Roger and Aaron over at LensRentals.com have completed their resolution testing of a host of supertelephoto zoom lenses. The Sigma 50-500 OS and Canon 100-400 were the two big competitors to the new Tamron 150-600 VC.
The Tamron is the least expensive of the bunch and held up very well against others in its class. While it’s not clearly the best resolving lens. The price, focal range & performance will be a big winner for a lot of people.
Summary from LensRentals.com
“My summary would be that the selection between a Tamron 150-600, Canon 100-400 IS, and Sigma 50-500 OS should be made on criteria other than MTF 50. There are some minor differences in resolution, but nothing that makes one clearly better than another. Price, weight, autofocus accuracy, effectiveness of vibration control, and a number of other factors (did I mention price?) are more important considerations when choosing among these lenses.
It’s pretty obvious that the Tamron has both 600mm range and the lowest price. These tests, and everything I see from photographers using the lens in the field, support that it’s of at least equal image quality. Some people will prefer the extra wide range of the Sigma, others the lighter weight of the Canon. But for a lot of people, the Tamron is going to be the best bang for the buck.”