Editing Hyperfocal distance (section)

== Consecutive depths of field ==
The hyperfocal distance has a curious property: while a lens focused at {{mvar|H}} will hold a depth of field from {{math|''H''/2}} to infinity, if the lens is focused to {{math|''H''/2}}, the depth of field will extend from {{math|''H''/3}} to {{mvar|H}}; if the lens is then focused to {{math|''H''/3}}, the depth of field will extend from {{math|''H''/4}} to {{math|''H''/2}}.  This continues on through all successive neighboring terms in the [[harmonic series (mathematics)|harmonic series]] ({{math|1/''x''}}) values of the hyperfocal distance. That is, focusing at {{math|''H''/''n''}} will cause the depth of field to extend from {{math|''H''/(''n'' + 1)}} to {{math|''H''/(''n'' &minus; 1)}}.

C. Welborne Piper calls this phenomenon "consecutive depths of field" and shows how to test the idea easily.  This is also among the earliest of publications to use the word ''hyperfocal''.<ref name="Piper1901" />