Therefore, researchers adjust the excitation of the objective lens so as to produce an image of the diffraction pattern in the middle of the beam separator and choose the desired spot intensity to image using a contrast aperture inserted there. This aperture allows scientists to image diffraction intensities that may be of particular interest (dark field).

Illumination optics are employed to magnify the image or diffraction pattern and project it onto the imaging plate or screen.Imaging plate or screen used to image the electron intensity