Closely examine small container for storing film (4)
I believe the answer is:
scan
'closely examine' is the definition.
(to scan is to examine in detail)
'small container for storing film' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'container for storing film' becomes 'can' (container for filmstrips).
's'+'can'='SCAN'
(Other definitions for scan that I've seen before include "Examine closely to analyse metrically" , "Examine data" , "Take a quick look" , "Look over cursorily" , "Browse or skin over, say book" .)