Curved plane of focus with 24-105?

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.

I do know that wider lenses do have a curved plane of focus and wider aperture lenses do to. It

HiIngenting, and welcome to the TDP Forums!


I'd suggest sending the lens into Canon. Although the 24-70mm f/2.8L reportedly has noticeable field curvature, it's not reportedly a 'feature' of the 24-105mm f/4L. Even with the 24-70mm, using the lens on a 1.6x crop body eliminates most, if not all, of the problem.


Personally, with my 24-105mm on my 7D, I don't notice any field curvature. With the lens on my 5DII, I also don't see any flield curvature - it might be there, slightly, but if so it's masked by the corner softness when shooting with that lens at 24mm wide open on FF.

Thanks for the replies. I took your advice, and ended with a new (exchanged) lenswhich seems to be much better. Certainly much more what I expect a <span style="color: #ff0000;"]L <span style="color: #000000;"]lens to be. [:)]