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12-10-2011, 12:49 AM   #1
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Sigma 24-70 vs Tamron 28-75 (particularly at f2.8)

Hi guys,

Sorry if this topic has been covered but I specifically want to talk about the performance of these two (the OLDER, non HSM Sigma 24-70 f2.8 EX, and the Tamron 28-75 f2.8) WHEN they are at f2.8.

I already have the Tamron - the guy I bought it from said it's pin sharp at f3.5 and slower, but not QUITE that sharp at f2.8 - I haven't really done any studio type tests yet but I can see what he means a bit, just a bit of fuzz around the focussed area at f2.8. I have the Sigma coming soon so if I get time I might line some tests up then. The reason I am so interested, is that I'm doing my first wedding at the end of January and will be using one of the two, but will obviously go with the one that is sharper at f2.8. This isn't just because of low light (though that's obviously a concern) but because generally, the wider open a lens can be used, the more I want it, because I love O.O.F. backgrounds.

So yeah I am just wondering, before I spend half a day doing tests and analysing 100% crops, if anyone has figured out which they prefer to use wide open, before?

Other factors are that I find the Tamron to be light enough for a fast zoom, and I'd prefer to have the 5mm at the long end than the 4mm at the wide end.
Thanks guys.

12-10-2011, 02:14 AM   #2
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The Tamron should have the edge of sharpness but I suspect QC variations have much greater impact on these zooms. Getting a properly aligned one with accurate AF will require quite a bit of luck. They aren't well made to being with unfortunately.
12-10-2011, 02:55 AM   #3
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The guy who sold me my Tamron said he sent it to Tamron about a year ago to have the AF calibrated, and I've done a few shoots with it now and have not noticed any obvious OOFness, so I guess that's good.
We'll see how the Sigma goes.
12-10-2011, 06:25 AM   #4
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They are about the same sharpness, oh may be i like the tamron better, or may be due to it's size that i shoot more with the tamron.
I have both, but never tried compare these two optically. The tamron is lighter, smaller and it wins.

About the wide end, i use da12-24 or the sigma 8-16 at16mm.
75mm at the long end is too short for me, and i always have a macro 90 or 100 or 105 to cover AF.

Lots of compromize for both zoom for me.

12-10-2011, 07:29 AM   #5
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I have the sigma, and it is excellent for indoor event photography, especially when used with Flash. I usually shoot at F4 or higher, not due to sharpness issues, but more for depth of field when taking photos of 2-5 people together. I work with canon folks using their 24-70L, and I can tell you that my sigma doesn't come close wide open, for what it's worth.

Tamrons are sharp. I don't own the 28-70, but do have the 70-200 and it is extremely sharp, even wide open. I second the notion that there is a wide variety from lens to lens when looking at old 3rd party lenses. But as we know, there's more to image quality than sharpness. It really depends on your needs; the sigma suits mine well because:

1) When I'm at an event, it's large size (82 mm filter BTW) isn't a big deal. You know you're going to be carrying heavy kit(s)
2) One thing it's impressed me with is focusing accurately in low-light situations; I've used on 3 bodies by now
3) It seems to work incredibly well with flash indoors, may be my luck but I find it accurate in exposure.
4) The extra length at the short end is important to me . . . 4mm at the short has a lot more impact than 5mm at the long.

I will say that I don't grab this lens, even though it's an ideal focal length for me when I'm running out of the house. Why? Just too big, heavy and bulky.

Personally, I'd look at the Tamron 17-50. Seems to have great reviews, is well priced and can be purchased new so there's some quality assurance (at least you can return). Hope that helps.
12-10-2011, 07:36 AM   #6
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The Tamron is sharper in the center at 28 while the Sigma is sharper on the edges at 24. This is true at 50mm, and then at 70mm the Sigma is better at both the center and edge wide open.

Stopped down, the Sigma is still sharper in each range.
12-10-2011, 05:04 PM   #7
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QuoteOriginally posted by Rude Quote
Personally, I'd look at the Tamron 17-50. Seems to have great reviews, is well priced and can be purchased new so there's some quality assurance (at least you can return). Hope that helps.
Thanks but I didn't say I wanted that range... I am talking about a wedding and if anything the Tamron 28-75 I have is too short (one of the first replies said that, and I agree) - I'd really like a sort of 45-100 f2.8 but I don't have one and I am not going to buy one (the DA 50-135) for now.

For the wider range, I have the DA16-45mm so I don't need a 17-50, ok yeah a stop faster but I'm not going to be using f2.8 at anything wider than 40mm.

Well thanks guys - I'll do a few tests myself and if I find (like I think I will) that the Sigma is not worth the size or the loss of 5mm at the long end, expect to see it sale on here!
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