About: http://webisa.webdatacommons.org/171977184

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	There is a lot of sense in using a card or other flat object to shade the lens, in that you can observe exactly where you need to cast the shadow by simply looking at the lens.
http://www.w3.org/ns/prov#wasQuotedFrom	largeformatphotography.info