28-135 Replacement Recommendations

I have a 28-135 IS that I've had around for a year or so. It's generally my walk-around lens. However, for the past several months I've been increasingly disapointed with the quality of my shots with it. The IS doesn't seem to be helping, the focus is off more often than not, etc. Plus, I have a new 100-400L and comparing shots with it and the old 28-135 is like night and day. Granted one is an L and the other isn't, but that doesn't make me forgive the poor quality any easier.

So, my question is, should I replace the 28-135 or try to get it serviced? Maybe it's a problem with this particular lens that can be fixed and not a general 28-135 issue. Or, if I do replace it, what is comparable to the range it has with better sharpness, color, etc.?

Thoughts, ideas, or suggestions?

The key is your budget here. I agree with you on the 28-135 IS which I owned and quickly sold.

The obvious direct replacement standard zooms are the Sigma and Canon 24-70 2.8's and the Tamron 28-75 2.8. The Tamron is cheaper and lighter, the Sigma is an extra 40% or so heavier, better build and a little bit more expensive, and the Canon is heavier still and at least 3 x the price. Image quality is very close. Build and USM motor of the Canon very good. Build and motors on the other two perfectly acceptable. There are comparisons of these three if you search here and at fredmiranda.com ...

I chose the Sigma after having also owned the Tamron (which was good) and I've been delighted with it. Personally, I'll soon be getting a 100-400mm IS L or 300mm IS L and I want all my lenses to produce similar results direct from the camera. I know that the Sigma will not let me down.

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