Grope about for study referring to particular lens type (7)
I believe the answer is:
fisheye
'referring to particular lens type' is the definition.
I can't tell whether this definition defines the answer.
'grope about for study' is the wordplay.
'grope about' becomes 'fish' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'for' means one lot of letters go next to another.
'study' becomes 'eye' (both can mean to examine).
'fish'+'eye'='FISHEYE'
Can you help me to learn more?
(Other definitions for fisheye that I've seen before include "Kind of lens" , "Very wide-angle lens" .)