Tom Hogan's formula for hyperfocal distance
(Nikon Field Guid, p98) is stated as
(F X F)/(f x F x .001)
Where F is focal length and f is the aperture.
A simplification of this formula (allowing for
some round-off error which builds up below 35mm)is
H = 3.3 x F/f
Where:
H = hyperfocal distance in feet
F = Focal length of the lens in mm
f = aperture (nondimensional)
If you apply these figures to a 80mm lens at f8,
for example, you will get an hyperfocal distance of
3.3 x 80/8 = 33.3 feet
and a 100mm at f-16 is
3.3 x 100/16 = 21 feet
Another simplification for field work is that at
f-16 the distance from 1/2 the hyperfocal distance
to infinity is "in focus". So, for landscapes, if
you settle for f-16 as a standard aperture, all you
need remember for both hyperfocal distance and DOF
(near focus point to infinity) is
H = 0.3 x F !!! (H in feet, F in mm)
OK, I'm braced for the flames =;)
....patrick
