Open AccessMagnification variations due to illumination curvature and object defocus in transmission electron microscopy
Author(s) -
G. van Duinen,
Marin van Heel,
Ardan Patwardhan
Publication year - 2005
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/opex.13.009085
Subject(s) - magnification , optics , curvature , microscopy , electron microscope , microscope , physics , depth of field , mathematics , geometry
It has previously been shown that - in theory - magnification variations can occur in an imaging system as a function of defocus, depending on the field curvature of the illuminating system. We here present the results of practical experiments to verify this effect in the transmission electron microscope. We find that with illumination settings typically used in the electron microscopy of biological macromolecules, systematic variations in magnification of ~ 0.5% per microm defocus can easily occur. This work highlights the need for a magnification-invariant imaging mode to eliminate or to compensate for this effect.