Would there be a great difference between the quality of photographs of the combinations above. I have a 5D with a 24-105L but need the 2.8. I also need a back up camera so I will be buying the 40D. Also, the weight factor might be more advantageous as the first combo is about 1300g vs 1700g.
Any one know anything about the sigma 24-70 2.8 as it weighs less than the canon equivalent is half the price and I am not sure if it could fit on both bodies. I shoot portraits and am slowly getting into function photography.
