Sometimes we are joking about a hypothetical 18-300mm f/1.8 to meet all our photographic needs. Well, we aren't quite there yet nor will we ever see such a lens on a DSLR but the manufacturers are at least scratching this focal length range with some 18-200mm variants and the Sigma AF 18-200mm f/3.5-6.3 DC is one of the representatives here. It is one of Sigma's DC (Digital Camera) lenses with a reduced image circle only compatible to APS-C DSLRs. The lens is available for all major APS-C DSLR systems. Within the scope of this review the Canon EOS 350D/Digital Rebel XT was used for testing. The field-of-view of this lens is equivalent to ~29-320mm on full frame cameras. Read the very nice review here