Camera Labs

Hey guys, I plan to buy a Tamron 200-500 but I am wondering if the Image Quality is as good as or better than the Sigma 150-500 OS. Sure the Tamron does not have stabilizer unit, but for the price, I think its worth it.

Here is the price list :
Sigma 150-500 OS : 39,000 THB ( 2 Yrs Warranty)
Tamron 200-500 : 34,000 THB (1 Yr Warranty)

Now, I can get the Tamron for 16,000 THB (No warranty, as I'll be getting it from Singapore; 100% New), yes, at half the original price, and use the difference for a monopod or tripod. My question is, which lens is sharper at 200-500mm? For anything below 200, I would be using a Tamron 70-200 2.8, so I think the 150-200 range on the Sigma would be useless. I wouldn't mind loosing stabilizer at half the cost, as I could use a monopod to help with stability. So, given that you are in this situation, which lens would you choose? Why?

Thankyou!

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.
Summary:
- 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.

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Thomas (beware: Nikon-fanboy and moderator!) My Lens Reviews, My Pictures, My Photography Blog
D800+assorted lenses

Thanks for your input. I think I'd go with Sigma, for the OS