Shutter of Leica only opening to one diameter? Yes, as reported initially (6)
I believe the answer is:
eyelid
'shutter' is the definition.
(I have seen 'Facial shutter' mean 'eyelid' so perhaps 'shutter' could also mean 'eyelid')
'diameter? yes as reported initially' is the wordplay.
'diameter?' becomes 'lid' (I am not sure about this - if you are sure you should believe this answer much more).
'yes' becomes 'ay'.
'as reported' indicates a 'sounds like' (homophone) clue.
'initially' says to put letters next to each other (some letters go before others).
'ay' sounds like 'eye'.
'lid' after 'eye' is 'EYELID'.
'of leica only opening to one' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for eyelid that I've seen before include "Optical membrane" , "Natural optic protector" , "Fold of skin on the face" , "Covering for organ of sight" , "Protective cover" .)