Point Resolution (or Point-to-Point, or Directly Interpretable
Resolution) of a microscope corresponds to the to the point when the
CTF first crosses the k-axis at the extended
scherzer defocus and can be expressed as:
Phase contrast images are directly interpretable only up to the point
resolution (Scherzer resolution limit).
If the information limit
is beyond the point resolution limit, one needs to use image
simulation software to interpret any detail beyond point resolution limit.