Jan Sichermann +++ Maya Zdepth in After Effects

Maya Zdepth in After Effects as Depth of Field

To begin, let me say that it is certainly possible to render out Depth of Field out of maya directly. However this takes a long time to render, and you never know if your camera settings are correct until your render is done. This is a great alternative.

As an example I set up a simple maya scene.

Now in our Render Layer Editor (Windows -> Rendering Editors -> Render Layer Editor) make a new layer containing all the objects, excluding the lights.

Rightclick on this layer and choose from presets -> luminance depth [image to the right].

Now when you render this layer, you should get a clean zdepth image ranging from white closest to the camera, to black furthest away from the camera.

In addition to this I rendered the actual layer by selecting the masterLayer or creating another beauty layer.

Now import both layers into After Effects and pull them into the timeline, putting your luminance depth layer under your color layer.

You can now rightclick or select and choose Effect -> Blur & Sharpen -> Lens Blur from the menu.

In your effects options, you can now define your luminance render as a depth map layer.

Now play with your Blur Focal Distance and tweak other settings to get your desired Depth of Field result.

This can, of course, be done to a rendered sequence instead of an image - making your rendering time more efficient.
You can also utilize this in Photoshop by copying your rendered luminance image into the alpha channel of your color render and applying a Lens Blur to it.