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04-29-2010, 09:55 AM   #1
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Sigma 24-70mm, Sigma 28-70mm, or Tamron 28-75mm?

Posted on DPR, but I'd like to get opinions from you fine folks, as well....

For awhile now, I was sure I wanted to get a Tamron 28-75 for my "normal" indoor constant f/2.8 lens. This would pretty become my default non-long-zoom lens.

But lately, the Tamron has gotten rarer, and more expensive. Last summer I could have gotten one for $275; now it is $459 on Amazon.

So, I started looking into alternatives, specifically the Sigma 24-70. But the Sigma is actually MORE expensive right now - $505. And the Sigma 24-70 is heavier: than the Tamron (24.6 oz vs. 18 oz). And the filter is pretty big: 82mm, which I have read can interfere sometimes with the on-board flash. (I just bought a K-x; I'm not sure if this lens would be a problem with that camera.)

But, now the plot thickens! In the course of my research, I also stumbled across the Sigma 28-70, which is $335 at 4th Street Photo, $350 at B&H. Reviews look pretty good. And the sigma is MUCH lighter: 8.6 oz. And the filter thread is much smaller: 58mm.

I don't think the 24 to 28 wide end will be a big deal for me; even with my 18-55, I don't shoot much in that range. (When using my 24-135, I find that I shoot MUCH more in the 50mm and above range.) So, I'm not all that worried about the 28mm; it was what I was going to have with the Tamron, as well.

Last summer the Sigma 24-60 was available at Cameta, but, for better or worse, I did not get one at that time. I was concerned that the 60mm would too often not be quite long enough. And now they are nowhere to be found, or way too expensive. (And I'm still not sure that I'd be happy with the 60mm max at the long end.)

So, what I have is this:
  • Tamron 28-75: $459 USD, 18 oz, 67mm thread
  • Sigma 28-70: $335 USD, 8.6 oz, 58mm thread
  • Sigma 24-70: $505 USD, 24.6 oz, 82mm thread
Now, to be honest, I'm not crazy about any of these prices. I am cheap, er, very very frugal. So, of course, I'm also checking KEH, eBay, and of course, the marketplace on this wonderful forum! (I just lost an eBay auction for the 24-70; it went for $295 + $15 s/h. I was OK with losing that auction: At $310 total for a used lens, I would rather pay $25 more and get a new copy of the smaller, lighter Sigma 28-70.)

So, what do users say about these lenses? Here's what Fred Miranda has:
  • Sigma 28-70: 7.8 overall rating for the "EX Aspherical," 8.5 for the "EX Aspherical DF." Of course, I have no idea what the difference is between those two. Both have reviews that go back to 2003, so I'm not sure which one is newer. For both versions, some user reviews say it is soft wide open - but HOW soft is "soft," ya know what I mean?
  • Sigma 24-70: 7.9 overall rating for the "EX Aspherical DG DF" version, which seems to be the more recent one.
  • Tamron 28-75: 8.7 overall rating, and a ton of reviews. But some reviews talk about getting and returning several copies before getting a "good" one - makes me worry about QC.

With all this stuff online, and my other post at DPR, why am I bugging you good people? Well, because I trust you all!

So, my questions are:
  1. Does anyone have experience with all three of these lenses?
  2. How about the AF speed? Any noticeable differences between these three?
  3. How sharp is each lens wide open? I plan to often use this wide open, so that sharpness wide open at f/2.8 matters to me.
  4. How does the sharpness/contrast of each compare to, say the DAL 55-300, or the 18-55? I'm generally happy with either of those lenses, even wide open, so use that as a benchmark.
  5. Does the Tamron have more "sample variation" issues than either of the Sigmas; i.e., should I stay away from buying used, and only buy new so I can return it if I get a "soft copy"?
  6. Has anyone ever bought any of these lenses used? Were you happy with what you got?
  7. Are market prices inflated right now? Does anyone expect them to drop back down again? I can be patient, and keep waiting and looking for a "deal." But I have been looking for a few months, now, and I don't think I've seen the Tamron for less than $300 since last summer. (I'm really regretting not getting the Tamron back then!) I'm not as sure about the price fluctuations of either of the Sigma lenses, because they only recently came under my radar.
  8. I'm very tempted to go with the Sigma 28-70, mostly because of the lower price and lighter weight. I don't need Pentax *-lens quality; as I said above, I'm generally happy with with the 18-55 and 55-300, even wide open. Would the Sigma 28-70 be at least as good, wide open at f/2.8?

Thank you, THANK YOU for your input!


04-29-2010, 12:24 PM   #2
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Greg, my only experience is with the Tamron, and in that regard I've not had to look any further - and it was my first copy.
Optically, a good copy is as good as you'll get for any lens. It's sharp throughout the focal length range and at all apertures.

It's comparable to any other lens I have, but certainly outdoing the kit 18-55 lens. The 55-300 is good but the 28-75 is in another league. What I could compare it with is the DA* 16-50, which the Tamron stacks up well to, but the 16-50 has the less tangible X-factor that adds vibrancy and life to images better IMO.
05-13-2010, 07:17 PM   #3
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I have the Sigma 24-70... got it used for $300... it's very sharp and wonderful indoors and in low light situations... hunts a bit in low light... but the sharpness is superb...
05-13-2010, 08:27 PM   #4
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I'm not sure you have the right specs on the 28-70. I just sold one it had a 77mm filter size and weighed a lot more than you have stated. It was constant 2.8 EX, this also interferred with on body flash. I was thinking along your lines intially when I got the Sigma, I sold it because I have now gone Pentax 17-70 SDM and A 50MM F2 for the low light. For me a better setup, I really missed the wide end, below 28, was looking at getting the 16-45 as well, went 17-70.

05-13-2010, 09:59 PM   #5
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QuoteOriginally posted by Cams Quote
I'm not sure you have the right specs on the 28-70. I just sold one it had a 77mm filter size and weighed a lot more than you have stated.
Sigma 28-70/2.8 EX DG has 67mm filter, 74mm X 87.2mm size, 510g weight

05-14-2010, 12:44 PM   #6
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I have the old 28-70mm f/2.8 EX DF (dual Focus ... kinda like quick shift).
it's the predecessor to the EX DG ... as far as I know the DF is Full Frame and the DG may be APS-C (but I think the DG has different Digital coatings on the elements).

If i was choosing ... I'd be going the Tamron 28-75mm f/2.8 ... I like my Sigma ... but I think the Tammy is a better lens.
05-14-2010, 07:31 PM   #7
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Like you, I was looking at those very same lenses and kicking myself in the butt for not buying them last year. I ended up with an F 35-70 Macro from the marketplace. Not as wide or as fast but so far I don't have single complaint with that lens and I saved myself a ton of money.
05-23-2010, 01:01 PM   #8
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I'm also torn between the sigma 24-70 and the tamron 28-75

I like the build, size and weight of Sigma's lenses - I have the 10-20mm EX DG and love the feel of it

But I stumbbled on a review Sigma 24-70 f2.8 EX DG Macro & Tamron 28-75 f2.8 XR Di Macro Photo Gallery by lightrules at that showed alot of IQ in favor of the tamron. So now i'm thinking, should I go for IQ or feel - will the IQ make a real difference - Am i totally nuts even thinking of going for the feel of a lens over IQ?

just my thoughts


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