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Press Release - ข่าวจากแคนนอน
Canon, a leader in
photographic and imaging technology, today announces the EF-S
17-85mm f/4-5.6 IS USM and EF-S 10-22mm f/3.5-4.5 USM wide-angle
EF-S zoom lenses. Targeted at advanced digital photographers, both
lenses are designed to work exclusively with Canon’s EOS 20D and
EOS 300D digital SLR cameras. The focal length ranges of the
respective lenses translates to 27-136mm and 16-35mm respectively
in 35mm film format – a spread carefully chosen by Canon to
reflect the needs of its rapidly growing base of advanced D-SLR
photographers.
Both lenses feature Canon’s ring-type Ultra
Sonic Motors (USM) for fast, near-silent auto focus, and a range
of features designed to deliver a level of image quality
approaching that of Canon’s revered L-Series professional lenses.
Standard
Ideal for travel, mid-range nature/wildlife and
general photography, the
EF-S 17-85mm f/4-5.6 IS USM is a high quality, lightweight,
all-purpose ‘standard’ zoom lens. This 5x zoom lens offers the
widest range of any lens in this class, and features Canon’s
latest optical Image Stabilizer technology, providing up to 3-stop
compensation for image blur caused by camera shake and slow
shutter speeds. With superb quality suited to semi-professional
use, the lens has a 17 element, 12 group construction, including
one double-sided aspherical element for crisp, high contrast
corner-to-corner detail.
Wide Angle
The EF-S 10-22mm f/3.5-4.5 USM is the market’s
lightest and smallest 16-35mm (35mm equivalent) zoom lens
available; ideal for landscape or indoor photography, or for
photographers wishing to experiment with pan-focus and dramatic
perspective effects. It also boasts a remarkably close focusing
distance of just 24 cm. With similar high build quality to the EF-S
17-85mm f/4-5.6 IS USM, the
EF-S 10-22mm f/3.5-4.5 USM includes a Super UD (ultra-dispersion)
glass lens and two aspherical elements in its 13 element, 10 group
construction. The non-rotating front element makes it ideal for
use with filters such as polarizing and graduated, both of which
are popular for the type of landscape photography for which the
lens is suited.
EF-S mount
Both lenses feature Canon’s EF-S lens mount,
matched to the EOS 20D and EOS 300D digital SLRs. The APS-C sized
sensor of these cameras results in an effective multiplication
factor of 1.6x the indicated focal length. While this creates an
obvious advantage for telephoto lenses, it is less beneficial when
meeting wide-angle requirements. To meet the needs of the new
digital photographers, Canon developed the wide-angle EF-S lens
mount. The EOS 20D and EOS 300D are both completely compatible
with all existing EF lenses, while EF-S lenses only fit these two
cameras. Optimized for Digital SLRs with APS-C size sensors, the
EF-S mount enables economic wide-angle solutions often required by
advanced photographers.
The ‘S’ in the EF‑S nomenclature stands for the
term ‘short back focus’. This describes the system that allows the
rear lens element of EF-S lenses to be positioned closer than
normal to the image sensor of APS-C sensor cameras. A white lens
mount index differentiates the lenses from other EF lenses, which
retain their traditional red marking. A rear rubber ring prevents
any damage in the event that an inadvertent attempt is made to
mount the lenses on non-compatible cameras.
Fast auto-focus
The ring-type USM motors found in both lenses
employ ultra-sonic frequency vibrations to drive focussing with
unrivalled speed. Canon’s ring-type USM holds the lens with
precision and accuracy, the instant it arrives at the correct
focus point and without overshoot. To further improve accuracy and
speed, the drive patterns of both lenses are tailored to
specifically match that of the EOS 20D and EOS 300D. Both lenses
also feature full-time manual focus override without risk of motor
damage.
Appealing background blur
The lenses both incorporate an EMD
(electromagnetic diaphragm), which employs an almost perfectly
circular barrel aperture. This helps create an attractive, even
background blur when the photographer minimises depth of field to
isolate a subject.
Perfect for digital photography
By optimising lens coatings, Canon’s engineers
have been effective in suppressing flare and ghosting, which are
more prone to occur with digital cameras due to reflection off the
image sensor. Coatings reduce reflections off the lens surfaces to
deliver crisp, undistorted digital images with natural colour
balance.
Distant linked flash
Both lenses include new distance metering
information, providing compatibility with the E-TTL II flash
system of the EOS 20D. When used in conjunction with Canon’s range
of EX Speedlite flash units, this allows for markedly improved
flash exposure metering.
An optional lens hood accessory is available
for both lenses.
In harmony with the environment
In keeping with Canon’s stringent environmental
policy, only lead free glass is used in the lens’ optics.
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