Reference Guide

The EMD is perfectly matched to the
needs of a professional SLR camera.
Its digitally controlled accuracy
is far more consistent than any
analog mechanical diaphragm can
ever be. Beyond unequaled
reliability and precision, it also
offers simple depth-of-field
preview in all exposure modes,
including those in which the camera
calculates the aperture.
Exclusive Sensors for Improved
Performance
Two other existing EOS system
features made it into the EOS-l:
the 6-zone Evaluative Metering
sensor and the BASIS Autofocus
sensor. Both of these devices,
exclusively designed and
manufactured by Canon for EOS, have
been improved and augmented with
new performance and features that
exceed those of previous EOS
cameras. We'll cover them in more
detail later.
Lens-Integral Dedicated Motors
To complete the round-up of
existing EOS technology used by the
new camera, let's briefly examine
the lens-integral dedicated
focusing motors. Unlike other AF
SLRs, we have placed a focusing
motor in each EF lens, to improve
performance and camera handling
compared to body-integral designs,
and to allow us to match motor
characteristics to individual lens
types.
We use two types of focusing
motors! the Ultrasonic (USM) and
the Arc Form Drive (AFD).
The USM is unique because of its
solid-state design which provides
direct drive with very high torque
and superior start-stop response.
Even during manual focusing, a USM
lens is driven by its focusing
motor. This provides a new
dimension in camera handling,
making it possible to provide both
AF and manual focusing without the
need for mechanically switching
between the two. An added benefit
is silent operation, unavailable in
body-integral AF cameras.
Canon places the USM in a select
group of L-Series professional
lenses, including the new SOmm
f/l.OL and 8Smm f/l.2L.
The AFD is a small arc-shaped motor
which maintains the size and shape
of each lens. It can be
manufactured in many different
sizes to match the needs of each
lens type. It is also less costly
than the USM. Canon has upgraded
the performance of the AFD in its
latest EF lenses, including the EF
20-3Smm f/2.8L and the EF 80-200mm
f/2.8L.
2. EOS-l PROVIDES SIMPLIFIED
OPERATION AND IMPROVED CAMERA
HANDLING.
Quick Control Dial Accelerates
Camera Handling
Without question, the biggest
design breakthrough on the EOS-l is
the new Quick Control Dial located
on the back of the camera. Even
though there has never been a
control quite like it, you'll be
amazed at how comfortable the Quick
Control Dial is from the first time
you pick up the camera.
This alternate input dial
accelerates camera handling by
making full exposure adjustment a
one-hand operation. In manual mode,
you can change the shutter speed
with your index finger while you
adjust the aperture with your
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