I have been using the Sigma 17-70 for shooting landscapes and for my walk-around lens and have really enjoyed it and have been very pleased with the results.
But I am shooting a wedding and I am tempted to go to the Canon 17-55 for the IS and for the constant 2.8.
Has anyone made the same change? Did you miss the extra reach? Is there noticable difference in IQ?
Nic



