IV. DISCUSSION OFNEW AND IMPROVED FEATURES 14
Viewfinder
The EOS-1DsMark III is compatible with UDMA (Ultra Direct Memory Access), a new CF
card specification (CompactFlash SpecificationsRevision 4.0) enabling high-speed writ-
ing to the CFcard. With a UDMA CF card, the high-speed data transfer is about twice as
fastas the EOS-1D Mark III (about 3 times as fast as the EOS-1DsMark II). Although the
EOS-1DsMark III has twice as many pixels as the EOS-1D MarkIII, the writing speed per
file isabout the same as the EOS-1D Mark III, which is quite amazing.
The camera iscompatible with SD memory cards including SDHC (SD High-Capacity)
cards. The writing speed with SD cardsis the same as that of the EOS-1D MarkIII.
Large, brightviewfinders are an inherent advantage of full-frame sensor DSLR cameras.
The viewfinder ofthe EOS-1Ds Mark III incorporates a totally redesigned pentaprism and
refined eyepiece opticsto make the viewfinder performance of the EOS-1Ds Mark III the
best in its class. Remarkably, the viewfinder providesthe highest magnifi cation and wide st
coveragein the history of EOS-1 series cameras, including film models, approximately
0.76xand 35°. This is a substantial improvement over the EOS-1Ds Mark II. The new
finder also correctsthe distortion in EOS-1Ds series cam-
erasto make the large viewfinder look more natural. The
100% viewfinder coverage, approximately20mm eye-
point, -3 to +1 dptdioptric adjustment range, and eye-
piece shutter are the same asthe EOS-1D Mark III’s. It is
nowan even greater pleasure to lookthrough the finder
and the pointof focus is much easier to find and follow.
Aswith the EOS-1Ds Mark II, glass with a high refrac-
tive indexis used for high performance. To match the
higher viewfinder magnification (wider viewfinder cov-
erage), the pentaprism and SI prism have been made
larger, necessitating a change in the top
exterior cover ofthe camera’s body.
The lenstype and glass selection have
been changed to make the eyepiece
lenslarger. By having 4-lens elements
in 4 groupsfor the eyepiece optics,
flare issuppressed.
EOS-1D Mark III coverage
EOS-1Ds Mark II coverage
EOS-1Ds Mark III coverage
Viewfinder Coverage Comparison
Magnification [Approx. X] (Viewing angle [°])
Item 1D Mark III1Ds Mark III 1Ds Mark II 5D
Coverage [Approx. %] 100 100 96 100
0.76(35.0) 0.76 (28.3)0.71 (32)0.70(31.9)
Eye point Approx. 20 mm
Dioptric adjustment -3 - +1 dpt
Major Viewfinder Specifications
Pentaprism
Backlight lens
SI-LED
Metering lens
Condenser
lens
SI prism 1
SI prism 2
H-LED
H-LCD prism
Eyepiece lens
V-LCD
V-LCD
prism
Metering
sensor
SI lens 2
SI mirror
SI lens 1 SI-LCD
Focusing
screen
Viewfinder Optics1