Specifications

III. PERFORMANCE 14
Live View Function
T
he EOS 40D's 22mm eyepoint is the distance
a
t which the viewfinder image area can be
v
iewed without any vignetting of the viewfinder
o
n all 4 edges. Normally, most manufacturers
d
efine the eyepoint as the distance at which
b
oth the viewfinder image area and information
d
isplay are visible. The 22mm specification for
the 40D meets both criteria, absence of cut-off
as well as visibility of both image and information. The basic configuration of the super-
imposed display optics is the same as that of the EOS 30D.
Interchangeable focusing screens are a new and significant feature of the EOS 40D. The
Ef-series focusing screens have been newly developed. 3 screens, the Ef-A Standard
Precision Matte, the Ef-D Precision Matte with Grid, and the Ef-S Super Precision Matte
are available. All 3 focusing screens have a fresnel lens area and are produced by a new
molding method (first used on the EOS-1D Mark III’s focusing screen Ec-C IV) that provides
excellent transfer characteristics. Consequently, even the Standard Precision Matte
screen offers improved performance. The Grid Type screen is particularly convenient for
controlling horizontal positioning and as an aid to overall composition. The Super-Precision
screen makes it easier to find the “sweet spot” of focus when using a lens that is faster
than f/2.8 and is also effective in difficult, manual focus conditions.
The information display inside the finder has been enhanced in several ways: the ISO is
always displayed, even when Auto ISO is set; a Black and White setting alert has been
added; and the maximum burst possible is displayed in two digits instead of one. The
LCD monitor can also be used to display the settings of the shooting functions.
One of the major aspects of the EOS-1D Mark III is the inclusion of a fully-functional Live
View Function. The EOS 40D has it as well, along with some useful improvements. In
addition to the Live View Function found in the EOS-1D Mark III, the EOS 40D enables
"AF during Live View Function" and "Silent shooting." (Note: Live View Function is only
possible with the Creative Zone modes.)
The EOS 40D's CMOS sensor has an electronic 1st-curtain shutter function, enabling
shooting with the mechanical shutter completely open. With Live View Function image
displayed, the 40D can shift seamlessly to slit exposures with the electronic 1st-curtain
shutter, enabling silent shooting which is not possible with a mechanical 1st-curtain
shutter. This electronic 1st-curtain shutter uses a unique high-speed scanning and elec-
tronic reset system that accurately mimics the EOS 40D's high-speed mechanical shutter
Ef-A Standard
Precision Matte
Ef-D Precision
Matte Grid
Ef-S Super
Precision Matte
F
ig. 47 Viewfinder Optics
Eyepiece lens 1
Eyepiece lens 2
Eyepiece lens 3
LCD in the viewfinder
Main mirror
Focusing
screen
Pentaprism
S
I lens
SI reflective plate
V
iewfinder Optics