another "what lens" question

[Herrmann]

i am thinking about buying a second hand lens. my choice would be standard length from 17/18mm
i found three within my modest budget and i cannot make my mind.
which out of those three would you choose?

1. Sigma 18-50mm f2.8 EX
   
2. Sigma 17-70mm f/2.8-4.5 DC Macro
   
3. Canon EF-S 17-85mm f4-5.6 IS USM

what would be your reasons?
have you used any of those?

thanks for your help

 

[Hyster]

Have you considered the Tamron SP AF 17-50mm f/2.8, I had one of those and it was a belter of a lens for the money.

 

[woof woof]

Of those I'd go for the 18-50mm f2.8.

I have the similar Tamron 17-50mm f2.8 and that replaced my Canon 17-85mm. The Canon lens has a good zoom range, IS and USM but no constant f2.8 and high distortion at the wide end of the zoom.

If you're not too bothered about the wide end distortion I think that the Canon could maybe be a good buy. Reviewers say that it displays lens adorations but in use I never noticed anything too bad and I think that apart from the wide end distortion you'd have to pixel peep excessively to pick fault with the lens and the USM and IS are very nice, no constant f2.8 though.

I have used the Sigma 17-70mm but discounted it as I wanted a constant f2.8 and the max aperture of the 17-70 only lasts until you only fractionally move the zoom ring. It gets good review though and has many fans but I'd still go for the constant f2.8.

 

[The Matt]

I can't really fault the tamron 17-50 2.8. I forget why I chose that over the sigma 18-50 but I'm certain there was a good reason for it.

 

[Herrmann]

after reading all reviews and opinions i've decided to save some more cash and go for tamron 17-50mm which should be delivered tomorrow.
thanks for the advice