About: http://webisa.webdatacommons.org/225475207

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	The most difficult thing was that with my 50mm lens, which has a short minimum focus distance of about 11 inches anyway, the minimum focus distance with the tubes was a couple inches, tops!
http://www.w3.org/ns/prov#wasQuotedFrom	blogspot.com