In Poser the Dolly camera is where the dials say it is. Unfortunately that is not the case with the Main or Aux camera. In P6, when the Main or Aux camera is scaled to 100%, the camera is approximately 1.1  Poser Native units (about 2883.4 mm) behind the position indicated on the zDolly dial. This only applies to zDolly, and it is the value for P6, it is probably the same in later versions, but I can't guarantee that.