Moving camera with metal casing fell over (4,1,7)
I believe the answer is:
came a cropper
'moving camera with metal casing fell over' is the definition.
I know nothing about this answer so I can't judge whether this works.
'moving camera with metal casing fell over' is the wordplay.
'moving' is an anagram indicator.
'with metal casing fell' becomes 'copper' (I can't explain this - if you can you should believe this answer much more).
'over' is an insertion indicator.
'camera' is an anagram of 'ameacr'.
'ameacr' put into 'copper' is 'CAME A CROPPER'.
Can you help me to learn more?
(Another definition for came a cropper that I've seen is " fell off?".)