Af And New Autofocus Sensor - Canon EOS 40D White Paper

AF and New Autofocus
Sensor
The [Sensor cleaning] menu is basically the same as the one in the EOS-1D Mark III.
However, there are slight differences such as the shutter operation sequence for [Clean
now]. For the EOS-1D Mark III, it is: Cleaning operation -> Shutter cocking -> Cleaning
operation -> Shutter cocking -> Cleaning operation. In the EOS 40D, it is: Cleaning opera-
tion -> Shutter release -> Cleaning operation.
Unit Construction Diagram
Fig. 41 Unit construction diagram
Fig. 41 Unit construction diagram
Sealing material
Sealing material
Piezoelectric
element
Piezoelectric
element
The option of manual sensor cleaning by raising the mirror and using a blower to
remove dust is the same as other EOS Digital SLR cameras.
A newly-developed AF sensor with 9 cross- type AF points
greatly boosts AF performance, improving both AF detection
precision and extreme-defocus subject detection capability.
AF sensitivity is now EV -0.5 to EV 18. All AF points work as
cross-type points at f/5.6 or better. Both vertical- and hori-
zontal-line sensitive focus detection thus works with any AF point for stable focusing.
High-precision AF is attained with fewer AF failures with hard-to-focus subjects. Also, with
the sensor pitch reduced from 16µm to 14.4µm, detection performance is more accurate.
Sensor Configuration
Fig. 43 Sensor configuration
Cross-type sensor at f/2.8
Two-line sensors
in zigzag pattern
Focusing sensors
for extreme defocus
In sum, the newly-developed AF sensor has appreciably higher performance than the
EOS 30D's AF sensor.
III. PERFORMANCE
Low-pass filter -2
CMOS sensor
Low-pass filter -2
Phaser layer
CMOS sensor
Infrared-absorption glass
Phaser layer
Infrared-absorption glass
Low-pass filter -1
Support material
Low-pass filter -1
Support material
AF Points
Self Cleaning Sensor Unit
Photo 9 Self Cleaning Sensor Unit
Photo 9 Self Cleaning Sensor Unit
AF Sensor
AF Sensor Arrangement
Sensor with F2.8 Support
Sensor with F5.6 Support
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