I once tested the Tammy and had a Sigma 120-400 (mind you, not the 150-500!). Read my findings on the Tamron 200-500 here
and my Sigma 120-400 review there
- The Tamron disappointed me and I gave it back. I assume that it suffered form manufacturing tolerances as photozone had good things to say about it here
, but only for a second copy provided by Tamron. So it seems that if you're lucky, you might get a good copy from Tamron. Unfortunately the same holds true for Sigma lenses.
- The Sigma 120-400 shows nice potential albeit with some haloing and a drop in performance at the long end. I was unfortunately struggling with the OS (image stabilization) which gave only about one stop of effect. But other people were quite content with the efficiency of the OS, so again, it might have been the effect of some quality control issue.
- My own expectation
for the Sigma 150-500 would be the following: Sharpness at the long end should be a little better than with the 120-400 (at least at 400mm) so overall sharpness should be pretty good. And if you're lucky you should also get a good working OS.
So there are some "ifs" in my summary, but when I had to decide which lens to give a try I'd certainly go for the Sigma because of the better zoom-range, the more modern design and the OS.
Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews
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