18
Part I
Navigating and Setting Up the EOS 50D
Focusing distance range selection
switch. This switch limits the range
that the lens uses when seeking
focus. For example, if you choose
the 2.5m to infi nity focusing dis-
tance option on the EF 70-200mm,
f/2.8L IS USM lens, then the lens
does not seek focus at 2.5m and
closer. Choosing the appropriate
focusing range speeds up autofo-
cus speed. The focusing distance
range options vary by lens.
Image stabilizer switch. This
switch turns on or off optical image
stabilization. Optical Image
Stabilization (IS) corrects vibrations
at any angle or at only right angles
when handholding the camera and
lens.
Image stabilizer mode switch. On
some telephoto lenses, this switch
enables image stabilization for
standard shooting and for stabiliza-
tion when you're panning with the
subject movement at right angles
to the camera.
Focusing ring. Turning the focusing
ring enables manual focusing or
focus tweaking at any time even if
you're using autofocusing. If the
lens switch is set to MF, turn this
ring to focus on the subject.
Zoom ring. Turning this ring zooms
the lens to the focal length marked
on the ring. On some older lenses
such as the EF 100-400mm f/4.5-
5.6L IS USM lens, zooming is
accomplished by fi rst releasing a
zoom ring, and then pushing or
pulling the lens to zoom out or in.
Distance scale and infi nity com-
pensation mark. The distance
scale shows the lens's minimum
focusing distance through infi nity.
The scale includes an infi nity com-
pensation mark that can be used to
compensate for shifting the infi nity
focus point that results from tem-
perature changes.
Viewfi nder display
The eye-level pentaprism viewfi nder shows
you 95 percent of the scene that the camera
captures. The viewfi nder includes nine AF
points superimposed on the focusing screen,
as well as key exposure and camera setting
information.
Looking through the viewfi nder during shoot-
ing allows you to verify that camera settings
are as you want, or to alert you if they need
to be changed. In addition, you are alerted
when any exposure element you've chosen
is beyond the exposure capability of the light
in the scene. For example, if you see the
aperture blinking in the viewfi nder, it means
that the image will be underexposed (too
dark) and that you need to set a slower shut-
ter speed or a higher ISO. Or if you were
using Exposure Compensation for previous
shots and don't need it for the current shot,
the viewfi nder is a reminder to reset the
compensation.
The following diagram shows the view-
fi nder information and what each element
represents.
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