the image frame, making precision focusing much faster
and more accurate. These AF zones are user-selectable
or can all be activated at the same time for the fastest AF
operation.
Image Stabilization.Image-stabilization lenses op-
tomechanically correct for camera movement and allow
you to shoot handheld with long lenses and relatively
slow shutter speeds. Canon and Nikon, two companies
that currently offer this feature in their lenses, offer a wide
variety of zooms and long focal-length lenses with image
stabilization. If using a zoom, for instance, with a maxi-
mum aperture of f/4, you can still shoot handheld wide
open in subdued light at^1 / 10 or^1 / 15 second and get dra-
matically sharp results. You can also use the light longer
in the day and still shoot with higher-quality ISO 100
and 400 speed settings.
Aperture.
Depth of Field.Telephoto lenses have less depth of field
than shorter lenses. This is why so much attention is paid
to focusing telephotos accurately. The closer you are to
your subject, the less depth of field you will have. When
you are shooting a tight face shot be sure that you have
enough depth of field at your working aperture to hold
the focus on the important planes of the face.
Shooting Aperture.Choosing the working lens aper-
ture is traditionally a function of exposure level, but it is
a matter of preference in many cases. For example, some
photographers prefer f/8 to f/11, even though f/11 af-
fords quite a bit more depth of field than f/8. This is
often because of the relationship between the subject and
the background at various working distances.
Many photographers have strong preferences for cer-
tain lens apertures. Some will shoot wide open, even
though many lenses—even expensive ones—suffer from
spherical aberration at their widest apertures. The wide-
aperture preference arises from a desire to create a very
delicate plane of focus, making the point of focus the
focal point of the composition.
Other photographers, often traditionalists accustomed
to the focus-holding swing and tilt movements of large
format cameras, will opt for a small taking aperture that
holds every plane of the subject in focus. This preferenceTOP—Panning the camera helped blur the background. A slow
shutter speed of^1 / 8 second helped blur the edges of the subject.
The panning motion kept the subject relatively sharp, since the
camera was moving at the same relative speed as the subject. Pho-
tograph by Brian Shindle.
RIGHT—When using a normal lens and a camera-to-subject dis-
tance that creates a full-length portrait, it is fairly easy to capture
the full subject in focus with a relatively wide aperture like f/4 or
f/5.6. This elegant studio portrait was made by Brian Shindle.