Sorry, but I don't get the last message.
Corona calculates DOF physically (I guess it is pretty much like letting light through a small hole on a plate) based on photographic parameters: sensor size, f size, target distance,... . You can see exactly the same parameters in Corona's "scene" settings, and in 3ds Max physical camera. It does not make any difference whether you are using the "scene" settings or camera settings, as exactly the same parameters are considered, exactly the same method is used, and exactly the same renderer is used. It's like having exactly the same settings in two different places. I hope it's clear. :)