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1991-03-27
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Depth of Field 21/3/91
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This programme is designed to calculate and tabulate the
depth of field of any chosen lens, when focussed at a
given distance.
This is particularly important in small scale photography
or studio work, especially when critical definition is required.
When an object in front of a lens is in focus, part of the scene
in front of and behind the object will also appear to be in focus.
The distance between the furthest and nearest points that are in
focus is the depth of field.
Basically the nearer a lens comes to being a pin hole camera
the better the depth of field.
In fact, those parts in front of and behind the focal plane are
not really infocus at all. They just appear to be, because the
human eye cannot distiguish between a sharp point and a very small
circle, (called the circle of confusion).
The depth of field, therefore, depends on the size of the circle
of confusion. (Sharpness in the final photograph also depends on
the viewing distance as well.)
Selecting critical depth of field gives a smaller circle of confusion.
The hyperfocal distance is a special case, especially useful in
maximising depth for, say, a landscape. If the lens is set to the
hyperfocal distance for the given f-number then the depth will extend
from half the focal distance to infinity.
The programme is self evident and needs no further description.
E.F.Lord BSc
Crawley,
21/3/91
END OF README FILE