Have control over photography session? (4,3,5)
I believe the answer is:
call the shots
'have control' is the definition.
(I've seen this before)
'over photography session?' is the wordplay.
I cannot really understand how this works, but
'over' could be 'all' (synonyms) and 'all' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for call the shots that I've seen before include "Exercise authority" , "Be in charge" , "Take the lead" , "Be in command" , "Film director has to" .)