Originally posted by Vylen Prices in Australia are unsurprisingly terrible... From one store:
Tamron 10-24 f/3.5-4.5 $705.00
Sigma 10-20 f4-5.6 $655.00
Sigma 10-20 f/3.5 HSM $845.00
If I was lacking some money, I'd go for the Sigma f4-5.6...
If I had the money to spend, I'd go for the Sigma f/3.5...
Hopefully I'll soon have the money to spend... heheh.. save up, save up!
It would be silly to pay extra for the 3.5 10-20 IMO. The f4-5,6 is better @ 10mm, the reason you buy UWA in the first place. The little extra speed is too little consolation for a lens which is not really an upgrade to its older brother--read the conclusion, within Nikon mounts, for the 3.5 vs. the 4-5.6--especially see MTF @ 10mm in the exteme borders. f4-5.6 version gets 5 stars---the 3.5 verion gets 3 & 1/2 Stars. Even CA control is better in the f4-5.6 version. This is a no brainer.
Buy the 10-20 f4-5.6: great lens--great price.
Edit: The 3.5 version does have HSM for Pentax, which is something to consider, though for this focal range, I really see no need for HSM.