Special Operation setup¶

Taking final exposures on film¶

If film is used to collect data with one or more exposure presets, Edit the preset
setting in Presets Manager when you are ready to do so. The exposure time of the preset will
be applied to film exposure. A warning message will come up when the cassette is exhausted
and Leginon paused. You will need to reset the stock number after new film is added.

Acquiring images with the stage at a fixed alpha tilt¶

All targeting and focusing works on tilted specimen with correction made within Leginon
automatically.

• Z adjustment to the defocus allows images acquired from image-shifted targets to
  exhibit equivelent defocus regardless of location.

Additional <link linkend="mcal_st_pos">stage position matrix calibration</link> is
therefore needed for MSI at hl preset magnification where the targets are selected in
Hole node.

• Distortion correction is made to beam-tilted images that are used for autofocusing
  to boost peak signal.

Rotation centers are therefore needed to be stored at the magnification and HT for
fa and hl that are used in Z focus and Focus nodes for autofocusing, respectively. This
is <link linkend="r_center_store">stored (and retrieved) in Beam Tilt node of
Calibration application</link>. Because rotation center may change from day to day,
the correction is made only if the required rotation center is stored under the same
session.

**Because of the additional calibrations, this is not recommanded for
beginners.

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