[3dem] 4k x 4k cameras

[Kasim Sader]

We did a test of a very stable icosahedral virus, alternating exposures from
CCD (Gatan US4000 single port) to film under the same electron optical
conditions from adjacent areas. Our CCD pixel size was less than 2angstroms
and the film scanned with a Zeiss SCAI. Our reconstruction from data
collected from film was much better than that collected by CCD visually and
by FSC (8 vs 14angstroms using ~2600 particles in each case).
 
There is no doubt that high resolution single particle data can be collected
on a CCD in a way that overcomes the limitations of the MTF (very high
magnification), but in terms of convenience of data collection this still
may be not better than the whole process of using film, unless automated
data collection is used to take the many more exposures needed.


Kasim Sader
SuperSTEM
Daresbury Laboratory
Warrington
UK