Hi all, I recently acquiried a 24-105mm and noticed that whilst yes, it is admirably sharp in the centre, and not too far behind in the corners (1,6x crop), that it exhibits a curved plane of focus between about 24 and 35mm. For exampel, at 24mm (1,6x crop)with a target distance on about 65 cm (25 inch), the corners only come in to focus at about 70 cm (27 inch) whereas the centre isin focus at 65 cm(I used live view 10x maginfy to confirm during shooting and reviewed on the computer). Before I send it back to Canon, I was wondering if someone can tell me if this is actually unusual or a normal trait of this type of lens which wouldn't be covered by thewarranty (or if I should do any more testing). I don't have access to a full frame body for additional testing, but can put up the testphotos if it helps.

Thanks in advance, Ingenting.