 | Acta Crystallographica Section D Acta Crystallographica Section D BIOLOGICAL CRYSTALLOGRAPHY |
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![[Figure 2]](ba0034fig2mag.jpg)
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Figure 2
Contrast transfer functions are shown for five imaging conditions. All functions are shown for a microscope operating at 200 kV (λ = 0.0253 Å), a spherical aberration (Cs) of 2 mm and an amplitude contrast ratio of 0.1. The curves shown represent: B, an underfocus of 200 Å and a source size of 0.01 Å−1; C, an underfocus of 2000 Å and a source size of 0.01 Å−1; D, an underfocus of 20000 Å and a source size of 0.05 Å−1; E, an underfocus of 20000 Å and a source size of 0.005 Å−1; F, an underfocus of 200000 Å and a source size of 0.005 Å−1. The coherence of the source decreases as the source size increases. The use of underfocus results in the amplitude contrast and the first peak of the phase contrast having the same sign. |
![[Figure 2]](ba0034fig2.jpg)
| BIOLOGICAL CRYSTALLOGRAPHY |
ISSN: 1399-0047
