Depth of field is not being rendered in Blender Internal I have quite an annoying thing, that I don't know how to do.
I'm about to render a small clip, but I don't know how to enable Depth of Field in animations render to make it visible in the final product. It is visible in 3D view, but not in the render. Any help will be appreciated.

Edit: I use the in-built renderer, nothing special. I'm not using compositor.
You need to use the compositor :)

The Camera settings sets an object as your focus point and the Defocus node uses this for calculations. Or, leave it blank and use the Defocus node settings for distance calculations.

In the Render layers settings, ensure you've added a Z pass.