only down side it is huge for its range for crop sensor.I was thinking to get either Canon 17-55mm F2.8 or Tamron 17-50mm F2.8 few months ago, but went for Canon 17-55mm F2.8 as tamron is noisy when focusing, imagine you are in a quite restaurant, everyone will start looking at you. Another reason is Canon has the IS which is very important to me and it comes in handy when the time is right.
