Sigma 24-70 f/2.8 vs. Tamron 28-75 f/2.8

I've had the Tammy for some time and absolutely love it. Focus is quick, IQ is, IMHO, great. I'm thinking the only way I will ever replace this lens is if it stops working and can't be fixed.

Here is an image I capture a couple of weeks ago. This is the full image, no cropping.

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My examples with Tamron on my 5D:
http://albums.photo.ep​son.com …x?u=4298510&a=3​2248569&f=

#1 is f2.8 and some of the later ones are 100% crops. Rose image is f2.8 too. I like this lens a lot, but as many have stated about this lens - it doesn't focus well in low light. I find it front focusing in low light so I manual focus then.

Here's a qualitative review:

http://www.pbase.com/l​ightrules/exvdi

I went with the Tamron over the Sigma.

You'll find that the Tamron and Sigma are very similar, but the Tamron appears to be a tad bit sharper overall.

However, the focal length trade-off may be worth it depending on what you do.

I can't speak for the Tamron, but I have the Sigma and the two step change from Auto to Manual doesn't bother me. I love my Sigma but it's BIG (82mm front filter thread) and heavy. However, the extra 4mm on the wide end was important to me so the Tamron lost plain and simply because of that.