About: http://webisa.webdatacommons.org/48960925

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	A spirit level laid on the focusing screen is a good idea because that is your datum point for much of the time, but the rest of the camera can point in any direction when it comes out of the bag.
http://www.w3.org/ns/prov#wasQuotedFrom	apug.org