Did two renders, one normal and one with ray-traced DOF.  In the latter, all the shadows came out hard, regardless of the light and soft-shadow settings, unlike the normal render, which had soft shadows and good shadow bias. Is this a Carrara shortcoming, or am I missing some needed parameter when using ray-traced DOF?  Little help, please.

 What version of Carrara are you using?

I'll poke around a little. Are the hard edge shadows in reflected objects or visible things further away from the camera?

The light settings for both renders were the same.

 There are a couple of ways to handle this. One is to increase the fidelity of your light effects Raytraced soft shadows to Best. The other way is to switch from Raytraced shadow mode to Shadow Buffer mode and jockey the settings around slightly. 

Not ideal but these methods will work.

From what I can tell, it looks like the Raytraced DOF forces soft shadows to to become truncated - that is, it eliminates the number of instantiated multiple lights that are responsible for actually making soft shadows. I'm filing a bug for it. Good catch!

Mark

Great looking render.