)
I believe the answer is:
slur
'something indistinct' is the definition.
I can't judge whether this definition defines the answer.
'posh sort of camera conceals' is the wordplay.
'posh' becomes 'u' (abbreviation for upper-class - opposite to non-U).
'sort of camera' becomes 'slr' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'conceals' indicates putting letters inside.
'u' going inside 'slr' is 'SLUR'.
Can you help me to learn more?
(Other definitions for slur that I've seen before include "Slight - mark on music" , "Speak as drunk perhaps" , "Slight, insult" , "making indistinct sound" , "Pronounce indistinctly or cast abuse on reputation" .)