In this article, Part 3 of a four part series, the noise sources for CCD, EMCCD, and scientific grade CMOS cameras are introduced and their impact on measurements described. The major noise sources are combined with signals calculated from a microscope/sample system to generate signal-to-noise ratios. To compare sensor performance, these ratios are plotted as a function of increasing exposure time, a commonly adjusted user parameter, for the three sensor types at the same pixel size and also with different pixel sizes characteristic of each sensor
