Lens comparison, which is best?
I've searched in the discussions and on the internet and can't come to a clear choice. My Sigma 100-300mm's aperature is stuck. I have a Canon 20D. I need up to the 300mm for taking pictures of my girls playing sports. My question is what is the best option? Canon 100-300mm USM (IS is too expensive) or Sigma or Tamron? I see a lot of Canon 70-300mm, any issues with this lense? I need good, but not expensive. I love the Sigma, just wondering if the Canon is better. The price is about the same, I think.
Any help is appreciated. I talked to a professional photographer, he suggested buying another verses trying to fix the Sigma.
Thanks for any suggestions.