CTFFIND is a widely-used program for the estimation of objective lens defocus parameters
from transmission electron micrographs. Defocus parameters are estimated by fitting a
model of the microscope's contrast transfer function (CTF) to an image's amplitude spectrum.
Here we describe modifications to the algorithm which make it significantly faster and more
suitable for use with images collected using modern technologies such as dose fractionation
and phase plates. We show that this new version preserves the accuracy of the original …