Issues with camera functionality when lens is attached.
I have a Canon Mark 1 EOS-1 Ds (released in 2002). All the camera's functionality is operable. Menus, displays, buttons, all work correctly. However when I attach a lens much of the cameras functionality stops. Auto-focus does not work and display stops working, but can still release the shutter and focus manually. Can change Aperture/Shutter speed, but those are the only two settings that can be adjusted when a lens is attached.
So for example, with a EF lens off the camera, I can review the menus, and pictures taken, change ALL The settings (Shooting Mode, Drive, White balance, ISO, Auto focus points, ETC.) When I attach a lens (So far any EF lens I have put on it) I can take pictures and adjust Aperture/Shutter speed (The Two Dials) but nothing else functions. I will note that the Depth of Field button (Lower left under lens ring) seems locked or unable to be depressed. Also, Auto-focus and the light meter don't work. No Error messages also.
I feel like this may be an issue with the In-Camera Contacts for the lens. I can see where the contacts are there are two screws on either side for that piece to be removed, but I'm not sure how connected everything is there.
Such a weird issue that functionality shuts down when a lens is attached, has anyone heard of this, or have any experience with repairing the lens contacts in the camera?