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. 2008 Mar 13;363(1500):2153–2162. doi: 10.1098/rstb.2008.2268

Figure 1.

Figure 1

Three types of phase contrast methods. (a) Schematic illustrating the DPC with conventional TEM, in which contrast is adjusted by altering the defocus. (b) Contrast transfer function (CTFs) corresponding to DPC plotted against the modulus of the spatial frequency (k). (c) Schematic illustrating ZPC using a Zernike phase plate set at the back focal plane (BFP). (d) CTFs corresponding to ZPC plotted against the modulus of the spatial frequency (k) at the BFP. (e) Schematic illustrating the HDC using a Hilbert phase plate (semicircular phase plate) set at the BFP. (f) A CTF corresponding to HDC plotted against a unidirectional spatial frequency (kx). (b,d,f) 300 kV, λ=0.001968 nm and Cs=3 mm. Adapted from fig. 1 of Danev & Nagayama (2006).