An imaging system is disclosed including a first illumination source for producing a first illumination field, a modulation system for modulating the first illumination field, and an optical imaging system for directing the modulated illumination field to an imaging surface along a first optical path. In accordance with an embodiment, the imaging system includes a second illumination source for producing a second illumination field, a first sub-assembly, a second sub-assembly and a control assembly. The first sub-assembly is for directing the second illumination field toward the imaging surface along a second optical path that is different than and non-parallel with said first optical path. The first sub-assembly includes a beam splitter sub-assembly that includes a beam splitter and at least one lens. The second sub-assembly is for receiving a portion of the second illumination field from the imaging surface, and includes a lens and a sensor for producing a sensor output signal. The control assembly is for adjusting a focal point of the optical imaging system responsive to the sensor output signal.