Mathematical Phenomenon
The hyperfocal distance is a curious property: While a lens focused at H will hold a depth of field from H/2 to infinity, if the lens is focused to H/2, the depth of field will extend from H/3 to H; if the lens is then focused to H/3, the depth of field will extend from H/4 to H/2. This continues on through all successive 1/x values of the hyperfocal distance.
Piper (1901) 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.
The figure on the right illustrates this phenomenon.
Read more about this topic: Hyperfocal Distance
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