Provided is an optical apparatus that includes an illumination assembly which include an extended radiation source emitting radiation with a controllable spatial distribution and telecentric condensing optics, configured to receive and project the emitted radiation with a numerical aperture exceeding 0.3 along a first optical axis onto a field and an imaging assembly that includes a sensor and objective optics configured to image the field along a second optical axis onto the sensor and also a prism combiner positioned between the field and the condensing and objective optics which is configured to combine the first and second optical axes, while reflecting at least one of the optical axes multiple times within the prism combiner.