This is video shows how to get an anti-aliased depth pass suitable for animation from Blender for After Effects. This allows you to then have control over the DOF (depth of field) in post production in After Effects for more control. This is a "raw" linear workflow where the DOF is not baked in from Blender and you always have full control.
Hope this solves some problems for some of you. There is a lot of conflicting information out there for depth passes from Blender. These usually show you how to make a depth pass that is either not anti-aliased or made for still images that do not work for animations.