Wide angle lens.
 

I am going to italy on a school trip and need a wide angle lens to accompany my pentax k5. I will be using it mainly for architecture and landscape photography(possibly street photography aswell) and preferably need the widest lens possible. I have looked at the sigma 8-16mm and the tamron 10-24mm but can't decide which is better; the tam is cheaper (£30 cheaper from park cameras) but the sigma has that extra 2mm. Any experiences with any of them would be most appreciated. Or any other suggestions. My budget is about £420 or lower. Thanks in advance.
Guppy :)

I've not used either lens, but 2mm at the wide end will make quite a difference...

Sigma
 

Hi, I have been using the Sigma 10-20mm for about a year or so now for both landscapes and city shots , and it is my most used lens, I can't fault it, and it is within your budget!:)