Long Press Duration - pref?

What is the default duration for the 'long press' trigger to be acknowledged?
Is this definable in the prefs?

If you need finer control over key presses, specifically the duration of presses, you might get some ideas from a macro I submitted on another thread:

The macro at the bottom of that thread discusses how to control duration requirements for multiple clicks, not a single click, but it wouldn't take much modification to have it adapted to work with "long presses".