Easy, non technical method to tell if your leaf shutter is in need of servicing. Position the shutter so that you can see the shutter blades and an analog clock with a second hand at the same time.
Set the speed dial to 1 (second), cock the shutter. When the second hand reaches a second mark trip the shutter. The shutter should open then close just as the second hand reaches the next second mark.
Thanks. That would be a good suggestion except that it isn't needed. One second is roughly how long it takes to say "one thousand" and the shutter stays open no longer than it takes to say "on".