Behavior in Version 2.3 and earlier:
In "Motion Amplification® " Acquisition Mode, when you have the "Camera Properties" Framerate field set to fps, Fmax will be half the entered frame rate. In "Displacement" mode, the "Framerate (fps)" field will change to read Fmax and it will display the actual Fmax value.
Version 2.4 UPDATE
To simplify the recording process, the Acquisition Mode and Lighting settings have been removed from the user interface. Now, Fmax will always be half the entered frame rate.
See the attached video to view this behavior.