In response to a few posts:
- Tamron is listed at $550 cheaper than the Canon. I think an earlier poster mistakenly thought that they were closer in price.
- I agree that the contrast is better on the Canon.
- Weight is identical, but the Tamron is a little smaller (negligibly).
- I'll keep my Canon primarily because of its performance on the teleconverters, which I do use sometimes. I wonder if TDP did its tests with Tamron or Canon teleconverters. I'd love to see a comparison of the Tammy on both sets to see which work better, and if using its own, native teleconverter might even up the performance. If, however, I were buying new, I think the price would push me to Tamron.