[1] Theoretical basis of confocal microscopy

A confocal microscope forms its image by recording light primarily from a small focal volume, largely ignoring points to the side or above or below. That volume, described as a point-spread function, is the product of two similar functions that are generated by the objective lens. Because of that multiplication, the recorded light is greater than even the integrated total of the light from all other points in a thick sample. Some of the implications of implementing this theory are reflected in the choices available to users of confocal microscopes.