V. PERFORMANCE, DESIGN AND CONSTRUCTION
20
New Lenses
To make the camera smaller, the external interface connection circuit board has been
separated from the digital control board and both sides are used. It has the USB port
(MINI B), conforming to USB 2.0 Hi-Speed, and the video OUT terminal.
The double-sided flash circuit board is the same as the unit in the EOS 20D. It has the
flash circuitry, electronic X circuit and the camera orientation circuit.
The power source circuit board has four layers. It has the power source circuits that
generate the voltage necessary to operate the camera’s circuits.
The sixth, rigid, printed board is on the improved shutter unit.
Two new and very different lenses that professional and advanced amateur photographers
will find exceptionally appealing will become available at roughly the time that the
EOS 30D reaches dealers. They are a large aperture standard zoom and an ultra-fast
medium telephoto.
The EF-S 17–55mm f/2.8 IS USM offers superb image quality,
on par with L Series lenses. It has a large maximum aperture
which, combined with higher shutter speeds, can minimize
subject motion blur. Shallow depth-of-field for separation of a
subject from its background is much easier to achieve. The f/2.8
maximum aperture allows a bright finder and extremely precise
focusing with f/2.8-compatible AF sensors. The internal
stabilization has a sharpness benefit equivalent to a three stop
faster shutter speed. Combining f/2.8 with IS makes the new
lens outstanding in low light. As an EF-S lens, the new zoom is
smaller, lighter and handier than a lens of similar specifications could be, but covers
the full 24 x 36mm frame. This new lens would certainly be the “best match” for the
EOS 30D except that it causes some vignetting when the built-in flash is used. The
EF-S 17–55mm f/2.8 IS USM is expected to retail for $1,149 and is sure to be adopted
by photographers of every sort.
The EF 85mm f/1.2L II USM is a revision of the EF 85mm f/1.2L
USM lens introduced in 1989. Its enormous maximum aperture
and handy focal length made it a favorite of wedding, portrait and
sports photographers. While its image quality has remained a
benchmark, general improvements in AF speed over its years of
service make it an excellent candidate for an AF update. A ring
USM drive, a high-speed CPU and optimized AF algorithms achieve
a great increase in AF speed over the older lens (roughly 1.8x, depending upon camera
and conditions). Lens coatings have been optimized as well, minimizing ghosting and
flare. Distance information is now provided for flash exposure calculations. The new
lens now has a round aperture that helps to produce a beautiful background blur. The
new 85mm has the same optical system as its predecessor, 8 elements in 7 groups.
The ground aspherical element, in the third position from the front, minimizes
aberrations and provides superb image quality with high resolution and high contrast,
even at maximum aperture, true to its L Series heritage. The lens uses a floating
construction in which the final group (lens element 8) is fixed and the other lens groups
EF 85mm f/1.2L II USM
EF-S 17-55mm f/2.8 IS USM
