I've just received a replacement for my 24-70 f/2.8L II as after some shooting with the old one I felt it had some decentering issues (whole right edge was blurred).
The replacement seems generally sharper across the frame, though doing a brick wall test this weekend just gone I now believe this copy to have a slight blurry left edge, not as bad as last copy but still
The right edge is pretty sharp. On this point can someone tell me if decentering issues can be fixed by Canon repair centers?
The other issue which is weird is a strange noise/sound when I zoom in and out. The old copy I had was fine..a bit more resistance than this new one but sounded normal. The new copy I've got makes a strange tiny 'crackling' sound. It doesn't sound mechanical at all and the zoom action is smooth all the way. Maybe something to do with rubber seal in the zoom ring or air/bubbles in lubrication maybe? Only way I can describe it is the sound kelloggs rice krispies make when they 'snap, crackle and pop'
It seems to be quite random too. Sometimes it's worse than other times (temperature?). If I've not used it for a good few hours it hardly does it but then seems to happen more as I use it for that session. It is quite faint in sound I must add. If you were outside in noise you'd never notice but in a dead quiet room you can just hear it from behind the camera and if you put your ear to it it's clearly noticeable. I fear that if I used it for video the mic may pick it up easily causing some peaks in the audio.
Anyone else experience similar?