I bumped my EX1 pretty hard the other day and it affected the focus, but only on infinity. In other words I can focus on anything just short of infinity, but when I'm zoomed in all the way on really distant objects, they just stay slightly out of focus, with the ring forward or back it doesn't matter. I ran the auto back focus setup a couple of times, but nothing changed. If anyone has any suggestions, let me know, otherwise I'm taking it to the Sony Service Center on Monday.

Make sure the glass isn't loose, i know someone else who did the same thing (cough cough) and had exactly the same symptoms, the person only realised that the glass was loose when he turned the camera upside down and heard a rattling.
If the glass is loose then remove the lens hood and turn the lock ring with your thumbs.

Paul.

Paul,
Thank you so much. I tightened the lens ring and the focus is perfect now. I'm really glad there's a forum like this.

Glad to have helped.

Paul.