Also, the second-generation, on-chip noise removalcircuit and a
newly-developed noise reduction technologycombine to remove
noise effectively. To achieve even lessnoise, the EOS-1Ds MarkIII
hasa new output amp that attains both high speed and low noise.
Low noise isalso achieved with an improved manufacturing
process, optimized pixelamp, and optimized reading circuit.
Thanksto optimized photo diode construction and finer process-
ing, the photo diode can stillaccumulate enough light to function
exceptionallywell. At low ISO speeds, the dynamic range is about
the same asthat of the EOS-1Ds Mark II.
Aswith the EOS-1D Mark III, single-line, 8-channel parallel reading
isemployed. With a low-noise, high-speed output amp, a continu-
ousshooting speed of approximately 5 fps is attained, even with
approximately21.1 megapixels with which to contend.
The infrared, low-passhybrid filter in front of the sensor consists
ofan infrared-absorption glass (including multiple coatings to
reflectultraviolet and infrared rays) and low-pass filter (phase
plate sandwiched bytwo single-crystal plates). Other than opti-
mization for the full-frame CMOSsensor, the specifications are the
same asfor the EOS-1D Mark III.
The state-of-the-artAF sensor in the EOS-1Ds Mark III is shared with the EOS-1D Mark III.
The AI SERVO AFalgorithm has been optimized to match the continuous shooting speed
ofthe EOS-1Ds Mark III, approximately 5 fps. Also, due to the full-frame CMOS sensor,
the AreaAFcoverage with respect to the viewfinder is slightlysmaller than with the EOS-1D
MarkIII. The AF speed and predictive AF performance are the
same aswith the EOS-1D Mark III. All other AF-related specifi-
cationsnot mentioned here are also the same as the best-in-
classEOS-1D Mark III.
IV. DISCUSSION OFNEW AND IMPROVED FEATURES 12
Autofocus
Time
Low-pass filter
(Separates image in vertical direction)
Low-pass filter
(Separates image in horizontal direction)
Phaser layer
(Converts linear polarized
light into circular polarized light)
CMOS
sensor
Dichroic mirror
(Reflects infrared rays)
Infrared-absorbing glass
LPFConstruction
Diagram of8-channel
SignalReading
:f/5.6 sensors
:f/2.8 sensors (Center AF point is f/4)
:Cross-type AF points : Assist points (Not user-selectable)
6.6
7.50
4.5
3.00
2.25
4.00 2.00
AFSensor Configuration
AF Sensor