Bill Emmett wrote:
...I would suggest you take the advice of a previous post, and look into the Sigma, or the Tamron 18-270mm lens. The image quality will not be the same as the "L" quality lens, but both have some sort of IS. The cost of the Tamron will be less than the cost of the Canon 18-135mm. I think Tamron has a rebate running right now, and is priced at about $400.00. The Sigma lens is probably about the same.
B
From my experience, I have found the image quality of the Tamron and Sigma lens to be okay. I would go for the Canon 'L' series lens for the exceptional auto focus. Quick AF is very important for my style of photography. Canon does not release the algorithms for their lens electronics to third party manufacturers. This leaves Tamron and Sigma to reverse engineer the lens electronics to get the information. This leads to compatibility and AF issues with some lens and body combinations. Nikon releases this information to third party manufacturers and this makes for more compatible lens and AF.