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01-24-2009, 08:41 PM   #1
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Opinions: Sigma 17-70 vs. Tamron 28-75

Would those of you who have had both the Tamron 28-75 and Sigma 17-70 voice their opinion as to which one they would keep ( for IQ etc please.

Although they are not obviously direct competitors the range overlaps quite a bit and I know the Sigma is wider and can be quite a decent close up lens.

I have both but I feel I would use a 2nd body more rather than keep both.

Thank you.


01-24-2009, 08:59 PM   #2
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Obviously, both lenses are great lenses, but to me, the Sigma would be the more practical choice, as it covers wider range of FLs. If you're looking for prime-quality at a wider angle than your 43, then adding something like a DA21 or a DA15, when it comes out, would nicely complement your 43. OTOH, if you were to keep your 28-75, the 15 or 21 would also work well with it for a wider angle choice, if you find yourself not needing wide-angle that often.

If you do decide to keep the Sigma 17-70, one thing you might consider doing down the road is trading it in for a DA17-70 so you can get the constant f4 and SDM. I'm considering doing that very thing with the DA16-45 I have. From what I've gathered, the IQ of the DA17-70 is similar to that of the DA16-45, which I like very much; the only problem i have with the 16-45 is that it sometimes doesn't go quite long enough for me.

01-24-2009, 09:58 PM   #3
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Well, if you have both, why not keep the one that you find yourself using more often? I think the differences between these two lenses comes down to more than just speed. Namely, focal length range and speed. I cannot comment on the IQ of the tammy since I've never used one, but I had the sigma 17-70 and found the f/4.5 at the tele end too slow, however I do miss the close focusing capabilities.
01-24-2009, 10:29 PM   #4
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Yes, I do find the question curious if you have both already... we should be asking you which is "better".

I personally found the Tamron to be quite an excellent lens. But after someone's post about how badly it AF'ed near intinity @ f/2.8 I gave it a try and sure enough, terribly bad pictures (midtown NYC). I switched to manual focus and the images out resolved my A 50/1.4. The Tami is also often a 'flatter' color rendering. I find I usually have to punch it up in Lightroom to be pleasing. How do you find the Sigma compares in that manner Rmpjr7?

01-25-2009, 12:10 AM   #5
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As a Sigma 17-70mm owner, I find it has a very useful range of focal lengths and use it for travel if I can only bring one lens.
Not so hot about the Tamron 28-75mm. It may be f/2.8 but it simply isn't wide enough on digital imo.
01-25-2009, 07:29 AM   #6
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I'm following this thread because i'm about to decide which lens should i buy.

Most of the people are saying that the tamron 28-75 is a good performer, and by judging the number of owners around here, it's certainly so.

One piece of data that i cannot find, is the actual aperture range vs focal range that the Sigma lens has. I've never seen that lens anywhere so i cannot tell. Since the Tamron is a constant 2.8, you do not have to worry about this, but the Sigma, a 2.8-4.5 lens, does it keep his 2.8 aperture right at 17mm and then it jumps to 3.5 at 19mm? (like the 18-250, it's at 3.5 at 18mm but as soon you turn the zoom ring, it's jumps to 4.0). Anyone would kindly try to write down when the maximum aperture changes on the Sigma up to 4.5?

01-25-2009, 07:46 AM   #7
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OP...which lens do you use more often? Keep that one.

01-25-2009, 10:36 AM   #8
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QuoteOriginally posted by Powermarc Quote
Anyone would kindly try to write down when the maximum aperture changes on the Sigma up to 4.5?
From PBase website:

Sigma 1770DC focal length to aperture break-down:
17-20mm 2.8
21-24mm 3.2
25-34mm 3.5
35-54mm 4.0
55-70mm 4.5

01-25-2009, 02:25 PM   #9
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I didn't realize the Sigi was variable aperture. I'd keep the Tami in that case. I don't like the "surprise" of aperture changing on me when I have my parameters set-up and I just change focal length. OT, but I am interested however is Sigma's new 24-75/2.8.
01-25-2009, 07:25 PM   #10
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I shoot Raw and I honestly cannot see much difference in IQ, or color, although the Sigma may be a tad sharper.

I think I will probably sell the Tamron because I love my 43 ltd which covers the 28end of the Tammy.

Thanks to all who answered.


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