Most 24 volt AC cameras have three power connections. Using AC power requires connection; an input and return, but not the ground. Making a input/ground connection can result in damaging either the power supply or the camera or both.
Auto Iris camera lens are either video or D.C. driven. The drive from the camera must match the type of lens being used. Most cameras will have a physical switch changing the setting between Video and D.C. drive.On some cameras this switch is located inside the camera.
Cameras and lens can be either C or CS mount. Most cameras today are CS mount. Using a C mount lens on a CS mount camera will require using a C mount adapter which is a 5mm spacer. Most lens and/or camera manufacturers provide this type of adapter. Mis-matching the lens, camera and adapter will make it impossible to focus a lens.