Reference Guide

6
Other
Superior
Features
,
~(
Metering
Systems
The EOS-l's four metering modes
are quickly selected
by
using the main
electronic input dial.
1.
Fine
spot
metering
The most selective
of
the metering
modes, fine spot metering reads only
the light within the smaller circle (5mm
dia.) and thus limits the input value to
2.3070
of
the screen surface, allowing
very precise readings
of
selected parts
of
a photographic composition.
Metering
is
more precise than that
of
competitive cameras because the
spot metering sensor
is
located on the
AF
sensor.
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2.
Partial
metering
The partial metering mode limits
selectivity to the area within the outer
(8mm dia.) circle in the viewfinder,
approximately 5.8%
of
the viewfinder
screen.
It
can be used effectively when
there
is
a strong light contrast between
the main subject and the rest
of
the
scene, such
as
photographs with a
particularly light or particularly dark
background.
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3.
Evaluative
Metering
The six-zone evaluative metering
mode provides exceptionally precise
metering under difficult photographic
conditions, making it easy to handle
'backlit subjects. In this mode, light
is
measured separately in
six
zones.
Ambient light, subject size and subject
pattern are input and "evaluated"
by
a microprocessor using a highly
complex algorithm that determines the
correct exposure.
4.
Center-weighted
Average
Metering
By
increasing the value
of
the light
in the center
of
framed area - the
place where the main elements are
most likely to be - more selective
metering can be accomplished under
conventional lighting conditions.
Custom Function
No.8
replaces
the default evaluative metering mode
with center-weighted average metering.
Automatic
Exposure
A complete selection
of
AE choices
provides the kind
of
operating flexibili-
ty the busy photographer needs. The
main electronic input dial makes
shifting AE modes
easy.
1.
Shutter-priority
AE
The photographer selects the
shutter speed and the camera chooses
the correct aperture value for existing
conditions. Shutter speeds can be set in
I/ 3-step increments, ranging from
30
seconds to 1/ 8000 second.
Tv
D
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)
2.
Aperture-priority
AE
The photographer selects the
aperture value and the camera sets the
correct shutter speed.
As
with shutter
speeds, aperture values can be set in
1 / 3-step increments that are adjustable
to I-step
by
Custom Function
No.6.
Av
D
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)
3.
Depth-ol-Field
AE
The photographer focuses on the
nearest element that
is
to be in focus,
then to the farthest element, locking
these two settings in memory. The
camera then automatically selects the
correct
AF
distance (about 7:
10
of
the
distance between nearest point and
farthest), the aperture required to keep
everything between the two points in
focus, and the correct shutter speed for
lighting conditions.
DEP
D
[
)
4.
Intelligent
Program
AE
This mode calculates both shutter
speed and aperture value
by
taking into
consideration the focal length
of
the
lens being used, which
is
input auto-
matically to the main microprocessor
from the lens microprocessor
as
soon
as
the lens
is
installed. Automatically
calculating the minimum possible
shutter speed for the lens in use
provides reasonable protection against
camera-shake. With zoom lenses,
information
is
transferred simulta-
neously for any focal length selected,
and the program
is
adjusted to match
that focal length. Program shift
is
possible in 1 EV steps.