The Digital Picture has completed their review of the brand new Tamron 150-600mm f/5-6.3 Di VC USD G2 and it looks to be a really good supertelephoto zoom option.
On price and value
The Tamron 150-600mm f/5-6.3 Di VC USD G2 Lens hit the street costing about 30% more than its predecessor. The original lens was and remains a bargain and the difference between the two lenses must be considered whether the same descriptor applies to the new lens. We all value our money and gear differently, but based on all of is improvements, including one-shot AF accuracy and build quality, I think the G2 will be worth the difference for many photographers. So, I'll call the G2 a very good value lens as well. Among those considering this lens is going to be the cost-conscience crowd and some will likely choose the lower-priced model over the G2.
I have to admit that I didn't expect to see the second generation of Tamron's first 150-600mm VC lens arriving this soon. And, I didn't expect the upgrade to be such a substantial one. While I can't say that image quality was dramatically improved, the form and function of this lens definitely were. Read the full review