Camera accessory left in zoo toilet (4,4)
I believe the answer is:
zoom lens
'camera accessory' is the definition.
(I've seen this before)
'left in zoo toilet' is the wordplay.
'left' becomes 'l' (common abbreviation).
'in' indicates putting letters inside.
'toilet' becomes 'mens' (men's is a kind of toilet).
'zoo'+'mens'='zoomens'
'l' going within 'zoomens' is 'ZOOM LENS'.
(Other definitions for zoom lens that I've seen before include "Camera attachment" , "Camera accessory" , "This'll bring you closer still" , "Camera feature" .)