The tutorial initializes with the Lamp Voltage slider set to a position that is slightly less than 50-percent of full intensity. The microscope is also in diascopic illumination mode, with the positioned to direct light to the camera system. Use the Diascopic and Episcopic radio buttons to toggle between illumination modes (transmitted and reflected light, respectively). The light path can also be adjusted with a virtual to direct light to the Eyepieces or Camera system by clicking on the appropriate radio button.

The microscope optical train typically consists of an illuminator (including the light source and collector lens), a substage condenser, specimen, objective, eyepiece, and detector, which is either some form of camera or the observer's eye. Research-level microscopes also contain one of several light-conditioning devices that are often positioned between the illuminator and condenser, and a complementary detector or filtering device that is inserted between the objective and the eyepiece or camera. The conditioning device(s) and detector work together to modify image contrast as a function of spatial frequency, phase, polarization, absorption, fluorescence, off-axis illumination, and/or other properties of the specimen and illumination technique. Even without the addition of specific devices to condition illumination and filter image-forming waves, some degree of natural filtering occurs with even the most basic microscope configuration.