About: http://webisa.webdatacommons.org/6083187

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	Unfortunately, one of the interesting properties of a practical fish-eye lens is that the entrance pupil is at a changing distance along the optical axis as you vary the angle of the incident ray makes with the axis.
http://www.w3.org/ns/prov#wasQuotedFrom	stackexchange.com