Contact probe hardware tends to be an assembly of well-defined mechanical components (probe mount point, probe body, probe module, probe tip) with predictable mount point and nominal tip offsets where position variances can be handled by the probing motion. However, vision probes are normally less predictable, as they often have non-standard mounting hardware, variances in the working distances, hardware adjustment or calibration, and so on. Because of this, it may be more difficult to find the desired target with probing motion. The vision probe does not scan the way contact probes to, so the variances are more noticeable.
Some machines may also have adjustable probe mounts that make the probe position unpredictable in the default probe.dat definitions. Because of such tight tolerances from higher magnifications or machine variances, you may need to do a manual+DCC execution the first time the probe offset is calibrated on a new probe tip, even if the tool position is known. This provides high quality measured offset data for subsequent tip offset calibration sequences, as the measured tip offset is used instead of the nominal.
Unlike most CMMs, most vision multi-sensor machines do not have a single standard end of arm probe mount. Instead they have a Z column that provides a proprietary mount for the optics and a standard mount for the touch probe. In order to define the nominal probe offset values with accurate relative offsets, an adaptor component is often used in the probe.dat or usrprobe.dat definition. This adaptor defines the offset between the machine probe reference point (such as end of ARM) and the probe. For example, if you were to select the zoom cell lens face as your reference point, you would need an adaptor component that defined the offset distance from the zoom cell lens face to the touch probe mount point. Then, to define a touch probe, you would select the adaptor, then the probe (such as a TP200), then the stylus. When finished, the nominal probe offset between the vision probe and the contact probe would approximate the hardware.