Replacing Rebel XT kit lens: Sigma 17-70 vs Tamron 17-50 vs Other

[swiftaw]

I am thinking about replacing the kit lens on my Digital Rebel (350D) and have been looking at the Sigma 17-70 and the Tamron 17-50. The replacement lens would need to be fairly multifunctional so that I have some flexibility of use, although I mostly take photos of urban scenes and landscapes.

Does anyone have any thoughts on these two lenses, or any others I might want to consider (my budget isn't unlimited)

Also, if it helps to know, I also have these lenses as well as the kit lens:
Canon EF 75-300mm f/4-5.6 III USM
Canon EF 50mm f/1.8 II (great lens for the price)

 

[M@lew]

I'm also in almost the same situation as you, except there may be a chance that I'll take the jump to the 17-40L or 17-55 IS USM but if I can't manage to get one of those it's definitely the Sigma or Tamron.

The way I see it is pick if you want a constant aperture or a longer focal length. At the moment the Sigma is around $150 cheaper than the Tamron and although it's only f/2.8 at 17mm, you have the 50mm f/1.8 should you want a wider aperture at a longer focal length.

 

[swiftaw]

I guess I also should have asked:

Do these lenses provide a (significant) quality increase over the kit lens?

 

[M@lew]

Both lenses have better quality than the kit lens, with the Tamron having slightly better than the Sigma I think.

 

[twodeko]

i replaced my kit lens with a 17-40 f4/L and it has been wonderful. i also purchased the 50mm f/1.8 and use that extensively as well, but the 17-40 takes great landscape pictures.