Fastest way to render depth only

[genesys]

What's the fastest way to render out ONLY CGeometry_ZDepth for a sequence? preferrably without changing the materials in the scene. Is there an easy way to deactivate all lighting computation and all shading alltogether and only output CGeometry_ZDepth of primary rays?

[TomG]

"Render only masks (disable shading" in the Scene tab of the Render Setup.

[sebastian___]

Isn't even faster to use the scanline renderer for that ?

[TomG]

Shouldn't be any faster or slower - with the Only Masks option, there is no actual rendering taking place anyway.