after going thru my need, i decided on sigma 17-50 instead tokina 11-16. The price here cheapest is 1039 with 2 to 2.5 years of warranty with 2 time free calibration. In hk , it selling as local set at 4750 (check with hk , their very own photo site: DNHome) which is 778 sing. it is almost 300 different. but the warranty part still not clear.