Overall the Tamron SP AF11-18mm F/4.5-5.6 Di-II LD Aspherical (IF) shows good
performance. Sharpness is consistant across all apertures and focal lengths, flare is very
well controlled and vignetting is very slight. There is visible chromatic aberration and
barrel distortion, especially at the shorter focal lengths. However in extreme wideangle
lenses of this type such aberrations are probably to be expected.
Although coverage is only enough for an APS-C sensor camera at 11mm, the lens will
mount and operate on any EOS body. Though there will be corner vignetting at 11mm,
coverage increases to full frame at around 14-15mm, though there are no guarantees on
image edge quality as the lens will be operating outside its design parameters there.
Still, I think this is a better option than EF-S lenses, which can only be mounted on EF-S
bodies (Digital Rebel, Digital Rebel XT and EOS 20D).
The APS-C coverage is sufficient for any Nikon or Konica-Minolta DSLR and the Tamron SP
AF11-18mm F/4.5-5.6 Di-II LD Aspherical (IF) is available in those mounts as well as Canon
EOS.
The lens appears to be well constructed and is among the smallest and lightest lenses
covering this focal length range. It's supplied with a hood (optimized for use on APS-C
sized sensor cameras) and comes with the standard 6 year Tamron warranty.