[jjynwa]

Hi, I'm thinking of getting a walkabout zoom lens. Either the 17-70mm F2.8-4 HSM OS or the old version which is 17-70mm F2.8-4.5 Non-HSM.

Any Sigma 17-70mm F2.8-4 HSM OS users around? How's the HSM and OS capability? In terms of IQ wise, any significant difference?

Thanks!

[jct us101]

If you have a Pentax body with Shake Reduction, then I doubt you'll really need the OS, and the autofocus on the original wasn't bad at all. I owned the original, and I thought it was a great and very sharp lens itself, sharper than most primes that I have ever used too. Here's some photos from it.

[bdery]

The first version, non OS, is an excellent lens, my main lens actually. I wouldn't buy the new one just because of OS (or SR as Pentax users call it). Optically it seems to be a tiny tiny tad worse than the older version, but it's a fine hair's difference. The new version is faster at the wide end, and smaller I think.

You'd be happy with both.