Perhaps Brownie cameras aren’t key equipment initially (4)
I believe the answer is:
cake
'perhaps brownie' is the definition.
'cameras aren't key equipment initially' is the wordplay.
'initially' suggests taking the first letters.
The first letters of 'cameras arent key equipment' is 'CAKE'.
(Other definitions for cake that I've seen before include "Eg, gateau" , "Sweet baked pastry" , "Dundee, Madeira, Christmas or birthday?" , "Marie Antoinette's solution to 8" , "Eg, Genoa, Dundee" .)