Get cameraDepthBuffer wihtout rendertarget?

Hi,
Is there a way to get the game-camera’s depth buffer, without having to make a new camera and rendertarget?

Translucent materials and post process materials also have access to the depth buffer.

to be specific, I want to access the pixels data on the cpu. You can do that with a rendertarget, but it is unideal/inefficient to render one just to get the game-camera’s zbuffer.