Repared lens blurry

[jimmclean]

A couple of months ago I had the image stabiliser on my Canon 100-400 USM lens replaced (and my sensor cleaned). Since then, I haven't managed to take a single really sharp photo. Does anyone know whether it's possible that something could have happened to the lens, or is it just my poor technique? I have tried cleaning the lens, so it's not that.

[deshojo]

You need to test the lens in stable conditions, ie. preferably tripod mounted, or at least resting on a bean bag or similar.

If you were getting sharp photos before in similar circumstances, then it is most likely that something went wrong with the lens's reassembly and you should send it back to Canon.

Complicated lenses like this have very fine tolerances, and it is easy for one element to be slight misaligned (or even for the replacement IS unit to be faulty). I have heard of other people who's lenses came back worse after service or repair.

[mike from ebbw]

put the camera and lens on a table/wall,somewhere really firm.focus on something and set the self timer button.you know then that there is no interference at all and the shot should be pin sharp.if not there must be something wrong with the lens.