Understanding Exposure Chapter 3 Controlling exposure
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Click to explore how
exposure determines
how light or dark an
image is.
The importance of Exposure...
Photography begins with an exposure when you press the camera’s shutter
button. The shutter opens and light reflected from the scene enters through
the lens and strikes the image sensor to create the image. By controlling
how much light reaches the sensor you control how light or dark the picture
is—one of the most important aspects of photography. When a scene has both
very light and very dark areas, getting the perfect exposure is a lot like park-
ing a large car in a small garage—there isn’t a great deal of room for error.
Your goal is to retain details in both the darkest and lightest areas so pure
white is used only for spectral highlights such as reflections, and pure black is
used only for those few areas of the scene that are black with no details.In this scene there
are details in all of the
whites that give them
texture and form. The
small white square has
been added to give you
a reference to what
pure white would look
like.
In this scene there are
details in the darkest
shadows. The small
black square has been
added to give you a
reference to what pure
black would look like.
One of the things that
makes an Ansel Adams
print so stunning was
his ability to hold details
in both the brightest
and darkest parts of
a scene. To do this
with film he developed
the Zone System
that guided him in
adjusting exposure and
development times for
the best results. Today
the adjustments are
made with a photo-
editing program.