Just recently my trusty 70-200 f/2.8 IS autofocus cannot lock on a subject that is JUST beyond the minimal focal distance regardless of aperture.

For example, with my 1DSMK2 on all point AF/single shot, I am standing in my backyard and at 200mm and f/2.8 I aim at my fence which is 3 meters away. The autofocus will move "in and out" trying to acquire focus lock and never does. I can lock focus myself on the fence, but when I half press the shutter to get AF to work the focus is then lost.

Tried it at 70, 100 and 135 and f/4.0, f/5.6 and f/8.0 with the same result.

Tried it with 1.4m and 2.5m minimal focus distance and get the same result.

Tried it with just center AF point and still nothing.

I then change subjects to my neighbors chimney which is 10m away and the lens locks focus instantly.

Has anyone ever had this happen to them?

Also repeated all tests on my 20D and with my 24-105 on my 1DSMK2 to rule out body AF errors.

Just wanted to ask before I send this thing to Irvine for a checkup.

I have always had problems with my 70-200 thing pisses me off all the time. I feel your pain. Mine is going back next week.
Doug

Tried the focus limit switch?

Yup. Tried both focus limits to no prevail.

And to think it took this picture last week at 2 meters.

Wow, never had that problem with mine!

E

Mine works fine, too. Are you sure the camera is set for the AF points that you think it's set for?

Yes, the AF points work fine.

Tried my 24-105, 35L and 17-40 and all work as expected on both of my cameras.

The 70-200 shows the same focus hunting on my 1Ds Mark II and 20D.