Dave,
Thanks for the pictures. Apparently, this is still very close to the earlier Synchro Compur design, not much changed at all. The aperture is not adjustable, there's just one hole in the aperture control ring into which the pin goes that turns the ring holding the leaves. The limiters for min/max aperture are two rivets, which can be placed into different holes. I marked them in red on your picture. You obviously found out already that the three screws I marked blue release the control ring.
It might require some precision mechanics skills to change the limits since it is riveted. Anyway, the rivet on the right hand side (across from the pin) limits your max aperture since it is in the second hole. If it was in the first, the blades would open all the way. The rivet close to the pin limits your min opening.
Hope this helps somewhat,
Peter
Bookmarks