DxOMark posted their Tamron SP 150-600mm f/5-6.3 Di VC USD G2 lens (for Canon EF mount) review and test results: The Tamron SP 150-600mm f/5-6.3 Di VC USD G2 lens achieved an overall DxOMark score of 19 points. Tested on the 50MP Canon EOS 5DS R, the new Tamron SP 150-600mm F5-6.3 G2 model has good sharpness levels, particularly at the shorter end of the zoom range.
DxOMark from Conclusion:
Tamron has done much more than just a casual update of this lens, having totally redesigned the exterior, added improved weather sealing and a new quick-locking mechanism to maintain a set focal length, and even included a built-in Arca-Swiss compatible lens plate in the foot of the removable tripod collar.
Tamron has also refreshed the optical construction by adding an extra element to the rear. While this has resulted in a very slight drop in sharpness with respect to its predecessor (mostly in the outer zones), it’s still a great performer optically and it remains a hugely attractive option at a highly competitive price.
You can read the full review at DxOMark.