The color image is an extended focus view of tennis ball fuzz (after having been played on about 1 set ). Even with the extended focus capabilities of our optical microscope, the transparent nature of the felt fibers makes it difficult to obtain an image that is in perfect focus through the entire depth of the material. The SEM shows a slightly different area of the fuzz













Since the secondary electron image is generated from the surface (“few” nanometers), the optically transparent fibers appear as solid strands. And because the wavelength of electrons is much shorter than the wavelengths of visible light, the SEM provides a much greater depth of field than the optical microscope.