Bryan Carnathan has just posted a detailed review of the newly released Tamron SP 24-70mm f/2.8 Di VC USD G2 lens at the-digital-picture.com. This new lens is priced less than most of the competition such as Sigma 24-70mm f/2.8 DG OS HSM Art lens. He tested it on Canon EOS 5DS R and Canon EOS-1DX Mark II and highly recommended it!
Conclusion from The-Digital-Picture, ” And although this lens is not inexpensive, it is priced less than most of its competition and it represents a good value. I’d like the zoom ring to be positioned behind the focus ring and for better peripheral AF point accuracy, but with a highly-useful focal length range, low light action stopping capabilities, extreme low light hand-holding capabilities, very good overall image quality and a nice build quality, the Tamron 24-70mm f/2.8 VC G2 Lens is a good option for the potentially-most-used lens in the kit....”
Read More Tamron Lens Rumors