The Sigma 28-70 f/2.8 EX is a great lens for it's price if you stop it down a bit. However, as I used this lens more I took a dislike to it's softness (and purple haze) when using it at f/2.8.

After purchasing a Canon 70-200 f/2.8 USM lens for longer reach I was amazed (stunned) at how sharp this lens was and this led to my purchase of the Canon 24-70 f/2.8 L lens (although I think the 70-200 f/2.8 might be sharper than the 24-70 f/2.8 L - I'll have to run another test in the future comparing these two).

Anyway, the gallery called "Canon vs Sigma" shows a direct comparison including the full size jpg straight out of my D60 camera. The other gallery "real world tests" consist of 100% crops of the Sigma lens only (prior to buying the Canon 24-70).

Since a lot of people, particularly persons with new DSLR's, are interested in which lenses to buy I thought I'd share my findings.