(a) DQE of three cameras.^[16]Gatan UltranScan Camera (black) is a traditional camera with a scintillator. The accumulation mode (blue) and counting mode (red) of the K2 camera represent the DDD linear camera and counting camera, respectively. Note that centroiding with half-pixel precision doubles the camera size. (b) Rotational average of the power spectrum of two images of Pt/Ir film, respectively taken with the linear accumulation mode (blue) and counting mode (red) of the K2 camera.^[28]The inset figure shows the spectrum SNR (SSNR) calculated from the two curves in the main figure, where the higher red curve (counting mode) confirms the DQE observed in panel (a).