Tamron also has a 10-24 mm 3.5-4.5 that seems to fit your needs. However, I have the older Tamron 11-18 4.5-5.6 (discontinued, I think), and it is soft and has substantial chromatic abberations not only in the corners. They might have improved this in the newer versions, but I would probably go for Tokina if I were to buy today, unless I came over some test showing stunning performance of the Tamron. The Tamron17-50, on the other side, is a very sharp lens, that also fit for landscape photography where you don't need fast (USM) autofocus.


Lars