Focus Issue Advice Needed

Hi folks,

Just got a 5d MK III and never noticed an issue with some lenses on my previous 5D II nor !D MK III. Both are now sold, so I cannot test. But let me describe the issue and maybe it was always there and I never noticed or its a lens or a body issue:

Take my 100 F/2.8 L macro. I have focus set to back button, by the way. So if focus is ANYWHERE close, hit back buttton and it latches onto focus. BUT, if I rack the focus ring all the way to the right then hit focus, it does not even try to grab focus. Regardless of which range is selected on the lens. Or what distance away my target is. As a matter fo fact, does not even have to be racked all the way, just down to 3 ' seems to be enough.

Seems to happen with 70-200 and 70-300 as well. 24-70 is fine as well as 50 mm. Have not tried any of the others.

Am I forgetting something? This can't be normal, can it?

Appreciate your replies.

Most likely:

Normal. It's a custom function 'lens drive when AF impossible' needs to be 'on' or 'yes'.

At least that's what it sounds like to me.

Here's the relevant info from the manual:

On my way to check this. IO somehow recall that was only for some longer lenses, but maybe I misremeber. Will see in moments.

I can tell you I just tried all 7 lenses and this only happens on two of them - 100 L and 70-300 L and that on only at 300 and if set to infinity or close.

Back in a few to see if that setting is the fix.

Thanks.

Wow. That was it. Thanks!

Makes me wonder why I would ever set it not to continue to focus.

I feel much better right now I was a bit concerned.

Different lenses have a different minimum focusing distance. So, depending on how close you are to the subject some lenses may autofocus while others wont.

Understood Dan. I was testing the issue at a good distance to be sure that was not it. I think what got me is Canon changed the default setting. Used to be ON and now is Off. Unless I had changed it and did not realize.

At any rate, all working as expected now.