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02-05-2011, 11:59 AM   #16
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Loren E How do they compare in build quality? Of course neither is weather resistant but if you were to trek around to remote places and see some harsh conditions is does one stand out over another as more likely to get drizzled on a little and make it, or take a few bumps and be no worse for the wear?
Loren, the 17-50mm is built very well. I bought it to accompany me on my extensive, 4-season hiking, throughout the mountains of the Eastern US.

Loren E: I am researching but having trouble finding out: are they both screw-drive AF? And do both have quick-shift from auto to manual focus?
The 17-50 Tamron is screw driven. The new Sigma 17-50 2.8 OS is HSM.

LorenE:This is going to be my low-light lens, so I want both acceptable performance wide-open at 2.8 as well as acceptable auto-focus accuracy in lower light.....I am reading the sigma doesn't do great at F2.8 but not hearing much more then that.....
The Tamron is excelllent wide open, better than any of the lenses mentioned in this thread, retaining sharpness uniformity, even to the extreme borders. The new Sigma 17-50 HSM OS, is sharper in the center wide open, but does not retain its uniformity as well to the extreme borders. The 18-50 Sigma is not nearly as good as the Tamron wide open.

Lorene: Also the sigma has a similar minimum focusing distance, 11 inches, so I am guessing that macro-wise they would do a similar job?
I have shot with the Tamron, not the Sigma--the Tamron is excellent @ close focus. I'm sure you can find pics with the Sigma at close focus if you search the Sigma Club. I advise you to search out these clubs for shots--it helps.

Here is a recent shot (this Fall) with the Tamron 17-50mm 2.8:

02-05-2011, 12:34 PM   #17
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Personally, given those choices, I would go for the Sigma 17-50mm, due to HSM. Fast, silent AF is very useful for a normal lens. I went for the 16-50mm, though. It's been two years now without any issues. What sealed the deal for me was the weather-sealing, which has been extremely useful for me as well.

Regarding the macro, the Sigma has a minimum focusing distance of 20cm which translates to 1:3, while the Tamron has 27cm and 1:4.5. I would not base my purchase on this small difference and would personally choose the Tamron!
02-05-2011, 03:11 PM   #18
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Beautiful colors in that image JT.

To clarify guys, I am trying to decide between the tamron 17-50 and the sigma 18-50 ex dc....not the HSM version and not the macro version, this is the earlier version that came out I think in 2004.

Thanks! -LE
02-05-2011, 06:06 PM   #19
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Well, it's a shame you're not considering the macro version... I got it today, and went out for some quick shots. I'm quite impressed.

All at f/2.8.

Some more shots here:

Sigma 18-50 f/2.8 EX DC Macro - a set on Flickr

Hope this hasn't made things more complicated!

02-05-2011, 07:14 PM   #20
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Oh man great shots. I am going to need to use a circular polarizer on this lens and want it to only be a temporary lens until pentax figures out the DA* 16-50 so I can get the weather-sealing, so I want to be able to trade filters with my DA* 60-250 without the pain of a step-down ring on a wide angle, and they changed this lens to 72mm filter for the macro version. That's why I want the non macro 67mm version or the tamron 17-50, and it is sounding like the tamron is the better lens but also a bit more expensive
02-05-2011, 07:26 PM   #21
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Just get the tamron 17-50. I know people who is so satisfied with it that they do not feel the need for the 16-50mm. The 50-135mm however.... Thats a different story.
02-05-2011, 07:30 PM   #22
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The tammy sounds like a great lens, sounds like it beats the sigma I am looking at. I am torn between chancing SDM issues on the DA* 16-50 for the weather-sealing or going with the unsealed tamron. The 50-135 is not a lens that fits in with my kit, as I am getting a 60-250, which luckily sounds like it is less prone to SDM problems than the other two.
02-05-2011, 07:43 PM   #23
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I've had a Sigma 18-50mm f2.8 EX DC MACRO for about a year now,
use it 99% of the time at f2.8 for night / action photography, solid & reliable performer.

Just for fun a few weeks ago I purchased a Tamron 17-50mm f2.8 and kept it a few days to
do some side by side testing, for sure the extra 1mm (x1.5) at the wide end was
noticeable but can't say it was much sharper wide open than my Sigma.

What I did notice immediately is the lower overall build quality of the Tamron,
very 'plastic' feeling compared to my Sigma.

I returned it a few days later, despite most online reviews that
rate it better than the Sigma, I was not very impressed by the Tamron.



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