In the judge's chambers, to change a mac takes a long time (6)
I believe the answer is:
camera
'in the judge's chambers' is the definition.
I can't judge whether this defines the answer.
'change a mac takes a long time' is the wordplay.
'change' indicates anagramming the letters.
'takes' says to put letters next to each other.
'a long time' becomes 'era' (a long period of time).
'mac' with letters rearranged gives 'cam'.
'cam'+'era'='CAMERA'
'to' acts as a link.
Can you help me to learn more?
(Other definitions for camera that I've seen before include "Brownie possibly" , "Common image recording device" , "One never lies" , "Snapper's kit" , "Picture producer" .)