Mk II N - AE-lock AF button issue?

I've just received a 2nd-hand 1D mk II N to act as a second body to my mk3.

I've cleared all of the custom and personal functions and then tried to set the AF to the AE-lock button (CF-04)

The behaviour of the camera seems very odd - and I'm wondering if I've bought a damaged unit. It seems as if the AE-lock button sticks on (electrically, that is - not physically)

With AF assigned to the AE-lock button and in single-shot mode, the camera will acquire focus on the first press but will not refocus on subsequent presses. This happens with both the portrait and vertical-grip AE-lock buttons.

In servo-mode, I can see the distance-meter on the lens chattering away after I have removed my finger from the AE-lock button. It should stop trying to AF immediately that the button is released, no?

With AF assigned to the normal shutter button, all is well.

The other telltale is that when I use the +/- buttons to zoom in playback mode (i.e. AE-lock and AF-point select), as soon as I press the '-' (AE-lock) button, the image zooms out continuously (rather than in one increment per button press).

Can someone who owns a 1D mk2 N please confirm that this is *not* the way it should work - i.e. it's not some whacko C-FN or firmware (current is 1.1.2) issue.

Darn-it. I'd hate to have to return the damned thing (bought via the internet from an online shop - 7-day no-quibble return and 3-6 months warranty) - or chase Canon for an (expensive) fix...

Without wishing to anger the Goderators with a bounce, I'm off to bed shortly and *would* like to know if anyone else has encountered this problem before - and whether it's a big fix or a little one (if such a thing exists with Canon flat-fee servicing...)

I've done some more tests - definitely looks like a fault.

1.) If I put my 300mm f/2.8 on the camera and set the lens button to AF-Stop, it tries valiantly to override the * button (you can tell when it is locked-on in single-shot mode by looking at the green focus-blob in the viewfinder).

2.) If you focus and then quickly turn the camera off and on again, it will try to focus on its own (without pressing any buttons) for a fraction of a second after powering back on.

My gut-feeling is to return it for a refund and to keep my eye out over the winter for another one.

Yeah I've never had it act like that. I'd say there's something amiss.

Thanks - it went back to base yesterday. The camera had apparently been checked by Canon two weeks ago - but I concede it'd be an easy function to overlook (the normal AE-lock button-functionality is 'latching'...)

Anyway, the company (very decent to deal with) picked the thing up by courier and have given me a full refund. They're sending it back to Canon for a fix and have given me first refusal when it comes back.

I couldn't really ask for more. With luck I should end up with a fully-serviced body with nothing to worry about. Well done to the company that sold it to me.

You definitely had a sticking AF button. It is good you had honarable people you are dealing with in your purchase that will give you your money back.

Yeah - it wasn't a sticking button as-such - otherwise you'd expect the vertical-grip version to work fine - but both had the same problem. Anyway, my gut-feeling is that I've found some good-guys* and will ultimately end up a happy-bunny.

*they do exist...