EOS Digital for Professionals Brochure

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New 63-zone Metering System
The EOS-1Ds Mark III and EOS-1D Mark III
incorporate a newly-developed, 63-zone metering
sensor linked to the 19 AF points. The metering
sensor is located at the rear of the pentaprism.
The 19 AF points in the Area AF are a highly
favorable match for the metering sensor’s zones.
The metering range is EV 0 to EV 20 (at 73°F/23°C,
50mm f/1.4 lens, ISO 100). The following metering
modes are provided: evaluative, partial, spot, and
center-weighted average. Also, AF point-linked
spot metering is possible with C.Fn I -7-1.
Partial metering reads approximately 8.5%
(EOS-1Ds Mark III)/13.5% (EOS-1D Mark III) of the
viewfinder and spot metering reads approximately
2.4% (EOS-1Ds Mark III)/3.8% (EOS-1D Mark III).
This new Evaluative metering system is based on
the concept for the previous 21-zone and 35-zone
metering systems. With the optimized 63-zone
metering sensor and improved calculations and
processing, more consistent and correct ambient
and flash exposures are obtained with less
influence from the subject. The basic concepts
for the 63-zone evaluative metering are:
1. Metering is weighted on the linked AF point.
2. If there is a very bright object in the picture,
the exposure will be increased.
3. In backlit scenes, the exposure will be increased.
With dark backgrounds, the exposure will be
reduced.
The E-TTL II autoflash algorithm uses the same
newly-developed 63-zone metering sensor.
While based on the previous system which
weighted the metering based on the preflash
reading, the EOS-1Ds Mark III and EOS-1D Mark III
have been further improved to obtain consistent
flash exposures. The major improvements are:
1. Correct flash exposures are obtained even
with off-center subjects.
2. The incorporation of lens distance information
has been optimized to obtain more accurate
flash exposures even with highly reflective
backgrounds.
* C.Fn I -7-1 enables AF point-linked spot metering.
Evaluative/Center-weighted
average metering
Partial metering Spot metering
Built to Perform: Durable,
Rugged, Precise
New 1-Series Body
Both EOS-1Ds Mark III and EOS-1D Mark III retain
and refine the beautiful curved surfaces and
superb basic layout of the EOS-1 series. Ease of
operation and holding comfort have been improved
appreciably, as have ease of operation with
accessories. The cameras are designed to be easier
to understand and more reassuring. The massive
strength of its magnesium alloy body and chassis,
combined with complete environmental sealing,
means that the cameras stand with its forebears
as an instrument worthy of the photographers
who risk their lives daily to take pictures.
All Magnesium-alloy, Including Mirror
Box and Chassis
Because of its lightweight and strength, magne-
sium alloy is used for the top, front, and rear
covers as well as for the memory card slot covers.
The chassis and mirror box are also made of
magnesium alloy to make the body very strong,
rigid, and light. The magnesium alloy also works
as an electromagnetic shield. It is highly
durable, allowing minimal wear even under
harsh conditions.
Design Sketches for the EOS-1D Mark III.
Entirely New High-precision AF System
The new autofocus system of the EOS-1Ds Mark III
and EOS-1D Mark III represent a complete
reconsideration of professional autofocus.
In addition to a new sensor chip, sophisticated
new manufacturing technologies have made it
possible to reconfigure the concave submirror
and the very clever secondary image formation
lens. The result is greater sensitivity, easier
and more logical navigation, higher precision
and significantly better real-world performance.
In the previous 45-point AF system used by such
cameras as the EOS-1v, EOS-1D, EOS-1Ds, EOS-1D
Mark II, EOS-1Ds Mark II and EOS-1D Mark II N,
there were seven cross-type, high-precision
sensors grouped around the center of the frame.
Any of the 45 points could be selected by navi-
gating around the frame.
This was the configuration of the previous 45-
point AF array:
Here is the new AF point layout:
Note that the 19 high-precision, cross-type points
are no longer clustered solely in the center of the
frame. The 26 additional Assist AF points are
horizontal-line sensitive at f/5.6, are not user
selectable, but can be added to a manually-chosen
point to expand its size, and are also used in
Automatic AF point selection mode.
Speed and Predictive-AF Performance
The EOS-1Ds Mark III and EOS-1D Mark III feature
higher precision AF with the 19 user-selectable,
high-precision cross-type AF points and improved
low-light AF performance. Also, to attain AI Servo AF
with the EOS-1D Mark III for 10 fps, the focus
computing is faster and an AF adjustment option
function is provided. The AF sensor, AF computation
method, and AF-related electronic circuitry have
been newly designed for the EOS-1Ds Mark III
and EOS-1D Mark III. This robust new AF system
provides even greater consistency in high-speed
sequences when tracking moving subjects. Even
at its top speed of 10 fps, the EOS-1D Mark III is
less likely than before to have the occasional
soft frame in an AI Servo AF sequence.
Separate CPU for AF
One important difference between the EOS-1D
series and other EOS bodies is that a totally
separate CPU is used strictly for AF processing.
(In other EOS bodies, one main processor handles
primary camera tasks as well as AF processing.)
To attain 10 fps with AI Servo AF (EOS-1D Mark III),
the AF CPU and camera CPU are both the latest
microcomputers (AF CPU: 48 MHz, 32-bit RISC;
Camera CPU: 40 MHz, 32-bit RISC).
The 19 cross-type AF points take advantage of
the following technologies:
• With finer processing steps, the peripheral
circuit could be made smaller and the f/2.8
AF sensor area could be expanded.
• The secondary image-forming lens (see dia-
gram) is molded glass. By incorporating a
newly-developed aspherical surface on the
lens, the focusing area of the f/2.8 light flux
could be expanded.
Each of the 19 cross-type AF points uses a high-
precision horizontal component, with about 3x
the focusing precision of the vertical component.
The benefit is that AF accuracy at the sensor is
enhanced when the photographer needs it most
—shooting with fast lenses, at wide apertures.
This means that on the actual AF sensor, the
horizontal line pairs are significantly farther
apart —and thus require a lens with a maximum
aperture of f/2.8 or faster in order to operate.
At the center AF point, the high-precision horizon-
tal line sensor works with lenses f/4 or faster. In
other words, with fast lenses, two benefits are
realized: added precision, and simultaneous
vertical and horizontal coverage—ideal for
focusing on subjects with little detail. When
lenses with slower maximum apertures are
used, only the vertical AF line sensor is active
at each AF point.
Improvements to the EOS-1Ds Mark III and
EOS-1D Mark III’s AF sensor give even greater
light-gathering efficiency (for both the horizontal
and vertical line sensors), and greater low-light
AF sensitivity. In addition, the camera’s ability
to latch onto subjects with little detail is
improved. Not only is the AF sensor new, but the
entire AF optical system is also newly designed,
including the vital secondary image-forming lens.
Lenses (or lens + extender combinations) with
maximum apertures as slow as f/5.6 can be used
with AF at all focusing points. At the center AF
point only, the camera can focus with a lens +
extender with a maximum effective aperture as
slow as f/8 (using the vertical line sensor only).
The remaining 26 AF points are “Assist Points.”
Each has a single-line vertical sensor, and these
points will focus with lenses having maximum
apertures f/5.6 or faster.
With the EOS-1Ds Mark III and EOS-1D Mark III, the
size of a user-selected AF point can be expanded
(via Custom Function III-8) regardless of whether
the camera is in One-Shot AF mode or AI Servo AF
mode. As noted previously, the AF Assist Points are
also used when the camera
picks the AF point(s) in
Automatic AF point selec-
tion mode.
For low-light focusing, the both cameras are much
more sensitive than previous models. The
CMOS AF sensor’s pixel sensitivity has been
improved, thanks to improved pixel characteris-
tics, an improved pixel fill factor due to finer
semiconductor manufacturing processes, and
optimized pixel size. As a result, the EOS-1Ds
Mark III and EOS-1D Mark III’s AF sensitivity
have been improved to EV -1 through EV 18 (at
73°F/23°C, ISO 100).
: f/5.6 sensors
: f/2.8 sensors
(Center AF point is f/4)
AF Sensor
Sensor horizontal-line
sensitive at f/5.6
Sensor vertical-line
sensitive at f/2.8
Sensor vertical-line
sensitive at f/2.8
Sensor horizontal-line
sensitive at f/5.6
Prime lens
Subject
Focusing plane
(Image plane)
Secondary
image-forming lens
CMOS area sensor
AF Focusing Principle
Actual AF Point Field of View
6.6
7.50
4.5
3.00
2.25
4.00
2.00
: f/5.6 sensors
: f/2.8 sensors
(Center AF point is f/4)
AF Sensor Configuration
EOS-1Ds Mark III & EOS-1D Mark III TECHNOLOGY
EOS-1D Mark III Magnesium-alloy Body