Hyperfocal Distance
| Introduction: | |||
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Hyperfocal distance comes into play generally when dealing with
landscape photography. It is a way to maximize the Depth of Field (DOF) in
your image ensuring that your final image is sharp throughout. The
hyperfocal distance is a function of aperture, focal length, and the Circle
of Confusion (COC). The COC is the largest on-film (sensor) circle that
you can see as a well defined point on an 8 x 10 print from a distance
of 1foot. Anything larger than this point is seen as a circle and
is said to be out of focus. There are several ways to create a larger DOF in an image. You can use a larger F-number (smaller aperture). The problem with this method is that at an aperture of F16 or greater you will lose sharpness in your image due to diffraction. The second method is to use a lens with a shorter focal length. Wide angle lenses have a naturally larger depth of field if we ignore the subject size. (If you use any lens and the subject fills the frame the same way then the DOF will be the same regardless of the lens used. Read here for more info.) The third method is to employ the hyperfocal distance. |
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| Definition: | |||
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The hyperfocal distance is the focus distance which places the maximum
allowable COC at infinity. Everything at half this distance to infinity
will be in focus. (this is because one of the law of optics states that
the depth of field extends 1/3rd in front and 2/3 beyond the point of
focus) Hence focusing at any point
in front of the hyperfocal distance would mean that somewhere in
infinity range of the image there would be an object out of focus (far
mountain peak, tree, cloud etc). What this also means is that if you
focus at infinity, the hyperfocal distance will be the beginning of your
depth of field. Everything in the scene in front of your hyperfocal
distance will be out of focus. The hyperfocal formula is defined as this:  |
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| Landscape Focusing: | |||
In virtually all landscape photography, there is always some foreground
element which guides the eye to the subject in the image. If you focus
at the subject, your run the risk of having this foreground object out of focus.
The DOF will not quite reach your foreground element(s). If you focus at infinity, this makes this even worse. Not only will your foreground be out of focus, but your subject as well.  Focusing on the foreground element will result in objects at the far reaches of the scene to be out of focus such as faraway mountains etc.  The only way to achieve correct focus is to employ the hyperfocal distance. Focusing using the hyperfocal distance will enable you to have your foreground, subject and the most distant features of your landscape image in focus.  |
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| Hyperfocal Usage: | |||
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In the field, it is generally best to carry a table of hyperfocal
distance calculations for a particular lens. These tables can then be
used to figure out the hyperfocal distance for a particular focal length
and aperture. Below are the tables of most common focal lengths for Nikon Digital SLR's,
Canon digital SLR's, and 35mm film cameras, as well a calculator at the
bottom for
computing custom focal lengths. Feel free to print out the tables and
use them. Cheers |
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| Nikon Digital SLR's | Canon 1D/Mark Series | Canon 1Ds/5D Series | 35mm Format Cameras |
