The problem I have is that I'm not sure which channel of the DCM map should be piped into Depth of Field SOP. I tried Depth-Complexity (no effect), Pz (treats semi-transparent objects as opaque), P (no effect).
Normally, for opaque objects I'd just pipe in Pz.

What is the proper way of compositing DCM to get the DOF effect in the COP network?

Or maybe I'm rendering it wrong? I have DCM selected as Deep Resolver and path+file name specified. DCM Pre-Composite Samples is off (I tried with Pre-Composite enabled, but it didn't change much).
In the manual I found this:

DCM tips
(…)
- Every object needs its own DCM.
- Use $OS (name of the current node) in the DCM file name to keep DCMs separate.

So I added Mantra->Deep Output render parameters to every geo object in my scene, set the resolver to DCM and filename to $OS_dcm.rat, but none of those maps gets rendered out.

Hm, it looks like Deep Camera Map doesn't like opacity in the Mantra Surface Shader.
I have a character with some fur that uses poly sheets and cutout maps, and DCM always treats my fur objects as being out of focus.
Is there any workaround for this?

Also, I encountered a weird problem. Whenever I render to file with DCM, my output image gets extremely aliased, like there were not enough ray and pixel samples. But if I turn DCM rendering off, the output image looks perfectly fine.
Why does this happen? Do I have to render the same frame twice - with and without DCM?

It would be better if you can create a simple test file for us. So far in testing I haven't seen DCM file affect the RGB output.

Interpolation dosen't always make sense for Deep but I'm not sure if this is the case here.

MartybNz
It would be better if you can create a simple test file for us. So far in testing I haven't seen DCM file affect the RGB output.

Interpolation dosen't always make sense for Deep but I'm not sure if this is the case here.

Here's a test scene. Render out both mantra ROPs and compare “render_with_dcm.pic” and “render_without_dcm.pic” images in MPlay. Zoom-in on edge of the sphere and you'll notice aliasing in the “_with_dcm” file despite the settings in both ROPs being the same.

Ya - my guess is that as Deep doesn't like smooth interpolation and Mantra is binning the rgb and deep sub-pixel files with a box-like filter. Worth an Rfe.