Exposure Control - Canon EOS 7 Service Manual

Part 2: Technical Information
1.4 E
XPOSURE
(1) Metering
1) Metering optics and AE sensor
The EOS ELAN 7 E / EOS 30's metering optics (see Fig. 2-12) are directly behind
the pentaprism toward the top. This is to prevent it from obstructing the Eye
Control optics.
Like the EOS 300/Rebel 2000/EOS Kiss III, the EOS ELAN 7 E / EOS 30 uses a
35-zone SPC as the AE sensor. Also, the 3-zone flash sensor for TTL autoflash
exposure enables the six metering modes listed in 2) below.
For details on the AE sensor, see the EOS 300/ Rebel 2000/EOS Kiss III Service
Manual
2) Metering modes and
metering patterns
The EOS ELAN 7 E /
EOS 30 has the same
metering modes as the
EOS 300/Rebel 2000/
EOS Kiss III:
Evaluative (focusing
point-linked with 35
zones), 2 Partial
metering at center, 3
Centerweighted
averaging metering, 4
Preflash metering, 5
3-zone, off-the-film TTL
flash metering, and 6
TTL/A-TTL autoflash.
The metering algorithm is also the same as the EOS 300/Rebel 2000/EOS Kiss
III's. The 35 metering zones are divided into three groups: a (main subject
metering area), b (intermediate metering area), and c (peripheral metering area).
The three metering areas are compared to calculate and obtain the correct
exposure. Because the above metering algorithm is used, the metering patterns
are almost the same as the EOS 300/Rebel 2000/EOS Kiss III's. For details, see
the EOS 300/Rebel 2000/EOS Kiss III Service Manual
C
ONTROL
[Evaluative metering]
Left focusing point
1
Main subject metering area
2-10
Center focusing point
Intermediate metering area
[Centerweighted averaging metering]
[Partial metering at center]
*With C.Fn-8-0.
Fig. 2-14 Metering Areas
Bottom focusing point
Peripheral metering area Non-metering area