Canon EOS 20D Service Manual page 74

Technical Information
(2) Low ISO speeds
More minute processing, the
elimination of transistors in the
pixels, and optimized photo diode
construction enable the photo diode
to accumulate enough light. The
dynamic range at low ISO speeds is
therefore improved. Thus, even
though the camera's pixel size of
6.4. × 6.4 mm is smaller than the
EOS 10D's pixel size, the same ISO
100 speed as the EOS 10D can be
attained.
3) Low noise
Fixed-pattern noise and random noise which used to be a problem with CMOS
sensors have been effectively suppressed as EOS digital technology advanced.
Today, Canon's ultra low-noise CMOS sensor can even photograph the heavens
in the night sky with very low noise.
The EOS 20D suppresses noise even further with its CMOS sensor. The
random noise generated by the pixel's amp is reduced thanks to the improved
device. And the second-generation, on-chip, noise-filtering circuit effectively
eliminates random noise and fixed-pattern noise.
4) High-speed, 4-channel reading
While based on the EOS 10D's 2-channel reading, more channels and faster
speed have been incorporated in the EOS 20D. With one-line and 4-channel
reading and a low-noise, high-speed output amp, high-speed signal reading
enabling a continuous shooting speed of 5 shots/sec. is attained.
4-channel reading
Fig. 003 Four-channel reading
Table 002 CMOS Sensor Specifications
Camera Pixel Size
6.4 × 6.4µm
EOS 20D
7.4 × 7.4µm
EOS 10D
8.2 × 8.2µm
EOS-1D Mark II
8.8 × 8.8µm
EOS-1Ds
11.5 × 11.5µm
EOS-1D
2-channel reading
2
ISO Speed
100 - 1600 • 3200
100 - 1600 • 3200
50 • 100 - 1600 • 3200
50 • 100 - 1250
100 • 200 - 1600 • 3200