18-135 UD vs 28-135 USM

[buzzrk]

I have decided to buy midzoom lens for my T2i.
But I am not sure if I buy USM lens or the UD lens.

Ken Rockwell says he likes 28-135 USM a lot.
Canon 28-135mm IS

But I am noticing more of UD lens being packages in kits instead of USM.
This is probably because most entry level cameras are not full frame.
I have a T2i myself so 28mm will not give me wide angle shots.
But that might be okay because I do not shoot very wide angle shots.
I shoot landscapes but just as a tourist.
Do you guys find 28mm inadequate on crop sensor?

Which lens is better?
Does UD lens have focusing that is comparable to USM?

Another factor is that USM lenses are available as used because they got them with kits.
Not many people are selling UD lens.

[frydham]

I have the 28-135, it's great lens, but sadly it's full of dust.

You should this review:

Amazon.com: mhnstr's review of Canon EF 28-135mm f/3.5-5.6 IS USM Standar...

[asoupley]

I have the 18-135 on my T1i... I love the lens. Before I bought it, I too struggled with the 18-135 vs 28-135 decision. I made my decision because of the crop factor and figuring I would not use USM all that much. That being said, I sort of wish I would have gone with the 28-135... I find that I rarely shoot lower than 28 on my lens, and it gets frustrating not having USM. One advantage though is that the 18-135 is a newer lens, and I believe it has a newer generation of IS.

Hope that helps
-Soup

[buzzrk]

The reviews on 28-135 USM are not very good.
People use it because they got it in kit.
It has some oom creep and I heard some complaints about how loose it is and dust issues.
So I might just hold on to my 18-55 little longer until I can save enough to buy again.

[Raoul Isidro]

I have the 18-135mm EF-s lens and use it on the 7D. I have another similar lens I use as a back up which is the 17-85 EF-s USM which is also very good.
I have the 28-135mm EF USM and use it on the 5D2.
All three lenses have their respective unique merits, and only by using them for so long will their shining qualities come out.
18-135 and 17-85 is a great all around lens. 17-85 for extended outdoors because it is lighter and smaller.
28-135 only use for the Full Frame 5D2.
All three lenses have IS.