I have been using the OM system on witch you can use any position on the aperture ring and its OK . Being new to the FD system i was wondering if that was the same or to just use the stops on the ring and as stated in manual mode the needle will sometimes only sit centred in its notch if a between setting is used.On the OM1 any setting can be used to centre the needle and achieve a good exposure .
The click-stops are on the aperture ring, not the blade assembly. You can set intermediary positions a the ring, and the blades will follow that. But positioning the ring steadily between the arrests can be tricky.
With the breech-lock models you can easily control the working of the aperture without body:
-) close breech-lock ring
-) arrest aperture closing lever in closed position