canon 55-250 IS blur edge, anyone?

jongpl wrote:

That seems to be quite sharp. I got a few sharp picture just like
yours but most of the others have the blur edge problem, I did try to
shoot a flat plane and it seems ok.

Well, if you really get sharp pictures on flat objects, then there is some other problem. A decentered lens should always to be unsharp on one side, not sometimes ok, and sometimes not.
Assuming the lens per se is sharp, I can only see two points.

• Some problem with the IS. As I said, it's a moving element, something is not quite right with it, it's decentering?

• A problem in how you take pictures. IS cannot remove rotational movement of the camera. If you press the shutter button sharply, you give sort of rotational movement to one side of the camera.

Now, I think the sigma lens is probably quite a bit heavier, heavier lenses are usually more stable, the 55-250 is quite light. That could explain perhaps the difference, why you see less problems with the sigma.

Did you ever try tripod pictures to eliminate shake as a problem?

If not, you could try shooting with mirror up/self-timer, to get around the "pressing the shutter button" movement.

I must say that the blurry edge tree picture does look somewhat like motion blur, perhaps indeed and IS or handshake problem?

BTW I am using 350D which seems to be the problematic camera for this
lens according to photozone. But I have read that many 350D users
sell thier sigma for the canon and they are happy for it. Ya, I think
I should send it back to canon.

I guess you can improve it a bit by using center AF point only.

I only use center AF on the 400D as well. Otherwise many times, some of the other points bring the focus to things in the foreground, causing unsharp pictures.

Regards
Kiamsoon