need a little help bet tamron 17-50mm f2.8 or sigma 17-70mm ex

Im choosing bet tamron 17-50mm 2.8 and sigma 17-70mm ex 2.8 non hsm anyone had experience on this 2. i been reviewing a lot of post but nothing comparing the 2 head on.
also is will the 2.8 be a good upgrade to the 28-135 kit lens in terms of IQ or would it give just the same results. I use my camera mainly for family vac, my kid school activities, landscapes, disney, zoo stuff like that. just in terms of IQ sharpness? also from time to time portrait shots, fashion shoots for experience only not being paid!!!!

Both of those lenses will give you better IQ then the 28-135. I was debating on the same two lens, what made me go with tamron was the constant 2.8 unlike the sigma.

Also another thing to consider is that the sigma can do semi macro shots, you can get a lot closer with that then the tamron.

Sometimes with the tamron I find it too short, and wish i had the 70mm on the long end.

Leonid Photography wrote in post #11026340
Both of those lenses will give you better IQ then the 28-135. I was debating on the same two lens, what made me go with tamron was the constant 2.8 unlike the sigma.

Also another thing to consider is that the sigma can do semi macro shots, you can get a lot closer with that then the tamron.

Sometimes with the tamron I find it too short, and wish i had the 70mm on the long end.

thanks im still debating on this since having limited funds, im taking my time to get the one that fits my needs. my priority is sharpness even in low light. most of my current lens dont have that ability except my niftyfifty. again thanks

You are comparing different types of lenses btw, the Sigma you are looking at is not a constant f2.8 like the Tamron. You want to either check out the Sigma 18-50 macro f2.8 or the Sigma 17-50 f2.8 OS. The Tamron 17-50 and the Sigma 18-50 macro are very, very similar, with the Sigma having a bit better build quality but warmer tones. I believe the Tamron may have 2 years more warranty too.

Which Tamron 17-50 ? The non-VC version is supposed to be sharper than the VC version.

The new Sigma 17-50 OS is supposed to be very good, but is pricey. The 17-70 is a varaible aperture lens -f:2.8 at 17mm, f:4 at 70mm. I have the 17-70, but mine is in for calibration because of autofocus problems, so I can't comment on how good a properly working copy might be.

The non stabilized Tamron is supposed to be better than the new stabilized version.

I've been using the Tamron 17-50 f/2.8 now for almost 4 years as my main walkaround lens (first on my 30D and now on my 7D). I love this lens. IQ is outstanding and, even though it is not a USM lens, the focus is not too loud. Tamron also has the advantage of a 6 year warranty. I have never missed having stabilization on it (mine's the original non-stabilized version), so I'm not sure that's worth it. I've seen them going used for ~$350.

If you look at the 'Similar threads' section at the bottom of the page, you'll see that this has been discussed on many occasions. Lots of info in those threads

icassell wrote in post #11026691
I've been using the Tamron 17-50 f/2.8 now for almost 4 years as my main walkaround lens (first on my 30D and now on my 7D). I love this lens. IQ is outstanding and, even though it is not a USM lens, the focus is not too loud. Tamron also has the advantage of a 6 year warranty. I have never missed having stabilization on it (mine's the original non-stabilized version), so I'm not sure that's worth it. I've seen them going used for ~$350.

I also have the Tamron 17-50 2.8 - sharp lens, excellent value

icassell wrote in post #11026691
I've been using the Tamron 17-50 f/2.8 now for almost 4 years as my main walkaround lens (first on my 30D and now on my 7D). I love this lens. IQ is outstanding and, even though it is not a USM lens, the focus is not too loud. Tamron also has the advantage of a 6 year warranty. I have never missed having stabilization on it (mine's the original non-stabilized version), so I'm not sure that's worth it. I've seen them going used for ~$350.

+1 to the max...I got the 17-40L to replace my 18-55 and after trying out the Tammy, I was sold and replaced the 17-40L with it.