Question

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

Answer

The Fast Stack focus method captures a short stack of images for each field in a scan. The stack is centered around the initial focus selected at the beginning of the scan.

The Fast Stack focus method is much faster than the Exhaustive Stack focus method and performs well for very flat, very thin sections. By default, the Fast Stack settings capture one image above and below the initial focus point and then compares them to determine the best focus.

Fast Stack Focus Range Settings

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

• 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.
• Run — Range
  The Run Range specifies the range (above and below the initial focus point) to scan for best focus.

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.