Gatan UltraScan 4000 Pixel Sizes Before October 2017

Pre-October, 2017

This table has columns that relate to the magnifications and pixel sizes of the JEOL JEM 3200FS and the UltraScan 4000 CCD camera. The first column shows the microscopes nominal magnification while the second shows the calibrated magnifications done using Gatan's DigitalMicrograph calibration routine. Note that this was only done for a limited number of the available magnifications. The third column shows the pixel sizes as reported by DigitalMicrograph (and these should correspond to pixel sizes shown in the dm3 metadata of each image). The fourth column shows the pixel sizes as determined using serialEM and a replica diffraction grating (a so-called waffle grid).

NOTE: The missing values in the 2nd column reflect magnifications that were not directly calibrated. The pixel sizes shown in the 3rd column are interpolated values unless there is a corresponding calibrated magnification. Pixel sizes shown in the 4th column were all directly determined.

NOTE: The pixel sizes shown in column 3 are those reported by Digital Micrograph (DM) and will almost always differ slightly (or even more than slightly) from those shown in column 4 (as determined using serialEM). This is a consequence of differences in the way the pixel size was determined and whether the pixel size is a direct measurement (all serialEM pixel sizes have been direcly measured) or an interpoated value (the only measured pixel sizes shown in DM are those that correspond to the calibrated magnifications). In general, the EMC staff trusts the values determined using serialEM more than those of DigitalMicrograph. Also, bear in mind that when the electron beam is not parallel, the 3200FS shows significant defocus-dependent magnification changes and thus the defocus of specific images will definitely affect the exact magnification of the recorded image.