I agree that a 17-70 is likely to have better optics than something like the
18-200But I am not at all familiar with any of the Sigma lenses and there are a
number of other multi options...
I know that in a pro zoom lens, normally you won't see the max focal length go much beyond about 3 times the min focal length.
However... Because of the hassles with changing lenses in the field, having the right lens on at the right opportunity, dust risk on the sensor etc...
Do you think something with a better range will have "good enough" optics to justify doing away with the kit lenses and getting a body only?
On the body, the 500D can be bought for a fair bit less than the 550D, like a few hundred.
Main difference seems to be 15Mp compared to 18 for the 550d.
Better to put that coin towards lens?