Editing Hyperfocal distance (section)

===Kingslake 1951===
[[Rudolf Kingslake]] is explicit about the two meanings:<ref name="Kingslake1951" />

{{blockquote|if the camera is focused on a distance {{mvar|s}} equal to 1000 times the diameter of the lens aperture, then the far depth {{math|''D''{{sub|1}}}} becomes infinite.  This critical object distance "{{mvar|h}}" is known as the ''Hyperfocal Distance''.  For a camera focused on this distance, {{math|1=''D''{{sub|1}} = ∞}} and {{math|1=''D''{{sub|2}} = ''h''/2}}, and we see that the range of distances acceptably in focus will run from just half the hyperfocal distance to infinity.  The hyperfocal distance is, therefore, the most desirable distance on which to pre-set the focus of a fixed-focus camera.  It is worth noting, too, that if a camera is focused on {{math|1=''s'' = ∞}}, the closest acceptable object is at {{math|1=''L''{{sub|2}} = ''sh''/(''h'' + ''s'') = ''h''/(''h''/''s'' + 1) = ''h''}} (by equation 21).  This is a second important meaning of the hyperfocal distance.}}

Kingslake uses the simplest formulae for DOF near and far distances, which has the effect of making the two different definitions of hyperfocal distance give identical values.