Reference Guide

Two Microprocessors
The EOS-l emplo ys an information proce ssi ng sys tem
composed
of two microproce ss or s. One is a high-speed
super-microprocessor that
is dedicated to AF operation
only. The other microproc
es sor is in char ge of AE and
sequence control
s. The two m ic roproc es sors can handle
data independently and simultaneousl
y. As a result, overall
ele ctronic operati on is h ig hl y· reliable, and AF operation
speed and accura
cy is obviously superior.
Bl ock Diag ra m of Electronic circuits
Command ba ck
I
iii
I
I
I Dial IC I
'r-
Dedicated flash
Stan dard back
EOS-I body
Direct contacts
Dir
ec t contacts
f----1
V
Metering sensor
I--
I Fl ash co ntrol se nsor J------...
1/0-1
1
DX code
r-
M-J
Moto r dr i ve r 1
hl
,~
~
Mo tor driver 2
I
SW- l
1
I
SW-2
1
Main microprocessor
A
Da ta input
I
..;
~[]E
Main switch
Input dials
~ 7
Selectors &
b utto ns
~
LCD driver
~ Beeper
To a ll units
0
)
\}
~
Display pane l LCD
converter :
. r' 8888
l
l l
Viewfinder
D~8 . BI SO ~
display LCD
I
[i:JA ~i @E~
I Power so ur ce
I
Q.-'~~1~;,::J ;.;. '~:."1.:. · 1:.t l
I
2CR5
I '-'I EL r LED array
1-'
L _______________ _ _
6-zone Evaluative Metering
This new evaluative metering system divides the frame
into
six zones. The EOS system's main microproce ss or uses
an algorithm which evaluates luminance in each
of the si x
sections to determine the correct exposure
by comparing
differences in brightness between the various metered
areas, comparing center to immediate and immediate to
peripheral. This comparison estimates subject size and the
conditions in which the subject is situated, considerations
which are factored-in to make the final exposure deci
si on.
The system also detects variations in subject reflective
luminance
level. When the luminance level is high, it
compensates to obtain high-lighted depiction, and when
the luminance
is low, it compensates to obtain shadow
depiction. Since the camera automatically focuses on the
object to
be photographed, AE is calculated and locked
automatically
as soon as focusing is completed.
Cross BASIS
I Spot metering sensor I
1/0-2
~ ;.
Se lf-lime rLE
~
•
AF microprocessor
M ,-3- ,' Mg-3.2 1 @
Shutter
1
-- - - -
<
> Bidirectional serial data bus
for
data communica tion
EF le ns
Co n tro lI C
L..! AFD / USM EMD I
-r
Pu lse plate
I
~
I,
I.-{ foca l len gth J
f......r Macro in format io n I
I
Lens microprocessor
I
~ FO CUS in g mode AF 1M)
Electronic mount
Power Dr i ve Booster
f-
H
Sw. Lock 1
+ To a ll uni ts
I--
~ Motor driver 31 I
~ Power so ur ce
DC/DC
LR 6xB
converter
M·3
I
f--
...J
11