ABSTRACT
This chapter deals with the technical aspect of cellular bio-imaging, including fluorochromes. A modern infinity-corrected optical microscope consists of an objective and a tube lens to form the image, with an ocular to gain magnification. The fields are bright field, dark field, phase contrast, differential interference contrast and epifluorescence. Confocal microscopy, using a sophisticated epifluorescence microscope, resolves two major problems: it reduces the depth of field and eliminates light from out-of-focus objects. The confocal scheme blocks out from the detector all light coming from outside the focal plane. The transmission electron microscope images a thin specimen in a high vacuum by focusing an electron beam with electromagnetic fields. A photomultiplier tube has a photo-sensitive photocathode in a vacuum behind a glass window. Inversely, some cameras allow switching to black and white mode to gain sensitivity on the three detectors, somewhat like electronic binning, while others offer this only as a way of simplifying the data and its storage.
