Likeness of even film era (5)
I believe the answer is:
image
'likeness' is the definition.
(I've seen this before)
'even film era' is the wordplay.
'even' indicates alternate letters (letters in even-numbered positions are used).
'era' becomes 'age' (both can mean a long period of time).
The alternating letters of 'film' are 'im'.
'im'+'age'='IMAGE'
'of' is the link.
(Other definitions for image that I've seen before include "Picture (involving one letter change from 10)" , "Picture; simile" , "Likeness or mental picture" , "Purplish pigment; pool" , "Epitome" .)