Question

What exhaustive stack focus method settings are available and how are they used?

Answer

The Exhaustive Stack focus method captures a deep stack of images for each field in a scan. The stack of the first field is centered around the initial focus selected at the beginning of the scan. The stack of each subsequent field is centered around the best focus of adjacent fields.

The Exhaustive Stack focus method is the slowest focus method but it generally achieves the best focus for the widest range of specimens.

Exhaustive Stack Focus Range Settings

The following settings control the exhaustive focus algorithm. You may change these parameters to suit your requirements.

• Initial — Range
  The Initial Range specifies the range (above and below the initial focus point) to scan for best focus of the initial field.
• Turnaround — Range
  The Turnaround Range specifies the range (above and below adjacent focus points) to scan for best focus of the first field in each column.
• Run — Range
  The Run Range specifies the range (above and below adjacent focus points) to scan for best focus.
• Run — Steps
  The Run Steps specifies the number of steps to move the objective for each image in the focus stack. The number of steps is based on the objective magnification and NA.

Note
The step size specifies the number of motor steps to move the objective (0.1984 microns per step). So, 10 steps are equivalent to 1.984 microns (0.001984mm). The step range specifies the range (in motor steps) above and below a mid-point. So, a step range of 20 is equivalent to 41 steps in total (20 motor steps above and 20 motor steps below the initial focus).

Refer to Step Size and Range Settings for more information.