Two different Sigma 17-50 f/2.8 models? What is the difference?

[uday_maripalli]

<p>I am looking to buy a used Sigma 17-50 for my new K-3 (amazon/ebay/keh/adorama etc.,). I noticed that there are two lens models that are very similar. For example, I took these two items for same from Fredmarinda store:<br>

<a href="http://astore.amazon.com/salesfredmira-20/detail/B003A6NTIG">Sigma 17-50mm f/2.8 EX DC OS HSM FLD Large Aperture Standard Zoom Lens for Pentax Digital DSLR Camera</a><br>

<a href="http://astore.amazon.com/salesfredmira-20/detail/B006IQ3W0U" target="_blank">Sigma 17-50mm F2.8 EX DC HSM Lens for Pentax SLR Cameras</a><br>

Does Sigma makes both with OS and without OS lens for Pentax mount? Will there be any difference in IQ with either of these two?<br>

Thanks.</p>

[htarragon]

<p>The one w/o OS is for Pentax. B&H has the one without OS for Pentax, the ones with OS for Canon and Nikon.</p>

[uday_maripalli]

<p>Thanks.</p>