I bought a canon 50-250mm IS lens (for my T1i), maybe two years ago and haven't used it much, but whenever I do, I always regret using it. Pictures are blurry, the depth of field too shallow and so on. Here's an example:
I shot this one in auto mode, and it is awful. I can definitely see that some of the blur is from handshake, but the surrounding is extremely blurry. Is my lens broken or is this normal?
I am still learning about photography, and did get a much better shot, but I had to hop on a boat and get much closer.
Answer
There is definitely something very wrong here. That's not a focus or DOF issue, but looks like the lens suffers from extremely strong field curvature.
It's normal for a lens to be sharper in the center than around the edges, and this effect gets stronger with wide open aperture and at the extreme ends of the zoom range (your last sentence indicates that you get sharper images when you zoom in less). But it should never be as extreme as what is visible on your picture, at least not in a lens produced later than 1900.
I can't think of any way that user error could produce this result. It definitely looks to me as if that lens is broken, i.e. has a strongly decentered lens element. You should have sent it back right after you bought it, but you should contact Canon's service department in any case; hopefully they will still fix it - maybe not for free, but decentered elements are usually not the "broken beyond repair" kind of problem.
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