FIGURE 4.

Cryo-ET data acquisition. (A) Typical multi-level imaging approach to tomography data acquisition. First images are acquired at the lowest magnification to obtain a grid overview or “low magnification montage (LMM); areas of interest are selected from LMM and imaged at intermediate magnification, often stitched together to produce a “medium magnification montage (MMM)”; targets are selected from MMMs and will be imaged at high magnification while tilting the stage. (B) Comparison of dose distribution among commonly used tilt schemes. Blue slices are earlier tilts in the sequence and have lowest total accumulated dose, red slices are latest tilts and have highest total accumulated dose. (C) Common strategies for object tracking during tilt series acquisition. In SerialEM each acquisition target has an associated tracking/focusing area shifted along the tilt axis. In Leginon multiple acquisition targets along a tilt axis can share a common tracking/focusing area. In PACEtomo within SerialEM a single tracking area can be shared for multiple acquisition areas without being constrained to a tilt axis; this approach is also implemented in TFS Tomo5 software.