Which APS-C Alpha to buy?

The Sony/Minolta version of the Sigma 17-50mm F/2.8 OS EX DC HSM doesn't have in-lens OS (check the manufacturers website).  You'd be far better off with the series 1 Sigma AF 17-70mm F/2.8-4.5 DC Macro which is a superb performer (I have one if you want it) as even the series 2 Sigma AF 17-70mm F/2.8-4 DC OS version for Sony/Minolta also doesn't have in-lens OS.

Why Sigma and Tamron do this is beyond my understanding because they produce the in-lens OS lenses for Pentax and Olympus which have in-body IS systems the same a Sony/Minolta.

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Mark @ Sonolta * Photography