How Digital Photography Works

(^54) PART 2 HOW DIGITAL CAMERAS CAPTURE IMAGES
How Digital Lenses Manipulate Space
Telephoto and wide-angle lenses do more than change the size of your subject or the breadth of your image. They also change the relative
sizes and relationships among individual objects in the photograph. A common misunderstanding is that lenses with different focal lengths
change the perspective in photographs. For example, look at the three cubes shown here and guess which are representative of objects
shot with a wide-angle, normal, or telephoto lens.
You probably guessed immediately that that was a trick question. The answer is that all the photos
were shot with a digital camera using the same focal length. To be precise, they are all part of the
same photo, as seen below.
What actually changes the perspec-
tive is the distance from the camera
to the subject being photographed.
The box nearest the camera was the
most distorted; the box farthest from
the camera appears to be more like
a regular cube. What causes the
distortion is perspective. Another
of life’s visual illusions that we’ve
come to accept as reality, perspec-
tive compresses space in proportion
to the distance from the observer to
what’s being observed. (If the
objects being observed were small
enough originally and are
extremely far away, they disappear
entirely at the appropriately named
vanishing point, sort of an opti-
cal black hole except that it doesn’t
actually exist and objects don’t
really vanish.)
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