Page 1 of 3
Special thanks to Rainer Deissler for providing this lens!
Back in November 2004 Canon released a long-awaited ultra-wide zoom for their EF-S compatible
(consumer) DSLRs - the EF-S 10-22mm f/3.5-4.5 USM. Till then Canon users had to rely on
third-party zooms or fix-focals to cover the range below 16mm ... or upgrade to the pricey
EOS 1D line-up - something which was and still is way out of scope for most mortals.
The EF-S naming refers to Short-back focus design which is only compatible to
APS-C EOS SLRs starting with the EOS 300D (Digital Rebel). EF-S lenses feature a protruding rear
element which requires a special mirror design to avoid a collision of mirror and the rear part
of the lens. The principal idea is the reduce the distance of lens to the sensor which can
translate to a better lens design - on paper at least.
On Canon APS-C DSLRs such as the EOS 350D (used for testing) its zoom range resembles ~16-35mm
on full frame cameras. One the things you notice upon first contact is its (pseudo-)IF
design - the lens does NOT extend during zooming. There is a moving inner tube according
to the zoom position (similar to full-frame Canon ultra-wide zooms) but this does not affect
the physical length of the lens. It makes still sense to add a filter to shield this portion
of the lens. Officially the lens is not sealed and therefore not dust-proof though - this feature
is limited to recent L class lenses.
The lens construction is made of 13 elements in 10 groups including 1 S-UD and 3 aspherical
elements. Its aperture mechanism features 6 circular aperture blades. With a size
of 83x89mm and 385g it remains relatively compact. The filter size is 77mm.
Surprisingly the build quality feels quite a bit better than with its
cousin - the EF-S 17-85mm f/4-5.6 USM IS. The focus ring remains in line with the
usual consumer-grade quality but the broad rubberized zoom ring feels pretty smooth.
The plastic quality is very decent (not yet L class quality though). The constant
length throughout the zoom range certainly helps to keep the positive impression.
The lens has a very fast and near silent USM (ultrasonic) AF drive which provides full-time
manual focusing in one-shot AF mode. The minimal focus distance is 0.24m resulting in a
max. magnification of 1:6 at 22mm.