This is the lens I may try. I think I'll rent it first...my 17-70 is not OS, I bought before the OS came out, but it's sharp.
>- 10-20 3.5 HSM >(http://www.sigmaphoto.com/shop/10-20mm-f35-ex-dc-hsm-sigma#. >Wanted a super wide for my D5100's DX sensor and was in doubt >between this and the Tokina 11-16 2.8. #well, there's also the >Nikkor 10-24 and I probably should have bought it# The Tokina >is well known for being really good and pretty sharp. It is >said to be better than this Sigma. And it is 2.8. But does not >have a built-in motor so it wouldn't auto-focus on my body. I >think Tokina announced a new model with a motor but there's >nothing on the shelves yet. >This one I don't like too much. I don't know. At least my copy >doesn't produce sharp images. Well, it can if I use the sweet >spot of 8 or 11 f/stop #above 5.6 is already better) but the >overall sense I have is that the image quality is poor. > >The first 2 are really good. > >>Danny - what Sigma Lenses are you using? >>I have a 17-70 which I love and I may try another. >>I was curious what you use and like. >> >