Cryo-EM of molecules in single-particle form is increasingly used to look at the dynamic behavior of molecular machines such as the ribosome, by depicting them in a series of three-dimensional "snapshots". The number of images required in each reconstruction is roughly proportional to the third power of resolution, with the largest amount of computation going into the refinement of orientations. Against the background of recent results on the structure and function of the ribosome, strategies of automation, algorithmic optimization, and computation in cryo-EM will be discussed.