What is the difference between setting a high FOV and using a Pannini or fisheye projection ? Does that mean there is less distortion towards the center ? I d

What is the difference between setting a high FOV and using a Pannini or fisheye projection ? Does that mean there is less distortion towards the center ? I did not watch the video yet... How difficult would it be to integrate a 170 pannini camera using shaders instead of using quake ? I don't understand why he used quake for this...