Video 1

Movie S1. Evolution of the CTF during a beam-induced phase shift (BIPS) image series with a 12-nm–thick amorphous carbon film at the back-focal plane heated to ∼225 °C. The series start on a fresh area of the film. With each frame, the phase shift increases, which leads to movement of the CTF extrema inward. Acquisition parameters: beam current, 1 nA; beam diameter on the film, 1 μm; exposure time per frame, 2 s; defocus, 18-μm underfocus.