(a) An image of a frozen hydrated archaeal 20S proteasome sample taken on a TVIPS F816 traditional CMOS camera with 1.6 μm defocus and 200 kV accelerating voltage, and (b) its power spectrum. Panels (c) and (d) are similar to panels (a) and (b), respectively, but were taken with a K2 summit counting camera with 1.1 μm defocus and 300 kV accelerating voltage.