I can't seem to get the defocus node to work. I plugged in the depth output into the Z input, and checked "use Z buffer". With that enabled nothing happens when I mess around with any of the settings. Do I have to re-render the scene?
Hey Kent, I have the same issue - the depth information is certainly there in the .exr, I can see it with the help of a normalize node, but when plugged into a defocus node it either blurs everything without z-buffer or does nothing with it. I can't upload the screenshot for some reason but the settings I use are: F-stop @ 1 / Max blur @ 16 / Threshold @ 1 / Z-buffer ON. Blender 2.79
The defocus node + z-depth pass works a bit differently for .exr - which I failed to cover in the depth of field lesson 😞
With .exr the User Z-Buffer option is disabled because that's only relevant to the raw render data from a 3D scene, not the data converted to .exr. I just tested that it still works, so here's a screenshot of a simple setup: