Canon recently updated their aging EF 24-70mm f/2.8 with a much more expensive (but superb) EF 24-70mm f/2.8 Mark II version to keep up with the times. While Tamron also released their own Tamron SP 24-70mm F/2.8 Di VC USD which not only offers the same range, but offers image stabilization as well.
Krish compares five of these workhorses in the recent DigitalRev with photos and specification table to make sense of it all.
You’ll see Nikon vs. Canon, 3rd Party (Sigma vs. Tamron) going at it, and even a comparison between the original Canon 24-70 and the new Mark II version. Here’s the link to the article.
Before you go however, don’t miss Kai’s review of the Canon EF 24-70mm f/2.8 Mark II.