1DS MKII Auto Focus Problem

[Dredd123]

Hi All,



I recently bought a used 1DS MKII. The camera is in fantastic shape with a low shutter count (approx 23K) and one careful owner.



Unfortunately, the camera seems to be exhibiting an auto focus problem, but the problem only seems to happen when the "primary" shutter button is used. When the "secondary" shutter button is used (the one which is there for when you are holding the camera in portrait mode), auto focus works perfectly (it's very quick and very accurate). However, when the primary shutter button is used, autofocus is either VERY tardy (like it can take two or three seconds before the lens focuses), or it just doesn't auto focus at all. I know it's not the lens because it happens on more than one lens, lenses which work perfectly on my other camera bodies.



I'm wondering if there is something wrong with the shutter button? Any other ideas?



Thanks in advance,

Dave.

 

[Dredd123]

I used a custom function to change the auto focus button to the * button and found that auto focus works perfectly when assigned to the * button. Therefore, I reckon it must be something physically wrong with the primary shutter button.