A high speed fluorescent emission imaging digital microscope has an Argon-Ion UV laser illumination source and a high speed optical filtering wheel in the illumination path to alternately select between two UV illumination wavelengths to produce fluorescent emission images at each UV wavelength. A dichroic reflector directs emission images along an image path and an galvanometer rotatable mirror exposes each image on a predetermined area of a CCD. A computer controls the rotatable mirror in response to exposure timing information from the filtering wheel. An objective lens is focused on the specimen for producing an image from a particular focal plane of the specimen. The objective lens is mounted on a counterweighted piezoelectric objective translator for changing the focal plane of the specimen image in response to control signals from the electronic processor.