For landscape photographers Hyperfocal Distance is a useful tool
for providing maximum depth of field. Primarily used with wide
angle lenses and small apertures, focusing at the hyperfocal point
will provide a depth of field that extends from halfway between
the camera and the focus point out to infinity. For example, if,
for a given f-stop and focal length, the hyperfocal point is six
feet, everything from 3 feet to infinity will appear to be in
focus. This allows for inclusion of a strong foreground in a landscape,
while maintaining focus of the distant scenery.
There is no magic to this. It is simply a matter of optical physics.
For practical use, all you need to know is the formula and you
can calculate the Hyperfocal Distance for any lens/f-stop combination
for any camera. The formula is the square of the focal length divided by
the product of the f-stop times the "circle of confusion." The COC is
the key, as it varies for each film format you encounter. A simple web
search for "Hyperfocal Distance" will take you to a number of pages with in
depth discussions about the physics of this and the various values for the
COC.
To help out when I am in the field, I have created a chart sized
to fit in my camera bags and backpacks. The chart is for various
focal lengths that I use with 35mm cameras. To help out others,
I have made the chart available here. Simply download the file,
open and print it. I would suggest laminating it, so that it holds
up to use. The file is in PDF format, so you will need Adobe Acrobat
Reader to access it. This is available for free from
Adobe Systems.
I have also written a small applet that calculates the Hyperfocal
Distance for any focal length and f-stop combination across a
number of standard film formats.
Hyperfocal Distance Chart:
hyperfocal.pdf