Hsm V Non hsm

Hello all, hope all is well , just wondering is there much of a difference between the two. Debating on selling my non hsm 17-70 for the hsm version. Is image quality the same??

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The newer Sigma 17-70mm has Optical Stabilisation built in so will have a different optical design I would say. Whether IQ is comparable I couldn't comment.

It is heavier though, plus you already have in-body stabilisation so I can't see it being a worthwile upgrade just for the HSM.

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My Flickr

Doesn't need to be, they often have lenses for Pentax and Sony without OS but have it in other mounts.

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Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ

In the case of the Sigma 17-70mm though, the new one has OS in all mounts.

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My Flickr

Indeed but for example the Sigma 120-400mm also has OS for the mounts besides Pentax and Sony but still the lens arrangement is the same for all mounts.
The comment you made that the lens must be optical different because it has OS doesn't need to be true.

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Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ

I don't really see any advantages going to the HSM version of the lens. The AF on the original lens is already very fast. Maybe the HSM is a little bit faster, but we are looking at milliseconds here, not night and day.

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Yves (another one of those crazy Canucks)

One advantage of HSM is that it is nearly silent. This may be useful under some circumstances.

Doesn't the newer version have a wider apertures or am I mistaken versions?
f/2.8-4 vs f/2.8-4.5

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Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ

I believe you're right Stefan - it does have a slightly wider max aperture.

I would say the pros are:
- Silent focussing
- Slightly wider aperture at the long end
- In-lens stabilisation (? - unproven if this is better than in-body but the option to use either can't hurt)

Cons:
- Additional weight

...and the unknown is the picture quality. I would guess the lens formula is slightly different as the max aperture has changed and there is likely a floating element inside for the stabilisation (that's my understanding of how it works but I could be wrong). Given that the pros and cons are relatively minor I would be nervous switching from a lens I know is great to one that may have a slightly different performance. There must be some direct comparisons out there from people who have used both.

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