Curious about how Sigma’s 50mm f/1.4 EX DG HSM fares against the name brand competition? Well if you’re thinkin about ditching your current 50mm f/1.4 wait just a second, at least check out Peter Dumont’s little comparison of the Sigma 50mm f/1.4 EX DG HSM vs the Canon 50mm f/1.4. He has some comparison pictures from f/1.4 to f/5.6, that might convince you to stick with your current 50mm:

The sigma 50mm lens is a big hunk of glass that feels great on a 5D, and the manual focus ring is very nice indeed,
but as it didn’t outperform my canon lens, I have returned the sigma to the shop it came from.
I can heartily recommend this wine though .

-Peter Dumont

Get the comparison here.