FoCal is intended to provide help in calibration of the microadjustment value for a lens against a camera body.
Check out An Introduction to Autofocus for a run through of how autofocus works and why you need to calibrate.
If you haven’t yet installed the FoCal software, please have a look through the Getting Started with Boxed FoCal or Downloading FoCal to see how to download, or if you’ve already got the packages then Installing Reikan FoCal on Windows or Installing Reikan FoCal on Mac will guide you through the installation.
Continue on to Testing Location
How does FoCal help? | This Page | Testing Location