A revamped edition of Tamron 's original 17-50mm zoom for APS-C format cameras, the Tamron SP AF 17-50mm f/2.8 XR Di II VC adds VC (Vibration Compensation), while retaining the earlier version's zoom range and constant f/2.8 aperture rating. The VC stabilisation system has an effectiveness equating to four stops, beating the three-stop stabiliser of Canon's 17-55mm f/2.8 lens. The Tamron's outright zoom range isn't as large, losing 5mm at the long end, but on the plus side, the lens is a bit smaller than the Canon.