A comparison of the transmission-type electron microscope with the similar light microscope has to include considerations of the differences in the nature of the carrier of radiant energy and of the optical media used for building up the optical systems. Although electron optics is of relatively recent origin, fairly good agreement of the experimental limits with the theoretically expected ones has been obtained. After a discussion of existing discrepancies, proposals and attempts for improving the performance of the electron microscope are outlined.
L. MARTON, "Electrons vs. Photons: A Comparison of Microscopes," J. Opt. Soc. Am. 40, 269-274 (1950)