Artist arrived first with old boy’s partially accurate imaging device (6,7)
I believe the answer is:
camera obscura
'imaging device' is the definition.
(I've seen this before)
'artist arrived first with old boy's partially accurate' is the wordplay.
I cannot quite understand how this works, but
'artist' could be 'ra' (Royal Academician, member of Royal Academy of Arts) and 'ra' is located in the answer.
'arrived' could be 'came' (coming is a kind of arriving) and 'came' is located in the answer.
'first' could be 'a' and 'a' is found in the answer.
'old' could be 'o' (common abbreviation eg in OE for Old English) and 'o' is found in the answer.
'boy's' could be 'bs' (abbreviation used in schools) and 'bs' is located in the answer.
The remaining letters 'cur' is a valid word which might be clued in a way I don't understand.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for camera obscura that I've seen before include "Dark room arranged to project outside objects" , "Dark room, images projected in" , "Early image-projection device" , "Box with lens for projecting image of external view" , "Small building with optical function" .)