Figure 3. Curves comparing the experimentally determined DQE(s) values for three older, commercially available direct-detection cameras; the curve for photographic film; and the theoretically best-possible curve for a pixelated camera.

Although more recent developments in camera performance have brought the values for all commercially available cameras closer to the theoretical limit, this figure nonetheless emphasizes the limiting way in which pixilation causes the DQE to fall off as the resolution increases. As is explained in the text, one can collect images at higher magnification in order that the sought-after (best) spatial frequency is no more than 0.4 or 0.5 of the Nyquist frequency, thus incurring a much smaller amount of falloff. In the future, it might be hoped that technology to interpolate the location of single-electron events (i.e. super-localization technology) might become more effective than what is currently available, thus overcoming the limitation set by pixelization. This is a redrawn figure, modified from one presented as Figure 4 in [76], which was prepared for us courtesy of Dr. Greg McMullan.