which walkaround lens for a 20D

I've been looking for a good upgrade from the kit lens to walk around the city with. I've narrowed it down to three choices:
the sigma 17-70
the tamron 17-50
and canon's 17-85 IS


I've heard that the sigma and tamron are both excellent optically, maybe the tamron being a bit better in the sharpness while wide open. I doubt I would be shooting wide open often, so this might not be a problem, but you never know. I would prefer the extra range of the sigma and canon, but optical quality is most important. I've heard the Canon IS is not as good as the other two optically, but the IS is attractive for handheld dusk/night shots, and I already have the 50/1.8 for low light, so f/2.8 is not necessary.

I'll be using the lens as a walkaround in Manhattan (hopefully going to get into some night stuff, in which IS would be ideal), and maybe some portrait work, so the tamron would be better for that (but again I have the nifty fifty which is serving me well for that right now). I just need to be sure that the lens is the best possible optical quality for the price range.

Which would you recommend?
Thanks a bunch.

Tamron 17-50 for the best optic of your choices, and it's constant f/2.8 is great.

I use the Sigma as my walkaround on my 20D and it works great. Almost never leaves my camera.

gregjp48 wrote in post #4859587
the sigma 17-70
the tamron 17-50
and canon's 17-85 IS
Which would you recommend?

If you want a fast lens, then the Tamron. If you want anything else, I recommend you take a hard look at the Sigma 18-200 OS (over the 17-85 IS).

so we have 1 vote for a tamron, 1 for a sigma, and 1 for tamron if i want a fast lens.

i don't like the 6.3 at the end of the 18-200OS. I'd take 5.6, but 6.3 is a bit overdoing it. Plus I've seen a lot of reviews that say it's soft. Have you had a different experience with it?

tamron 17-50

AiGTs wrote in post #4859878
tamron 17-50

is there a reason? speed? are the optics better?

Honestly, I've never had a better walkaround than my 30mm. Perfect FOV, excellent color and sharpness, and very lightweight.

I love my sigma 17-70 I have used the Canon 17-85 and was not the impressed with the IQ, but it was on two different bodies (XTi and 20D).

gregjp48 wrote in post #4860710
is there a reason? speed? are the optics better?

Yes, it's a constant 2.8 and generally considered to be very sharp for its class.

gregjp48 wrote in post #4860710
is there a reason? speed? are the optics better?

I was considering the Tamron before I got my 17-55 IS(I shoot in poor lighting quite often so I need the IS). The range of the Tamron is perfect for general purpose photography and the constant 2.8 is definitely nice. I've only heard good things about the Tamron, so I think it's the best choice out of the 3 you're considering.

Tamron.

gregjp48 wrote in post #4859739
i don't like the 6.3 at the end of the 18-200OS. I'd take 5.6, but 6.3 is a bit overdoing it

I don't see how the 1785 IS is a better option than the 18-200 OS. The Sigma is faster than the Canon at every comparable FL, plus you get 85-200mm as a "bonus". And FWIW, the OS lens is quite sharp at 200mm wide open http://www.pbase.com …s/image/8298503​8/original [extreme borders are softer than any of the lenses shown in this comparison though; but center performance is almost stunning.]

Some more links to peruse:
http://www.popphoto.co​m …00mm-f35-63-dc-os-af.html
http://www.ephotozine.​com …a-18-200mm-f35-63-DC-OS-1
http://forums.dpreview​.com …rum=1031&messag​e=24410116
http://www.fredmiranda​.com …owproduct.php?p​roduct=332
http://www.amazon.com …ySubmissionDate​Descending
http://www.pbase.com/l​ightrules/1785isv18200​os
http://www.pbase.com/l​ightrules/evfzz
http://www.pbase.com/l​ightrules/norcalpics

angryhampster wrote in post #4860768
Honestly, I've never had a better walkaround than my 30mm. Perfect FOV, excellent color and sharpness, and very lightweight.

You can certainly make a case for this one.

i'll look into the 18-200 and the 30 f/1.4

for the superzoom is concerned i'll have to do more research, but the speed of the tamron is looking better and better, though IS could potentially make up for it since I don't shoot sports or anything moving in low light.
as far as the prime, i'm a little concerned with having one focal length for city architecture and walkaround stuff, simply because i can't levitate off the ground or melt into it to change framing, whereas i can walk forwards and backwards with a prime when taking pictures of things on ground level. I think I might be better off with a zoom b/c of convenience. No doubt the 30 takes some GORGEOUS pictures though, and I'd love the speed, but realistically 2.8 might be all I need, since I already have the 50, and range is more important for me for this lens. I do always have the kit along too though... so the 30 might be a good choice if I have the kit in case I need a bit more reach. I really need a good decently wide lens though, and the 30 would be a bit too normal.

so I'm thinking the tamron, also b/c of the optics and speed that i can use in other situations. I could always get the 30 later (though I'll already have the tamron with that focal length in its range), and maybe a 10-22, but now i'm getting ahead of myself

Edit: Oh yeah how do the color of these lenses compare?
I know the color of the 30 is excellent as far as I can tell. How's the color of the tamron, sigma, canon, and other sigma?

If you are sure you don't need the f 2.8 I would suggest the Canon 17-85 IS. Who couldn't use IS? And you say you want the length.