Tamron 17-50 f2.8 or Sigma 17-70 f2.8-4.0 HSM?

Hello,

I am considering buying either the Tamron 17-50 f2.8 (435g) or the Sigma 17-70 f2.8-4.0 HSM -- to get the f2.8 aperture in a wide-angle (16-17mm) zoom. My narrowing it to these two is partly an issue of weight and cost…

The Sony 16-50 f2.8 and the Sigma 17-50 f2.8 both have SSM/HSM focusing, the best IQ reviews, but seem like they would be too heavy on my A55 (at 575g each). The Tamron is 435g and the Sigma 17-70 is 530g. (Another option, the Sony 16-80 Z, is f3.5-4.5 and no SSM.)

The Sony and Sigma f2.8 both cost about $670-700, and the 16-80 Z is $850, while my two choices cost about $435.

I have read dyxum.com reviews, though there are less than 10 for the Sigma. The reviews in photozone.de, slrgear.com, and lenstip.com suggest that the Tamron 17-50 has a bit better IQ. But the Sigma 17-70 has HSM (good for video) and perhaps better CA control. The Tamron is a steady f2.8 while the Sigma is f2.8 only up to 20-22mm; after that, it is essentially a f3.5-4.0 lens.

In the end, I might order both from a company where I can return one within 14 days. By I am very interested in hearing any real-world experience in comparing these two choices.

Has anyone tried both the Tamron 17-50 to the Sigma 17-70? What is your practical evaluation of them? What would you recommend?

Any other options in this price range to consider?

Thanks in advance,

William
--

'Let the beauty of what you love be what you do. Sell your cleverness and buy bewilderment. Cleverness is mere opinion, bewilderment is intuition.' -- Rumi