[jeffshaddix]

Woohoo! The Sigma 17-50 2.8 OS HSM FLD is now available in Pentax mount! I've been waiting for this lens to get released for a while. The same lens has been reviewed in Canon mount by a few sites. Here's an excerpt from the lenstip.com article:

"The Sigma 17–50 mm is not a flawless device but neither are so its most serious competitors which are more expensive. The Nikkor overall seems to be an optically better lens but it is much more pricey than the Sigma and doesn’t feature image stabilization. The optics of the Sigma and the Canon are very similar – both boast silent and quick autofocus mechanism and stabilization. Sigma’s advantage consists of a better warranty and a bit lower price.

For the Sony Alfa system reflex cameras users the Sigma 17-50 mm can be a very interesting suggestion because Sony doesn’t offer such a lens in its line-up so the competition is definitely less fierce. It won’t be so easy in the case of Pentax because the 16-50 mm f/2.8 model from that company tempts with a wider angle of view although it is optically worse and more expensive than the Sigma.

To sum up the Sigma 17–50 mm f/2.8 EX DC OS HSM will find many satisfied users for sure. It would be difficult not to be satisfied when you can take photos as good as or even better than the brand name competitors using a cheaper lens."

I think with the arguably better optics, and significantly better OS than Pentax's SR, and a more reliable HSM than Pentax's SDM, this lens will be a huge hit for the Pentax community.

Personally I love Pentax prime lenses, but Sigma is make strong headway in their zooms. I sincerely hope they continue to support the Pentax mount going forward.

Anyway, anyone have this lens yet in Pentax mount? Any comparisons to the 16-50? I'd love to see some reviews.

By the way the lens is currently selling for $669 in the states on Amazon (link).

[Adam]

Great news! Could someone add it to the lens database?

[pop4]

I picked mine up about a week and a half ago, although I haven't had too much of a play with it since I also received a DA10-17mm fisheye the next day, and have been too busy having fun with that. It's an EX lens and feels solid and well built, but because it doesn't have full time manual, and the focusing ring rotates while focusing, and also because the barrel extends when zooming, it feels like it's just a notch below the Sigma 50mm F1.4 and Sigma 70-200mm F2.8 HSM II, which are also EX lenses. AF is quiet and fast, probably helped in part with the really short focusing throw. Image quality wise, in my limited use so far, there's nothing to complain about, and is sharper than my 17-70mm F2.8-4.5.

[danielausparis]

By the way the lens is currently selling for $669 in the states on Amazon (link).

Aha? They try to sell it for twice the price of the (tough to beat) Tamron 17-50? Marketing has definitively some mysteries...

[pop4]

So I've had my copy of this lens for about three weeks now, and I've had a chance to use it a few times, and what can I say about it? Nothing much really, the lens just works and I don't have anything to complain about the photos that this lens can create. So the adage is true that people tend to read about problems or issues with (insert lens/camera here), but nothing much when said lens/camera just works,

However, I guess that doesn't help those who want more info about this lens, so let me rack my brains and see what I can come up with:
- the HSM focusing is nice, nice and quiet. I would take HSM over screw-drive any day. SDM...not so sure
- IQ-wise, I haven't shot much at f/2.8, but at f/8 and f/11, it's sharp!
- the lens hood, when you take it on and off, turns a bit looser than I would like and also doesn't lock in as well as I would like (and also compared to my other lenses). I'm not sure if it's specific to my copy, or a characteristic of the lens hood of all copies of this lens, but it's nothing a bit of electrical tape didn't fix.
- the OS (lens) works, but not in conjunction with SR (camera), i.e. use one or the other, not both, otherwise the images actually turn out worse. I just tend to use SR and leave the OS off
- if you shake the lens, there's a slight rattling sound. That's due to the OS element and is normal; someone on POTN got really worried when they found out their lens rattled, but an email to Sigma confirmed that it was normal

So is this lens worth the extra $$ over the Sigma 18-50mm F2.8 and Tamron 17-50mm, and is it a viable alternative to the DA* 16-50mm F2.8?
For me, it was, and I don't regret the decision at all. For you? Well, that's up to you to decide...

[Jasvox]

Sounds good. You do pay for the OS I reckon and compared to the VC version of the Tamron 17-50/2.8, its very competitively priced. (I wouldnt want to pay for the OS/VC since we have it in our camera bodies already, but if I had a second system and wanted the OS/VC, I may be inclined to lean toward the Sigma.)

Jason

[Eruditass]

Does this have optical improvements of the previous generation of the Sigma without OS?

[pop4]

Sounds good. You do pay for the OS I reckon and compared to the VC version of the Tamron 17-50/2.8, its very competitively priced. (I wouldnt want to pay for the OS/VC since we have it in our camera bodies already, but if I had a second system and wanted the OS/VC, I may be inclined to lean toward the Sigma.)

While the OS would add to the costs, it wasn't something that I worried about since we have SR already. What I did care about was HSM, and I do like my HSM (I've got 2 others).

Does this have optical improvements of the previous generation of the Sigma without OS?

This newer 17-50mm F2.8 EX DC OS HSM has 17 elements in 13 groups.
The older 18-50mm F2.8 EX DC Macro has 15 elements in 13 groups.
So the optical design is slightly different, though I don't know enough about optics to make further comment on that.

[driftingbunnies]

Any news on this lens? I'm not sure whether or not the DA*16-50 is worth the extra 90 bucks over the new sigma

[Rory]

The DA* is supposed to be rather slow. No news on this one being faster, but traditionally, HSM has been faster. It bugs me this doesn't have quick shift, though, like the Sigma 50mm.

[pop4]

I've never had any experience with SDM, but I find the HSM on this lens adequately fast. And no, unfortunately this lens doesn't have quick shift, but it does have a AF/MF switch on the lens barrel, so you can quickly flick it to MF and voila, there's your quick shift

[Jewelltrail]

I read the review for it over @ Photozone: for the most part, they liked it. Like Jason above, I would not want to pay the extra $$ for the OS when I invested in Pentax to avoid those costs. I think I'll be sticking with my Tamron 17-50 unless something more impressive than this comes along. Here is an excerpt from Photozone's summary:


The Sigma AF 17-50mm f/2.8 HSM DC EX OS is a highly competitive APS-C standard zoom lens and Sigma's best product in this class so far. It's not a flawless lens but none really is. Its biggest weakness is the performance at f/2.8 - the resolution in the image center is already exceedingly high here but the image corners are soft between 17-35mm and there's some vignetting at the extreme ends of the zoom range. However, starting at f/4 it beats or at least matches alternative products including the more expensive Canon EF-S 17-55m f/2.8 USM IS. The lens is extremely sharp across the frame here with no obvious flaw across the zoom range. The field curvature is also minimal (quite flat focus plane). Lateral CAs are not really field relevant. The distortion characteristic is about average for a lens in this class. The quality of the bokeh (out-of-focus blur) is slightly better compared to most competitors although you will naturally find prime lenses which perform better here.
The build quality is very good in absolute terms but the rotating focus ring in AF mode and, consequently, the lack of FTM (full-time manual focusing) are a bit disappointing especially because Sigma avoided theses issues in some of their other zoom lenses like the AF 8-16mm f/4.5-5.6 HSM DC. The AF is both very fast and near silent. The tested sample had also no problem with focus accuracy. Sigma's OS ("Optical Stabilizer") is, of course, a welcome new feature with an efficiency which is easily as good as its Canon counterpart.

[Entropy]

It would be very tempting if it had HSM but no OS, or the price premium of the OS were not too significant.

For example, the Sigma 18-250 HSM OS was very reasonably priced, only slightly more expensive than the Tamron 18-250 (screwdrive, no OS) was. The HSM is great, and OS is beneficial in a long lens even with in-body SR (In general, in-lens OS seems to be better in most tests at longer focal lengths while in-body SR excels at shorter focal lengths in most tests I've seen, and in-lens OS stabilizes the viewfinder and the AF sensor's view.)

On the other hand, the OS version of the Sigma 70-200 is around twice the price of the non-OS (but HSM) version. NOT worth it.

OS in a wideangle is similarly not worth it at almost any price premium - no real need for the stabilized viewfinder, no need to stablize what the AF sensor sees, and sensor-based stabilization excels at these focal lengths.