The ZDefocus node

…The z-defocus node is used to calculate…depth-of-field blurs, and requires a depth channel.…It calculates the amount of blur based on…the depth channel information, combined with your node settings.…It can be used for both CG renders and live-action plates.…I have a CG-rendered jet here, and it has a depth z-channel, which…I can put into the viewer's output channel, and show you that right here.…Critical issue about these depth channels, they must not be anti-aliased.…

Let me gain up the viewer a bit.…So here's my depth z-channel as rendered in Nuke, which does it correctly.…So does render man.…Many CG renderers do not let me put in the alpha channel,…and you can see there's plenty of anti-aliasing in the alpha channel.…But the depth z channel must have no…anti-aliasing, otherwise it'll introduce artefacts around the edge, okay?…Back to our story, I'll re-home viewer.…So lets add our z d focus node.…I'm going to select the read node, and I'm going to use the tab key to search for it.…

I'll type z and there's my z d focus node right on top.…