Sigma 10-20 on 7D vs Canon 17-40 on 5DMKIII

Timberland wrote:

I have a Sigma 10-20 that I've been using since 2007. A nice lens that I use for city photography and landscape shots. It's a lens I use on my 7D (that I still own).
This year I bought a 5DMKIII body (very nice). My widest lens on that body is a 24-105L (which I really like).
Now I have the opportunity to buy a Canon 17-40 lens in almost new condition for €450,-.
I prefer the image output of my 5DMKIII compared to the 7D. The 17-40 doesn't have the best reviews (soft corners).
I'm going on a trip to Peru, Bolivia and New York in about a month and I'm not sure what to do. Sell the Sigma 10-20 and get the 17-40 or simply keep the Sigma on my 7D (I do have to take 2 bodies on that trip besides other lenses).

Any advice?

Tim

I own the Sigma 10-20 f4-5.6 - I've been using it about as long as you yours. I love it.

I recently purchased a 6D. Of course, since I shoot interiors I needed to replace my 10-20 right away if I'm going to use the 6D! So, after contemplating the Tokina 16-28 and Sigma 12-24, I got the EF 17-40.

It rocks. I'm really, really surprised at how sharp this thing is. It's certainly superior to the Sigma. It's pretty good on my 60D as well - but I'd still suggest APS-C folks go with a 17-55 or Sigma 17-50.

But on an FF it's way sharper than my 24-105 - a bit of a shock actually.

I see you got the 17-40 (now), I think you'll be happy. I had uploaded some comparison shots for naught! Guess I should pay closer attention!